Objective To analyze the imaging features of pulmonary artery sarcoma(PAS)on CT and MRI.Methods The clini-cal features,CT and MRI findings of 21 patients with pathologically confirmed PAS were analyzed retrospectively.Results All PAS lesions involved the central pulmonary artery,of which 15 cases involved the main pulmonary artery and bilateral pulmonary artery trunks,4 cases involved the main pulmonary artery and right pulmonary artery trunk,1 case involved the main pulmonary artery and left pulmonary artery trunk,and 1 case involved the right pulmonary artery trunk.Five cases involved the pulmonary artery valve and right ventricular outflow tract as well.Nineteen cases of PAS showed complete filling defects in the central pulmonary artery,and the other 2 cases presented with nodular or lobulated filling defects attached to the pulmonary artery wall.The proximal margin of 19 PAS lesions was bulging or lobulated,and the distal pulmonary artery of 9 PAS lesions showed aneurysm-like dilatation.On MRI,all 13 cases of PAS were hyperintense on fat-suppressed T2WI,of which 11 cases were hyperintense on diffusion weighted imaging(DWI),and all lesions demonstrated significantly heterogeneous enhancement or delayed enhancement.Conclusion On computed tomography pul-monary angiography(CTPA),filling defects which grow expansively in the central pulmonary artery,and which have proximal bul-ging shape or distal aneurysm-like dilatation are highly suggestive of PAS.On contrast-enhanced MRI,the significantly heterogene-ous enhancement mass in the central pulmonary artery should be highly suspected of PAS.