Imaging Findings of Intragastric Gallstone and Bouveret's Syndrome

Gallstone ileus is a well-known complication of cholelithiasis, but is relatively rare. Most ectopic gallstones are located in the small bowel; they are rarely found in the stomach and duodenum. We describe the imaging findings of a case of intragastric gallstone, as well as a case in which duodenal obstruction was caused by a large gallstone (Bouveret's syndrome).

Laryngeal Schwannoma: A Case Report

Laryngeal schwannoma is extremely rare. We report the CT and MRI findings of a case occurring in a 65-year-oldwoman, and describe the pathologic correlation. Pre-contrast CT scanning revealed a right supraglot-tic mass witha slightly hyperdense central part and a hypodense peripheral part. Post-contrast CT scanning re-vealed anenhanced hyperdense central part and a rim-like hypodense peripheral part. The density of the pe-ripheral part waslower than that of muscle. The mass showed homogeneous low signal intensity on T1-weighted MR images, homogeneoushigh signal intensity on T2-weighted MR images, and an enhanced high signal intensity central part and a lowsignal intensity peripheral part on gadolinium enhanced T1-weighted images. The enhanced central part correlatedwith Antoni A areas and the peripheral part, showing low attenuation, correlated with Antoni B areas.

Contrast Enhanced Two-Phase Spiral CT of Urinary Bladder

PURPOSE: To determine optimal scan time for the early phase of two-phase spiral CT and to evaluate its usefulness in the detection and assessment of extension of urinary bladder lesions. MATERIALS AND METHODS: In four normal adults, we performed dynamic scanning and obtained time-density curves for internal and external iliac arteries and veins, and the wall of the urinary bladder. Sixty patients with 68 lesions of the urinary bladder or prostate underwent precontrast and two-phase spiral CT scanning. After injection of 100ml of noninonic contrast material, images for the early and delayed phases were obtained at 60 seconds and 5 minutes, respectively. We measured CT H.U. of the wall, the lesion, and lumen of urinary bladder as seen on axial scanning, in each image in which the lesion was best shown. For the detection of bladder lesions and assessment of their extension, precontrast, early-, and delayed phase images were compared. RESULTS: Dynamic study of normal adults showed maximum enhancement of bladder wall between 60 and 100 seconds. The difference of CT H.U. between bladder wall and the lesion was greatest in the early phase. The best detection rate (98.5%) was seen during this phase, and for the detection of bladder lesion, this same phase was superior or equal (66/68,97.1%) to the delayed phase. The precontrast image was also superior or equal (31/68,45.6%) to that of the delayed phase. For the assessment of extension of bladder lesion, the early phase was superior (36/68,52.9%) to the delayed phase, and precontrast image was superior (1/68, 1.5%) to that of the delayed phase. For determining the stage of bladder cancer, the early phase was most accurate if the stages was below B2 or D, while for stage C, the delayed phase was most accurate. CONCLUSION: In two-phase spiral CT scanning, we consider the optimal time for the early phase to be between 60 and 100 seconds after injection of contrast material. For the detection and assessment of extension of urinary bladder lesion, the early phase was superior to the late phase, and for evaluation of the ureter, the delayed phase was useful. The precontrast image was inferior to that of the delayed phase. We suggest that for the detection and assessment of extension of urinary bladder lesion without scanning of the precontrast image, two-phase spiral CT is reliable.

Evaluation of Lateral Margin of Left Lobe of the Liver on CT Scan: Focus on Perisplenic Extension

PURPOSE: The perisplenic extension of the left lobe of the liver can be misinterpreted as a splenic or perisplenic lesion on ultrasonography(US) and computed tomography(CT). The purpose of our study is to classify thelateral margin of the left lobe of the liver into three types and to evaluate the incidence and the relationship between each type and abnormal liver on CT scan. MATERIAL & METHODS: A total of 515 abdominal CT scans frompatients over 15 years old were retrospectively evaluated. Liver contours were divided into three types on the basis of degree of the left lateral extension of left lobe of the liver. Type A was defined as the lateral extension of the left lobe of liver to the medial portion of the stomach, type C as the perisplenic portion, andtype B as between the two types. Each type was further divided into normal and abnormal liver groups based onclinical, CT, surgical & patholigic findings and evaluated on its ratio of normal and abnormal liver, intrahepatic diseases associated with an abnormal liver and statistical significance between a normal and abnormal liver. RESULTS: The incidence of the three types of liver among the 515 patients was 360(69.9%), 121(23.5%) and 34(6.6%) patients in type A, B and C, respectively. Type C showed normal liver in six patients, which was 2.7% of allnormal livers(221/515) and abnormal liver in 28 patients, which was 9.5% of all abnormal livers(294/515). Type Ashowed normal liver in 49.7%, abnormal liver in 50.3% and there was not statistically significant difference between normal and abnormal liver(P>0.05). Type B showed normal liver in 29.8% and abnormal liver in 70.2% ; type C showed normal liver in 17.6%, abnormal liver in 82.4% and there was a statistically significant difference between normal & abnormal liver(P<0.001). The space occupying lesion(SOL) was most common(52.6%) in all theabnormal livers and hepatoma was the most common disease in the SOL(47.2%). In the abnormal type C liver, SOL(58%)and diffuse hepatopathy(32.8%) were most common and hepatoma and liver cirrhosis were the most common diseases,respectively. CONCLUSION: The perisplenic extension of the left lobe of the liver(type C) was seen in 6.6% of abdominal CT scans, and was frequently associated with abnormal liver conditions including SOL. Careful interpretation is needed to differentiate from splenic or perisplenic disease.

Perinatal Hypoxic-lschemic Brain Injury: MR Findings

PURPOSE: To characterize the MR findings of hypoxic-ischemic brain injury and to assess the value of the MR imaging. MATERIALS AND METHODS: SE T1 -, T2-weighted, and IR brain MR images of 44 infants and children with the past history of perinatal hypoxic insults were reviewed. Abnormal brain MR findings of 8 patients with birth history of prematurity and 36 patients with birth history of full-term/posterm including 7 with severe anoxic insult history, were compared in regard to the location and the character of the lesions RESULTS: MRI demonstrated the followings;(1)abnormal signal intensity lesions of subcortical and/or deep cerebral white matter, cortex, and deep gray matter, (2)atrophy of the cerebral white matter, cortex and corpus callosum, with/without ventriculomegaly, and (3)delay in myelination. Periventricular and deep white matter lesions were demonstrated in the prematurity, the deep white matter lesions and/or subcortical white matter lesions in the term/post-term, and deep gray matter lesions in the 7 patients with severe anoxic insults history. CONCLUSION: MR imaging was useful in the diagnosis of the hypoxic-ischemic brain injury, and the white and gray matter lesions were correlated with the time of the injury and the severity of hypoxic insult.