The efficiency of hybrid perfusion SPECT/CT imaging in the diagnostic strategy of pulmonary thromboembolism.

Abstract

Ventilation/perfusion single photon emission computed tomography (V/Q SPECT) is recommended as a reference radionuclide method in pulmonary thromboembolism (PTE) diagnosis. However, there is some logistic, economic, and infectious concern about the study's ventilation part. This study aimed to evaluate the effectiveness of hybrid perfusion SPECT with a low dose CT method in the diagnostic strategy of PTE. Two physicians reviewed 305 patients' data for this retrospective study. All patients had Q SPECT/CT data as initial imaging, and Ventilation SPECT was added to the selected patients' algorithm. The diagnostic performance and inter-observer agreement were determined for both Q SPECT and Q SPECT/CT methods. The final diagnosis was made by clinical decision with all tests and follow-up for at least 6-month. The majority (92%) of our study group were correctly diagnosed with the Q SPECT/CT method with excellent inter-observer agreements (κ=0.914). The sensitivity, specificity, and accuracy of methods were as follows; 92.2%, 76.3%, and 80.3% for Q SPECT; 96.1%, 94.5%, and 98.8% for Q SPECT/CT (P<0.001). The ventilation scan was applied to 29% (n=88) of the study group. It is prominent in 21/88 patients whose Q SPECT/CT result was non-diagnostic or discordant with clinical probability. Q SPECT/CT recommended as the initial radionuclide imaging in PTE diagnosis, with high diagnostic accuracy and inter-observer agreement. Ventilation scans can be optimized according to Q SPECT/CT results avoiding unnecessary irradiation and other potential adverse effects, including infectious risk in the current pandemic context.