Article Figures & Data
Figures
- Fig 1.
CTA CS. CTA CS methodology as proposed by Tan et al.9 Axial 20-mm maximum-intensity-projection images demonstrate the extent and asymmetry in the peripheral leptomeningeal collateral supply graded as relative to the contralateral normal hemisphere (pathologic MCA territory indicated by a red ROI). A, A score of zero suggests near-complete absence of surface collateralization. B, A score of 1 indicates greater than zero but <50% collateral flow. C, A score of 2 suggests >50% but <100% of normal leptomeningeal collaterals. D, A score of 3 suggests normal or, when present, greater than normal surface collaterals.
- Fig 2.
RAPID CTP core-penumbra mismatch. Sample output from RAPID perfusion module. The upper of 2 perfusion slabs (4-cm supratentorial coverage across 8 contiguous 5-mm sections) underwent delay-insensitive deconvolution, normalization and lesion segmentation, and thresholding for the production of infarct core and hypoperfused tissue estimates. Similar analysis was undertaken for the inferior perfusion slab (not shown) and cumulative predicted core and penumbral volumes established for each patient. Default output parameters for infarct core (rCBV <30%, A), infarct core (rCBF <30%, B), and hypoperfused tissues (Tmax >6 seconds, C) are shown. The final infarct volume (not shown) measured 97 mL.
- Fig 3.
Analysis pipeline, final infarct volume. Postprocessing steps for determination of final infarction volume on follow-up. Optimization of image contrast for intensity-wise lesion segmentation was performed with manual thresholding toward production of a binary image, with cross-reference to the original DWI data to exclude spurious areas related to susceptibility or EPI distortions.
Tables
Variable Odds Ratio 95% CI P Value Final infarct volume 0.84 0.72–0.98 .03 NCCT-ASPECTS 3.23 1.09–9.54 003 CBV-ASPECTS 1.78 1.13–2.80 .01 CBF-ASPECTS 1.46 1.01–2.11 .05 Collateral score 2.27 0.88–5.83 .09b Clot burden score 1.66 1.07–2.59 .02 RAPID rCBV core 0.92 0.86–0.98 .01 RAPID rCBF core 0.92 0.85–0.99 .02 RAPID Tmax >4 sec 0.98 0.96–0.99 .03 RAPID Tmax >6 sec 0.98 0.97–0.99 .01 RAPID Tmax >8 sec 0.98 0.96–1.00 .06b RAPID Tmax >10 sec 0.98 0.96–1.00 .06b ↵a NCCT-ASPECTS, CBV-ASPECTS, and CBF-ASPECTS represent ASPECTS applied respectively to noncontrast CT, cerebral blood volume maps, or cerebral blood flow maps.
↵b Statistical significance in logistic regression observed with all tested variables with the exception of RAPID-derived Tmax of >8 seconds and >10 seconds and the CTA collateral score (P > .05).
Variable AUC P Value 95% CI OOP Sensitivity Specificity Final infarct (mL) 0.96 <.001 0.91–1.00 29.1 91% 88% RAPID rCBV core 0.86 .001 0.74–0.96 10.4 85% 78% RAPID rCBF core 0.81 <.001 0.68–0.93 5.6 73% 72% RAPID Tmax >4 sec 0.80 <.01 0.65–0.93 146.6 73% 67% RAPID Tmax >6 sec 0.77 <.01 0.63–0.92 81.9 77% 72% RAPID Tmax >8 sec 0.76 <.01 0.60–0.91 53.1 77% 72% RAPID Tmax >10 sec 0.74 <.01 0.58–0.89 26.6 73% 72% NCCT-ASPECTS 0.72 .01 0.57–0.87 9.5 68% 68% CBV-ASPECTS 0.75 .01 0.61–0.89 5.0 76% 62% CBF-ASPECTS 0.72 .02 0.57–0.87 5.0 58% 66% Clot burden score 0.74 .01 0.59–0.89 6.5 58% 77% Collateral scoreb .72 .20 0.56–0.89 1.5 70% 70% Note:—OOP indicates optimal operating point, optimal cut-off from ROC analysis for the variable of interest.
↵a Results of ROC analysis relative to dichotomized favorable clinical outcome (90-day mRS ≤2). Performance indicated by ROC AUC in descending-order performance.
↵b Significant relationships were observed for all tested variables, with the exception of the CTA collateral score.
Variable Correlation P Value RAPID rCBV core 0.77 <.001 RAPID rCBF core 0.75 <.001 RAPID Tmax >4 sec 0.38 <.01 RAPID Tmax >6 sec 0.44 <.001 RAPID Tmax >8 sec 0.49 <.001 RAPID Tmax >10 sec 0.54 <.001 NCCT-ASPECTS −0.40 <.01 CBV-ASPECTS −0.50 <.001 CBF-ASPECTS −0.48 <.001 Clot burden scoreb −0.23 .11 Collateral score −0.41 <.01 ↵a Correlational analysis between tested variables and final infarct volume (MRI or CT, in milliliters). The strongest overall correlations were observed with RAPID-derived core estimates (rCBF core and rCBV core). Negative correlations were observed between all ASPECTS and CTA-derived measures relative to the final infarct volume.
↵b Significant relationships were observed for all tested variables with the exception of the CTA clot burden score.
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