Infarction Distribution Pattern in Acute Stroke May Predict the Extent of Leptomeningeal Collaterals

Abstract

ObjectiveThe aim of this study was to evaluate whether the distribution pattern of early ischemic changes in the initial MRI allows a practical method for estimating leptomeningeal collateralization in acute ischemic stroke (AIS).MethodsSeventy-four patients with AIS underwent MRI followed by conventional angiogram and mechanical thrombectomy. Diffusion restriction in Diffusion weighted imaging (DWI) and correlated T2-hyperintensity of the infarct were retrospectively analyzed and subdivided in accordance with Alberta Stroke Program Early CT score (ASPECTS). Patients were angiographically graded in collateralization groups according to the method of Higashida, and dichotomized in 2 groups: 29 subjects with collateralization grade 3 or 4 (well-collateralized group) and 45 subjects with grade 1 or 2 (poorly-collateralized group). Individual ASPECTS areas were compared among the groups.ResultsMeans for overall DWI-ASPECTS were 6.34 vs. 4.51 (well vs. poorly collateralized groups respectively), and for T2-ASPECTS 9.34 vs 8.96. A significant difference between groups was found for DWI-ASPECTS (p<0.001), but not for T2-ASPECTS (p = 0.088). Regarding the individual areas, only insula, M1-M4 and M6 showed significantly fewer infarctions in the well-collateralized group (p-values <0.001 to 0.015). 89% of patients in the well-collateralized group showed 0–2 infarctions in these six areas (44.8% with 0 infarctions), while 59.9% patients of the poor-collateralized group showed 3–6 infarctions.ConclusionPatients with poor leptomeningeal collateralization show more infarcts on the initial MRI, particularly in the ASPECTS areas M1 to M4, M6 and insula. Therefore DWI abnormalities in these areas may be a surrogate marker for poor leptomeningeal collaterals and may be useful for estimation of the collateral status in routine clinical evaluation.

Leptomeningeal anastomosis and early ischemic lesions on diffusion‐weighted imaging in male murine focal cerebral ischemia

“…Thus, collateral circulation has been evaluated in human stroke using conventional, CT and MR angiograms. Early ischemic lesions are routinely evaluated on MRI-DWI in stroke medicine, and the size of the ischemic lesion has been shown to be associated with the degree of collateral circulation (Aoki et al, 2014;Campbell et al, 2013;Gawlitza et al, 2017;Kim et al, 2014;Lee et al, 2015;Verma et al, 2015), such that poor collateral circulation is closely related to the expansion of early ischemic lesions on MRI-DWI. In the experimental models, MRI has been used to evaluate lesion size and edema volume (Gupta, Sharma, Jagannathan, & Gupta, 2017;He et al, 2017;Huang et al, 2013;Okubo et al, 2007;Woo et al, 2017;Xu et al, 2015;Zhao et al, 2016) as in human stroke, and the beneficial effect of hypothermia on early ischemic lesions has been demonstrated in an MRI-DWI experiment (Wang et al, 2017).…”

Intracranial collateral circulation and its role in neurovascular pathology

“…The relationship between the grades of collateral circulation and the predictability of infarct evolution was a main study focus in recent years [5]. The hemodynamic effects of intracranial collateral circulation may be important to maintain perfusion in the affected regions [6]. It is a network of vascular channels that stabilize the cerebral blood flow when the main ducts fail [7].…”

Assessment of Cerebral Collaterals in Acute Ischemic Stroke by CT Cerebral Angiography and Its Relation to the Functional Outcome

“…In the setting of acute ischemic stroke, the extent of collateral circulation influences the size of the final infarct and the growth of the penumbra. Hence, the relationship between the collateralization grade and the predictability of infarct evolution has been a primary focus in recent years (Verma et al, 2015).…”