Table 3:
Readers' performance in evaluating PCT and C-arm CT imagesa
| Reader 1 | Reader 2 | Reader 3 | Mean | |
|---|---|---|---|---|
| TP readings of PCT | 75.0% | 70% | 75% | 73.3% |
| TP readings of C-arm CT | 83.3% | 83.3% | 86.7% | 84.4% |
| FP readings of PCT | 0% | 5% | 0% | 1.7% |
| FP readings of C-arm CT | 0% | 3.3% | 6.7% | 3.3% |
| FN readings of PCT | 25% | 25% | 25% | 25% |
| FN readings of C-arm CT | 16.7% | 13.3% | 6.7% | 12.2% |
a
Percentage of TP (infarct was correctly identified), FP (CBV abnormality identified in a location where there was no DWI abnormality), and FN (no abnormality identified in location where there was a DWI abnormality) readings are given for each reader individually and the mean of all 3 readers. C-arm CT readings demonstrate a better correlation with the criterion standard DWI. Most interesting, the rate of FP readings is very low. Please note the discrepancy of FN PCT and FN C-arm CT readings.