Comparison of scintigraphic diagnostic criteria in suspected pulmonary embolism

Various criteria have been proposed for the interpretation of ventilation and perfusion (V/Q) scintigrams in diagnosing pulmonary thromboembolism. The Biello criteria, with modifications, have been a standard for years but they differ from the criteria currently being used in the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) trial. We carried out a retrospective study in an attempt to establish if one or the other set of criteria is better. Between February 1985 and September 1987, 38 patients had a V/Q scan for suspected pulmonary embolism and subsequently underwent pulmonary angiography. The V/Q scans were reviewed by two observers using the modified Biello and the PIOPED criteria. Receiver-operated characteristic curves were constructed separately for each set of criteria. Statistical analysis revealed that neither set of criteria was significantly better than the other, but the PIOPED criteria were felt to be better defined and easier to use. This may have implications for the practical application of the criteria.