Étude de corrélation radio-anatomopathologique sur pièces de prostatectomie radicale des facteurs d agressivité du cancer de la prostate (score de Gleason et volume tumoral) en IRM 1.5 Tesla avec antenne de surface : quel est l apport de la séquence de diffusion ?

Cette étude a pour but de corréler le score de Gleason et le coefficient de diffusion apparent (ADC) dans les foyers de cancer prouvés sur pièce de prostatectomie, et d établir laquelle des 3 séquences de routine permet la mesure du volume la mieux corrélée au volume anatomo-pathologique. 45 patients (78 foyers tumoraux) ont bénéficié d une IRM, incluant les séquences T2, T1 de contraste dynamique et diffusion. La mesure du volume et de l ADC des foyers en IRM a été effectuée après repérage et comparaison sur les coupes histologiques. L ADC est négativement corrélé au score de Gleason (p<0.001), pour les 3 grades de cancer : bas, intermédiaire et haut grade. La séquence de contraste dynamique est la mieux corrélée au volume tumoral mesuré en pathologie comparativement aux séquences T2 et diffusion. L ADC est négativement corrélé au score de Gleason. Nous préconisons de mesurer le foyer tumoral sur la séquence T1 de contraste dynamique.To access the relationship between apparent diffusion coefficient (ADC) value on 1.5 Tesla magnetic resonance imaging (MRI) and Gleason 's score in prostate cancer, obtained from whole mount specimens after radical prostatectomy (RP), and to determine which MRI sequence used for prostate cancer evaluation allows a better estimation of tumor's volume. 45 men with 78 foci of prostate cancer who underwent MR imaging, including a single-shot EPI diffusion weighted MRI (b=0 & b=600 mm /sec), T2 weighted MRI and dynamic contrast enhanced T1-weighted MRI, with a 12-channel pelvic phased-array body coil, within 2 months before RP, were included. After the RP, the prostate was whole-mounted and cancer foci were drawn on whole mounts pathologic slides. Two radiologists in consensus estimated the cancer volume in each of the 3 sequences, and measured the ADC value in the cancer zone. Comparison of mean ROI ADC value and tumor's Gleason grade was performed with a Scheffe's test and correlation between tumor's volumes was calculated for each sequence by using concordance correlation coefficients (CCCs). ADC value was found to be related to the Gleason grade (p<0.001); for low, intermediate and high grade tumor (p<0.005). Dynamic contrast enhanced T1-weighted imaging was statistically better to estimate the tumor volume than the two others (p<0.005). Mean ADC value was found to be negatively correlated to Gleason grade in prostate cancer proved on whole mount prostatectomy specimens. Dynamic contrast enhanced T1-weighted imaging was the most accurate sequence to measure tumor volume in prostate cancer at 1.5 Tesla using a phased-array coil.ST QUENTIN EN YVELINES-BU (782972101) / SudocSudocFranceF

Increased unenhanced bowel-wall attenuation: a specific sign of bowel necrosis in closed-loop small-bowel obstruction

International audienceOBJECTIVES: To identify computed tomography (CT) findings associated with bowel necrosis in patients with surgically confirmed strangulating closed-loop small-bowel obstruction (CL-SBO) due to adhesions or internal hernia. METHODS: This retrospective study was approved by our institutional review board, and informed consent was waived. To identify CT signs of bowel necrosis, two gastrointestinal radiologists performed blinded, independent, retrospective reviews of 41 CT studies from consecutive patients who had CL-SBO due to adhesions or internal hernias and who underwent surgery within 48 h. On the basis of surgical and pathological findings, patients were classified as having reversible ischemia or histologically documented necrosis. Univariate statistical analyses were performed to assess associations between CT signs and bowel necrosis. Kappa statistics were computed to assess interobserver agreement. RESULTS: We included 25 (61%) women and 16 (39%) men with a median age of 79 years. Bowel necrosis was found in 25/41 (61%) patients and ischemic but viable bowel in 16/41 (39%) patients. Increased unenhanced bowel-wall attenuation was the only CT finding significantly associated with bowel necrosis (p = 0.0002). This sign had 58% (95% CI, 37-78) sensitivity and 100% (95% CI, 79-100) specificity for necrosis. Interobserver agreement was fair (0.59; 95% CI, 0.37-0.82). CONCLUSION: Increased unenhanced bowel-wall attenuation is specific for bowel necrosis and should lead to prompt surgery for bowel resection. KEY POINTS: \textbullet Increased unenhanced bowel-wall attenuation is the only sign specific for necrosis \textbullet Decreased bowel-wall enhancement is not relevant for differentiating reversible ischemia from necrosis \textbullet Preoperative knowledge of bowel necrosis is helpful to plan adequate surgery

Acute Jejunoileal Diverticulitis: Multicenter Descriptive Study of 33 Patients

International audienceOBJECTIVE: Acute jejunoileal diverticulitis is a very rare and potentially serious disease affecting mostly elderly patients. The diagnosis is based on imaging but remains underrecognized. The purpose of this study is to describe the clinical and CT features and the outcomes of patients with acute jejunoileal diverticulitis. MATERIALS AND METHODS: Cases of acute jejunoileal diverticulitis managed at three French hospitals November 2005 through January 2015 were identified retrospectively. The final diagnosis relied either on a clinical and radiologic data review by a panel of experts or on surgical findings. Demographic, clinical, laboratory, and 18-month outcome data were collected. CT scans were reviewed by two radiologists who reached a consensus about the presence of an inflammatory diverticulum, evidence of complications, and presence of other bowel diverticula. RESULTS: We identified 33 cases of acute jejunoileal diverticulitis in 33 patients with a median age of 78 years, including 30 (91%) patients in whom an inflammatory diverticulum was identified at the jejunum (n = 26, 87%) or ileum (n = 4, 13%). Extraintestinal gas was seen in 10 (30%) patients and extraintestinal fluid in 11 (33%) patients. Other small-bowel diverticula were visible in all 33 patients. The diverticulitis was mild and resolved with nonoperative treatment in 22 (67%) patients and was severe in the remaining 11 (33%) patients, eight of whom required emergent surgery. CONCLUSION: Acute jejunoileal diverticulitis is a rare and usually nonserious condition that chiefly involves the jejunum. A detailed CT assessment may allow nonoperative treatment

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

International audiencePurpose 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