AJR F and L Medical Products: Radiation Protection & More
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF)
Right arrow Video
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ryan, R.
Right arrow Articles by Dodd, J. D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ryan, R.
Right arrow Articles by Dodd, J. D.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?
Hotlight (NEW!)
Right arrow
What's Hotlight?
DOI:10.2214/AJR.07.2936
AJR 2008; 190:W294-W303
© American Roentgen Ray Society

Pictorial Essay

Cardiac Valve Disease: Spectrum of Findings on Cardiac 64-MDCT

Ronan Ryan1, Suhny Abbara2, Rivka R. Colen2, Samer Arnous3, Martin Quinn2, Ricardo C. Cury3 and Jonathan D. Dodd1

1 Department of Radiology, Cardiac CT/MRI Program, St. Vincent's University Hospital, Elm Park, 24 Castledawson, Sion Hill, Blackrock, Dublin 4, Ireland.
2 Cardiac MRI-PET-CT Program, Massachusetts General Hospital and Harvard Medical School, Boston, MA.
3 Department of Cardiology, Cardiac CT/MRI Program, St. Vincent's University Hospital, Dublin, Ireland.

Received July 25, 2007; accepted after revision October 6, 2007.

 
Address correspondence to J. D. Dodd (j.dodd{at}st-vincents.ie).

WEB

This is a Web exclusive article.


Abstract
Top
 Abstract
Introduction
 64-MDCT Protocol for Cardiac...
 Mitral Valve
 Aortic Valve
 Tricuspid Valve
 Pulmonary Valve
 Summary
 Conclusion
 References
 
OBJECTIVE. Recent studies have established that cardiac MDCT generates high-quality images of the cardiac valves. Images are acquired during a single breath-hold (inspiration) after the injection of iodinated contrast material (5 mL/s) followed by a saline bolus chaser. Incremental data sets are then reconstructed throughout the R-R interval, and after transfer to a workstation, specialized software combines data sets sequentially to generate cine loops of the heart throughout the cardiac cycle. The purpose of this article is to describe the cardiac MDCT techniques allowing optimal cardiac valve depiction and to illustrate the MDCT appearances of the most important valve diseases.

CONCLUSION. Cardiac MDCT provides an excellent imaging method for illustrating cardiac valve disease. Radiologists should be aware of the various appearances of the common and most important cardiac valve diseases on cardiac MDCT.

Keywords: cardiac imaging • cardiac valve disease • congenital heart disease • coronary artery disease • hemodynamics • MDCT


Introduction
Top
 Abstract
 Introduction
64-MDCT Protocol for Cardiac...
 Mitral Valve
 Aortic Valve
 Tricuspid Valve
 Pulmonary Valve
 Summary
 Conclusion
 References
 
In 2006, the total estimated mortality attributable to cardiac valve disease in the United States was 19,989 deaths [1]. Aortic valve disease accounted for 12,471 deaths, and mitral valve disease for 2,759 deaths, with the remainder divided evenly between diseases of the tricuspid and pulmonary valves. Echocardio graphy and MRI are the principally used imaging techniques for evaluation of the heart [2]. Echocardiography is widely available and is cost-effective, but it is user-operator-dependent and some patients may have poor acoustic windows [3]. Transesophageal echocardiography (TEE) is invasive and has several contraindications (i.e., recent esophageal surgery, recent oral ingestion, un stable cervical spine injuries, unevaluated gastrointestinal bleeding). Cardiac MRI provides high temporal and spatial resolution images of the cardiac valves without ionizing radiation, but it is expensive, is time-consuming, and also has several contra indications (e.g., pacemakers, implantable defibrillators, claustrophobia) [4].

Cardiac MDCT is an emerging technique in noninvasive cardiac imaging [5]. Using data recorded during the cardiac cycle, it is possible to reconstruct multiple incremental data sets throughout the R-R interval [6]. These data sets can be sequentially combined to provide functional imaging in a cine loop that allows evaluation of valvular leaflet morphology and function. Cardiac MDCT is becoming a useful first-line investigation in patients with suspected coronary artery disease (CAD), and as a result, in our experience, many patients are referred without prior echo cardio graphy or cardiac MRI [7]. Thus, it is of increasing importance that radiologists are aware of and can recognize the most important cardiac valve diseases. The purpose of this article is to describe the cardiac MDCT techniques that allow optimal depiction of the cardiac valves and to review the imaging appearances of the most important cardiac valve diseases.


64-MDCT Protocol for Cardiac Valve Evaluation
Top
 Abstract
 Introduction
 64-MDCT Protocol for Cardiac...
Mitral Valve
 Aortic Valve
 Tricuspid Valve
 Pulmonary Valve
 Summary
 Conclusion
 References
 
With 64-MDCT, acquisition parameters include a collimation of 0.6 mm, gantry rotation time of 330 milliseconds, pitch of 0.2, tube voltage of 120 kVp, and tube current of 800 mAs. Images are reconstructed using a small field of view of 12–16 cm to improve spatial resolution, and scanning ranges from the carina to the apex of the heart. In our center, a timing bolus technique is used: 20 mL of contrast material is injected at 5 mL/s with a region of interest placed over the ascending aorta to ascertain the optimum time to peak enhancement. Images are then acquired during a single breath-hold in mid inspiration after the administration of 80–90 mL (depending on the scanning range) of iodinated contrast material (iodixanol [Visipaque 370, GE Healthcare]) at 5 mL/s followed by a 30-mL saline bolus chaser. Images are usually acquired in a craniocaudal direction.

Coronary data sets are reconstructed at between 60% and 70% of the R-R interval because that is generally the phase with the least amount of cardiac motion (Fig. 1A). However, incremental data sets may be reconstructed throughout the R-R interval [8] (Fig. 1B). For cardiac valve evaluation, generally 10 image data sets are reconstructed at 10% intervals. Some centers reconstruct 20 image data sets at 5% increments to further improve temporal resolution, although that protocol requires increased data storage space [8]. Images are reconstructed using 1-mm slices and a 512 x 512 matrix.


Figure 1
View larger version (22K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 1A —ECG-rhythm strip in 52-year-old woman undergoing cardiac MDCT for suspected coronary artery disease. See Figure S1C in supplemental data. For coronary artery evaluation, data sets are usually reconstructed at 60–70% (arrow) of each R-R interval, which is portion of cardiac cycle with least amount of motion. Note pulse of 50–53 beats per minute after β-blocker administration, which improves image quality.

 

Figure 2
View larger version (30K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 1B —ECG-rhythm strip in 52-year-old woman undergoing cardiac MDCT for suspected coronary artery disease. See Figure S1C in supplemental data. For cardiac valve evaluation, multiple data sets (gray bars) are reconstructed in 10% increments, commencing at 0% and ending at 90% of each R-R interval.

 
Perpendicular plane images are superior to parallel plane images for depicting the mitral and tricuspid valve structures for all cardiac phases [8]. For the aortic and pulmonary valves, a cross-sectional image plane perpendicular to the valve cusps provides optimal depiction [9]. After transfer of the data sets to a workstation, specialized software adds data sets together sequentially to generate cine loops of the heart throughout the cardiac cycle, as shown in Figure S1C; this cine CT, and the others mentioned in this article, can be viewed from the information box in the upper right corner of the article at www.ajronline.org. Volume-rendering techni ques may also be used to produce endoluminal views of the valve leaflets and provide high-resolution 3D imaging of the valve apparatus.


Mitral Valve
Top
 Abstract
 Introduction
 64-MDCT Protocol for Cardiac...
 Mitral Valve
Aortic Valve
 Tricuspid Valve
 Pulmonary Valve
 Summary
 Conclusion
 References
 
Normal Findings
The normal mitral valve is a bileaflet structure with an ovoid orifice. The anterior leaflet tends to be more mobile and thicker than the posterior leaflet. The leaflets shows complex movements during the cardiac cycle: Initially, passive opening is followed by rapid, maximal opening with atrial contraction; then, partial closure at end-diastole; and, finally, complete closure from atrial inflow deceleration and ventricular contraction.

Cardiac MDCT provides highly accurate depiction of the normal mitral valve apparatus (Figs. 2A, 2B, and S2C, cine CT at www.ajronline.org). In a recent study of 37 patients with normal mitral valves, image quality was excellent for depicting the mitral valve leaflets, apposition point, commissures, and annulus [8].


Figure 3
View larger version (128K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 2A —Cardiac MDCT in 48-year-old woman being evaluated for suspected coronary artery disease. See Figure S2C, cine CT, in supplemental data. Optimal image plane for normal mitral valve is three-chamber long-axis view. Image at 55% of R-R interval (diastolic phase) shows normal opening of anterior and posterior mitral leaflets (straight arrows) into left ventricle. Attachments to commissures are clearly depicted. Anterolateral and posteromedial papillary muscles (curved arrows) and chordae tendineae (arrowheads) can be clearly seen attached to leaflet tips. Aortic valve is closed as expected.

 

Figure 4
View larger version (136K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 2B —Cardiac MDCT in 48-year-old woman being evaluated for suspected coronary artery disease. See Figure S2C, cine CT, in supplemental data. Image at 5% of R-R interval (systolic phase) shows complete coaptation of leaflets (thin straight arrows). Chordae tendineae (arrowhead) and papillary muscles (curved arrows) remain well visualized in ventricular systole. Aortic valve (thick straight arrow) is open as expected.

 
Mitral Stenosis
Mitral stenosis is a narrowing of the inlet valve of the left ventricle that leads to inadequate diastolic filling. The normal mitral valve orifice measures between 4 and 6 cm2. Narrowing to < 2.5 cm2 impedes the free flow of blood into the left ventricle, and when reduced to < 1 cm2, severe mitral sten osis results [10]. Most cases are secondary to rheumatic heart disease. Less common causes include tumor or thrombus prolapse, infective endocarditis, severe mitral annular calcification (Figs. 3 and S3, cine CT at www.ajronline.org), systemic lupus erythematosus (SLE), rheumatoid arth ritis, and pulmonary carcinoid tumors.


Figure 5
View larger version (122K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 3 —Cardiac MDCT in 68-year-old man being evaluated for suspected coronary artery disease. Three-chamber view shows severe mitral annular calcification involving posterior commissure (curved arrow) impeding normal movement of posterior mitral leaflet, resulting in restricted mitral valve orifice (straight arrow). Note calcification also of aortic cusps. See Figure S3, cine CT, in supplemental data.

 
The prevalence of mitral stenosis from rheumatic fever is declining in the developed world because of antibiotic therapy [11]. Rheumatic heart disease is the most serious complication of rheumatic fever and follows pharyngitis with group A β-hemolytic Streptococcus pyogenes. Approximately 40% of patients develop isolated mitral stenosis. Conversely, rheumatic involvement is present in 99% of stenotic mitral valves excised during mitral valve replacement.

Less common causes of mitral stenosis include tumors, such as left atrial myxoma or thrombus prolapsing into the mitral orifice [12]. Cardiac myxoma is a benign neoplasm and is the most common primary tumor of the heart. Clinical presentation depends on the location and size of the tumor and on its tendency to cause embolism.

Radiologic Assessment
Messika-Zeitoun et al. [13] prospectively compared 2D echocardiography with cardiac MDCT in 29 patients with a spectrum of severity of mitral stenosis. They found that correlation between mitral valve area assessed by cardiac MDCT and echocardiography was excellent (r = 0.88, p < 0.0001), with a small mean absolute difference between the two techniques (0.20 ± 0.17 cm2). Characteristic features of mitral stenosis on cardiac MDCT include thickening and calcification of the leaflets and narrowing of the orifice during diastole (Fig. 4). The left atrium can be enlarged, although often not to the extent seen in mitral regurgitation.


Figure 6
View larger version (140K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 4 —Cardiac MDCT in 68-year-old man being evaluated for atypical chest pain and dyspnea. Multiplanar reformat four-chamber image during ventricular systole shows marked thickening of anterior leaflet of mitral valve (arrow) and severely restricted opening of mitral leaflets.

 
Characteristic features of myxoma on cardiac MDCT include a well-defined spherical or ovoid intracavitary lesion with smooth contours, classically arising in the left atrium from a small pedicle attached to the fossa ovalis of the interatrial septum (Figs. 5A, 5B, and S5C, cine CT at www.ajronline.org). Tumor enhancement is usually homogeneous, although heterogeneous atten uation may reflect hemorrhage, necrosis, or calcification [14].


Figure 7
View larger version (146K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 5A —Cardiac MDCT in 53-year-old man being evaluated for coronary artery disease before tumor resection. See Figure S5C, cine CT, in supplemental data. Multiplanar reformat three-chamber long-axis image shows low-density, oval, well-circumscribed mass (straight arrow) in left atrium. Note characteristic attachment to interatrial septum. Mitral valve leaflets (curved arrow) are closed indicating ventricular systole.

 

Figure 8
View larger version (131K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 5B —Cardiac MDCT in 53-year-old man being evaluated for coronary artery disease before tumor resection. See Figure S5C, cine CT, in supplemental data. Four-chamber view shows prolapse of mass (straight arrow) through mitral valve orifice into left ventricle. Widely open mitral valve leaflets (curved arrows) indicate ventricular diastole.

 
Mitral Regurgitation
Mitral regurgitation occurs from incomplete coaptation of the mitral valve leaflets, allowing backward blood flow into the left atrium. The most common causes include chordae tendineae abnormalities in congenital mitral valve prolapse (MVP); chordae tendineae or papillary muscle rupture from trauma, infection, or myocardial infarction (Figs. 6A, 6B, and S6C, cine CT at www.ajronline.org); myxoid degeneration of the leaflets (Figs. 7 and S7, cine CT at www.ajronline.org); and mitral annular dilatation from left ventricular dilatation (Fig. 8). Less commonly, infective endocarditis may cause perforation of the leaflets.


Figure 9
View larger version (114K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 6A —Cardiac MDCT in 36-year-old man with known mitral valve prolapse who developed sudden-onset severe dyspnea. See Figure S6C, cine CT, in supplemental data. Multiplanar reformat three-chamber long-axis image in ventricular systole shows prolapse of posterior leaflet of mitral valve (arrow) into left atrium.

 

Figure 10
View larger version (103K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 6B —Cardiac MDCT in 36-year-old man with known mitral valve prolapse who developed sudden-onset severe dyspnea. See Figure S6C, cine CT, in supplemental data. Multiplanar reformat three-chamber long-axis image shows no attachment of chordae tendineae (arrow) of posteromedial papillary muscle to posterior leaflet. Findings were confirmed on transesophageal echocardiography (not shown).

 

Figure 11
View larger version (137K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 7 —Cardiac MDCT in 42-year-old woman being evaluated for coronary artery disease before mitral valve surgery for mitral regurgitation. Multiplanar reformat three-chamber long-axis image in ventricular systole shows thickened anterior and posterior leaflets (straight arrows). Posterior leaflet shows slight prolapse into left atrium. Tips of posterior leaflet (curved arrow) do not coapt fully, consistent with mitral regurgitation. See Figure S7, cine CT, in supplemental data.

 

Figure 12
View larger version (142K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 8 —Cardiac MDCT in 68-year-old woman being evaluated for coronary artery disease. Multiplanar reformat three-chamber long-axis image in ventricular systole shows incomplete coaptation of mitral leaflets (straight arrow), consistent with mitral regurgitation. Left ventricle is dilated, and apex (curved arrow) is thin and partly calcified, consistent with chronic myocardial infarction in left anterior descending vascular territory. Appearances are consistent with ischemia-induced mitral annular dilatation.

 
MVP is the most common cause of mitral re gurgitation and occurs when the valve leaflets "billow" backward into the atrium during systole (Figs. 9 and S9, cine CT at www.ajronline.org). The cause of MVP is currently thought to be an underlying defect of connective tissue, supported by the fact that MVP is a prevalent feature in several connective tissue diseases including Marfan syndrome and Ehlers-Danlos syndrome. Deposition of mucoid material within the valve leaflets and associated structures causes myxomatous degeneration. Lengthening of the chordae tendineae is a characteristic feature, and the posterior leaflet is most commonly affected.


Figure 13
View larger version (130K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 9 —Cardiac MDCT in 52-year-old woman being evaluated for coronary artery disease before surgery for mitral valve prolapse. Multiplanar reformat three-chamber long-axis image in ventricular systole shows severe prolapse of posterior mitral leaflet (straight arrow) into left atrium. There is incomplete coaptation of mitral leaflets (curved arrow), consistent with mitral regurgitation. See Figure S9, cine CT, in supplemental data.

 
Radiologic Assessment
In the acute setting, rapid left atrial and ventricular volume overload results in acute severe left heart failure and acute pulmonary edema. In the chronic setting, adaptation of the left atrium and the left ventricle to volume overload allows left atrial and left ventricular dilatation and less severe pulmonary vascular congestion and rarely, if ever, pulmonary hypertension. Alkadhi et al. [15] recently prospectively assessed 19 patients with mitral regurgitation with cardiac MDCT, TEE, and surgery. Cardiac MDCT proved highly accurate in depicting mitral annulus calcification, thickened leaflets, thickened tendinous chords, and leaflet prolapse, but four ruptured chords were missed on MDCT. Planimetric regurgitant orifice area depicted with MDCT correlated well with the severity of mitral regurgitation on TEE and ventriculography (r = 0.81 and 0.92, respectively).


Aortic Valve
Top
 Abstract
 Introduction
 64-MDCT Protocol for Cardiac...
 Mitral Valve
 Aortic Valve
Tricuspid Valve
 Pulmonary Valve
 Summary
 Conclusion
 References
 
Normal Findings
The normal aortic valve is a trileaflet structure. It shows leaflet closure at the midpoint of the aortic root and opening throughout systole to the walls of the aortic root.

Cardiac MDCT provides excellent image quality of the aortic valve apparatus (Figs. 10A, 10B, and S10C, cine CT at www.ajronline.org). Image quality and the widest opening of the cusps depend on the phase of reconstruction. One study found the largest aortic opening occurred at 50 milliseconds after the R wave and that image quality for the aortic valve was optimum in the midsystolic phases (50–150 milliseconds) [16].


Figure 14
View larger version (122K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 10A —Cardiac MDCT in 65-year-old woman being evaluated for coronary artery disease. See Figure S10C, cine CT, in supplemental data. N = noncoronary cusp, R = right coronary cusp, L = left coronary cusp. Multiplanar reformat cross-section image across aortic cusps in ventricular diastole shows normal tricuspid aortic valve apparatus that forms characteristic "Mercedes-Benz" appearance. Cusps show normal complete coaptation in center of valve orifice (arrow).

 

Figure 15
View larger version (128K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 10B —Cardiac MDCT in 65-year-old woman being evaluated for coronary artery disease. See Figure S10C, cine CT, in supplemental data. N = noncoronary cusp, R = right coronary cusp, L = left coronary cusp. Image in ventricular systole shows wide and symmetric opening of all three cusps (arrows).

 
Aortic Stenosis
Aortic stenosis is a narrowing of the aortic valve orifice. The area of a normal aortic valve measures between 3 and 4 cm2. Planimetric measurement of aortic valve area of less than 2 cm2 is clinically significant and less than 0.8 cm2 defines critical stenosis. In young patients, the most common causes are congenital bicuspid aortic valves and rheumatic fever [2]. Rarely but importantly, the ob structive form of hypertrophic cardio myopathy may cause subvalvular aortic steno sis due to systolic anterior motion of the anterior mitral valve leaflet (Figs. 11A, 11B, and S11C, cine CT at www.ajronline.org).


Figure 16
View larger version (117K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 11A —Cardiac MDCT in 44-year-old man being evaluated for atypical chest pain. See Figure S11C, cine CT, in supplemental data. Multiplanar reformat three-chamber long-axis image in ventricular diastole shows asymmetric hypertrophy of left ventricular septal myocardium (arrows).

 

Figure 17
View larger version (115K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 11B —Cardiac MDCT in 44-year-old man being evaluated for atypical chest pain. See Figure S11C, cine CT, in supplemental data. During ventricular systole, there is systolic anterior motion of anterior mitral valve leaflet (curved arrow) with obstruction of left ventricular outflow tract (straight arrow).

 
Bicuspid aortic valve is the most common congenital cardiac malformation and results from complex abnormal cusp formation during valve development. In contrast to the degenerative form of aortic stenosis, aortic stenosis from bicuspid aortic valve presents in young individuals.

In older patients, the most common causes of aortic stenosis include de generative senile calcification of a morpho logically normal valve and infective endo carditis [17]. Degenerative (senile) calcific stenosis is thought to develop secondary to normal "wear and tear" from hemodynamic injury and usually manifests in the seventh to eighth decades (Figs. 12 and S12, cine CT at www.ajronline.org). The degree of calcification is the strongest independent risk factor for dis ease pro gression and an ad verse clinical out come [18]. The severity and location of aortic valve calcification are associated with increased pressure gradient across the aortic valve [19].


Figure 18
View larger version (121K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 12 —Cardiac MDCT in 82-year-old man being evaluated for chest pain. Multiplanar reformat cross-section image across aortic cusps in peak ventricular systole shows degenerative aortic valve disease with thickened calcified cusps (arrows) and restricted opening. See Figure S12, cine CT, in supplemental data.

 
Radiologic Assessment
Bouvier et al. [20] recently studied 30 patients with aortic stenosis. Good agree ment was shown between cardiac MDCT-based aortic valve area and echo cardiography (mean difference on Bland-Altman analysis of –7 mm2). Similarly, Alkadhi et al. [21] evaluated the aortic valve of 20 patients and 20 control subjects using cardiac MDCT and compared the findings with echocardiography. Significant corre lations were found between aortic valve area as depicted on cardiac MDCT and both TEE and transvalvular gradient (r = 0.99, p < 0.001 and 0.74, p < 0.01, respectively). In the absence of the normal three-cusp appearance, a bicuspid aortic valve, which shows two symmetric aortic cusps (Figs. 13A, 13B, and S13C cine CT at www.ajronline.org), can be easily diagnosed on cardiac MDCT. During systole, the open bicuspid aortic leaflets assume an ellipsoid shape.


Figure 19
View larger version (123K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 13A —Cardiac MDCT in 42-year-old man being evaluated for atypical chest pain. See Figure S13C, cine CT, in supplemental data. Multiplanar reformat cross-section image across aortic cusps in ventricular systole shows two cusps (arrows) that do not open; this finding is fully consistent with congenital bicuspid valve and aortic stenosis.

 

Figure 20
View larger version (194K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 13B —Cardiac MDCT in 42-year-old man being evaluated for atypical chest pain. See Figure S13C, cine CT, in supplemental data. Endoluminal view provides higher definition than A of congenital bicuspid valve cusps (arrows).

 
Aortic Regurgitation
Aortic regurgitation is the diastolic flow of blood from the aorta into the left ventricle. Incompetence of the aortic valve or any disturbance of the valvular apparatus results in aortic regurgitation. In acute regurgitation, the left ventricle has no time to adapt, whereas in chronic regurgitation, hypertrophy of the left ventricle allows some adaptation and clinical presentations may be less severe [22]. The most common causes of aortic regurgitation include rheumatic heart disease and infective endo carditis. Less commonly, it may be caused by dilatation of the aortic root due to a connective tissue disease, such as Marfan syndrome, or may be secondary to aortitis; occasionally, it may be caused by aortic dissection when the dissection flap extends proximally down to the valvular annulus.

Infective endocarditis is an infection of the endocardial surface of the heart, most commonly the valves. Many patients have a preexisting underlying valve condition, such as a bicuspid aortic valve (Figs. 14 and S14, cine CT at www.ajronline.org), predisposing to the development of infective endocarditis. Streptococcus viridans is the most common organism. In the acute setting, vegetations can be characteristically depicted on the ventricular side of the aortic valve in the direction of intracardiac blood flow (Figs. 15 and S15, cine CT at www.ajronline.org).


Figure 21
View larger version (148K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 14 —Cardiac MDCT in 41-year-old man with sepsis after ascending aortic graft repair for ascending aortic aneurysm. Multiplanar reformat cross-section image across aortic cusps in ventricular systole shows two cusps (thin straight arrows), consistent with bicuspid aortic valve. Large vegetation (curved arrow) is noted on anterolateral commissure. Infection had eroded through aortic graft resulting in extravasation and perigraft hematoma (thick straight arrows). See Figure S14, cine CT, in supplemental data.

 

Figure 22
View larger version (90K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 15 —Cardiac MDCT in 38-year-old woman being evaluated for coronary artery disease before surgery. Multiplanar reformat three-chamber long-axis image in ventricular diastole shows flail aortic cusp (curved arrow) with complete loss of coaptation. Note small vegetations (thin straight arrows) on two aortic cusps. Small outpouching (thick straight arrow) on aortic wall distal to valve represents surgically proven mycotic aneurysm secondary to infected embolus that impacted in wall. See Figure S15, cine CT, in supplemental data.

 
Radiologic Assessment
Feuchtner et al. [23] found the sensitivity and specificity of cardiac MDCT in detecting aortic regurgitation was 81% and 91%, respectively, when compared with Doppler trans thoracic echocardiography (TTE). MDCT results were better for moderate to severe aortic regurgitation, and MDCT showed a decreased diagnostic accuracy for mild aortic regurgitation and valve calci fications. More recently, Jassal et al. [24] found 64-MDCT to have a sensitivity of 70%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 79% in detecting aortic regurgitation when compared with echocardiography. Anatomic area of the regurgi tant orifice measured by cardiac MDCT correlated well with the TTE-derived vena contracta (r = 0.79, p < 0.001), the ratio of the jet to the left ventricular outflow tract (LVOT) height (r = 0.79, p < 0.001), and the ratio of the jet to the LVOT cross-sectional area (r = 0.75, p < 0.001) [22].


Tricuspid Valve
Top
 Abstract
 Introduction
 64-MDCT Protocol for Cardiac...
 Mitral Valve
 Aortic Valve
 Tricuspid Valve
Pulmonary Valve
 Summary
 Conclusion
 References
 
Normal Findings
The normal tricuspid valve is a trileaflet structure with anterior, septal, and posterior leaflets. The latter two are variable in size and shape.

Tricuspid Regurgitation
Tricuspid regurgitation occurs because of incomplete coaptation of the tricuspid valve leaflets, allowing backward blood flow into the right atrium. Abnormalities of any atrioventricular valve apparatus components (leaflets, chordae, annulus, papillary muscles, or adjacent right ventricular muscle) may cause tricuspid regurgitation. Ebstein's anomaly accounts for the most common congenital cause. The most common acquired conditions include infective endocarditis, floppy valve syndrome, and connective tissue disorders such as Marfan syndrome.

The pathophysiology and morphology of Ebstein's anomaly reflect the embryologic development of the tricuspid valve. The anterior leaflet develops first, arising from the mesenchyme. The posterior and septal leaflets arise through the creation of a diverticulum and resorption of the right ventricular myocardium. Failure or incorrect myocardium resorption results in apical displacement of the septal and posterior tricuspid valve leaflets, leading to atrialization of the inlet of the right ventricle (Figs. 16 and S16, cine CT at www.ajronline.org) [25].


Figure 23
View larger version (105K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 16 —Cardiac MDCT of 53-year-old man with Ebstein's anomaly. Axial image shows atrialization of right ventricle (asterisk). Note apical displacement of septal leaflet (straight arrow) relative to anterior mitral leaflet hinge point. Anterior leaflet is tethered to trabeculae of right ventricular free wall (curved arrow). Note also bowing of interventricular septum into left ventricular cavity secondary to increased right heart pressure. See Figure S16, cine CT, in supplemental data.

 
Radiographic Assessment
The normal tricuspid valve area measures between 3 and 5 cm2. Tricuspid regurgitation may be shown on MDCT by incomplete leaflet coaptation and the presence of reflux of contrast material into the inferior vena cava (IVC) and hepatic veins during the first pass of contrast material [26]. The presence of reflux into the hepatic veins was originally considered highly sensitive and specific for tricuspid regurgitation at low injection rates (i.e., ≤ 3 mL/s), but for current cardiac MDCT protocols, this is not the case because of increased injection rates [27]. Additional described CT abnormalities in Ebstein's anomaly include clockwise rotation of the heart from the enlarged right heart chambers, dilatation of the right atrial appendage, and contrast reflux into enlarged IVC and hepatic veins from tricuspid regurgitation.

Tricuspid Stenosis
Isolated tricuspid stenosis is an uncommon finding. The most common causes include carcinoid heart disease and SLE. Less commonly, a right atrial tumor may cause hemodynamic obstruction (Fig. 17); rarely, constrictive pericarditis may cause functional tricuspid stenosis.


Figure 24
View larger version (116K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 17 —Cardiac MDCT in 42-year-old woman with shortness of breath. Axial 0.75-mm image shows large mass (arrow) in right atrium encroaching onto tricuspid valve orifice and causing obstructive tricuspid stenosis. Mass was surgically confirmed to be atrial myxoma. Note characteristic interatrial septal attachment.

 
Carcinoid tumors are rare neuroendocrine malignancies arising from neural crest amine precursor uptake decarboxylation cells. Approximately 90% of tumors are located in the gastrointestinal system and characteristically metastasize to the liver. In carcinoid syndrome, hepatic metastases overwhelm hepatic metabolism of tumor products, which are then secreted in high doses into the hepatic veins. Such substances cause fibrous endocardial plaques, classically on the tricuspid and pulmonary valves. Cardiac involvement has been recognized in more than half of patients with carcinoid syndrome.

Radiographic Assessment
Cardiac MDCT in carcinoid syndrome shows thickened, retracted tricuspid and pulmonary valves, which can be fixed with little movement during the cardiac cycle [28] (Figs. 18A, 18B, and S18C, cine CT at www.ajronline.org). The right atrium and ventricle may be enlarged, and there may be decreased pulmonary vascularity in severe pulmonic stenosis.


Figure 25
View larger version (125K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 18A — 53-year-old man with known carcinoid syndrome secondary to liver metastases from ileal primary tumor. See Figure S18C, cine CT, in supplemental data. Axial 1-mm image shows thickening of tricuspid leaflets (straight arrow) and chordae tendineae (curved arrow) within right ventricle. Note enlarged right atrium (asterisk).

 

Figure 26
View larger version (157K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 18B — 53-year-old man with known carcinoid syndrome secondary to liver metastases from ileal primary tumor. See Figure S18C, cine CT, in supplemental data. Axial 1-mm image through liver shows multiple hypervascular enhancing lesions (arrowheads), consistent with extensive carcinoid liver metastases.

 

Pulmonary Valve
Top
 Abstract
 Introduction
 64-MDCT Protocol for Cardiac...
 Mitral Valve
 Aortic Valve
 Tricuspid Valve
 Pulmonary Valve
Summary
 Conclusion
 References
 
Normal Findings
The pulmonary valve is a trileaflet structure. It is commonly diseased in patients with congenital disorders but rarely so in those with acquired disease. Cardiac MDCT allows visualization of the leaflets and assessment of dilatation of the pulmonary artery. Trivial pulmonary regurgitation is present in most of the healthy population.

Pulmonary Stenosis
Pulmonic stenosis is most commonly congenital and can be valvular (90%), subvalvular, or peripheral (supravalvular). Valvular pulmonic stenosis is typically an isolated anomaly and comprises 10% of all congenital heart disease. Acquired causes are rare and include carcinoid, rheumatic fever, and infective endocarditis.

Approximately 10–15% of patients with valvular pulmonic stenosis have dysplastic pulmonic valves composed of myxomatous tissue. The failure of normal development of the pulmonic valves at 6–9 weeks' gestation may result in fusion of two cusps in three leaflets that are thickened and partially fused at the commissures or in a single coned-shaped valve (Figs. 19A and 19B).


Figure 27
View larger version (84K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 19A — Cardiac MDCT in 33-year-old man with congenital pulmonary stenosis. Axial 0.75-mm image across pulmonary valve during ventricular diastole shows normal coaptation of valve leaflets (arrow).

 

Figure 28
View larger version (112K):
[in this window]
[in a new window]
[as a PowerPoint slide]
  		Fig. 19B — Cardiac MDCT in 33-year-old man with congenital pulmonary stenosis. During ventricular systole, valve leaflets (arrow) do not open widely and are thickened. Echocardiogram (not shown) confirmed pulmonary stenosis.

 
Radiographic Assessment
The normal trileaflet pulmonic valve area measures 2 cm2/m2 of body surface area (range, 2.5–4.0 cm2). Mild pulmonic stenosis is defined as < 1 cm2 and severe as < 0.5 cm2. Classically, the three leaflets are thin and pliant with partially fused commissures, resulting in a conical or dome-shaped structure with a narrowed central orifice. Poststenotic pulmonary artery dilatation may occur owing to jet effect hemodynamics. Hwang et al. [29] described the chest CT appearance of severe pulmonic stenosis in a 44-year-old man. Images showed a calcified peri cardial ring encompassing the aorta and pulmonary trunk at valve apparatus level causing severe pulmonic stenosis and poststenotic dilatation of the left pulmonary artery. Cardiac MDCT of patients with pulmonic stenosis may depict thickened immobile leaflets and a valvular annulus that is small; the supravalvular area of the pulmonary trunk is often hypoplastic.


Summary
Top
 Abstract
 Introduction
 64-MDCT Protocol for Cardiac...
 Mitral Valve
 Aortic Valve
 Tricuspid Valve
 Pulmonary Valve
 Summary
Conclusion
 References
 
Cardiac MDCT allows accurate assessment of the cardiac valves. Currently, MDCT is not considered a first-line invest igation for cardiac valve evaluation. It is becoming a primary imaging investigation for CAD in certain patient subgroups. Many patients with CAD will have unsuspected underlying valvular disease. Thus, radiologists reading cardiac MDCT should to be able to recognize the most common and most important valve diseases. In addition, patients with aortic stenosis may present with angina and be referred for preoperative assessment for CAD. Cardiac MDCT can provide accurate evaluation of both conditions in a single investigation. Cardiac MDCT may be superior to echocardiography in patients with heavily calcified valves because of the limitations of acoustic shadowing. It may also be a useful alternative in patients with contraindications to TEE.

Several limitations exist with current MDCT scanners. Radiation dose remains a major concern and contraindicates cardiac MDCT in pregnant patients. Optimal images are obtained in patients with sinus rhythm, and because valvular heart disease is commonly associated with arrhythmias, particularly atrial fibrillation, this may lead to suboptimal image quality.


Conclusion
Top
 Abstract
 Introduction
 64-MDCT Protocol for Cardiac...
 Mitral Valve
 Aortic Valve
 Tricuspid Valve
 Pulmonary Valve
 Summary
 Conclusion
References
 
The role of MDCT continues to expand in the evaluation of cardiac disease. Showing structures beyond the coronary arteries, MDCT provides an accurate noninvasive imaging method for valve evaluation. Radiologists should be aware of the most important cardiac valve diseases and their appearance on cardiac MDCT.


References
Top
 Abstract
 Introduction
 64-MDCT Protocol for Cardiac...
 Mitral Valve
 Aortic Valve
 Tricuspid Valve
 Pulmonary Valve
 Summary
 Conclusion
 References
 

  1. Rosamond W, Flegal K, Friday G, et al.; American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Heart disease and stroke statistics—2007 update: a report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Circulation 2007;115 : e69–e171 [Erratum in Circulation 2007; 115:e172][Free Full Text]
  2. Rahimtoola SH. The year in valvular heart disease. J Am Coll Cardiol 2007; 49:361 –374[Free Full Text]
  3. Cicioni C, Di Luzio V, Di Emidio L, et al. Limitations and discrepancies of transthoracic and trans oesophageal echocardiography compared with surgical findings in patients submitted to surgery for complications of infective endocarditis. J Cardiovasc Med (Hagerstown)2006; 7:660 –666[Medline]
  4. Kanal E, Barkovich AJ, Bell C, et al.; ACR Blue Ribbon Panel on MR Safety. ACR guidance document for safe MR practices: 2007.AJR 2007; 188:1447 –1474[Free Full Text]
  5. Hoffmann U, Butler J. MDCT-based coronary angiography: a Rosetta stone for understanding coronary disease? Eur J Radiol2006; 57:329 –330[CrossRef][Medline]
  6. Pannu HK, Jacobs JE, Lai S, Fishman EK. Gated cardiac imaging of the aortic valve on 64-slice multidetector row computed tomography: preliminary observations. J Comput Assist Tomogr2006; 30:443 –446[CrossRef][Medline]
  7. Schroeder S, Kuettner A, Beck T, et al. Usefulness of noninvasive MSCT coronary angiography as first-line imaging technique in patients with chest pain: initial clinical experience. Int J Cardiol2005; 102:469 –475[CrossRef][Medline]
  8. Alkadhi H, Bettex D, Wildermuth S, et al. Dynamic cine imaging of the mitral valve with 16-MDCT: a feasibility study. AJR 2005; 185:636 –646[Abstract/Free Full Text]
  9. Alkadhi H, Desbiolles L, Husmann L, et al. Aortic regurgitation: assessment with 64-section CT. Radiology2007; 245:111 –121[Abstract/Free Full Text]
  10. Enriquez-Sarano M, Seward JB, Bailey KR, Tajik AJ. Effective regurgitant orifice area: a noninvasive Doppler development of an old hemodynamic concept. J Am Coll Cardiol1994; 23:443 –451[Abstract]
  11. Essop MR, Nkomo VT. Rheumatic and nonrheumatic valvular heart disease: epidemi ology, management, and prevention in Africa. Circulation 2005;112 :3584 –3591[Abstract/Free Full Text]
  12. Feuchtner G, Mueller S, Bonatti J, Friedrich G, zur Needen D, Smekal A. Imaging in cardiovascular medicine: prolapsing atrial myxoma—dynamic visualization with multislice computed tomography. Circulation 2004;109 :e165 –e166[Free Full Text]
  13. Messika-Zeitoun D, Serfaty JM, Laissy JP, et al. Assessment of the mitral valve area in patients with mitral stenosis by multislice computed tomography. J Am Coll Cardiol 2006;48 : 411–413[Free Full Text]
  14. Tsuchiya F, Kohno A, Saitoh R, Shigeta A. CT findings of atrial myxoma. Radiology 1984;151 : 139–143[Abstract/Free Full Text]
  15. Alkadhi H, Wildermuth S, Bettex DA, et al. Mitral regurgitation: quantification with 16-detector row CT—initial experience. Radiology 2006;238 : 454–463[CrossRef][Medline]
  16. Abbara S, Pena AJ, Maurovich-Horvat P, et al. Feasibility and optimization of aortic valve planimetry with MDCT. AJR2007; 188:356 –360[Abstract/Free Full Text]
  17. Pomerance A. Pathogenesis of aortic stenosis and its relation to age. Br Heart J 1972;34 : 569–574[Free Full Text]
  18. Otto CM, Lind BK, Kitzman DW, Gersh BJ, Siscovick DS. Association of aortic-valve sclerosis with cardiovascular mortality and morbidity in the elderly. N Engl J Med 1999;341 : 142–147[Abstract/Free Full Text]
  19. Liu F, Coursey CA, Grahame-Clarke C, et al. Aortic valve calcification as an incidental finding at CT of the elderly: severity and location as predictors of aortic stenosis. AJR2006; 186:342 –349[Abstract/Free Full Text]
  20. Bouvier E, Logeart D, Sablavrolles JL, et al. Diagnosis of aortic valvular stenosis by multislice cardiac computed tomography. Eur Heart J 2006; 27:3033 –3038[Abstract/Free Full Text]
  21. Alkadhi H, Wildemuth S, Plass A, et al. Aortic stenosis: comparative evaluation of 16-detector row CT and echocardiography. Radiology 2006;240 : 47–55[Abstract/Free Full Text]
  22. Singh JP, Evans JC, Levy D, et al. Prevalence and clinical determinants of mitral, tricuspid, and aortic regurgitation (the Framingham Heart Study). Am J Cardiol 1999;83 : 897–902 [Erratum in Am J Cardiol 1999; 83:1143][CrossRef][Medline]
  23. Feuchtner GM, Dichtl W, Schachner T, et al. Diagnostic performance of MDCT for detecting aortic valve regurgitation. AJR2006; 186:1676 –1681[Abstract/Free Full Text]
  24. Jassal DS, Shapiro MD, Neilan TG, et al. 64-Slice multidetector computed tomography (MDCT) for detection of aortic regurgitation and quantification of severity. Invest Radiol2007; 42:507 –512[CrossRef][Medline]
  25. Garrett JS, Schiller NB, Botvinick EH, Higgins CB, Lipton MJ. Cine-computed tomography of Ebstein anomaly. J Comput Assist Tomogr 1986; 10:664 –666[Medline]
  26. Groves AM, Win T, Charman SC, Wisbey C, Pepke-Zaba J, Coulden RA. Semi-quantitative assessment of tricuspid regurgitation on contrast-enhanced multidetector CT. Clin Radiol 2004;59 : 715–719[CrossRef][Medline]
  27. Yeh BM, Kurzman P, Foster E, Qayyum A, Joe B, Coakley F. Clinical relevance of retrograde inferior vena cava or hepatic vein opacification during contrast-enhanced CT. AJR 2004;183 :1227 –1232[Abstract/Free Full Text]
  28. Mollet NR, Dymarkowski S, Bogaert J. MRI and CT revealing carcinoid heart disease. Eur Radiol 2003;13 [suppl 6]:L14 –L18[CrossRef]
  29. Hwang YJ, Park CH, Jeon YB, Park KY. Severe pulmonary artery stenosis by a calcified pericardial ring. Eur J Cardiothorac Surg 2006; 29:619 –621[Abstract/Free Full Text]

Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:


Home page
 Postgrad. Med. J.Home page
H A Vargas, E T D Hoey, D Gopalan, S K B Agrawal, N J Screaton, and G S Gulati
Congenital and acquired conditions of the aortic root: multidetector computed tomography features
Postgrad. Med. J., July 1, 2009; 85(1005): 383 - 391.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF)
Right arrow Video
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ryan, R.
Right arrow Articles by Dodd, J. D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ryan, R.
Right arrow Articles by Dodd, J. D.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?
Hotlight (NEW!)
Right arrow
What's Hotlight?

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS