Abstract: Objective To evaluate the value of SPECT imaging in the diagnosis of pulmonary embolism(PE).Methods SPECT and planar pulmonary perfusion imagings were done in 519 patients with first episode of PE.The results were compared with those of spiral CT pulmonary arteriography(CTPA).Results Among the total 227 patients with planar pulmonary and SPECT imagings,the detection rates of PE was 89.4%(203) and 98.2%(223) respectively.There was significant difference between planar pulmonary and SPECT imaging in detection rate(P<0.01).Among the 221 patients with CTPA results,the abnormal segments detected by CPTA were 976,and by planar pulmonary imaging 796;the coincident rate was 81.6%.In the SPECT imagings,937 abnormal segments were detected,with a 96% coincident rate.Detection rate also differed significantly.Conclusion SPECT imaging improves the performance of diagnosis of PE significantly,it can take place of planar pulmonary imaging and become the routine in the diagnosis of PE.

Key words: pulmonary embolism, thromboembolism, radionuclide imaging, spiral CT, SPECT