Measurement of blood flow in myocardial layers: A step toward comprehensive physiological evaluation
- PDF / 335,416 Bytes
- 4 Pages / 593.972 x 792 pts Page_size
- 65 Downloads / 165 Views
Department of Internal Medicine, All India Institute of Medical Sciences, New Delhi, India Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL Section of Cardiology, Birmingham Veterans Affair Medical Center, Birmingham, AL Division of Molecular Imaging and Therapeutics, Department of Radiology, University of Alabama at Birmingham, Birmingham, AL
Received Nov 12, 2018; accepted Nov 13, 2018 doi:10.1007/s12350-018-01533-7
See related article, https://doi.org/10.10 07/s12350-018-1445-y. Widely used single-photon emission computed tomography-myocardial perfusion imaging (SPECTMPI) lacks spatial resolution to identify myocardial layers as well as the ability to measure absolute myocardial blood flow (MBF).1 The pitfalls of relative MPI using SPECT are well known in terms of underestimating the extent of coronary artery disease (CAD).2,3 These shortcomings have been overcome by cardiac positron emission tomography (PET) which quantifies absolute global MBF. Quantification of absolute MBF at stress and rest, and the derivation of myocardial flow reserve (MFR) is more desirable than relative flow assessment due to its diagnostic utility, powerful prognostic nature, improved accuracy, reproducibility, and simplified post-processing.1,4–8 Recent consensus statement from the American Society of Nuclear Cardiology and the Society of Nuclear Medicine and Molecular Imaging Cardiovascular Council indicates that these measures are at the cusp of translation into clinical practice.7 While it is well known that there is a transmural variation in MBF in CAD, wherein the subendocardium (SEN) is more vulnerable to
Reprint requests: Navkaranbir S. Bajaj, MD, MPH, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL; [email protected] J Nucl Cardiol 1071-3581/$34.00 Copyright Ó 2018 American Society of Nuclear Cardiology.
ischemia than the subepicardium (SEP)9,10, the majority of cardiac PET literature has focused on measurement of average blood flow across the entire myocardial thickness rather than in layers. This is likely due to the complexities involved in making those measurements. However, if performed accurately, these measurements will reflect the true heterogeneous nature of ischemia and may have incremental diagnostic and prognostic value. Over the past several decades, various techniques have been used to evaluate MBF in layers. The earliest studies, using radionuclide-labeled microspheres to measure regional MBF in animals, suggested a preferential increase in the blood flow to the SEP layer relative to the SEN layer in case of stenosis.9–11 Several studies utilizing different modalities including cardiac PET, magnetic resonance (MR), and computed tomography (CT) perfusion have demonstrated transmural variation in MBF in patients with CAD (Table 1).12–14 While it has been shown in these studies that it may be feasible to make these measurements using different modalities, the diagnostic utility of these measurements has not been well established. Curr
Data Loading...
