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Idiopathic Pulmonary Fibrosis Imaging

  • Author: Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR; Chief Editor: Kavita Garg, MD  more...
 
Updated: Oct 04, 2015
 

Overview

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive pulmonary disease of unknown etiology. It is primarily diagnosed on the basis of clinical, physiologic, and radiologic criteria. In its International Consensus statement, the American Thoracic Society defines IPF as a specific chronic interstitial pneumonia that is limited to the lung and that has the histologic appearance of usual interstitial pneumonia (UIP) on open or thoracoscopic biopsy. No specific pathognomonic clinical or pathologic findings are associated with IPF, and the diagnosis is made after other causes of interstitial lung disease are excluded.[1, 2, 3, 4, 5, 6, 7] Radiologic characteristics of pulmonary fibrosis appear in the image below.

HRCT of advanced stage of pulmonary fibrosis demon HRCT of advanced stage of pulmonary fibrosis demonstrating reticular opacities with honeycombing, with predominant subpleural distribution.

The diagnosis is confirmed with a lung biopsy, but the histology shows striking variation from one region to the next (ie, the disease is characterized by histologic temporal and spatial heterogeneity). It is not unusual to find areas of normal lung next to areas with severe thickening of alveolar walls. Therefore, findings on bronchoscopic or percutaneous lung biopsy are difficult to interpret. Open lung biopsy and video-assisted thoracoscopic lung biopsy are the preferred methods.

IPF usually affects patients 50-70 years of age. Most series report a male preponderance, with a male-to-female ratio of 2:1. Clinical features consist of progressive exertional dyspnea; the presence of interstitial infiltrates, as evidenced on chest radiographs; and physiologic evidence of restriction and impaired gas exchange on pulmonary function testing.

Patients are generally treated with corticosteroids, other immunosuppressants, or both.

The prognosis of patients with IPF is poor; most patients die of respiratory failure. The mean survival is approximately 4 years.

Preferred examination

The diagnosis of IPF is made on the basis of the patient's history, clinical findings, pulmonary physiology, and imaging results. The diagnosis is one of exclusion. Nonidiopathic causes must be excluded first because of the important therapeutic implications. After nonidiopathic causes are excluded, further investigation of patients with IPF typically reveals radiographic abnormalities and restrictive lung physiology with decreased diffusion capacity.[8, 9, 10]

Plain chest radiography is usually the first investigation performed for patients with suspected interstitial lung disease. However, the findings on conventional radiography are highly nonspecific.

High-resolution computed tomography (HRCT) scanning defines the underlying lung parenchymal abnormalities better than does plain radiography.[11, 12]

Studies have shown that HRCT may obviate surgical lung biopsy in some patients. Raghu et al compared the diagnostic accuracy of clinical evaluation in combination with HRCT with the accuracy of histology of surgical lung-biopsy samples.[13] Clinical assessment in conjunction with careful review of HRCT scans was 60% sensitive and 97% specific for IPF. However, although HRCT may obviate the need for tissue diagnosis in 60% of patients, surgical lung biopsy is still needed in 40%.

For diagnoses other than IPF, a combination of clinical assessment and HRCT is neither sensitive nor specific enough to be relied on without surgical biopsy. Open lung biopsy remains the criterion standard. In immunocompetent patients, the benefit is relatively low because corticosteroid therapy is frequently administered after biopsy. In immunocompromised patients, approaches to therapy change substantially after tissue confirmation, but the mortality rate is high. Therefore, open biopsy should be performed only in patients in whom the diagnosis is likely to change therapy and in patients who have a reasonable prognosis.

Radionuclide scanning with gallium-67 may depict interstitial fibrosis and may show changes early. This feature may be of therapeutic benefit, but the changes are nonspecific and do not obviate the need for lung biopsy.

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Radiography

The radiographic pattern differs with the stage of the disease. Early in the disease, the most common radiographic changes are an interstitial shadowing of small (1- to 2-mm), irregular opacities, which are seen in about three fourths of patients. Less common are small, round opacities, which are seen in one fifth of patients. This finding is generally known as reticulonodular opacities. Septal lines are occasionally observed. The distribution is predominantly basal. (See the image below.)

Bilateral lower lobe opacities and possible mild d Bilateral lower lobe opacities and possible mild decrease in lung volumes. Courtesy of Sat Sharma, MD, FRCPC, FACP, FCCP, DABSM.

Peripheral accentuation is also a common feature, but it is more easily appreciated on CT scans than on plain chest radiographs.

The pattern is usually symmetrical. Another common pattern is hazy, ground-glass opacification, which is either diffuse or patchy. Volume loss and a raised diaphragm are seen in up to 60% of patients. This may be accompanied by basal discoid atelectasis.

Pleural disease is not typical of IPF. Its presence should raise the possibility of other conditions, such as asbestosis, rheumatoid pulmonary disease, or systemic lupus. Pneumothorax, pneumomediastinum, or both have been reported in a few patients; these conditions have been associated with bullae in the lung parenchyma.

With progression of alveolitis to fibrosis, the initial fine lines become coarse, and small (2-mm) cysts appear. These cysts coalesce and increase to 5-7 mm in diameter; they appear as ring opacities within the honeycomb lung. As fibrosis worsens, the honeycombing becomes coarser with larger honeycomb cysts, and further volume loss occurs. In advanced stages, there is radiographic evidence of pulmonary arterial hypertension.

Degree of confidence

The radiographic findings are not correlated with the stage of the disease, the histology, the respiratory symptoms, the respiratory function tests, or the prognosis.

In the majority of patients with IPF, the chest radiograph is abnormal at presentation; previous radiographs often will have shown reticular shadowing, even before symptom development.[14] Chest radiography is frequently the first investigation employed for patients with IPF; physiologic testing and HRCT scanning follow.

False positives/negatives

For symptomatic patients in whom the diffusion capacity is abnormal, results of chest radiography may be normal. For other patients, the radiographic appearances are abnormal before clinical symptoms appear. Results of HRCT scanning are abnormal for most patients with IPF.

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Computed Tomography

For patients with IPF, HRCT scan findings may be used to predict outcomes and to guide the treatment, because the findings are well correlated with the histologic pattern of IPF (see the images below). On HRCT, end-stage lung disease is characterized by honeycombing without ground-glass attenuation in typical distribution; with such findings on HRCT, the diagnosis may be made with confidence. This spares patients the risk of invasive diagnostic processes, such as a lung biopsy. In the active stage, scans demonstrate ground-glass attenuations. The active stage of the disease, which is characterized by active alveolitis, is potentially reversible and potentially amenable to treatment, unlike end-stage disease, which is irreversible.[15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26]

HRCT of advanced stage of pulmonary fibrosis demon HRCT of advanced stage of pulmonary fibrosis demonstrating reticular opacities with honeycombing, with predominant subpleural distribution.
High-resolution CT (HRCT) shows increased pulmonar High-resolution CT (HRCT) shows increased pulmonary attenuation with distortion of the pulmonary architecture. Courtesy of Sat Sharma, MD, FRCPC, FACP, FCCP, DABSM.
High-resolution CT (HRCT) shows distortion of the High-resolution CT (HRCT) shows distortion of the pulmonary architecture with thickening of pulmonary interstitium and some areas of ground-glass attenuation. No obvious honeycombing is present. Courtesy of Sat Sharma, MD, FRCPC, FACP, FCCP, DABSM.

On HRCT, IPF is commonly characterized by patchy and predominantly peripheral, subpleural, and bibasilar reticular opacities. The distribution is predominantly posterior. It is often associated with traction bronchiectasis and subpleural honeycombing.

Ground-glass attenuations are relatively uncommon; they usually progress to the more common reticular attenuations and honeycombing. HRCT scans have been reported to show honeycombing in 90% of patients with IPF.

When a trained observer interprets HRCT, the accuracy of a diagnosis of IPF or cryptogenic fibrosing alveolitis (CFA) appears to be about 90%. Such a confident diagnosis is made in about two thirds of patients with histologic UIP.

In cases of suspected IPF in which lung HRCT shows more than 30% ground-glass attenuation, consideration should be given to other diagnoses; alternative diagnoses include desquamative interstitial pneumonitis, idiopathic bronchiolitis obliterans organizing pneumonia, respiratory bronchiolitis–associated interstitial lung disease, hypersensitivity pneumonitis, and nonspecific interstitial pneumonia.

Degree of confidence

The accuracy of the diagnosis of IPF is significantly increased with HRCT, as compared with chest radiography. When a trained observer performs HRCT, the accuracy of the diagnosis is reported to be about 90%.[27]

False positives/negatives

One third of all cases of IPF are missed on HRCT; a confident diagnosis of IPF is made in about two thirds of cases.[27]

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Nuclear Imaging

In cases of IPF, perfusion lung scintigraphy shows nonspecific, subsegmental mismatched perfusion defects. These are not correlated with clinical severity.

Gallium-67 imaging has not proven to be of value in cases of established IPF.[28]

Technetium-99m diethylenetriamine penta-acetic acid (DTPA) is cleared more rapidly when capillary permeability is increased than when it is not, and the findings may provide an index of lung inflammation.[29] Fluorodeoxyglucose (FDG) positron-emission tomography (PET) may show FDG accumulation in the lung bases; such findings correlate with the honeycomb fibrosis seen on high-resolution HRCT.[30, 31, 32, 33, 34]

Win et al studied 13 patients with IPF recruited for 2 thoracic18 F FDG-PET studies performed within 2 weeks of each other. All patients were diagnosed with IPF in consensus at multidisciplinary meetings because of typical clinical, high-resolution CT, and pulmonary function test features. The purpose of the study to investigate the reproducibility of pulmonary18 F FDG-PET in patients with IPF. This study demonstrated that there is excellent short-term reproducibility in pulmonary18 F FDG uptake in patients with IPF.[35]

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Contributor Information and Disclosures
Author

Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR Consultant Radiologist and Honorary Professor, North Manchester General Hospital Pennine Acute NHS Trust, UK

Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR is a member of the following medical societies: American Association for the Advancement of Science, American Institute of Ultrasound in Medicine, British Medical Association, Royal College of Physicians and Surgeons of the United States, British Society of Interventional Radiology, Royal College of Physicians, Royal College of Radiologists, Royal College of Surgeons of England

Disclosure: Nothing to disclose.

Coauthor(s)

Klaus L Irion, MD, PhD Consulting Staff, The Cardiothoracic Centre Liverpool NHS Trust, The Royal Liverpool University Hospital, UK

Klaus L Irion, MD, PhD is a member of the following medical societies: American Roentgen Ray Society, Radiological Society of North America

Disclosure: Nothing to disclose.

Anitha James, MBBS, DMRD, FRCR Specialist Registrar, Manchester Radiology Training Scheme, Hospitals NHS Trust, UK

Disclosure: Nothing to disclose.

Specialty Editor Board

Bernard D Coombs, MB, ChB, PhD Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand

Disclosure: Nothing to disclose.

Chief Editor

Kavita Garg, MD Professor, Department of Radiology, University of Colorado School of Medicine

Kavita Garg, MD is a member of the following medical societies: American College of Radiology, American Roentgen Ray Society, Radiological Society of North America, Society of Thoracic Radiology

Disclosure: Nothing to disclose.

Additional Contributors

Jeffrey A Miller, MD Associate Adjunct Professor of Clinical Radiology, University of Medicine and Dentistry of New Jersey-New Jersey Medical School; Faculty, Department of Radiology, Veterans Affairs of New Jersey Health Care System

Jeffrey A Miller, MD is a member of the following medical societies: American Roentgen Ray Society, Radiology Alliance for Health Services Research, Society of Thoracic Radiology

Disclosure: Nothing to disclose.

Acknowledgements

Alberto Alonso, MD, MRCP Specialist Registrar in Radiology, Department of Radiology, Manchester Royal Infirmary, UK

Alberto Alonso, MD, MRCP is a member of the following medical societies: Radiological Society of North America, Royal College of Physicians, and Royal College of Radiologists

Disclosure: Nothing to disclose.

William Musda, MBBS Specialist Registrar, Diagnostic Radiology, Manchester Radiology Training Sceme, UK

Disclosure: Nothing to disclose.

Velauthan Rudralingam, MB, BCh, BAO, FRCS, FRCR Staff Physician, Gastrointestinal and Body Imaging Block, Hope Hospital and Wytenshawe Hospital, UK

Velauthan Rudralingam, MB, BCh, BAO, FRCS, FRCR is a member of the following medical societies: British Medical Association and Radiological Society of North America

Disclosure: Nothing to disclose.

References
  1. Hansell, DM, Armstrong, P, Lynch DA, H. Page McAdams. Imaging of Diseases of the Chest. 4th ed. St. Louis, Mo:. Mosby. 2005.

  2. Hunninghake GW, Kalica AR. Approaches to the treatment of pulmonary fibrosis. Am J Respir Crit Care Med. 1995 Mar. 151(3 Pt 1):915-8. [Medline].

  3. King TE Jr. Idiopathic pulmonary fibrosis. In: Schwarz MI, King TE Jr, eds. Interstitial Lung Disease. St. Louis, MO:. Mosby-Year Book. 1993: 367-403.

  4. Ryu JH, Colby TV, Hartman TE. Idiopathic pulmonary fibrosis: current concepts. Mayo Clin Proc. 1998 Nov. 73(11):1085-101. [Medline].

  5. du Bois RM. Idiopathic pulmonary fibrosis. Annu Rev Med. 1993. 44:441-50. [Medline].

  6. Agarwal R, Jindal SK. Acute exacerbation of idiopathic pulmonary fibrosis: a systematic review. Eur J Intern Med. 2008 Jun. 19(4):227-35. [Medline].

  7. Ambrosini V, Cancellieri A, Chilosi M, et al. Acute exacerbation of idiopathic pulmonary fibrosis: report of a series. Eur Respir J. 2003 Nov. 22(5):821-6. [Medline].

  8. Pipavath S, Godwin JD. Imaging of the chest: idiopathic interstitial pneumonia. Clin Chest Med. 2004 Dec. 25(4):651-6, v-vi.

  9. Strollo DC. Imaging of idiopathic interstitial lung diseases. Concepts and conundrums. Am J Respir Cell Mol Biol. 2003 Sep. 29(3 Suppl):S10-8. [Medline].

  10. Katzenstein AL, Mukhopadhyay S, Myers JL. Diagnosis of usual interstitial pneumonia and distinction from other fibrosing interstitial lung diseases. Hum Pathol. 2008 Sep. 39(9):1275-94. [Medline].

  11. Kishaba T. Practical management of Idiopathic Pulmonary Fibrosis. Sarcoidosis Vasc Diffuse Lung Dis. 2015 Jul 22. 32 (2):90-8. [Medline].

  12. Oikonomou A. Role of imaging in the diagnosis of diffuse and interstitial lung diseases. Curr Opin Pulm Med. 2014 Sep. 20 (5):517-24. [Medline].

  13. Raghu G. Idiopathic pulmonary fibrosis. A rational clinical approach. Chest. 1987 Jul. 92(1):148-54. [Medline].

  14. Johnston ID, Prescott RJ, Chalmers JC, Rudd RM. British Thoracic Society study of cryptogenic fibrosing alveolitis: current presentation and initial management. Fibrosing Alveolitis Subcommittee of the Research Committee of the British Thoracic Society. Thorax. 1997 Jan. 52(1):38-44. [Medline].

  15. Antonio GE, Wong KT, Hui DS, et al. Thin-section CT in patients with severe acute respiratory syndrome following hospital discharge: preliminary experience. Radiology. 2003 Sep. 228(3):810-5. [Medline].

  16. MacDonald SL, Rubens MB, Hansell DM, et al. Nonspecific interstitial pneumonia and usual interstitial pneumonia: comparative appearances at and diagnostic accuracy of thin-section CT. Radiology. 2001 Dec. 221(3):600-5. [Medline].

  17. Potente G, Bellelli A, Nardis P. Specific diagnosis by CT and HRCT in six chronic lung diseases. Comput Med Imaging Graph. 1992 Jul-Aug. 16(4):277-82. [Medline].

  18. Raghu G. Interstitial lung disease: a diagnostic approach. Are CT scan and lung biopsy indicated in every patient?. Am J Respir Crit Care Med. 1995 Mar. 151(3 Pt 1):909-14. [Medline].

  19. Shah RM, Miller W. Widespread ground-glass opacity of the lung in consecutive patients undergoing CT: Does lobular distribution assist diagnosis?. AJR Am J Roentgenol. 2003 Apr. 180(4):965-8. [Medline].

  20. Wells A. Clinical usefulness of high resolution computed tomography in cryptogenic fibrosing alveolitis. Thorax. 1998 Dec. 53(12):1080-7. [Medline].

  21. Wittram C, Mark EJ, McLoud TC. CT-histologic correlation of the ATS/ERS 2002 classification of idiopathic interstitial pneumonias. Radiographics. 2003 Sep-Oct. 23(5):1057-71. [Medline].

  22. Zompatori M, Calabrò E, Chetta A, et al. [Chronic hypersensitivity pneumonitis or idiopathic pulmonary fibrosis? Diagnostic role of high resolution Computed Tomography (HRCT)]. Radiol Med (Torino). 2003 Sep. 106(3):135-46. [Medline].

  23. Song JW, Koh WJ, Lee KS, Lee JY, Chung MJ, Kim TS, et al. High-resolution CT findings of Mycobacterium avium-intracellulare complex pulmonary disease: correlation with pulmonary function test results. AJR Am J Roentgenol. 2008 Oct. 191(4):1070. [Medline].

  24. Piirilä P, Kivisaari L, Huuskonen O, Kaleva S, Sovijärvi A, Vehmas T. Association of findings in flow-volume spirometry with high-resolution computed tomography signs in asbestos-exposed male workers. Clin Physiol Funct Imaging. 2008 Sep 15. [Medline].

  25. Rogliani P, Mura M, Mattia P, Ferlosio A, Farinelli G, Mariotta S, et al. HRCT and histopathological evaluation of fibrosis and tissue destruction in IPF associated with pulmonary emphysema. Respir Med. 2008 Aug 22. [Medline].

  26. Vrielynck S, Mamou-Mani T, Emond S, Scheinmann P, Brunelle F, de Blic J. Diagnostic value of high-resolution CT in the evaluation of chronic infiltrative lung disease in children. AJR Am J Roentgenol. 2008 Sep. 191(3):914-20. [Medline].

  27. Grenier P, Valeyre D, Cluzel P, et al. Chronic diffuse interstitial lung disease: diagnostic value of chest radiography and high-resolution CT. Radiology. 1991 Apr. 179(1):123-32. [Medline].

  28. Kataoka M, Kawamura M, Ueda N, et al. Diffuse gallium-67 uptake in radiation pneumonitis. Clin Nucl Med. 1990 Oct. 15(10):707-11. [Medline].

  29. Labrune S, Chinet T, Collignon MA, et al. Mechanisms of increased epithelial lung clearance of DTPA in diffuse fibrosing alveolitis. Eur Respir J. 1994 Apr. 7(4):651-6. [Medline].

  30. Baughman RP, Fernandez M. Radionuclide imaging in interstitial lung disease. Curr Opin Pulm Med. 1996 Sep. 2(5):376-9. [Medline].

  31. Bourke SJ, Hawkins T, Keavey PM, et al. Ventilation perfusion radionuclide imaging in cryptogenic fibrosing alveolitis. Nucl Med Commun. 1993 Jun. 14(6):454-64. [Medline].

  32. James JM, Lloyd JJ, Leahy BC, et al. 99Tcm-Technegas and krypton-81m ventilation scintigraphy: a comparison in known respiratory disease. Br J Radiol. 1992 Dec. 65(780):1075-82. [Medline].

  33. Rizzato G. Is nuclear imaging of any value in managing interstitial fibrosis?. Curr Opin Pulm Med. 1997 Sep. 3(5):372-7. [Medline].

  34. Simkin PH, Licho R, Brill AB. Pulmonary nuclear medicine. Curr Opin Radiol. 1991 Dec. 3(6):859-70. [Medline].

  35. Win T, Lambrou T, Hutton BF, Kayani I, Screaton NJ, Porter JC, et al. 18F-Fluorodeoxyglucose positron emission tomography pulmonary imaging in idiopathic pulmonary fibrosis is reproducible: implications for future clinical trials. Eur J Nucl Med Mol Imaging. 2012 Mar. 39(3):521-8. [Medline].

 
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HRCT of advanced stage of pulmonary fibrosis demonstrating reticular opacities with honeycombing, with predominant subpleural distribution.
Bilateral lower lobe opacities and possible mild decrease in lung volumes. Courtesy of Sat Sharma, MD, FRCPC, FACP, FCCP, DABSM.
High-resolution CT (HRCT) shows increased pulmonary attenuation with distortion of the pulmonary architecture. Courtesy of Sat Sharma, MD, FRCPC, FACP, FCCP, DABSM.
High-resolution CT (HRCT) shows distortion of the pulmonary architecture with thickening of pulmonary interstitium and some areas of ground-glass attenuation. No obvious honeycombing is present. Courtesy of Sat Sharma, MD, FRCPC, FACP, FCCP, DABSM.
Courtesy of Sat Sharma, MD, FRCPC, FACP, FCCP, DABSM. (Click Image to enlarge.)
Courtesy of Sat Sharma, MD, FRCPC, FACP, FCCP, DABSM. (Click Image to enlarge.)
 
 
 
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