Utility of an open-source DICOM viewer software (OsiriX) to assess pulmonary fibrosis in systemic sclerosis: preliminary results.

To investigate the utility of an open-source Digital Imaging and Communication in Medicine viewer software-OsiriX-to assess pulmonary fibrosis (PF) in patients with systemic sclerosis (SSc). Chest high-resolution computed tomography (HRCT) examinations obtained from 10 patients with diagnosis of SSc were analysed by two radiologists adopting a standard semiquantitative scoring for PF. Pulmonary involvement was evaluated in three sections (superior, middle and inferior). For the assessment of the extension of PF, the adopted semiquantitative HRCT score ranged from 0 to 3 (0 = absence of PF; 1 = 1-20 % of lung section involvement; 2 = 21-40 % of lung section involvement; 3 = 41-100 % of lung section involvement). Further, a quantitative assessment (i.e. parameters of distribution of lung attenuation such as kurtosis and mean lung attenuation) of PF was independently performed on the same sections by a rheumatologist, independently and blinded to radiologists' scoring, using OsiriX. The results obtained were compared with those of HRCT semiquantitative analysis. Intra-reader reliability of HRCT findings and feasibility of OsiriX quantitative segmentation was recorded. A significant association between the median values of kurtosis by both the quantitative OsiriX assessment and the HRCT semiquantitative analysis was found (p < 0.0001). Moreover, kurtosis correlated significantly with the mean lung attenuation (Spearman's rho = 0.885; p = 0.0001). An excellent intra-reader reliability of HRCT findings among both readers was obtained. A significant difference between the mean time spent on the OsiriX quantitative analysis (mean 1.85 ± SD 1.3 min) and the mean time spent by the radiologist for the HRCT semiquantitative assessment (mean 8.5 ± SD 4.5 min, p < 0.00001) was noted. The study provides the new working hypothesis that OsiriX may be a useful and feasible tool to achieve a quantitative evaluation of PF in SSc patients.