Multidisciplinary Approach to Diagnosis of IPF

Reprinted with permission of the American Thoracic Society. Copyright © 2014 American Thoracic Society. Raghu G, Collard HR, Egan JJ, et al. An official ATS/ERS/JRS/ALAT statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management. Am J Respir Crit Care Med. 2011;183:788-824. Official Journal of the American Thoracic Society. Note: this document was published in 2011 and is currently in revision. Certain aspects of this document may be out of date and caution should be used when applying these in clinical practice or other usages.

Combining HRCT and Histopathologic Findings

According to the 2011 evidence-based guidelines, combining HRCT and histopathologic findings in a grid-like format, as shown in Table 5, can help the clinician determine if idiopathic pulmonary fibrosis is present.⁸⁴⁰ Given the clinical, pathologic, and radiographic nuances required to diagnose IPF, it is not surprising that a multidisciplinary approach improves diagnostic confidence.⁴⁷

A multidisciplinary approach involving ILD experts including clinicians, radiologists, and pathologists familiar with IPF is recommended by ATS/ERS/JRS/ALAT.⁸ When a multidisciplinary approach involving discussion among ILD experts is not available or feasible in local clinical practices, it is recommended that patients be referred to regional centers with expertise in the evaluation and management of ILD.⁸

In the absence of a UIP pattern on HRCT, IPF can be diagnosed by specific combinations of HRCT and histopathologic patterns in patients who undergo surgical lung biopsy.⁸

Table 5.
Combinations of HRCT patterns and surgical lung biopsy patterns which, in consultation with ILD experts, can lead to the diagnosis of IPF. Reprinted with permission of the American Thoracic Society. Copyright © 2014 American Thoracic Society. Raghu G, Collard HR, Egan JJ, et al. An official ATS/ERS/JRS/ALAT statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management. Am J Respir Crit Care Med. 2011;183:788-824. Official Journal of the American Thoracic Society. Note: this document was published in 2011 and is currently in revision. Certain aspects of this document may be out of date and caution should be used when applying these in clinical practice or other usages.

HRCT Pattern*	Surgerical Lung Biopsy Pattern* (when performed)	Diagnosis of IPF?ƚ
UIP	UIP Probable UIP Possible UIP Nonclassifiable fibrosis‡ Not UIP	YES No
Possible UIP	UIP Probable UIP Possible UIP Nonclassifiable fibrosis‡ Not UIP	YES Probable No
Inconsistent with UIP	UIP Probable UIP Possible UIP Nonclassifiable fibrosis‡ Not UIP	Possible No

HRCT, high-resolution computed tomography; IPF, idiopathic pulmonary fibrosis; UIP, usual interstitial pneumonia.
Bold type indicates combinations of HRCT and surgical lung biopsy patterns that correspond with a diagnosis of IPF (YES in the far right column).
*Patterns described in Tables 3 and 4.
^ƚThe accuracy of the diagnosis of IPF increases with multidisciplinary discussion.
^‡Nonclassifiable fibrosis: Some biopsies may reveal a pattern of fibrosis that does not meet the above criteria for UIP pattern and the other idiopathic interstitial pneumonias. These biopsies may be termed “nonclassifiable fibrosis.”

A multidisciplinary approach has been shown to improve diagnostic accuracy and has become the standard in the diagnosis of IPF and other ILDs.⁹

Figure 5 outlines the recommended step-by-step procedures in the 2011 ATS/ERS/JRS/ALAT guidelines for the diagnosis of IPF.⁸

Figure 5.
Diagnostic algorithm for idiopathic pulmonary fibrosis. Reprinted with permission of the American Thoracic Society. Copyright © 2014 American Thoracic Society. Raghu G, Collard HR, Egan JJ, et al. An official ATS/ERS/JRS/ALAT statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management. Am J Respir Crit Care Med. 2011;183:788-824. Official Journal of the American Thoracic Society. Note: this document was published in 2011 and is currently in revision. Certain aspects of this document may be out of date and caution should be used when applying these in clinical practice or other usages.

Content contributed by:
Ryan Hadley, MD
University of Michigan