On-line flow quantification by low-resolution phase-contrast MR imaging and model-based postprocessing

Over the past decade, magnetic resonance (MR) Imaging has been developed to ward a tool for guiding and evaluating diagnostic and therapeutic intervent ions. Within the field of vascular MR-guided Interventions, MR has potentia l for providing on-line monitoring of the blood volume flow rate, which is relevant during procedures sue as balloon angioplasty and stent placement. We recently reported a hardware and software environment for enabling flow quantification every 8 seconds using nontriggered phase-contrast imaging. I n the present study, the objective was to increase temporal resolution furt her to one evaluation per 4 seconds. We achieve this by lowering spatial re solution to 3 pixels per lumen diameter. The accuracy of the measurements i s preserved by applying model-based postprocessing for quantification of th e volume flow rate. Phantom and volunteer studies are presented, demonstrat ing the accuracy of the model-driven approach for the applied short acquisi tions. The capabilities of the presented approach are Illustrated by the re sults of several hypercapnia experiments and carotid compression tests perf ormed on healthy volunteers. J. Magn. Reson. Imaging 2000;12:623-631. (C) 2 000 Wiley-Liss, Inc.