High-resolution CT scan findings in familial interstitial pneumonia do not conform to those of idiopathic interstitial pneumonia.
BACKGROUND
The aim of this study was to describe the high-resolution CT (HRCT) scan features that characterize familial interstitial pneumonia (FIP).


METHODS
FIP was defined by the presence of two or more cases of probable or definite idiopathic interstitial pneumonia (IIP) in individuals related within three degrees. The cases were collected consecutively from three centers. We identified 371 individuals with potential FIP from 289 families, including 340 individuals who had HRCT scans. Two chest radiologists independently reviewed the HRCT scans, scoring the extent and distribution of HRCT scan findings, and assessed the overall radiologic diagnosis.


RESULTS
HRCT scan abnormalities suggestive of IIP were present in 85% (289 of 340 subjects). The most frequent findings were reticular pattern (n = 238, 82%) and ground-glass opacity (GGO) associated with reticular abnormality (n = 231, 80%). Other changes included GGO in 116 (40%), honeycombing in 92 (32%), and micronodules in 65 (22%). In the 289 cases with evidence of IIP, the findings were diffusely distributed in the craniocaudal plane in 186 (64%), and the lower lung zones were predominantly involved in 89 (31%). In the axial plane, 194 (67%) had a subpleural distribution; 88 (30%) were diffuse. The imaging pattern was classified as definite or probable usual interstitial pneumonia (UIP) in only 62 subjects (22%) and definite or probable nonspecific interstitial pneumonia (NSIP) in 35 subjects (12%). In 160 subjects (55%), the imaging findings did not conform to previously described UIP or NSIP patterns.


CONCLUSIONS
Reticulation and a mixed GGO/reticular pattern are the most common HRCT scan findings in FIP. The parenchymal abnormalities are most often diffuse in the craniocaudal dimension and have a predominantly peripheral distribution in the axial dimension. Although a radiologic UIP pattern is not uncommon, most cases do not conform to typical UIP or NSIP patterns.
Division of Radiology, National Jewish Health and University of Colorado, Denver, CO.
Ho Yun
HY
Lee
Division of Radiology, National Jewish Health and University of Colorado, Denver, CO.
Joon Beom
JB
Seo
Department of Medicine, Duke University Medical Center, Durham, NC.
Mark P
MP
Steele
Department of Medicine, National Jewish Health and University of Colorado, Denver, CO.
Marvin I
MI
Schwarz
Department of Medicine, National Jewish Health and University of Colorado, Denver, CO.
Kevin K
KK
Brown
Division of Pulmonary, Vanderbilt University School of Medicine, Nashville, TN.
James E
JE
Loyd
Department of Medicine, National Jewish Health and University of Colorado, Denver, CO.
Janet L
JL
Talbert
Department of Medicine, National Jewish Health and University of Colorado, Denver, CO.
David A
DA
Schwartz
Division of Radiology, National Jewish Health and University of Colorado, Denver, CO. Electronic address: lynchd@njhealth.org.
David A
DA
Lynch
D000368:Aged; D001706:Biopsy; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D054988:Idiopathic Interstitial Pneumonias / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D017563:Lung Diseases, Interstitial / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*