HIGH-RESOLUTION CT AND PULMONARY-FUNCTION TESTS IN COLLAGEN VASCULAR-DISEASE - COMPARISON WITH IDIOPATHIC PULMONARY FIBROSIS

To estimate whether the lung abnormalities seen in collagen vascular d iseases (CVD) were similar or distinct to those seen in idiopathic pul monary fibrosis (IPF), and to ascertain whether the extent of the abno rmalities on high-resolution CT (HRCT) correlated with pulmonary funct ion, we reviewed HRCT findings and pulmonary function test results of 64 patients with either CVD (n = 55) or IPF (n = 9). Response to corti costeroid treatment was also evaluated in 20 of the 64. High incidence of honeycomb lesion was observed in IPF (9/9, 100%) and in progressiv e systemic sclerosis (PSS) (11/14, 79%). CVD, except for PSS, had a lo w incidence of honeycomb lesion (27%). On the other hand, incidence of ground-glass shadow in CVD (47/55, 85%) was the same as that in IPF ( 8/9, 89%). Diffusing capacity significantly correlated with the extent of all parenchymal abnormalities in all CVD and IPF, with honeycomb l esion in PSS, and with ground-glass shadow or air-space consolidation in CVD except for PSS (r < -0.7, P < 0.001). In all 15 cases in which corticosteroid therapy was effective, no honeycomb lesions were seen. Collagen vascular disease, except for PSS, had a different pattern of disease than IPF. The morphologic changes seen on HRCT correlated well with pulmonary function in CVD.