COMPARISON OF DYSPROSIUM DTPA BMA AND SUPERPARAMAGNETIC IRON-OXIDE PARTICLES AS SUSCEPTIBILITY CONTRAST AGENTS FOR PERFUSION IMAGING OF REGIONAL CEREBRAL-ISCHEMIA IN THE RAT

The aim of the study was to compare the first-passage profiles of dysp rosium diethylenetriamine penta-acetic acid bis(methylamide) (DTPA BMA ) and the superparamagnetic iron oxide particles NSR 0430 in regions w ith severe and moderate cerebral ischemia, In seven rats subjected to middle cerebral artery occlusion, two dynamic MR perfusion imaging ser ies were acquired after intravenous bolus injections of .5 mmol/kg dys prosium DTPA BMA and .06 mmolFe/kg iron oxide particles, respectively, The doses were chosen to obtain similar maximum signal change in norm ally perfused brain. The first-passage profiles were compared in a reg ion of interest (ROI) in the core area with severe ischemia and in a R OI in the penumbra area of moderate ischemia. The results were compare d both as the calculated mean signal intensity versus time curves for all seven rats and statistically for an estimated mean transit time (M TT) after gamma variate fitting of the calculated concentration versus time curves. The first-passage profiles for the two contrast agents w ere similar, both in the core area of severe ischemia and in the penum bra area of moderate ischemia. In this rat stroke model, dysprosium DT PA BMA and the superparamagnetic iron oxide particles NSR 0430 were fo und to be equally efficacious for the diagnosis of the perfusion defic it, but if safe for human investigations, iron oxide particles would h ave an advantage as equal susceptibility effect may be achieved with s maller injection volumes.