MR cholangiopancreatography (MRCP) at 0.5 T: technique optimisation and preliminary results

Abstract

The aim of our study was to evaluate the feasibility of MR cholangiopancreatography (MRCP) at 0.5 T. To our knowledge no previous studies of MRCP have been performed at mid-field strength. Thirty-one patients with dilated biliary systems were examined with three-dimensional MRCP. All patients were studied with a 0.5 T superconducting magnet. A three-dimensional turbo spin-echo (TSE) sequence was acquired (TR = 5000 ms, 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. Endoscopic 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 patients. Choledocholithiasis was correctly evaluated by MRCP in 12 of 12 patients, compared with 11 correct diagnoses by ERCP. The presence and the level of the stricture were accurately shown in 16 of 16 patients with MRCP and in 13 of 16 patients with ERCP. The peripheral biliary tree above the obstruction and pancreatic duct were better evaluated by MRCP in all cases. In 3 of 3 patients who had undergone bilio-enteric surgery, a correct evaluation of the site of the anastomosis was possible with MRCP. It is concluded that MRCP performed at mid-field strength allows good visualisation of the dilated biliary system. Excellent results have been obtained on comparison with ERCP. MRCP performed at mid-field strength could have the same clinical value as high field strength MRCP.

MR cholangiopancreatography: technique, potential indications, and diagnostic features of benign, postoperative, and malignant conditions

“…Resolution may be further improved by using a surface coil and a smaller FOV [19] or a multicoil array and an image matrix of 512 × 256 pixels [22]. Pavone et al have shown that MRCP images of good quality can also be obtained with the body coil of a 0.5-T system by using a matrix size of 83 × 128 [23]. Acquisition of volumetric (3D) FSE data sets has recently become possible with some equipment [20,23].…”

“…Pavone et al have shown that MRCP images of good quality can also be obtained with the body coil of a 0.5-T system by using a matrix size of 83 × 128 [23]. Acquisition of volumetric (3D) FSE data sets has recently become possible with some equipment [20,23]. In comparison with the multislice (2D) FSE technique, the 3D technique allows not only to obtain high-quality MIP reconstructions in all planes from a single acquisition, but also to reduce the slice thickness to 2 mm or less, if necessary.…”

“…Images of adequate quality may be obtained with many different types of equipment. Most investigators have used 1.0 or 1.5-T units [15][16][17][18][19][20][21][22], but a recent report has shown that good results can also be obtained at 0.5 T [23]. A variety of pulse sequences has been proposed for MRCP; some of the protocols are compared in Table 1.…”

“…Fast-spin-echo (FSE) sequences have been used successfully for MRCP by several investigators including ourselves [18][19][20][21][22][23][24]. Compared with CE-FAST or PSIF sequences, FSE offers better signal-to-noise and contrastto-noise ratios, and a lower susceptibility to artifacts due to motion, intestinal gas, and surgical clips.…”

Clinical Significance of Magnetic Resonance Cholangiopancreatography for the Diagnosis of Cystic Tumor of the Pancreas Compared with Endoscopic Retrograde Cholangiopancreatography and Computed Tomography

“…The high sensitivity ofMRCP for abnormalities of the biliary tree and pancreatic duct system has been reported (11)(12)(13)(14)(15)(16). MRCP provides both high-quality cross-sectional images of extraductal structures and projectional images of the biliary tree and pancreatic duct system without any oral or intravenous contrast materials.…”