MR Virtual Endoscopy for Biliary Tract and Pancreatic Duct

Abstract

Developments in magnetic resonance (MR) equipment and techniques have been remarkable. Especially, respiratory-triggered three-dimensional MR cholangiopancreatography (3D-MRCP) has been developed to provide images with high spatial resolution of the biliary tract and pancreatic duct. These 3D data can be employed in MR virtual endoscopy (MRVE) with volume rendering to visualize the lumina of the gallbladder, bile duct, and pancreatic duct. To observe the changes in the lumina with threshold settings on a workstation, we made an original phantom with tubes 2, 3, and 6 mm in internal diameter. We examined the changes in luminal diameter using several threshold settings by comparing the actual internal diameters to determine an appropriate threshold setting, which we then applied in 50 clinical cases, including pancreatic tumors, hepatic tumors, and biliary tract stones. We obtained MRVE images of the gallbladder, bile duct, and pancreatic duct to assess the clinical usefulness of this method. In the phantom study, a value identical to the actual luminal diameter could be obtained with a threshold of less than 20z. In all clinical cases, we obtained MRVE images of the gallbladder, bile duct, and pancreatic duct using the threshold we had determined appropriate and scored the diagnostic usefulness in each region. The MRVE images of the biliary tract provided much supplementary information, including the presence of stones and of duct invasion by the malignancy as wells as visualization of the post-stenotic portion. MRVE images of the gall bladder did not signiˆcantly improve diagnosis (P＝0.311), but those of the bile and pancreatic ducts did (Pº0.05). In addition, MRVE may aid navigation during cholangioscopy. Thus, MRVE is a clinically useful technique for examining lesions of the biliary tract and pancreas.

MR Virtual Endoscopy of the Fetal Limb Anomalies Using Three-Dimensional Fast Imaging Employing Steady-State Acquisition Sequence

“…The virtual MR endoscopic technique is used to gain an image display by the processing of 3D data sets to provide a simulated visualization of a patient's hollow organs similar to that produced by using standard endoscopes; meanwhile, the total processing was not time-consuming [10]. Studies have described clinical applications of virtual endoscopy to visualize the inside of the cerebellopontine angle [11], shoulder [12], biliary tract and pancreatic duct [13], and urinary tract [14]. To our knowledge, there is no large series in the literature related to virtual MR endoscopy application in the fetus [15,16].…”

Utilization of a new technology of 3D biliary CT for ERCP-related procedures: a case report

“…Reports have indicated that it has contributed to shortening the procedure time, improving the procedure success rate, and reducing the incidence of complications. Respiratorytriggered three-dimensional MR cholangiopancreatography (3D-MRCP) provides high-spatial-resolution images of the biliary tract and pancreatic duct, and enables MR virtual endoscopy using volume rendering to visualize the lumens of the gallbladder, bile duct, and pancreatic duct [6]. However, the utility of 3D-CT image in ERCPrelated procedures has not been reported.…”

Intravascular virtual MR endoscopy evaluation of cerebral aneurysms

“…Studies have described clinical applications of virtual endoscopy to visualize the inside of the bronchi, paranasal sinus, stomach, bladder, small intestine, pancreatic duct, bile duct, and spine (2,6,8,10,11,16,19,21,23,24). Shigematsu et al (20) reported the use of virtual intravascular MR endoscopy for aneurysms in three cases.…”

“…Studies have described clinical applications of virtual endoscopy to visualize the inside of the tracheobronchial tree, paranasal sinus, stomach, bladder, small intestine, pancreatic duct, bile duct, and spine (2,(6)(7)(8)10,11,16,19,21,23,24). Virtual endoscopy used for preoperative planning in neurosurgery for endoscopic third ventriculostomy, nasal cavity and paranasal sinus surgery, and virtual endoscopy visualization of the sphenoid sinus and important adjacent structures is valuable for training and the preoperative planning of endonasal transsphenoidal surgery (15).…”

“…All patients were scanned using a 1.5T scanner (Siemens Magnetom Symphony Quantum, Erlangen, Germany). Data recorded included 3D time-of-flight (3D TOF) MRA protocol, echo time (19 ms), repetition time (5.7 ms), flip angle (16°), the number of signal averages (2), field of view (18 cm), slice thickness (1 mm), and matrix dimensions (230×256).…”