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

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.