High-resolution computed tomography of honeycombing and IPF/UIP: To what extent can honeycomb lung be diagnosed by imaging? To what extent can IPF diagnosis be made by HRCT?

Abstract

Typical and atypical imaging findings, differential diagnosis, complications of disease itself and roles of imaging, and problems in diagnosis of idiopathic pulmonary fibrosis/usual interstitial pneumonia (IPF/UIP) are described. Pathologic hallmarks of IPF/UIP are perilobular/periacinar fibrosis, temporal/spatial heterogeneity, advanced fibrosis, and small concentrated areas of nearly normal lung. Typical high-resolution computed tomographic (HRCT) features of IPF/UIP are subpleurally located reticular opacity or honeycomb lung in the dorsal aspect of bilateral lower lobes. Honeycomb lung (honeycombing) is a key finding in the diagnosis of IPF/UIP, but experienced radiologists sometimes disagree in judging honeycomb lung at HRCT. Early diagnosis of IPF/UIP requires establishment of diagnostic criteria other than honeycombing and investigation of HRCT findings that correspond with temporal and spatial heterogeneity.