Materials and Methods: Institutional review board approval was obtained, with waiver of informed consent. A total of 245 consecutive patients (133 men, 112 women), including 48 patients who subsequently underwent cholecystectomy, were examined. Two independent observers evaluated the CT data set on the basis of axial sections, coronal and sagittal multiplanar reformations, and three-dimensional volume rendering. The relationship between the cystic arteries and the Calot triangle—which is bordered by the undersurface of the liver, common hepatic duct, and cystic duct—was also evaluated, and each patient was classified on the basis of the origin of the cystic arteries and the course to the Calot triangle. Statistical analysis was performed, and percentages and confidence intervals were calculated.

Results: The cystic arteries were delineated in 234 of the 245 patients. Both the Calot triangle and the cystic arteries were delineated in 223 patients. One cystic artery was seen in the Calot triangle in 173 patients, and two cystic arteries were seen in the Calot triangle in 12. One artery in the Calot triangle with accessory arteries from different origins outside the Calot triangle was seen in 18 patients, and no cystic artery was identified in 20. Cystic arteries were seen in 42 (92%; 95% confidence interval: 87%, 98%) of the 48 patients who subsequently underwent cholecystectomy. The relationship between the cystic arteries and the Calot triangle was in agreement with the surgical records for all patients.

Conclusion: The configuration of the cystic duct and cystic arteries can be depicted preoperatively with 64–detector row CT in patients scheduled to undergo cholecystectomy.

© RSNA, 2008

Materials and Methods: The study had institutional review board approval; all participants gave informed consent. Data in a total of 383 prospectively enrolled patients who underwent duplex Doppler US and screening endoscopy were divided into training (n = 240) and validation (n = 143) sets. Duplex Doppler US indexes, including mean portal vein velocity (PVV), hepatic impedance indexes, splenic impedance indexes, and the splenic index were evaluated with univariate and multivariate logistic regression analyses to find the independent factors predictive of the presence of esophageal varices. Receiver operating characteristic (ROC) curves were constructed for these factors to evaluate diagnostic accuracy in the training set and reproducibility in the validation set.

Results: Multivariate logistic regression analysis showed that splenic index and mean PVV were predictive of the presence of esophageal varices in the training set. A splenoportal index (SPI) was calculated as the splenic index divided by mean PVV to amplify the opposite effects on esophageal varices. Areas under ROC curves for SPI were significantly higher than those for the splenic index (0.93 vs 0.90, P = .02) and mean PVV (0.93 vs 0.67, P < .001) in the training set and in the validation set (0.96 vs 0.91 for splenic index, P = .01; 0.93 vs 0.80 for mean PVV, P < .001). An SPI threshold of 3.0 had 92% sensitivity, 93% specificity, 91% positive predictive value, and 94% negative predictive value for esophageal varices. Applying this cutoff value correctly predicted the presence or absence of esophageal varices in 92% of the patients without screening endoscopy.

Conclusion: SPI can serve as a useful noninvasive index to predict the presence or absence of esophageal varices.

© RSNA, 2008

Materials and Methods: After institutional review board approval and informed consent, 25 men and 22 women (mean age, 65.8 years) with colorectal adenocarcinoma underwent 65-second CT perfusion study. Blood volume, blood flow, and permeability–surface area product were determined for 40- or 120-mm² circular ROIs placed at the tumor edge and center and around (outlining) visible tumor. ROI analysis was repeated by two observers in different subsets of patients to assess intra- and interobserver variation. Measurements were compared by using analysis of variance; a difference with P = .002 was significant.

Results: Blood volume, blood flow, and permeability–surface area product measurements were substantially higher at the edge than at the center for both 40- and 120-mm² ROIs. For 40-mm² ROI, means of the three measurements were 6.9 mL/100 g (standard deviation [SD], 1.4), 108.7 mL/100 g per minute (SD, 39.2), and 16.9 mL/100 g per minute (SD, 4.2), respectively, at the edge versus 5.1 mL/100 g (SD, 1.5), 56.3 mL/100 g per minute (SD, 33.1), and 13.9 mL/100 g per minute (SD, 4.6), respectively, at the center. For 120-mm² ROI, means of the three measurements were 6.6 mL/100 g (SD, 1.3), 96.7 mL/100 g per minute (SD, 42.5), and 16.3 mL/100 g per minute (SD, 5.6), respectively, at the edge versus 5.1 mL/100 g (SD, 1.4), 58.3 mL/100 g per minute (SD, 32.5), and 13.4 mL/100 g per minute (SD, 4.3) at the center (P < .0001). Measurements varied substantially depending on the ROI size; values for the ROI for outlined tumor were intermediate between those at the tumor edge and center. Inter- and intraobserver agreement was poor for both 40- and 120-mm² ROIs.

Conclusion: Position and size of tumor ROI and observer variation substantially influence ultimate perfusion values. ROI for outlined entire tumor is more reliable for perfusion measurements and more appropriate clinically than use of arbitrarily determined smaller ROIs.

© RSNA, 2008

Materials and Methods: This was a retrospective single institution study approved by the institutional review board and compliant with requirements of the HIPAA. Multidetector CT cholangiography was performed after slow infusion of 20 mL of iodipamide meglumine 52% diluted in 80 mL of normal saline in 143 consecutive potential liver donors (81 men and 62 women; mean age, 37 years); 43 received premedication with intravenous morphine sulfate (0.04 mg per kilogram of body weight) and 100 did not. Two independent readers recorded common bile duct diameter and area on axial CT images. Readers also scored bile duct visualization, including all second-order biliary branches, on a four-point scale (0, not seen; 3, excellent visualization).

Results: For scans obtained without and those obtained with morphine, there was no significant difference in the mean common bile duct diameter (4.1 vs 4.3 mm for reader 1 and 4.4 vs 4.6 mm for reader 2, respectively; P > .39 for both readers), in common bile duct area (20.7 vs 21.5 mm², for reader 1 and 21.3 vs 20.2 mm² for reader 2, respectively, P > .60 for both), or in second-order bile duct visualization score (2.34 vs 2.36 for reader 1 and 2.58 vs 2.50 for reader 2, respectively; P > .5 for both).

Conclusion: The results suggest that premedication with intravenous morphine prior to CT cholangiography in potential liver donors does not increase bile duct caliber or improve biliary visualization.

© RSNA, 2008

Materials and Methods: Approval from institutional review board was obtained for this HIPAA-compliant retrospective study; informed consent was waived. The study included all patients (42 men, 52 women; mean age, 61 years) who underwent abdominal 64-detector CT within 2 months of MRCP and/or ERCP. All patients underwent portal venous phase intravenous contrast material–enhanced abdominal CT. Sixty-one patients underwent MRCP and 54 patients underwent ERCP (21 patients underwent both). Two radiologists, blinded to the reference standard, independently evaluated the CT images, including multiplanar and minimum intensity reformations, for biliary duct narrowing and choledocholithiasis. Standard of reference examinations were used to calculate sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

Results: Twenty-three (24%) of 94 patients had a biliary duct narrowing at reference examinations. For detecting biliary duct narrowing, observer 1 had a sensitivity of 78.2%, specificity of 100%, PPV of 100%, and NPV of 93.4% and observer 2 had a sensitivity of 69.6%, specificity of 100%, PPV of 100%, and NPV of 91.0%. In 18 (19%) of 94 patients, choledocholithiasis was detected at reference examinations. For detecting choledocholithiasis, observer 1 had a sensitivity of 77.8%, specificity of 96.1%, PPV of 82.4%, and NPV of 94.8% and observer 2 had a sensitivity of 72.2%, specificity of 96.1%, PPV of 81.2%, and NPV of 93.6%.

Conclusion: Portal venous phase multidetector CT images are highly specific and moderately sensitive for the detection of biliary duct narrowing and choledocholithiasis.

© RSNA, 2008

Materials and Methods: This study was institutional review board approved, and the requirement for informed consent was waived. The imaging, medical, and histopathologic data of 10 patients (seven women, three men; mean age, 38 years) with histopathologically proved adult HD and/or adult HG were reviewed. Two radiologists reviewed 10 transverse computed tomographic (CT) scans and five double-contrast barium enema radiographs in consensus for the presence or absence and the location of the transition zone. The transverse diameter ratio of the most dilated colonic segment proximal to the transition zone to the narrowed colonic segment distal to the transition zone (ie, transition zone ratio), and the longitudinal length of the transition zone were also determined. The CT findings of HD and HG were compared by using the Mann-Whitney U test.

Results: All patients with lifelong or chronic constipation had a transition zone in the upper part of the rectum or rectosigmoid junction (n = 5) or in the descending colon (n = 5) on the CT scans and the double-contrast barium enema radiographs. The transition zone ratio was significantly different between the patients with HD (median ratio, 4.0) and the patients with HG (median ratio, 2.0) (P = .016). However, there was no significant difference in the longitudinal length of the transition zone between the two patient groups (median ratios, 4.4 cm for HD group and 6.0 cm for HG group; P = .190).

Conclusion: A markedly dilated proximal colonic segment with a transition zone and a narrowed distal colonic segment on CT and double-contrast barium enema images in conjunction with chronic refractory constipation in an adult should suggest the diagnosis of adult HD or adult HG. The detection of a much higher transition zone ratio may help to establish the diagnosis of HD.

© RSNA, 2008

Materials and Methods: Investigational review board approval was obtained, and the informed consent requirement was waived. The medical and imaging data of 21 patients (13 men, eight women; mean age, 47.5 years; age range, 25–79 years) with histopathologically proved AIP who underwent contrast material–enhanced CT at diagnosis and after steroid treatment were included in this study. Image analysis included assessment of the (a) presence or absence and type (focal or diffuse) of pancreatic parenchyma enlargement, (b) contrast enhancement of pancreatic parenchyma, (c) size of the main pancreatic duct (MPD) within the lesion and upstream, and (d) pancreatic parenchyma thickness in the head, body, and tail of the pancreas. The same criteria were applied to follow-up CT examinations, the follow-up data were compared with pretreatment data, and a paired sample t test was applied.

Results: Pancreatic parenchyma showed focal enlargement in 14 (67%) patients and diffuse enlargement in seven (33%). Pancreatic parenchyma affected by AIP appeared hypoattenuating in 19 (90%) patients and isoattenuating in two (10%). During the portal venous phase, pancreatic parenchyma showed contrast material retention in 18 (86%) patients and contrast material washout in three (14%). The MPD was never visible within the lesion. After treatment, there was a reduction in the size of pancreatic parenchyma segments affected by AIP (P < .05). Fifteen (71%) of the 21 patients had a normal enhancement pattern in the pancreatic parenchyma, whereas the enhancement pattern remained hypovascular in six (29%). The MPD returned to its normal size within the lesion in all patients at follow-up CT. In one of the eight patients with focal forms of AIP, the upstream MPD remained dilated.

Conclusion: AIP appeared as pancreatic parenchyma enlargement, with MPD stenosis within the lesion and upstream dilatation in focal forms of AIP. After steroid treatment, there was normalization of these findings.

© RSNA, 2008

Materials and Methods: The study had institutional review board approval, and written informed consent was obtained. Ten healthy volunteers (five men, five women; mean age, 24.7 years ± 1.9 [standard deviation]; range, 22–29 years) underwent MR imaging pancreatic perfusion studies performed twice without secretin and twice during secretin stimulation. Dynamic contrast-enhanced MR imaging consisted of saturation-recovery T1-weighted turbo-field-echo imaging with peripheral pulse triggering and respiratory tracking. A dose of 0.05 mmol gadodiamide per kilogram of body weight was injected at a rate of 3.5 mL/sec. Regional perfusion parameters were fitted with a one-compartment model. The analysis of variance test for repeated measurements was used to assess differences in pancreatic perfusion without and that with secretin administration.

Results: Significant differences in perfusion parameters between the three pancreatic regions were observed (P < .05). During secretin stimulation, a significant difference was observed only between the body and the tail of the pancreas (P = .02). A significant increase (P = .003) in pancreatic perfusion was observed after secretin administration. Mean pancreatic perfusion was 184 mL/min/100 g of tissue ± 71, 207 mL/min/100 g ± 77, and 230 mL/min/100 g ± 87 without secretin and 342 mL/min/100 g ± 154, 338 mL/min/100 g ± 156, and 373 mL/min/100 g ± 176 after secretin stimulation in the head, body, and tail of the pancreas, respectively. Intraindividual variability was 21% without secretin stimulation and 46% with secretin stimulation.

Conclusion: Dynamic contrast-enhanced MR imaging enables noninvasive quantification of regional pancreatic perfusion in resting conditions and demonstrates the increase in pancreatic perfusion during secretin stimulation in healthy subjects.

© RSNA, 2008

Materials and Methods: Institutional review board approval and written informed consent were obtained. Patients at increased risk for colorectal cancer underwent CT colonography after fecal tagging, which consisted of 80 mL of barium sulfate and 180 mL of diatrizoate meglumine. Bisacodyl was added for stool softening. A radiologist and a research fellow evaluated all data independently by using a primary two-dimensional approach. Discrepant findings for lesions 6 mm or larger in diameter were solved with consensus. Segmental unblinding was performed. Per-patient sensitivity and specificity, per-polyp sensitivity, and number of false-positive findings were found (for lesions ≥ 6 mm and ≥ 10 mm in diameter). Per-patient sensitivities (blinded colonoscopy vs CT colonography) were tested for significance with McNemar statistics. Interobserver variability was analyzed per segment (prevalence-adjusted bias-adjusted values [_p]).

Results: One hundred fourteen of 168 patients (105 men, 63 women; mean age, 56 years) had polyps, with 56 polyps 6 mm or larger and 17 polyps 10 mm or larger. Per-patient sensitivities were not significantly different for CT colonography (consensus reading) and colonoscopy (P ≥ .070). Sensitivity of CT colonography for patients with lesions 6 mm or larger and 10 mm or larger was 76% and 82%, respectively, and specificity of CT colonography was 79% and 97%, respectively. Blinded colonoscopy depicted 91% (lesions ≥ 6 mm) and 88% (lesions ≥ 10 mm) of disease in patients. Per-polyp sensitivity for CT colonography was 70% (lesions ≥ 6 mm) and 82% (lesions ≥ 10 mm). Number of false-positive findings was 42 (lesions ≥ 6 mm) and six (lesions ≥ 10 mm). _p Was 0.88 (lesions ≥ 6 mm) and 0.96 (lesions ≥ 10 mm).

Conclusion: CT colonography with limited bowel preparation has a sensitivity of 82% and specificity of 97% for patients with polyps 10 mm or larger.

© RSNA, 2008

Materials and Methods: Ethics committee approval and informed consent were obtained for this HIPAA-compliant study. Four readers each read 48 data sets (26 men, 22 women; mean age, 57 years) from a screening population (three containing polyps) without CAD application, followed by review of the CAD output and recorded findings and diagnostic confidence. The 45 data sets that were designated as normal were chosen such that 22 generated 15 or fewer FP CAD marks and 23 generated more than 15 FP CAD marks. Sensitivity, specificity, and receiver operating characteristic (ROC) curves were calculated with and without CAD. The relationships between the number of CAD FP marks and reader confidence, reporting times, and correct data set classification were analyzed by using linear and logistic regression.

Results: Across all readers, CAD resulted in four additional FP detections. Overall reader sensitivity and specificity (6-mm polyp threshold) before and after CAD application were 0.75 (95% confidence interval [CI]: 0.43, 0.95) versus 0.83 (95% CI: 0.52, 0.98) and 0.96 (95% CI: 0.91, 0.98) versus 0.93 (95% CI: 0.88, 0.96), respectively. The area under the ROC curve increased from 0.57 (95% CI: 0.34, 0.80) to 0.61 (95% CI: 0.42, 0.80). There was no correlation between an increasing number of CAD FP marks and reader confidence (P = .71) or correct study classification (P = .23), but there was a positive correlation with CAD-assisted reading times (0.06 [95% CI: 0.02, 0.10], P = .002).

Conclusion: Increasing numbers of CAD FP marks did not adversely influence correct reader study classification or diagnostic confidence, although reporting times did increase.

© RSNA, 2008

Supplemental material: http://radiology.rsnajnls.org/cgi/content/full/2471070816/DC1