Linear Dependency of Total-Lung Early and Delayed L/M Ratios, Washout Rate, and Extent of Perfusion Defects and Low-Attenuation Areas on A-aDO2 in PE Patients
| Parameter | Formula | R | P |
| Early L/M ratio | y = 34.147 – 8.569x | 0.406 | 0.0027 |
| Delayed L/M ratio | y = 32.204 – 7.51x | 0.363 | 0.029 |
| Washout rate | y = 22.042 – 1.18x | 0.833 | <0.0001 |
| Perfusion defects* | y = 11.265 + 459x | 0.333 | 0.0471 |
| Low-attenuation areas† | y = 20.345 + 031x | 0.024 | NS |
* Percentage of total-lung voxels with radioactivity < 10% of maximum on perfusion SPECT.
† Percentage of total-lung voxels with attenuation < −960 HU on CT.
NS = not statistically significant.