In asymptomatic patients with established cardiovascular risk factors, a dysfunction of the coronary circulation, as determined with PET flow measurements, is widely recognized as early functional stage of developing structural CAD ( 1, 5, 6, 13). Previous studies have suggested that a reduction in hyperemic MBFs and myocardial flow reserve (MFR = hyperemic MBF/rest MBF) improves prognostication to standard myocardial perfusion assessment ( 7– 12).
Positron emission tomography/computed tomography (PET/CT)-guided assessment of myocardial perfusion with concurrent quantification of myocardial blood flow (MBF) in milliliters per gram per minute by means of radiotracer kinetic modeling affords a comprehensive identification and delineation of subclinical and clinically manifest coronary atherosclerosis ( 1– 6). The concurrent assessment of myocardial perfusion and several hyperemic flow parameters with PET/CT may indeed open novel avenues of precision medicine to guide coronary revascularization procedures that may potentially lead to a further improvement in cardiovascular outcomes in CAD patients. Conversely, initial results of the assessment of a longitudinal hyperemic flow gradient suggest this novel flow parameter to be specifically related to increases in CAD caused epicardial resistance. The non-specific origin of decreases in hyperemic MBFs and MFR, however, prompts an evaluation and interpretation of regional flow in the appropriate context with the presence of obstructive CAD. The addition of regional hyperemic flow parameters, therefore, may afford a comprehensive identification and characterization of flow-limiting effects of multivessel CAD. The detection of a regional myocardial perfusion defect during vasomotor stress commonly identifies the culprit lesion or most severe epicardial narrowing, whereas adding regional hyperemic MBFs, myocardial flow reserve (MFR), and/or longitudinal flow decrease may also signify less severe but flow-limiting stenosis in multivessel CAD. Positron emission tomography/computed tomography (PET/CT) applied with positron-emitting flow tracers such as 13N-ammonia and 82Rubidium enables the quantification of both myocardial perfusion and myocardial blood flow (MBF) in milliliters per gram per minute for coronary artery disease (CAD) detection and characterization. 2Department of Radiology, School of Medicine, Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States.1Department of Medicine, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States.
0 kommentar(er)
