Evaluating cerebral hemodynamics using quantitative digital subtraction angiography and flat-detector computed tomography perfusion imaging: A comparative study in patients with carotid stenosis

Background: The efficacy of both quantitative digital subtraction angiography (QDSA) and flat-detector computed tomography perfusion (FD-CTP) is equivalent to that of magnetic resonance perfusion (MRP) in assessing perfusion deficits in carotid stenosis. This study evaluated the feasibility of using FD-CTP to monitor cerebral hemodynamics during carotid stenting. Methods: Thirteen patients with extracranial carotid stenosis (>70%) were included. Both QDSA and two FD-CTP sessions were performed before and after carotid stenting. Cerebral circulation time (CCT) was defined as the difference between the time to peak (TTP) of the parietal vein and the cavernous internal carotid artery. For FD-CTP and MRP, regions of interest (ROIs) were placed in the middle cerebral artery territory at the basal ganglia level of both stenotic and contralateral hemispheres for measurement. The TTP ratio (rTTP) was defined as stenotic TTP divided by contralateral TTP; and ratio of cerebral blood volume (rCBV), ratio of mean transit time (rMTT), and ratio of cerebral blood flow (rCBF) were defined similarly. Both CCT and ratio perfusion parameters were compared during stenting. Results: Before stenting, only rCBF (r = 0.73) and rTTP (r = 0.58) demonstrated correlations between FD-CTP and MRP; CCT correlated with only rMTT in MRP (r = 0.69). After stenting, only rCBF (r = 0.56) indicated a correlation between FD-CTP and MRP. Regarding cerebral flow after stenting, CCT (4.61 ± 1.6 s) was shortened, rMTT (1.12 ± 0.04) and rTTP (r = 1.05 ± 0.03) decreased, and rCBF (0.91 ± 0.16) increased significantly. Conclusion: FD-CTP provides a potentially more comprehensive hemodynamic assessment of parenchymal perfusion changes compared with QDSA during carotid stenting, but FC-CTP requires additional 18 min. FD-CTP confirmed that the normalization of cerebral hemodynamics began immediately and continued for 1–3 days.