Diagnostic Accuracy of offline Lung Perfusion SPECT/CT in Diagnosis of Pulmonary Embolism

Abstract

In this study, we evaluate the diagnostic value of alternative methods and SPECT perfusion lung scan combined on lung CT scan (Offline Q-SPECT / CT that is a non-invasive method) in comparison with the lung CT angiography, especially for patients with special conditions, including pregnant women, elder people, and even with low awareness and low cooperation. Materials and methods: In this retrospective study, 50 patients with a medical history of pulmonary thromboembolism within the past week underwent CT angiography, perforation scanning (by planar and spect) and lung ventilation (by planar method) done for all of them, entered to our study. Using E-soft software, Patients spect perfusion scan images were combined with non Contrast CT scan images. Decreased segmental pulmonary perfusion without a parenchymal lesion or Consolidations was considered in favor of pulmonary embolism. The sensitivity, specificity, and diagnostic accuracy of methods Calculated after Comaparing with the standard method CT pulmonary angiography. Results: In the follow-up of 50 patients (24 males and 26 females) with an average age of 18 ± 56 years with complaints of shortness of breath and the possibility of pulmonary embolism (based on the findings of the standard method that was CT pulmonary angiography), for 19 patients (38%) A final pulmonary embolism was diagnosed and a pulmonary embolism was rejected for 31 patients (62%). Based on the findings of lung perfusion and ventilation scan, according to PISAPED criteria, the probability of pulmonary embolism was reported for 20 patients low (40%), 13 patients moderate (26%) and 17 patients (34%) high. The sensitivity, specificity and accuracy of this method were 100%, 65% and 75% respectively. In the Offline Q-SPECT / CT method reported negative pulmonary embolism diagnosis for 28 patients (56%) and positive pulmonary embolism diagnosis for 22 patients (44%). The sensitivity, specificity and accuracy of this method were 100%, 90% and 94%, respectively.