Table 3.
Performance of indicated parameters for the detection of LVO stroke patients
| Method/cut point | Sensitivity (95% CI) [raw #] |
Specificity (95% CI) [raw #] |
PPV* | NPV* |
|---|---|---|---|---|
| Overall LVO Stroke Patients (n = 79) vs. Controls (n = 66) | ||||
| CTA Hemispheric AR | ||||
|
Y‑Index CP = 0.926 |
0.87 (0.78–0.94) [69/79] |
0.97 (0.90–1.00) [64/66] |
0.93 (0.76–0.98) | 0.95 (0.91–0.97) |
|
Specificity ≥0.70 CP = 0.955 |
0.96 (0.89–0.99) [76/79] |
0.77 (0.65–0.87) [51/66] |
0.65 (0.54–0.74) | 0.98 (0.94–0.99) |
| CTA Min/Max AR Ratio | ||||
|
Y‑Index CP = 0.810 |
0.90 (0.81–0.96) [71/79] |
0.99 (0.92–1.00) [64/66] |
0.96 (0.78–0.99) | 0.96 (0.92–0.98) |
|
Specificity ≥0.70 CP = 0.889 |
0.95 (0.88–0.99) [75/79] |
0.83 (0.72–0.91) [55/66] |
0.71 (0.59–0.81) | 0.98 (0.94–0.99) |
| CTA M2 Territory Asymmetry Ratio | ||||
|
Y‑Index CP = 0.922 |
0.87 (0.80–0.95) [69/79] |
0.97 (0.90–1.00) [65/66] |
0.93 (0.76–0.98) | 0.95 (0.91–0.97) |
|
Specificity ≥0.70 CP = 0.941 |
0.91 (0.83–0.96) [72/79] |
0.83 (0.72–0.91) [55/66] |
0.70 (0.58–0.80) | 0.96 (0.92–0.99) |
| ICA + M1-Occlusion (n = 72) vs. Controls (n = 66) | ||||
| CTA Hemispheric AR | ||||
|
Y‑Index CP = 0.926 |
0.92 (0.83–0.97) [66/72] |
0.97 (0.90–1.00) [64/66] |
0.93 (0.77–0.98) | 0.96 (0.93–0.98) |
|
Specificity ≥0.70 CP = 0.955 |
0.99 (0.93–1.000) [71/72] |
0.77 (0.65–0.87) [51/66] |
0.65 (0.54–0.74) | 0.99 (0.95–1.00) |
| CTA Min/Max AR Ratio | ||||
|
Y‑Index CP = 0.810 |
0.93 (0.85–0.97) [67/72] |
0.99 (0.92–1.00) [65/66] |
0.96 (0.79–1.00) | 0.97 (0.93–0.99) |
|
Specificity ≥0.70 CP = 0.955 |
0.97 (0.90–1.00) [70/72] |
0.88 (0.78–0.95) [58/66] |
0.78 (0.64–0.87) | 0.99 (0.95–1.00) |
| CTA M2 Territory AR | ||||
|
Y‑Index CP = 0.922 |
0.90 (0.83–0.97) [65/72] |
0.97 (0.90–1.00) [64/66] |
0.93 (0.77–0.98) | 0.96 (0.93–0.98) |
|
Specificity ≥0.70 CP = 0.955 |
0.93 (0.85–0.98) [67/72] |
0.83 (0.72–0.91) [55/66] |
0.71(0.58–0.81) | 0.97 (0.92–0.99) |
| M2 Occlusions (n = 7) vs. Controls (n = 66) | ||||
| CTA Hemispheric AR | ||||
|
Y‑Index CP = 0.935 |
0.57 (0.18–0.90) [4/7] |
0.94 (0.85–0.98) [62/66] |
0.28 (0.11–0.55) | 0.98 (0.96–0.99) |
|
Specificity ≥0.70 CP = 0.955 |
0.71 (0.20–0.96) [5/7] |
0.77 (0.65–0.87) [51/66] |
0.12 (0.06–0.20) | 0.99 (0.95–1.00) |
| CTA Min/Max AR Ratio | ||||
|
Y‑Index CP = 0.785 |
0.57 (0.18–0.90) [4/7] |
1.0 (0.95–1.00) [66/66] |
1.00 (1.00–1.00) | 0.98 (0.96–0.99) |
|
Specificity ≥0.70 CP = 0.889 |
0.71 (0.29–0.96) [5/7] |
0.83 (0.72–0.91) [51/66] |
0.15 (0.08–0.27) | 0.99 (0.96–1.00) |
| CTA M2 Territory AR | ||||
|
Y‑Index CP = 0.941 |
0.71 (0.29–0.96) [5/7] |
0.83 (0.72–0.91) [55/66] |
0.15 (0.08–0.27) | 0.99 (0.96–1.00) |
|
Specificity ≥0.70 (same as above) |
0.71 (0.29–0.96) [5/7] |
0.83 (0.72–0.91) [55/66] |
0.15 (0.08–0.27) | 0.99 (0.96–1.00) |
| CTA M5 ASPECTS Region AR | ||||
|
Y‑Index CP = 0.919 |
0.86 (0.42–1.00) [6/7] |
0.92 (0.83–0.98) [61/66] |
0.32 (0.16–0.54) | 0.99 (0.96–1.00) |
|
Specificity ≥0.70 (same as above) |
0.86 (0.42–1.00) [6/7] |
0.92 (0.83–0.98) [61/66] |
0.32 (0.16–0.54) | 0.99 (0.96–1.00) |
Performance metrics for the indicated parameters are displayed as value (95%-CI) [raw numbers]. CP were determined by the Y‑Index and sensitivity threshold of ≥0.70. To calculate PPV and NPV a rate of overall LVO stroke patients of 30% and specifically M2 occlusion patients of 4% was assumed
LVO indicates large-vessel occlusion, CI confidence interval, PPV positive predictive value, NPV negative predictive value, Y‑Index Youden Index, CP cut point, Spec specificity, CTA CT angiography, AR asymmetry ratio, ICA internal carotid artery, M1 M1 segment of the middle cerebral artery, M2 M2 segment of the middle cerebral artery, ASPECTS Alberta Stroke Program Early CT Score