Walter Wiesner

Accuracy of multidetector row computed tomography for the diagnosis of acute bowel ischemia in a non-selected study population

The diagnostic accuracy of multidetector row computed tomography for the prospective diagnosis of acute bowel ischemia in the daily clinical routine was analyzed. Two hundred ninety-one consecutive patients with an acute or subacute abdomen, examined by MDCT over a time period of 5 months, were included in the study. All original CT diagnoses made during the daily routine by radiological generalists were compared to the final diagnoses made by using all available medical information from endoscopies, surgical interventions, autopsies and follow-up. Finally, all CT examinations of patients with an initial CT diagnosis or a final diagnosis of bowel ischemia were reread by a radiologist specialized in abdominal imaging in order to analyze the CT findings and the reasons for initially false negative or false positive CT readings. Twenty-four patients out of 291 (8.2%) had acute bowel ischemia. The age of affected patients ranged from 50 to 94 years (mean age: 75.7 years). Eleven patients were male, and 13 female. Reasons for acute bowel ischemia were: arterio-occlusive (n=11), non-occlusive (n=5), strangulation (n=2), over-distension (n=3) and radiation (n=3). The prospective sensitivity, specificity, PPV and NPV of MDCT for the diagnosis of acute bowel ischemia in the daily routine were 79.17, 98.51, 90.48 and 98.15%. MDCT reaches a similarly high sensitivity in diagnosing acute bowel as angiography. Furthermore, it has the advantage of being helpful in most of its clinical differential diagnoses and of being less invasive with the consecutive possibility of being used earlier in the diagnostic process with all the resulting positive effects on the patients prognosis. Therefore, nowadays MDCT should probably be used as the first step imaging modality of choice in patients with suspected acute bowel ischemia.

Portal-venous gas unrelated to mesenteric ischemia

Abstract. The aim of this study was to report on 8 patients with all different non-ischemic etiologies for portal-venous gas and to discuss this rare entity and its potentially misleading CT findings in context with a review of the literature. The CT examinations of eight patients who presented with intrahepatic portal-venous gas, unrelated to bowel ischemia or infarction, were reviewed and compared with their medical records with special emphasis on the pathogenesis and clinical impact of portal-venous gas caused by non-ischemic conditions. The etiologies for portal-venous gas included: abdominal trauma (n=1); large gastric cancer (n=1); prior gastroscopic biopsy (n=1); prior hemicolectomy (n=1); graft-vs-host reaction (n=1); large paracolic abscess (n=1); mesenteric recurrence of ovarian cancer superinfected with clostridium septicum (n=1); and sepsis with Pseudomonas aeruginosa (n=1). The clinical outcome of all patients was determined by their underlying disease and not negatively influenced by the presence of portal-venous gas. Although the presence of portal-venous gas usually raises the suspicion of bowel ischemia and/or intestinal necrosis, this CT finding may be related to a variety of non-ischemic etiologies and pathogeneses as well. The knowledge about these conditions may help to avoid misinterpretation of CT findings, inappropriate clinical uncertainty and unnecessary surgery in certain cases.

Acute Small Bowel Ischemia: CT Imaging Findings

Small bowel ischemia is a disorder related to a variety of conditions resulting in interruption or reduction of the blood supply of the small intestine. It may present with various clinical and radiologic manifestations, and ranges pathologically from localized transient ischemia to catastrophic necrosis of the intestinal tract. The primary causes of insufficient blood flow to the small intestine are various and include thromboembolism (50% of cases), nonocclusive causes, bowel obstruction, neoplasms, vasculitis, abdominal inflammatory conditions, trauma, chemotherapy, radiation, and corrosive injury. Computed tomography (CT) can demonstrate changes because of ischemic bowel accurately, may be helpful in determining the primary cause of ischemia, and can demonstrate important coexistent findings or complications. However, common CT findings in acute small bowel ischemia are not specific and, therefore, it is often a combination of clinical, laboratory and radiologic signs that may lead to a correct diagnosis. Understanding the pathogenesis of various conditions leading to mesenteric ischemia and being familiar with the spectrum of diagnostic CT signs may help the radiologist recognize ischemic small bowel disease and avoid delayed diagnosis. The aim of this article is to provide a review of the pathogenesis and various causes of acute small bowel ischemia and to demonstrate the contribution of CT in the diagnosis of this complex disease.

Asymptomatic nonspecific serum hyperamylasemia and hyperlipasemia: spectrum of MRCP findings and clinical implications

Abstract We assessed the magnetic resonance cholangiopancreatographic (MRCP) findings in patients with asymptomatic, mild elevations of serum amylase and lipase levels to determine whether there might be a pathoanatomic cause for these laboratory abnormalities. MRCP was performed in 633 consecutive patients. Of these, 54 (8.5%) images were obtained in patients with asymptomatic serum hyperamylasemia and hyperlipasemia. MRCP was performed on a 1.0-T MR system; breath-hold gradient-recall, half-Fourier acquisition, and rapid acquisition with relaxation enhancement sequences were obtained. Findings were verified by follow-up, biopsy, or surgery. One-sided, large-sample z tests were used to compare the incidence of abnormalities between the study and control groups (579 patients). The pancreas appeared abnormal on MRCP in 31 patients (57%), including the pancreas divisum in 10 patients (18.5%). Other findings included morphologic changes compatible with chronic pancreatitis in nine patients (16.6%) and a healed pancreatic laceration, juxtapapillary duodenal diverticulum, papillary sclerosis, intraductal pancreatic lithiasis, and hemochromatosis in one patient each (1.9%). Small cystic lesions (< 1 cm) within the pancreas were seen in 15 patients (27.8%). In eight patients, these were associated with other abnormalities (pancreas divisum in three patients, chronic pancreatitis in four, and pancreatic laceration in one). No malignancy was diagnosed. The incidences of normal examination (p = 0.01), pancreas divisum (p < 0.005), and a small cystic lesion (p = 0.01) as solitary findings in this subgroup of patients were significantly higher when compared with the remainder of the studied population. Investigation of asymptomatic patients with nonspecific hyperamylasemia and hyperlipasemia by means of MRCP yielded pancreatic findings in more than 50% of these patients. Pancreas divisum was found more often than expected in the general population.

Annular pancreas and agenesis of the dorsal pancreas in a patient with polysplenia syndrome

WEB This is a Web exclusive article. olysplenia syndrome is a rare congenital disorder that is characterized by multiple spleens and a broad spectrum of anomalies of the cardiovascular system, bilobed lungs, and malrotation of abdominal organs. Although polysplenia syndrome has been described in association with congenital short pancreas [1] and semiannular pancreas [2], to our knowledge, an annular pancreas and agenesis of the dorsal pancreas associated with polysplenia syndrome have never been reported in the imaging literature. We describe the imaging findings of such a case on barium smallbowel follow-through examination, CT, and MRI. In addition, we discuss the impact of these coexisting pancreatic anomalies on the debate of embryogenesis of annular pancreas.

Normal colonic wall thickness at CT and its relation to colonic distension

Purpose The purpose of this work was to analyze the relation between normal colonic wall thickness at CT and local colonic distension. Method One hundred consecutively acquired patients were included in our study. All patients were asymptomatic regarding their intestine, and their history was always negative for intestinal disease. All CT examinations were performed for other reasons than intestinal disease. Colonic wall thickness at CT was measured digitally in every patient at four locations and set in relation to the local colonic distension. Results The normal colonic wall thickness ranged from 0 to 2 mm in colonic segments with a diameter of ≥4–6 cm, from 0.2 to 2.5 mm in colonic segments with a diameter of 3–4 cm, from 0.3 to 4 mm in colonic segments with a diameter of 2–3 cm, and from 0.5 to 5 mm in colonic segments with a diameter of 1–2 cm. Maximal colonic wall thickness ranged up to 6 and 8 mm in the proximal and distal colon, respectively, if the measured colonic segment showed a luminal width of <1 cm according to contraction. Discussion The normal colonic wall thickness at CT should be regarded as a dynamic value that stays in clear relation to the local colonic distension. In contracted colonic segments, a colonic wall thickness of 6–8 mm may still be normal. On the other hand, a colonic wall measuring 5 and 3 mm should be regarded as thickened if found in colonic segments with a luminal width of >2 and 4 cm, respectively.

Hepatic veno-occlusive disease: MRI findings

We present magnetic resonance imaging findings in a patient with proven hepatic veno-occlusive disease (VOD) caused by the use of “poppers,” a recreational drug used during anal intercourse. Although this report emphasizes the differential magnetic resonance imaging features between VOD and Budd–Chiari syndrome, our case is unique because the VOD was induced by unrelated substances.

Multifocal inflammatory pseudotumor of the liver: dynamic gadolinium-enhanced, ferumoxides-enhanced, and mangafodipir trisodium-enhanced MR imaging findings

Abstract. The MRI characteristics of a multifocal inflammatory pseudotumor of the liver are described. Emphasis is placed on the appearances following intravenous administration of both non-specific and liver-specific MR contrast agents. On post-gadolinium gradient-echo (GE) images an early, intense, and peripheral enhancement was followed by a homogeneous, complete, and persistent enhancement. Lesions showed no uptake following administration of ferumoxides particles nor mangafodipir trisodium, respectively. During follow-up, a peripheral hyperintense rim appeared on precontrast T1-weighted images, a feature not previously described.

Colonic involvement in non-necrotizing acute pancreatitis: correlation of CT findings with the clinical course of affected patients

Abstract. The purpose of this study was to describe CT findings of colonic involvement in acute non-necrotizing pancreatitis and to analyze the correlation between colonic wall thickening at CT and the clinical course of these patients. The CT examinations of 19 consecutive patients with acute non-necrotizing pancreatitis who were not treated with antibiotics initially were analyzed retrospectively. The severity of acute pancreatitis was categorized according to the CT severity index (CTSI) and the presence of colonic wall thickening at the initial CT was compared with the clinical course of all patients. Seven of 11 patients with a CTSI of 4 showed a colonic wall thickening, whereas the remaining patients with a CTSI of 4 (n=4), CTSI of 3 (n=5), and CTSI of 2 (n=3) showed no colonic abnormalities at CT. Patients with colonic wall thickening presented more often with fever, showed higher levels of infectious parameters, needed more often antibiotic therapy, and had more requests for additional CT examinations and CT-guided fluid aspirations as well as a longer duration of hospital stay as compared with patients without colonic wall involvement, even if the latter presented with the same CTSI initially. It is well known that translocation of the colonic flora may significantly influence the clinical course of patients with acute pancreatitis, and our results indicate that patients with acute pancreatitis who present with colonic wall thickening at CT have an increased risk for a complicated clinical course regarding systemic infection.

Cecal gangrene: a rare cause of right-sided inferior abdominal quadrant pain, fever, and leukocytosis

Abstract. We report on a 58-year-old man with known diabetes, congestive heart failure, and need for chronic hemodialysis presenting with right lower abdominal quadrant pain, fever, and leukocytosis. Although initial clinical findings were highly suggestive of acute appendicitis, CT revealed marked circumferential wall thickening of the cecum, which was interpreted as cecal infarction by the radiologist. Intraoperatively, cecal necrosis was confirmed, but the ileocecal valve and, especially, the appendix showed no ischemia. No vascular occlusions were found. Histopathologic analysis of the resected cecum demonstrated isolated transmural cecal necrosis with marked infiltration of the cecal wall by numerous bacteria and neutrophils. We present the CT features and histopathologic findings of isolated cecal gangrene, review the pathogenesis of occlusive and nonocclusive cecal ischemia or infarction, and discuss the role of bacterial superinfection as a potential cofactor in the pathogenesis of isolated cecal necrosis which should be included in the differential diagnosis of right-sided inferior abdominal quadrant pain.