Complex sentence: The diagnosis of DPB requires analysis of the lungs and bronchiolar tissues, either via a lung biopsy or, more preferably, a high resolution computed tomography (HRCT) scan of the lungs.
Split into simpler sentences: The diagnosis of DPB requires analysis of the lungs and bronchiolar tissues. Analysis of these tissues can require a lung biopsy, or the more preferred high resolution computed tomography (HRCT) scan of the lungs.