Im Kyung Hwang

Low-dose and standard-dose unenhanced helical computed tomography for the assessment of acute renal colic: prospective comparative study.

Purpose: To compare the efficacy of low-dose and standard-dose computed tomography (CT) for the diagnosis of ureteral stones. Material and Methods: Unenhanced helical CT was performed with both a standard dose (260 mAs, pitch 1.5) and a low dose (50 mAs, pitch 1.5) in 121 patients suspected of having acute renal colic. The two studies were prospectively and independently interpreted for the presence and location of ureteral stones, abnormalities unrelated to stone disease, identification of secondary signs, i.e. hydronephrosis and perinephric stranding, and tissue rim sign. The standard-dose CT images were interpreted by one reviewer and the low-dose CT images independently by two reviewers unaware of the standard-dose CT findings. The findings of the standard and low-dose CT scans were compared with the exact McNemar test. Interobserver agreements were assessed with kappa analysis. The effective radiation doses resulting from two different protocols were calculated by means of commercially available software to which the Monte-Carlo phantom model was given. Results: The sensitivity, specificity, and accuracy of standard-dose CT for detecting ureteral stones were 99%, 93%, and 98%, respectively, whereas for the two reviewers the sensitivity of low-dose CT was 93% and 95%, specificity 86%, and accuracy 92% and 94%. We found no significant differences between standard-dose and low-dose CT in the sensitivity and specificity for diagnosing ureter stones (P>0.05 for both). However, the sensitivity of low-dose CT for detection of 19 stones less than or equal to 2 mm in diameter was 79% and 68%, respectively, for the two reviewers. Low-dose CT was comparable to standard-dose CT in visualizing hydronephrosis and the tissue rim sign. Perinephric stranding was far less clear on low-dose CT. Low-dose CT had the same diagnostic performance as standard-dose CT in diagnosing alternative diseases. Interobserver agreement between the two low-dose CT reviewers in the diagnosis of ureter stones and alternative diseases, the identification of secondary signs, and tissue rim sign were high, with kappa values ranging from 0.769 to 0.968. On standard-dose CT scans, the calculated mean effective radiation dose was 7.30 mSv for males and 10.00 mSv for females. On low-dose CT scans, the calculated mean effective radiation dose was 1.40 mSv for males and 1.97 mSv for females. Conclusion: Compared with standard scans using 260 mAs, low-dose unenhanced helical CT using a reduced tube current of 50 mAs results in a concomitant decrease in the radiation dose of 81%. Although low-dose CT was limited in its ability to depict small-sized calculi less than or equal to 2 mm, it is still comparable to standard-dose CT for the diagnosis of ureter stones and alternative disease.

Perforated ileal duplication cyst with haemorrhagic pseudocyst formation

Duplication cysts of the gastrointestinal tract are rare congenital abnormalities. Ectopic gastric mucosa, which can be found in duplications, may cause peptic ulceration, gastrointestinal bleeding or perforation. We report a 1-year-old boy with a perforated ileal duplication cyst with haemorrhagic pseudocyst formation caused by peptic ulceration of the duplication cyst. It presented a snowman-like appearance consisting of a small, thick-walled, true enteric cyst and a large, thin-walled haemorrhagic pseudocyst on US and CT. It is an unusual manifestation of a duplication cyst, which has not been reported in the English language literature.

Huge biliary cystadenoma mimicking cholecystic lymphangioma in subhepatic space.

Biliary cystadenoma is a rare cystic neoplasm and constitutes only 5% of all intrahepatic cysts of biliary origin. We report a case of a 44-year-old woman with huge biliary cystadenoma in the subhepatic space, mimicking a cholecystic lymphangioma. Findings of various imaging modalities including reconstructed CT image are presented and correlated with surgical and pathologic findings.

Phlegmonous Enteritis in a Patient with Congestive Heart Failure and Colon Cancer

Phlegmonous enteritis is a rare infective inflammatory disease of the intestine, predominantly involving the submucosal layer. It is difficult to diagnose and often fatal. Its association with alcoholism and various liver diseases, although rarely reported, is well documented. We report a case of phlegmonous enteritis in a male patient with congestive heart failure and colon cancer, and describe the ultrasonographic and CT findings.