Nucs Chest

From WikiRad

[edit] PIOPED

Table 1. Modified PIOPED Criteria for Scan Interpretation

HIGH PROBABILITY

>2 large (>75% of a segment) segmental perfusion defects without corresponding ventilation or roentgenographic abnormalities or substantially larger than either matching ventilation or chest roentgenogram abnormalities

>2 moderate segmental (>25% and <75% of a segment) perfusion defects without matching ventilation or chest roentgenogram abnormalities and 1 large mismatched segmental defect

>4 moderate segmental perfusion defects without ventilation or chest roentgenogram abnormalities

INTERMEDIATE PROBABILITY (Indeterminate)

Single moderate mismatched segmental perfusion defect with normal chest roentgenogram *

Not falling into normal/very low, low, or high probability categories

LOW PROBABILITY

Any perfusion defect with a substantially larger chest roentgenogram abnormality

Large or moderate segmental perfusion defects involving no more than 50% of the combined lung fields with matching ventilation defects either equal to or larger in size, and chest roentgenogram either normal or with abnormalities substantially larger than perfusion defects

Any number of small segmental perfusion defects with a normal chest roentgenogram

NORMAL/VERY LOW PROBABILITY

No perfusion defects present **

Perfusion outlines exactly the same as the shape of the lungs on the chest roentgenogram (hilar and aortic impressions may be seen, chest roentgenogram and/or ventilation study may be abnormal) **

Non-segmental perfusion defects, (e.g., very small effusion causing blunting of the costophrenic angle; cardiomegaly; enlarged aorta, hila, or mediastinum; elevated diaphragm).

• Note that a single unmatched moderate perfusion abnormality was moved from the low category to the intermediate category in the modified PIOPED criteria.
• * Studies without perfusion defects are usually interpreted as normal perfusion rather than being placed into a very low probability category.