MR PORTOGRAPHY - PRELIMINARY COMPARISON WITH CT PORTOGRAPHY AND CONVENTIONAL MR-IMAGING

Magnetic resonance (MR) imaging with arterial portography (MRAP) was c ompared with computed tomography with arterial portography (CTAP) and conventional MR imaging for preoperative evaluation of hepatic masses in eight patients (nine studies). Twenty contiguous, 10-mm-thick-secti on CTAP images were obtained. MR imaging included T1- and T2-weighted spin-echo and fast multiplanar SPGR (spoiled gradient-recalled acquisi tion in the steady state) techniques. For MRAP, 0.1 mmol/kg gadopentet ate dimeglumine was injected into the superior mesenteric artery. Port ographic-phase, 8-mm-thick-section, axial SPGR images were first obtai ned, followed by ''systemic phase'' SPGR images. Lesions were seen bes t on the portographic-phase MRAP images and were less conspicuous on t he systemic-phase MRAP, CTAP and conventional MR images. Of 19 visuali zed lesions. 18 were seen with MRAP; however; five subcentimeter lesio ns seen with MRAP were not seen with conventional MR imaging or CTAP. Systemic recirculation of iodinated contrast material from the bolus a nd from previous angiography is a potential limitation of CTAP. For bo th CTAP and MRAP, optimal results are expected if all images are obtai ned during a single breath hold, within seconds of the onset of contra st agent administration.