Using CT and cholangiography to diagnose biliary tract carcinoma complicating primary sclerosing cholangitis.

OBJECTIVE: The objective of our study was to determine the value of CT and cholangiography for diagnosing biliary tract carcinoma complicating primary sclerosing cholangitis. MATERIALS AND METHODS: One hundred thirteen abdominal CT examinations and cholangiograms in 45 patients with primary sclerosing cholangitis, including 18 patients with established biliary tract carcinoma, were analyzed for tumor. Four radiologists who were unaware of the presence or absence of carcinoma rated each study as to the probability of malignancy. Receiver operating characteristic curve analysis was used to assess the diagnostic performance of CT and cholangiography, the value of imaging signs, and the degree of inter-observer variation in interpretation. Sensitivity and specificity values were calculated. RESULTS: CT outperformed cholangiography in the detection of carcinoma. The average area under the receiver operating characteristic curve was 0.82 for CT and 0.57 for cholangiography (p = 0.003). Sensitivity and specificity for detecting carcinoma using CT were good, with average values of 82% and 80%, respectively. Average sensitivity and specificity for cholangiography were 54% and 53%, respectively. The most reliable sign of tumor on CT was a discrete mass. Progressive biliary dilatation on sequential studies was the most useful sign on cholangiography. Interobserver agreement assessed using the Cronbach alpha was fair for cholangiography and good for CT. CONCLUSION: CT provides good sensitivity and specificity and significantly outperforms cholangiography in detecting biliary tract carcinoma complicating primary sclerosing cholangitis. Despite limitations, CT and cholangiography provide useful information not otherwise available in the treatment of patients with primary sclerosing cholangitis.

A rapid method for determining the tuberculocidal activity of liquid chemical germicides.

A rapid, quantitative method has been developed for determining the tuberculocidal activity of liquid chemical germicides. In this method, a test strain of Mycobacterium bovis that carries the firefly luciferase gene is exposed to a germicide, and the surviving bacteria are detected by bioluminescence. The tuberculocidal activities of five commercially available glutaraldehyde-based disinfectants were tested, and all reduced the number of surviving mycobacteria by greater than five orders of magnitude. In contrast, a phenol-based disinfectant with tuberculocidal claims gave less than one order of magnitude reduction of the test organism. With this method for determining tuberculocidal activity, results can be obtained in less than one day, compared with weeks or months for the standard tuberculocidal assays.

Effects of luminance and resolution on observer performance with chest radiographs.

PURPOSE: To examine the combined effects of image resolution and display luminance on observer performance for detection of abnormalities depicted on posteroanterior chest radiographs. MATERIALS AND METHODS: A total of 529 radiographs were displayed on a specially constructed view box at three luminance levels (770, 260, and 85 cd/m(2)) and three resolutions (100-microm, 200-microm, and 400-microm pixels). Each image was reviewed nine times by six radiologists who participated in this study. The abnormalities included nodule, pneumothorax, interstitial disease, alveolar infiltrates, and rib fracture. Negative (normal) radiographs were also included. RESULTS: Receiver operating characteristic curves indicated that the effect of image luminance was greater than that of resolution. The detection of pneumothorax, interstitial disease, and rib fracture showed statistically significant differences (P <. 05) due to luminance. The detection of pneumothorax was the only abnormality with a statistically significant difference due to resolution. There was no evidence that luminance was related to image resolution for any of the abnormalities. CONCLUSION: At a resolution of 400-microm pixels or higher across the field of view and a luminance of 260 cd/m(2) or more, primary diagnosis with posteroanterior chest radiographs is not likely to be affected by the quality of display.

Diagnosis of mouse hepatitis virus contamination in mouse population by using nude mice and RT-PCR.

Mouse hepatitis virus (MHV) infection in laboratory mouse populations is a serious problem, because the MHV infections are known to interfere with research results. Confirmation of indirect serological detection methods by viral isolation is difficult. Reverse transcription plus polymerase chain reaction (RT-PCR) was used to test 94 mouse tissue samples from suspected naturally MHV infected mice. Positive results were only obtained from two colon samples and one mixed sample with colon and liver. The low positive rate is probably due to the virus being rapidly cleared by the MHV antibodies produced in the mouse. However, RT-PCR detection of MHV in nude mice placed in the same cages with other non-nude mice or placed in cages with used dirty bedding, showed a very high positive rate: 10 out of 12 colon samples were positive (83%), and 5 out of 10 faecal samples were positive (50%). A single-tube, single step RT-PCR method and two procedures for isolation of the viral RNA for the RT-PCR assay were also included in this article.

Empiric assessment of parameters that affect the design of multireader receiver operating characteristic studies.

RATIONALE AND OBJECTIVES: The authors attempted to assess experimentally the magnitude of reader variability and the correlations and interactions among cases, readers, and modalities during observer performance studies and their possible effects on study design and sample size. MATERIALS AND METHODS: Published data from 32 selected receiver operating characteristic (ROC) studies were reviewed to compare the magnitude of the variance component from readers with the variance component from modality. Estimates of correlation and interactions among cases, readers, and modalities were also computed directly from ROC data ascertained during two large studies performed in our laboratory. Each of these two studies included 529 cases and six readers, but one study used eight modalities and the other nine. RESULTS: Published results indicate that reader variability is task dependent and larger (P < .05) than modality variability in detection of interstitial disease. Measured correlations between modalities for the same reader were task dependent and ranged from 0.35 to 0.59. Modality-by-reader and modality-by-case interactions often are not important factors. The random error term was greater than the modality-by-reader interaction in 11 of 20 comparisons and greater than the modality-by-case interaction in eight of 20 comparisons. CONCLUSION: Use of the same cases interpreted with different modes is justifiable in many situations because of the high variability from readers. This comprehensive review of existing ROC studies resulted in parameter assessments that can be used to better estimate sample-size requirements in multireader ROC studies.

Biliary tract carcinoma complicating primary sclerosing cholangitis: evaluation with CT, cholangiography, US, and MR imaging.

PURPOSE: To assess the value of computed tomography (CT), cholangiography, ultrasonography (US), and magnetic resonance (MR) imaging in the demonstration of biliary tract carcinoma complicating primary sclerosing cholangitis (PSC). MATERIALS AND METHODS: Thirty patients were studied who had PSC and biliary tract carcinoma. Twenty-six patients had cholangiocarcinoma, and four had gallbladder carcinoma. Sixty-four CT scans, 41 cholangiograms, 40 US studies, and seven MR studies were reviewed retrospectively for evidence of tumor and PSC. Imaging results were correlated with pathologic findings from whole liver specimens and biopsies. Presence of mass was rated as definite, probable, possible, or doubtful or absent. RESULTS: On CT scans, cholangiocarcinomas produced hypoattenuating masses in 17 of 23 cases, delayed contrast enhancement in six of 12, progressive biliary dilatation in five of 15, and thickened bile duct wall in two of 23. On cholangiograms, dominant strictures were present in 18 of 21 cases of cholangiocarcinoma; 13 were malignant, and five were benign. Cholangiocarcinoma formed polypoid bile duct masses in two of 21 cases. Biliary dilatation was caused by cholangiocarcinoma in 10 of 12 cases and by benign stricture in two. Gallbladder carcinomas demonstrated masses on CT scans, cholangiograms, and US images, and wall thickening on CT and US images. Overall, definite or probable tumor was demonstrated in 25 of 30 patients (83%). CONCLUSION: Most biliary tract carcinomas complicating PSC can be demonstrated on imaging studies.

Bile duct calculi in patients with primary sclerosing cholangitis.

PURPOSE: To determine the imaging appearance and frequency of detection of bile duct calculi in patients with primary sclerosing cholangitis. MATERIALS AND METHODS: Images (169 computed tomographic [CT] scans, 155 sonograms, and 109 cholangiograms) of 189 patients with primary sclerosing cholangitis, five of whom were prospectively included, were reviewed. Pathologic records were reviewed for proof of the presence of calculi. RESULTS: Bile duct calculi were visualized on images in 14 (7.6%) of the 184 retrospective patients and in all five of the prospective patients. The presence of calculi was confirmed with pathologic or imaging findings in 19 patients, in whom calculi were visible on 16 of 18 CT scans, 15 of 19 sonograms, and 14 of 17 cholangiograms. Calculi were in the intrahepatic ducts in 11 patients and in the intra- and extrahepatic bile ducts in eight patients. At CT, calculi appeared as foci of faint high attenuation or as coarse calcifications in nondilated or variably dilated ducts. At sonography, they appeared as unique echogenic casts with variable posterior acoustic shadowing or as discrete, echogenic, variably shadowing foci in variably dilated ducts. Calculi were depicted at cholangiography as rounded filling defects. CONCLUSION: Intrahepatic bile duct calculi are present in approximately 8% of patients and can have a unique imaging appearance.

Cholangiographic features of biliary strictures after liver transplantation for primary sclerosing cholangitis: evidence of recurrent disease.

OBJECTIVE: Biliary strictures occur more frequently after liver transplantation for primary sclerosing cholangitis (PSC) than for other diseases. A hypothesized cause is recurrence of PSC in the liver graft. In our study, we compared cholangiographic features of biliary strictures after transplantation for PSC to those after transplantation for other diseases. MATERIALS AND METHODS: A study group of 32 PSC grafts in adults with biliary strictures was compared with a control group of 32 non-PSC grafts with strictures. Both groups were matched for the type of biliary anastomosis (choledochojejunostomy) and for the time interval between transplantation and stricture diagnosis. We then performed a blind retrospective review of cholangiograms in these 64 cases to evaluate for features of PSC. RESULTS: Location, number, and length of strictures and ductal dilatation were similar in the PSC and non-PSC groups. Mural irregularities of bile ducts were present in 15 of 32 (47%) PSC grafts compared with four of 32 (13%) in the control group (p=.005). Diverticulum-like outpouchings occurred in six of 32 (19%) PSC graft compared with one of 32 (3%) in the control group. An overall resemblance to PSC was observed in eight of 32 (25%) grafts in the PSC group compared with two of 32 (6%) in the control group. CONCLUSION: Mural irregularity and diverticulum-like outpouchings--findings suggestive of PSC--and an overall appearance resembling PSC occur more frequently in PSC transplants than in transplants for other diseases. These findings are consistent with the hypothesis that PSC may recur in liver transplants.

Biliary stones and sludge in liver transplant patients: a 13-year experience.

PURPOSE: To determine the prevalence, radiologic features, and clinical significance of bile duct filling defects (BDFDs) in liver transplant recipients studied with cholangiography. MATERIALS AND METHODS: During 13 years, 4,100 cholangiograms were obtained in 1,650 patients. All studies showing BDFD suggestive of stones, sludge, cast, or necrotic debris were retrospectively evaluated. RESULTS: The prevalence of BDFD was 5.7% (n = 94). On the basis of cholangiographic appearance, BDFDs were categorized as sludge or cast in 53 grafts (56%), stones in 32 (34%), and necrotic debris in nine (10%). Forty-three patients (46%) underwent surgical biliary reconstruction, while 14 (15%) underwent interventional radiologic treatments. Twenty-four of 32 stones (75%) were treated with surgical reconstruction, compared with 31% (19 of 62 grafts) of other BDFDs (P < .0001). Necrotic debris and sludge were associated with hepatic artery occlusion in seven of nine (78%) and 16 of 53 (30%) grafts, respectively. CONCLUSION: Stones and sludge are relatively infrequent after liver transplantation but are associated with high morbidity. Surgical or interventional radiologic treatments are usually performed. Bile duct stones are usually treated with surgical biliary reconstruction. While debris and bile duct necrosis are due to ischemia from hepatic artery occlusion, sludge may also have an ischemic pathogenesis in some cases.

Imaging findings in Caroli's disease.

In 1958 Jacques Caroli described communicating cavernous ectasia of the biliary tree as an uncommon cause of chronic, often life-threatening hepatobiliary disease. The disease now most often referred to as Caroli's disease is a rare condition characterized by nonobstructive saccular or fusiform dilatation of the intrahepatic bile ducts. In the so-called pure form, dilatation is classically segmental and saccular and is associated with stone formation and recurrent bacterial cholangitis. In the form associated with congenital hepatic fibrosis, bile duct dilatation usually is less prominent; portal hypertension and eventual liver failure typically develop as a result of the hepatic fibrosis. Caroli's disease usually is manifested in childhood and is thought to be congenital and probably inherited. Associated conditions include renal cystic disease, choledochal cysts, and cholangiocarcinoma. This pictorial essay illustrates the broad spectrum of imaging findings in Caroli's disease.

Evaluation of the transplanted liver and postoperative complications.

This article presents a brief review of posthepatic transplantation anatomy and a synopsis of the role of imaging in posthepatic transplantation complications. Screening ultrasonography is used to detect vascular stenosis or occlusion. T-tube cholangiography is used to detect biliary leak or obstruction. Thoughtful use of conventional radiographs, ultrasonography, CT, percutaneous cholangiography, and MR imaging for problem solving in detection and management of complications, such as abdominal fluid collections, can make the difference between graft survival or failure.

Intestinal and multivisceral transplantation.

Intestinal transplantation for treatment of irreversible intestinal failure is the newest of the transplantation operations to be developed for clinical use. Because the bowel is more vulnerable to rejection than heart, lung, kidney, liver, or pancreas, practical clinical intestinal transplantation has been relatively slow to develop and is still in its infancy. Imaging studies play an important role in the initial evaluation of the residual native gastrointestinal tract for patients who are potential candidates for enteric implant. After transplantation, gastrointestinal contrast studies help monitor the recovery of gastrointestinal function and permit early detection of postoperative technical complications. CT, ultrasound, and angiography are useful for diagnosis and in some cases treatment of a variety of posttransplantation complications.

Amelioration of intestinal dysmotility and stasis by octreotide early after small-bowel autotransplantation in dogs.

BACKGROUND: Intestinal dysmotility and stasis after intestinal transplantation are considered to promote bacterial overgrowth and translocation. Two prokinetic agents, KW5139 (13-leu-motilin) and the somatostatin analogue octreotide acetate, were studied to determine whether they can ameliorate intestinal dysmotility during the early postoperative period. MATERIALS AND METHODS: Motility was recorded by multiple extraluminal strain-gauge transducers in 6 dogs on postoperative days 1, 3, 7, and 14. A barium meal study was performed with a separate group of 8 dogs on postoperative days 3 and 7. RESULTS: The agent KW5139 induced brief, weak contractions in the graft and had little effect on the dilated bowel; however, octreotide induced motor activity that propelled accumulated intestinal contents into the colon and reduced dilation of the transplanted bowel. CONCLUSION: Octreotide, but not KW5139, ameliorates intestinal dysmotility associated with bowel autotransplantation during the early postoperative period. Short-term administration of octreotide may be useful for the treatment of dysmotility following intestinal transplantation.

The use of PCR to monitor the population abundance of six human intestinal bacterial species in an in vitro semicontinuous culture system.

Six PCR primer sets complementary to the 16S rDNAs (rRNA genes) were developed and shown to be specific for the following anaerobic bacteria: Clostridium clostridiiforme, C. perfringens, C. leptum, Bacteroides vulgatus, B. distasonis, and B. thetaiotaomicron, respectively. These primers were used for PCR to detect and monitor the bacteria in a semicontinuous culture system designed to mimic intestinal microflora in the human gastrointestinal tract. Except for C. perfringens, the five species of Bacteroides and Clostridia present in the in vitro culture system were detected by the PCR, and the titers varied from 10(-2) to 10(-6) dilutions. The role of azo dye reduction by these bacterial species in the system was examined and discussed.

Bile leak after hepatic transplantation: cholangiographic features, prevalence, and clinical outcome.

PURPOSE: To evaluate cholangiographic features and prevalence of bile duct leaks in liver transplant recipients and correlate the different types of leaks with clinical outcomes. MATERIALS AND METHODS: For 6 years, 3,242 cholangiograms were obtained in 1,363 liver allografts in 1,306 patients. All cholangiograms with definite or suspected bile duct leaks, per the radiology reports, were retrospectively reviewed. RESULTS: Leaks were diagnosed in 59 allografts in 59 patients. The prevalence of leaks after liver transplantation, as depicted on cholangiograms, was 4.3% (59 of 1,363 grafts). Sixteen of 21 patients with anastomotic leaks needed 17 surgical repairs, four leaks were surgically drained without repair, and one was treated with percutaneous biliary catheter drainage. Twelve of 21 patients with T-tube exit-site leaks underwent T-tube drainage. Seven underwent surgical repair or drainage, one died, and one underwent retransplantation. Nine of 13 patients with leaks from bile duct necrosis required retransplantation. CONCLUSION: Bile duct leaks at biliary anastomoses and those resulting from bile duct necrosis have high morbidity, mortality, and graft loss rates and usually require surgical intervention. Most T-tube exit-site leaks heal with conservative treatment.

Intrahepatic biliary strictures after liver transplantation.

PURPOSE: To evaluate the prevalence, cholangiographic features, causes, and management of intrahepatic biliary strictures in hepatic transplants. MATERIALS AND METHODS: Over a 12-year period, cholangiography was performed in 1,590 liver allografts. Confirmed cases of stricture were evaluated and correlated with clinical variables. RESULTS: Intrahepatic biliary strictures occurred in 130 of 1,590 grafts (8.2%). Strictures were multiple in 99 grafts (76.2%) and single in 31 (23.8%). Locations were the common hepatic duct bifurcation in 46 grafts (35.4%), the peripheral ducts in 44 (33.8%), and both in 40 (30.8%). Strictures caused mild to moderate bile duct dilatation in 72 grafts (55.4%), marked dilatation in 11 (8.5%), and obstruction in four (3.1%). Hepatic artery occlusion, pretransplantation primary sclerosing cholangitis, choledochojejunostomy, use of Euro-Collins organ preservation solution, cholangitis at liver biopsy, and young age were statistically significantly associated with strictures (P < .001). CONCLUSION: Strictures have multiple causes and may be an important indicator of underlying abnormalities. They often require interventional radiologic or surgical treatment.

Sequential viewing of abdominal CT images at varying rates.

PURPOSE: To evaluate radiologists' ability to detect abdominal masses during sequential viewing of series of computed tomographic (CT) scans at varying rates. MATERIALS AND METHODS: Receiver operating characteristic (ROC) analysis was used to assess the ability of five experienced radiologists to determine the presence or absence of subtle abdominal masses in 29 cases (15 positive, 14 negative) while viewing CT scans sequentially at different rates (0.5, 1, 2, 4, 7, and 21 images per second) and also at reader-selectable rates. RESULTS: Even at extremely fast viewing rates (21 images per second), radiologists performed significantly better (P < .05) than would be expected by chance alone (average area Az under the ROC curve = 0.73 vs 0.5). As the viewing rate decreased, their performance increased. The reader-selectable mode was better than any fixed-rate cine mode (average Az = 0.93). CONCLUSION: Fixed-rate sequential viewing of CT images for the primary diagnosis of subtle abdominal masses should be restricted to no more than one or two images per second, but the reader-selectable viewing mode is preferable to any fixed-rate cine mode.

Digital radiography and conventional imaging of the chest: a comparison of observer performance.

OBJECTIVE: The purpose of this study was to compare observer performance in interpreting high-quality, digitally acquired computed radiographs of the chest displayed on either laser-printed radiographs or a workstation with observer performance in interpreting conventional chest radiographs. SUBJECTS AND METHODS: We performed a receiver-operating-characteristic study in which the presence or absence of five abnormalities was determined by nine experienced radiologists on 310 posteroanterior radiographs of the chest displayed in three forms: conventional radiographs, laser-printed films of digital radiographs, and digital radiographs on a high-resolution workstation. RESULTS: The results of our study suggest that observer performance with laser-printed films of digital radiographs obtained with high-resolution (4K x 5K), high-contrast sensitivity (12 bits) and appropriate exposure is comparable to observer performance with conventional radiographs. Observer performance with digital radiographs displayed on the workstation was found to be significantly lower for abnormalities that contained high-frequency and low-contrast information (e.g., interstitial disease and pneumothorax). CONCLUSION: Computed radiography technology can produce image quality that is adequate for interpreting posteroanterior radiographs of the chest. Observer performance is not as good when radiographs displayed on workstations are used to diagnose specific abnormalities.