[Evaluation of pulmonary perfusion in a patient with agenesis of the left pulmonary artery: usefulness of radionuclide angiography].

We reported a case with agenesis of the left pulmonary artery, in which radionuclide angiography with 99mTc-HSA and time activity curve (TAC) were useful in evaluating pulmonary perfusion in the effected lung. The case involved a 32-year-old male, who underwent nuclear medicine examination including 99mTc-MAA scanning, 81mKr scanning and 99mTc-HSA angiography. 99mTc-MAA and 81mKr scanning showed the perfusion defect and decreased ventilation in the effected lung, respectively. On the other hand, the delayed images of 99mTc-HSA angiography showed the existence of perfusion in the effected lung, although the early images showed the perfusion defect in the same lung. The TAC whose region of interest was placed on the hilus showed that the effected lung was gradually filled with the blood flow through the collateral pathways. In addition, the ratio of area under the TAC on the contralateral lung versus the effected lung was 4.6, while the volume ratio of the contralateral lung versus the effected lung obtained from X-ray CT images was 2.7. Therefore, it was suggested that the perfusion per volume in the effected lung was decreased, compared with that in the contralateral lung. It was concluded that 99mTc-HSA angiography was useful in evaluating the perfusion of the effected lung in a patient with agenesis of the left pulmonary artery.