Authors:
S. H. H. Kim, S. H. H. Lee, H. W. K. Lim, J. Y. Na, D. L. Choi; Seoul/KP
DOI:
10.1594/ECR03/C-0114
Methods and Materials
Patient selection We searched the medical record database of our institution for the period from August 1995 to August 2002 for patients with surgically proved acute appendicitis. We obtained a list of 33 consecutive patients of acute ascending retrocecal appendicitis who underwent contrast medium-enhanced abdominal and pelvic CT. There were 27 men and 6 women, ranging from 18 to 84 years old (mean age, 50 years). After obtaining CT examinations, the patients underwent surgical treatment immediately or within 22 days. The operative and pathologic findings were also reviewed. CT examinations All CT examinations were performed with a helical CT scanner (HiSpeed Advantage; General Electric Medical Systems, Milwaukee, Wis, U.S.A.). The upper abdomen from the level of the hepatic dome to the inferior tip of the liver was scanned with a helical mode during a breath-hold (7-mm collimation at a pitch of 1 and 7-mm reconstruction intervals, 120kVp, 200-250 mA). The rest of the abdomen and pelvis were scanned with a clustered data acquisition mode (5-mm thickness and 5-mm intervals). Twenty-one patients were asked to drink oral contrast medium (Gastrografin; Schering, Berlin, Germany) 50-60 minutes before scanning and an additional 300 mL immediately before CT scanning. CT scanning was started 70 seconds after the initiation of intravenous injection of nonionic contrast material iopromide (Ultravist 300 [300 mg Iodine/mL]; Schering, Berlin, Germany). By using a mechanical power injector, 120 mL of contrast material was injected at a rate of 2.5 mL/sec. Image analysis CT images in all patients were reviewed and all conclusions were agreed by the two radiologists for identification and thickness of the inflamed appendix, CT patterns of periappendiceal changes (fat strands, fluid, phlegmon), presence of perforation, location and extent of abscess, fascial thickening and change of adjacent bowel wall, lymphadenopathy, presence of appendicolith, free peritoneal or mural air. Individual appendices were categorized into visualization of the entire appendix, a segment of the appendix, and not identifiable. The diameter of the appendix was measured at the maximal magnification on a 2,000 x 2,000 picture archiving and communication system, or PACS, monitor (GE medical Systems Integrated Imaging Solution, Mt Prospect, III). Periappendicial changes were assessed regarding periappendiceal infiltration. Periappendiceal infiltration was graded as follows: severe, areas of soft-tissue attenuation around the appendix; moderate, pericolic haziness or thick strands; mild, a few thin strands; or absent. When the entire appendix is recognized with disruption of wall or presence of free air densities, or abscess formation with partially or invisible appendix, we diagnosed it as perforated appendicitis. The spreads of inflammatory process into the retroperitoneum were presented as thickening of lateroconal and Gerota's fascia and fat strands in perirenal and pararenal spaces. In comparison to the contralateral side, thickening of lateroconal, Gerota's, and transversalis fasciae was evaluated. Diffuse or focal wall thickening of cecum, terminal ileum and ascending colon was evaluated.