Table 1.

Summary of studies contributing to change in IPF diagnostic guidelines

Study author, reference	Patient subgroup	HRCT results	SLB results	Diagnosis by 2011 guidelines [14]	Notes
Cohort study involving 201 patients with pulmonary fibrosis who underwent lung biopsy within 1 year of chest CT scan
Chung [24]	Probable UIP*	Reticulation, little or no honeycombing	Definite*/probable* UIP 82%	IPF	Probable UIP* by HRCT was more likely to have UIP confirmed by SLB than indeterminate UIP* by HRCT
			Indeterminate*18%	Probable IPF
	Indeterminate for UIP*	Indeterminate	Definite*/probable* UIP 54%	IPF
			Indeterminate*46%	Probable IPF
Post-hoc analysis of pooled data from the INPULSIS trials on 1061 patients with honeycombing and/or diagnosis of UIP by SLB
Raghu [25]	Honeycombing or SLB	Honeycombing	Not specified	IPF	Disease progression & response to nintedanib similar between groups
		Not specified	UIP
	No honeycombing or SLB	Features of possible UIP and traction bronchiectasis, no honeycombing	None available	SLB required

^*Definite UIP: peripheral and basilar predominant pulmonary fibrosis characterized by reticulation, honeycombing, and absence of findings to suggest another specific diagnosis; probable UIP: peripheral and basilar predominant pulmonary fibrosis with reticulation, little/no honeycombing but with otherwise typical features of UIP; indeterminate UIP: pulmonary fibrosis with imaging findings not sufficient to reach a definite, probable, or inconsistent with UIP diagnosis [24]

CT Computed tomography, HRCT High-resolution computed tomography, IPF Idiopathic pulmonary fibrosis, SLB Surgical lung biopsy, UIP Usual interstitial pneumonia