Hyperintense Vessels on FLAIR: Hemodynamic Correlates and Response to Thrombolysis

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Fig 1.
MR imaging (left-to-right: acute FLAIR, acute DWI, acute Tmax, dichotomized Tmax, follow-up DWI) of patients with middle cerebral artery occlusions (M1). Patient A (82 years of age; baseline NIHSS score, 13; baseline lesion volume, 1.4 mL; HIR, 0.031; recanalization to Thrombolysis in Myocardial Infarction 2 following treatment; absolute infarct growth, 3.3 mL) had FLAIR hyperintense vessels on 3 sections (FHV ≤ 4; not visible on the depicted section) and patient B (76 years of age; baseline NIHSS score, 23; baseline lesion volume, 63.8 mL; HIR, 0.53; no recanalization following treatment [Thrombolysis in Myocardial Infarction, 0]; absolute infarct growth, 80.2 mL) had FHV on 8 sections (arrows; FHV > 4).

Table 1:

Comparison of baseline parameters and response to thrombolysis based on the number of sections with FLAIR hyperintense vessels^{^a}

	Visible FHV on ≤4 Sections	Visible FHV on >4 Sections	P Value
No.	30	32
Age (yr) (mean) (SD)	71 (10.8)	71.9 (16.5)	.42
Time to MRI in min (median) (IQR)	88.5 (72–103)	93.5 (61–121)	.98
NIHSS score on admission (median) (IQR)	5 (4–13)	14.5 (11–18)	<.001
NIHSS score on day 2 (median) (IQR)	3 (1–5)	5 (2–17)	.03
TOAST			.05
Cardioembolic (%) (No.)	40.7 (11)	36.7 (11)
Macroangiopathic (%) (No.)	37 (10)	63.3 (19)
Microangiopathic (%) (No.)	0 (0)	0 (0)
Other (%) (No.)	7.4 (2)	0 (0)
Competing causes (%) (No.)	14.8 (4)	0 (0)
Baseline lesion volume (mL) (median) (IQR)	1.6 (.3–4.9)	8.1 (2.4–20.6)	<.01
Infarct growth (median) (IQR)	1.2 (0.2–12.7)	12.8 (2.5–43.9)	<.01
Perfusion-diffusion mismatch (%) (No.)	67.7 (21)	96.9 (31)	<.01
Baseline perfusion deficit (mL) (median) (IQR)	24.8 (14.5–54.6)	118 (82–175)	<.001
Tmax ≥2 sec	30 (16.7–97.1)	155 (115.7–191.2)	<.001
Tmax ≥8 sec	10.3 (3.7–27.2)	87.2 (62.5–123.7)	<.001
HIR	0.28 (0.07–0.47)	0.61 (0.44–0.73)	<.01
Vessel occlusion size:			.29
Large (%) (No.)	20 (6)	9.4 (3)
Medium (%) (No.)	80 (24)	90.6 (29)
Small (%) (No.)	0 (0)	0 (0)
Recanalization (%) (No.)	53.3 (16)	74.2 (23)	.11
Favorable outcome at 3 months (%) (No.)	66.7 (20)	38.7 (12)	.02

↵a A Fisher exact test and Mann-Whitney U test were used for categoric and continuous variables, respectively.

Table 2:

Univariate analysis comparing patients with moderate hypoperfusion (HIR ≤ 0.447) with patients with severe hypoperfusion (HIR > 0.447)^{^a}

	Low HIR (≤0.447)	High HIR (>0.447)	P Value
No.	31	31
Age (yr) (mean) (SD)	67.5 (13.2)	75.4 (13.7)	.02
Female (%) (No.)	51.6 (16)	45.2 (14)	.8
Arterial hypertension (%) (No.)	80.6 (25)	87.1 (27)	.73
Diabetes mellitus (%) (No.)	16.1 (5)	25.8 (8)	.53
Smoking (%) (No.)	38.7 (12)	9.7 (3)	.02
Hypolipoproteinemia (%) (No.)	54.8 (17)	46.4 (15)	.9
Atrial fibrillation (%) (No.)	35.5 (11)	45.2 (14)	.6
No. of sections with FHV (median) (IQR)	3 (1–7)	7 (4–10)	<.01
NIHSS score on admission (median) (IQR)	5 (4–13)	15 (11–18)	<.001
Baseline lesion volume (mL) (median) (IQR)	1.5 (0.27–5.8)	6.7 (2.3–28.2)	<.01
Infarct growth (median) (IQR)	1.6 (0.2–10.6)	6.2 (1.4–39.0)	<.01
Baseline perfusion deficit (mL) (median) (IQR)	41.2 (15.8–101.7)	117.1 (56.0–171.6)	<.01
Tmax ≥ 2 sec	75.6 (24.7–179.4)	143.1 (70.5–170.2)	.08
Tmax ≥ 8 sec	10.5 (3.7–61.9)	88.2 (43.7–122.6)	<.001
Vessel-occlusion size:			.47
Large (%) (No.)	19.4 (6)	9.7 (3)
Medium (%) (No.)	80.6 (25)	90.3 (28)
Small (%) (No.)	0 (0)	0 (0)
Recanalization (%) (No.)	70 (21)	58.1 (18)	.43
Favorable outcome at 3 months (%) (No.)	75.9 (22)	32.3 (10)	<.01

↵a A Fisher exact test and Mann-Whitney U test were used for categoric and continuous variables, respectively.

Table 3:

Stepwise multivariate regression analysis for severity of hypoperfusion (dichotomized at median)

	Odds Ratio	95% CI	P Value	Univariate r²
First step (multivariate r² = 0.68)
Age	1.2	1.0–1.3	.01	0.12
TOAST	0.76	0.15–4.2	.77	0.004
Baseline lesion volume	1.1	1.0–1.2	.04	0.12
Baseline perfusion deficit	1.0	0.99–1.0	.06	0.12
Sections with FHV (>4)	6.7	1.0–41.9	.04	0.26
Smoking	0.04	0.001–0.99	.05	0.14
Last step (multivariate r² = 0.68)
Age	1.2	1.0–1.3	.01
Baseline lesion volume	1.1	1.0–1.2	.05
Baseline perfusion deficit	1.01	0.9–1.0	.06
Smoking	0.04	0.001–0.96	.05
Sections with FHV (>4)	6.8	1.1–42.7	.04

Table 4:

Stepwise multivariate regression analysis for favorable outcome (mRS ≤2)

	Odds Ratio	95% CI	P Value	Univariate r²
First step (multivariate r² = 0.42)
Age (older than 70 years)	1.0	0.23–5.8	.95	0.0
Smoking	0.84	0.20–4.5	.83	0.02
Atrial fibrillation	0.41	0.10–1.6	.21	0.14
Sections with FHV (>4)	0.89	0.2–3.9	.88	0.12
HIR (>0.447)	0.24	0.05–1.1	.07	0.24
NIHSS score on admission	0.93	0.83–1.0	.12	0.25
Baseline lesion volume	0.96	0.90–1.0	.12	0.21
Last step (multivariate r² = 0.36)
HIR (>0.447)	0.17	0.05–0.57	< .01
Baseline lesion volume	0.95	0.90–1.0	.05