To compare multislice spiral CT to digital subtract pulmonary angiography for the detection of subsegmental pulmonary emboli by using a cast of porcine pulmonary vessels as an independent gold standard.

• 以肺动脉血管铸型标本为金标准，比较多层螺旋CT肺动脉造影、数字减影X线肺动脉造影对亚段肺动脉栓塞的显示能力。