Postischemic Hyperperfusion on Arterial Spin Labeled Perfusion MRI is Linked to Hemorrhagic Transformation in Stroke

Abstract

The purpose of this study was to investigate the relationship between hyperperfusion and hemorrhagic transformation (HT) in acute ischemic stroke (AIS). Pseudo-continuous arterial spin labeling (ASL) with background suppressed 3D GRASE was performed during routine clinical magnetic resonance imaging (MRI) on AIS patients at various time points. Arterial spin labeling cerebral blood flow (CBF) maps were visually inspected for the presence of hyperperfusion. Hemorrhagic transformation was followed during hospitalization and was graded on gradient recalled echo (GRE) scans into hemorrhagic infarction (HI) and parenchymal hematoma (PH). A total of 361 ASL scans were collected from 221 consecutive patients with middle cerebral artery stroke from May 2010 to September 2013. Hyperperfusion was more frequently detected posttreatment (odds ratio (OR) = 4.8, 95% confidence interval (CI) 2.5 to 8.9, P < 0.001) and with high National Institutes of Health Stroke Scale (NIHSS) scores at admission (P<0.001). There was a significant association between having hyperperfusion at any time point and HT (OR = 3.5, 95% CI 2.0 to 6.3, P < 0.001). There was a positive relationship between the grade of HT and time-hyperperfusion with the Spearman's rank correlation of 0.44 (P = 0.003). Arterial spin labeling hyperperfusion may provide an imaging marker of HT, which may guide the management of AIS patients post tissue-type plasminogen activator (tPA) and/or endovascular treatments. Late hyperperfusion should be given more attention to prevent high-grade HT.

Baseline collateral status and infarct topography in post-ischaemic perilesional hyperperfusion: An arterial spin labelling study

“…Our results are supported by a recent study also showing a strong link between postischaemic hyperperfusion detected by ASL-MRI and HT. 9 Using multivariate logistic regression Yu et al demonstrated that hyperperfusion was an independent risk factor for HT and that hyperperfusion patients were approximately three times as likely to experience HT compared with patients without hyperperfusion. However, the study included patients presenting with hyperperfusion both within (lesional) as well as around (peri-lesional) DWI lesions.…”

Cyclosporine A, a Potential Therapy of Ischemic Reperfusion Injury. A Common History for Heart and Brain

“…Despite the voxel-by-voxel association of increased perfusion with infarction, there were no significant differences in the degree of clinical improvement in patients with regions of hyperemia versus those without. Recently, Yu et al [87] using arterial spin labeling (ASL) showed that late ASL increased perfusion might predict high-grade HT. Larger future MRI studies are necessary to assess the extent to which hyperemia may result in unfavorable clinical outcome in human stroke.…”

Arterial spin-labelled perfusion MRI demonstrates early spontaneous recanalisation of clot after cardiogenic embolism

“…Restoration of flow to ischaemic regions can be seen as focal hyperperfusion on ASL imaging, following both spontaneous recanalisation and thrombolysis 1 2. On the other hand, postischaemic hyperperfusion on ASL imaging positively associated with haemorrhagic transformation in acute ischaemic stroke 3. Therefore, CT follow-up is important to detect haemorrhagic lesion in spontaneous recanalisation, especially if accompanied by signs of hyperperfusion on ASL imaging.…”