Performance characteristics of magnetic resonance cholangiography in the staging of malignant hilar strictures

Abstract

Background - Magnetic resonance cholangiography (MRC) is currently under investigation for non-invasive biliary tract imaging. Aim - To compare MRC with endoscopic retrograde cholangiography (ERC) for pretreatment evaluation of malignant hilar obstruction. Methods - Twenty patients (11 men, nine women; median age 74 years) referred for endoscopic palliation of a hilar obstruction were included. The cause of the hilar obstruction was a cholangiocarcinoma in 15 patients and a hilar compression in five (one hepatocarcinoma, one metastatic breast cancer, one metastatic leiomyoblastoma, two metastatic colon cancers). MRC (T2 turbo spin echo sequences; Siemens Magnetomvision 1.5 T) was performed within 12 hours before ERC, which is considered to be the ideal imaging technique. Tumour location, extension, and type according to Bismuth's classification were determined by the radiologist and endoscopist. Results - MRC was of diagnostic quality in all but two patients (90%). At ERC, four patients (20%) had type I, seven (35%) had type II, seven (35%) had type III, and two (10%) had type IV strictures. MRC correctly classified 14/18 (78%) patients and underestimated tumour extension in four (22%). Successful endoscopic biliary drainage was achieved in 11/17 attempted stentings (65%), one of which was a combined procedure (endoscopic + percutaneous). One patient had a percutaneous external drain, one had a surgical bypass, and in a third a curative resection was attempted. Effective drainage was not achieved in six patients (30%). If management options had been based only on MRC, treatment choices would have been modified in a more appropriate way in 5/18 (28%) patients with satisfactory MRC. Conclusion - MRC should be considered for planning treatment of malignant hilar strictures. Accurate depiction of high grade strictures for which endoscopic drainage is not the option of choice can preclude unnecessary invasive imaging.