PE: • V/P mismatch of at least one segment or two subsegments in keeping with the pulmonary vascular anatomy (wedge-shaped defects with the base projecting to the lung periphery).

No PE: • Normal perfusion pattern in keeping with the anatomic boundaries of the lungs. • Matched or reversed-mismatched V/P defects of any size, shape or number in the absence of mismatch. • Mismatch that does not follow a lobar, segmental or subsegmental pattern.

Nondiagnostic for PE: • Widespread V/P abnormalities not typical of specific diseases.