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

Background-Magnetic resonance angiography (MRC) is currently under investig ation for non-invasive biliary tract imaging. Aim-To compare MRC with endoscopic retrograde cholangiography (ERC) for pre treatment 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 o f the hilar obstruction was a cholangiocarcinoma in 15 patients and a hilar compression in five (one hepatocarcinoma, one metastatic breast cancer, on e 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. Tu mour location, extension, and type according to Bismuth's classification we re 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%). Succe ssful 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, a nd in a third a curative resection was attempted. Effective drainage was no t achieved in six patients (30%). If management options had been based only on MRC, treatment choices would have been modified in a more appropriate w ay in 5/18 (28%) patients with satisfactory MRC. Conclusion-MRC should be considered for planning treatment of malignant hil ar strictures. Accurate depiction of high grade strictures for which endosc opic drainage is not the option of choice can preclude unnecessary invasive imaging.