Intrapulmonary shunt was measured by $^{99m}Tc$-MAA perfusion tung scan. The study was included 76 patients. Significant amount of intrapulmonary shunt was observed in the pulmonary disease patients and liver disease patients. The shunt amount was correlated well with $PaO_2$ and $AaDO_2$ level. Further study is needed to search the various factors affecting the amount of intrapulmonary shunt.