Colon cancer: comprehensive evaluation with 64-section CT colonography using water enema as intraluminal contrast agent-a pictorial review.

Sixty-four-section CT colonography with water enema combines intracolonic neutral contrast agent with high-resolution CT images of the abdomen. Owing to submillimeter isotropic voxels, high-quality reformatted images are obtained. High-resolution images offer added value for the detection and localization of colonic lesions, evaluation of the local extent of the disease, and depiction, if any, of synchronous colorectal lesions and distant metastases. Sixty-four-section CT colonography with water enema has a major role in the evaluation of patients with colon cancer before planning therapy. It can be used to complement failed or incomplete colonoscopy and investigate the colon in elderly patients.

Impact of 64-slice coronary CT on the management of patients presenting with acute chest pain: results of a prospective two-centre study.

OBJECTIVE: Our two-centre prospective study evaluates the usefulness of 64-slice coronary computed tomography (CCT) to rule out significant coronary artery stenosis in patients admitted in emergency departments (ED) for acute coronary syndromes (ACS) with low-to-intermediate risk score. METHODS: Patients (175) admitted for acute chest pain (ACP), unmodified electrocardiogram and first troponin measurement within normal ranges were included. A second troponin measurement and a 64-slice CCT within 24 h were performed. Major adverse cardiac events (MACE) were recorded during follow-up (6 months ± 2). RESULTS: 64-slice CCT was either normal or showed non-significant coronary stenosis in the majority of patients (78%). 64-slice CCT depicted significant stenosis (>50% diameter) in 22% of patient whereas initial clinical and biological evaluation was reassuring. For negative CCTs, elevated troponin at second measurement did not modify the strategy or treatment of patients. No MACEs were noted during follow up. In 12% of patients CCT identified unsuspected non-coronary abnormalities. CONCLUSION: Our study confirms 64-slice CCT utility to rule out significant coronary artery stenosis in 8/10 patients admitted in ED with ACP or ACS with low-to-intermediate risk score. Early discharge with a negative 64-slice CCT is associated with very low risk of cardiac events at 6 months. KEY POINTS: • 64-slice coronary computed tomography (CCT) offers a critical role in acute chest pain. • 64-slice CCT allows differentiation between significant and non-significant coronary artery stenosis. • Normal 64-slice CCT allows rapid discharge of patients with ACP. • 64-slice CCT helps make appropriate therapeutic decision in patients with ACP.

Differentiation between cavernous hemangiomas and untreated malignant neoplasms of the liver with free-breathing diffusion-weighted MR imaging: comparison with T2-weighted fast spin-echo MR imaging.

OBJECTIVE: To test interobserver variability of ADC measurements and compare the diagnostic performances of free-breathing diffusion-weighted (FBDW) with that of T2-weighted FSE (T2WFSE) MR imaging for differentiating between cavernous hemangiomas and untreated malignant hepatic neoplasms. MATERIALS AND METHODS: Thirty-five patients with cavernous hemangiomas and 35 with untreated hepatic malignant neoplasms had FBDW and T2WFSE MR imaging. Hepatic lesions were characterized with ADC measurement and visual evaluation. Interobserver agreement for ADC measurement was calculated. Association between ADC value and lesion type was assessed using univariate analysis. Sensitivity, specificity and accuracy of ADC values and visual evaluation of MR images for the diagnosis of untreated malignant hepatic neoplasm were compared. RESULTS: ADC measurements showed excellent interobserver correlation (intraclass correlation coefficient=0.980). Malignant neoplasms had lower ADC values than hemangiomas for the two observers (1.11×10(-3) mm2/s±.21×10(-3) vs. 1.77×10(-3) mm2/s±.29×10(-3) for observer 1 and 1.11×10(-3) mm2/s±.19×10(-3) vs. 1.79×10(-3) mm2/s±.32×10(-3) for observer 2) and univariate analysis found significant correlations between lesion type and ADC values. Depending on ADC threshold value, accuracy for the diagnosis of malignant neoplasm varied from 82.9% to 94.3%. Using visual evaluation, FBDW showed better specificity and accuracy than T2WFSE MR images for the diagnosis of malignant neoplasm (97.1% vs. 77.1% and 94.3% vs. 62.9%, respectively). CONCLUSION: FBDW imaging provides reproducible quantitative information and surpasses the value of T2WFSE MR imaging for differentiating between cavernous hemangiomas and untreated malignant hepatic neoplasms.

Preoperative detection of hepatic metastases: comparison of diffusion-weighted, T2-weighted fast spin echo and gadolinium-enhanced MR imaging using surgical and histopathologic findings as standard of reference.

PURPOSE: The purpose of this study was to retrospectively compare the respective sensitivities of diffusion-weighted (DW), T2-weighted fast spin-echo (T2WFSE) and gadolinium chelate-enhanced MR imaging in the preoperative detection of hepatic metastases using intraoperative ultrasonographic and histopathologic findings as the standard of reference. MATERIALS AND METHODS: Twenty-seven patients with 64 surgically and histopathologically proven hepatic metastases had MR imaging of the liver, including DW, T2WFSE and dynamic gadolinium chelate-enhanced MR imaging. Images from each MR sequence were separately analyzed by two readers with disagreements resolved by consensus readings. The findings on MR images were compared with intraoperative ultrasonographic and histopathologic findings on a lesion-by-lesion basis to determine the sensitivity of each MR sequence. Statistical review of the lesion-by-lesion analysis was performed with the McNemar test. RESULTS: DW, T2WFSE and gadolinium chelate-enhanced MR imaging allowed the depiction of 54/64 (84.4%; 95% CI: 73.1-92.2%), 44/64 (68.8%; 95% CI: 55.9-79.8%), and 51/64 (79.7%; 95% CI: 67.8-88.7%) hepatic metastases respectively. DW MR images allowed depiction of significantly more hepatic metastases than did T2WFSE and was equivalent to gadolinium chelate-enhanced MR imaging (P=.002 and P=.375, respectively). CONCLUSION: DW MR imaging is superior to T2WFSE imaging and equivalent to gadolinium chelate-enhanced MR imaging for the preoperative detection of hepatic metastases. Further studies however are needed to determine at what extent DW MR imaging can be used as an alternative to gadolinium chelate-enhanced MR imaging for the preoperative depiction of hepatic metastases.

Suspected anastomotic recurrence of Crohn disease after ileocolic resection: evaluation with CT enteroclysis.

PURPOSE: To determine the utility of computed tomographic (CT) enteroclysis for characterization of the status of the anastomotic site in patients with Crohn disease who had previously undergone ileocolic resection. MATERIALS AND METHODS: Written informed consent was prospectively obtained from all patients, and the institutional review board approved the study protocol. CT enteroclysis findings in 40 patients with Crohn disease who had previously undergone ileocolic resection were evaluated independently by two readers. Endoscopic findings, histopathologic findings, and/or the Crohn disease activity index was the reference standard. Interobserver agreement between the two readers was calculated with kappa statistics. Associations between CT enteroclysis findings and anastomotic site status were assessed at univariate analysis. The sensitivity, specificity, and accuracy of CT enteroclysis, with corresponding 95% confidence intervals (CIs), for the diagnosis of normal versus abnormal anastomosis and the diagnosis of anastomotic recurrence versus fibrostenosis were estimated. RESULTS: Interobserver agreement regarding CT enteroclysis criteria was good to perfect (kappa = 0.72-1.00). At univariate analysis, stratification and anastomotic wall thickening were the two most discriminating variables in the differentiation between normal and abnormal anastomoses (P < .001). Stratification (P < .001) and the comb sign (P = .026) were the two most discriminating variables in the differentiation between anastomotic recurrence and fibrostenosis. In the diagnosis of anastomotic recurrence, severe anastomotic stenosis was the most sensitive finding (95% [20 of 21 patients]; 95% CI: 76.18%, 99.88%), both comb sign and stratification had 95% specificity (18 of 19 patients; 95% CI: 73.97%, 99.87%), and stratification was the most accurate finding (92% [37 of 40 patients]; 95% CI: 79.61%, 98.43%). In the diagnosis of fibrostenosis, both severe anastomotic stenosis and anastomotic wall thickening were 100% sensitive (eight of eight patients; 95% CI: 63.06%, 100.00%), and using an association among five categorical variables, including severe anastomotic stenosis, anastomotic wall thickening with normal or mild mucosal enhancement, absence of comb sign, and absence of fistula, yielded 88% sensitivity (seven of eight patients; 95% CI: 47.35%, 99.68%), 97% specificity (31 of 32 patients; 95% CI: 83.78%, 99.92%), and 95% accuracy (38 of 40 patients; 95% CI: 83.08%, 99.39%). CONCLUSION: CT enteroclysis yields objective and relatively specific morphologic criteria that help differentiate between recurrent disease and fibrostenosis at the anastomotic site after ileocolic resection for Crohn disease. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.09091165/-/DC1.

Free-breathing diffusion-weighted single-shot echo-planar MR imaging using parallel imaging (GRAPPA 2) and high b value for the detection of primary rectal adenocarcinoma.

Our objective was to determine the diagnostic accuracy of a free-breathing diffusion-weighted single-shot echo-planar magnetic resonance imaging (FBDW-SSEPI) technique with parallel imaging and high diffusion factor value (b = 1000 s/mm2) in the detection of primary rectal adenocarcinomas. Thirty-one patients (14M and 17F; mean age 67 years) with histopathologically proven primary rectal adenocarcinomas and 31 patients without rectal malignancies (14M and 17F; mean age 63.6 years) were examined with FBDW-SSEPI (repetition time (TR/echo time (TE) 3900/91 ms, gradient strength 45 mT/m, acquisition time 2 min) at 1.5 T using generalized autocalibrating partially parallel acquisitions (GRAPPA, acceleration factor 2) and a b value of 1000 s/mm2. Apparent diffusion coefficients (ADCs) of rectal adenocarcinomas and normal rectal wall were measured. FBDW-SSEPI images were evaluated for tumour detection by 2 readers. Sensitivity, specificity, accuracy and Youden score for rectal adenocarcinoma detection were calculated with their 95% confidence intervals (CI) for ADC value measurement and visual image analysis. Rectal adenocarcinomas had significantly lower ADCs (mean 1.036 x 10(-3)+/- 0.107 x 10(-3) mm2/s; median 1.015 x 10(-3) mm2/s; range (0.827-1.239) x 10(-3) mm2/s) compared with the rectal wall of control subjects (mean 1.387 x 10(-3)+/- 0.106 x 10(-3) mm2/s; median 1.385 x 10(-3) mm2/s; range (1.176-1.612) x 10(-3) mm2/s) (p < 0.0001). Using a threshold value < or = 1.240 x 10(-3) mm2/s, all rectal adenocarcinomas were correctly categorized and 100% sensitivity (31/31; 95% CI 95-100%), 94% specificity (31/33; 95% CI 88-100%), 97% accuracy (60/62; 95% CI 92-100%) and Youden index 0.94 were obtained for the diagnosis of rectal adenocarcinoma. FBDW-SSEPI image analysis allowed depiction of all rectal adenocarcinomas but resulted in 2 false-positive findings, yielding 100% sensitivity (31/31; 95% CI 95-100%), 94% specificity (31/33; 95% CI 88-100%), 97% accuracy (60/62; 95% CI 92-100%) and Youden index 0.94 for the diagnosis of primary rectal adenocarcinoma. We can conclude that FBDW-SSEPI using parallel imaging and high b value may be helpful in the detection of primary rectal adenocarcinomas.

Differentiation between true focal liver lesions and pseudolesions in patients with fatty liver: evaluation of helical CT criteria.

OBJECTIVE: To determine the potential of helical CT for differentiating true lesions from pseudolesions in patients with fatty liver. METHODS: Helical CT of 44 patients with diffuse fatty liver (22 with true lesions; 22 with pseudolesions) were reviewed by two observers with regard to morphological features of visible lesions. Univariate analysis was used to detect discriminating criteria for the diagnosis of true lesions. RESULTS: Interobserver agreement was excellent for 9/10 morphological criteria (kappa = 0.831-1). True lesions were more frequently distant from the liver capsule (50.00% vs. 4.55%), located in the right lobe (72.73% vs. 31.82%), round (86.36% vs. 54.55%), heterogeneous (27.27% vs. 0.00%) and had ill-defined margins (40.91% vs. 13.64%) compared with pseudolesions (P < 0.05). Using univariate analysis, a location distant from the liver capsule was the most discriminating variable to differentiate between true and pseudolesions (P = 0.0060). Hyperattenuating content and round shape were the most sensitive criteria (sensitivity = 90.91% and 86.36%, respectively) for the diagnosis of true lesions, and heterogeneity, vascular displacement and encapsulation were the three most specific ones (specificity = 100.00%). Best accuracy was obtained with an association of the three variables (accuracy = 86.36%). CONCLUSION: Helical CT provides objective and discriminating morphological criteria to differentiate between true lesions and pseudolesions in patients with fatty liver.

Crohn's disease: multi-detector row CT-enteroclysis appearance of the appendix.

The objective of our retrospective study was to determine the MDCT-enteroclysis appearance of the appendix in patients with Crohn's disease and to correlate this appearance with the status of the disease. We reviewed the MDCT-enteroclysis examinations of 76 patients with Crohn's disease. Images were analyzed for visualization of the appendix, largest axial diameter of the appendix and degrees of enhancement. Findings were correlated with the status of the disease (active vs. nonactive) and compared with those observed in a control group. Among the various variables, hyperenhancement of the appendiceal wall was found in 18.9% of patients with active disease and in no patients with inactive disease nor in the control group (P = 0.0023). This sign had a specificity of 100% for differentiating between active and inactive Crohn's disease. We conclude that increased appendiceal wall enhancement is, at a statistically significant level, more frequently observed in patients with active Crohn's disease by comparison with patients with inactive disease and control subjects. This result suggests that this finding may be used as an additional MDCT-enteroclysis finding to determine the activity of the disease.

Multi-detector row CT of patients with acute intestinal bleeding: a new perspective using multiplanar and MIP reformations from submillimeter isotropic voxels.

Acute intestinal bleeding is a severe condition, with a mortality rate of up to 40% in case of associated hemodynamic instability. The diagnosis of acute intestinal bleeding is often challenging and to date, there is no definite consensus upon the most appropriate technique for this specific diagnosis. This pictorial essay illustrates our preliminary use of multiplanar (MPR) and maximum intensity projection (MIP) reformations using MDCT scanner with submillimeter and isotropic voxels as an adjunct to axial images in patients with acute intestinal bleeding. MDCT examinations were routinely performed with 64-slice helical CT scanner and images were reconstructed 0.6-mm thickness at 0.5-mm intervals. Multiplanar reconstructions and MIP views were created with a commercially available workstation. Reformatted images from submillimeter isotropic voxels enhanced the depiction of subtle vascular abnormalities and served as a useful adjunct to the axial plane images to improve diagnostic capabilities. Although we are aware that reformatted images should not replace careful analysis of the axial images in patients with acute gastrointestinal bleeding, reformatted images from submillimeter isotropic voxels may clarify the cause of the bleeding, add confidence to image analysis and help interventional radiologists or surgeons improving planning approach.

Abdominopelvic extra-enteric findings at computed tomography enteroclysis: a retrospective evaluation of 430 consecutive patients.

BACKGROUND: Our objective was to retrospectively determine the frequency with which CT enteroclysis (CTE) shows abdominopelvic extra-enteric abnormalities and to analyze how such findings had actually and prospectively affected patient's care. METHODS: The CTE examinations of 430 consecutive patients were retrospectively and blindly reviewed for the presence of possible pathologic conditions that might have affected abdominopelvic organs other than the small bowel. Extra-enteric abnormalities were categorized as negligible or important and correlated with patient's outcome and thus classified as having or not influenced patient's care. RESULTS: Abdominopelvic extra-enteric abnormalities were present on CTE in 258 (60%) of 430 patients. Retrospective analysis of CTE images revealed negligible abnormalities in 217 patients (217/430, 50.5%) and important ones in 41 patients (41/430, 9.5%). Among the 41 patients with important abnormalities, CTE demonstrated already documented abnormalities in 22 patients (22/41, 53.7%) and unknown abnormalities in 19 patients (19/41, 46.3%). In the latter 19 patients, the detection of unknown abnormalities altered patient's care in 18 (94.7%) of them. In one patient (1/19, 5.3%), important abnormality was detected during retrospective evaluation but not prospectively, resulting in a delayed treatment, yielding missed important abnormality rate of 2.4% (1/41). CONCLUSIONS: Abdominopelvic extra-enteric abnormalities are frequent on CTE, but their depictions rarely alter patient's care. However, in a few patients (19/430; 4.4%), CTE may reveal unknown extra-enteric abnormalities that require further evaluation and have substantial impact on patient's management.

Replaced right hepatic artery coursing ventral to the portal vein: demonstration with 64-row CT and 3D reformatted images.

We report one case of replaced right hepatic artery coursing ventral to the portal vein. This variation, which was demonstrated by 64-row CT angiography and three-dimensional reformatted images, has never been reported. Surgeons involved in hepatic and biliopancreatic procedures should be aware of this possible variation, which has important surgical implications.

Small bowel involvement in blue rubber bleb nevus syndrome: MR imaging features.

Blue rubber bleb nevus syndrome (BRBNS) is a rare condition which is characterized by multiple venous malformations that may affect several organs. Gastrointestinal lesions, which mostly involve the small bowel and distal colon, may be responsible for gastrointestinal bleeding, causing more frequently chronic anemia. We report herein two cases of BRBNS causing gastrointestinal bleeding which were investigated by means of MR imaging. All venous malformations showed markedly high signal intensity on fat-suppressed T2-weighted MR images. In addition, extraintestinal venous malformations displayed high signal intensity similar to that of small bowel venous malformations. Fat-suppressed T2-weighted TSE images show both small bowel and colonic involvement, thus providing useful information relative to the most appropriate therapeutic approach to be used. MR imaging is especially helpful when capsule endoscopy or enteroscopy are contraindicated or not feasible. In addition, because of lack of radiation, MR imaging can be performed repeatedly to assess the evolution of the disease before a planned surgery or endoscopic resection. Also, because BRBNS is by essence a multifocal condition with extraintestinal involvement, MR imaging appears as an appropriate imaging technique to investigate the multiple locations of the disease in one session, thus replacing multiple examinations.