Summary of Strengths and Limitations of CTPA, V/Q SPECT, and V/Q SPECT/CT
| Parameter | CTPA | V/Q SPECT | V/Q SPECT/CT |
| Sensitivity | Moderate-high | High | High |
| Specificity | Very high | High | Very high |
| Accuracy with abnormal radiograph finding | Unaffected | Sometimes affected | Sometimes affected |
| Ability to provide other diagnoses | Frequent | Rare | Frequent |
| Incidental findings requiring follow-up | Frequent | Rare | Less frequent |
| Radiation dose | High | Low | Low-moderate |
| Possible allergic reaction | Yes | No | No |
| Risk of contrast nephropathy | Yes | No | No |
| Technical failure rate | Higher | Rare | Rare |
| Availability (especially outside routine hours) | High | Usually lower | Usually lower |
| Accuracy in pregnancy | Lower | High | High |
| Accuracy in chronic PE | Lower | High | High |
| Performance in obstructive lung disease | Unaffected | May be affected | May be affected |
| Role and accuracy in follow-up | Limited | Very good | Very good |