Pancreaticobiliary Juice Reflux in Patients With a Morphologically Normal Ductal System: Assessment Using Unenhanced MRI With Spin Labeling.

OBJECTIVE: The purpose of this article is to evaluate pancreaticobiliary reflux and to assess its correlation with clinical findings in patients without morphologic pancreaticobiliary maljunction by using a new MRI technique. MATERIALS AND METHODS: A total of 320 consecutive patients with suspected pancreaticobiliary diseases underwent MRCP and flow analysis by MRI. MRI flow analysis, clinical, and laboratory findings of each patient were retrospectively reviewed. The visible pancreaticobiliary reflux was graded on a 5-point confidence scale. RESULTS: Among all 320 patients with pancreatic juice reflux, 14.1% had reflux scored as grades 4 and 5 combined, and 5.0% had reflux scored as grade 5. By univariate analysis and multivariate analysis, a relatively long common channel was found to be the only significant causal factor for pancreatic juice reflux. Of patients with pancreatic juice reflux of grade 4 or 5, 11.1% (5/45) also had biliary malignancies; 18.8% (3/16) of those with pancreatic juice reflux of grade 5 had biliary malignancies. Conversely, pancreatic juice reflux of grade 4 or 5 occurred in 35.7% (5/14) of patients with biliary malignancies, and reflux of grade 5 occurred in 21.4% (3/14) of those patients. CONCLUSION: It was possible to evaluate pancreaticobiliary reflux using an MRI technique that may be suitable as a screening tool. Our results revealed that pancreaticobiliary reflux is relatively frequent in individuals without pancreaticobiliary maljunction.

Direct visualization of pancreatic juice flow using unenhanced MRI with spin labeling can be aid in diagnosing chronic pancreatitis.

OBJECTIVE: The purpose of this study is to prospectively assess whether direct visualization of pancreatic juice flow using an unenhanced MRI technique with spin labeling can aid in the diagnosis of chronic pancreatitis. SUBJECTS AND METHODS: Ten healthy volunteers and 50 patients who were categorized as having no chronic pancreatitis (n = 11), early chronic pancreatitis (n = 7), or established chronic pancreatitis (n = 32) underwent MRI, including direct pancreatic juice visualization using a flow-out technique with a time-spatial labeling inversion pulse, comprising a nonselective inversion recovery pulse immediately followed by a spatially selective inversion labeling pulse. The mean velocities and volumes of pancreatic juice excretion were also obtained. Variance tests were used to evaluate the clinical groups with respect to the appearance rate and mean velocity; the Kruskal-Wallis test was used for volume. RESULTS: There were no significant differences between healthy volunteers and patients with no chronic pancreatitis. The appearance rate, mean velocity, and volume of pancreatic juice excretion tended to decrease with the degree of chronic pancreatitis. Although the difference in these values was statistically significant between the healthy group and the established chronic pancreatitis group, the values of the early group and other groups were not statistically significant. There was a significant correlation between the appearance rate of pancreatic juice and the clinical groups (τ = -0.4376, p = 0.0015). CONCLUSION: The measurement of directly visualized pancreatic juice flow may aid in establishing the diagnosis of chronic pancreatitis.

Visualization of pancreatic juice movement using unenhanced MR imaging with spin labeling: preliminary results in normal and pathophysiologic conditions.

PURPOSE: To visualize the movement of pancreatic juice noninvasively by using an unenhanced magnetic resonance (MR) imaging technique. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained for this study. A flow-out technique of time-spatial labeling inversion pulse (SLIP) technique was applied using both nonselective and selective inversion pulses to label, or tag, pancreatic juice to move out of the region. Ten normal (eight men, two women; age range, 22-61 years; mean age, 35 years) and two pathologic conditions were examined on a commercially available 1.5 Tesla MR imager with quadrature-detected phased-array coils. All images were evaluated by two radiologists to assess depiction of the pancreatic juice movement or pancreatic juice reflux as compared to the pancreatic duct or the common bile duct on MRCP obtained before time-SLIP examination. RESULTS: The tagged pancreatic juice was satisfactory visualized after applying the pulse labeling. Noninvasive visualization of pancreatic juice movement, including normal pancreatic juice movement and reflux from the main pancreatic duct into the common bile duct, was possible by using the unenhanced time-SLIP technique. CONCLUSION: Noninvasive visualization of pancreatic juice movement is possible by using the unenhanced MR imaging time-SLIP technique.

High b-value diffusion-weighted MRI for detecting gallbladder carcinoma: preliminary study and results.

The aim of this preliminary study was to retrospectively evaluate the usefulness of high b-value diffusion-weighted MR imaging (DWI) in the detection of gallbladder carcinoma. Fifteen patients with gallbladder carcinoma and 14 other patients were included in this study. All patients and subjects underwent DWI, and images were evaluated by two radiologists. The area under the receiver operating characteristic curve (AUC), apparent diffusion coefficient (ADC) measurement, sensitivity and specificity were calculated. An AUC yielded 0.980 (95% CI, 0.850-0.999) and 0.941 (95% CI, 0.791-0.990) for the two radiologists. The mean sensitivity and specificity were 83.3% and 100%, respectively. The mean ADC value of gallbladder carcinoma was (1.28 +/- 0.41)x10(-3) mm(2)/s and that of control gallbladder lesions was (1.92 +/- 0.21)x10(-3) mm(2)/s (P < 0.01). According to the results of our preliminary study, high b-value DWI might be a useful tool for detecting gallbladder carcinoma by measuring the ADC value and direct visual assessment.

Periampullary tumors: high-spatial-resolution MR imaging and histopathologic findings in ampullary region specimens.

PURPOSE: To prospectively determine the magnetic resonance (MR) signal intensity characteristics of structures of the ampullary region and to assess the potential use of MR imaging in evaluation of the extent of periampullary tumors in resected specimens. MATERIALS AND METHODS: Twenty-five specimens from the ampullary region obtained in four autopsy cases without periampullary tumors and in 21 patients with periampullary tumors were examined with a 1.5-T MR system and a circular surface coil with 5-inch (12.7-cm) diameter. High-spatial-resolution MR images were obtained with field of view of 100 x 100 mm, matrix of 256 x 256 or 512 x 256, and section thickness of 2 mm. MR imaging findings were compared with histopathologic findings. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of high-spatial-resolution MR imaging for assessment of tumor invasion into surrounding tissues were evaluated by two radiologists. RESULTS: T1- and T2-weighted MR images clearly depicted normal structures in the ampullary region that included Oddi muscle, duodenal wall, common bile duct, and pancreas; these findings corresponded well with histologic findings. In 20 (95%) of 21 tumors, high-spatial-resolution MR imaging depicted location and extension of periampullary tumors precisely. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of high-spatial-resolution MR imaging for assessment of tumor invasion into surrounding tissue were 88%, 100%, 96%, 100%, and 94%, respectively. CONCLUSION: In this study, MR imaging correctly depicted location, extension, and origin of tumor. High-spatial-resolution MR imaging has potential for presurgical staging of tumors in this region.