Objective  To explore the added value of SPECT/CT fusion imaging in the etiological diagnosis of patients with unilateral absence in planar pulmonary perfusion imaging.

Methods  A retrospective analysis was performed on 29 patients (14 males and 15 females, aged 59.8±11.1 years) with unilateral absence who received pulmonary perfusion plane imaging from January 2019 to July 2022 in Gansu Provincial Hospital. All patients underwent SPECT/CT fusion imaging, and the final diagnosis was confirmed through pulmonary artery CT angiography, pulmonary angiography, and clinical data. In accordance with the etiology, the patients were divided into pulmonary vascular disease group and pulmonary disease group. The etiology of unilateral lung opacities in the two groups was analyzed through SPECT/CT fusion imaging. The laboratory test results of the two groups of patients were recorded and compared. Independent sample t-test or Mann-Whitney U test was used for intergroup comparison.

Results  The pulmonary vascular disease group consisted of 12 cases, including 7 cases (58.3%) of pulmonary vasculitis, 4 cases (33.3%) of fibrosing mediastinitis, and 1 case (8.3%) of congenital absence of right pulmonary artery. The pulmonary disease group had 17 cases, including 8 cases (47.1%) of pleural effusion, 3 cases (17.6%) of hilar tumor, 1 case (5.9%) of emphysema, 1 case (5.9%) of pulmonary bullae, 1 case (5.9%) of left atelectasis, 1 case (5.9%) of left thoracic collapse, 1 case (5.9%) of postoperative absence of left lung, and 1 case (5.9%) of organized pneumonia. No significant differences were found in the results of laboratory tests between the two groups (Z=−1.900 to −0.296, t=−1.313 to 0.917, all P>0.05) except blood oxygen partial pressure (t=−2.681, P<0.05).

Conclusion  SPECT/CT fusion imaging can provide more valuable information than planar imaging. It has added value in the etiological diagnosis of patients with unilateral absence in planar pulmonary perfusion imaging.