MR Perfusion-weighted Imaging with CO2 Inhalation Stress Test in Assessment of Cerebrovascular Reserve in Severe Middle Cerebral Artery Stenosis or Occlusion / 中国医学影像学杂志

ABSTRACT

PurposeAlteration of the regional cerebral flow and cerebrovascular reserve (CVR) caused by cerebral artery stenosis or occlusion is an essential risk factor for ischemic stroke. This study aims to assess the CVR in patients with severe middle cerebral artery (MCA) stenosis or occlusion by using MR perfusion-weighted imaging (PWI) with CO2 inhalation stress test. Materials and MethodsPWI were performed before and after CO2 inhalation stress on 28 patients with severe middle cerebral artery stenosis or occlusion and 10 healthy volunteers. The regions of interest (ROI) were put on the affected hemisphere of the MCA blood supply area and the contralateral side in both groups. The relative cerebral blood volume (rCBV), relative mean transit time (rMTT), relative cerebral blood flow (rCBF) and CVR were measured.Results① The rCBV, rCBF and rMTT of the affected side were 149.16±33.01, 18.04±5.24, 8.65±1.81 before CO2 inhalation stress, and 156.23±21.60, 23.77±8.77, 8.72±3.01 after CO2 inhalation stress. The rCBV, rCBF and rMTT were signiifcantly increased (t=1.238, 2.561 and 2.647, P<0.05) after CO2 inhalation stress. The rCBV, rCBF and rMTT of the contralateral side were 176.22±40.12, 22.43±5.74, 8.10±3.71 before CO2 inhalation stress, and 198.54±39.87, 27.64±7.22, 8.03±2.97 after CO2 inhalation. The rCBV, rCBF was significantly increased (t=1.780 and 1.665,P<0.05) while rMTT was signiifcantly decreased (t=2.871,P<0.05) after CO2 inhalation.②The CVR of the affected side, contralateral side and control group were 18.9%, 26.8%, and 39.1%, respectively. There were significantly differences (t=1.604, 2.321 and 1.874,P<0.05) between the affected and contralateral side, the affected side and control group, the contralateral side and control group.ConclusionPWI with CO2 inhalation stress test is valuable in assessing the cerebrovascular reserve in patients with severe middle cerebral artery stenosis or occlusion.