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

Fluid-Attenuated Inversion Recovery May Serve As a Tissue Clock in Patients Treated With Endovascular Thrombectomy

[Figure: see text].

Modified DWI-FLAIR mismatch guided thrombolysis in unknown onset stroke

DWI-FLAIR mismatch has been recently proven to identify patients with unknown onset stroke (UOS) eligible for thrombolysis. However, this concept may exclude patients from thrombolysis who may eventually benefit as well. We aimed to examine the feasibility, safety and potential efficacy of thrombolysis in wake-up stroke (WUS) and UOS patients using a modified DWI-FLAIR mismatch allowing for partial FLAIR positivity. WUS/UOS patients fulfilling the modified DWI-FLAIR mismatch and treated with intravenous thrombolysis (IVT) were compared to propensity score matched WUS/UOS patients excluded from IVT due to FLAIR positivity. The primary endpoint was a symptomatic intracranial hemorrhage (SICH), the secondary endpoints were improvement of ≥ 4 in NIHSS score and mRS score at 3 months. 64 IVT-treated patients (median NIHSS 9) and 64 controls (median NIHSS 8) entered the analysis (p = 0.2). No significant difference in SICH was found between the IVT group and the controls (3.1% vs. 1.6%, p = 0.9). An improvement of ≥ 4 NIHSS points was more frequent in IVT patients as compared to controls (40.6% vs. 18.8%, p = 0.01). 23.4% of IVT patients achieved a mRS score of 0-1 at 3 months as compared to 18.8% of the controls (p = 0.8). SICH, improvement of NIHSS ≥ 4 and mRS 0-1 at 3 months were comparable in thrombolyzed patients with negative FLAIR images versus those thrombolyzed with partial positive FLAIR images (3% vs. 3%, p = 0.9; 40% vs. 41%, p = 0.9; 19% vs. 22%, p = 0.8). Our study signalizes that thrombolysis may be feasible in selected WUS/UOS patients with partial FLAIR signal positivity.

Bullseye's representation of cerebral white matter hyperintensities

BACKGROUND AND PURPOSE

Visual rating scales have limited capacities to depict the regional distribution of cerebral white matter hyperintensities (WMH). We present a regional-zonal volumetric analysis alongside a visualization tool to compare and deconstruct visual rating scales.

MATERIALS AND METHODS

3D T1-weighted, T2-weighted spin-echo and FLAIR images were acquired on a 3T system, from 82 elderly participants in a population-based study. Images were automatically segmented for WMH. Lobar boundaries and distance to ventricular surface were used to define white matter regions. Regional-zonal WMH loads were displayed using bullseye plots. Four raters assessed all images applying three scales. Correlations between visual scales and regional WMH as well as inter and intra-rater variability were assessed. A multinomial ordinal regression model was used to predict scores based on regional volumes and global WMH burdens.

RESULTS

On average, the bullseye plot depicted a right-left symmetry in the distribution and concentration of damage in the periventricular zone, especially in frontal regions. WMH loads correlated well with the average visual rating scores (e.g. Kendall's tau [Volume, Scheltens]=0.59 CI=[0.53 0.62]). Local correlations allowed comparison of loading patterns between scales and between raters. Regional measurements had more predictive power than global WMH burden (e.g. frontal caps prediction with local features: ICC=0.67 CI=[0.53 0.77], global volume=0.50 CI=[0.32 0.65], intra-rater=0.44 CI=[0.23 0.60]).

CONCLUSION

Regional-zonal representation of WMH burden highlights similarities and differences between visual rating scales and raters. The bullseye infographic tool provides a simple visual representation of regional lesion load that can be used for rater calibration and training.

Focal T2 and FLAIR hyperintensities within the infarcted area: A suitable marker for patient selection for treatment?

Background and purpose

Some authors use FLAIR imaging to select patients for stroke treatment. However, the effect of hyperintensity on FLAIR images on outcome and bleeding has been addressed in only few studies with conflicting results.

Methods

466 patients with anterior circulation strokes were included in this study. They all were examined with MRI before intravenous or endovascular treatment. Baseline data and 3 months outcome were recorded prospectively. Focal T2 and FLAIR hyperintensities within the ischemic lesion were evaluated by two raters, and the PROACT II classification was applied to assess bleeding complications on follow up imaging. Logistic regression analysis was used to determine predictors of bleeding complications and outcome and to analyze the influence of T2 or FLAIR hyperintensity on outcome.

Results

Focal hyperintensities were found in 142 of 307 (46.3%) patients with T2 weighted imaging and in 89 of 159 (56%) patients with FLAIR imaging. Hyperintensity in the basal ganglia, especially in the lentiform nucleus, on T2 weighted imaging was the only independent predictor of any bleeding after reperfusion treatment (33.8% in patients with vs. 18.2% in those without; p = 0.003) and there was a non-significant trend for more bleedings in patients with FLAIR hyperintensity within the basal ganglia (p = 0.069). However, there was no association of hyperintensity on T2 weighted or FLAIR images and symptomatic bleeding or worse outcome.

Conclusion

Our results question the assumption that T2 or FLAIR hyperintensities within the ischemic lesion should be used to exclude patients from reperfusion therapy, especially not from endovascular treatment.