Current Status of Myocardial Blood Flow Quantification by CT and MR

Abstract

I n this issue of the Annals of Nuclear Cardiology, there are two review articles related to myocardial blood flow assessment (MBF; ml/g-myocardium/min). One is using dynamic perfusion CT by Manabe et al., and the other is using dynamic perfusion MR by Ichikawa et al. (1, 2). MBF measurement has been mainly performed by dynamic positron emission tomography (PET) imaging with 13 N-NH3, 15 O-H2O, and 82 Rb (3, 4). PET MBF assessment is a gold standard for non-invasive quantification of MBF, however, there are limited number of facilities where dynamic perfusion PET can be available in the clinical settings. Recently, there are trials to quantify MBF using semi-conductor detector single photon emission computed tomography (SPECT) (5) and the PET MBF quantification methodology using 99m Tc-MIBI, 99m Tctetrofosmin or 201 Tl-TlCl. In addition to the limited number of facilities where semi-conductor or high sensitivity SPECT systems are installed, there are limitations of SPECT MBF quantification such as underestimation and accuracy when using 99m Tc-agents, and low counts or noisy data. If non-invasive MBF assessment is available with widely used modalities such as CT and MR, it would be of beneficial for many coronary artery disease (CAD) patients in the clinical setting.