• Computed Thomography
• Interstitial Lung DIseases
• Multidisciplinary Group
• Quantitative Analysis

Introduction
The gold standard for the diagnosis of Interstitial Lung Diseases (ILDs) is represented by the multidisciplinary group (MDG). CALIPER-based CT analysis quantifies and characterizes reproducibly radiological ILD features elaborating the glyph, iconic summary of ILD CT features extent and localization, able to optimize real-life MDG diagnosis.

Patients and methods
We retrospectively selected 240 ILD patients discussed by our MDG with suitable CTs for CALIPER analysis. Resulting glyphs were analyzed by an expert thoracic radiologist, blind to clinical-functional-imaging data, and clustered as confident/probable/indeterminate for Usual Interstitial Pneumonia (UIP) or as alternative diagnosis and consequently compared with MDG diagnosis. For cases labelled as alternative diagnosis, a specific glyph-based hypothesis of diagnosis was made.

Results
From the clustering over-mentioned, 110/240 cases (46%) glyph-based diagnosis resulted concordant with the MDG diagnosis. For 51/130 discordant cases, the radiologist performed a diagnosis of a probable UIP pattern versus a MDG diagnosis of confident UIP.
When a hybrid confident-probable UIP cluster was created, a concordance between glyph-based and MDG diagnosis was found in 161/240 cases (67%); radiologist’s grade of confidence in the interpretation of the glyph affects significantly the agreement while the use of different CT kernels do not affect the inter-rater agreement.
For 46/59 cases (78%) of concordant alternative diagnosis, a specific glyph-based diagnosis was correctly performed by the expert thoracic.

Discussion
CALIPER-derived glyphs represent a fast, easy and comprehensive representation of ILD radiological features extent and localization that could optimize MDG diagnosis and improve the consistency of the radiologist evaluation of imaging data. Further prospective studies would be helpful to corroborate these promising results.