Analysis of MR Myocardial Perfusion Imaging Using a "Radial" Algorithm

Abstract

Purpose: The goal of this study was to evaluate a radial analysis of dynamically enhanced turbo-fast low-angle shot (TurboFLASH) MR imaging during Gd-DTPA bolus intravenous administration in detecting myocardial ischemia with and without Dipyridamole (DP) stress. Methods: 10 subjects presenting with symptoms suggestive of myocardial ischemia were examined at rest and under DP stress. Rest images were acquired using electrocardiogram (ECG) gated MR (Turbo-FLASH :TE=6,TR=12,Flip=12°,TI=100) 10 to 45 and up to 90 seconds after bolus injection of Gd-DTPA (0.04 mmol/kg) using a Siemens 1.0T Magnetom SP. Stress was induced within the MRI scanner (0.56 mg/Kg DP over 4 minutes) followed by stress MRI after a second bolus of Gd-DTPA in the same position and identical time intervals. Comparison was made with simultaneously obtained rest and stress SPECT imaging after administration of 7-10mCi (259-370 MBq) and an additional 10-30 mCi (370-1110 MBq) of Tc99m-sestamibi respectively. Results: Analysis of the subtraction images and the integrated stress and rest images combined yielded sensitivity and specificity of 90% (95%CI:80-99%) and 91% (95%CI:82-99%) respectively in detecting myocardial ischemic zones compared to SPECT. McNemar analysis determined that subtraction MRI is comparable to SPECT analysis. Conclusion: Turbo-FLASH can provide adequate time and spatial resolution in cardiac perfusion MRI with detectable changes during DP stress. These changes in perfusion are comparable to SPECT when time-signal curves are analyzed using an objective radial technique.