Abstract
Background: Quantifying the myocardial blood flow (MBF) using 13N-ammonia or 15O-H2O position emission tomography (PET) is a gold standard method. However, PET MBF measurements can only be applied for limited population. A recent study showed a new myocardial uptake ratio (MUR) method. This approach may apply for the quantitative evaluation of the MBF and functional severity of the CAD. The purpose of the present study was to evaluate the diagnostic utility of the myocardial flow reserve (MFR) with this MUR method using a standard dual-head single-photon emission computed tomography (SPECT) camera.
Methods: A total of 46 known or suspected CAD patients underwent adenosine stress dynamic planar acquisition following conventional 99mTc-sestamibi (99mTc-MIBI) SPECT. The area under the curve of aorta time-activity curve (TAC) was used to obtain the time integral of the first-pass 99mTc-MIBI count. The myocardial counts were obtained from SPECT short-axis images. MUR under stress and rest conditions was estimated and corrected with the cross calibration factor. Then, the MFR was calculated as the ratio of stress MUR to rest MUR.
Results: The median MFR was significantly lower in patients with CAD than that without CAD (1.23 [IQR, 1.10-1.34] vs. 1.33 [IQR, 1.26-1.61], p<0.05).
Conclusions: Patients with CAD showed significantly lower MFR using the dynamic MUR approach. Therefore, the MUR method was useful for distinguish between CAD and non-CAD patients. In this regard, MFR measurements may be useful in discerning CAD from non-CAD for the selected population.
