Quantitative Assessment of Regional Myocardial Blood Flow with Clinical SPECT

This article gives an overview of essential requirements and limitations in the quantitative assessment of regional myocardial perfusion or regional myocardial blood flow (rMBF) using existing clinical SPECT systems in clinical settings. One major requirement is the need for acquiring complete projection data without truncation. Attenuation and scatter are then prerequisites to reproduce quantitative images which should represent regional distribution of true radioactivity concentration in the myocardium. A compartmental model could then be applied to extract physiological myocardial perfusion from series of tomographic images acquired following i.v. radio ligand administration. There are also requirements in the radio-ligands if one wish to estimate quantitative blood flow for a physiologicaly wide range of flow. The most important factor is need for a high first-pass extraction fraction. Several factors that affect quantitative ability are reviewed and their importance is illustrated by example.