Table 4.
Intra- and interobserver variability in assessing swine coronary segments by OFDI and IVUS
| Intraobserver variability | Interobserver variability | |||
|---|---|---|---|---|
| Mean difference between 1st and 2nd time analysis | Coefficient of variation (%) | Mean difference between 1st and 2nd observer | Coefficient of variation (%) | |
| OFDI | ||||
| Mean LD (mm) | 0.02 ± 0.02 | 1.1 | 0.04 ± 0.02 | 0.9 |
| Minimum lumen area (mm2) | 0.06 ± 0.08 | 2.6 | 0.14 ± 0.06 | 2.0 |
| Lumen VI (mm3/mm) | 0.07 ± 0.09 | 2.4 | 0.12 ± 0.09 | 2.3 |
| Minimum stent area, tracing at LE (mm2) | −0.03 ± 0.06 | 1.4 | −0.04 ± 0.07 | 1.6 |
| Minimum stent area, tracing at HIP (mm2) | −0.05 ± 0.09 | 1.9 | 0.01 ± 0.07 | 1.4 |
| Stent VI, tracing at LE (mm3/mm) | −0.03 ± 0.04 | 0.9 | −0.09 ± 0.04 | 0.8 |
| Stent VI, tracing at HIP (mm3/mm) | −0.04 ± 0.04 | 0.8 | −0.03 ± 0.05 | 1.0 |
| Neointimal VI, tracing at LE (mm3/mm) | −0.05 ± 0.06 | 3.0 | −0.16 ± 0.05 | 2.4 |
| Neointimal VI, tracing at HIP (mm3/mm) | −0.07 ± 0.07 | 3.0 | −0.09 ± 0.07 | 3.5 |
| IVUS | ||||
| Mean LD (mm) | −0.02 ± 0.09 | 4.1 | 0.003 ± 0.11 | 5.4 |
| Minimum lumen area (mm2) | −0.10 ± 0.47 | 14.1 | 0.02 ± 0.53 | 16.3 |
| Lumen VI (mm3/mm) | −0.08 ± 0.26 | 7.2 | −0.002 ± 0.34 | 9.5 |
| Minimum stent area (mm2) | 0.01 ± 0.10 | 2.1 | 0.18 ± 0.16 | 3.4 |
| Stent VI (mm3/mm) | 0.00 ± 0.06 | 1.2 | 0.001 ± 0.03 | 0.6 |
| Neointimal VI (mm3/mm) | 0.12 ± 0.34 | 19.4 | 0.005 ± 0.42 | 22.9 |
Second observation by same investigator was performed at least 4 weeks later after 1st observation
HIP highest intensity points, IVUS intravascular ultrasound, LD lumen diameter, LE leading edge, OFDI optical frequency domain imaging, VI volume index