Myocardial infarct sizing and assessment of reperfusion by magnetic resonance imaging: a review

Abstract

Early thrombolytic therapy restores patency of thrombotic coronary artery occlusion in many patients. Intravenous streptokinase appears to be effective in achieving recanalization of the occluded infarct-related artery, thereby reducing myocardial infarct size. However, it may be difficult to assess non-invasively the relative value of different reperfusion therapies. MR imaging with or without the use of contrast agents may become a reliable non-invasive technique to assess infarct size after reperfusion therapy. There are indications that early MR imaging after administration of Gd-DTPA is able to differentiate reperfused from non-reperfused infarcts. Furthermore, MR infarct sizing using Gd-DTPA can demonstrate infarct size reduction in patients with successful reperfusion. The availability of ultrafast imaging methods and MR contrast agents may allow assessment of myocardial perfusion in the near future. This article reviews the current status of MR imaging for evaluating ischemic myocardial disease.

Noninvasive Measurements of Infarct Size After Thrombolysis With a Necrosis-Avid MRI Contrast Agent

“…1 Cardiac MRI emerged as an alternative method for the evaluation of myocardial infarction (MI). 2,3 Although T2-weighted (T2w) spin-echo sequences are able to detect the presence of necrosis, the areas of increased signal intensity (SI) are probably more related to the presence of myocardial edema, systematically overestimating infarct size. 4,5 Therefore, contrast enhancement is needed for optimal contrast between viable and necrotic tissue.…”

“…4,5 Therefore, contrast enhancement is needed for optimal contrast between viable and necrotic tissue. 6,7 Gd-DTPA has been used for infarct-size quantification, 2,8,9 but the enhancement with this contrast agent is nonspecific, and therefore, infarctsize measurements may be less accurate.…”

Aortic stiffness in type-1 diabetes mellitus; beware of hypertension

“…Over the past years considerable progress has been made in the field of cardiovascular magnetic resonance (CMR), providing accurate evaluation of left ventricular mass, volumes and function [1–9]. CMR has shown unique abilities in characterizing myocardial tissue composition.…”

Gated myocardial SPECT imaging; true additional value in AMI?

“…Analysis by gated SPECT imaging may detect these high risk patients who might otherwise be seen as low risk patients due to normal perfusion. This is particularly important in patients with inferolateral ischemia as perfusion artifacts are common in the inferolateral myocardial region [16–31]. Concentration and proximity of subdiaphragmatic radioactivity relative to myocardium comprise a major factor in the nature and severity of inferior wall artifacts.…”