Table 3. ROC analysis of CTASI-rHU values for the classification of indicated parameters.
| Location | AUC (95% CI) | P Value | Youden’s Index | Associated Cut-Off Value (rHU) | Associated Sensitivity | Associated Specificity | |
|---|---|---|---|---|---|---|---|
| Classification of Regional CT Perfusion-Based Ischemia | |||||||
| C | 0.87 | (0.78–0.94) | <0.001 | 0.60 | 0.947 | 92% (36/39) | 68% (27/40) |
| IC | 0.87 | (0.78–0.94) | <0.001 | 0.67 | 0.919 | 79% (30/38) | 88% (35/41) |
| INS | 0.95 | (0.87–0.98) | <0.001 | 0.91 | 0.972 | 91% (68/75) | 100% (4/4) |
| L | 0.89 | (0.80–0.95) | <0.001 | 0.70 | 0.873 | 85% (34/40) | 85% (33/39) |
| M1 | 0.84 | (0.74–0.91) | <0.001 | 0.58 | 0.933 | 69% (48/70) | 89% (8/9) |
| M2 | 0.93 | (0.86-0-98) | <0.001 | 0.86 | 0.941 | 86% (65/76) | 100% (3/3) |
| M3 | 0.85 | (0.75–0.92) | <0.001 | 0.60 | 0.976 | 67% (42/63) | 94% (15/16) |
| M4 | 0.72 | (0.61–0.81) | 0.002 | 0.34 | 0.953 | 47% (28/64) | 87% (13/15) |
| M5 | 0.99 | (0.94–1.00) | <0.001 | 0.99 | 0.991 | 99% (75/76) | 100% (3/3) |
| M6 | 0.80 | (0.69–0.88) | <0.001 | 0.48 | 0.977 | 64% (43/67) | 83% (10/12) |
| Classification of Regional CT Perfusion-Based Ischemic Core | |||||||
| C | 0.85 | (0.75–0.92) | <0.001 | 0.68 | 0.884 | 95% (18/19) | 73% (44/60) |
| IC | 0.75 | (0.64–0.84) | <0.001 | 0.51 | 0.904 | 77% (17/22) | 74% (42/57) |
| INS | 0.69 | (0.57–0.79) | 0.003 | 0.35 | 0.803 | 65% (30/46) | 70% (23/33) |
| L | 0.87 | (0.77–0.93) | <0.001 | 0.64 | 0.837 | 82% (22/27) | 83% (43/52) |
| M1 | 0.72 | (0.61–0.82) | 0.001 | 0.39 | 0.889 | 52% (11/21) | 86% (51/58) |
| M2 | 0.70 | (0.59-0-80) | 0.001 | 0.47 | 0.878 | 73% (22/30) | 74% (36/49) |
| M3 | 0.67 | (0.56–0.78) | 0.08 | 0.45 | 0.953 | 73% (8/11) | 72% (49/68) |
| M4 | 0.68 | (0.57–0.78) | 0.01 | 0.36 | 0.945 | 58% (11/19) | 78% (47/60) |
| M5 | 0.55 | (0.43–0.66) | 0.45 | 0.17 | 0.958 | 94% (31/32) | 23% (11/47) |
| M6 | 0.75 | (0.63–0.84) | 0.001 | 0.60 | 0.966 | 82% (14/17) | 77% (48/62) |
| Prediction of Final Infarction | |||||||
| C | 0.87 | (0.78–0.94) | <0.001 | 0.71 | 0.923 | 97% (32/33) | 73% (34/46) |
| IC | 0.71 | (0.59–0.80) | <0.001 | 0.36 | 0.955 | 96% (21/22) | 40% (23/57) |
| INS | 0.65 | (0.54–0.76) | 0.01 | 0.24 | 0.781 | 49% (21/43) | 75% (27/36) |
| L | 0.81 | (0.71–0.89) | <0.001 | 0.55 | 0.876 | 77% (33/43) | 78% (28/36) |
| M1 | 0.71 | (0.60–0.81) | 0.07 | 0.37 | 0.880 | 47% (9/19) | 90% (54/60) |
| M2 | 0.65 | (0.54–0.76) | 0.02 | 0.32 | 0.859 | 59% (16/27) | 73% (38/52) |
| M3 | 0.72 | (0.61–0.82) | <0.001 | 0.40 | 0.957 | 68% (13/19) | 72% (43/60) |
| M4 | 0.68 | (0.57–0.78) | 0.03 | 0.38 | 0.945 | 58% (11/19) | 80% (48/60) |
| M5 | 0.60 | (0.49–0.71) | 0.13 | 0.28 | 0.887 | 41% (13/32) | 87% (41/47) |
| M6 | 0.72 | (0.61–0.81) | 0.002 | 0.37 | 0.942 | 63% (10/16) | 75% (48/63) |
rHU was defined as the ratio of regional x-ray attenuation measurements of the ischemic to the non-ischemic hemisphere. Ischemic core was defined as ischemic change on the parametric cerebral blood flow map as well as cerebral blood volume map. Sensitivity and specificity for the indicated cut-off value are presented as percentage and numbers as raw data in parentheses. AUC indicates area under the curve values; C, caudate nucleus; CI, confidence interval; IC, internal capsule; INS, insula; L, lentiform nucleus; M1-M6, cortical regions of the ASPECTS score; rHU, relative Hounsfield Units; and ROC, receiver operating characteristics. P Values <0.05 indicate statistical significance.