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Association between the perfusion/diffusion and diffusion/FLAIR mismatch: data from the AXIS2 trial.

ABSTRACT: The perfusion-/diffusion-weighted imaging (PWI/DWI) mismatch and the diffusion/fluid attenuated inversion recovery (DWI/FLAIR) mismatch are magnetic resonance imaging (MRI) markers of evolving brain ischemia. We examined whether the DWI/FLAIR mismatch was independently associated with the PWI/DWI mismatch. Furthermore, we determined whether the presence of the DWI/FLAIR mismatch in patients with the PWI/DWI mismatch would provide additional information regarding last seen normal time (LTM). We used data from the 'AX200 for ischemic stroke' trial (AXIS 2 study NCT00927836). We studied the association between the presence of the DWI/FLAIR and PWI/DWI mismatch, baseline National Institute of Health Stroke Scale (NIHSS), age, ischemic-core volume, gender, intravenous (IV) tissue plasminogen activator (tPA), and perfusion-mismatch volume in univariate analysis. Significant variables (P<0.05) were added into the final multivariate model. We analyzed 197 patients. Seventy-two (37%) had both the PWI/DWI and the DWI/FLAIR mismatch. Patients with the double mismatch pattern had a shorter LTM than patients with the PWI/DWI mismatch alone (Median difference 90?minutes, P<0.01). Multivariate analysis confirmed the independent association between the two mismatch patterns (odds ratio (OR) 2.6, 95% confidence interval (CI) 1.2 to 5.4). Our study implies that the DWI/FLAIR mismatch and PWI/DWI mismatch are strongly associated, independent from LTM. Furthermore, in the presence of the PWI/DWI mismatch, the DWI/FLAIR pattern indicates a shorter LTM. This could have implications in selecting patients for reperfusion therapy.

SUBMITTER: Wouters A

PROVIDER: S-EPMC4640316 | biostudies-literature | 2015 Oct

REPOSITORIES: biostudies-literature

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Association between the perfusion/diffusion and diffusion/FLAIR mismatch: data from the AXIS2 trial.

Wouters Anke A Dupont Patrick P Ringelstein Erich B EB Norrving Bo B Chamorro Angel A Grond Martin M Laage Rico R Schneider Armin A Wilms Guido G Thomalla Götz G Lemmens Robin R Thijs Vincent N VN

Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism 20150603 10

The perfusion-/diffusion-weighted imaging (PWI/DWI) mismatch and the diffusion/fluid attenuated inversion recovery (DWI/FLAIR) mismatch are magnetic resonance imaging (MRI) markers of evolving brain ischemia. We examined whether the DWI/FLAIR mismatch was independently associated with the PWI/DWI mismatch. Furthermore, we determined whether the presence of the DWI/FLAIR mismatch in patients with the PWI/DWI mismatch would provide additional information regarding last seen normal time (LTM). We u ...[more]

PMID: 26036936

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Project description:Background and purposeThe T2-FLAIR mismatch sign on MR imaging is a highly specific imaging biomarker of isocitrate dehydrogenase (IDH)-mutant astrocytomas, which lack 1p/19q codeletion. However, most studies using the T2-FLAIR mismatch sign have used visual assessment. This study quantified the degree of T2-FLAIR mismatch using digital subtraction of fluid-nulled T2-weighted FLAIR images from non-fluid-nulled T2-weighted images in human nonenhancing diffuse gliomas and then used this information to assess improvements in diagnostic performance and investigate subregion characteristics within these lesions.Materials and methodsTwo cohorts of treatment-naïve, nonenhancing gliomas with known IDH and 1p/19q status were studied (n = 71 from The Cancer Imaging Archive (TCIA) and n = 34 in the institutional cohort). 3D volumes of interest corresponding to the tumor were segmented, and digital subtraction maps of T2-weighted MR imaging minus T2-weighted FLAIR MR imaging were used to partition each volume of interest into a T2-FLAIR mismatched subregion (T2-FLAIR mismatch, corresponding to voxels with positive values on the subtraction maps) and nonmismatched subregion (T2-FLAIR nonmismatch corresponding to voxels with negative values on the subtraction maps). Tumor subregion volumes, percentage of T2-FLAIR mismatch volume, and T2-FLAIR nonmismatch subregion thickness were calculated, and 2 radiologists assessed the T2-FLAIR mismatch sign with and without the aid of T2-FLAIR subtraction maps.ResultsThresholds of ≥42% T2-FLAIR mismatch volume classified IDH-mutant astrocytoma with a specificity/sensitivity of 100%/19.6% (TCIA) and 100%/31.6% (institutional); ≥25% T2-FLAIR mismatch volume showed 92.0%/32.6% and 100%/63.2% specificity/sensitivity, and ≥15% T2-FLAIR mismatch volume showed 88.0%/39.1% and 93.3%/79.0% specificity/sensitivity. In IDH-mutant astrocytomas with ≥15% T2-FLAIR mismatch volume, T2-FLAIR nonmismatch subregion thickness was negatively correlated with the percentage T2-FLAIR mismatch volume (P < .0001) across both cohorts. The percentage T2-FLAIR mismatch volume was higher in grades 3-4 compared with grade 2 IDH-mutant astrocytomas (P < .05), and ≥15% T2-FLAIR mismatch volume IDH-mutant astrocytomas were significantly larger than <15% T2-FLAIR mismatch volume IDH-mutant astrocytoma (P < .05) across both cohorts. When evaluated by 2 radiologists, the additional use of T2-FLAIR subtraction maps did not show a significant difference in interreader agreement, sensitivity, or specificity compared with a separate evaluation of T2-FLAIR and T2-weighted MR imaging alone.ConclusionsT2-FLAIR digital subtraction maps may be a useful, automated tool to obtain objective segmentations of tumor subregions based on quantitative thresholds for classifying IDH-mutant astrocytomas using the percentage T2 FLAIR mismatch volume with 100% specificity and exploring T2-FLAIR mismatch/T2-FLAIR nonmismatch subregion characteristics. Conversely, the addition of T2-FLAIR subtraction maps did not enhance the sensitivity or specificity of the visual T2-FLAIR mismatch sign assessment by experienced radiologists.

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Project description:Background and purposeStandard selection criteria for revascularization therapy usually exclude patients with unclear-onset stroke. Our aim was to evaluate the efficacy and safety of revascularization therapy in patients with unclear-onset stroke in the anterior circulation and to identify the predictive factors for favorable clinical outcome.Materials and methodsWe retrospectively analyzed 41 consecutive patients presenting with acute stroke with unknown time of onset treated by intravenous thrombolysis and/or mechanical thrombectomy. Only patients without well-developed fluid-attenuated inversion recovery changes of acute diffusion lesions on MR imaging were enrolled. Twenty-one patients were treated by intravenous thrombolysis; 19 received, simultaneously, intravenous thrombolysis and mechanical thrombectomy (as a bridging therapy); and 1 patient, endovascular therapy alone. Clinical outcome was evaluated at 90 days by using the mRS. Mortality and symptomatic intracranial hemorrhage were also reported.ResultsMedian patient age was 72 years (range, 17-89 years). Mean initial NIHSS score was 14.5 ± 5.7. Successful recanalization (TICI 2b-3) was assessed in 61% of patients presenting with an arterial occlusion, symptomatic intracranial hemorrhage occurred in 2 patients (4.9%), and 3 (7.3%) patients died. After 90 days, favorable outcome (mRS 0-2) was observed in 25 (61%) patients. Following multivariate analysis, initial NIHSS score (OR, 1.43; 95% CI, 1.13-1.82; P = .003) and bridging therapy (OR, 37.92; 95% CI, 2.43-591.35; P = .009) were independently associated with a favorable outcome at 3 months.ConclusionsThe study demonstrates the safety and good clinical outcome of acute recanalization therapy in patients with acute stroke in the anterior circulation and an unknown time of onset and a DWI/FLAIR mismatch on imaging. Moreover, bridging therapy versus intravenous thrombolysis alone was independently associated with favorable outcome at 3 months.

Dataset Information

Association between the perfusion/diffusion and diffusion/FLAIR mismatch: data from the AXIS2 trial.

Publications

Association between the perfusion/diffusion and diffusion/FLAIR mismatch: data from the AXIS2 trial.

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