Judgment of FLAIR signal change in DWI–FLAIR mismatch determination is a challenge to clinicians

Ziegler, Annerose; Ebinger, Martin; Fiebach, Jochen B.; Audebert, Heinrich J.; Leistner, Stefanie

doi:10.1007/s00415-011-6284-6

Cited by 22 publications

(15 citation statements)

References 8 publications

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“…The second limitation is that the visual classification of parenchymal FLAIR lesions was based on dichotomization between positive and negative groups, which could be difficult to assess for some patients resulting in a substantial interobserver agreement. However, our interobserver agreement is similar to previous study based on FLAIR positivity [17]. This difficulty was limited by obtaining a consensus between the two readers.…”

Section: Discussionsupporting

confidence: 66%

“…The two readers first identified the DWI lesion followed by a review of the FLAIR images, focusing their analysis on the parenchymal FLAIR signal. Due to the difficulty to assess parenchymal FLAIR intensity on some lesions, in case of doubt, positivity was determined by comparison to the controlateral side [17]. The readers were instructed not to consider intravascular FLAIR signal for the classification (Fig.…”

Section: Image Analysismentioning

confidence: 99%

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Parenchymal FLAIR hyperintensity before thrombolysis is a prognostic factor of ischemic stroke outcome at 3 Tesla

Emeriau

Soize

Riffaud

et al. 2015

Journal of Neuroradiology

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Section: Discussionsupporting

confidence: 66%

Section: Image Analysismentioning

confidence: 99%

Parenchymal FLAIR hyperintensity before thrombolysis is a prognostic factor of ischemic stroke outcome at 3 Tesla

Emeriau

Soize

Riffaud

et al. 2015

Journal of Neuroradiology

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“…[2][3][4]8 This is well explained by the gradual increase in SI on FLAIR after ischemic stroke. Exterior influences such as contrast and brightness, the personality and experience of the rater, as well as lesion size and image quality are also likely to play a role, 1 as they probably did in our study as well.…”

Section: Discussionmentioning

confidence: 90%

“…However, visually judging lesion conspicuity on FLAIR is subjective and inter-rater agreements tend to be moderate, [2][3][4] whereas an automated analysis is made complicated by low contrast and partial volume effects. 5 The WAKE-UP trial 6 relies on imaging criteria for the randomization of patients; in short, a DWI-FLAIR mismatch coupled with exclusion of hemorrhage and a DWI lesion involving less than one third of the middle cerebral artery territory.…”

mentioning

confidence: 99%

Visual and Region of Interest–Based Inter-Rater Agreement in the Assessment of the Diffusion-Weighted Imaging– Fluid-Attenuated Inversion Recovery Mismatch

Galinović

Puig

Neeb

et al. 2014

Stroke

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Background and Purpose-WAKE-UP is a randomized, placebo-controlled MRI-based trial of thrombolysis in wake-up stroke using the mismatch between a lesion's visibility in diffusion-weighted imaging and fluid-attenuated inversion recovery (FLAIR) sequences as its main imaging inclusion criterion. Visual judgment of lesion conspicuity on FLAIR is however methodically limited by moderate inter-rater agreement. We therefore sought to improve rating homogeneity by incorporating quantitative signal intensity measurements. Methods-One hundred forty-three data sets of patients with acute ischemic stroke were visually rated by 8 raters with respect to WAKE-UP study inclusion and exclusion criteria, and inter-rater agreement was calculated. A subanalysis was performed on 45 cases to determine a threshold value of relative signal intensity (rSI) between the ischemic lesion and contralateral healthy tissue which best corresponded to a visually established verdict of FLAIR positivity. The usefulness of this threshold in improving inter-rater agreement was evaluated in an additional sample of 50 patients. Results-Inter-rater agreement for inclusion into the WAKE-UP trial was 73% with a free-marginal κ of 0.46. A threshold of rSI which best correlated with the visual rating of lesions as FLAIR positive was 1.20. The addition of rSI measurements to visual evaluation did not change the inter-rater agreement. Conclusions-Introducing

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“…Forth, the PWI-DWI mismatch was visually assessed, although the presence of mismatch was deduced by agreement of independent investigators. Fifth, the criteria for identifying FLAIR signal changes within DWI lesions are not yet well defined, 23 and the clinical significance of subtle or partial FLAIR changes was not evaluated. Although FLAIR-negative images are most appropriate for evaluating DWI-FLAIR mismatch, partial or subtle changes are frequently observed and may have implications for determining stroke onset.…”

Section: February 2014mentioning

confidence: 99%

Diffusion-Weighted Image and Fluid-Attenuated Inversion Recovery Image Mismatch

Kim

Lee

et al. 2014

Stroke

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A lthough ≈25% of patients with ischemic stroke become aware of stroke on awakening from sleep, international guidelines do not permit intravenous thrombolysis in these patients because of insufficient evidence of safety and efficacy.1 Studies have focused on identifying imaging biomarkers that can help to determine the actual time of stroke onset in unclear-onset stroke (UnCOS), [2][3][4][5] and therefore help to identify patients that are eligible for thrombolysis. 6,7 Previously, perfusion-weighted imaging (PWI), diffusion-weighted imaging (DWI), and fluid-attenuated inversion recovery (FLAIR) image studies suggested that the actual time of onset in many patients with wake-up stroke (WUS) may be close to the time of awakening. 2,8,9 It has been proposed recently that patients with acute ischemic lesions that are visible on DWI, but not on FLAIR images, that is, patients with DWI-FLAIR mismatch, are likely to be within the therapeutic time window (3 or 4.5 hours from stroke onset) for thrombolysis.4,5 DWI-FLAIR mismatch decreases as time passes after stroke onset, 10,11 and the time from stroke onset to MRI correlates with the FLAIR signal intensity. As the time of stroke occurrence is clear in clearonset stroke (COS), the serial changes of DWI-FLAIR mismatch in COS may be used as a time scale for estimating the stroke onset in UnCOS.With these considerations, we sought to compare the proportion of patients with DWI-FLAIR mismatch between UnCOS and COS according to the time from when the patient was first found abnormal (first-found abnormal time [FAT]) to the time MRI was performed, and we hypothesized that patients with UnCOS within a particular time window might have a similar DWI-FLAIR mismatch profile with patients with COS.Background and Purpose-Mismatch in lesion visibility between diffusion-weighted image and fluid-attenuated inversion recovery image (DWI-FLAIR mismatch) has been proposed as a biomarker for the estimation of ischemic lesion age. The actual onset in some patients with unclear-onset stroke (UnCOS) may be close to the first-found abnormal time. We hypothesized that patients with UnCOS within a particular time window might have a similar DWI-FLAIR mismatch profile with patients with clear-onset stroke (COS). Methods-Patients who underwent MRI within 6 hours from first-found abnormal time were recruited retrospectively.Clinical characteristics and the proportion of DWI-FLAIR and perfusion-weighted image-DWI mismatch in each time window were compared between UnCOS and COS. Results-The final analysis included 259 patients (114 with UnCOS and 145 with COS). Patients with UnCOS were olderand had more severe stroke at baseline. Risk factors, stroke subtypes, and perfusion-weighted image-DWI mismatch did not differ between the 2 groups. The proportion of patients with DWI-FLAIR mismatch in UnCOS did not differ from COS within 2 hours of first-found abnormal time (50.0% versus 51.5%; P=0.92), but it was significantly lower in UnCOS than in COS at 2 to 3 hours (16.1% versus 44.4%; P=0.02), 3 to 4 h...

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Judgment of FLAIR signal change in DWI–FLAIR mismatch determination is a challenge to clinicians

Cited by 22 publications

References 8 publications

Parenchymal FLAIR hyperintensity before thrombolysis is a prognostic factor of ischemic stroke outcome at 3 Tesla

Parenchymal FLAIR hyperintensity before thrombolysis is a prognostic factor of ischemic stroke outcome at 3 Tesla

Visual and Region of Interest–Based Inter-Rater Agreement in the Assessment of the Diffusion-Weighted Imaging– Fluid-Attenuated Inversion Recovery Mismatch

Diffusion-Weighted Image and Fluid-Attenuated Inversion Recovery Image Mismatch

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