Application of lung V/Q SPECT imaging in fibrosing mediastinitis

Objective To investigate the value of pulmonary ventilation/perfusion (V/Q) SPECT imaging in fibrosing mediastinitis (FM). Methods From January 2015 to July 2018, 14 FM patients (6 males, 8 females, average age 74 years) who underwent V/Q SPECT imaging in China-Japan Friendship Hospital were retrospectively studied. The data of V/Q SPECT imaging were analyzed and the defect extent was classified as mild ( 50%) according to the percentage of pulmonary perfusion and ventilation defect in total lung volume (%). χ2 test was used to analyze the incidence rates of the impaired blood perfusion of each lung lobe. Results According to the results of Q SPECT imaging, all 14 patients had impaired blood perfusion in the superior lobe of left lung, and the number of patients with/without impaired blood perfusion in the inferior lobe of left lung, superior lobe of right lung, middle lobe of right lung, inferior lobe of right lung were 11/3, 14/0, 13/1, 12/2, respectively. The incidence rates of impaired blood perfusion in different lobes were not significantly different (χ2=6.198, P=0.185). The range of lung perfusion defect was mild in 1, moderate in 7 and severe in 6 patients. The incidence rates of impaired blood ventilation in different lobes were not significantly different (χ2=1.587, P=0.811). The range of lung ventilation defeat was mild in 11, moderate in 2 and severe in 1 patients. The defect extent of lung segments and subsegments in Q SPECT imaging and V SPECT imaging were 119 and 41, respectively (χ2=28.42, P<0.05). There was more defect in Q SPECT imaging, but both methods showed segmental or subsegmental distribution. Conclusions The defect of V/Q SPECT imaging in FM patients is segmental in distribution, and more is observed in Q SPECT imaging. Pulmonary V/Q SPECT imaging can evaluate the defect range and extent of pulmonary perfusion and ventilation in FM patients. Key words: Mediastinitis; Fibrosis; Radionuclide imaging; Technetium Tc 99m aggregated albumin; Sodium pertechnetate Tc 99m