Application of FLAIR Vascular Hyperintensity-DWI Mismatch in Ischemic Stroke Depending on Semi-Quantitative DWI-Alberta Stroke Program Early CT Score

Abstract

Objective: Diffusion-weighted imaging (DWI)-Alberta Stroke Program Early CT Score (ASPECTS) is a simple, widely used method to estimate the size of the infarct. Our aim is to determine whether there is a relationship between DWI-ASPECTS and fluid-attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH)-DWI mismatch and to better quantify FVH-DWI mismatch to assess the prognosis of cerebral infarction. Materials and Methods: A retrospective analysis of 109 patients with MCA stenosis or occlusion with cerebral infarction was performed by dividing this cohort into FVH-DWI match group and FVH-DWI mismatch group based on FVH and DWI results. The clinical and imaging data of these two groups of patients were reviewed and analyzed to identify associations between FVH-DWI mismatch and prognosis of patients for preservation of neurological function. Correlation between DWI-ASPECTS and FVH-DWI mismatch was also performed. Results: FVH-DWI mismatch was present in 66/109 (60.55%) patients, and FVH-DWI match was present in 43/109 (39.45%). Patients with FVH-DWI mismatch had higher DWI-ASPECTS (7.0 vs. 4.0, P < 0.001) and lower mRS at 3 months (3.0 vs. 4.0, P < 0.001) than patients without FVH-DWI mismatch. Multiple regression analysis suggested that DWI-ASPECTS (OR = 4.7, 95% CI = 2.5-9.2, P < 0.001) remained significantly associated with FVH-DWI mismatch. Two threshold points for DWI-ASPECTS of 3 and 8 can be used to distinguish whether there is a mismatch in FVH-DWI by smooth curve fitting. Conclusions: The DWI-ASPECTS score was an independent predictor of FVH-DWI mismatch. At DWI-ASPECTS ≤ 3, the FVH-DWI mismatch offers no prognostic value; whereas, at DWI-ASPECTS ≥ 8, the FVH-DWI mismatch had the highest prognostic value. DWI-ASPECTS can roughly determine whether there is a FVH-DWI mismatch in order to select optimal clinical treatment and accurately assess prognosis.

Keywords: ASPECTS; cerebral infarction; fluid-attenuated inversion recovery vascular hyperintensity; magnetic resonance imaging; stroke.

Figure 1

Illustrative case of FVH-DWI mismatch. Magnetic resonance (MR) imaging of a 71-year-old man obtained 1 day after sudden onset of left hemiparesis. Prominent FVH on FLAIR (A–C) with small hyperintense lesions in the right MCA territory on admission DWI (D,E), which is more extensive beyond the boundaries of the DWI high signal area, indicating an FVH-DWI mismatch. Prominent FVH presents flow voids on the corresponding T₂WI image (F).

Figure 2

Illustrative case of FVH-DWI match. Magnetic resonance (MR) imaging of a 68-year-old man obtained 2 days after sudden onset of left limb paralysis and speech disorder. Partial prominent FVH on FLAIR (A–C) is more extensive within the boundaries of the DWI (D,E) high signal area, indicating an FVH-DWI match. Prominent FVH presents flow voids on the corresponding T₂WI image (F).

Figure 3

Non-linear association of the difference between DWI-ASPECTS with odds ratio of FVH outside DWI-positive area and FVH inside DWI-positive area by smoothing curve fitting.Outcome: FVH-O/I = FVH-DWI mismatch/FVH-DWI match. Exposure: DWI-ASPECTS.