Aim: To evaluate the utility of ventilation scintigraphy and chest X-ray in the assessment of the lung perfusion scintigraphy and to evaluate the utility of clinical findings in the diagnosis of pulmonary thromboembolism.
Material and methods: A total of 100 patients who underwent a ventilation-perfusion scintigraphy due to suspicion of pulmonary thromboembolism were studied retrospectively. Three observers evaluated scintigraphic findings, blind to the other data on the patient. They consecutively added ventilation scintigraphy and chest X-ray to the perfusion study, making a consensus interpretation. Clinical findings were also evaluated. Sensitivity, specificity, positive and negative predictive values and global value test were calculated, using the final diagnosis presented by the patients on discharge as the gold standard. The Kappa statistics index was used to evaluate the degree of agreement between the three observers and the correlation between clinical and scintigraphic findings.
Results: On adding the information of the ventilation to the perfusion study, specificity increased and sensitivity decreased. Kappa statistics between observers also increased. The chest X-ray did not significantly change the scintigraphic results. Little correlation was found between the clinical and scintigraphic findings, this association being greater in low probability studies.
Conclusions: We think that the performance of the ventilation study has great value in the interpretation of perfusion studies. The chest X-rays did not significantly change the scintigraphic results. Clinical data are important to establish pre-test probability and in their integration with the scintigraphy information.