Azuma Toshiya, Yamaguchi Kenichiro, Iida Tomojiro, Oouhida Jiro, Suzuki Masayuki
Department of Radiological Technology, Miyazaki University School of Medicine, Kiyotake, Miyazaki, Japan.
Magn Reson Med Sci. 2007;6(4):249-57. doi: 10.2463/mrms.6.249.
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 20%. 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 significantly improve diagnosis (P=0.311), but those of the bile and pancreatic ducts did (P<0.05). In addition, MRVE may aid navigation during cholangioscopy. Thus, MRVE is a clinically useful technique for examining lesions of the biliary tract and pancreas.
磁共振（MR）设备和技术取得了显著进展。特别是，呼吸触发三维磁共振胰胆管造影（3D-MRCP）已得到发展，以提供具有高空间分辨率的胆道和胰管图像。这些三维数据可用于磁共振虚拟内镜检查（MRVE）中的容积再现，以可视化胆囊、胆管和胰管的管腔。为了在工作站上通过阈值设置观察管腔变化，我们制作了内径分别为2毫米、3毫米和6毫米的原始模型。我们通过比较实际内径，使用几种阈值设置来检查管腔直径的变化，以确定合适的阈值设置，然后将其应用于50例临床病例，包括胰腺肿瘤、肝脏肿瘤和胆道结石。我们获取了胆囊、胆管和胰管的MRVE图像，以评估该方法的临床实用性。在模型研究中，阈值小于20%时可获得与实际管腔直径相同的值。在所有临床病例中，我们使用已确定合适的阈值获取了胆囊、胆管和胰管的MRVE图像，并对每个区域的诊断有用性进行评分。胆道的MRVE图像提供了许多补充信息，包括结石的存在、恶性肿瘤对导管的侵犯以及狭窄后部分的可视化。胆囊的MRVE图像对诊断没有显著改善（P = 0.311），但胆管和胰管的MRVE图像有改善（P < 0.05）。此外，MRVE可能有助于在胆管镜检查期间进行导航。因此，MRVE是一种用于检查胆道和胰腺病变的临床有用技术。
