**3. Interpretation**

According to the new European guidelines, the holistic interpretation of lung SPECT is recommended (Bajc et al., 2009b). The clinician can only benefit from reports, which clearly express the presence or absence of PE. This goal was not achieved with previous probabilistic reporting methods according to PIOPED or modified PIOPED. Large V/P SPECT studies show that this is achievable if all patterns are considered, where these combine ventilation and perfusion. Conclusive reports were given in 97 to 99 % of studies.

Holistic interpretation of V/P SPECT should be based upon: a) Clinical pre-test probability and b) the application of criteria for interpreting V/P patterns to distinguish between patterns indicative of PE and other diseases.
