MR CHOLANGIOPANCREATOGRAPHY (MRCP) AT 0.5 T - TECHNIQUE OPTIMIZATION AND PRELIMINARY-RESULTS

The aim of our study was to evaluate the feasibility of MR cholangiopa ncreatography (MRCP) at 0.5 T. To our knowledge no previous studies of MRCP have been performed at mid-field strength. Thirty-one patients w ith dilated biliary systems were examined with three-dimensional MRCP. All patients were studies with a 0.5 T superconducting magnet. A thre e-dimensional turbo spin-echo (TSE) sequence was acquired (TR = 5000 m s, TE = 244 ms, echo train length = 45; acquisition time = 14 min 10 s ). Coronal images were post-processed with the MIP algorithm. Recently , the parameters have been optimised (TR = 3000 ms, TE = 700 ms, echo train length = 128), reducing the acquisition time to 3 min. Endoscopi c retrograde cholangiopancreatography (ERCP) was performed in 26 cases ; 5 patients underwent percutaneous transhepatic cholangiography PTC. MRCP and ERCP images were evaluated by an experienced radiologist and an endoscopist. MRCP of diagnostic quality was acquired in all patient s. Choledocholithiasis was correctly evaluated by MRCP in 12 of 12 pat ients, compared with 11 correct diagnoses by ERCP. The presence and th e level of the stricture were accurately shown in 16 of 16 patients wi th MRCP and in 13 of 16 patients with ERCP. The peripheral biliary tre e above the obstruction and pancreatic duct were better evaluated by M RCP in all cases. In 3 of 3 patients who had undergone bilio-enteric s urgery, a correct evaluation of the site of the anastomosis was possib le with MRCP. It is concluded that MRCP performed at mid-field strengt h allows good visualisation of the dilated biliary system. Excellent r esults have been obtained on comparison with ERCP. MRCP performed at m id-field strength could have the same clinical value as high field str ength MRCP.