Can DWI-ASPECTS Substitute for Lesion Volume in Acute Stroke?

Abstract

DiscussionAlthough each DWI-ASPECTS point corresponded to a wide range of Vol DWI , all patients with extensive changes on DWI-ASPECTS (0-3) had large Vol DWI , whereas all patients with limited DWI-ASPECTS changes (≥7) had Vol DWI <70 mL.DWI-ASPECTS is increasingly used for description or prognostic purposes in stroke populations. Although not designed to substitute for Vol DWI , DWI-ASPECTS does provide some semiquantitative estimate of it. However, DWI-ASPECTS overlooks lesions within the striatocapsular region and only partially covers the middle cerebral artery territory. This explains the wide range of true lesion volumes for a given DWI-ASPECTS point found here, in line with other studies. 2,7 Our finding that DWI-ASPECTS <4 invariably predicted Vol DWI ≥93 mL is entirely consistent with 1 previous report 7 and highly relevant to the Diffusion and perfusion imaging Evaluation For Understanding Stroke Evolution (DEFUSE)-2 malignant profile 100 mL cut point. 4 However, patients with DWI-ASPECTS ≥7 all had Vol DWI <70 mL, which corresponds to the cut point incorporated in the target mismatch definition.4 Although debated, 11 these volume cut-offs are proposed to identify poor or good responders to reperfusion therapy, 4 and particularly the 100-mL cut point serves as an exclusion criterion in several ongoing trials. However, fully automated softwares to calculate Vol DWI are not yet commonly used and can fail in real time. This may lead to imbalanced groups on baseline characteristics in trials where randomization is based on automated MR-image segmentation.14 Failure of automated volumetry may also restrain patient's inclusion in trials. To overcome these difficulties, DWI-ASPECTS <4 could replace the poorly reproducible greater than one third of the middle cerebral artery territory CT rule as an alternative exclusion criterion in MR-based trials.The tight relationships between extreme DWI-ASPECTS values (ie, <4 or ≥7) and the >100-or <70-mL, respectively, cut points found here suggest that DWI-ASPECTS could serve as a surrogate for these volumes. This concerned almost 3 quarters (241/330) of the studied population and may have clinical relevance. However, in those patients with intermediate DWI-ASPECTS (4-6), Vol DWI straddled widely across the above cut point volumes, indicating that intermediate DWI-ASPECTS cannot substitute for Vol DWI to identify patients with target mismatch or malignant profile. Of note, no DWI-ASPECTS cut point identified lesion volume >145 mL, 15 above witch decompressive hemicraniectomy is indicated.Limitations of our study include its retrospective and single-center nature, and the focus on patients who underwent thrombolysis, which limits generalizability to nonthrombolized patients and may, in part, explain the low proportion of patients with large Vol DWI and consequently the relative large 95% confidence interval for patients with low ASPECTS.In conclusion, in the first 6 hours, each DWI-ASPECTS point corresponds to a wide range of Vol DWI . However, extreme DWI-ASPECTS scor...

Outcomes Are Not Different between Patients with Intermediate and High DWI-ASPECTS after Stent-Retriever Embolectomy for Acute Anterior Circulation Stroke

“…Second, the DWI-ASPECTS cannot substitute for DWI lesion volume in patients with anterior circulation stroke and an intermediate ASPECTS of 4 -6 because an intermediate DWI-ASPECTS corresponds to a wide range of lesion volumes. 28 It has been reported that DWI lesion volume is a strong predictor of clinical outcome after endovascular treatment. 16,29 Recently, Ribo et al 29 suggested the concept of the maximal admission lesion volume compatible with favorable outcome, which was defined as the admission core volume above which the possibility of favorable outcome (mRS 0 -2) was Ͻ10% in patients with acute anterior circulation stroke.…”

“…9,14 Although the DWI-ASPECTS may not be suitable for prediction of infarction volume and outcome in patients with intermediate-to-high ASPECTS, it can still be used to predict a lesion volume cutpoint of Ͼ100 mL, which corresponds to a traditional concept of greater than one-third of the middle cerebral artery territory and serves as an exclusion criterion for endovascular therapy in ongoing trials. In a study by de Margerie-Mellon et al, 28 94% of patients (32/34) with a DWI-ASPECTS of Յ3 had a lesion volume of Ͼ100 mL and the lowest lesion volume in those patients was 93 mL. While DWI-ASPECTS may not predict outcome in patients with acute anterior circulation stroke, it may be useful for defining the presence of a benign imaging pattern to establish candidacy in the new embolectomy era.…”

“…However, a previous study showed that DWI lesion volume in patients with a DWI-ASPECTS 4 -6 ranged from 10 to 197 mL (median, 66 mL; IQR, 41-97 mL). 28 An explanation for this variability is that ASPECTS regions are weighed unequally and in favor of the striatocapsular region. 30 Another recent study showed that there is a striking disparity of DWI ASPECTS-DWI lesion volume correlations between the superficial (cortical) and the deep (striatocapsular) MCA regions.…”

Trunk Control and Lesion Locations According to Alberta Stroke Program Early CT Score in Acute Stroke: A Cross-Sectional Study

“…The scans were scored by a senior consultant neurologist (HN) at the stroke unit using the Alberta Stroke Program Early CT Score (ASPECTS). ASPECTS were initially developed for CT, but as MRI technology has rapidly become the most frequently used imaging tool, ASPECTS is applied on DWI MRI (DWI ASPECTS) [19,[25][26][27][28]. ASPECT scores 10 locations in the MCA territory [26,29]: 3 subcortical regions (internal capsule, the lentiform and caudate nuclei) and 7 cortical regions (insular cortex, M1 -M6).…”

“…two lesion locations would give an ASPECTS sum of eight. Number of lesion locations indicates the extent (size) of the lesion in the individual patient [26,30].…”