Differentiating combined pulmonary fibrosis and emphysema from pure emphysema: utility of late gadolinium-enhanced MRI

Hannah Fleming,Edward Mckone,Jonathan D Dodd,Niall Mcveigh,Simon M Clifford,David A Lynch,Aurelie Fabre,Suhny Abbara,David J Murphy,Lisa Lavelle,Roisin Macdermott,Gerard M Healy,Peter Doran,Michael P Keane,Cormac Mccarthy,Marcus Butler,Aoife Haughey

doi:10.1186/s41747-020-00187-w

Abstract

BackgroundDifferentiating combined pulmonary fibrosis with emphysema (CPFE) from pure emphysema can be challenging on high-resolution computed tomography (HRCT). This has antifibrotic therapy implications.MethodsTwenty patients with suspected CPFE underwent late gadolinium-enhanced (LGE) thoracic magnetic resonance imaging (LGE-MRI) and HRCT. Data from twelve healthy control subjects from a previous study who underwent thoracic LGE-MRI were included for comparison. Quantitative LGE signal intensity (SI) was retrospectively compared in regions of fibrosis and emphysema in CPFE patients to similar lung regions in controls. Qualitative comparisons for the presence/extent of reticulation, honeycombing, and traction bronchiectasis between LGE-MRI and HRCT were assessed by two readers in consensus.ResultsThere were significant quantitative differences in fibrosis SI compared to emphysema SI in CPFE patients (25.8, IQR 18.4–31.0 versus 5.3, IQR 5.0–8.1, p < 0.001). Significant differences were found between LGE-MRI and HRCT in the extent of reticulation (12.5, IQR 5.0–20.0 versus 25.0, IQR 15.0–26.3, p = 0.038) and honeycombing (5.0, IQR 0.0–10.0 versus 20.0, IQR 10.6–20.0, p = 0.001) but not traction bronchiectasis (10.0, IQR 5–15 versus 15.0, IQR 5–15, p = 0.878). Receiver operator curve analysis of fibrosis SI compared to similarly located regions in control subjects showed an area under the curve of 0.82 (p = 0.002). A SI cutoff of 19 yielded a sensitivity of 75% and specificity of 86% in differentiating fibrosis from similarly located regions in control subjects.ConclusionLGE-MRI can differentiate CPFE from pure emphysema and may be a useful adjunct test to HRCT in patients with suspected CPFE.

Highlights

Differentiating combined pulmonary fibrosis with emphysema (CPFE) from pure emphysema can be challenging on high-resolution computed tomography (HRCT)
In this study, we retrospectively took into consideration the late gadolinium-enhanced (LGE)-MRI scans acquired between April 2016 and March 2019 in 20 patients with CPFE suspected at HRCT
Baseline data The median age of the control group was significantly lower than the CPFE group (51.5 years, Interquartile range (IQR) 41.8–62.8 versus 72.0 years, IQR 67.8-77.3, p < 0.001) (Table 1)

Summary

Introduction

Differentiating combined pulmonary fibrosis with emphysema (CPFE) from pure emphysema can be challenging on high-resolution computed tomography (HRCT). Accurately identifying regions of definite fibrosis on HRCT can sometimes be challenging Mimickers of honeycombing such as paraseptal emphysema may cause difficulty in confidently and accurately diagnosing cystic lung disease [9]. This is true of cases with alternative fibrotic patterns to usual interstitial pneumonia [10]. Other patients may present with clinically suspected interstitial pulmonary fibrosis (IPF) but with obstructive spirometry In both instances, accurate imaging of the underlying disease processes is important for diagnosis and treatment

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Results

Conclusion