Background: In central airway stenosis, stenting leads to an increase in bronchial patency and to the active distribution of ventilation. However, an improvement in blood flow and gas exchange has not yet been understood. The purpose of this study is to evaluate the distribution of pulmonary blood flow using computed tomography (CT) and perfusion scintigraphy.Methods: We assessed lung perfusion in 8 patients with bronchial stenosis. CT and perfusion scintigraphy were performed before and after interventional bronchoscopy. We measured the cross-sectional area (CSA) of less than 5 mm2 (CSA<5), 10 mm2 (CSA<10), and 100 mm2 (CSA<100) by computed tomography. The scintigraphic lung image was divided into the right and left lung. The distribution of lung perfusion was calculated to express the mean counts for the respective lungs as a percentage of the total counts in both lungs.Results: In patients with bronchial stenosis, perfusion was reduced at the obstructed area. After intervention, two different findings were obtained depending on the duration of obstruction. When airway obstruction occurred for less than 1 month, perfusion immediately improved due to better ventilation. In patients with long-term lung collapse, perfusion was still severely reduced at the obstructed area. Three month later, CT and perfusion scintigraphy showed an improvement in blood flow. CSA<5, CSA<10 and CSA<100 were significantly correlated with the distribution of lung perfusion (r=-0.67, P<0.01; r=-0.71, P<0.01; r=-0.66, P<0.01, respectively).Conclusions:Interventional bronchoscopy improved blood flow and gas exchange. CT and perfusion scintigraphy were useful in the assessment of regional blood flow.