HRCT and scleroderma: semiquantitative evaluation of lung damage and functional abnormalities

This study sought to validate the Warrick score in the assessment of lung involvement in systemic sclerosis (SSc) and correlate the results with functional abnormalities. In addition, we propose the use of high resolution computed tomography (HRCT) indices of alveolitis and fibrosis to discriminate between different stages of the disease.

Thirty-one patients with SSc (16 with the diffuse form and 15 with the limited form) underwent functional and HRCT evaluations of the lung. The semiquantitative evaluation of radiological involvement, as proposed by Warrick, provides a score for each lesion based on the severity and the extent of the pulmonary damage. In addition to the total score, indices for alveolitis and fibrosis were created. The association between each score and functional abnormalities was tested.

The total Warrick score was 16+/-7.7 [mean+/-standard deviation (SD)]. The total score correlated inversely with total lung capacity (TLC) (percentage of predicted TLC) (r=-0.38; p=0.04), diffusion lung capacity for carbon monoxide (DLCO) (percentage of predicted DLCO) (r=-0.43; p=0.02) and with forced expiratory volume in 1 second (FEV1) (percentage of predicted FEV1) (r=-0.36; p=0.05). The alveolitis and fibrosis indices were 1.9+/-1.1 and 14.2+/-7.4, respectively. The alveolitis index correlated significantly with percentage of predicted DLCO (r=-0.46; p=0.01) but not with percentage of predicted TLC (r=-0.28; p=0.13). The fibrosis index correlated both with percentage of predicted DLCO (r=-0.38; p=0.04) and with percentage of predicted TLC (r=-0.35; p=0.05).

Our findings confirm the diagnostic role of HRCT in assessing the extent of lung damage in SSc. Furthermore, the two indices (alveolitis and fibrosis) provide new tools for evaluating the relationship between pulmonary involvement and systemic impairment in SSc.