Whole-Heart Dipyridamole Stress First-Pass Myocardial Perfusion MRI for the Detection of Coronary Artery Disease

Abstract

SUMMARYA whole-heart coverage MRI sequence, which employes a hybrid of fast gradient echo and echo planar acquisition imaging (FastCard EchoTrain), has recently been developed. Using this sequence, a first-pass myocardial perfusion MRI was shown to be a good noninvasive modality for detecting coronary artery disease (CAD) in a clinical setting. In addition, the clinical usefulness of delayed enhanced MRI has recently been reported. The objectives of this study were (1) to investigate the accuracy of dipyridamole stress firstpass myocardial perfusion MRI for diagnosing CAD (> 50% stenosis) and (2) to clarify whether additional delayed enhancement MRI has any clinical significance. We performed first-pass myocardial perfusion MRI in 102 consecutive patients (66 ± 9 years old) suspected to have CAD or new lesions in patients with well-documented prior myocardial infarction (MI). Using a 1.5 T cardiac MR imager (GE CV/i), eight short axis MR images of the left ventricle were acquired by injecting gadolinium (0.1 mmol/kg) under dipyridamole infusion stress (0.56 mg/kg). Fifteen minutes later, aminophylline (250 mg) was injected and first-pass perfusion MRI was repeated in the resting state in order to evaluate both the presence of perfusion defect and delayed enhancement. The presence of perfusion defect and delayed enhancement was determined based on a visual qualitative analysis by the agreement of two separate readers who were blinded to any clinical information. Based on the stress and rest findings, no defect, reversible defect, or fixed defect with or without delayed enhancement was recorded in any patient. The MR findings revealed 76 CAD patients, including 24 MI patients with new lesions and 26 patients without CAD on coronary angiography. The presence of stress perfusion defect had a 93% sensitivity and an 85% specificity for diagnosing CAD. A fixed defect showed an 86% sensitivity and a 66% specificity for diagnosing a prior MI. Patients with a fixed defect with delayed enhancement had more significant stenosis in the infarct related artery than in those without any enhancement (11/26 vs 15/20, P < 0.05).

Validation of Magnetic Resonance Myocardial Perfusion Imaging With Fractional Flow Reserve for the Detection of Significant Coronary Heart Disease

“…Our results were also excellent compared with prior studies using MRMPI and suggest that the value of MRMPI may have been underestimated. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Two previous studies have compared MRMPI with FFR. In the first study, however, patient numbers were small (nϭ43), and FFR was measured in only 33% of arteries.…”

“…A number of studies have compared it with more established techniques such as single-photon emission computerized tomography (SPECT), [1][2][3] positron emission tomography, 4,5 and invasive coronary angiography (CA). 1,[3][4][5][6][7][8][9][10][11][12][13][14][15] It has a number of advantages over the other noninvasive techniques, including high spatial and temporal resolution, no exposure to ionizing radiation, no attenuation or scatter artifacts, and no image orientation constraints. Conventional exercise testing has a sensitivity of 67% and specificity of 72% for correctly identifying patients with significant coronary heart disease (CHD) who have not had a previous myocardial infarction.…”

Contrast-Enhanced Magnetic Resonance and Thallium Scintigraphy in the Detection of Myocardial Viability A Prospective Comparative Study

“…Vol 47 No 4 inferolateral wall (kappa, 0.169). The discordant results might be attributed to both imaging artifacts and principal differences in the definition of myocardial viability between the 2 methods studied.…”

“…Patients whose EF improves after revascularization might have a better prognosis in comparison with those in whom it does not, 25) but there are no data available suggesting that the improvement in prognosis after revasculariza-Vol 47 No 4 tion is determined solely by an increase in EF. Samady, et al 26) reported that the lack of improvement in global systolic function after revascularization was not related to an unfavorable long-term prognosis.…”

“…The administration of a gadolinium-based contrast agent enables direct visualization of myocardial perfusion. 4) Delayed scans display the extent of irreversible injury as the contrast agent increasingly accumulates in the areas of acute necrosis and subsequent scar tissue. 5) Contrastenhanced magnetic resonance imaging (CE-MRI) thus has become a novel technique in the assessment of myocardial viability.…”