ABSTRACT
Objective:To assess the value of amide proton transfer weighted (APTw) imaging in the evaluation of pH changes in infarct core (IC) and ischemic penumbra (IP) in subacute cerebral infarction.Methods:The data of twenty-three subacute cerebral infarction patients with unilateral steno-occlusive disease of the middle cerebral artery (subacute infarction group) from April to November 2019 in the First Affiliated Hospital of Dalian Medical University were prospectively analyzed. Fifteen healthy volunteers were enrolled in this study as the control group. All subjects underwent conventional MRI, DWI, 3D-pseudo continuous arterial spin labeling (3D-pCASL) and APTw sequences. Based on DWI images, relative cerebral blood flow (rCBF) and APTw images to determine the region of IC, blood flow penumbra [cerebral blood flow(CBF)-DWI mismatch area, IP CBF] and metabolic penumbra (APTw-DWI mismatched area, IP APT). 3D ROIs were used to semi-automatically measure the APTw signals and the volume of IC and IP CBF of the patients in subacute infarction group. The comparison of APTw signals between the infarct side and the contralateral side in the subacute infarction group, the comparison of bilateral APTw signals in the control group, and the comparison of APTw signals in the IC and IP CBF regions were performed by paired-sample t test or Wilcoxon signed-rank test. The paired-sample t test or Mann-Whitney U test was used to compare the APTw signals between the two groups. The Friedman test was applied to compare the difference of volumes among IP CBF1.5, IP CBF2.5 and IP APT . Results:There was no significant difference of the APTw signals among the IC, the contralateral side in the subacute infarction group and the control group ( P>0.05). The APTw signals of IP CBF and IC of the infarction group were statistically different ( P<0.05). Compared with the contralateral side of IP CBF1.5 (3.7±1.7, -1.84±1.48, 5.57±2.75), the APTwmax (3.07±1.41, t=-3.012, P=0.006), APTw min [-1.30 (-1.74, -0.57), Z=-2.099, P=0.036], and APTwmax-min(4.51±2.58, t=-3.273, P=0.003) signals in the IP CBF1.5 were decreased ( P<0.05). Compared with the contralateral side of IP CBF2.5 [-1.53 (-2.80, -0.91), 5.31±2.61], the APTw min [-1.08 (-1.60, -0.49), Z=-2.616, P=0.009] and APTwmax-min (4.41±2.72, t=-3.228, P=0.004) signals in the IP CBF2.5 were decreased. The volumes of IP CBF1.5 [107.51(50.08, 138.61)mm 3], IP APT [99.00 (53.27, 121.335) mm 3] and IP CBF2.5 [89.91 (51.53, 139.87) mm 3] were successively reduced (χ2=7.913, P=0.019), and the volume of IP CBF2.5 was significantly smaller than that of IP CBF1.5 ( P=0.037). Conclusion:The acid-base metabolism in the IC of subacute cerebral infarction is not obvious, but the blood flow penumbra has local acid-base metabolism imbalance, and the range of metabolic penumbra coincides with the blood flow penumbra.
ABSTRACT
Objective: To investigate the consistency between FLAIR vascular hyperintensity (FVH) and arterial transit artifact (ATA) on three-dimensional arterial spin labeling (3D-ASL) imaging in patients with unilateral middle cerebral artery (MCA) stenosis or occlusion. Methods: Forty-two patients with MCA stenosis or occlusion underwent multimodal MR scanning included T2 FLAIR and 3D-ASL imaging. The incidence of FVH on T2 FLAIR and ATA on 3D-ASL in post labeling delay (PLD)=1.5 s and PLD=2.5 s was counted, and the differences of FVH and ATA were compared. The correlation of FVH, ATA with degree of vascular stenosis and clinical data were analyzed. Results: There was no statistical difference of incidence between FVH and ATA in patients with unilateral MCA stenosis or occlusion when PLD=1.5 s and PLD= 2.5 s, respectively (χ2=3.96, 3.80, P=0.77, 0.30). The incidence of FVH (r=0.30, P<0.05) and ATA (PLD=1.5 s: r=0.35, P<0.05; PLD=2.5 s: r=0.41, P<0.05) positively correlated with the degree of vascular stenosis. Binary Logistic regression analysis showed that age, systolic blood pressure and high density lipoprotein had negative impact on FVH and ATA. Conclusion: FVH has consistency with ATA in patients with unilateral MCA stenosis or occlusion, both of them can be used as indicators to observe collateral circulation.