HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Search for Related Content Social Bookmarking                      What's this?

Cardiopulmonary

Nishino M.; Kubo T.; Kataoka M.L.; Yoshimura N.; Raptopoulos V.; Hatabu H.; Radiology, Beth Israel Deaconess Medical Center, Boston, MA.

Address correspondence to M. Nishino (mnishino{at}bidmc.harvard.edu)

Background: Due to recent advances in MDCT technology with improved spatial and temporal resolution, there has been a growing trend in using multiplanar reformation CT images to evaluate thoracic abnormalities. Newer MDCT scanners such as the 64-row MDCT, with more increased volume coverage and a thinner detector collimation with near isotropic voxels, provide multiplanar reformation images of the chest with even more improved image quality and diagnostic capability. In this exhibit, we describe a variety of unique demonstrations of thoracic abnormalities on coronal reformations using a 64-row MDCT, and discuss advantages and disadvantages of coronal reformations in making diagnosis of thoracic abnormalities in comparison with conventional axial images.

Key Issues: Based on our experience with the newest 64-row MDCT in clinical thoracic imaging, we describe a wide variety of unique demonstrations of thoracic abnormalities on coronal reformations, including vascular abnormalities such as aortic diseases and pulmonary embolism; cardiac abnormalities such as coronary artery calcification and stenosis; mediastinal masses and lymphadenopathy, pleural and chest wall diseases; and parenchymal abnormalities such as nodules, masses, consolidation, emphysema, bronchiectasis, and interstitial lung diseases. Volumetric coronal images with thin collimation are displayed using a cine display. The advantages and disadvantages of coronal reformations in making a diagnosis of these thoracic abnormalities are al so described in comparison with conventional axial images.

Format: The exhibit will be didactic, describing various thoracic abnormalities on coronal reformations on 64-row MDCT, along with the advantages and disadvantages in comparison with conventional axial images. "Exercise Cases" are provided at the end, allowing for self-assessment opportunities.

Teaching Points: 1. To become familiar with a variety of unique demonstrations of thoracic abnormalities on coronal reformations using a 64-row MDCT. 2. To understand the advantages and disadvantages of coronal reformations in making diagnosis of thoracic abnormalities in comparison with conventional axial images.

E024. Multidetector CT Imaging of Central Airway Neoplasms

Lee K.S.¹; Feller-Kopman D.²; Ernst A.²; Boiselle P.M.¹; 1. Radiology, Beth Israel Deaconess Medical Center, Boston, MA; 2. Pulmonary Medicine, Beth Israel Deaconess Medical Center, Boston, MA.

Address correspondence to K.S. Lee (kslee{at}bidmc.harvard.edu)

Background: Multidetector CT offers a powerful, non-invasive method of assessing endotracheal and endobronchial neoplastic lesions.

Key Issues: This exhibit will illustrate and describe the spectrum of benign and malignant primary central airway neoplasms with CT-bronchoscopic correlations. Emphasis will be placed on the use of multiplanar reformations and advanced 3-D reconstruction techniques in aiding diagnosis and pre-procedural planning of central airway neoplasms.

Format: This electronic exhibit will use both didactic and interactive methods. It will be organized in the following manner: 1) Introductory section on central airway neoplasms and how patients clinically present. 2) Role of multidetector CT in the imaging assessment of patients with suspected central airway neoplasm. 3) Features of benign vs. malignant airway neoplasms. 4) Examples of specific benign and malignant airway neoplasms with CT-bronchoscopic correlation.

Teaching Points: 1) To illustrate and review the spectrum of benign and malignant primary central airway neoplasms. 2) To highlight the role of advanced CT reconstruction methods including CT bronchography and virtual bronchoscopy in aiding pre-procedural planning and diagnosis.

E025. Role of CT Venography and CT Pulmonary Angiogram in Detecting Thromboembolic Disease

Nair S.; Sebastian A.; George C.; Mannion R.; Radiology, York General Hospital, York, United Kingdom.

Address correspondence to S. Nair (drsnnair{at}hotmail.com)

Objective: Multislice CT pulmonary angiography (CTPA) has become the investigation of choice in patients with suspected pulmonary embolism (PE). The association of PE and deep vein thrombosis (DVT) is well known. Recent research has shown that in patients suspected of having PE, a reasonable number of patients had DVT in the absence of PE. Combining CTPA and CT venography (CTV) supposedly increases the detection rate in these cases and thus has a significant effect on patient management. The purpose of this study was to evaluate whether the addition of CTV provided any additional diagnostic value over and above CTPA.

Materials and Methods: Retrospective review of all consecutive cases Dec2004-April 2005.

Results: 160 consecutive patients (M:F 68:92, mean age 66.1yrs, range 21-97 yrs) underwent CTPA and CTV from Dec 2004-Apr 2005. PE was detected in 31/160 (19.3%) patients at CTPA, and DVT was detected in 7/160 (4.37%) patients at CTV. Among 7 patients with DVT, PE was detected in 6 patients at CTPA. Combining CTV to CTPA resulted in only 0.7% incremental increase in thromboembolic disease detection compared with that at CTPA alone. Incidental findings include bladder carcinoma n = 1 and colitis distal colon n = 1.

Conclusion: Combining CTV with CT PA does not add any significant value in the diagnosis of thromboembolic phenomena. It increases the effective dose to the patient and the cost.

E026. CT Angiogram to Rule Out PE - Stop the Madness

Costantino M.M.; Gosselin M.; Brandt M.S.; Diagnostic Radiology, Oregon Health & Science University, Portland, OR.

Address correspondence to M.M. Costantino (costanti{at}ohsu.edu)

Objective: The high rate of negative pulmonary CT angiograms to rule out PE at our institution led to a review of all of the CTAs that had been performed over the previous 2 years. We were particularly interested in the rate of negative scans preformed on women younger than 35, in whom increased radiogenic breast cancer is of concern.

Materials and Methods: We conducted a retrospective chart review of 630 hospitalized (45%), ED (42%) and clinic (14%) patients who underwent CTA to rule out PE over the course of two years at our institution. We reviewed demographic data, assigned each patient a clinical probability using the Wells clinical criteria, reviewed CTA results, and evaluated the results of the d-dimer.

Results: Data show an 8.85% rate of positive CTA for PE (8.53% ED, 11.83% inpatient, 1.18% outpatient). A d-dimer was obtained on 36% of patients. Of d-dimer results 17% were negative, 47% were intermediate and 36% were positive. We assume that the ordering physician deemed patients who did not undergo d-dimer testing high clinical probability. In assigning clinical probability we found, of 630 patients 3 (0.51%) were high clinical probability, 282 were intermediate clinical probability (48%) and 300 were low clinical probability (51%). Seventy-seven (12.22%) of studies were preformed on women < 35 and 3 (3.89%) of these studies were positive.

Conclusion: Several years of observing the high rate of negative CTAs led us to review CTA results for the previous two years. We found that clinicians are not appropriately applying Well's criteria and are deeming the majority of patients "high clinical probability" when our data show that very few meet high clinical probability criteria. "High clinical probability" patients are most likely deemed as such because of what has been referred to as a "best clinical guess," and not because validated criterion are being applied. Second, given the very low rate of PE in the cohort of women < 35 years old, clinicians should ardently seek other explanations for the patients symptoms before ordering the CTA, and the radiation that comes with it, in this cohort. Finally, the high rate of intermediate d-dimer results emphasized the importance of clinical probability. In a truly low clinical probability patient, the clinician may wish to forego the d-dimer and thereby prevent necessary further work-up for PE if the d-dimer result is intermediate.

E027. Image Post Processing Techniques in Multi Detector Row CT (64-slice) Coronary Angiography

Sirineni G.KR.; Pottala K.M.; Kalra M.K.; Cann A.D.; Syed M.; Tigges S.; Department of Radiology, Emory University School of Medicine, Atlanta, GA.

Address correspondence to G.KR. Sirineni (sgkreddy{at}yahoo.com)

Background: 64-slice MDCT coronary angiography produces a large isotropic dataset (n = 375-400 images for each phase), to be interpreted. Interpretation solely from axial source images has become both impractical and insufficient to fully exploit the clinically available data.

Key Issues: 64-slice MDCT coronary angiography produces a large isotropic dataset (n = 375-400 images for each phase), to be interpreted. Interpretation solely from axial source images has become both impractical and in sufficient to fully exploit the clinically available data. There are several post-processing techniques for MDCT coronary angiography, such as multiplanar reconstructions (MPR), curved planar reconstructions (CPR), maximum intensity projections (MIP), surface shaded display (SSD), volume rendering (VR), and virtual angioscopy (VA). The MPR, CPR and MIP are two-dimensional (2-D), whereas, SSD, VR and VA are three dimensional (3-D) representations of the data. The MPR and CPR are most often used for diagnostic review of atherosclerotic plaques, vessel dimensions, stents and to grade stenosis. The MIP, 3-D VR, SSD and VA techniques give excellent overview of coronary anatomy and are useful for evaluation of bypass grafts and coronary anomalies. These latter techniques are often useful for referring physician review, although care must be taken to avoid misleading images. Most techniques are semi-automatic, which require some degree of user intervention.

Format: The purpose of this didactic educational exhibit is to illustrate various post-processing techniques available for CT coronary angiography and discuss their strengths and limitations in detection of coronary artery disease. The automatic segmentation and vessel tracking tools that simplify the laborious manual processing will also be described.

Teaching Points: 1) To describe various image post-processing techniques for MDCT coronary angiography. 2) To recognize the strength, pitfalls and limitations of each post-processing technique.

E028. Normal Coronary Arterial and Venous Anatomy with High Resolution CT Angiography

Kini S.; Kucej B.D.; Weaver L.; Bis K.G.; Radiology, William Beaumont Hospital, Royal Oak, MI.

Address correspondence to S. Kini (kini{at}musc.edu)

Background: Contrast enhanced computed tomography (CT) of the coronary arteries is becoming feasible as temporal and spatial resolution improves with the availability of multi-detector row CT. Detection, characterization, and quantification of coronary artery disease as well as elegant delineation of coronary anatomy is possible using 2D maximum intensity projection (MIP) and 3D volume rendered (VR) post-processingtechniques. Familiarity with coronary artery and venous anatomy as well as anatomic variants is important for correct image interpretation. Such arterial variants have been well-described using conventional angiographic techniques. However, the cross-sectional nature of CT has the benefit of more precisely displaying the spatial relationships of coronary arterial and venous anatomy with respect to cardiac structures.

Key Issues: Imaging was performed with a Siemens 64-slice CT scanner after pre-medication with oral atenolol (50-100 mg) and/or IV metoprolol (5-10 mg boluses, up to 50 mg). Bolus timing was measured in the mid-ascending aorta with 20 ml contrast (Visipaque) (5 ml/sec followed by a 50 ml saline flush at 5 ml /sec). Coronary CTA was performed 5 seconds after aortic peak density (100 ml Visipaque at 5 ml/sec, followed by 50 ml of saline flush at 5 ml/sec). Retrospective ECG-gating was employed (collimation 0.6 mm, tube rotation time 0.3 sec, table feed/rotation 7.68 mm, tube voltage 120 mV, effective mAs 750-850, pitch 0.2). Reconstruction FOV, slice thickness/reconstruction increment and kernels were as follows: 15-22 cm, 0.6 mm/0.3 mm, B25 f smooth. Prospective analysis of clinical cases referred for coronary CTA was made and cases were selected to demonstrate the normal coronary arterial and venous anatomy. Maximum intensity projections were obtained utilizing variable thickness (5-30 mm) and displayed using standard orientations (RAO,LAO, Axial, Spider) as were 3D-VR images in a variety of projections.

Format: A tutorial format will be used displaying labeled MIP and 3D VR images on PowerPoint software.

Teaching Points: The goals of this educational exhibit are to 1.) Highlight our coronary CT-angiography (CTA) protocol and 2.) Demonstrate the normal arterial and venous coronary anatomy along with anatomical variations with 2D-MIP and 3D-VR images using a high resolution 64-slice CT scanner.

E029. Coronary Artery Computed Tomographic Angiography with Conventional Angiographic Correlation-Anatomy, Normal Variants, and Anomalies

Javidan C.¹; Bhalla S.¹; Gutierrez F.R.¹; Seeck B.A.²; Billadello J.²; Woodard P.K.¹; 1. Department of Radiology-Section of Cardiothoracic Radiology, Mallinckrodt Institute of Radiology-Washington University School of Medicine, St. Louis, MO; 2. Department of Internal Medicine-Section of Cardiology, Washington University School of Medicine, St. Louis, MO.

Address correspondence to C. Javidan (javidanc{at}mir.wustl.edu)

Background: Coronary artery disease (CAD) results in high annual mortality and morbidity in the United States. The need for early diagnosis and treatment results in the need for faster and less invasive ways of CAD diagnosis. Conventional angiography has been the main imaging modality to image the coronary arteries, however being an invasive procedure, it has risks of its own. High temporal and spatial resolution required to image the coronary arteries of a beating heart has been achieved with 16- and 64-multidetector row computed tomography (MDCT). Post-processing software available to create 3-dimentional CT angiography is currently used by radiologists to evaluate the vasculature. As coronary CTA becomes more widely available, it is essential for the radiologist to become familiar with normal coronary anatomy and anatomic variants in order to provide an accurate description and interpretation of disease. Since traditionally the coronary arteries have been depicted by angiography, both CTA and conventional angiography appearance of normal, variant, and anomalous coronary arteries will be shown.

Key Issues: This exhibit will focus on anatomic features of the coronary arteries, while educating the reader of normal anatomy and variants of coronary arteries as depicted on axial and CTA images. Anomalies of coronary arteries will be described and examples will be provided, while explaining their clinical significance.

Format: The format of this presentation will be both didactic and interactive, to emphasize the teaching points.

Teaching Points: 1. The radiologic appearance of normal coronary arteries and their branches, the normal variants and anomalies of the coronary arteries, as depicted by axial MDCT imaging and CTA. 2. New nomenclature of the coronary arteries and their branches and the variants would be discussed to correlate with what is currently used in coronary angiographic literature.

E030. ECG-gated 64 Slice MDCT in the Preoperative Evaluation of Patients prior to Minimally Invasive Surgery for Atrial Fibrillation

Meyer C.A.; Wolf R.K.; Vagal A.S.; Mehall J.R.; Schneeberger E.W.; Strunk R.S.; Radiology, University of Cincinnati, Cincinnati, OH.

Address correspondence to C.A. Meyer (meyerca{at}healthall.com)

Background: Atrial fibrillation is the most common arrhythmia associated with significant morbidity; it occurs in up to 5% of individuals greater than 60 years of age. Newer treatment options for atrial fibrillation have generated renewed interest in non-invasive cardiac imaging of these patients. The recent radiology literature has concentrated on the application of MDCT techniques to characterize the left atrium prior to catheter-based ablative therapy. However catheter ablation in the electrophysiology lab is a challenging technique with lengthy fluoroscopic procedure times. At our institution, a novel, minimally invasive, video-assisted surgical approach, the Wolf mini-Maze procedure, is performed for treating atrial fibrillation. These patients undergo a comprehensive preoperative cardiac evaluation using ECG gated 64 slice MDCT.

Key Issues: The new minimally invasive robotic surgery is used to access and map the left atrium and isolate the region responsible for the arrhythmia using a bipolar radiofrequency clamp. We will document our experience in the first 50 patients preoperatively evaluated with 64 slice MDCT. We will discuss the range of cardiac findings, 25% of which altered the surgical management. These findings include coronary artery disease, atrial thrombus, tricuspid regurgitation, grafts overlying the left atrium and atrial septal defect. Moreover, MDCT of an arrhythmic heart is very challenging. We will describe the technique we have developed to overcome the artifacts caused by tachycardia and arrhythmias.

Format: The organizational structure of this educational exhibit will be didactic. We will describe the novel Wolf mini-Maze procedure. Technical factors pertinent to imaging the patient with atrial fibrillation will be discussed. Finally, we will demonstrate the range of cardiac findings at 64 slice MDCT with emphasis on those findings that have resulted in a change in surgical management

Teaching Points: 1. To explain the Wolf mini-Maze procedure, a minimally invasive, video assisted surgical treatment for atrial fibrillation. 2. To review MDCT imaging complexities unique to atrial fibrillation patients. 3. To discuss imaging findings that will alter the surgical approach in the management of atrial fibrillation.

E031. ECG-Gated Multidetector Cardiac CT: Anatomy and Terminology for Interpretation and Reporting of the Coronary Arteries and Cardiac Chambers

Sundaram B.; Patel S.; Cascade P.; Moscucci M.; Eagle K.; Kazerooni E.A.; Radiology Department, University of Michigan Health System, Ann Arbor, MI.

Address correspondence to B. Sundaram (sundbask{at}umich.edu)

Background: Cardiovascular disease is the number one cause of death in the US. Current tests for coronary artery disease include non-invasive screening tests (treadmill, echocardiography) which provide indirect evidence of disease. Catheter coronary angiography is the gold standard test, providing direct evaluation of the coronary artery lumen, but is an invasive and expensive, with associated morbidity. With the recent advent of 64-slice CT scanners, CT coronary angiography has become a robust technique for evaluating the coronary arteries, with the potential to revolutionize the way coronary artery disease is diagnosed. CT provides not only information about the arterial lumen, as seen with catheter angiography, but provides information about the arterial wall. This creates the potential to characterize plaque by attenuation characteristics (soft tissue, fat, calcified), quantify plaque burden (which may be useful with in patients taking pharmaceutical agents designed to reduce plaque) and identify vulnerable plaque. From the same acquisition on which the coronary arteries are evaluated, data is processed to measure cardiac function, including left ventricular ejection fraction, as well as cardiac architecture, such as left ventricular mass.

Key Issues: To interpret cardiac CT examinations, readers must know coronary artery anatomy, anatomy/function of the cardiac chambers/valves, and types of abnormalities encountered, and the correct terminology for describing them. This exhibit will describe and illustrate 1) the normal anatomy of the coronary arteries and cardiac chambers, and common variants, and 2) the correct terminology for reporting abnormalities of the coronary arteries and wall motion, using existing guidelines, including those from the American Heart Association.

Format: Didactic. CT appearances of the anatomy and the abnormalities and the correlative terminology to describe the abnormalities.

Teaching Points: The viewer will learn to describe the anatomy and terminology for interpretation and Reporting of the Coronary Arteries and Cardiac Chambers.

E032. Protocols for Coronary CT Angiography (CTA)

Rybicki F.J.¹; Lell M.M.²; Ersoy H.¹; Streeter J.¹; Bae K.T.³; 1. Cardiovascular Imaging Section, Brigham and Women's Hospital, Boston, MA; 2. Radiology, Washington University School of Medicine, St. Louis, MO; 3. Radiology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany.

Address correspondence to F.J. Rybicki (frybicki{at}partners.org)

Background: The increased utilization of 16- and 64-slice MDCT technology has resulted in an increased number of patients undergoing coronary CT angiography(CTA). The purpose of this educational exhibit is to review scanning protocols and focus on parameters that vary between CT vendors.

Key Issues: Successful coronary CTA requires strict adherence to imaging protocols. Detailed 16- and 64-row slice protocols from the major CT vendors are presented. Parameters highlighted include: test bolus vs. bolus tracking, field of view for imaging native coronaries and bypass grafts, effective mAs, kV, and reconstruction parameters. Understanding relationships between contrast injection parameters (total volume, iodine concentration, flow rate, duration of injection, and dual injection) are also important to optimize protocols. Differences between coronary CTA images obtained from 16- and 64-slice scanners are illustrated.

Format: Didactic. For some parameters (e.g., mAs, kV), suggested values for the different platforms will be tabulated to point out similarities and differences. In other cases (e.g., test bolus vs. bolus tracking), illustrations will be used to highlight the advantages and disadvantages of different techniques.

Teaching Points: 1. Cardiac CT protocols for 16- and 64-slice CT. 2. Differences in acquisition and reconstruction among different MDCT scanners. 3. Principles of MDCT contrast dose optimization.

E033. 64-Slice MDCT in Imaging of Coronary Anomalies

Pottala K.M.; Sirineni G.K.; Kalra M.K.; Cann A.D.; Syed M.A.; Tigges S.; Department of Radiology, Emory University School of Medicine, Atlanta, GA.

Background: Coronary anomalies are anatomic variants that occur in 1% of general population and most of these anomalies are not clinically significant. However certain malignant forms of coronary anomalies with interarterial courses and origin of coronary arteries from the pulmonary artery can lead to increase in risk of myocardial ischemia and sudden death. Conventional coronary angiography was considered to be the gold standard technique in the evaluation of these congenital coronary anomalous vessels. However the anomalous vessel may be overlooked or assumed to be occluded if not selectively engaged during angiography. The complex course of the vessels can not be delineated properly because of its two dimensional display. The MDCT scanners can display the coronary anatomy in three dimensional view and the relation of these malignant forms of coronary anomalies to great vessels and cardiac chambers can be delineated accurately.

Key Issues: Coronary anomalies are broadly classified into origin and course anomalies of the coronary artery segments, anomalies of only coronary artery origins, origin and course anomalies of peripheral coronary segments and arteriovenous fistulas. The 64-slice MDCT with the multiplanar reformations, maximum intensity projections, volume rendering and virtual endoscopy images of high quality can delineate the origin and course of the anomalous coronary arteries, which is useful for the catheter based interventional or surgical therapy planning.

Format: Didactic.

Teaching Points: 1.The clinical importance of the various coronary artery anomalies 2.The diagnostic value of 64 slice MDCT coronary angiography in delineation of coronary artery anomalies.

E034. Assessment of Vessel Wall Remodeling with 64-slice CT Coronary Angiography and IVUS Correlation

Pugliese F.¹; Cademartiri F.¹; Meijboom W.B.²; deFeyter P.J.²; Krestin G.P.¹; 1. Department of Radiology, Erasmus Medical Center, Rotterdam, Netherlands; 2. Department of Cardiology, Erasmus Medical Center, Rotterdam, Netherlands.

Address correspondence to F. Pugliese (francesca.pugliese{at}libero.it)

Background: Direct non-invasive imaging of atherosclerotic plaques may significantly improve risk stratification of adverse coronary events and may prove useful for better understanding of the development and progression of coronary atherosclerosis.

Key Issues: Advances in understanding the pathophysiology of coronary artery disease have established that over 75% of plaques that rupture and result in acute coronary syndromes such as unstable angina and acute myocardial infarction (vulnerable plaques) are less than 50% occlusive. This type of plaques is reported to be far more prevalent than occlusive plaques. The 64-slice MDCT appearance of vessel compensatory enlargement (positive remodeling) and negative remodeling processes and their location along the coronary tree will be described with IVUS correlation. The feasibility of calculating a MDCT remodeling index will also be addressed.

Format: The steps of atherosclerotic plaque formation in coronary arteries will be reviewed focusing on findings assessable at 64-slice MDCT and IVUS. Positive and negative remodeling processes as they appear at 64-slice MDCT will be depicted and correlated to IVUS.

Teaching Points: The capability of early noninvasive assessment of the presence of vulnerable lesions in coronary arteries is of clinical relevance. The reader will be made familiar with clues for the assessment of extent, severity and localization of coronary plaques either non-obstructive due to arterial wall compensatory remodeling or impacting on the coronary lumen. Potentially vulnerable lesions will also be addressed on the basis of different CT densities.

E035. Imaging of Diastolic Function: Electronic Exhibit

Abdel-Malek P.M.¹; Varadarajan P.²; Pai R.²; Colletti P.M.¹; 1. Radiology, University of Southern California, Los Angeles, CA; 2. Medicine, University of Southern California, Los Angeles, CA.

Address correspondence to P.M. Abdel-Malek (abdelmal{at}usc.edu)

Background: Diastolic function reflects the ability of the ventricles to receive an adequate volume with low filling pressure over a wide range of loading conditions and heart rates. Diastolic function parameters include isovolumic relaxation, ventricular filling and PV-loop derived myocardial stiffness. 3 phases of ventricular filling include: early filling, diastasis, and atrial contraction. Early filling follows AV valve opening. The velocity of this inflow is related to the pressure gradient across the AV valve and inversely to the relaxation parameter tau. Most of the pressure gradient results in flow acceleration and the peak velocity occurs at delta p = 0. The ventricular pressure gradually increases with filling, reducing and eventually reversing the AV valve pressure gradient. Blood flow decelerates to the point called diastasis, when both atrial and ventricular pressure are equalized, and there is little flow left. In late diastole, ventricular filling is augmented by atrial contraction which forces more blood into the ventricle. Late diastolic flow depends on atrial mechanical function, preload and afterload. Afterload depends upon LV late diastolic stiffness and pressure. Diastolic dysfunction is relatively common in elderly subjects, occurring in up to 45% over the age of 70.

Key Issues: Normal and abnormal diastolic function is evaluated through early filling, diastasis and atrial contraction. These are demonstrated by echocardiography, MUGA, and MRI. Pathophysiology, including restrictive and constrictive conditions, is presented, along with atrial dysfunction associated with dilatation and atrial fibrillation. New data is presented to demonstrate these principles: MRI diastolic filling curves on 139 volunteer subjects age 65-90 demonstrates peak filling rates (EDV/sec) of < 1.5 in 5 (4%), < 1.6 in 10 (7%), < 1.7 in 18 (13%), < 1.9 in 36 (29%), and < 2 in 47 (34%).

Format: This didactic presentation is organized to: 1. Review diastolic physiology. Clinical scope of diastolic abnormalities. 2. Demonstrate normal trans-mitral flow, volume curves, and tissue Doppler displays. 3. Demonstrate abnormal early and late diastolic function.

Teaching Points: The learning objectives are to: 1. Review the mechanics and pathophysiology of diastolic function. 2. Demonstrate normal and abnormal diastolic function with echocardiography (trans mitral flow, tissue Doppler), MUGA and MRI (volume time curves, trans mitral flow). Attention is focused to the understanding volumetric and flow curves.

E036. Coronary Artery Aneurysms: Etiologies and Imaging Features

Meyers M.Z.; Gilkeson R.C.; Zahka K.; Markowitz A.H.; Sachs P.B.; Radiology, University Hospitals of Cleveland, Cleveland, OH.

Address correspondence to M.Z. Meyers (mariana.meyers{at}yahoo.com)

Background: Multislice CT has enabled excellent visualization of coronary artery pathology. This exhibit demonstrates the imaging features in evaluation of the patient with coronary artery aneurysms.

Key Issues: The accurate diagnosis of coronary artery aneurysms is important in patient management. While traditionally diagnosed with catheter based angiography, MSCT is an effective tool for diagnosis of coronary artery aneurysms. While aneurysmal disease is associated with atherosclerotic disease, we will present a significant variety of patients with coronary artery aneurysms. Coronary artery aneurysms in congenital heart disease, Marfan's, Takaysu's and Kawasaki disease will be presented. Coronary artery graft aneurysms will also be presented. Correlative MRI examples will be presented.

Format: The exhibit will be organized in a didactic format. Multislice imaging techniques in the diagnosis of coronary artery aneurysms will be discussed. The exhibit will be arranged by pathologic classification, with a discussion of etiology and imaging features.

Teaching Points: Identify CT imaging techniques in evaluation of coronary artery aneurysms. Identify imaging features and criteria for coronary artery aneurysms. Understand the range of diagnoses and etiologies in patients with coronary artery aneurysms.

E037. Evaluation of the Coronary Sinus by Computed Tomography (CT) in Patients with Elevated Right Heart Pressures

Isaacs D.L.; Gamst A.; Hazany S.; Stark P.; Mahmud E.; Radiology, University of California San Diego, San Diego, CA.

Address correspondence to S. Hazany (Saman26{at}yahoo.com)

Objective: The coronary sinus (CS) drains the majority of the coronary circulation to the right atrium (RA). It is in direct contact with the RA and may enlarge with ele-vated right heart pressures. The study objectives were to evaluate the ability of CT to identify the CS, measure its normal diameter, and correlate CS diameter with right heart pressure in patients suspected of pulmonary arterial hypertension (PAH).

Materials and Methods: CS diameter was measured 3cm from the ostium in patients with no known right heart disease with chest CT(+IVC, 2.5 mm collimation, no cardiac gating). CS diameter was measured in patients suspected of PAH with CT within 30 days of right heart catheterization. Correlations between CS size and right heart pressures were computed.

Results: The CS was seen on CT in all 60 patients (60.5±17.5 years, 27 (45%) male) with no known right heart disease. Patients had CT for chest pain (25), shortness of breath (21), rule-out pulmonary embolism (9), hypoxia (3), hemoptysis (1), and tachycardia (1). The CS was measurable in 93% (56/60) and measured 7.05±1.90mm (range 4.0-12.1mm). Small size and cardiac motion precluded measurement in 4 patients. We studied 28 patients (56.5±15.5 years, 13 (46%) male) suspected of PAH: the majority had primary PAH or PAH of unknown etiology (39%) or chronic thromboembolic pulmonary disease (32%). The CS measured 9.09±4.00 mm (range 4.5-24.8 mm). RA pressure was 8.46±5.22 mmHg (range 2.0-22.0 mmHg), systolic PA pressure 70.96±26.92 mmHg (range 20-118 mmHg), diastolic PA pressure 28.21±13.48 mmHg (range 6-48 mmHg) and mean PA pressure 43.96±15.46 mmHg (range17-65 mmHg, 2 NAs). CS diameter correlated with RA pressure (r = 0.413, p = 0.030), systolic PA pressure (r = 0.432, p = 0.022), diastolic PA pressure (r = 0.583, p = 0.001), and mean PA pressure (r = 0.538, p = 0.005).

Conclusion: The CS is visualized on CT and measurable with thin-collimation technique. Mean and variability of CS diameter were calculated in patients with no known right heart disease. In patients suspected of PAH, we found a significant correlation between CS diameter and RA and PA pressure. A dilated CS on CT should alert one to possible elevated right heart pressures.

E038. How Will a 64-slice CT Scanner Impact Patient Effective Dose in Cardiac CT?

Grage R.A.; Radiology, Upstate Medical University, Syracuse, NY.

Address correspondence to R.A. Grage (grager{at}upstate.edu)

Objective: To investigate the change in effective dose in cardiac CT by the replacement of a 16-slice CT scanner with a 64-slice CT scanner.

Materials and Methods: We computed CT cardiac effective doses associated with a 16-slice (GE LightSpeed Pro 16) scanner with the corresponding dose on a 64-slice (GE LightSpeed VCT) scanner. Our calculations accounted for differences in scanner output (i.e., weighted computed tomography dose index, CTDIw), mA, scan rotation time, pitch ratio, as well as the availability of mA modulation through the cardiac cycle. The Pro 16 protocol (370 mA; 0.5 s scan time; 0.3 of pitch; no mA modulation) differed markedly from that of the VCT (550 mA; 0.35 s scan time; pitch of 0.22; mA modulation), which makes a direct dose comparison problematic. We adopted a 10 cm scan length, and used scanner output (CTDIw) data to compute nominal values of the Dose Length Product (DLP) for each scanning protocol. DLP data were converted into the corresponding patient effective dose using a standard conversion factor for chest CT examinations (0.008 mSv/mGy-cm).

Results: The Pro 16 protocol resulted in a DLP of 570 mGy-cm, corresponding to a patient effective dose of 4.6 mSv. The VCT DLP and effective dose were 550 mGy-cm and 4.4 mSv, respectively. The close similarity of the resultant patient effective doses occurs because the factors that reduce the VCT doses relative to those on the Pro 16 (i.e., output, mA modulation, scan rotation time) are offset by factors that increase VCT doses (i.e., pitch, mA).

Conclusion: 64-slice CT scanner should improve diagnostic performance because of the availability of 64 simultaneous acquisition channels, and is not expected to increase patient effective dose.

E039. Coronary Artery Bypass Graft Assessment on Sequential Multidetector CT: Variation Based on Graft Type

Hughes K.M.¹; Poston R.²; Jeudy J.¹; Read K.¹; White C.¹; 1. Diagnostic Radiology, University of Maryland Medical Center, Baltimore, MD; 2. Cardiothoracic Surgery, University of Maryland Medical Center, Baltimore, MD.

Address correspondence to K.M. Hughes (kmhmd2003{at}yahoo.com)

Objective: Due to established practice patterns, the saphenous vein graft (SVG) is frequently used for coronary artery bypass (CABG) despite a well-known tendency to develop thrombosis and neointimal hyperplasia. The purpose of this study was to assess the utility of multidetector CT in monitoring these processes during serial follow-up.

Materials and Methods: 13 patients (3 women, 10 men, mean age 66 years, range 47-82 years) underwent ECG-gated MDCT in the immediate post-operative period (3-32 days, mean = 7) and at least ten months later (10-20 months, mean = 15 months). Each CT was acquired on a 16-slice MDCT using ECG-gating (Philips Brilliance) and bolus timing with a field of view centered on the heart. Two thoracic radiologists assessed each pair of scans by consensus. Early and late occlusion was defined as absence of flow along the expected course of a known bypass graft or previously patent vessel documented on the post-operative scan, respectively. Measurement was made using the matched pair of sequential MDCTs of the proximal and distal diameters of both internal mammary and aortic grafts. An unpaired t-test was performed to measure the statistical difference in graft diameter between the two scans.

Results: A total of 39 bypass grafts were assessed: 14 internal mammary artery (IMA), 3 radial, and 22 SVG. Although none of the grafts failed early, follow-up showed 3 occluded grafts (2 SVG, 1 radial). Patent saphenous grafts demonstrated a reduction in average caliber of the proximal (3.8 mm to 2.5 mm) and distal (3.8 mm to 2.6 mm) segments of the grafts (p < 0.01 for both). In contrast, there was no significant change in the diameter of the IMA or radial artery bypass grafts which measured an average 2.1 cm on both serial scans.

Conclusion: ECG-gated MDCT is a useful technique to detect bypass graft occlusion and interval SVG narrowing, likely due to neointimal hyperplasia. As a noninvasive means of monitoring these critical events, MDCT may play a key role in future efforts to improve long-term bypass graft patency.

E040. 16-Detector Row Cardiac CT for Anatomical and Functional Analysis: Assessment of a Biphasic Contrast Injection Protocol using Diluted Contrast Media

Utsunomiya D.^1,2; Awai K.²; Sakamoto T.¹; Nishiharu T.¹; Urata J.¹; Nakaura T.²; Yamashita Y.²; 1. Diagnostic Imaging Center, Saiseikai Kumamoto Hospital, Kumamoto, Kumamoto, Japan; 2. Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Kumamoto, Japan.

Address correspondence to D. Utsunomiya (d-utsunomiya{at}skh.saiseikai.or.jp)

Objective: To determine the optimal contrast injection protocol for anatomical and functional imaging with cardiac 16-row multidetector CT to clearly delineate the endocardial and epicardial contours and coronary vessels.

Materials and Methods: Thirty-eight patients were allocated to three groups based on the contrast protocol: a long-duration biphasic protocol using diluted contrast material in the latter phase (protocol A, 13 patients); a uniphasic protocol with a saline flush (protocol B, 12 patients); a uniphasic protocol without a flush (protocol C, 13 patients). Six regions of interest were drawn within the left ventricle (LV), right ventricle (RV), and interventricular septum along the z-axis. The mean ventricular attenuation, mean difference between maximum and minimum ventricular attenuation, and ventricle-myocardium contrast-to-noise ratio (CNR) were calculated. Attenuation and visualization of the coronary vessels were also compared.

Results: The difference between maximum and minimum RV attenuation was significantly smaller in group A (58.1 HU) than in groups B (179.5 HU) and C (157.0 HU). RV-myocardium CNR was significantly higher in group A (9.0) than in group B (5.5). The mean LV attenuation, difference between maximum and minimum LV attenuation, and LV-myocardium CNR were not significantly different among three groups. In protocol A, both endocardial and epicardial contours were clearly delineated and the cardiac functional analyses were feasible in all cases. The average attenuation and visualization of the coronary vessels were not significantly different among groups. The diagnostic accuracies to detect coronary stenosis were 92%, 93%, and 91%, respectively, for protocols A, B, and C.

Conclusion: The long-duration contrast injection protocol using diluted contrast material is optimal for assessing the coronary vessels and cardiac function.

E041. Multi-detector Row CT of Pulmonary Vein Anatomy prior to Radiofrequency Catheter Ablation for Atrial Fibrillation: Clinical Implication

Lee K.Y.; Kim J.H.; Chung H.H.; Kang E.Y.; Oh Y.W.; Cha S.H.; Radiology, Korea University Hospital, Ansan, Kyoungki-do, South Korea.

Address correspondence to K.Y. Lee (kiylee{at}kumc.or.kr)

Objective: Pulmonary vein (PV) ablation for atrial fibrillation (AF) is currently performed. The purpose of this study was to assess the value of multi-detector row computed tomographic (MDCT) depiction of pulmonary veins that would impact the choice of ablation approach.

Materials and Methods: Thin-section (1.5-mm collimation) contrast material-enhanced CT scans of 117 consecutive patients with atrial fibrillation who were admitted for isolation of pulmonary veins by means of radiofrequency (RF) catheter ablation were obtained over 42-month period. Pulmonary vein anatomy was evaluated based on both the number of venous ostia on each side and drainage patterns of pulmonary veins.

Results: 97 (82.9%) patients had the typical pattern of four PVs with separate ostia. 16 (13.7%) patients had an additional PV, and 4 (3.4%) patients had a left common trunk forming one ostium in the left antrium. 8 patients having an additional PV, RF ablation was applied around the ostium of the additional and other PVs, which were selected on the basis of clinical and electrophysiologic assessment. In these patients, there was no recurrence of atrial fibrillation after RF ablation.

Conclusion: Multiple PV foci are involved in initiation of AF, and elimination of PV muscle conduction is associated with clinical success. MDCT is useful in the identification of anatomic variants of the PVs prior to catheter ablation procedures.

E042. Occlusive Myocardial Infarction: Investigation of Cardiac CT perfusion in a Rat Model

Kim D.; Oh H.; Koh K.; Jeon J.; Byun J.; Radiology, Chosun University Hospital, Gwangju, South Korea.

Address correspondence to D. Kim (kdhoon{at}chosun.ac.kr)

Objective: To exhibit various imaging of CT perfusion and to assess the diagnostic accuracy of 16-slice multidetector computed tomography of the occlusive rat myocardial infarction in the assessment of myocardial perfusion and viability.

Materials and Methods: To evaluate this study, author used 15 rats with thoracotomy and ligation of left anterior descending coronary artery distal to first diagonal artery. We performed a series of enhanced CT in rats that undergo 20 minutes of occlusion followed by 5 minutes. Five rats were also re-examined one week later. Occlusive myocardial infarcted hearts were extirpated. After CT scanning, rats were sacrified for 2,3,5-triphenyltetrazolium chloride (TTC) histochemical staining. A stained slices was compared with CT imaging.

Results: The perfusion defects seen at perfusion CT scan showed larger area than unstained areas at TTC staining. However, the size of the perfusion defect at perfusion CT correlated well with the sizes of unstained areas at TTC staining (r = 0.75).

Conclusion: We could conclude that occlusive myocardial infarction might be accurately detected on CT perfusion scan in many cases in a rat model. Therefore, Cardiac CT perfusion scan may be useful for evaluating occlusive acute myocardial infarct in ER.

E043. Clinical Indications and Management of Coronary Artery Calcification Scoring: What Radiologists Need to Know

Forster B.B.; Andrews G.T.; Isserow S.; Radiology and Cardiology, University of BC Hospital, Vancouver, BC, Canada.

Address correspondence to B.B. Forster (formay{at}telus.net)

Background: Coronary artery disease (CAD) continues to be the number one cause of death in North America. Primary prevention of CAD requires identification of an atrisk population and preferably at-risk individuals, so effective intervention can be implemented. Unfortunately, traditional Framingham risk factors predict only 60–65% of hard cardiac events (HCE) (acute myocardial infarction or sudden cardiac death). There is an obvious need to improve risk prediction, and coronary artery calcification scoring (CACS) has been shown in recent large cohorts to be the best single predictor of HCE. As radiologists increase their involvement in cardiac imaging, the need for understanding the indications for and management of CACS is exemplified, as is an awareness of its relationship with coronary CT angiography.

Key Issues: Most presentations on CACS focus on technical aspects only (for example electron beam vs. multi-detector CT), with which most radiologists are familiar. This exhibit will emphasize the appropriate population to screen for CAD, and provide recommendations for further work-up and management depending on the score.

Format: Didactic format. Organizational structure will be: Background, Utility of CAC scoring in symptomatic patients, Utility of CAC scoring in asymptomatic individuals, Recommendations for further management of patients with positive CACs scores, and Who should be screened. The value of a collaborative approach, between radiologists and cardiologists, in setting up a CAD screening program will be discussed.

Teaching Points: 1. To understand the indications for CACS in symptomatic patients, and the role of coronary CTA in the same cohort. 2. To gain an appreciation for the role of CACS in predicting HCE, with respect to other risk factors, in asymptomatic individuals. 3. To learn specific recommendations for management of patients with positive and negative CAC scores. 4. To understand the ongoing role of CACS in the coronary CTA era.

E044. Novel Therapeutic Options for Treatment of Heart Failure: A Radiological Perspective

Agarwal P.P.¹; Desjardins B.¹; Cascade P.N.¹; Pagani F.D.²; 1. Department of Radiology, Division of Thoracic Radiology, University of Michigan, Ann Arbor, MI; 2. Section of Cardiac Surgery, University of Michigan, Ann Arbor, MI.

Address correspondence to P.P. Agarwal (prachia{at}med.umich.edu)

Background: There have been important recent advances in treatment of heart failure unresponsive to medical therapy. The purpose of this educational exhibit is to familiarize radiologists with these innovative treatment modalities, their potential risks and radiographic appearance.

Key Issues: Multiple options are available for treating advanced heart failure including mechanical cardiac assist devices, surgical procedures, biventricular pacing, gene therapy and autologous cell transplantation. The role of radiology in assessment of these methods will be discussed.

Format: This educational exhibit will be presented in a didactic format covering the principles, complications and radiological appearance of the following techniques: I. Mechanical a. For acute cardiogenic shock: IABP, tandem heart (extracorporeal centrifugal continuous flow pump that withdraws blood from the left atrium and pumps it into femoral arteries), axial flow pumps b. For chronic decompensated heart failure: Extracorporeal devices, intracorporeal devices, new smaller more compact devices (axial flow pumps, centrifugal pumps), total artificial heart II. Surgical reshaping of the dilated heart, to decrease wall stress thereby promoting reverse remodeling: Batista procedure, Dor procedure, Cardiomyoplasty (stimulated skeletal muscle wrapped around the heart to help ventricular performance), Acorn device (mesh-like polyester fabric with bidirectional compliance for end-diastolic ventricular support), Myocor (reshaping the heart to a kind of figure of 8 configuration by means of transventricular struts), mitral valve repair/replacement (to reduce regurgitant volume) III. Biventricular pacing for patients with heart failure and intracardiac conduction delay IV. Emerging techniques, such as gene therapy and autologous cell transplantation (myoblasts and stem cells) to promote cardiac repair.

Teaching Points: We hope to teach radiologists about the mechanisms of action and radiographic appearance of emerging technology for the treatment of heart failure to ensure improved reporting and communication with clinical services.

E045. Pulmonary Arterial Hypertension: Imaging Features and Underlying Etiologies

Benamore R.; Weisbrod G.; Doyle D.; Chung T.; Pereira A.; Paul N.; 1. Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada.

Address correspondence to R. Benamore (rachel.benamore{at}uhn.on.ca)

Background: Pulmonary arterial hypertension (PAH) can be thought of as a group of diseases, characterized by increased pulmonary vascular resistance, which leads to right ventricular failure and premature death. The physiological definition is a mean pulmonary artery pressure above 25 mmHg at rest or 30 mmHg during exercise. Radiologists should be aware of the imaging features of both PAH and its many causes, as in some clinical situations, specific therapy can be offered.

Key Issues: The hallmark of PAH is enlargement of the central vessels, with rapid tapering of the more distal arteries, demonstrated on plain radiographs as enlargement or convexity of the main pulmonary artery, or enlargement of the mid-portion of the right lower lobe pulmonary artery above 17 mm. On CT a diameter of the pulmonary trunk greater than 29 mm has a high positive predictive value for the diagnosis of PAH. The causes of PAH are multiple but can broadly be classified as pre-capillary, capillary and post-capillary in etiology. Specific examples include left to right shunts and Eisenmenger's syndrome, thromboembolic disease, primary pulmonary hypertension, portal hypertension, scleroderma, pulmonary capillary haemangiomatosis, pulmonary veno-occlusive disease, left atrial obstruction and left ventricular dysfunction. Chronic lung disease is a well established cause of PAH, but in certain cases, for example bronchiolitis obliterans, the pulmonary radiological findings can be very subtle and clinical signs of lung disease may be occult. We will aim to demonstrate the imaging features of PAH, both on plain film and CT. We will provide examples of the variety of underlying diseases that can be associated with PAH, as detailed above.

Format: This educational review will adopt a didactic format. The presentation will be structured by pathology into the three broad underlying causes of PAH i.e. pre-capillary, capillary and post capillary, taking into account the categories developed by the World Health Organisation symposium on PAH in 1998. Specific plain film and CT examples of the many underlying causes will be included.

Teaching Points: Plain film and CT appearances of pulmonary hypertension. The variety of underlying diseases that can be detected by CT and its importance in the management of these patients.

E046. Did You Look at the Heart? Cardiac Evaluation on Routine Chest CT

Resnick D.¹; Jeudy J.³; Reede D.¹; Shah R.D.²; 1. Radiology, Long Island College Hospital, Brooklyn, NY; 2. Radiology, North Shore University Hospital, Manhasset, NY; 3. Radiology, University of Maryland Medical Center, Baltimore, MD.

Address correspondence to D. Resnick (resnick11{at}yahoo.com)

Background: Prior to the advent of multi-detector CT, little attention was given to cardiac evaluation besides description of size. Currently, many common cardiac conditions are seen on routine Chest CT, prompting a more careful evaluation of the heart. The goal of the exhibit is to emphasize the importance of adding a cardiac overview to the checklist that the General Radiologist uses in conducting a thorough evaluation of a routine Chest CT.

Key Issues: We reviewed over 2,200 routine Chest CTs at 3 major institutions over 1 year and would like to present a collection of these cases with cardiac pathology confirmed with ECHO and other forms of diagnostic imaging. Cases include: congenitalanomalies, pericardial disease, pulmonary hypertension, valvular insufficiency/stenosis, coronary artery pathology, lipomatous hypertrophy of the interatrial septum, vascular anomalies (venous and arterial), left atrial thrombus, and left ventricular aneurysm. As an adjunct, the module will discuss normal anatomic relationships and structures (i.e., Cardiac Recesses) that may mimic pathology.

Format: An interactive PowerPoint (with hyperlinks) will be the learning environment for the exhibit, allowing users to navigate back and forth between various didactic sections based on personal interests. The exhibit will be organized in sections based on pathology.

Teaching Points: 1. Learn normal cardiac anatomy as depicted on CT 2. Review common cardiac conditions as seen on CT 3. Learn to develop an approach to cardiac evaluation on CT.

E047. Cardiovascular Disorders On Noncontrast Chest CT: Dye Another Day

Vagal A.S.; Meyer C.A.; Shipley R.T.; Radiology, University Hospital, University of Cincinnati, Cincinnati, OH.

Address correspondence to A.S. Vagal (achalavagal{at}yahoo.com)

Background: Chest CT exams are often performed without intravenous contrast. Common reasons to withhold contrast include lack of intravenous access, renal insufficiency and prior contrast reaction. Noncontrast studies are used to detect calcification in lung nodules and lymph nodes, especially in endemic areas of granulomatous disease. Noncontrast chest CT is also being performed for lung cancer screening. Familiarity with the primary and ancillary findings of cardiovascular disorders will assist in diagnosing these abnormalities even without the administration of intravenous contrast.

Key Issues: Cardiovascular abnormalities we will illustrate on noncontrast chest CT fall into three categories: abnormalities of the great veins, great arteries and heart. Venous abnormalities we routinely diagnose without contrast include: great venous thrombosis, SVC obstruction, fibrosing mediastinitis and varices. Pulmonary emboli, aortic dissection and intramural hematoma are arterial processes typically diagnosed at contrast CT however can occasionally be diagnosed without contrast. Cardiac conditions such as pulmonary hypertension/right heart failure, myocardial infarction with fatty metaplasia, arrhythmogenic right ventricular dysplasia and left atrial myxoma are seen without contrast administration and will be illustrated. Primary signs of cardiovascular disorders include high density secondary to organized thrombus, fatty metaplasia and vascular distension. Ancillary findings include localized edema and collateral circulation. Close inspection for primary and ancillary findings permits diagnosis of a wide range of cardiovascular abnormalities on noncontrast CT.

Format: The structure of this educational exhibit will be didactic. We will discuss the subtle primary and ancillary findings on noncontrast chest CT which will direct the radiologist to consider a cardiovascular diagnosis. Examples of the above discussed cardiovascular abnormalities on unenhanced chest CT will be demonstrated.

Teaching Points: 1. Illustrate the range of cardiovascular abnormalities that can be detected on noncontrast chest CT. 2. Describe the primary and ancillary findings that aid in detecting subtle cardiovascular abnormalities on noncontrast exams.

E048. Acquired and Congenital Conditions of the Thoracic Aorta

Kanne J.P.^1,2; Takasugi J.E.²; Done S.L.³; Godwin J.D.²; 1. Radiology, Vancouver General Hospital, Vancouver, BC, Canada; 2. Radiology, University of Washington, Seattle, WA; 3. Radiology, Children's Hospital and Regional Medical Center, Seattle, WA.

Address correspondence to J.P. Kanne (jkanne{at}u.washington.edu)

Background: Abnormalities of the thoracic aorta can present at any age from infancy through old age, and with a variety of symptoms, including dysphagia, pain, asymmetric blood pressure measurements, murmur, hoarseness, chest radiographic abnormalities, myocardial infarction, and sudden death. Congenital defects, including variants of aortic arch anatomy, coarctation, and vascular rings are sometimes recognizable on chest radiographs, although CT and MRI more clearly depict the anomaly and are thus often definitive. Similarly, CT and MRI are advantageous in evaluating the acquired conditions of atherosclerosis, dissection, traumatic injury, and inflammatory processes.

Key Issues: CT and MRI have become the primary methods for imaging the thoracic aorta, with conventional angiography used in selected cases and for therapeutic interventions. However, many abnormalities of the thoracic aorta may initially be detected on the chest radiograph. This exhibit will review the various imaging appearances of aortic anomalies and diseases and discuss the differential diagnosis for specific imaging findings.

Format: This electronic educational exhibit will begin with a review of aortic embryology and follow with discussion and illustration of congenital and acquired conditions. Examples will include radiographs, angiograms, CT, and MR, and the key imaging findings will be highlighted.

Teaching Points: 1. Diseases and anomalies of the thoracic aorta can present at any age. 2. While abnormalities of the thoracic aorta may be first identified on the chest radiograph, CT and MR are the techniques of choice for further characterization. 3. A sound knowledge of aortic embryology is key to understanding the various congenital anomalies of the thoracic aorta.

E049. Comparison of a Biphasic Single Injection 64-slice CT-Angiography Protocol to Current Standard Protocols Used for Evaluation of Aortic and Pulmonary Vasculature

Haidary A.F.1; Bis K.G.1; Vrochliotis T.G.1; Kosuri R.1; Balasubramanian M.1; Ross M.1; Oneil B.1; ONeill W.1; 1. Radiology, Cardiology, Emergency Medicine, and Research Institute, William Beaumont Hospital, Royal Oak, MI.

Address correspondence to A.F. Haidary (afh7{at}yahoo.com)

Objective: To compare enhancement of the pulmonary and aortic vasculature using a biphasic single-injection and single-breath-hold 64-slice CT-angiography (CTA) protocol to our current standard protocols used for pulmonary embolism (PE) and aortic dissection (AD). Materials and Methods: With IRB approval and informed consent, 50 patients with atypical chest pain from the Emergency Department were imaged with a Siemens 64-slice CT scanner after premedication with oral atenolol and/or IV metoprolol. Bolus timing was measured in the mid-ascending aorta with 20 ml contrast (Visipaque) (5 ml/sec followed by a 50 ml saline flush at 5 ml /sec). Thoracic CTA was performed 4–5 seconds after aortic peak density (100 ml Visipaque at 5 ml/sec, followed by 30 ml of Visipaque at 3 ml/sec and saline flush with 50 ml saline at 3 ml/sec) with a caudal-to-cranial acquisition. Retrospective ECG-gating was employed (collimation 0.6 mm, tube rotation time 0.3 sec, table feed/rotation 7.68 mm, tube voltage 120 mV, effective mAs 750–850, pitch 0.2). Pulmonary enhancement was compared to 50 patients who had thoracic CT (PE-protocol) (Siemens 16-slice CT scanner). Aortic enhancement was compared to a total of 49 patients who had thoracic CT (AD-protocol) [n = 25 (10-slice CT scanner) and n = 24 (16-slice CT scanner)].

Results: Mean pulmonary attenuation values [HU±SD (standard deviation)]: 16-slice: LUL (182±72.7), TA (227±67.1), LLLS (209±62.4), RLLS (209±88.5), RM (210±57.5), LM (215±61.9) 64-slice: LUL (299±86.4), TA (327±79.8), LLLS (331±81.3), RLLS (315±84.1), RM (310±73.3), LM (315±74.9) (LUL-Left upper lobe, TA-truncus anterior, LLLS-left lower lobe segmental, RLLS-right lower lobe segmental, LM-left main, RM-right main) This is statistically significant at all segments with a p-value < 0.0001. Mean aortic attenuation values (HU±SD): 10-slice: M (216±47.4), P (220±47.7), D (206±47.5) 16-slice: M (210±55.4), P (220±68.5), D (210±51.3) 64-slice: M (331.6±61.2), P (321.8±58.6), D (347.5±61.0) (M-Mid ascending aorta, P-Proximal descending aorta, D-Distal descending aorta) Mean aortic attenuation is significantly higher for the 64 slice scanner when compared to the 10 and 16 slice scanner at all segments with a p-value < 0.0001.

Conclusion: This biphasic single-injection and single-breath-hold CTA protocol provides statistically significant higher attenuation of aortic and pulmonary vasculature than our current dedicated protocols for PE and AD. It is currently used in patients with atypical chest pain to concomitantly evaluate the coronary arteries.

E050. MRI Detection and Quantitation of Intracardiac Shunts

Colletti P.M.; Radiology, University of Southern California, Los Angeles, CA.

Address correspondence to P.M. Colletti (colletti{at}usc.edu)

Background: Intracardiac shunts including atrial septal defect (ASD), ventricular septal defect (VSD), endocardial cushion defects (ECD), and surgical baffles may be identified, localized, and quantified using CMR methods. Comparison is made with extracardiac shunts PDA.

Key Issues: A. Anatomic considerations 1. Dilated cardiac chambers and vessels 2. Ventricular Hypertrophy B. Physiologic considerations 1. Flow jet identification 2. Increased or decreased flow by cine PC methods 3. Dynamic contrast agent circulation times and dilution C. CMR techniques 1. SSFP cine with volumetry 2. Cine PC flow volume measurements 3. Contrast enhanced MRA and dilution studies

Format: This is an interactive electronic exhibit with quizzes and explanations of the principles of intracardiac shunt imaging and quantitation with magnetic resonance. Organization is by image findings: A. Qualitative image findings 1. Indirect evidence (chamber and vessel dilatation) 2. Direct evidence (defect or flow or contrast jet detection) B. Quantitative evaluation 1. Indirect methods (shortened contrast bolus recirculation times, unequal RV and LV stroke volumes (ASD only), or Qp/Qs > or < 1 by PC flow measurement) 2. Direct methods (transseptal shunt flow measurement).

Teaching Points: Indirect and direct MRI methods for the detection and quantitation of intracardiac shunts are presented in an organized format so that participants can: 1. Use indirect and direct findings to detect ASD, VSD, endocardial cushion defects,and surgical baffles. 2. Use indirect and direct MR methods for the quantification of intracardiac shunts. Results are compared for L-->R shunts, including PDA, and complex conditions, including cyanotic R-->L shunts. Multiphase 3D contrast MRA is valuable for the evaluation of pulmonary vasculature, complex anomalies, and first pass baffle flow. First pass contrast bolus views with valsalva may be useful for the detection of subtle bidirectional ASDs.

E051. Imaging Features of Cardiac Noncompaction on MRI with Delayed Enhancement

Sum W.¹; Chow C.M.²; Wu L.¹; 1. Department of Medical Imaging, St Michael's Hospital, Toronto, ON, Canada; 2. Department of Cardiology, St Michael's Hospital, Toronto, ON, Canada.

Address correspondence to W. Sum (wynnesum{at}hotmail.com)

Background: Cardiac non-compaction (CNC) of the myocardium is a rare disorder caused by an arrest in endomyocardial morphogenesis between weeks 5 to 8 of embryonic life. It is characterized by numerous prominent trabeculations and deep intertrabecular recesses which communicate with the left ventricular cavity. Although they may be asymptomatic at diagnosis, many of these patients may eventually develop clinical manifestations of congestive cardiac failure, cardiac arrhythmias, or systemic embolisation. This condition has traditionally been diagnosed with echocardiography. There are a few small case studies in the literature which have described the imaging features of CNC on non-enhanced magnetic resonance imaging (MRI). However, very little is known regarding the enhancement pattern of CNC. This presentation highlights the imaging characteristics of CNC on cardiac MRI including delayed enhancement and identifies parameters which may help predict disease severity and progression.

Key Issues: Data from a case series performed at our institution will be reviewed and the characteristic features of CNC presented. These will include: wall trabeculations and/or thinning, abnormal wall signal, as well as wall motion abnormalities. There will be an emphasis on delayed enhancement pattern – a sign more commonly associated with myocardial infarction. Useful imaging prognostic parameters will be identified and discussed.

Format: This presentation will review pathogenesis and clinical symptoms as background information for this uncommon disease. This will be followed by a review of MR imaging features of Non-Compaction with different cardiac sequences. Both static morphology and cine clips will be presented to illustrate findings.

Teaching Points: 1. Review pathogenesis and clinical symptoms of this uncommon disease entity 2. To become familiar with the diagnosis and imaging features of cardiac non-compaction on magnetic resonance imaging. 3. To recognize delayed enhancement may be seen in this condition - not to be confused with myocardial infarction, especially in a patient with low clinical suspicion of ischemic heart disease. 4. To discuss the role of MRI in the assessment of severity and prognosis of this condition.

E052. MR Imaging of Cardiomyopathies; Can We Tell Them Apart?

Tseng M.H.¹; Protopapas Z.^1,2; Longe T.³; Flygenring B.³; Johnson T.A.³; Johnson K.J.⁴; Lesser J.³; 1. Radiology, Hospital of Saint Raphael, New Haven, CT; 2. Radiology, Yale School of Medicine, New Haven, CT; 3. Cardiology, Minneapolis Heart Institute Foundation, Minneapolis, MN; 4. MRI, Siemens Medical Solutions USA, Inc., Malvern, PA.

Address correspondence to Z. Protopapas (zenonp{at}optonline.net)

Background: Cardiac MR (CMR) can be a valuable noninvasive tool in the diagnosis and quantitative evaluation of cardiomyopathies. Knowledge of typical CMR features in various cardiomyopathies is important for the their classification and in the clinical management of patients.

Key Issues: The exhibit will focus on the typical CMR features of various cardiomyopathies using CINE and viability sequences. Typical CMR features of dilated, hypertrophic, and restrictive cardiomyopathies will be presented. Hyperenhancement patterns in ischemic and nonischemic cardiomyopathies will be illustrated. The exhibit will emphasize the typical functional and hyperenhancement features used to distinguish between arrhythmogenic right ventricular dysplasia, IHSS, amyloid, and non compaction cardiomyopathy, among others. The importance of using gradient echo images in the diagnosis of hemochromatosis will also be discussed.

Format: Didactic and interactive review organized by pathology.

Teaching Points: To describe and illustrate CMR features (with special emphasis on typical findings seen with CINE and viability sequences) in dilated, hypertrophic, and restrictive cardiomyopathies and to establish a practical approach to the evaluation and diagnosis of these conditions.

E053. CT and MR Imaging of Cardiac Tumors

François C.J.¹; Posniak H.¹; Rigsby C.K.²; Carr J.C.³; McCarthy R.¹; Demos T.C.¹; 1. Radiology, Loyola University Medical Center, Maywood, IL; 2. Radiology, Children's Memorial Hospital, Chicago, IL; 3. Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL.

Address correspondence to C.J. François (cfrancois{at}lumc.edu)

Background: Cardiac neoplasms and non-neoplastic mass-like lesions are uncommon. Of these, metastatic neoplasms occur more commonly than primary tumors. While echocardiography has traditionally been used for the diagnosis and evaluation of cardiac masses, this modality is restricted by small fields of view and, in some cases, an insufficient acoustic window. Magnetic resonance imaging (MRI) and computed tomography (CT), however, can regularly depict detailed cardiac anatomy and pathology as well as the extent of disease. In addition, the effect on cardiac function can be evaluated using multidetector row CT (MDCT) and MRI.

Key Issues: CT and MRI can accurately evaluate the size and extent of cardiac masses along with detailed multiplanar depiction of the lesions and their relationship to cardiac anatomy in order to aid preoperative planning. Tissue and enhancement characteristics of lesions can be used to make a diagnosis or narrow the differential diagnosis. Because these imaging modalities use a larger field-of-view than echocardiography, regional metastases can be detected in cases of malignant disease. In addition, as patients with known malignancies live longer, there is a higher frequency of patients presenting with cardiac metastases. It is important for the radiologist to be able to distinguish neoplastic from non-neoplastic lesions.

Format: This didactic educational exhibit will be organized by pathologic diagnoses. The format will be interactive and include quiz cases. Benign primary cardiac neoplasms, including myxoma, rhabdomyoma, fibroma, and lipoma, will be presented first. These will be followed by primary malignancies, including angiosarcoma, osteosarcoma, and lymphoma, and also metastatic lesions. The third section will present non-neoplastic lesions that are included in the differential diagnosis of cardiac tumors, including thrombus, hypertrophic cardiomyopathy, lipomatous hypertrophy of the interatrial septum, pericardial hematoma, and pericardial cyst.

Teaching Points: The goal of this exhibit is to review salient clinical, pathologic, and imaging characteristics of cardiac masses, including primary benign and malignant neoplasms, cardiac metastases, and non-neoplastic lesions, so that the radiologist will be more aware of the differential diagnosis of these lesions and their diagnostic characteristics.

E054. Radiography of Implantable Cardiac Pacemakers and Defibrillators

Costelloe C.M.; Gladish G.; Murphy W.A.; Rozner M.A.; Diagnostic Imaging, University of Texas MD Anderson Cancer Center, Houston, TX.

Address correspondence to C.M. Costelloe (ccostelloe{at}di.mdacc.tmc.edu)

Background: Cardiac pacemakers or defibrillators can be found in more than two million people across the United States. A wealth of clinically relevant information can be obtained through the careful inspection of these devices and their components on chest radiographs. For example, radiographs can be used to identify manufacturers, aiding clinicians in the proper testing of the devices. Pacemakers and defibrillators imply different clinical connotations and can be easily be distinguished by inspection of the components of the implanted hardware on chest radiographs. Radiologically identifiable malfunctions occur in predictable patterns/locations. Identification of these abnormalities can expedite device repair/replacement and reduce patient morbidity and mortality. Noncardiac battery powered devices in the chest can, prior to close inspection, appear similar to pacemakers or defibrillators. The proper identification of such devices can prevent misunderstandings that may be important in emergency situations.

Key Issues: Readers will be instructed to differentiate between cardiac pacemakers, defibrillators, and other generators on chest radiographs. The individual components of common pacemakers and defibrillators will be reviewed and the clinical relevance of each component explained. The radiographic appearance and etiology of damage to these devices will be discussed.

Format: The exhibit will be interactive. Readers will be able to choose among four main options. One will lead to an interactive discussion of the differences between pacemakers and defibrillators. A second will prompt the reader to choose either pacemakers or defibrillators and then allow them to choose icons pertaining to various components of the device. Choosing a component will lead to its name, function and clinical utility. The third will lead to a discussion of radiographic patterns of device malfunction. The fourth will pertain to noncardiac, battery powered devices in the chest. The discussions will consist of radiographs and photographic images prior to device implantation.

Teaching Points: 1. Radiographic differentiation between cardiac pacemakers, defibrillators and noncardiac generators found in the chest cavity. 2. Radiographic identification of the essential components of pacemakers and defibrillators. 3. Knowledge of the purpose and clinical implication of the components of the devices. 4. Knowledge of the radiographic patterns and clinical implications of device failure.

E055. MRI Evaluation of Arrhythmogenic Right Ventricular Dysplasia: An Illustrative Primer

Kearney K.A.; Pantelic M.V.; Myers D.T.; Diagnostic Radiology and Medical Imaging, Henry Ford Hospital, Detroit, MI.

Address correspondence to K.A. Kearney (kearn84{at}comcast.net)

Background: Arrhythmogenic right ventricular dysplasia (ARVD) is the most common of the group of diseases categorized as Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) by the World Health Organization (WHO). ARVD is an incurable primary myocardial disorder that predominantly affects the right heart, resulting in myocyte apoptosis with fibrofatty or fatty replacement of the normal myocardium and resultant ventricular arrhythmias. This disease has a variable presentation and a significant familial predilection, with sporadic, autosomal-dominant and autosomal-recessive patterns described. This disease often presents in adolescents and young adults and has been implicated in sudden cardiac death among young athletes.

Key Issues: The diagnosis of ARVD can be quite difficult, often requiring a combination of clinical, familial, genetic, electrophysiologic and imaging data. Magnetic resonance imaging has remarkable abilities to depict both the structure and function of the myocardium, and can demonstrate the anatomic, morphologic and wall motion abnormalities seen in ARVD. As a result, cardiac MRI has proven an invaluable tool in the evaluation of patients suspected of ARVD.

Format: The format will be a didactic electronic exhibit in Microsoft PowerPoint format. A concise overview of the pathophysiology and management of ARVD will be followed by a review of the current criteria for its diagnosis, with particular focus on the role played by imaging, specifically MRI. The MR imaging techniques appropriate to the evaluation of ARVD will then be introduced, with attention to how each relates to a specific diagnostic need. Finally, these techniques will be assembled into a comprehensive imaging protocol designed to meet these diagnostic requirements. Didactic material will be complemented with illustrative technical diagrams, as well as static and dynamic (AVI cine) MRI images from clinical cases juxtaposing normal cardiac anatomy and function with the abnormal findings encountered in ARVD.

Teaching Points: • The clinical and pathophysiologic features of ARVD. • The tools that MRI brings to the diagnosis of ARVD and their correct application. • The integration of these MRI techniques into a comprehensive protocol for the evaluation of ARVD. • The interpretation of structural and functional MRI findings in the diagnosis of ARVD.

E056. MRI of the Chest: An Electronic Atlas

Mortezaie A.R.; Colletti P.M.; Palmer S.L.; Department of Radiology, The Keck School of Medicine, University of Southern California, Los Angeles, CA.

Address correspondence to A.R. Mortezaie (mortezai{at}usc.edu)

Background: A wide variety of disease conditions affect the human thorax. These clinical conditions may be associated with specific and non-specific radiographic findings. Chest x-ray (CXR) and computed tomography (CT) are commonly employed to detect and characterize these chest abnormalities. In addition to CXR and CT, magnetic resonance imaging (MRI) can also be valuable in characterizing pathology of the chest. This exhibit offers an atlas of educational chest MRI with correlative images collected over a 20 year period. Current techniques, including dynamic contrast enhancement, MRA, breath hold and real-time imaging are included.

Key Issues: This educational exhibit demonstrates traumatic, congenital, inflammatory, vascular, and neoplastic chest abnormalities. Some of the specific conditions featured include: abscess, arteriovenous malformation, asbestosis, aspergillosis, berylliosis, breast cancer, bronchogenic carcinoma, bronchogenic cyst, bullous emphysema, diaphragmatic hernia, esophageal carcinoma, esophagitis, lymphoma, melanoma, metastatic choreocarcinoma, pericarditis, pulmonary edema, pulmonary emboli, pulmonary sequestration, radiation pneumonitis, sarcoidosis, thyroid carcinoma, and tuberculosis.

Format: This is a didactic presentation emphasizing current technical considerations of chest MRI, normal MRI chest anatomy, and MRI findings of diseases affecting the chest. For organizational purposes, the chest is anatomically divided into the chest wall, pleura, lung parenchyma, hila, esophagus, and cardiovascular system.

Teaching Points: The learning objectives are to: 1. Review the technical considerations and current methods of chest MRI. 2. Review the normal anatomy of the chest as demonstrated by MRI. 3. Demonstrate the MRI characteristics of various chest lesions with clinical presentations and correlative imaging findings.

E057. Apparent Diffusion Coefficient Measurements in Mediastinal Tumors by Diffusion-weighted Single Shot Fast Spin Echo MR Imaging.

Fujisawa H.; Kushihashi T.; Tanaka E.; Usui N.; Inaba M.; Suzuki M.; Ukisu R.; Takenaka H.; Motoya H.; Department of Radiology, Showa University Northern Yokohama Hospital, Kanagawa, Japan.

Address correspondence to H. Fujisawa (hfuji{at}med.showa-u.ac.jp)

Objective: The aim of this study are to evaluate the possibilities of apparent diffusion coefficient (ADC) values by diffusion weighted MR imaging using single shot fast spin echo (SSFSE-DWI) in distinguishing mediastinal solid tumors from cystic tumors and to find a characteristic ADC value in these tumors.

Materials and Methods: Forty patients with mediastinal tumors including 24 solid tumors and 17 cystic tumors (6 thymomas, 1 thymic cancer, 1 thymic carcinoid, 3 germ cell tumors, 2 neurinoma, 7 lymph nodes, 2 esophageal GIST, 1 mucinous carcinoma, 1 malignant lymphoma, 2 cystic lymphangiomas, 3 bronchogenic cysts, 7 thymic cyst, 2 pericardial cyst, and 3 origin unknown cyst) underwent SSFSE-DWI MRI (b = 1,000 sec/mm²) using a 1.5 T MR unit. The apparent diffusion coefficient (ADC) values in the mediastinal tumors of the 41 patients were evaluated. Statistical analysis was performed with ADC values between solid tumors and cystic tumors.

Results: ADC values in solid mediastinal tumors ranged from 0.78 x 10-3 mm²/sec to 1.69 x 10-3 mm²/sec (1.24x10-3 ± 0.30 mm²/sec), while cystic mediastinal mass showed ADC values ranging from 1.89x10-3 mm²/sec to 2.90 x 10-3 mm²/sec, (2.41 x 10-3 ± 0.39 mm²/sec). Solid mediastinal tumors showed significantly lower ADC values compared to cystic mediastinal tumors (p < 0.001). There was no overlap of ADC values between solid and cystic mediastinal tumors. ADC values in thymoma, malignant lymphoma, neurogenic tumor, and lymph node metastasis from small cell lung carcinoma were lower than that of other solid mediastinal tumors.

Conclusion: ADC value with SSFSE-DWI seems to be an effective parameter for distinguishing between solid and cystic mediastinal tumors. Thymoma, malignant lymphoma, neurogenic tumor, and lymph node metastasis from small cell lung carcinoma were showed lower ADC values than that of other solid tumors; therefore it may differentiate these tumors using ADC value. SSFSE-DWI may be usable for mediastinal tumors.

E058. Thoracic Sarcoma: A Pictorial Review

Mourany L.; Attili A.K.; Perniciano P.; Pinsky R.; Strouse P.; Myers J.L.; Kazerooni E.A.; Departments of Radiology and Pathology, University of Michigan Medical Center, Ann Arbor, MI.

Address correspondence to A.K. Attili (aattili{at}umich.edu)

Background: Sarcomas are rare primary thoracic tumors which can originate from the lung parenchyma, tracheobronchial tree, esophagus, mediastinum, arterial/venous structures, heart and chest wall structures, including the breast. Therefore, radiologically thoracic sarcomas have a wide spectrum of manifestations, including lung nodules/masses, central endobronchial tumors, intravascular and chest wall masses. Sarcomas are classified according to their histological features and location of origin. Angiosarcoma, leiomyosarcoma, rhabdomyosarcoma and mesothelioma (sarcomatoid variant) are the most common primary intrathoracic sarcomas. Ewing's sarcoma, primitive neuroectodermal tumor, chondrosarcoma, malignant fibrous histiocytoma osteosarcoma, synovial sarcoma and fibrosarcoma usually arise in the chest wall. While cardiac sarcomas are rare, they are the most common primary malignant cardiac tumors, and are usually angiosarcomas arising in the right atrium. Sarcomas of the breast are very rare, the most common being a malignant phylloides tumor. A combination of clinical, anatomic and radiological features can suggest the diagnosis of a thoracic sarcoma. The role of imaging is to define the origin, the relationship to adjacent structures and extent of tumor in the thorax.

Key Issues: This pictorial review will illustrate the spectrum of imaging findings in thoracic sarcomas with histopathological correlation. The role of modern diagnostic imaging methods such as multidetector CT and MRI will be emphasized.

Format: Pictorial Review.

Teaching Points: 1. Recognize the spectrum of radiological features of Thoracic Sarcomas 2. Understand the role of modern imaging techniques particularly Multidetector CT and MRI in defining the origin, extent and relationship of tumor within the thorax

E059. Thymic Epithelial Tumors: Comparison between CT and MR Imaging Findings among Low-Risk Thymomas, High-Risk Thymomas, and Thymic Carcinomas

Sadohara J.¹; Fujimoto K.¹; Muller N.L.²; Kato S.³; Takamori S.⁴; Terasaki H.¹; Ohkuma K.¹; Hayabuchi N.¹; 1. Department of Radiology, Kurume University School of Medicine, Kurume, Fukuoka, Japan; 2. Department of Radiology, Vancouver General Hospital and University of British Columbia, Vancouver, B.C., Canada; 3. Department of Pathology, Kurume University School of Medicine, Kurume, Fukuoka, Japan; 4. Department of Surgery, Kurume University School of Medicine, Kurume, Fukuoka, Japan.

Address correspondence to J. Sadohara (sadojun{at}kumin.ne.jp)

Objective: The purpose of this study was to assess the CT and magnetic resonance (MR) imaging findings of thymic epithelial tumors according to the current World Health Organization