The diagnostic reliability and validity of noninvasive imaging modalities to assess leptomeningeal collateral flow for ischemic stroke patients

Abstract

Leptomeningeal collateral flow (LMF) is associated with infarct area and clinical outcome for ischemic stroke patients. Although LMF can be detected by multiple imaging methods, but their diagnostic performance is uncertain. The aim of this study was to evaluate the diagnostic validity or reliability of noninvasive image methods in assessing LMF. Databases included PubMed, Web of Science, Embase, and Cochrane Library. Original observational cohort studies. Ischemic stroke patients. Different noninvasive image methods to assess LMF. Newcastle–Ottawa Scale to evaluate the quality of the studies; forest plot to show pooled results; I 2 and Egger test to evaluate the heterogeneity and publication bias. Thirty of the 126 selected studies were eligible. For CT angiography, the interobserver agreement ranged from 0.494 to 0.93 and weighted kappa was 0.888; for patients receiving thrombolysis or endovascular treatment, 0.68 to 0.91; 0.494 to 0.89 for the 2-point system, 0.60 to 0.93 for the 3-point system, 0.68 to 0.87 for the system of >4 points; area under the curve (AUC) was 0.78. For perfusion computed tomography (CTP), the interobserver agreement ranged from 0.724 to 0.872; for patients receiving thrombolysis or endovascular treatment, 0.74 to 0.872; 0.724 for the 2-point system, 0.783 to 0.953 for the 3-point system; the intraobserver agreement was 0.884; AUC was 0.826. For MRI-fluid attenuated inversion recovery (FLAIR), the interobserver agreement ranged from 0.58 to 0.86; for patients receiving thrombolysis or endovascular treatment, 0.75 to 0.86; 0.86 for the two-point system, 0.77 to 0.87 for the system of more than 5 points; AUC was 0.82. No pooled data of CTP and FLAIR. The difference cohort study had difference bias. The unpublished data were not included. CT angiography is a good tool for assessing LMF. CTP shows a good validity and reliability, but its diagnostic value needs more evidence. FLAIR is a good modality to assess LMF. These image methods had better validity and reliability to evaluate LMF of patients receiving thrombolysis or endovascular treatment than all ischemic stroke patients.

Quantitative collateral score for the prediction of clinical outcomes in stroke patients: Better than visual grading

“…The reason for the discrepancy may lie in the nature of evaluation methods, namely quantitative method vs. categorical method. The conventional vCS systems, which are based on traditional or dynamic CTA, depend on manual visual assessment, making them prone to both intra- and inter-observer variations ( McVerry et al, 2012 ; Aktar et al, 2020 ; Cui et al, 2021 ). Several vCS systems have been proposed.…”

“…Several vCS systems have been proposed. The prognostic power of different scoring systems varied in different studies, and was far from satisfactory with AUCs ranging from 0.59 to 0.77 ( Berkhemer et al, 2016 ; Lu et al, 2019 ; Seker et al, 2020 ; Cui et al, 2021 ). No consensus has been reached yet in terms of the evaluation criteria.…”

“…Collateral circulation was most commonly evaluated by manually performed visual grading of computed tomography angiography (CTA) images; these findings are reflected as the visual collateral score (vCS). This method requires experienced neuroradiologists and has frequent intra-observer disagreement (McVerry et al, 2012;Cui et al, 2021). Such inaccurate methods may limit the prognostic efficacy of collateral circulation, and a reliable quantitative collateral score (qCS) method is Abbreviations: MT, mechanical thrombectomy; AIS, acute ischemic stroke; CTA, computed tomography angiography; vCS, visual collateral score; qCS, quantitative collateral score; LDL-C, Low-density lipoprotein cholesterol; mRS, modified Rankin Scale; MCA, middle cerebral artery; ICA, internal carotid artery; CTP, computed tomography perfusion; NCCT, non-contrast computed tomography; NIHSS, National Institute of Health stroke scale; TOAST, trial of ORG 10,172 in acute stroke treatment; mTICI, the modified Treatment In Cerebral Ischemia; ICC, intraclass correlation efficient; ROC, receiver operating characteristic; AUC, area under the curve; OR, odds ratio.…”

“…Collateral circulation was most commonly evaluated by manually performed visual grading of computed tomography angiography (CTA) images; these findings are reflected as the visual collateral score (vCS). This method requires experienced neuroradiologists and has frequent intra-observer disagreement ( McVerry et al, 2012 ; Cui et al, 2021 ). Such inaccurate methods may limit the prognostic efficacy of collateral circulation, and a reliable quantitative collateral score (qCS) method is needed ( Shi et al, 2019 ).…”

MRI for collateral assessment pre-thrombectomy and association with outcome: a systematic review and meta-analysis

“…While previous systematic reviews demonstrate the importance of pre-treatment collateral status (CS) on outcome, only two included magnetic resonance imaging (MRI) methods but neither correlated with outcome [ 4 , 5 ]. Those that did find associations between CS and outcome were computed tomography (CT) and digital subtraction angiography (DSA) based [ 6 , 7 ], and one only included patients treated with thrombolysis [ 8 ].…”