Dynamic CT-perfusion parameters as indicators of microcirculation: investigation in patients without obstructive coronary artery disease.

Abstract

Aim: To investigate the relationship between each CTP parameter and that between CTP parameters and patient characteristics in patients without obstructive coronary artery disease (CAD).

Materials and methods: Seventy-seven (28 female; 65.0±10.3 years) patients with suspected CAD who underwent coronary CT angiography (CCTA) and dynamic CTP with vasodilator stress were included. Patients with obstructive coronary stenosis (≥50%) on CCTA were excluded. Myocardial blood flow (MBF) and myocardial blood volume (MBV) were calculated using the slope and peak of the time-attenuation curves of the myocardium and blood. Perfused capillary blood volume (PCBV), extravascular extracellular volume (EEV), and flow extraction product (FE) were calculated using the extended Tofts model.

Results: MBF, MBV, and PCBV were strongly correlated with each other (all r > 0.80 and all p < 0.001), whereas FE and EEV were strongly correlated with each other (r = 0.88 and p < 0.001). In univariate linear regression analysis, male sex and smoking status were significantly associated with MBF, MBV, and PCBV, while age was significantly associated with FE and EEV (all p < 0.05). In stepwise multivariate analysis, smoking status was independently associated with MBF, MBV. and PCBV, while age was the only factor associated with FE and EEV (all p < 0.05).

Conclusion: FE and EEV may reflect different mechanisms of microvascular dysfunction than MBF, MBV, and PCBV.