Dilated biliary tract: evaluation with MR cholangiography with a T2-weighted contrast-enhanced fast sequence.

Abstract

A heavily T2-weighted gradient-echo sequence was used for magnetic resonance (MR) imaging of the biliary system in five healthy volunteers and 13 patients with obstructive jaundice. Images were obtained in the sagittal and coronal planes during sequential breath-hold intervals and were post-processed by using a maximum-intensity projection algorithm. The extrahepatic and intrahepatic bile ducts were well visualized in 11 patients. The level of obstruction and the grade of dilatation were depicted with MR cholangiography. However, the cause of obstruction could be determined with MR cholangiography in only eight cases. The part of the biliary system below the obstruction could not be visualized with MR cholangiography. In the volunteers, MR cholangiography could demonstrate the anatomy of the biliary tract in only two subjects. Possible causes for this phenomenon are the limited spatial resolution of MR imaging, partial volume effects, or flow within the bile ducts. MR cholangiography may be a useful adjunctive tool for noninvasive evaluation of patients with obstructive jaundice. However, further technical advances are necessary to improve image quality.

The Qualitative Analysis of Single Shot Fast Spin Echo (SSFSE) and Maximum Intensity Projection (MIP) on Magnetic Resonance Cholangiopancreatography

“…The sensitivity and specificity of MRCP are excellent for evaluating the pancreatobiliary system, and it has been performed prior to ERCP for a diagnosis of pancreatobiliary diseases [4]. In addition, it is a non-invasive test, and provides good quality projection and cross section images of the pancreatobiliary system without an oral or intravenous injection of contrast agents, and can evaluate the lesions in areas other than the bile duct.…”

“…This method is a good imaging technique for examining the biliary system because it is not associated with radiation exposure, is non-invasive and has high accuracy [4]. In addition, in a range of pancreatobiliary diseases, the diagnostic utility and accuracy of MRCP have been reported.…”

Estudo comparativo entre a colangiopancreatografia por ressonância magnética e a colangiopancreatografia endoscópica no diagnóstico das obstruções biliopancreáticas

“…Em 1991, WALLNER et al (31) , utilizando o princípio físico do sinal hiperintenso em T2, dos fluidos estacionários, idealizaram a colangiopancreatografia através da ressonância magnética, demonstrando as vias biliares e pancreáticas delineadas pelo líquido em seu interior (bile e suco pancreático). Pisani O presente estudo comparou os resultados finais de diagnósticos obtidos com CPGE e CPRM para pacientes com obstrução no sistema biliopancreático.…”

“…Em 1991, WALLNER et al (31) idealizaram a colangiopancreatografia através da ressonância magnética (CPRM), demonstrando as vias biliares e pancreáticas com imagens de resolução espacial semelhante aos da CPGE. A obtenção delas baseou-se na presença de líquidos (bile e suco pancreático) dentro dos ductos biliares e pancreáticos, que funcionavam como meio de contraste.…”

A colangiopancreatografia por ressonância magnética deve substituir a colangiopancreatografia endoscópica retrógrada no algoritmo diagnóstico das doenças biliopancreáticas?

“…A colangiopancreatografia por ressonância magnética (CPRM) baseia-se no princípio físico do sinal hiperintenso dos fluídos estacionários (bile, derrames cavitários, cistos) em T2, descrito por WALLNER et al (15) , em 1991. Assim, sem a injeção de contraste ou de radiação ionizante, são obtidas imagens-fonte, de cortes axiais, das vias biliares e pancreáticas.…”