The conclusions drawn from ventilation/perfusion single-photon emission computed tomography compared with lung perfusion single-photon emission computed tomography and chest radiography in patients with suspected pulmonary thromboembolism.

PURPOSE: There are conflicting results from studies on whether ventilation scintigraphy can be safely omitted or replaced by chest radiography. These studies were based on planar ventilation/perfusion (V/Q) scintigraphy. We evaluated the value of the ventilation single-photon emission computed tomography (SPECT) on the final conclusion drawn from a V/Q SPECT and the possible role of the chest radiography as a surrogate for the ventilation SPECT.

PATIENTS AND METHODS: Raw data of V/Q SPECT images and chest radiography acquired within 48 h over an 18-month period were retrieved, reprocessed and reviewed in batches. The ventilation SPECT, perfusion SPECT and chest radiography were reviewed separately and in combination. Data on the presence and nature of defects and chest radiography abnormalities were recorded. The V/Q SPECT images were interpreted using the criteria in the EANM guideline and the perfusion SPECT and chest radiography images were interpreted using the PISAPED criteria. Agreement between the diagnosis on the V/Q SPECT review and the perfusion SPECT and chest radiography review was analysed.

RESULTS: Overall, 21.1% of the patients were classified as 'PE present' on the V/Q SPECT review, whereas 48.9% were classified as 'PE present' on the perfusion SPECT and chest radiography review. Only 5.4% of defects observed on ventilation SPECT had matched chest radiography lung field opacity.

CONCLUSION: Our study showed that the omission of a ventilation SPECT led to a high rate of false-positive diagnoses and that the ventilation scan cannot be replaced by a chest radiography.