Aims

The clinical course of sarcoidosis is highly variable. Time and technology have eroded the usefulness of CXR to phenotype prognosis. Nearly all sarcoidosis patients will have had at least one CT prior to diagnosis. We aim to interrogate the usefulness of Lung Texture Analysis (Imbio^TM) to phenotype and provide prognostic information at the point of diagnosis.

Methods

Clinical data from 39 patients was recorded retrospectively including mode of presentation, Scadding CXR stage, markers of disease activity and pulmonary function tests at time of CT evaluation. All patients had minimum 2 year follow up data. LTA reported percentage Hyperlucency, Ground Glass Opacity (GGO), Reticulation, Honeycomb change and Pulmonary Vascular Volume. These were correlated to measures of disease activity including pulmonary function tests, trends, and need for treatment.

Results

LTA identified 4 distinct groups: dominant Hyperlucency, GGO, or Reticulation and minimal disease burden. There were no significant correlations between percentage of GGO and CRP (r 0.114), Peripheral Lymphocyte count (r 0.138), or uDLCO (r -0.159). There were stronger correlations with percentage hyperluceny and degree of airflow limitation (FEV1/FVC ratio and FEF 25-75%) r -0.496 and -0.364. Median follow up with physiology was 3.8 yrs. The hyperlucent grouping had the largest improvement in FVC at 2 years and were less likely to require oral steroids (OR 0.107 p 0.038).

Conclusions

Lung texture analysis supplements physician assessment of disease activity and burden not easily quantified by visual inspection of CT results. This pilot data provides intriguing insights into new CT disease phenotypes which may improve accurate diagnosis of disease burden and aid prognostication.