Purpose: To investigate the success of different quantitative lung assessment (QLA) methods on high-resolution CT (HRCT) to assess the severity of Sjogren's syndrome (SjS) related interstitial lung disease (ILD).
Method: Consecutive SjS patients who underwent both thin-section HRCT and pulmonary function tests (PFTs) were investigated. The QLA was obtained using two different DICOM (digital imaging and communications in medicine) viewer with three different methods and lung histogram values. HRCT images were semiquantitatively (SQLA) evaluated in consensus by two radiologists using the Goh score and, two groups were established: limited (< 20%), extensive (> 20%) ILD. Spearman's correlation test was used to assess the correlation between variables. ROC curve analysis was performed to determine the ability of QLA methods to distinguish ILD groups.
Results: Thirty-four patients were included, and SQLA revealed limited ILD in 22 patients (64.7%). PFT values were significantly lower in the extensive ILD group. The QLA scores showed a significant difference between limited and extensive ILD groups, and all QLA indices showed a significant correlation with SQLA and PFTs. ROC analysis showed that mean lung attenuation and Method-1 (ILD: voxels between -200 and -700 HU) were the best to distinguish the ILD severity by 0.93 (CI 95 0.83 -1%) and 0.84 (CI 95 0.71-0.97%), respectively.
Conclusion: The QLA methods are a promising alternative to the Goh score in the objective evaluation of SjS-related ILD. The QLA methods are capable of distinguishing extensive (which is responsible for poor prognosis in SjS patients) from limited ILD.
Keywords: Computed tomography; Connective tissue diseases; Image analysis; Interstitial; Lung diseases.
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