I. Boulay-Coletta

Increased Unenhanced Bowel-Wall Attenuation at Multidetector CT Is Highly Specific of Ischemia Complicating Small-Bowel Obstruction

PURPOSE To evaluate performance of increased bowel-wall attenuation on unenhanced 64-section multidetector computed tomographic (CT) images for diagnosing bowel-wall ischemia in patients with mechanical small-bowel obstruction (SBO) and to evaluate the diagnostic accuracy of multidetector CT in detecting small-bowel ischemia complicating SBO, with surgical and histopathologic findings as reference standard. MATERIALS AND METHODS The local institutional review board approved this retrospective study; informed consent requirement was waived. In 44 patients (10 men, 34 women; age range, 30-100 years) who were admitted because they were suspected of having SBO and treated surgically within the next 7 days, 45 multidetector CT scans were retrospectively reviewed. Two gastrointestinal radiologists performed independent blinded reviews of images to identify specific signs of ischemia; disagreements were resolved in consensus with a third gastrointestinal radiologist. Results were compared with both findings in prospective radiology reports and surgical and histopathologic findings. Fisher exact and χ(2) tests were used to assess associations between CT signs and ischemia, and the κ statistic was used to assess interobserver agreement. RESULTS In 19 of 45 (42%) multidetector CT scans, ischemia was confirmed at surgery and/or histopathologic examination. Increased bowel-wall attenuation on unenhanced images was significantly associated with ischemia (P < .0001); in this highly selected population, this sign had a 100% (24 of 24) specificity and a 56% (10 of 18) sensitivity. Sensitivity and specificity of multidetector CT for ischemia were 63% (12 of 19) and 92% (24 of 26), respectively, for the prospective reports and 84% (16 of 19) and 96% (25 of 26), respectively, for the consensus review. Decreased segmental bowel-wall enhancement was the most accurate 64-section multidetector CT sign for diagnosing ischemia (sensitivity, 78% [14 of 18]; specificity, 96% [24 of 25]; P < .0001). The small-bowel feces sign was significantly associated with ischemia (P = .0308). CONCLUSION Increased bowel-wall attenuation on unenhanced 64-section multidetector CT images is a specific sign for ischemia complicating SBO. Diagnostic accuracy of 64-section multidetector CT for ischemia associated with SBO was excellent.

Imagerie de l’adénocarcinome du pancréas

Resume Le cancer du pancreas reste la quatrieme cause de mortalite par cancer. La chirurgie reste le seul traitement permettant une guerison. Un diagnostic et un bilan d’extension precis sont imperatifs pour une prise en charge adaptee des patients ayant un cancer du pancreas. Cet article detaille l’apport de chacune des techniques d’imagerie moderne au diagnostic et au bilan d’extension de l’adenocarcinome pancreatique. Le role central de la TDM s’est renforce avec l’apparition des scanners multicoupes.

Imagerie des épaississements de la paroi vésiculaire

Thickening of the gallbladder wall may result from a large spectrum of pathological conditions, intrinsic as well as extrinsic to the biliary tract, and may have different appearances. Accurate diagnosis is usually established after a correlation of imaging findings, laboratory data and clinical history. US remains the initial imaging modality for the evaluation of acute right upper quadrant pain. CT and MRI are complementary to US and have an increasing role in assessing a thickened-wall gallbladder.

Assessment of Bowel Wall Enhancement for the Diagnosis of Intestinal Ischemia in Patients with Small Bowel Obstruction: Value of Adding Unenhanced CT to Contrast-enhanced CT

Purpose To determine whether adding unenhanced computed tomography (CT) to contrast material-enhanced CT improves the diagnostic performance of decreased bowel wall enhancement as a sign of ischemia complicating mechanical small bowel obstruction (SBO). Materials and Methods This retrospective study was approved by the institutional review board, which waived the requirement for informed consent. Two gastrointestinal radiologists independently performed retrospective assessments of 164 unenhanced and contrast-enhanced CT studies from 158 consecutive patients (mean age, 71.2 years) with mechanical SBO. The reference standard was the intraoperative and/or histologic diagnosis (in 80 cases) or results from clinical follow-up in patients who did not undergo surgery (84 cases). Decreased bowel wall enhancement was evaluated with contrast-enhanced images then and both unenhanced and contrast-enhanced images 1 month later. Diagnostic performance of decreased bowel wall enhancement and confidence in the diagnosis were compared between the two readings by using McNemar and Wilcoxon signed rank tests. Interobserver agreement was assessed by using κ statistics and compared with bootstrapping. Results Ischemia was diagnosed in 41 of 164 (25%) episodes of SBO. For both observers, adding unenhanced images improved decreased bowel wall enhancement sensitivity (observer 1: 46.3% [19 of 41] vs 65.8% [27 of 41], P = .02; observer 2: 56.1% [23 of 41] vs 63.4% [26 of 41], P = .45), Youden index (from 0.41 to 0.58 for observer 1 and from 0.42 to 0.61 for observer 2), and confidence score (P < .001 for both). Specificity significantly increased for observer 2 (84.5% [104 of 123] vs 94.3% [116 of 123], P = .002), and interobserver agreement significantly increased, from moderate (κ = 0.48) to excellent (κ = 0.89; P < .0001). Conclusion Adding unenhanced CT to contrast-enhanced CT improved the sensitivity, diagnostic confidence, and interobserver agreement of the diagnosis of ischemia, a complication of mechanical SBO, on the basis of decreased bowel wall enhancement. (©) RSNA, 2016.

CT findings of misleading features of colonic diverticulitis

Colonic diverticulitis (CD) is a common entity whose diagnosis is particularly based on computed tomography (CT) examination, which is the imaging technique of choice. However, unusual CT findings of CD may lead to several difficulties and potential pitfalls: due to technical errors in the management of the CT examination, due to the anatomical situation of the diseased colon, in diagnosing unusual complications that may concern the gastrointestinal tract, intra- and retroperitoneal viscera or the abdominal wall, and in differentiating CD from other abdominal inflammatory and infectious conditions or colonic cancer. The aim of this work is to delineate the pitfalls of CT imaging and illustrate misleading CT features in patients with suspected CD.

Liver T2-weighted MR imaging: assessment of a three-dimensional fast spin-echo with extended echo train acquisition sequence at 1.5 Tesla.

To retrospectively compare image quality and lesion detectability with two T2‐weighted sequences at 1.5 Tesla (T): respiratory‐triggered three‐dimensional fat sat fast‐spin‐echo with extended echo‐train acquisition (3D FSE‐XETA) and respiratory‐triggered two‐dimensional fat‐sat fast recovery fast‐spin‐echo (2D FRFSE).

Torsion d’un appendice épiploïque au sein d’une hernie de Spigel : premier cas rapporté en imagerie

We present the first case illustred in imaging of an epiploic appendage torsion inside a Spigelian hernia.

Central element in liver masses, helpful, or pitfall?

Abstract A central element was first described in focal nodular hyperplasia (FNH) as a so-called “central scar,” and is normally associated with this entity. However, many other liver masses may present with a central element. Depending on its appearance, and the lesion itself, central elements can be essential, helpful, or confusing for diagnosis. Indeed, nodules that develop on liver vascular disorders, fibrolamellar hepatocellular carcinoma, large hemangioma, peripheral cholangiocarcinoma, or epithelioid hemangioenthelioma often present with a central element, thus increasing the level of diagnostic confidence when present. On the other hand, central elements are rare or atypical in liver metastases, hepatocellular adenoma, or hepatocellular carcinoma. In this setting, the presence of a central element can lead to a misdiagnosis. The description and details of the imaging features of these different central elements, especially on MRI, as well as a thorough evaluation of the entire lesion, can improve the diagnostic performance in these cases.

Fat-Fluid Levels in Renal Caliceal Cavities: A CT Sign of Lipolysis Due to Urine Extravasation After Kidney Rupture

WEB This is a Web exclusive article. rine extravasation is a rare complication of urinary tract obstruction. Urine leaks out of tears in the caliceal fornix and, more rarely, the renal pelvis or ureter. In exceptional cases, urine leaks through perforations in the renal wall. Lipolysis of perihilar tissues occurs within a few days of urine extravasation [1]. We describe caliceal fat–fluid levels visualized on CT in a patient who had chronic obstructive pyelonephritis complicated by extensive kidney rupture with extravasation of infected urine. We suggest that urine-induced lysis of perirenal fat may have caused this CT finding. To our knowledge, this is the first report of fat–fluid levels in renal calices.

DIG31 Imagerie des pathologies aigues ischemiques de l’epiploon

Objectifs Demontrer l’interet de l’imagerie dans le diagnostic et la prise en charge des pathologies aigues ischemiques de l’epiploon : torsion d’appendice epiploique et infarctus segmentaire idiopathique du grand epiploon. Materiels et methodes Les dossiers et l’imagerie (echographie et TDM) de 19 patients ayant presente un tableau clinico-radiologique de torsion d’appendice epiploique (n = 14), d’infarctus segmentaire idiopathique du grand epiploon (n = 4) et d’infarctus du ligament hepato-gastrique (petit epiploon) (n = 1) ont ete analyses retrospectivement. Resultats La semiologie radiologique associee a la topographie des anomalies est quasi pathognomonique de torsion de l’epiploon. Dans la quasi-totalite des cas un diagnostic specifique a ete pose permettant une prise en charge medicale du patient avec evolution favorable. Conclusion La bonne connaissance de la semiologie radiologique de la pathologie aigue ischemique de l’epiploon est d’autant plus importante que cette pathologie est non exceptionnelle et qu’elle beneficie alors d’un traitement adapte non chirurgical.