The direct signs of helical CT and pulmonary angiograph included partial filling defect, mural filling defect, central filling defect or so-called railway-track sign, and total occlusion.

• 肺动脉栓塞的影像学直接征象包括部分性充盈缺损、附壁性充盈缺损、中心性充盈缺损（即“轨道征”）、完全阻塞，间接征象包括主肺动脉增宽、局限性肺纹理稀疏、肺梗死和胸腔积液。