MR tomography studies of myocardial function and perfusion after myocardial infarct

Abstract

With the advent of fast pulse sequences, MR imaging of myocardial function and perfusion in ischaemic heart disease has become possible. Prior studies examined either myocardial perfusion or systolic wall motion. We intended to establish an examination procedure to simultaneously investigate regional myocardial motility and perfusion in patients 7-14 days after myocardial infarction. A Turbo-FLASH 2D sequence was optimised to maximise image contrast between normal and malperfused myocardium after Gd-injection using a calculation model basing on the Bloch equation. Calculated values for trigger delay TD, inversion time TI and flip angle alpha were confirmed in a Gd-phantom and healthy volunteers. Subsequently, myocardial motility was studied (cine FLASH 2D sequence) and in slice positions with reduced wall thickening first pass and post contrast studies after 2-10 minutes were performed using the optimised Turbo-FLASH sequence. First pass SI-differences of normal compared to malperfused myocardium vary in relation to TD, TI and alpha in a relevant degree. Reduced myocardial motility was found with a sensitivity of 81% and specificity of 96%. Pathological perfusion patterns were detectable in all of these patients. A combined examination of motility and perfusion is possible by means of MRI and information about the status of postinfarct myocardium can be obtained.