[Idiopathic pulmonary fibrosis: correlation between helical CT findings and pulmonary function test results]

To determine the correlation between helical CT findings and pulmonary function test (PFT) results from patients with idiopathic pulmonary fibrosis(IPF).

Helical CT scan was performed in 32 cases with clinically and/or pathologically proved idiopathic pulmonary fibrosis. Pulmonary function test for each patient was performed within 5 days before or after CT scan. The correlation between CT findings and pulmonary function test results was assessed.

Pulmonary function test revealed characteristic restrictive ventilatory defect with reduction of total lung capacity, residual volume, vital capacity, and diffusing capacity of the lung for carbon monoxide. The patients with different severities of pulmonary function impairment had different CT features. 4 of 5 cases with slight impairment of the pulmonary function had the ground-glass opacity, 11 cases with moderate impairment showed the thickened interlobular septa (11/11, 100%), thickened lobular interstitium (9/11, 82%), distorted lobular structures (11/11, 100%) and thickened bronchovascular bundles (10/11, 91%). 16 cases with marked impairment showed the honeycombing (16/16, 100%) and the traction bronchiectasis (9/16, 55%).

CT can provide significant information for the assessment of the pathologic severity of idiopathic pulmonary fibrosis. There is good correlation between CT findings and pulmonary function test results. CT combined with pulmonary function test can predict the progression, long term survival and response to therapy.