Abstract

Background and Objective: today, in the world of Cardiovascular Magnetic Resonance Imaging (CMR), another new technique, called Perfusion Weighted MRI, has been introduced that is widely used in the evaluation of the status of cardiac hemorrhage and probable ischemia. Unfortunately, the mentioned technique has only been qualitatively and visually examined in many CMR centers, while its highest potential has been for providing Time-Intensity Curves (TICs) and quantitative measurements. Such curves are also used in dynamic imaging of other parts of the human body including the pituitary gland and breast tissue. In this research, we examined the relationship between the curves obtained from the Perfusion Weighted MRI technique in the detection of myocardial infarction and myocardial ischemia lesions, and then, compared them with the Early and Late Gadolinium Enhancement CMR gold standards. Methodology: 20 patients with a history of coronary artery disease underwent MRI with a Siemens 1.5T machine. All patients had a normal renal function. The imaging process was performed in four stages: left ventricular imaging, perfusion imaging, early gadolinium enhancement imaging, and late gadolinium enhancement imaging. Then, indices of left ventricular function and related curves were evaluated using the CMR42 software. Finally, all curves were analyzed by two cardiothoracic radiologists. Results: 75 vascular territories in the examined 20 patients were studied: 26 territories were detected with clear ischemia, and 49 were detected with a normal coronary status. All curves extracted from those vascular territories were examined and compared regarding simax and time-to-peak indices in normal myocardium and myocardial infarction. The results indicated a significant difference between normal myocardium and cardiac infarct scar tissue in terms of the simax index; however, the difference was not statistically significant in terms of the time-to-peak index. Conclusion: it is a fact that ‘no flow’ zones, which are evaluated in early-contrast images, do not always result in scars in images with late-contrast. But scar tissues, which can be seen in late-contrast images, present themselves in early-contrast images as ‘no flow’ zones. In fact, the present study’s evaluations were mainly done on late-contrast images. Given the significant difference in the simax index between normal myocardium and myocardial infarction, it can be concluded that our interpretation of myocardial infarction was based on highly accurate visual information. Even when there is a doubt about the presence of a vascular territory based on the available visual data, the doubt can be cleared by quantifying the analysis based on the simax index.