Hyperperfusion on Arterial Spin Labeling MRI Predicts the 90‐Day Functional Outcome After Mechanical Thrombectomy in Ischemic Stroke

Abstract

Background The prognostic significance of hyperperfusion after reperfusion therapy in patients with acute ischemic stroke (AIS) remains controversial. Purpose To investigate the clinical factors associated with hyperperfusion, and the 90‐day prognostic value of hyperperfusion after mechanical thrombectomy in AIS patients. Study Type Retrospective. Population/Subjects Fifty‐four AIS patients who underwent mechanical thrombectomy. Field Strength/Sequence Time‐of‐flight MR angiography, pulsed arterial spin labeling (ASL), diffusion‐weighted imaging (DWI), and susceptibility‐weighted imaging were performed at 3.0T within 1 week after thrombectomy. Assessment Clinical factors including demographics, risk factors, stroke and treatment characteristics were collected and assessed. Hyperperfusion on ASL was defined as a focal increased cerebral blood flow on the affected side ≥130% of its mirror counterpart. Good clinical outcome at 90 days was defined as modified Rankin Scale score of 0–2. Statistical Tests The interrater agreement was assessed using Cohen's kappa or the intraclass correlation coefficient. The relationship between hyperperfusion and clinical factors were analyzed by appropriate univariate statistics. Predictors of 90‐day functional outcome were assessed by univariate analyses followed by multivariate logistic regression analysis and receiver‐operating‐characteristic curves. Results Thirty‐six (66.7%) patients developed hyperperfusion on ASL after thrombectomy. Hyperperfusion was significantly correlated with successful recanalization (P < 0.05) and improvement of National Institutes of Health Stroke Scale scores at 24 hours (NIHSS24h) (P < 0.05). A higher incidence of hemorrhage transformation was observed in patients with hyperperfusion than those without (63.9% vs. 50.0%), but no significant difference was found (P = 0.327). NIHSS24h (odds ratio [OR], 0.75, [95% confidence interval [CI] 0.62–0.91], P < 0.05), lesion volume on diffusion‐weighted imaging (OR, 0.97, [95% CI 0.95–1.00], P < 0.05), and hyperperfusion on ASL (OR, 9.8, [95% CI 1.7–55.3], P < 0.05) were independent variables for predicting good functional outcomes. Data Conclusion Hyperperfusion on ASL correlated with successful recanalization and may be an independent prognostic marker for good neurological outcomes at 90 days in AIS patients after mechanical thrombectomy. Level of Evidence 4 Technical Efficacy Stage 2

Three Dimensional-Arterial Spin Labeling Evaluation of Improved Cerebral Perfusion After Limb Remote Ischemic Preconditioning in a Rat Model of Focal Ischemic Stroke

“…Several studies have investigated the use of 3D-ASL to detect perfusion abnormalities in the context of infarction (Chen et al, 2016;Noguchi et al, 2016). Lu et al (2021) suggested that hyperperfusion on 3D-ASL correlated with successful recanalization and might be an independent prognostic marker for good neurological outcomes in patients with AIS. 3D-ASL can objectively show the development of collateral circulation around the infarcted area and provide an informed assessment of the disease and prognosis (Yuan et al, 2015).…”

Implications of Post-recanalization Perfusion Deficit After Acute Ischemic Stroke: a Scoping Review of Clinical and Preclinical Imaging Studies

“…In a retrospective study of 54 EVT-treated patients, 36 patients showed hyperperfusion in the infarcted area on ASL-based scans at 4 days (median) after stroke onset, which was related to successful recanalization and associated with an improvement in NIHSS at 24 h. Hyperperfusion was, independently from successful recanalization, also associated with good functional outcome at 90 days post-stroke [40]. Potreck et al [41] visually graded hyperperfusion using DSC-MRI at 24 h after successful EVT in a prospective study of 38 patients who achieved complete recanalization (mTICI ≥ 2b).…”

“…Definition Hyperperfusion, which can be described by an increase of CBF of > 100% of baseline [38], sits at the other end of the reperfusion abnormality spectrum. Although formal definitions are lacking, some studies have applied CBF ≥ 130% of control (contralateral) values as hyperperfusion threshold [39,40], whereas other studies relied on qualitative assessment [41,42]. Tmax maps may theoretically be used to delineate areas of hyperperfusion, but threshold values have not been published.…”

“…Multiple clinical studies have reported an association between post-ischemic hyperperfusion and favorable clinical outcome [9,14,25,[39][40][41][43][44][45][46]. Several studies observed hyperperfusion outside of the final infarct [14,25,43,45], which could be suggestive of hyperperfusion being a marker of penumbral salvage.…”

Arterial Spin Labeling technique and clinical applications of the intracranial compartment in stroke and stroke mimics - A case-based review

“…Increased ASL signal post thrombectomy correlates with improved tissue and clinical outcomes. 45,46 ASL can also be helpful in EVT cases in assessing reperfused tissue as characterized by increased ASL signal in the previously hypoperfused tissue (Figure 7). Figure 7 demonstrates acute infarction in right frontal operculum.…”