Background Quantitative chest CT (QCT) is a promising procedure to assess the extent and severity of interstitial lung disease (ILD) in systemic sclerosis (SSc) patients. OsiriX and its 64-bit version, Horos, are two free open source software that make it possible to put to use a CT post-processing procedure that is definitely operator independent.

Objectives The main aim of this study is to investigate the feasibility of the operator independent method based on OsiriX/Horos as described by Ariani et al. [1] and hereafter abbreviated as ARIANI.

Methods To explore the feasibility, we address the following areas of focus: a) Demand (“Can ARIANI fill a gap in the field of ILD-SSc studies?”); b) Implementation (“Can ARIANI improve the current way to evaluate ILD-SSc?”); c) Acceptability (“Can ARIANI be used by a newbie after a one-hour training?”); d) Practicality (“How long does ARIANI take to give the QCT of a patient's ILD-SSc?”); e) Dissemination (“Does ARIANI require special equipment? Is it expensive and/or barely available?”). All the answers were extracted from the most current literature (only Pubmed and Academia.edu indexed papers or abstracts about ARIANI were reviewed) and from our own practice-based experience.

Results We selected four papers and five abstracts. Also taking into account our four year experience in performing QCT with ARIANI, we answered to all focus areas chosen. In summary, ARIANI can be extremely useful because the current ways to assess ILD-SSc are not completely satisfying for their inter/intra-observer variability (Demand). Conversely, an operator independent algorithm can represent a starting point to develop a new standard evaluation (Implementation). All the rheumatologists (two) and medical students (two) that were trained, learned how to successfully complete the QCT assessment without requiring any other explanation even after three years (Acceptability). ARIANI requires 1.8 min (range from 0.5 to 3.2 min); this time interval is mainly influenced by the computer configuration (Practicality). The use of Apple (R) computers (which are quite widespread hardware) is mandatory because of the OsiriX/Horos software architecture running only on MacOs X. ARIANI performance is virtually possible on every Mac now available for sale and on the majority of those built in the last seven years (Dissemination).

Conclusions Taking into account the previous close examination, the use of OsiriX/Horos with ARIANI appears potentially useful in ILS-SSc assessment and limited only in those few centers in which there is no availability of the required equipment (i.e. computed tomographies and Mac computers). Thus, ARIANI feasibility seems to be good and ready for a world-wide spread.

1. Ariani A, et al. Utility of an open-source DICOM viewer software (OsiriX) to assess pulmonary fibrosis in systemic sclerosis: preliminary results. Rheumatol Int.2014 Apr;34(4):511–6. doi: 10.1007/s00296-013-2845–6.

Disclosure of Interest None declared