Bronchoscopic lung volume reduction (BLVR) has recently been introduced as a less invasive potential alternative to surgical lung volume reduction. BLVR attempts to achieve the effects of surgery, by placing bronchial prostheses using a fibreoptic bronchoscope to selectively occlude the airways supplying the most affected hyperinflated regions of the emphysematous lung, while permitting exhaled gas to escape. This attempts to achieve segmental or lobar volume reduction, simulating the effects of surgical LVR. Recent trials of BLVR using endobronchial one-way valves demonstrated significant improvements in lung function parameters, exercise capacity and quality of life in patients with end-stage emphysema. The treatment algorithm for valve implantations to achieve BLVR, however, varied considerably in these reports as well as clinical and functional response rates. Subset analysis of these studies revealed that particularly, but not exclusively, patients with radiological signs of lung volume reduction treated unilaterally showed significant clinical improvements, whereas most patients without signs of lung volume reduction did not experience these benefits. The present study investigates the response to BLVR based on a new treatment algorithm including lung function criteria and computed tomography of the thorax.