Modified PIOPED II and PISAPED Scintigraphic Criteria
| Criteria | ||
|---|---|---|
| Finding | Modified PIOPED II | PISAPED |
| PE present | High probability (2 or more segments of perfusion–chest radiograph mismatch) | One or more wedge-shaped perfusion defects |
| PE absent | Normal perfusion | Normal perfusion |
| Very low probability | ||
| Nonsegmental lesion, for example, prominent hilum, cardiomegaly, elevated diaphragm, linear atelectasis, or costophrenic angle effusion with no other perfusion defect in either lung radiographic lesion | Near normal | |
| Perfusion defect smaller than radiographic lesion | Contour defect caused by enlarged heart, mediastinum, or diaphragm | |
| 1–3 small segmental defects | Perfusion defect, not wedge-shaped | |
| Solitary chest radiograph–perfusion matched defect in mid or upper lung zone confined to single segment | ||
| Stripe sign around perfusion defect (best tangential view) | ||
| Pleural effusion in at least one third of pleural cavity, with no other perfusion defect in either lung | ||
| Not diagnostic | All other findings | Cannot classify as PE-positive or PE-negative |