Purpose: Interstitial lung disease (ILD) related to systemic sclerosis (SSc) is assessed with pulmonary functional tests (PFTs) and semi-quantitative scores based on extent of ILD detectable on chest computed tomography (CT). CT quantitative indexes (QCTIs) are promising tools to assess extent of ILD. This study's aim is to evaluate the validity of QCTI compared with that of chest CT standard evaluation and PFTs. Moreover, QCTI differences between patients' subgroups according to prognostic stratifications were investigated.
Methods: ILD-SSc of patients from six rheumatological clinics was routinely assessed with chest CT and PFTs. Patients were clustered according to prognosis based on functional and/or radiological examinations. Finally, chest CTs were processed with OsiriX in order to obtain QCTI.
Results: Two hundred fifty-seven SSc patients were enrolled. QCTI correlation between extent of ILD and PFTs range from - 0.60 to 0.58 and from - 0.54 to 0.52, respectively. The majority of QCTI have a different distribution in patients' subgroups based on prognosis. Most of QCTI discriminate patients with an ILD severity leading to a poor prognosis.
Conclusions: QCTI assessment of ILD-SSc is comparable to the evaluation based on chest CT and/or PFTs. QCTI values corresponding to severe ILD were identified. QCTIs are excellent candidates for a new and more reliable SSc-ILD assessment.
Keywords: CT indexes; CT quantitative assessment; Interstitial lung disease; OsiriX; Systemic sclerosis.