High-resolution computed tomography and scleroderma lung disease

High-resolution CT has now become an important part of the routine detection and evaluation of interstitial lung disease in SSc. CT now has a central role in the detection of interstitial disease, largely because other modalities have been unsatisfactory in this regard. Historically, CT has also been used to identify a high likelihood of reversible inflammatory disease in SSc, based upon studies in other diffuse lung diseases. However, accumulated evidence indicates that ground-glass attenuation on CT is not a reliable indicator of underlying alveolitis. Ground-glass attenuation on CT is common in SSc but reversible disease is found at surgical biopsy in a minority of cases, and is rare when ground glass is associated with reticular abnormalities or traction bronchiectasis. Furthermore, ground glass regresses inconsistently on serial CT evaluation, with or without treatment. CT is more useful in the staging of disease extent. Although formal CT scoring is not realistic in routine practice, rapid semi-quantitative estimation of disease extent on CT in combination with a forced vital capacity threshold has been used to stage disease as limited or extensive. The distinction between a higher and lower risk of progression of lung disease, made using this system, has important implications for both routine practice and the enrolment of higher risk patients in therapeutic studies.