Differentiating Smoking-Related Interstitial Fibrosis (SRIF) from Usual Interstitial Pneumonia (UIP) with Emphysema Using CT Features Based on Pathologically Proven Cases.
OBJECTIVE
To differentiate smoking-related interstitial fibrosis (SRIF) from usual interstitial pneumonia (UIP) with emphysema on CT in combined pulmonary fibrosis and emphysema (CPFE) patients.


METHODS
This study was approved by the institutional review board and informed consent was waived. We included 65 patients who underwent lung biopsy under the suspicion of UIP pattern on HRCT, and after radiologic-pathologic correlation, they were divided into three groups: UIP without emphysema (n = 30), UIP with emphysema (n = 26), and SRIF (n = 9). The quantitative extent of emphysema in the entire lung was visually assessed and fibrotic patterns were qualitatively analyzed based on six characteristics (asymmetry, juxta-subpleural sparing, emphysema beside the honeycombing area, absence of ground grass attenuation/reticulation in honeycombing area, inhomogeneous honeycombing, and absence of honeycombing in the upper lobes). Kaplan-Meier analysis was used for survival analysis, and logistic regression with a receiver operating characteristic curve was used to predict the possibility of SRIF.


RESULTS
In qualitative analysis of fibrotic patterns, SRIF tended to exhibit more than three of six fibrotic features, whereas UIP with emphysema demonstrated about two of these characteristics (p = 0.035). In addition, SRIF had a higher extent of emphysema than UIP with emphysema when they have same amount of fibrosis (p = 0.014). In patients with SRIF, 5-year survival rate was 85.7%, while it was 40.7% in UIP with emphysema patients (p = 0.035).


CONCLUSIONS
Fibrotic CT patterns and survival rate differed between SRIF and UIP with emphysema among CPFE patients, which explains the variable prognosis of CPFE.
Department of Radiology, Chonbuk National University Medical School and Hospital, Institute of Medical Science, Research Institute of Clinical Medicine, Jeonju, Jeonbuk, South Korea.
Kum Ju
KJ
Chae
Department of Radiology, Chonbuk National University Medical School and Hospital, Institute of Medical Science, Research Institute of Clinical Medicine, Jeonju, Jeonbuk, South Korea.
Gong Yong
GY
Jin
Department of Radiology, Chonbuk National University Medical School and Hospital, Institute of Medical Science, Research Institute of Clinical Medicine, Jeonju, Jeonbuk, South Korea.
Hyun Nyeong
HN
Jung
Department of Preventive Medicine, Chonbuk National University Medical School and Hospital, Institute of Medical Science, Research Institute of Clinical Medicine, Jeonju, Jeonbuk, South Korea.
Keun Sang
KS
Kwon
Department of Statistics and Institute of Applied Statistics, Chonbuk National University, Jeonju, Jeonbuk, South Korea.
Hyemi
H
Choi
Department of Internal Medicine, Chonbuk National University Medical School and Hospital, Institute of Medical Science, Research Institute of Clinical Medicine, Jeonju, Jeonbuk, South Korea.
Yong Chul
YC
Lee
Department of Pathology, Chonbuk National University Medical School, Research Institute of Clinical Medicine, Jeonju, Jeonbuk, South Korea.
Myoung Ja
MJ
Chung
Department of Pathology, Chonbuk National University Medical School, Research Institute of Clinical Medicine, Jeonju, Jeonbuk, South Korea.
Ho Sung
HS
Park
D000368:Aged; D001706:Biopsy; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D017563:Lung Diseases, Interstitial / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology; D008297:Male; D011656:Pulmonary Emphysema / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D011658:Pulmonary Fibrosis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology; D012189:Retrospective Studies; D012907:Smoking / Q000009:adverse effects*; D014057:Tomography, X-Ray Computed