Article Figures & Data
- Figure 1
Representative cases with unilateral ICA (A) or MCA (B–D) occlusion presenting different ASL-collateral grades. (A) G0, indicating no ATA in the downstream hypoperfusion abnormality. (B) G1 suggesting minimal ATA (arrow) distribution of less than 1/2 downstream hypoperfusion region. (C) G2, suggesting moderate ATA distribution of more than 1/2 downstream hypoperfusion region. (D) G3, suggesting normal perfusion without downstream ATA. Arrows indicate ATA. ASL, arterial spin labelling; ATA, arterial transit artifact; ICA, internal carotid artery; MCA, middle cerebral artery.
- Figure 2
Correlation analysis of variables. (A) Correlations between FVH-ASPECTS, ASL-collateral grade and age in all patients. (B) Correlations between FVH-ASPECTS, ASL-collateral grade and event-to-imaging time in the symptomatic occlusion group. ASL, arterial spin labelling; ASPECTS, Alberta Stroke Program Early Computed Tomography Score; FVH, fluid-attenuated inversion recovery vascular hyperintensity.
- Figure 3
Association between FVH-ASPECTS, ASL-collateral grade and probability of symptomatic occlusion of the internal carotid artery or middle cerebral artery. (A) Three-dimensional scatterplots with fitted surfaces illustrate the association between FVH-ASPECTS, ASL-collateral grade and the probability of symptomatic occlusion in the multivariate logistic regression. (B) Receiver operating characteristic curve and precision-recall curve of FVH-ASPECTS in identifying symptomatic occlusion of the internal carotid artery or middle cerebral artery. Distribution of FVH-ASPECTS dichotomised by ≥2 (C) and each ASL-collateral grade (D) along with the increasing probability of symptomatic status is presented. ASL, arterial spin labelling; ASPECTS, Alberta Stroke Program Early Computed Tomography Score; FVH, fluid-attenuated inversion recovery vascular hyperintensity; N, negative; P, positive; ROC, receiver operating characteristic.
- Figure 4
Symptomatic status comparison between subgroups. (A) Comparison of the proportions of the index events between subgroups of FVH, ATA, ASL-collateral grade, occlusive site and sex. P value indicates results for χ2 test of the proportion of TIA, acute stroke, non-acute stroke and asymptomatic occlusion between groups. (B) Representative cases illustrate the extent of FVH in ipsilateral middle cerebral artery occlusions with acute stroke, non-acute stroke, TIA and asymptomatic status. Arrows indicate FVH. ASL, arterial spin labelling; ASPECTS, Alberta Stroke Program Early Computed Tomography Score; ATA, arterial transit artifact; DWI, diffusion-weighted imaging; FLAIR, fluid-attenuated inversion recovery; FVH, fluid-attenuated inversion recovery vascular hyperintensity; ICA, internal carotid artery; MCA, middle cerebral artery; MRA, MR angiography; TIA, transit ischaemic attack.
- Table 1
Comparison of clinical and imaging characteristics between symptomatic and asymptomatic occlusions
Total
(n=149)Asymptomatic occlusion (n=37) Symptomatic occlusion (n=112) P value Sex (Females), n (%) 35 4 (10.81%) 31 (27.68%) 0.037 Age, years 60.43±12.83 56.62±10.81 61.69±13.23 0.037 Risk factors, n (%) Hypertension 88 21 (56.76%) 67 (59.82%) 0.743 Diabetes 30 10 (27.03%) 20 (17.09%) 0.229 Lipid disorders 44 9 (24.32%) 35 (31.25%) 0.425 Coronary artery disease 21 4 (10.81%) 17 (15.18%) 0.509 Smoking history 61 17 (45.95%) 44 (39.29%) 0.477 Occlusive site, n (%) 0.098 MCA 78 15 (40.54%) 63 (56.25%) ICA 71 22 (59.46%) 49 (43.75%) FVH-ASPECTS, median (IQR) 2 (1–3) 0 (0–1) 3 (1–4) <0.0001 ASL-collateral circulation, median (IQR) 2 (1–3) 3 (2–3) 1 (1–2) <0.0001 ASL, arterial spin labelling; ASPECTS, Alberta Stroke Program Early Computed Tomography Score; FVH, fluid-attenuated inversion recovery vascular hyperintensity; ICA, internal carotid artery; MCA, middle cerebral artery.
- Table 2
Factors associated with symptomatic status in intracranial ICA or MCA occlusion
Parameter Univariate Multivariate OR (95% CI) P value OR (95% CI) P value Age (per year) 1.033 (1.002 to 1.065) 0.038 0.999 (0.957 to 1.042) 0.952 Sex (male vs female) 3.157 (1.033 to 9.650) 0.044 1.493 (0.374 to 5.962) 0.571 Occlusive site (MCA vs ICA) 1.886 (0.886 to 4.012) 0.100 1.491 (0.546 to 4.069) 0.436 FVH-ASPECTS (per score) 3.420 (2.179 to 5.368) <0.0001 2.973 (1.849 to 4.781) <0.0001 ASL-collateral circulation (per grade) 0.441 (0.294 to 0.662) 0.001 0.735 (0.453 to 1.193) 0.213 ASL, arterial spin labelling; ASPECTS, Alberta Stroke Program Early Computed Tomography Score; CI, Confidence interval; FVH, fluid-attenuated inversion recovery vascular hyperintensity; ICA, internal carotid artery; MCA, middle cerebral artery; OR, Odd ratio.
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