Living donor candidates for right hepatic lobe transplantation: evaluation at CT cholangiography--initial experience

PURPOSE: To retrospectively evaluate computed tomographic (CT) cholangiography in the depiction of second-order biliary tract anatomy in living donor candidates for right hepatic lobe transplantation. MATERIALS AND METHODS: Human research committee approval was obtained, informed consent was not required, and the study was compliant with the Health Insurance Portability and Accountability Act. The authors identified all living right-lobe liver donor candidates who underwent CT cholangiography at their institution between October 2001 (when CT cholangiography was introduced at the institution) and March 2003 (n = 62). There were 41 men (mean age, 36 years; range, 18-55 years) and 21 women (mean age, 40 years; range, 22-55 years). Two readers in consensus rated quality of second-order bile duct visualization at CT cholangiography on a four-point scale (0, not seen; 3, excellent visualization) and noted the presence of variant second-order biliary tract branching anatomy. CT cholangiography findings were compared with those at surgery in subjects who underwent right hepatic lobe retrieval (n = 24). In addition, adult donors who underwent right hepatic lobe retrieval between January 2000 and March 2003 (29 men, mean age, 35 years [range, 20-52 years]; 18 women, mean age, 38 years [range, 23-54 years]) were identified. Numbers of donors who underwent intraoperative cholangiography before and after the introduction of CT cholangiography were compared by using the Fisher exact test. RESULTS: The mean second-order bile duct score at CT cholangiography was 2.9 (range, 2-3). Of 24 subjects who underwent right lobe retrieval, biliary tract anatomy determined at CT cholangiography was concordant with findings at surgery in 23 (96%). Variant second-order branching anatomy was seen in 13 subjects (54%) at surgery; one variant branch was missed at CT cholangiography. Of 47 subjects who underwent right hepatic lobe retrieval, significantly fewer subjects required conventional intraoperative cholangiography after the introduction of CT cholangiography (three of 24 subjects [12%]) than before (23 of 23 subjects; P < .0001). CONCLUSION: CT cholangiography accurately depicts biliary tract anatomy in living donor candidates for right hepatic lobe transplantation, and donors who undergo preoperative CT cholangiography are unlikely to need conventional intraoperative cholangiography.     

Accuracy of liver fat quantification at MR imaging: comparison of out-of-phase gradient-echo and fat-saturated fast spin-echo techniques--initial experience

PURPOSE: To retrospectively determine the relative accuracy of liver fat quantification with out-of-phase gradient-echo magnetic resonance (MR) imaging and fat-saturated fast spin-echo MR imaging in patients with and without cirrhosis, with histologic analysis as the reference standard. MATERIALS AND METHODS: Committee on Human Research approval was obtained. Patient consent was not required. Data collection ended before HIPAA regulations were implemented, but patient anonymity was maintained. Twenty-seven patients, 16 with cirrhosis, were retrospectively identified who underwent MR imaging before histopathologic evaluation of liver fat at biopsy or surgery. The patient population consisted of 15 male and 12 female patients (mean age, 55 years; range, 16-75 years). One radiologist blinded to the histopathologic results recorded mean signal intensity derived from three regions of interest placed in the right and left lobes of the liver on three sections and signal intensity of the spleen from one region of interest within the same section. Liver fat was quantified with the relative loss of signal intensity on out-of-phase images compared with that on in-phase T1-weighted gradient-echo images and with relative loss of signal intensity on T2-weighted fast spin-echo MR images obtained with fat saturation compared with those obtained without fat saturation. Hotelling t test was used to compare correlation coefficients between relative signal intensity differences and histopathologically determined percentage of fat. RESULTS: In patients without cirrhosis, liver fat quantification with fat-saturated fast spin-echo MR imaging was significantly better than it was with out-of-phase gradient-echo MR imaging (r = 0.92 vs 0.69, P < .01). In patients with cirrhosis, liver fat quantification was correlated only with fat-saturated fast spin-echo MR imaging (r = 0.76, P < .01); the relative signal intensity loss on out-of-phase gradient-echo MR images was not correlated with histopathologically determined percentage of fat (r = 0.25, P = .36). CONCLUSION: Preliminary results suggest liver fat may be more accurately quantified with fat-saturated fast spin-echo MR imaging than with out-of-phase gradient-echo MR imaging, especially in patients with cirrhosis.     

Large variations occur in bone density measurements of children when using different software

BACKGROUND: Paediatric dual X-ray absorptiometry (DXA) studies present a number of technical problems. One of these is that the edge detection algorithms designed for the adult skeleton may fail for paediatric studies. Hologic provide alternative algorithms for low bone density studies. AIM: To assess low-density software for the analysis of paediatric DXA studies and to compare with the adult protocol. METHODS: Our centre has scanned 450 normal children as part of a normal range study. A subgroup of 103 children was selected using a random number generator. The group was distributed evenly between males and females and across the age range 5-17 years. Each individual underwent both a lumbar spine and a whole-body scan on a Hologic QDR-4500W DXA scanner. Both scans were analysed using the standard adult protocol and then re-analysed using the Hologic experimental paediatric protocol for whole body and the Hologic low-density protocol for lumbar spine. RESULTS: Both lumbar spine protocols showed an increase in bone mineral density with age; however, the low-density protocol always produced a lower bone mineral density result than the adult protocol. Bland-Altman analysis showed limits of agreement of 0.031-0.093 g x cm(-2) (male, 0.032-0.089 g x cm(-2); female, 0.031-0.096 g x cm(-2)). This represents a mean difference of 9%. Five results showed differences greater than the upper limit of agreement. All these cases were children under 11 years of age who had large areas of spine not identified as bone by the adult protocol. These children were all below the 30th percentile for the body mass index. The whole-body protocols showed similar increases in bone mineral density with age; however, the experimental paediatric protocol always produced a lower bone mineral density result than the adult protocol. Paired results showed limits of agreement of 0.0668-0.130 g x cm(-2) (male, 0.063-0.124 g x cm(-2); female, 0.073-0.134 g x cm(-2)). This represents a mean difference of 11%. Five results showed differences greater than the upper limit of agreement. CONCLUSIONS: For anteroposterior (AP) lumbar spine scans, the use of the paediatric algorithm in children under 11 years of age would prevent the largest failures in analysis. For whole-body scanning, the adult algorithm showed no major failures in children of 11 years or older. It is hoped that forthcoming improvements in whole-body density analysis will improve the results for those under 11 years of age. Normal range data should be generated for any new algorithm to allow proper interpretation of clinical studies.     

Peritoneal calcification: causes and distinguishing features on CT

OBJECTIVE: We undertook this study to determine the causes of peritoneal calcification seen on CT and to investigate which CT features distinguish benign from malignant peritoneal calcification. MATERIALS AND METHODS: Seventeen patients with peritoneal calcification were identified through retrospective review of reports from 74765 abdominopelvic CT examinations performed during a 7-year period. We determined the cause of peritoneal calcification by examining medical and histopathologic records. Calcification morphology was classified as nodular or sheetlike on the basis of the consensus interpretation by two independent radiologists. The radiologists also recorded the presence or absence of associated soft-tissue components or lymph node calcification. The association between the CT findings and the cause of calcification was assessed using chi-square analysis. RESULTS: Peritoneal calcification was due to peritoneal dialysis (n = 4), prior peritonitis (n = 3), cryptogenic origin (n = 1), or peritoneal spread of ovarian carcinoma (n = 9). Sheet-like calcification was more common in patients with benign calcification (seven of eight patients) than in those with malignant calcification (two of nine patients, p < 0.05). Nodal calcification was seen only in patients with malignant calcification (five of nine patients vs none of eight, p < 0.05). CONCLUSION: Common causes of peritoneal calcification are dialysis, prior peritonitis, or ovarian cancer; sheetlike calcification indicates a benign cause, whereas associated lymph node calcification strongly suggests malignancy.