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ABSTRACT |
Wednesday, May 3, 1:30 PM-3:30 PM
Abstracts 186-197
Moderators: Genevieve L. Bennett, MD and Abraham Dachman, MD
1:30 PM
186. Staging Accuracy of Multi-Detector Row CT for Extrahepatic Bile Duct Carcinoma
Park M.S.*; Diagnostic Radiology, Severance Hospital, Seoul, South Korea.
Address correspondence to M.S. Park (radpms{at}yumc.yonsei.ac.kr)
Objective: This study sought to evaluate the accuracy of multi-detector computed tomography (MDCT) for preoperative staging of extrahepatic bile duct (EHD) carcinoma and to assess the value of coronal reformations from isotropic voxels.
Materials and Methods: Thirty patients with surgically-proven EHD cancer underwent dynamic MDCT with multiplanar reformation (MPR). Two experienced radiologists independently evaluated contrast-enhanced dynamic transverse CT images and combined transverse and MPR images. TNM staging and the upper and lower margins of tumors were assessed and correlated with pathologic findings of surgical specimen.
Results: All of primary tumors were detected by transverse and combined CT imaging (100%). Overall accuracy of the T staging was 73% (22 of 30) with transverse and 77% (23 of 30) with combined CT imaging (p > 0.05). The accuracy of N staging was 57% (17 of 30) with transverse and 63% (19 of 30) with combined CT imaging (p > 0.05). The accuracy of M staging was 97% (29 of 30) with both transverse and combined CT imaging. Upper margin accuracy was 97% (29 of 30) for transverse and 100% for combined CT imaging (p > 0.05), while that of the lower margin was 90% (27 of 30) for transverse and 93% (28 of 30) for combined CT imaging (p > 0.05).
Conclusion: MDCT was sufficiently accurate for evaluating of upper and lower tumor margins, but not T or N staging. The addition of MPR images did not improve the accuracy for staging of EHD cancer.
187. MR Cholangiography in Patients Post Cholecystectomy: Does the Presence of Surgical Metallic Clips Preclude Patients from Ultra High-field 3 Tesla Abdominal MR Imaging?
Merkle E.M.1*; Dale B.M.2; Paulson E.K.1; Thomas J.1; 1. Radiology, Duke University, Durham, NC; 2. Research and Development, Siemens Medical Solutions, Malvern, PA.
Address correspondence to E.M. Merkle (elmar.merkle{at}duke.edu)
Objective: To evaluate whether surgical clips from prior cholecystectomy impair image quality during MR cholangiography (MRC) at 3 tesla [T] in comparison to standard 1.5T MRC.
Materials and Methods: Seven surgical clips were embedded in a gel phantom and positioned at predefined distances from a fluid-filled tube designed to simulate the common bile duct. In vitro MR imaging protocol included dual echo T1-w GRE, RARE, HASTE, and 3D TSE T2-w sequences on a 1.5 T and a 3 T MR system. Within each magnet class, the maximum clip distance was noted where susceptibility artifacts obscured the fluid-filled tube. Susceptibility artifact size was also calculated for each sequence within each magnet class. In vivo analysis included two separate groups of 21 patients each with a history of cholecystectomy who underwent MRC at either 1.5T or 3T. Presence of susceptibility artifacts was noted for each sequence. In addition, MRC image quality was graded with specific emphasis on whether image quality was impaired by susceptibility artifacts.
Results: In vitro, mean area of susceptibility artifacts was 104 mm2 on the 3 T MR system and 75 mm2 on the 1.5 T MR system. While surgical clips within a 2 mm range impaired visualization of the fluid-filled tube on 1.5 T imaging, this range increased to 4mm on 3 T MR imaging. In vivo, MRC image quality was impaired by susceptibility artifacts in three of 21 cases at 3T and in two of 21 cases at 1.5T by obscuring adjacent biliary ductal branches.
Conclusion: Susceptibility artifacts from surgical clips are larger with ultra-high field 3 T MR imaging than on standard 1.5 T MR imaging., Adjacent biliary ductal branches, however, will not be obscured substantially more often by these susceptibility artifacts at ultra high-field 3T MR imaging, and therefore, patients with a history of prior cholecystectomy should not be withheld from ultra high-field 3T MRC.
188. Multi-Detector Row CT of the Pancreas: Effects of Contrast Material Flow Rates and Individualized Scan Delay on Enhancement of the Pancreas and Tumor Contrast
Schueller G.*; Schima W.; Schueller-Weidekamm C.; Weber M.; Prokesch R.; Radiology, Medical University of Vienna, Vienna, Austria.
Address correspondence to G. Schueller (gerd.schueller{at}meduniwien.ac.at)
Objective: Acquisition times in pancreatic CT imaging are considerably decreased with MDCT, affecting the time window for optimal pancreatic phase scanning. Purpose of this study was to optimize the pancreatic enhancement and the tumor-to-pancreas contrast in 16-row MDCT by varying the contrast material flow rates, and to investigate the impact of individualized versus fixed delay imaging.
Materials and Methods: Forty patients (21 f, 19 m; mean age, 67.1 years) referred for MDCT because of suspected pancreatic tumor were randomized to receive 150 ml of nonionic contrast (300 mg/ml) at 4 ml/s (n = 21) or 8 ml/s flow rate (n = 19). Patients were dynamically scanned at a single level every 2 s for 66 s post IV administration. Contrast enhancement of pancreas and tumors was measured by circular ROIs.
Results: At 8 ml/s flow rate, peak contrast enhancement in the pancreas was observed significantly earlier (28.9 ± 3.4 s vs. 48.6 ± 3.5 s, p < 0.05) and was significantly higher (119.9 ± 29.2 HU vs. 94.5 ± 39.1 HU, p < 0.05). Tumor-to-pancreas contrast > 40 HU was achieved significantly longer in the 8 ml/s flow rate group (26.4 ± 11.9 s vs. 8.6 ± 8.3 s., p < 0.05). At 8 ml/s flow rate, an individualized scan delay of 19 s post aortic transit time revealed significantly higher tumor-to-pancreas contrast than fixed scan delay imaging, and tumor conspicuity was better.
Conclusion: In 16-row MDCT scanning, an increased contrast material flow rate of 8 ml/s and an individualized scan delay improve pancreatic enhancement and tumor-to-pancreas contrast compared to flow rates of 4 ml/s and fixed scan delay imaging.
189. To Assess the Diagnostic Performance and Impact on the Workflow of Semi-automated 2D and 3D MIP's from the 16 MDCT Console in Pre-operative Assessment of Pancreatic Malignancies
Singh A.H.1*; Sahani D.V.1; Thayer S.2; Blake M.1; Joshi M.3; Fernandez-del Castillo C.2; 1. Department of Abdominal Imaging, Massachusetts General Hospital, Boston, MA; 2. Department of Surgery, Massachusetts General Hospital, Boston, MA; 3. CT Engineering, GE Healthcare, Belmont, MA.
Address correspondence to A.H. Singh (dranandsingh{at}yahoo.com)
Objective: The advanced 3D images from workstation, which need technological expertise, entail increased post-processing time and are often not readily available for interpretation. We aim to assess the accuracy, feasibility and timely availability of semi-automated 2D and3D MIP's created directly at 16-MDCT console for predicting operability of pancreatic tumors. The acceptability of semi-automated MIP's by surgeons and radiologist was also assessed and compared with advanced 3D images.
Materials and Methods: Thirty patients (32-83 years age group) with pancreatic malignancy underwent dual phase CT scan on a 16-slice MDCT scanner (1.25 and 2.5mm collimations for the pancreatic and portal venous phases respectively). Images were post-processed on advanced 3D workstation to create 3D images of pancreas and its vicinity vasculature. Semi-automated 2Dand 3D MIP's of 5mmand 15mm thickness were then generated retrospectively at the 16-MDCT-console (GE-ADW) in axial, coronal, oblique and rotational planes. Two pancreatic surgeons (S1, S2) and 2 Radiologists (R1, R2), using a predesigned template evaluated the data for Image quality (IQ) and Diagnostic confidence (DC), which were graded on a 5-point scale (1-poor, 3-acceptable / intermediate, 5-excellent). Comparison was made with advanced 3D images with surgery records being the standard of reference.
Results: Semi-automated MIP, s generated from 16 MDCT console showed an overall sensitivity, specificity and accuracy of 97%, 95% and 96% respectively. The positive predictive value and negative predictive value for predicting tumor operability for the radiologists were 90% and 86% respectively, which was concordant with the findings from advanced 3D workstation images. The IQ and DC for semi-automated MIP's were rated as excellent 4.8 and 4.5 (5-point scale) by radiologists and surgeons with excellent inter-observer agreement (kappa=0.89). Average time spent on generation of semi-automated MIP's at console and advanced 3D images was 3.5 minutes and 25 minutes respectively.
Conclusion: Semi-automated 2Dand3D MIP's generated from 16-MDCT scanner console are highly accurate for predicting pancreatic tumor operability and are acceptable to surgeons. They are also simple and quicker to generate and thus will have an impact on the workflow.
190. Pseudomyxoma Peritonei Syndrome: Correlation of MR Findings and Histopathologic Tumor Classification
Low R.N.1*; Barone R.2; Gurney J.1; Muller W.3; 1. Radiology, Sharp Memorial Hospital, San Diego, CA; 2. Surgical Oncology, Sharp Memorial Hospital, San Diego, CA; 3. Pathology, Sharp Memorial Hospital, San Diego, CA.
Address correspondence to R.N. Low (rlow{at}ucsd.edu)
Objective: To determine the accuracy of gadolinium-enhanced MR imaging in predicting histologic tumor classification in patients with mucinous appendiceal neoplasms with intraperitoneal spread. The spectrum of disease of pseudomyxoma peritonei syndrome includes three pathologic categories: 1. Disseminated peritoneal adenomucinosis (DPAM) a benign condition arising from appendiceal adenomas 2. Peritoneal mucinous carcinomatosis (PMCA) which has cytological features of adenocarinoma, and 3. Intermediate tumors.
Materials and Methods: Twenty-four patients with mucinous appendiceal neoplasms underwent preoperative gadolinium-enhanced MR imaging. Two observers independently scored each case for the degree of gadolinium tumor enhancement using a four point scale: 1 = no enhancement, 2 = enhancement less than or equal to liver, 3 = enhancement > liver, 4 = enhancement equal to intravascular gadolinium. Quantitative analysis of gadolinium tumor enhancement was performed by placing an ROI over the tumor, liver, and aorta. Tumor: Liver contrast and Tumor: Intravascular Gadolinium contrast was calculated. A pathologist reviewed surgical specimens and classified each case as DPAM, Intermediate, or PMCA tumors. The results of MR imaging were correlated with histopathologic tumor classification.
Results: Histopathologic exam demonstrated 7 DPAM, 5 intermediate and 12 PMCA tumors. DPAM and intermediate tumors showed less intense gadolinium enhancement than PMCA tumors. Qualitatively DPAM and intermediate tumor showed level 1 or 2 gadolinium enhancement in 12/12 cases for observer 1 and 10/12 cases for observer 2. All 12 PMCA tumors showed enhancement greater than the liver, levels 3 or 4, for both observers. A threshold of level 3 or 4 gadolinium enhancements had 100% sensitivity (24/24), 96% accuracy (46/48), and 92% specificity (22/24) for distinguishing PMCA from DPAM and intermediate tumors. Quantitatively, the Tumor: Liver contrast for DPAM and Intermediate tumors was 0.70 + 0.13 compared to 1.54 + 0.28 for PMCA tumors. Tumor: IV gadolinium contrast was 0.53 + 0.09 for DPAM and intermediate tumors and 1.0 + 0.09 for PMCA tumors.
Conclusion: Delayed gadolinium-enhanced MR imaging can accurately predict histologic tumor classification in patients with mucinous appendiceal neoplasms. PMCA tumors show a greater degree of enhancement with gadolinium than DPAM and intermediate tumors. Accurate preoperative determination of tumor classification can assist in selecting patients for surgical cytoreduction and intraperitoneal chemotherapy.
191. Abdominal MR Imaging at 3T: What is the Ultimate Gain in Signal-to-Noise Ratio?
Schindera S.T.1*; Merkle E.M.1; Dale B.M.2; DeLong D.M.1; Nelson R.C.1; 1. Department of Radiology, Duke University Medical Center, Durham, NC; 2. Siemens Medical Solutions USA, Cary, NC.
Address correspondence to S.T. Schindera (sebastian.schindera{at}duke.edu)
Objective: To calculate the gain in signal-to-noise ratio (SNR) of various human abdominal tissues at 3 Tesla (T) compared to standard 1.5T and to validate this calculation in vivo.
Materials and Methods: The expected gain in SNR at 3T in the liver, pancreas, spleen, and kidney compared to standard 1.5T was approximated theoretically for a T2w HASTE (Half-Fourier Acquisition Single-Shot Turbo-Spin Echo) and a T1w gradient echo in- and opposed-phase sequence. Next, fifteen healthy male volunteers (mean age: 32.4 years) underwent abdominal MR imaging in an alternating fashion within two hours using a 1.5T and 3.0T scanner (Siemens Magnetom Symphony, Siemens Magnetom Trio; Erlangen, Germany). Coronal T2w HASTE images and axial T1w gradient echo in- and opposed-phase images were acquired using the default sequence parameters implemented by the vendor and dedicated circular polarized torso coils. SNR was evaluated for various abdominal tissues (liver, pancreas, spleen and kidney). Theoretically calculated SNR ratios were compared to the in vivo data by calculating the 95% confidence interval. In vivo SNR values and ratios of all four abdominal tissues at 1.5T and 3.0T were statistically analyzed with the paired Student's t-test.
Results: In vivo, SNR values of all four abdominal tissues were significantly higher at 3.0T for all sequences (p < 0.01). The highest overall gain in SNR for all abdominal tissues was achieved with the T2w HASTE sequence ranging from 2.9-fold for renal imaging to 5.0-fold for hepatic imaging. The T1w opposed-phase sequence offered the smallest overall gain in SNR for all four abdominal tissues (range: 1.6-fold to 2.4-fold). The calculated gain in SNR was within the 95% confidence interval of the in vivo data for the HASTE and the in-phase sequence for all four abdominal tissues, but only in the pancreas for opposed-phase imaging.
Conclusion: Ultra-high field abdominal MR imaging at 3.0T offers significantly higher SNR compared to standard 1.5T MR imaging in both T1w and T2w sequences.
192. Alternate Diagnosis in Appendicitis: Look for Adenopathy
Saokar A.1*; Braschi M.1,2; Jantsch M.K.1,2; Mueller P.R.1; Hahn P.F.1; Harisinghani M.G.1,2; 1. Radiology, Massachusetts General Hospital, Boston, MA; 2. Radiology, Center for Molecular Imaging Research, Boston, MA.
Address correspondence to A. Saokar (asaokar{at}partners.org)
Objective: Helical CT plays an important role in the evaluation of patients with right lower quadrant pain and suspected acute appendicitis. A broad range of common and uncommon entities may mimic acute appendicitis both clinically and on CT. Occasionally small ileo-colic nodes may be seen in a setting of appendicitis, large nodes are uncommon. The purpose of this study was to evaluate whether acute appendicitis can be associated with lymph node enlargement on CT.
Materials and Methods: Patients with right lower quadrant pain who underwent CT scanning from Jan 2002 to March 2005 were identified (n = 148). A subset of patients with CT features of acute appendicitis and associated ileo-colic lymph nodes constituted the study group (n = 38; M:F = 22:12; age = 8-73 years; mean 34 years). All patients underwent surgery for suspected acute appendicitis. Two experienced GI radiologists retrospectively reviewed the CT images and recorded the location, size and number of lymph nodes.
Results: Of the examined 38 patients, the final diagnosis was acute appendicitis in 33 patients, appendiceal carcinoma in 2 patients and acute appendicitis with large B-cell lymphoma in 1 patient. Patients with acute appendicitis had subcentimeter-sized lymph nodes ranging in size from 3 to 9 mm in the peri-appendiceal region and in the mesentery. An average of 4 nodes was seen per patient. The 2 patients with appendiceal carcinoma also had nodes in the peri-appendiceal location. In both cases the nodes were larger than 10 mm; the largest node was 26 mm in one and 13 mm in the other patient. The patient with diffuse large B-cell lymphoma had disseminated lymphadenopathy in the abdomen (peripancreatic, para-aortic, retrocrural), pelvis and inguinal regions in addition to CT features of acute appendicitis. This patient had 9 nodes larger than one centimeter, the largest node measuring 14 mm in the para-aortic area.
Conclusion: Patients with acute appendicitis can have small lymph nodes ranging from 3-9 mm in size around the appendix and in the ileo-colic region of the mesentery. Presence of larger nodes (10 mm) or unusual distribution of lymph nodes along with CT features of acute appendicitis should raise suspicion for an alternative or a dual pathology.
193. Ultrasound Diagnosis of Occult Inguinal Hernias in Women
Grant T.H.; Neuschler E.I.*; Gabriel H.; Hartz III W.; Soper N.; Zivin S.B.; Departments of Radiology and Surgery, Northwestern University Feinberg School of Medicine, Chicago, IL.
Objective: Inguinal hernias in women can be a cause of severe groin pain. They commonly mimic musculoskeletal and gynecologic pathology, making them difficult to diagnose. These clinically complicated cases can be equally difficult to diagnose using CT or MR imaging. We present 17 cases of occult inguinal hernias in women detected with ultrasound. We describe the proper scanning technique, and report on the findings.
Materials and Methods: Seventeen women, ages 23 to 59 years, were sent for ultrasound for the evaluation of a possible inguinal hernia. They all had indeterminate clinical presentations that defied definitive diagnosis. Patients were scanned using a standardized technique. A 12 MHz multifrequency transducer was used in all cases. Images were stored on hard copy and with video clips. The inguinal ligament was localized after identifying the pubic tubercle and inferior epigastric artery. The exam was performed with and without Valsalva maneuver in a supine position.
Results: The majority of the women at clinical presentation had deep pelvic pain or groin "ache." Two patients presented with a palpable mass. The ultrasound classification of the hernias was as follows: indirect (2), direct (11), femoral (2), and hydrocele of the canal of Nuch (2). Eleven patients had surgical confirmation while the other six were treated conservatively with expectant elective surgery. Ultrasound findings included an unusually high percentage of direct hernias. Two patients with femoral hernias showed a paradoxical decrease in caliber of the common femoral vein, with Valsalva, presumably due to compression by the hernia.
Conclusion: Occult inguinal hernias in women may have unusual presentations that confound the clinical diagnosis. Ultrasound can be extremely helpful in their diagnosis when done with the proper technique. Our sonographic findings were atypical with a very high percentage of diagnosed direct hernias. This is likely related to the difficulty in detecting direct hernias clinically. In a woman, with groin pain and an indeterminate physical exam, we have found that dynamic ultrasound can accurately diagnose and classify inguinal hernias.
194. Contrast Enhanced Multi-Detector Row CT of Abdomen: Correlation of Enhancement with Body Fat Composition (Work-in-Progress)
Namasivayam S.1*; Kalra M.K.1; Torres W.E.1; Small W.C.1; Saini S.1; 1. Radiology, Emory University Hospital, Altanta, GA.
Address correspondence to S. Namasivayam (snamasi{at}emory.edu)
Objective: A fixed dose of intravenous iodine contrast material for abdominal multi-detector row CT (MDCT) examination, to all the patients will result in patient-to-patient variability in enhancement, and either poor enhancement or inappropriate overdose of contrast material. Body weight has been used in a few studies to optimize contrast material dose. However, body is composed of a poorly perfused fat compartment, and a well perfused non-fat compartment which differ in their contrast material distribution. Thus, the aim of this study is to evaluate the correlation of enhancement of liver, portal vein, and abdominal aorta in abdominal MDCT with body fat measurements: body fat mass (BFM), fat mass index (FMI), lean body mass (LBM), and lean body mass index (LBMI).
Materials and Methods: Institutional Review Board approval was obtained. 34 patients (mean age, 42.9 years; M:F, 7:27) referred for contrast enhanced abdominal MDCT examination were included. Patient's body weight and height were recorded. A bioelectric impedance analyzer was used to record the body fat composition. FMI and LBMI were calculated by the formula mass/height2, using BFM and LBM, respectively. A bolus of 150 mL of 300 mg I/mL contrast material was injected at the rate of 3 mL/second. When enhancement in liver reached a threshold of 50 H, scanning was initiated by a bolus tracking program. Enhancement of liver, portal vein, and abdominal aorta were correlated with BFM, FMI, LBM, and LBMI using a linear regression test.
Results: BFM, FMI, FFM, and FFMI were 37.9 kg ± 24.3, 13.5 kg/m2 ± 8.4, 50.6 kg ± 12.5, and 17.7 kg/m2 ± 3.5, respectively. Enhancement of liver, portal vein, and aorta were 85.7 H ± 36.6, 148.7 H ± 52.6, and 139.7 H ± 52.9, respectively. The total enhancement correlated inversely with BFM and FMI (Pearson's correlation coefficient, r = 0.35-0.67, p = 0.048-0.0001), and directly with LBMI (r = 0.34, p = 0.04). Enhancement of liver correlated inversely with BFM and FMI (r = 0.45-0.63, p = 0.008-0.0001). The aortic and portal vein enhancement correlated inversely with BFM and FMI (r = 0.6-0.71, p = 0.0001). Portal vein enhancement correlated directly with LBMI (r = 0.37, p = 0.03).
Conclusion: Preliminary results show that liver, portal vein, and aortic enhancement correlates with body fat composition. Body fat composition analysis before CT examination can enable prediction of contrast enhancement. Work is under progress with different contrast injection protocols.
195. Low Concentration (300 mg I/ml) or High Concentration (370 mg I/ml) Contrast Media for Routine Abdominal CT Examinations on a 16-slice MDCT: An Analysis of Quality, Cost, and Adverse Reactions
Setty B.N.*; Sahani D.V.; Holalkere N.; Blake M.A.; Mueller P.R.; Abdominal Imaging and Interventional Radiology, Massachusetts General Hospital, Boston, MA.
Address correspondence to B.N. Setty (bsetty{at}partners.org)
Objective: To evaluate the degree of enhancement and image quality of routine abdominal CT examinations on 16 slice MDCT using low and high iodine concentra-tions in contrast medium (CM). To assess the impact on the cost and incidence of adverse reactions with the use of high concentration CM.
Materials and Methods: A total of 80 patients scheduled for a routine abdominal CT examinations were administered non-ionic CM of two strengths: 300 mg I/mL (group A; n = 40) and 370 mg I/mL (group B; n = 40) with a constant amount of Iodine injected per kg body weight (550 mgI/kg). CM was injected using a dual injector at 2-3cc/sec followed by a 30cc saline at 2-3cc/sec using the smart prep technique. The parameters used were 140 kVp, auto mAs (range 75-380), slice thickness 5mm, rotation time 0.5 sec and a pitch of 1. The degree of enhancement was quantified in the portal venous phase by measuring HU values in various organs, aorta and the portal vein. An experienced radiologist performed qualitative assessment of the scans based on the degree of enhancement. The above data was analyzed using unpaired t test for each arterial and venous enhancement and the quality of enhancement. The difference in cost and the incidence of adverse reactions in both the groups were calculated.
Results: The mean enhancement values in group B were significantly greater (p < 0.05) than those in group A. The mean HU and standard deviation in group A and group B were aorta = 137 ± 10, 171± 15, portal vein= 148 ± 12, 175 ± 14, liver parenchyma = 108 ± 8, 122 ± 12, renal parenchyma=160 ± 15, 192 ± 15, spleen= 112 ± 10, 129 ± 8 and pancreas 76 ± 18, 101 ± 9 respectively. The mean average enhancement on a 5-point scale was greater in group B than group A (p < 0.01). Up to 17.6 percent savings in cost was observed with the usage of higher concentration of Iodine with no significant increase in adverse reactions.
Conclusion: Use of higher concentration CM provides a higher degree of contrast enhancement and overall image quality of a routine abdominal CT on a 16-slice MDCT. It also adds to significant cost savings with no increased risk of adverse reactions compared to the low concentration iodinated CM.
196. Sclerosing Mesenteritis: Initial and Follow-up CT Imaging Features
Singh A.K.*; Dharani D.; Gervais D.A.; Radiology, University of Massachusetts, Worcester, MA.
Address correspondence to A.K. Singh (pallaviajay{at}hotmail.com)
Objective: To evaluate the initial CT findings and the changes in the imaging features of sclerosing mesenteritis on serial CT scans. A secondary purpose of this study was to evaluate the utility of obtaining follow-up CT in these patients.
Materials and Methods: 38 patients (mean age, 64 years; 33-86 years) who satisfied the CT diagnosis of sclerosing mesenteritis on contrast enhanced CT were included in this study. On average there were 3.6 (range, 2-9) follow-up CT scans performed over an average of 2.2 years duration in the 38 patients. All patients with recent surgery, acute pancreatitis, superior mesenteric vein thrombosis and free fluid in the abdomen were excluded from the study. The CT findings of sclerosing mesenteritis evaluated by the radiologists included the size, location, margins, lymphadenopathy, fat ring sign, retraction of mesentery and changes on follow-up CT study. The location of the lesion in relation to the superior mesenteric artery branches was also noted.
Results: The CT findings were located in the small bowel mesentery, at least partly below the level of the left renal vein in 37 of the patients. The majority of the lesions were more than 5 cm in size (n = 37) and had a thin incomplete (n = 21), or less commonly, complete peripheral rim (n = 3), most commonly on the anterior aspect. A fat ring halo was present around the mesenteric vessels and/or lymph nodes in 92 % (n = 35) patients. In 58% (n = 22) cases, a jejunal branch of the superior mesenteric artery was seen to cross the left margin of the mesenteric lesion and wrap around the anterior, posterior or both margins. The follow-up CT scan showed progression of the findings, including increased density, development of peripheral rim and/or increase in size in 15 patients. The remaining patients either showed no change (n = 15) or improvement (n = 8) on the repeat CT scans. There was no new malignancy detected in any patients during the period of the study.
Conclusion: The most common appearance of sclerosing mesenteritis on CT is an area of increased mesenteric fat centered on superior mesenteric artery branches with fat ring sign and an incomplete rim. The margin of the mesenteric lesion is partly marked by jejunal branch of the superior mesenteric artery is a useful sign in making a confident diagnosis. There was no malignant conversion in any of the patients and there was no indication to obtain a follow-up CT study.
197. Role of Graded Compression Sonography and Unenhanced Helical CT in Patients with Suspected Acute Appendicitis
Vashisht S.*; Gamanagatti S.; Kapoor A.; Chumber S.; Bal S.; RadioDiagnosis, All India Institute of Medical Sciences, New Delhi, Delhi, India.
Address correspondence to S. Vashisht (sushvash{at}hotmail.com)
Objective: To compare the accuracy of graded compression sonography and helical unenhanced CT in the diagnosis of acute appendicitis.
Materials and Methods: This prospective study comprised of 58 consecutive patients with high clinical suspicion of acute appendicitis. All these patients, after careful clinical assessment and laboratory investigations, were evaluated by graded compression sonography followed by helical unenhanced CT, independently, in order to establish the diagnosis. CT was performed from the L2 vertebral body to the pubic symphysis, and no patients were given oral, rectal, or IV contrast medium. The results were compared with operative findings and clinical follow up.
Results: Out of the 58 patients evaluated, surgical confirmation could be obtained in 52 patients and the remaining 6 patients were managed conservatively. Statistical analysis was based on 52 patients only where surgical confirmation was available. Forty eight of the operated patients had evidence of appendicitis and there were 4 negative patients. Analysis of the data for US and CT, respectively, revealed a sensitivity of 67.34% versus 95.8%, specificity of 100 versus 75%, accuracy of 71.15% versus 90.3%, positive predictive value 100% versus 97.8% and negative predictive value 15.78% versus 60%. Out of the operated patients, 4 patients did not have acute appendicitis and alternative diagnosis was suggested by US and CT in one patient. Of the 6 patients managed conservatively, an alternative diagnosis was reached both by US and CT in two patients.
Conclusion: Unenhanced helical CT is more accurate than US in the diagnosis of suspected acute appendicitis.
* Will present paper
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