Abstract:

Objective: To investigate the imaging characteristics of pulmonary artery-bronchial artery dual-phase computed tomography angiography (CTA) in patients with pulmonary tuberculosis pseudo pulmonary embolism (PE) under the influence of bronchial-pulmonary shunt (BPS), in order to improve the diagnosis of pseudo-PE. Methods: A retrospective study was conducted on clinical data of 51 patients with pulmonary tuberculosis and pseudo-PE diagnosed and treated at Anhui Chest Hospital from August 2017 to January 2025. Fifty-one patients with pulmonary tuberculosis and true PE during the same period were selected as controls. The imaging features of dual-phase CTA in these two groups were compared and analyzed. Post-processing techniques including volume rendering (VR) and maximum intensity projection (MIP) were used to evaluate the status, quantity, and distribution of abnormal pulmonary artery filling on dualphase CTA in pseudoPE patients, and to observe the associated dilation and twisting of bronchial arteries. Results: The detection rate of hemoptysis in the pseudo-PE group was 47.1% (24/51), significantly higher than that in the true PE group (15.7%, 8/51; χ²=11.657, P=0.001). In the pseudo-PE group, the detection rates of destroyed lung and lobar/segmental atrophy in intrapulmonary lesions on CT were 47.1% (24/51) and 33.3% (17/51), respectively, significantly higher than those in the true PE group (15.7% (8/51) and 11.8% (6/51), respectively; χ²=11.657, P=0.001; χ²=6.793, P=0.009). In the pseudo-PE group, 55 pulmonary arteries at the lobar/segmental level or above exhibited abnormal filling on pulmonary arterial-phase CTA, and all showed delayed contrast agent filling on bronchial arterial-phase CTA. In the true PE group, 95 pulmonary arteries at the lobar/segmental level or above showed filling defects on pulmonary arterial-phase CTA, with no contrast opacification observed on bronchial arterial-phase CTA. The median CT values of abnormal pulmonary arteries on dualphase CTA in the pseudo-PE group were 178.00 (94.00, 250.00) HU and 412.00 (337.00, 462.00) HU, respectively, which were significantly higher than those in the true PE group (57.00 (48.00, 69.00) HU and 59.00 (50.00, 70.00) HU, respectively; Z=―9.330, P<0.001; Z=―10.192, P<0.001). Among the 55 pseudo-PE pulmonary arteries on pulmonary arterial phase CTA, 46 (83.6%, 46/55) showed filling defects and 9 (16.4%, 9/55) showed poor filling. Meanwhile, 69 associated tortuous and dilated bronchial arteries were detected on bronchial arterial-phase CTA, indicating pseudo-PE secondary to bronchial-pulmonary shunts (BPS). The pseudo-PE lesions involved 42 (76.4%, 42/55) upper lobe pulmonary arteries, 4 (7.3%, 4/55) right pulmonary arteries, 6 (10.9%, 6/55) left pulmonary arteries, and 3 (5.4%, 3/55) left lower lobe pulmonary arteries. Conclusion: In patients with pulmonary tuberculosis and BPS, pseudo-PE exhibits certain characteristics on pulmonary artery-bronchial artery dual-phase CTA. Effectively identifying its imaging features can provide assistance for early clinical diagnosis and treatment.

Key words: Bronchial-pulmonary shunts, Pulmonary embolism, Tuberculosis, pulmonary, Pulmonary artery, Angiography