Clinical utility of diffusion lung carbon monoxide (DLCO) test in the follow-up of patients with organizing pneumonia

BACKGROUND: Chest high-resolution computed tomography (HRCT) plays a key role in the diagnosis and follow-up of patients with organizing pneumonia (OP). However, its repeated use is limited by high cost and radiation exposure. The aim of the study was to evaluate the utility of diffusion lung carbon monoxide (DLCO) test in monitoring OP response to oral corticosteroid (OCS) therapy and in relation to HRCT modifications.METHODS: It was a retrospective study. Among 40 OP patients, 20 had complete pulmonary function test and HRCT at baseline (T0) and after 3 months (T3) of OCS therapy and 16 after 6 months (T6). HRCT response to OCS was defined “complete” or “partial” in absence or persistence of any OP radiological findings, respectively.RESULTS: In comparison with T0, at T3 both DLCO and forced vital capacity (FVC), percentage (%) and absolute values, significantly increased (P