Fluid-Attenuated Inversion Recovery Vascular Hyperintensity Topography, Novel Imaging Marker for Revascularization in Middle Cerebral Artery Occlusion

Abstract

Background and purpose: In acute arterial occlusion, fluid-attenuated inversion recovery vascular hyperintensity (FVH) has been linked to slow flow in leptomeningeal collaterals and cerebral hypoperfusion, but the impact on clinical outcome is still controversial. In this study, we aimed to investigate the association between FVH topography or FVH-Alberta Stroke Program Early CT Score (ASPECTS) pattern and outcome in acute M1-middle cerebral artery occlusion patients with endovascular treatment.

Methods: We included acute M1-middle cerebral artery occlusion patients treated with endovascular therapy (ET). All patients had diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery before ET. Distal FVH-ASPECTS was evaluated according to distal middle cerebral artery-ASPECT area (M1-M6) and acute DWI lesion was also reviewed. The presence of FVH inside and outside DWI-positive lesions was separately analyzed. Clinical outcome after ET was analyzed with respect to different distal FVH-ASPECTS topography.

Results: Among 101 patients who met inclusion criteria for the study, mean age was 66.2±17.8 years and median National Institutes of Health Stroke Scale was 17.0 (interquartile range, 12.0-21.0). FVH-ASPECTS measured outside of the DWI lesion was significantly higher in patients with good outcome (modified Rankin Scale [mRS] score of 0-2; 8.0 versus 4.0, P<0.001). Logistic regression demonstrated that FVH-ASPECTS outside of the DWI lesion was independently associated with clinical outcome of these patients (odds ratio, 1.3; 95% confidence interval, 1.06-1.68; P=0.013). FVH-ASPECTS inside the DWI lesion was associated with hemorrhagic transformation (odds ratio, 1.3; 95% confidence interval, 1.04-1.51; P=0.019).

Conclusions: Higher FVH-ASPECTS measured outside the DWI lesion is associated with good clinical outcomes in patients undergoing ET. FVH-ASPECTS measured inside the DWI lesion was predictive of hemorrhagic transformation. The FVH pattern, not number, can serve as an imaging selection marker for ET in acute middle cerebral artery occlusion.

Keywords: hypertension; magnetic resonance imaging; middle cerebral artery occlusion; stroke; thrombectomy.

Figure 1

Illustrative case of FVH-ASPECTS evaluation in a patient with a right MCA occlusion (A–D). No hyperintense lesions are visible in the right MCA territory (A). FVH-T-ASPECT score was 11 (M1=1, M2=2, M3=2, M4=2, M5=2, M6=2), FVH-O-ASPECTS was 11 and FVH-I-ASPECTS was 0 (B). PWI showed that mismatch on the Tmax map was congruent with the FVHs distribution(C). Abbreviations: FVH-T-ASPECTS=total FVH-ASPECT score, FVH-O-ASPECTS=FVH-ASPECT score outside DWI-positive area, FVH-I-ASPECTS=FVH-ASPECT score inside DWI-positive area

Figure 2

Location and frequencies of FVH according to the surface of distal ASPECT territories. A. Number of patients with FVHs in different ASPECT area. B. Number of patients according to different FVH distribution.

Figure 3

Representative case of prominent FVH-O-ASPECTS. A 46-years-old man with a right MCA occlusion and NIHSS of 13 on admission (A–D). Baseline total FVH-ASPECT score (B) was 11 (FVH-O-ASPECTS=9 and FVH-I-ASPECTS=2). After recanalization of the right MCA, FVH-ASPECTS decreased to 2 and no hemorrhagic transformation was found on the images (arrows on B and C). Discharge mRS of this patient was 1.

Figure 4

Representative case of prominent FVH-I-ASPECTS. A 70-years-old man with a left MCA occlusion and NIHSS of 30 on admission (A–D). Baseline total FVH-ASPECT score (B) was 10 (FVH-O-ASPECTS=5 and FVH-I-ASPECTS=5). Hemorrhagic transformation was found on the follow-up CT after recanalization (C). The hematoma shape was similar to FVH-I-ASPECTS distribution (arrows on B and C) and this patient died 4 days after admission.