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

PURPOSE: 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). MATERIALS AND METHODS: MR was performed at 1.5T in 53 consecutive patients. Two radiologists blinded to the sequence details reviewed the studies to determine: (i) signal and contrast to noise ratios, (ii) overall image quality, (iii) sensitivity for focal lesion detection. RESULTS: Image assessment scores for the 2D FRFSE sequence were significantly higher than those for the 3D FSE-XETA sequence for overall image quality (P < 0.01) and artifacts (P < 0.001). Sensitivity for liver lesion detection was higher with the 3D FSE-XETA sequence (69.3% versus 57.3%; P < 0.05) compared with the 2D FRFSE sequence. The 3D FSE-XETA sequence improves the reader confidence score (P < 0.01) for liver lesions detection. Inter-observer correlation was higher with the 3D FSE-XETA sequence. CONCLUSION: For T2-weighted liver imaging at 1.5T, the 3D FSE-XETA sequence improves sensitivity, reader confidence score and interobserver correlation for focal liver lesion detection, but it suffers from a lower overall image quality and higher artifacts.

Accuracy of multidetector computed tomography in differentiating primary epiploic appendagitis from left acute colonic diverticulitis associated with secondary epiploic appendagitis.

The objectives of this study are to evaluate the prevalence of left acute colonic diverticulitis (LACD) associated with secondary epiploic appendagitis (SEA) detected by computed tomography (CT); to describe CT features that distinguish LACD associated with SEA from primary epiploic appendagitis (PEA); and to assess the accuracy of CT in diagnosing LACD associated with SEA versus PEA. Institutional review board approval was obtained. We retrospectively identified 46 consecutive patients with LACD between July 2004 and July 2005 and 26 patients with PEA between 2000 and 2005 investigated using multidetector CT. Two radiologists blinded to the final diagnosis reviewed the CT images for findings of LACD-associated SEA or PEA. Each reader classified each CT scan into one of four categories: PEA, LACD-associated SEA, LACD without SEA, and indeterminate. Fisher's exact test and Wilcoxon test were performed to compare the groups. The prevalence of LACD-associated SEA was 71% (33/46) in the LACD group. The accuracy of CT was 100% for diagnosing LACD-associated SEA (33/33), 100% for diagnosing LACD without SEA (13/13), and 96% for diagnosing PEA (25/26). Colon wall thickening, "inflamed diverticulum", extraluminal gas, abscess or phlegmon, multiple paracolic fatty lesions, and a thin hyperattenuated rim were significantly associated with LACD-associated SEA. Neither the dot sign nor parietal peritoneal thickening showed good accuracy for differentiating PEA from LACD-associated SEA. CT is accurate for distinguishing LACD-associated SEA from PEA. The findings that perform best for diagnosing SEA are evidence of diverticulitis, multiple fatty lesions, and a thin hyperattenuated rim.

Location of the transition zone in CT of small-bowel obstruction: added value of multiplanar reformations.

PURPOSE: To assess the additional value of multiplanar reformations (MPR) in comparison with axial images alone for location of the transition zone in CT of mechanical small-bowel obstruction (SBO). MATERIALS AND METHODS: Sixty-nine consecutive patients with mechanical SBO underwent 16-slice multi detector row CT (MDCT). The gold standard for the precise location of the transition zone was established by two experienced abdominal radiologists, unblinded to clinical and surgical reports, reviewing all CT examinations. On a workstation, two blinded readers independently located the transition zone using first axial slices alone and then 1 month later MPR (axial, coronal, sagittal and oblique views) according to a three-point confidence scale. Diagnostic accuracy and mean confidence score were evaluated for both the transverse and multiplanar data sets. RESULTS: Accuracy of transition zone location for reader 1 and reader 2 was 86% and 84% with axial slices alone, and by using MPR 93% (significant: P = 0.03) and 90% (not significant: P = 0.08), respectively. Mean confidence score was significantly increased for both readers using MPR: 0.3 higher (P = 0.0001) and 0.37 higher (P = 0.0001) respectively. CONCLUSION: MPR can increase both accuracy and confidence in the location of the transition zone in CT of SBO.