Pulmonary Function Tests and CT Scan in the Management of Idiopathic Pulmonary Fibrosis

Relationships between pulmonary function testing and high-resolution computed tomography (HRCT) were studied in 39 untreated patients with idiopathic pulmonary fibrosis (IPF) at diagnosis, 23 of whom were followed during 7.5 ± 0.3 mo (mean ± SEM). At diagnosis, the extent of overall lung involvement in the HRCT scans showed a moderate but significant correlation only with FVC (r = − 0.46, p = 0.003) and Dl CO (r = − 0.40, p = 0.03). The extent of ground glass pattern also correlated with FVC (r = − 0.58, p = 0.0001). Arterial Po 2 at peak exercise (n = 13 patients) showed a significant association with the extent of both ground-glass pattern and overall lung involvement in HRCT (r = − 0.60, p = 0.02; and r = − 0.64, p = 0.01, respectively). On multivariate analysis a significant independent correlation between the global disease extent in HRCT and both FVC and Dl CO was observed. Changes over time in the total extent of the disease evaluated with HRCT scans were also related to those observed in Dl CO and in FVC (r = − 0.57, p = 0.01, and r = − 0.51, p = 0.01, respectively). The present study suggests that FVC and Dl CO are the physiological variables that best reflect the global extent of disease in IPF and thus may provide significant information for the assessment of the disease's progression.