[The clinical and CT two-phase imaging features of bronchial-pulmonary arterial fistula].

OBJECTIVE

To study the clinical features of bronchial-pulmonary arterial fistula, and to analyze its imaging features.

METHODS

In continuous five months, 502 patients for pulmonary angiography were analyzed by pulmonary/aortic arterial two-phase scanning. The 128-slice MSCT (Siemens Definition AS 128) was used with the following parameters: the speed of 0.5 s/weeks, the collimator width of 64 × 0.6 mm, the pitch of 0.9, the tube voltage of 120 kV, the contrast agent of 300 mg/ml (1.2 ml/kg) , and the flow rate of 4.3 ml/s. Automatic trigger technology was used, while the threshold of the main pulmonary artery trunk was set to 80 HU. After 4 s delay, the pulmonary-arterial phase was scanned for 3-5 s. Then, the aortic-arterial phase was taken after 12 s. Finally, the clinical features and CTA two-phase images were analyzed by two radiologists, respectively. The diagnozied criteria of CTA images for bronchial-pulmonary arterial fistula were as following.In pulmonary/aortic arterial two-phase scanning, pulmonary artery or aortic artery could be displayed, respectively. The filling defect of fistula's pulmonary artery was observed in pulmonary arterial phase. However, the filling defect of fistula's pulmonary artery had significant filling in aortic arterial phase, with the similar density intensity of aortic artery.In addition, the thicken bronchial artery were observed in the fistula area.

CLINICAL FEATURES

In all 502 patients, 65 positive cases of the bronchial-pulmonary arterial fistula included 37 male cases and 28 female cases with ages from 45 to 83 years (69 ± 11). The clinical symptoms included hemoptysis (32%), anhelation (69%), hypoxia (66%), the raise of D2 dimer (70%), and pulmonary hypertension (64%). CTA two-phase images features: In the pulmonary-arterial phase, the intensity difference of pulmonary/aortic was [322 ± 122 (100-751)] HU. The local filling defect in the proximal pulmonary artery (12%) and the filling defect in the whole pulmonary artery (88%) were observed in 65 positive cases.In the aortic-arterial phase, the intensity difference of pulmonary/aortic was [251 ± 89 (85-428)] HU. The local enhancement in the proximal pulmonary artery (24%) and the enhancement in the whole pulmonary artery (76%) were observed in 58 positive cases. The visible thicken bronchial artery were observed in the fistula area of all cases.In 65 cases of bronchial-pulmonary arterial fistula, the fistula lesions contained 56 cases of lung lesions (including 35 cases of honeycomb lung, 16 cases of atelectasis, and 3 cases of chronic mass-like pneumonia) and 9 cases of vascular lesions (including 4 cases of chronic pulmonary artery embolism, 3 cases of congenital vascular malformation, 1 case of pulmonary arthritis, and 1 case of pulmonary artery aneurysm). 437 cases of non bronchial-pulmonary arterial fistula had 4 cases of of vascular lesions and 76 cases of lung lesions. There were significant statistic difference between the fistula and vascular lesions or lung lesions (the value of χ(2): 37.51 or 165.11, all values of P < 0.001).

CONCLUSION

The disease of bronchial-pulmonary arterial fistula usually occurred in the chronic pneumonia and the pulmonary vascular lesions. The CT pulmonary/aortic arterial two-phase scanning could detect the homodynamic changes to diagnosis this disease correctly. The pulmonary embolism need be differentiated.