The clinical impact of high resolution computed tomography in patients with respiratory disease.

OBJECTIVE: High resolution computed tomography is widely used to investigate patients with suspected diffuse lung disease. Numerous studies have assessed the diagnostic performance of this investigation, but the diagnostic and therapeutic impacts have received little attention. METHODS: The diagnostic and therapeutic impacts of high resolution computed tomography in routine clinical practice were evaluated prospectively. All 507 referrals for high-resolution computed tomography over 12 months in two centres were included. Requesting clinicians completed questionnaires before and after the investigation detailing clinical indications, working diagnoses, confidence level in each diagnosis, planned investigations and treatments. RESULTS: Three hundred and fifty-four studies on 347 patients had complete data and were available for analysis. Following high-resolution computed tomography, a new leading diagnosis (the diagnosis with the highest confidence level) emerged in 204 (58%) studies; in 166 (47%) studies the new leading diagnosis was not in the original differential diagnosis. Mean confidence in the leading diagnosis increased from 6.7 to 8.5 out of 10 (p < 0.001). The invasiveness of planned investigations increased in 23 (7%) studies and decreased in 124 (35%) studies. The treatment plan was modified after 319 (90%) studies. CONCLUSIONS: Thoracic high-resolution computed tomography alters leading diagnosis, increases diagnostic confidence, and frequently changes investigation and management plans.

High-dose acetylcysteine in idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis is a chronic progressive disorder with a poor prognosis. METHODS: We conducted a double-blind, randomized, placebo-controlled multicenter study that assessed the effectiveness over one year of a high oral dose of acetylcysteine (600 mg three times daily) added to standard therapy with prednisone plus azathioprine. The primary end points were changes between baseline and month 12 in vital capacity and in single-breath carbon monoxide diffusing capacity (DL(CO)). RESULTS: A total of 182 patients were randomly assigned to treatment (92 to acetylcysteine and 90 to placebo). Of these patients, 155 (80 assigned to acetylcysteine and 75 to placebo) had usual interstitial pneumonia, as confirmed by high-resolution computed tomography and histologic findings reviewed by expert committees, and did not withdraw consent before the start of treatment. Fifty-seven of the 80 patients taking acetylcysteine (71 percent) and 51 of the 75 patients taking placebo (68 percent) completed one year of treatment. Acetylcysteine slowed the deterioration of vital capacity and DL(CO): at 12 months, the absolute differences in the change from baseline between patients taking acetylcysteine and those taking placebo were 0.18 liter (95 percent confidence interval, 0.03 to 0.32), or a relative difference of 9 percent, for vital capacity (P=0.02), and 0.75 mmol per minute per kilopascal (95 percent confidence interval, 0.27 to 1.23), or 24 percent, for DL(CO) (P=0.003). Mortality during the study was 9 percent among patients taking acetylcysteine and 11 percent among those taking placebo (P=0.69). There were no significant differences in the type or severity of adverse events between patients taking acetylcysteine and those taking placebo, except for a significantly lower rate of myelotoxic effects in the group taking acetylcysteine (P=0.03). CONCLUSIONS: Therapy with acetylcysteine at a dose of 600 mg three times daily, added to prednisone and azathioprine, preserves vital capacity and DL(CO) in patients with idiopathic pulmonary fibrosis better than does standard therapy alone.