Usefulness of Helical CT in the Diagnosis of Strangulation in Small Bowel Obstruction

PURPOSE: We wished to evaluate the usefulness of helical CT for the diagnosis of strangulation of the dilated small bowels. MATERIALS AND METHODS: The CT scans of 31 patients with small bowel obstruction from various causes were reviewed retrospectively. Thirteen of these patients were confirmed as small bowel strangulation by surgery and pathology. Fourteen patients underwent surgery, but they had no strangulation. Three patients were reduced by using a nasogastric tube and one infant with intussusception was reduced by air reduction. The following CT findings of strangulation were evaluated: reduced bowel wall enhancement by visual assessment and measuring the HU, ascites, thickening of bowel wall, abnormal mesenteric vessel location and whirlpool appearance, and mesenteric venous engorgement. For the precise evaluation of reduced bowel wall enhancement, the HUs were measured by 1 mm2 of ROI, and the differences of HUs between the well enhanced bowel and poorly enhanced bowel were compared. RESULTS: For the diagnosis of strangulation, measurement of HU of the bowel wall could improve the sensitivity from 69% to 100%. The specificity of both methods, by visual assessment and measurement of HU, was 94%. Ascites had a sensitivity of 69% and specificity of 44%. Thickening of bowel wall had a sensitivity of 38% and specificity of 78%. Abnormal mesenteric vessel location and whirlpool appearance had a sensitivity of 38% and specificity of 83%. Mesenteric venous engorgement had a sensitivity of 31% and specificity of 72%. CONCLUSION:Measurement of HU of the bowel wall after contrast enhancement can be a useful method in the differential diagnosis between the strangulated and non-strangulated bowels in patients with small bowel obstruction.

Angioplastia com implante de "stent" na artéria mesentérica superior / Superior mesenteric artery stent following percutaneous transluminal angioplasty

Endovascular techniques have been used to treat arterial stenosis throughout the vascular system. The goal of this work is to report one case of percutaneous transluminal angioplasty with primary stenting of the ostial segment of the superior mesenteric artery for treatment of chronic mesenteric ischemia.

Posttraumatic Intestinal Stenosis: A Case Report

Post-traumatic intestinal stenosis (PIS) is an uncommon sequela of blunt abdominal trauma, in which injury to the mesentery or bowel wall leads to focal ischemic stricture of that segment. We present a case of PIS of the ileum diagnosed on the basis of radiological studies and surgical and pathologic findings in a patient with partial small bowel obstruction occurring five weeks after blunt abdominal trauma.

MR Findings of Bowel Ischemia with Mesenteric Vascular Occlusion: Comparison with Pathologic Findings in a Cat Model

PURPOSE: In order to determine the characteristic MR findings for the early diagnosis of bowel ischemia, we analysed the dynamic enhanced MR images of ischemic bowel induced by mesenteric vascular occlusion in a cat model, and compared the T1-and T2- weighted images (WI) of extracted bowel with the pathologic findings. MATERIALS AND METHODS: According to the ischemic period, twelve cats were assigned to either the normal control group (no ischemic period, n=2), the acute ischemic group (ligation of mesenteric vessels for 3 hours, n=6) or the subacute ischemic group (ligation of mesenteric vessels for 10 hours, n=4). Under general anes-thesia,laparotomy was performed. The ileal artery and vein were ligated, and a columnar surface coil was ap-plied to the expected bowel ischemia. Using a 4.7 T MR scanner, contrast-enhanced T1WI were obtained, after bolus injection of contrast media, at 10, 20, 30, 60, and 90minutes. After formalin fixation of the extracted bowel, T1- and T2WI were obtained, and the specimens were pathologically examined. MR signal intensity at each layer of the bowel wall was measured and compared with the histopathologic findings. RESULTS: On contrast enhanced MR images, the submucosal layer showed most intensive enhancement, fol-lowed-in decreasing order of signal intensity- by muscle and mucosa. Time to peak enhancement of bowel wall was 10-minutes in the normal control group, and 20 and 60minutes in the acute and subacute bowel is-chemia groups, respectively. On T1WI, no significant differences in signal intensity were observed between the ischemic group and the normal control group. On T2WI, the signal intensity of the submucosal layer of the acute ischemic group was significantly higher than that of the normal control or subacute ischemic group, and the signal intensity of the muscular layer of the ischemic group was significantly higher than that of the normal control group. CONCLUSION: Time to peak enhancement of bowel wall was a helpful criterion for assessment of the ischemic period. Analysis of the signal intensity of the bowel wall layer was useful for the early detection of bowel ischemia.

Experimental Study on the Appropriate Embolic Site During Superior Mesenteric Artery Embolization: Using Coiland Gelfoam

PURPOSE: To determine the effective embolic material and appropriate embolic site by comparing bowel changesafter arterial embolization in dogs in which the proximal or distal level of the superior mesenteric artery hadbeen occluded with gelfoam particles or a coil. MATERIAL AND METHODS: Using the coaxial catheter system,superselective arterial embolization was performed at sixteen sites in four dogs. In groups A and B, each site wasoccluded at the proximal or distal marginal artery, respectively, with gelfoam particles and in groups C and D, atthe proximal or distal artery, respectively, with a coi. All dogs were sacrifed one day after the procedure, andgross and microscopic histologic findings were evaluated. RESULT: In all dogs, the procedure was successful. Ingroup B, significant mucosal destruction, lymphocyte proliferation in submucosa and mucosa, and diffuse swellingin all layers of the intestine were found at all sites. The vessel in the submucosal layer was completelyobstructed by red blood cells and gelfoam.At three sites, the intestine showed diffuse ischemic change, and at oneother site, focal ischemic change was observed. In group D, exudation with destruction of mucosa and submucosalhemorrhage occurred at one site, but in groups A and C, intestinal layers were found to be normal. CONCLUSION: Using a coil, superselective arterial embolization was successful, even up to the distal level of the intestinalartery, and the intestine showed no ischemic change. Embolization with gelfoam must be performed carefully at theproximal level, and since it can cause severe intestinal necrosis, must be avoided at the distal level.

Ischemic Colitis Proximal to Obstructing Colonic Carcinoma: Values of CT in Its Detection

PURPOSE: To determine the value of the CT scan in distinguishing an ischemic and a tumoral segment in coloniccarcinoma complicated by proximal bowel ischemia. MATERIALS AND METHODS: CT scans of twenty patients with ischemic colitis proximal to obstructing colonic carcinoma were reviewed retrospectively. The presence of anischemic segment proximal to colonic carcinoma were patho-logically confirmed in 12 patients, and the remaining eight patients showed typical radiologic findings of bowel ischemia on barium enema but on pathologic review showed only colonic carcinoma. CT scans were analyzed for the location, wall thickness, length, and enhancing pattern of both tumoral and ischemic segments in correlation with barium enema or surgico-pathologic results. Theresults of tumor staging shown on CT scan were compared with those of pathologic findings. RESULTS: On CT scan adistinction between ischemic and tumoral segments could be made in 15 patients (75%). The ischemic segments were contiguously proximal to the tumoral segment in 18 patients. In two patients, however, there was an intervening segment of normal bowel between the two segments and this was confirmed by pathology. Maximvm bowel wall thickness ranged from 0.8 to 4.5cm (mean, 2.0cm) in tumoral segments and from 0.6 to 1.5 cm (mean, 1.0cm) in ischemic segments (p<0.05). Tumoral segments were enhanced heterogeneously in 12 patients (60%) and homogeneously in the remaining eight, while ischemic segments were enhanced homogeneously in 14 patients (70%) and heterogeneously insix. Peripheral rim enhancement was seen only in the ischemic segments of four patients (20%). Comparing TNM tumorstaging of the CT scan with that of pathology, CT scan overstaged in two patients (10%) and understaged in one(5%). CONCLUSION: CT is a valuable tool for distinguishing an ischemic from a tumoral segment in patients with ischemic colitis proximal to colonic carcinoma. An understanding of this pathologic entity could reduce the possibility of over or understaging in cases of colonic carcinoma.