Table 5. Key Features according to Different UIP Category on High-Resolution CT with Its Correspondence to ILA/NSIP.

	Typical UIP [8, 9]	Probable UIP [8, 9]	Indeterminate for UIP [8, 9]	Most consistent with non-IPF [8, 9]
Basal and subpleural predominant distribution	+	+	−; Variable/diffuse
Heterogeneity	+	+
Distortion	+	+	Subtle
GGO		±	±
Peripheral traction bronchiectasis or bronchiolectasis	+	+	-
Honeycombing	+	-	-
ILA defined by CT [10]		Subpleural	Subpleural	Non-Subpleural
		Fibrotic ILA	Non-Fibrotic ILA	ILA
NSIP defined by pathology [37]		Progressive NSIP	Fibrosing NSIP	Cellular NSIP

GGO = ground-glass opacities, ILA = interstitial lung abnormality, IPF = idiopathic pulmonary fibrosis, NSIP = nonspecific interstitial pneumonia, UIP = usual interstitial pneumonia