The Usefulness of High-Resolution Three-Dimensional Dynamic MR Imaging with Sensitivity Encoding for Evaluating Extrahepatic Bile Duct Cancer

PURPOSE: We assessed the usefulness of high-resolution 3D dynamic MR imaging with sensitivity encoding (mSENSE) for evaluating bile duct cancer. MATERIALS AND METHODS: Twenty-three patients with extrahepatic bile duct cancer underwent multiphasic 3D GRE MRI, including two delayed phases without and with mSENSE. The first delayed phases were obtained with volumetric interpolated breath-hold imaging (VIBE) and then the higher in-plane resolution images (320x168) were obtained using mSENSE. The two delayed phase images were compared quantitatively by measuring the signal-to-noise ratio (SNR) of liver and tumor, the liver-visceral fat contrast and the tumor-visceral fat contrast-to-noise ratio (CNR); the two delayed phase images were compared qualitatively by evaluating the sharpness of the hepatic vessels and bile duct, the artifacts and the conspicuity of bile duct cancer. RESULTS: The quantitative results with mSENSE image were significantly better than those with conventional VIBE. Though the clarity of the intrahepatic vessels and the intrahepatic bile duct, and the artifacts did not differ significantly between the two images (p>0.05), the clarity of the extrahepatic vessels, the extrahepatic bile duct and the bile duct cancer were better on the mSENSE image than on the VIBE (p<0.05). CONCLUSION: The higher in-plane resolution 3D GRE image obtained with mSENSE was of a better image quality than the conventional VIBE images. This technique shows promise for use as a comprehensive exam for assessing bile duct cancer.

Intraluminal Filling Defects of the Bile Ducts: Differentiation of Stones from Tumors-the Value of Magnetic Resonance Cholangiography in Conjunction with a 3D Spoiled Gradient Echo Gadolinium Enhanced Dynamic Sequence

PURPOSE: We wanted to determinate the value of a dynamic volumetric interpolated breath-hold examination (VIBE) as a supplement to MR cholangiography for differentiating biliary stones from tumors when patient are suspected of having intraluminal filling defects on direct cholangiography. MATERIALS AND METHODS: A retrospective analysis was performed for 49 patients who underwent MRI among all the patients who showed intraluminal filling defects on direct cholangiography for evaluating the cause of their jaundice from June 2002 to June 2003. After dividing these patients into two groups, i.e., the group with stones and the group with tumors, we analyzed and compared each MR patterns of 1) signal intensity, 2) shape, and 3) enhancement. RESULTS: High signal intensity on T1-weighted images (p< 0.001, chi-square test), dark signal intensity on T2-weighted images (p< 0.01, Fisher's exact test) or smooth contour of intraluminal filling defects (p< 0.001, chi-square test) could be significantly suggestive findings of stone rather than a tumor mass. Dynamic VIBE is the most specific sequence for differentiating non-enhancing stone from an enhancing mass (p< 0.001, Fisher's exact test). CONCLUSION: We showed that MR cholangiography, when added to the dynamic VIBE sequences, could be an important imaging technique for patients who are suspected of having intraluminal filling defects on direct cholangiography to differentiate stones from tumors. Especially, the addition of dynamic VIBE images can provide the increased level of confidence in the diagnosis.

Usefulness of Magnetic Resonance Cholangiography and Additional T2-Weighted Axial Image in Evaluating Focal Intrahepatic Ductal Dilatation

PURPOSE: To evaluate the value of MR cholangiography (MRC) and MRC with additional T2-weighted axial imaging for evaluating the cause and determining the therapeutic plan in patients with a focal dilatation of the intrahepatic bile ducts(IHBD). MATERIALS AND METHODS: Forty nine patients (male, 27; female, 22; age range, 12-72 (mean, 51) years) with a focal intrahepatic ductal dilatation confirmed surgically and pathologically (lobectomy, 34; biopsy, 7; surgical finding and T-tube cholangiography, 7; percutanous transhepatic biliary drainage with bile cytology, 1) underwent MRC and T2-weighted axial imaging. The MRC were obtained in one of two ways (a single slab or multi-slice acquisition under chemical fat saturation) using RARE (31 patients, source images and single slice images), or TSE (18 patients, source images and MIP reconstruction images). Two radiologists reviewed the MRC images alone, and the MRC images with the T2-weighted axial images. A diagnosis was determined by consensus. RESULTS: In 37 out of 49 patients, the causes of a bile duct dilation were benign diseases (IHBD stones in 33 cases, liver abscesses with IHBD stones in three cases, one inflammatory pseudotumor). Twelve patients had cholangiocarcinomas (mass-forming type in seven cases, intraductal type in three cases, and periductal infiltrating type in two cases). A correct diagnosis was confirmed in 47 out of 49 cases(96.0%), i.e. all the 37 benign lesions and 10 out of 12 malignant lesions. The addition of the T2-weighted axial image to the MRC did not alter the diagnosis of the causes of the focal intrahepatic ductal dilatation, but was helpful in 10 cases (20.4%). Nine cases (7 cholangiocarcinomas and 2 abscesses), in which MRC showed masses, were visualized more definitely on the additional T2-weighted axial images to the MRC than on the MRC alone. The remaining cases were hepatolithiasis, where stones could be easily differentiated from air by the air-fluid level on the axial images. CONCLUSION: MRC is a good diagnostic modality for evaluating a focal dilatation of IHBD, and the addition of T2-weighted axial image to MRC is helpful.

MR Imaging Findings of Clonorchiasis

OBJECTIVE: The purpose of this study was to evaluate the MR spectrum and MR cholangiographic imaging findings of clonorchiasis. MATERIALS AND METHODS: We reviewed 26 patients with confirmed clonorchiasis by either stool tests (n=24) or surgery (n=2). MR imaging was performed on a 1.5 T system (GE Medical Systems, Milwaukee, WI) with a torso coil. Axial T1-and T2-weighted, gadolinium-enhanced dynamic images and MR cholangiography were obtained. Image analyses were used to identify abnormalities of the intrahepatic and extrahepatic bile ducts and the presence of hepatobiliary malignancy. All MR examinations were reviewed by the consensus of two abdominal radiologists. RESULT: Intrahepatic bile duct abnormalities were seen in 23 (89%) of the 26 patients. The most common finding was mild dilatation of the intrahepatic bile duct which was found in 21 (81%). "Too many intrahepatic ducts" were found in 16 (62%), wall enhancement and thickening in 21 (81%) and filling defects and ductal stricture in the intrahepatic bile duct in 6 (24%) and 3 (12%) patients, respectively. Extrahepatic ductal dilation was found in 5 (19%) and 9 (35%) revealed hepatobiliary malignancy. CONCLUSION: MR imaging revealed various findings of clonorchiasis, including dilatation, wall enhancement, stricture of the intrahepatic ducts and filling defect within the intrahepatic bile duct.

Hilar Branching Anatomy of Living Adult Liver Donors: Comparison of T2-MR Cholangiography and Contrast Enhanced T1-MR Cholangiography in Terms of Diagnostic Utility

PURPOSE: To compare T2-weighted MR cholangiography (T2-MRC) and contrast-enhanced T1-weighted MRC (enhanced T1-MRC) in the assessment of biliary anatomy in donor candidates for living related liver transplantation (LRLT). MATERIALS AND METHODS: Thirty-three potential donors underwent MR examination for preoperative evaluation. Using the single-shot half-Fourier RARE sequence, T2-weighted single-section and coronal images were obtained, and enhanced T1-MRC was performed, using 3D GRE sequences after the administration of mangafodifir trisodium. To assess the hilar ductal branching pattern and determine diagnostic confidence, two reviewers first evaluated the unpaired T2-MRC and enhanced T1-MRC images, and then paired T2-MRC and enhanced T1-MRC images together. In particular, in 12 cases in which direct cholangiographys were performed, the feasibility of single duct-to-duct anastomosis was assessed using the unpaired and the paired sets sequentially. RESULTS: The reviewers' confidence tended to be higher for enhanced T1-MRC than T2-MRC, but the difference was not statistically significant. For both reviewers, confidence was significantly higher for the paired set than for T2- or enhanced T1-MRC alone (p < .001). The types of biliary anatomy determined in the paired set matched the consensus reading in 33 (100%) and 30 cases(91%) assessed by reviewer 1 and 2, respectively. The separate interpretation of T2- and enhanced T1-MRC findings matched the consensus interpretation in 30 (91%) and 28 cases (85%), respectively, assessed by reviewer 1, and 26 (79%) and 28 cases (85%), respectively, assessed by reviewer 2. The possibility of single anastomosis was accurately predicted in 91.6% of cases in T2-MRC, and 100% at enhanced T1-MRC and the combined set. CONCLUSION: In the evaluation of the biliary anatomy of potential donors for LRLT, the combined use of T2-MRC and enhanced T1-MRC may improve diagnostic confidence and decrease the occurrence of a non diagnostic or equivocal interpretation at T2-MRC alone.

Usefulness of MR Cholangiography in the Evaluation of Neonatal Cholestasis: Comparison with 99mTc DISIDA Scan

PURPOSE: To evaluate the diagnostic validity of MR cholangiography as a second-line imaging tool following sonography in the evaluation of neonatal cholestasis, we compared MR cholangiography with 99mTc DISIDA scan. MATERIALS AND METHODS: We retrospectively evaluated sonography, 99mTc DISIDA scan and MR cholangiography in twenty-two neonates and infants (age range, 23-103 days; mean age, 57 days) presenting with conjugated hyperbilirubinemia. Of the 22 patients, 15 were diagnosed as biliary atresia by operative cholangiography and liver biopsy and six as neonatal hepatitis by imaging finding and clinical data. Remaining one patient was diagnosed as neonatal hepatitis by operative cholangiography and liver biopsy. Two independent observers for each study were assigned to review the images of 99mTc DISIDA scan and MR cholangiography without giving the final diagnosis or other clinical data. Diagnostic accuracy and interobserver variability for each study were evaluated. RESULTS: On 99mTc DISIDA scan, biliary atresia was mistaken for neonatal hepatitis in eight patients and vice versa in four patients. On MR cholangiography, it was mistaken biliary atresia as neonatal hepatitis and vice versa in each two patients. Sensitivity, specificity, accuracy, positive and negative predictive values of 99mTc DISIDA scan were 48%, 47%, 48%, 66% and 30%, respectively, and those of MR cholangiography were 90%, 71%, 84%, 87% and 81%, respectively. Interobserver variabilities for 99mTc DISIDA scan and MR cholangiography were 0.62 and 0.85, respectively. CONCLUSION: In the evaluation of patients with neonatal cholestasis, it would be advisable to use MR cholangiography, having superior diagnostic accuracy to 99mTc DISIDA scan, as a second-line imaging tool following sonography.

Evaluation of Accuracy and Interobserver Agreement of MR Cholangiography for Diagnosis of Cholelithiasis

PURPOSE: To assess the accuracy of MR cholangiography(MRC) in the diagnosis of cholelithiasis, and to determine interobserver agreement. MATERIALS AND METHODS: Between March and September 1999, 43 consecutive patients with biliary obstruction [24 men and 19 women aged 25 -85 (mean, 58) years] underwent MRC using the single-shot fast spin-echo technique. Heavily T2-weighted source images(axial and coronal) 3 -5 mm thick and 12 projection images with 15- degree rotation and 5-cm thickness were obtained. All images were reviewed blindly and indepen-dently by two radiologists specialized in the interpretation of abdominal imaging information. Choledocholithiasis was evaluated in eight segments of the intrahepatic duct(IHD), extrahepatic duct(EHD) and gall bladder lumen. Final diagnosis was established on the basis of operative (n=31) and other radiological (n=12) findings. The sensitivity, specificity and accuracy of the MRC findings were assessed, and using kappa measurement (cross-table analysis,SPSS Windows for 8.0), interobserver agreement was determined. RESULTS: Thirty of the 43 patients, had choledocholithiasis (IHD stones in 7 cases, EHD stones in 15, and GB stones in 18). For radiologist 1, sensitivity, specificity and accuracy were 86%, 100% and 98%, respectively, in the diagnosis of IHD stones; 100%, 89% and 93%, respectively, in the diagnosis of EHD stones; and 81%, 96% and 91%, respectively, in the diagnosis of GB stones. For radiologist 2, the corresponding figures were 86%, 94% and 93% (1HD stones); 87%, 89% and 88% (EHD stones); and 81%, 86% and 84% (GB stones). Interobserver agreement for the diagnosis of choledocholithiasis was excellent in all cases. The kappa mesurement was 0.91 for 1HD stones, 0.77 for EHD stones, and 0.70 for GB stones. CONCLUSION: MRC is an excellent imaging modality for the diagnosis of choledocholithiasis, and interobserver agreement was also excellent.

Biliary Ascariasis: MR Cholangiography Findings in Two Cases

We describe the imaging features of two cases of biliary ascariasis. Ultrasonography and CT showed no specific abnormal findings, but MR cholangiography clearly demonstrated an intraductal linear filling defect that led to the correct diagnosis. MR cholangiography is thus a useful technique for the diagnosis of biliary ascariasis.

Utility of Single Shot Fast Spin Echo Technique in Evaluating Pancreaticobiliary Diseases : T 2 - weighted Image and Magnetic Resonance Cholangiopancreatography

PURPOSE: To evaluate the accuracy of T2-weighted imaging and MR cholangiopancreatography using the single shot fast spin-echo technique for evaluating pancreaticobiliary disease. MATERIALS AND METHODS: B e t ween March and July 1997, axial and coronal T2-weighted images ( T E : 8 0 -2 00 msec) and MR cholangiopancreatograms(TE:800 -1 2 00 msec) were obtained in two ways [single slab (thickness:30 -50 mm) and multislice acquisition under chemical fat saturation] using SSFSE pulse sequencing in 131 cases of suspected pancreati-cobiliary disease. The accuracy of SSFSE MR imaging was assessed in 89 lesions of 74 patients [male,48; female,26; age range, 3 0 -86 (mean,59)years] confirmed surgicopathologically(50 lesions in 39 patients) and clinically (39 lesions in 35 patients). Two radiologists reviewed the MR images and diagnosis was determined by consensus. RESULTS: Correct diagnosis was confirmed in 84 of 89 lesions (94 %). Seven lesions were falsely interpreted, false positive and false negative results accounting for two and five cases, respective l y. Two pancreatic cancers were misdiagnosed as pancreatitis and a cancer of the proximal common bile duct(CBD) was interpreted as a distal CBD cancer. The sensitivity of SSFSE MR imaging for malignancy was 93 %. One CBD stone revealed by endoscopic retrograde cholangiopancreatography (ERCP) was not detected on MR images. In contrast, a stone in the CBD seen on MR images was not apparent on subsequent ERC P. Sensitivity and specificity for calculous disease were 96 % and 99.7 %, respective l y. A benign stricture of the ampulla of Vater was falsely interpreted as normal, and correct diagnosis was possible in two falsely diagnosed cases when MR images were rev i ewed retrospectively. CONCLUSION: The combination of T2-weighted and cholangiographic images using SSFSE is an accurate method for diagnosing pancreaticobiliary diseases.

Accuracy of MR Imaging for Resectability of Extrahepatic Bile Duct Carcinoma

PURPOSE: To determine the accuracy of preoperative MR imaging for evaluation of resectability of extrahepaticbile duct carcinoma. MATERIALS AND METHODS: Thirty-four patients with proven extrahepatic bile duct carcinomaunderwent pre-operative MR imaging. All MR examinations were performed with a 1.5 T system, using a phased-arraymulticoil. Tumor resectability was prospectively determined by two radiologists who reached consensus. Tenpatients did not undergo surgery because the preoperative MR imaging, CT and endoscopic findings all indicatedunresectability. Twenty-five patients subsequently underwent surgical exploration, and their imaging andpathologic and laparotomic findings were compared. RESULTS: Twenty-two of 34 cases (65%) were resectable. Amongthe 22 cases resectable in laparotomy, pre-operative MR imaging had suggested that 20 were resectable, andsensitivity for resectability was thus 91%. Among the 22 cases in which MR imaging had suggested resectability,macroscopic clearance was complete in 20, giving a positive value of 91%. MR imaging underestimated portal venousor hepatic arterial invasion, and in one case missed small (<1 cm) hepatic metastases. In two cases, MR imagingoverestimated portal venous or hepatic arterial encasement. CONCLUSION: MR imaging is a useful diagnosticmodality for preoperative assessment of resectability of extrahepatic bile duct cancer.

MR Cholangiopancreatography: Comparison of Breath-hold Fast Spin Echo and Respiratory Triggered Fast Spin Echo Techniques

PURPOSE: To determine relative image qualities and to evaluate their ability to visualize biliary trees and pancreatic ducts, we compared the breath-hold fast spin echo (FSE) and respiratory triggered FSE technique in magnetic resonance cholangiopancreatography (MRCP). MATERIALS AND METHODS: Forty-seven patients with suspected of hepatic disease but no pancreatic or biliary ductal dilatation, as determined by other imaging techniques('group of pathologic pancreatobiliary tree') underwent MRCP. Heavily T2-weighted FSE coronal images were obtained by both breath-hold and respiratory triggered techniques. These two images were 3D-reconstructed using a maximal intensity projection algorithm. Three radiologists scored the image qualities of anatomic structures in each set of image, then directly compared the image quality of the images obtained by the two techniques. RESULTS: For the visualization of common hepatic ducts and common bile dvcts, FSE MRCP images obtained using the respiratory-triggered technique were triggered technique were significantly better than those obtained using the breath-hold technique (P<0.05). Fifty-nine to 88% of breath-hold images of the biliary tree and 63-95% of respiratory triggered images were optimal. For the pancreatic duct, however, 24% of breath-hold images and 15% of respiratory-triggered images provided optimal image quality. In direct comparison, respiratory triggered images were better in 25 cases (52.1%), both images were comparable in 12 cases (25.0%), and in 11 cases (22.9%), breath-hold images were better. These differences were statistically significant (p<0.05). CONCLUSION: For the vizualization of extrahepatic bile ducts, the respiratory triggered FSE sequence was better than the breath-hold sequence; for the evaluation of both a non-dilated and dilated pancreatobiliary system, however, both techniques need further development.

MRCP Using Breath-hold HASTE Sequence: Comparison of Maximum Intensity Projection Image with Single Slice Acquisition Image

PURPOSE: To compare the usefulness of single-slice acquisition imaging and conventional maximum intensity projection imaging, as employed in magnetic resonance cholangiopancreatography (MRCP) using the Half-Fourier Acquisition Single Shot Turbo Spin-Echo(HASTE) sequence. MATERIALS AND METHODS: Five healthy volunteers underwent MRCP using the HASTE sequence on a 1.5T MR unit. Two data acquisition techniques were used : 1) single slice acquisition, with 20 mm slice thickness (imaging time, 2 sec), 2) multi-slice acquisition, with 5 mm slice thickness (imaging time, 19 sec), followed by maximum intensity projection reconstruction. Two radiologists independently evaluated the MRCP images obtained using these two techniques; based on the depiction by each of ten anatomic structures, their quality was graded as excellent (3 points), good (2 points), fair(1 point) or poor(0). Mean scores were totalled, and to compare the quality of the two techniques, these scores were compared. Data was statistically analyzed using the paired student t-test. RESULTS: There was no difference in bile duct image quality between the two techniques. The pancreatic duct was more conspicuous on single-slice (mean score, 1.94) than on maximum intensity projection imaging (mean score, 0.7). The sum of the mean scores of single-slice imaging was 18.75, and that of maximum intensity projection imaging was 14.7 (p=0.42); the general difference between the two techniques was thus statistically insignificant. CONCLUSION: Compared with maximum intensity projection imaging, single-slice imaging had a distinct advantage : acquisition time was short (within 2 sec), thus motion artifacts could be avoided, and there was no need for post-processing. There is a close and direct connection between the avoidance of motion artifact and short acquisition time, but lack of need for post-processing is independent. On single-slice images, the pancreatic duct was more conspicuous than on maximum intensity projection images. The former can therefore be used with patients who experience respiratory difficulty or are suspected to be suffering from disease of the pancreotic duct.

Non-breath-hold MR Cholangiography for the Evaluation of Obstructive Biliary Diseases

PURPOSE: MR cholangiography(MRC) in patients with obstructive biliary diseases was evaluated in order to compare its role with that of ERCP or PTC. MATERIALS AND METHODS: Twenty consecutive patients with obstructive biliary and peribiliary diseases (Eleven biliary and peribiliary carcinomas, seven intrahepatic stone diseases and seven extrahepatic stone diseases) were included and ERCP(16 ccases) or PTC(four cases) was performed in all twenty cases. Non-breasth-hold, heavily T2-weighted, fast spin echo MRC was carried out and 2-D axial, coronal images and 3-D images with maximum intensity projection protocol were obtained. We regarded ERCP or PTC as thegold standard and then comparedn MRC with ERCP of PTC retrospectively. RESULTS: In 11 patients with biliary and peribiliary carcinomas, the level of obstruction was depicted in nine cases(83%) on MRC and in six of seven cases(86%) on ERCP. The causes of obstruction were demonstrated in eight cases(73%) on MRC and in six of seven cases(86%) on ERCP. On MRC, Seven cases(64%) revealed similar findings to ERCP or PTC. Of seven cases of EHD and seven of IHD stone diseases, EHD stones were detected in six cases(86%) on MRC and in seven cases (100%) on ERCP,IHD stones were detected in four cases(57%) on MRC and in five cases(71%) on ERCP. 2D-MRC was superior to 3D-MRCin the detection of stones. The extent and grade of ductal dilatiation was accurately revealed in six cases(86%)on MRC and in seven cases(100%) on ERCP of EHD stones, in six cases(86%) on MRC and in three cases(43%) on ERCP of IHD stones. Six cases(86%) of EHD stones and two cases(29%) of IHD stones revealed similar findings between MRCand ERCP. CONCLUSION: MRC findings were similar to those of ERCP or PTC in the evaluation of malignant biliary diseases or extrahepatic stone diseases and was valuable in their diagnoses. In the evaluation of intrahepaticstone diseases, MRC demonstrated dilated peripheral IHDs with stones more difinitely than ERCP but in the detection its accuracy was low. Further studies may therefore be needed.