The purpose of this study is to assess efficiency and safety of cryobiopsy compared to video-assisted thoracoscopic lung biopsy (VATS) in diagnosis of interstitial lung diseases (ILD). To that end, this non-interventional study prospectively collects data from patients undergoing routine diagnosis of ILD. In some of those patients less invasive diagnostic approaches do not yield a definitive diagnosis. Thus, they will ultimately be subjected to VATS if this procedure is reasonable. The information gained by this study will help to assess the significance of cryobiopsy in contrast to VATS in this particular disease group.