DETECTION AND LOCALIZATION OF ACUTE MYOCARDIAL-INFARCTION - COMPARISON OF GADOLINIUM DIETHYLENETRIAMINE PENTAACETIC ACID ENHANCED MAGNETIC-RESONANCE-IMAGING AND TC-99M-PYROPHOSPHATE-SINGLE PHOTON-EMISSION TOMOGRAPHY IMAGING

The ability of gadolinium diethylenetriamine pentaacetic acid enhanced cardiac magnetic resonance imaging (Gd-MRI) to detect and localize th e area of an acute myocardial infarction (AMI) was compared to technet ium-99-m-pyrophosphate-single photon emission tomography (Tc-PYP-SPECT ) imaging. 18 patients with ECG and/or angiographically proven AMI wer e examined. 11 patients had Q wave and 7 had non-Q wave infarctions by ECG. Gd-MRI was found to be more sensitive for the detection of AMI t han Tc-PYP-SPECT (100 and 44%, respectively, p < 0.01). This differenc e in sensitivity seemed to be more prominent in the non-Q wave infarct ion subgroup, although the difference was not found to be statisticall y significant (100 and 29% rspectively, p > 0.05), possibly due to the small sample size in the subgroup. The ability of Gd-MRI to localize the infarction correlated well with ECG, coronary angiography and echo cardiography findings, and was found to be superior to Tc-PYP-SPECT im aging (percentage of correct localization being 94 and 39%, respective ly, p < 0.01). A limitation of the Gd-MRI technique was the inability for reasons of patient stability, claustrophobia or logistics to image 18% of potential patients in the MRI facility. Gd-MRI is a highly sen sitive technique for the detection and localization of AMI. It appears to be superior to Tc-PYP-SPECT imaging. With the use of different pul se sequences (e.g., cine-MRI techniques), MRI can gather additional in formation regarding myocardial function and in the future may replace many discrete myocardial imaging techniques including radionuclide exa minations.