Evaluation of myocardial perfusion using Gd-DTPA enhanced fast MR imaging. Special emphasis on acute myocardial infarction and total occlusion or recanalization of the culprit coronary arteries

Using Gd-DTPA enhanced early images obtained with fast MRI, we attempted to evaluate myocardial perfusion in 32 patients with acute myocardial infarction and either total occlusion or recanalization of the culprit coronary artery or arteries. Segmented fast FE images were acquired with electrocardiographic gating and breath holding, including a first-pass image immediately following bolus injection of Gd-DTPA (0.2 ml/kg), and images at 60 sec and 90 sec after injection. In the images thus obtained, regions with no enhancement relative to normal regions were defined as regions of perfusion defect. We investigated the correlation between regions of perfusion defect and coronary arteriographic (CAG) findings and hyper-enhanced regions (infarct zones) at equilibrium. In 78% of patients (25/32), perfusion defect was detected in the first-pass image, and of these patients, 44% (11/25) showed perfusion defect of TIMI grade O to 2 by CAG. In 7 patients with no perfusion defect, CAG showed normal coronary flow (TIMI 3) in the arteries in question. In patients with total occlusion (TIMI 0, Rentrop 2), the region of perfusion defect was larger than the infarct zone at equilibrium and the slope of enhanced intensity was steeper than that in patients with recanalization (TIMI 2-3). In patients with recanalization (n=23), the area of perfusion defect was located within and was smaller than the infarct zone. Based on these findings, we believe that Gd-DTPA fast MRI may be of value in the assessment of myocardial perfusion. (author)