Fig 1.
CT images for standard reference cases of emphysema and fibrosis.
(A) The extent of emphysema was visually scored on a six-point scale. (B) The extent of fibrosis was also visually assessed on a five-point scale for reticulation, honeycombing, and total fibrosis.
Fig 2.
Flowchart of patient selection.
UIP = usual interstitial pneumonia, SRIF = smoking-related interstitial fibrosis.
Fig 3.
Six standard reference CT images for characterization of FILA.
FILA = fibrotic interstitial lung abnormality.
Table 1.
Comparison of Demographics and Imaging Analysis in UIP without Emphysema, UIP with Emphysema and SRIF Groups with Post-hoc Tests.
Fig 4.
Kaplan-Meier survival curves stratified by three groups, UIP without emphysema, UIP with emphysema and SRIF.
The highest survival rate was observed for patients with SRIF (mean survival: 8.79 ± 0.78 years), and this was significantly higher than survival in UIP with emphysema (median survival: 4.10 ± 1.96 years, p = 0.035) and UIP without emphysema (median survival: 2.95 ± 1.06 years, p = 0.026).
Table 2.
Comparison of Fibrotic Interstitial Lung Abnormalities on CT in UIP without Emphysema, UIP with Emphysema and SRIF Groups.
Table 3.
Comparison of CT Scores between UIP with Emphysema and SRIF Groups.
Fig 5.
HRCT images and pathologic features of a 66-year-old man who was categorized as UIP without emphysema.
(A), (B) HRCT shows subpleural honeycombing predominantly in the lower lobes without emphysema (C), (D) Pathologic features show dense fibrosis with architectural distortion, microscopic honeycomb change (C, x20), and often fibroblastic foci (arrow), (D, x200). He was considered to have idiopathic pulmonary fibrosis, and pSRIF score was -2.
Fig 6.
HRCT images and pathologic features of a 64-year-old man who have possible UIP pattern with emphysema.
(A), (B) HRCT shows upper lobe-predominant paraseptal emphysema and symmetric honeycombing in lower lobes. (C) Pathologic features show dense fibrosis with severe architectural distortion (x40). He was diagnosed with IPF after multidisciplinary discussion between pulmonologists, radiologists, and pathologists, and the pSRIF score was -3.
Fig 7.
HRCT images and pathologic features of a 67-year-old man who was diagnosed with SRIF in pathology.
(A), (B) HRCT shows upper lobe-predominant paraseptal emphysema, and asymmetric, inhomogeneous honeycombing with bullae in the lower lobes. (C, D) Pathologic features show emphysematous change, interstitial fibrosis and dense fibrosis with architectural distortion and fibroblastic focus (x20, x40). He was diagnosed with SRIF by multidisciplinary discussion, because also he was not suspicious to have IPF in clinical information. The pSRIF score was 2.