Introduction: The use of digital subtraction angiography (DSA) for semi-quantitative cerebral blood flow (CBF) assessment is a new method. In this report we sought to correlate angiographic transit times (TT) in patients with aneurysmal subarachnoid hemorrhage (aSAH) in relation to Hunt &Hess (H&H) grade.
Methods: A cohort of 28 patients with aSAH were included. Demographic variables, neurological status, and comorbidities were collected. We developed a method to measure CBF by color-coding reconstruction from DSA contrast intensity. Regions of interest were chosen over major cerebral vessels (see legend Figure 1). The estimated TT included Time-To-Peak (TTP) from 0-100% intensity (TTP0-100,), TTP from 25-100% (TTP25-100), and TT from 100-10% (TT100-10). Student t-test was used to compare TT between group 1 (H&H 1-2) and 2 (H&H 3-5).
Results: There was no difference in demographic factors between groups 1(n=10) and 2(n=18). The majority of patients in-group 2 (all except 3) had an external ventricular catheter with normal intracranial-pressure documented during DSA. There was a strong correlation in all TT between M1, M2, A1 and A2 . There was a statistically significant difference in M1-TTP0-100, between groups 1 and 2 (1.98 vs. 2.43 sec, p=0.005), M1-TTP25-100, (1.78 vs 2.7sec, p=0.003) and in M1-TT100-10 (4.68 vs.6.27sec, p=0.012) respectively. Similar difference were observed in A1; A1-TTP0-100(1.84 vs.2.18sec, p=0.001), A1-TTP25-100, (1.63 vs.2.27sec, p=0.001) and in A1-TT100-10 (4.24 vs.5.12sec, p=0.0015, and for the M2 region; M2-TTP0-100, (2.03 vs.2.64sec, p=0.001), M2-TTP25-100, (1.83 vs.2.8sec, p=0.001) and in M2-TT100-10 (4.68 vs.6.2sec, p=0.012). (Figures 2 and 3)
Conclusions: The DSA TT showed significant correlation with H&H grade. TT delays appear to be independent of increased intracranial pressure and may be an indicator of decreased cerebral perfusion in patients with higher H&H grade. The method may serve as an indirect technique for cerebral blood flow assessment in the angiography suite.
Patient Care: The use of computational DSA analysis in angiography suite may supplement routine DSA interpretation and give additional information on cerebral blood flow status
Learning Objectives: By the conclusion of this session, participants should be able to describe the most common cerebral blood flow changes in patients with aSAH, identify the paucity of methods to assess CBF in angiography suite and to discuss a new method based on computational DSA analysis.