Idiopathic Pulmonary Fibrosis: Physiologic Tests, Quantitative CT Indexes, and CT Visual Scores as Predictors of Mortality

Purpose: To retrospectively evaluate quantitative computed tomographic (CT) indexes, pulmonary function test results, and visual CT scoring as predictors of mortality and to describe serial changes in quantitative CT indexes over 12 months in patients with idiopathic pulmonary fibrosis (IPF).

Materials and Methods: Institutional review board approval and informed consent were obtained at all participating institutions. One hundred sixty-seven patients (110 men, 57 women; mean age, 63 years ± 9 [standard deviation]) with IPF were enrolled in a clinical trial. Patients underwent thin-section CT in the supine position at full inspiration at enrollment (baseline) and at 12-month follow-up. After segmentation of the lungs, mean lung attenuation (MLA), skewness, and kurtosis were measured. Extent of ground glass opacity and lung fibrosis were assessed visually. Forced vital capacity (FVC) and total lung capacity (TLC) were measured. Median duration of follow-up for mortality was 1.5 years. Univariate and multivariate survival analyses were used to determine the predictive value of baseline variables for survival.

Results: At univariate analysis, baseline variables predictive of death included TLC, fibrosis, skewness, and kurtosis. At multivariate analysis, FVC (P = .006) and fibrosis (P = .002) were predictors of short-term mortality. In 95 patients who had both baseline and follow-up CT scans, fibrosis (P = .030), MLA (P = .003), skewness (P < .001), and kurtosis (P < .001) all showed change indicating disease progression.

Conclusion: Visually determined disease extent on CT images is a strong independent predictor of mortality in IPF. Serial evaluation of quantitative CT measures can show disease progression in these patients.

© RSNA, 2008

References

  • 1 Lynch DA, Godwin JD, Safrin S, et al. High-resolution computed tomography in idiopathic pulmonary fibrosis: diagnosis and prognosis. Am J Respir Crit Care Med 2005; 172: 488–493. Crossref, MedlineGoogle Scholar
  • 2 Best AC, Lynch AM, Bozic CM, Miller D, Grunwald GK, Lynch DA. Quantitative CT indexes in idiopathic pulmonary fibrosis: relationship with physiologic impairment. Radiology 2003;228:407–414. LinkGoogle Scholar
  • 3 American Thoracic Society. Idiopathic pulmonary fibrosis: diagnosis and treatment. International consensus statement. American Thoracic Society (ATS), and the European Respiratory Society (ERS). Am J Respir Crit Care Med 2000;161:646–664. Crossref, MedlineGoogle Scholar
  • 4 Crapo RO, Morris AH, Gardner RM. Reference spirometric values using techniques and equipment that meet ATS recommendations. Am Rev Respir Dis 1981;123:659–664. MedlineGoogle Scholar
  • 5 American Thoracic Society/European Respiratory Society International Multidisciplinary Consensus Classification of the Idiopathic Interstitial Pneumonias. Am J Respir Crit Care Med 2002;165:277–304. Crossref, MedlineGoogle Scholar
  • 6 Travis WD, Matsui K, Moss J, Ferrans VJ. Idiopathic nonspecific interstitial pneumonia: prognostic significance of cellular and fibrosing patterns—survival comparison with usual interstitial pneumonia and desquamative interstitial pneumonia. Am J Surg Pathol 2000;24:19–33. Crossref, MedlineGoogle Scholar
  • 7 Bjoraker J, Ryu J, Edwin M, et al. Prognostic significance of histopathologic subsets in idiopathic pulmonary fibrosis. Am J Respir Crit Care Med 1998;157:199–203. Crossref, MedlineGoogle Scholar
  • 8 Douglas WW, Ryu JH, Schroeder DR. Idiopathic pulmonary fibrosis: impact of oxygen and colchicine, prednisone, or no therapy on survival. Am J Respir Crit Care Med 2000;161:1172–1178. Crossref, MedlineGoogle Scholar
  • 9 Zisman DA, Lynch JP 3rd, Toews GB, Kazerooni EA, Flint A, Martinez FJ. Cyclophosphamide in the treatment of idiopathic pulmonary fibrosis: a prospective study in patients who failed to respond to corticosteroids. Chest 2000;117:1619–1626. Crossref, MedlineGoogle Scholar
  • 10 Crystal RG, Bitterman PB, Mossman B, et al. Future research directions in idiopathic pulmonary fibrosis: summary of a National Heart, Lung, and Blood Institute working group. Am J Respir Crit Care Med 2002;166:236–246. Crossref, MedlineGoogle Scholar
  • 11 Raghu G, Brown KK, Bradford WZ, et al. A placebo-controlled trial of interferon gamma-1b in patients with idiopathic pulmonary fibrosis. N Engl J Med 2004;350:125–133. Crossref, MedlineGoogle Scholar
  • 12 Hunninghake GW, Lynch DA, Galvin JR, et al. Radiologic findings are strongly associated with a pathologic diagnosis of usual interstitial pneumonia. Chest 2003;124:1215–1223. Crossref, MedlineGoogle Scholar
  • 13 Muller N, Staples C, Miller R, Abboud R. An objective method to quantitate emphysema using computed tomography. Chest 1988;94:782–787. Crossref, MedlineGoogle Scholar
  • 14 Kinsella M, Muller NL, Abboud RT, Morrison NJ, DyBuncio A. Quantitation of emphysema by computed tomography using a “density mask” program and correlation with pulmonary function tests. Chest 1990;97:315–321. Crossref, MedlineGoogle Scholar
  • 15 Uppaluri R, Mitsa T, Sonka M, Hoffman EA, McLennan G. Quantification of pulmonary emphysema from lung computed tomography images. Am J Respir Crit Care Med 1997;156:248–254. Crossref, MedlineGoogle Scholar
  • 16 Chabat F, Yang GZ, Hansell DM. Obstructive lung diseases: texture classification for differentiation at CT. Radiology 2003;228:871–877. LinkGoogle Scholar
  • 17 Uppaluri R, Hoffman EA, Sonka M, Hunninghake GW, McLennan G. Interstitial lung disease: a quantitative study using the adaptive multiple feature method. Am J Respir Crit Care Med 1999;159:519–525. Crossref, MedlineGoogle Scholar
  • 18 Rodriguez LH, Vargas PF, Raff U, et al. Automated discrimination and quantification of idiopathic pulmonary fibrosis from normal lung parenchyma using generalized fractal dimensions in high-resolution computed tomography images. Acad Radiol 1995;2:10–18. Crossref, MedlineGoogle Scholar
  • 19 Beinert T, Kohz P, Seemann M, Egge T, Reiser M, Behr J. Spirometrically controlled high resolution computed tomography: quantitative assessment of density distribution in patients with diffuse fibrosing alveolitis. Eur J Med Res 1996;1:269–272. MedlineGoogle Scholar
  • 20 Hartley PG, Galvin JR, Hunninghake GW, et al. High-resolution CT-derived measures of lung density are valid indexes of interstitial lung disease. J Appl Physiol 1994;76:271–277. Crossref, MedlineGoogle Scholar
  • 21 Stoel BC, Vrooman HA, Stolk J, Reiber JH. Sources of error in lung densitometry with CT. Invest Radiol 1999;34:303–309. Crossref, MedlineGoogle Scholar
  • 22 Shaker SB, Dirksen A, Laursen LC, Skovgaard LT, Holstein-Rathlou NH. Volume adjustment of lung density by computed tomography scans in patients with emphysema. Acta Radiol 2004;45:417–423. Crossref, MedlineGoogle Scholar
  • 23 Lamers RJ, Kemerink GJ, Drent M, van Engelshoven JM. Reproducibility of spirometrically controlled CT lung densitometry in a clinical setting. Eur Respir J 1998;11:942–945. Crossref, MedlineGoogle Scholar

Article History

Published in print: 2008