Accuracy, sensitivity, specificity, NPV, and PPV of the different imaging techniques for the diagnosis of angiographic vasospasm
| Presence or Absence of Angiographic Vasospasm | DSA Gold Standard | TCD Absolute FV (cm/s) | TCD EICA Ratios | NCT Hypodensities | CTA | PCT rCBV (cc × 100 g−1) | PCT rCBF (cc × 100 g−1 × min−1) | PCT MTT (s) | PCT TTP (s) |
|---|---|---|---|---|---|---|---|---|---|
| Thresholds | >120 | >3.00 | Presence or Absence | Presence or Absence | <4.4 | <44.3 | >6.4 | >24.4 | |
| TN | 507 | 449 | 455 | 498 | 483 | 378 | 477 | 460 | 452 |
| FP | 0 | 58 | 52 | 9 | 24 | 129 | 30 | 747 | 55 |
| FN | 0 | 40 | 35 | 108 | 30 | 89 | 24 | 6 | 16 |
| TP | 123 | 83 | 88 | 15 | 93 | 34 | 99 | 117 | 107 |
| Accuracy | 100.0% | 84.4% | 86.2% | 81.4% | 91.4% | 65.4% | 91.4% | 91.6% | 88.7% |
| Sensitivity | 100.0% | 67.5% | 71.5% | 12.2% | 75.6% | 27.6% | 80.5% | 95.1% | 87.0% |
| Specificity | 100.0% | 88.6% | 89.7% | 98.2% | 95.3% | 74.6% | 94.1% | 90.7% | 89.2% |
| NPV | 100.0% | 91.8% | 92.9% | 82.2% | 94.2% | 80.9% | 95.2% | 98.7% | 96.6% |
| PPV | 100.0% | 58.9% | 62.9% | 62.5% | 79.5% | 20.9% | 76.7% | 71.3% | 66.0% |
Note:— MTT with a threshold of 6.4 s was the most accurate parameter for the diagnosis of angiographic vasospasm, with especially a very high negative predictive value of 98.7%. FV indicates flow velocity; EICA, extracranial to intracranial; rCBV, relative cerebral blood volume; rCBF, relative cerebral blood flow; MTT, mean transit time; TTP, time-to-peak; TP, true- positives; FP, false-positives; FN, false-negatives; TP, true-positives; NPV, negative predictive value; PPV, positive predictive value.