Introduction: Digital subtraction angiography (DSA) has traditionally been used to provide high-resolution anatomical imaging but is not readily used to assess cerebral hemodynamics. Here we examine the relationship between time density transit time (TT) on DSA, vessel cross-sectional area and flow obtained from QMRA of the same artery.
Methods: Patients seen at our institution between 2009 and 2015 who had concomitant DSA and Quantitative MRA prior to any treatment for a vascular lesion were retrospectively reviewed. Transit time (TT) on DSA was defined as time needed for contrast to change image intensity from 25%-25%. Flow volume rate (mL/min) and vessel cross-sectional area were measured using QMRA. Angio flow index (FI) = [Cross sectional area/TT25-25%]was calculated and analyzed relative to flow.
Results: 48 patients (mean age was 51 years) were included. There was a significant correlation (Spearman’s) between the MCA and ACA flows and the angio flow index (P<0.001, rho=0.66). The same positive correlation was present for the individual MCA flows (P<0.001, rho=0.81) and ACA flows (P<0.001, rho=0.52) and the angio flow index.
Conclusion: Angio flow index correlated significantly with intracranial flows measured by QMRA, and so angio flow index may be used as an indirect tool for assessment of cerebral flow during interventional procedures.