Usual interstitial pneumonia and chronic idiopathic interstitial pneumonia: analysis of CT appearance in 92 patients.
OBJECTIVE
To retrospectively analyze computed tomographic (CT) findings of chronic idiopathic interstitial pneumonia (IIP) and to determine which findings are most helpful for distinguishing IIP from usual interstitial pneumonia (UIP) with univariate and multivariate analyses.


METHODS
Institutional review board approval and informed consent were not required for this retrospective review of patient records and images. Two observers working independently and without knowledge of the diagnosis evaluated the extent and distribution of various thin-section CT findings (ground-glass opacity, consolidation, reticulation, and honeycombing) in 92 patients (51 men, 41 women; mean age, 56 years; age range, 29-81 years) with a histologic diagnosis of UIP (n = 20), cellular nonspecific interstitial pneumonia (NSIP) (n = 16), fibrotic NSIP (n = 16), respiratory bronchiolitis-associated interstitial lung disease (RB-ILD) (n = 11), desquamative interstitial pneumonia (DIP) (n = 15), or lymphoid interstitial pneumonia (LIP) (n = 14). Observers used univariate and multivariate statistical analyses to compare their findings with the extent and distribution of UIP.


RESULTS
Observers made the correct diagnosis in 145 (79%) of 184 readings. Multivariate logistic regression analysis showed that the independent findings that distinguished UIP from cellular NSIP were the extent of honeycombing and the most proximal bronchus with traction bronchiectasis (odds ratio, 5.16 and 0.37, respectively); the finding that distinguished UIP from fibrotic NSIP was the extent of honeycombing (odds ratio, 2.10). CT features that distinguished UIP from RB-ILD and DIP included extent of ground-glass opacity (odds ratio, 0.76), thickening of bronchovascular bundles (odds ratio, 1.58), the most proximal bronchus with traction bronchiectasis (odds ratio, 0.22), and the number of segments with traction bronchiectasis (odds ratio, 3.64).


CONCLUSIONS
UIP has a characteristic appearance that usually facilitates distinction from other types of chronic IIPs at thin-section CT. The most useful finding when differentiating UIP from NSIP was the extent of honeycombing.
Sumikawa
Hiromitsu
H
Department of Radiology and Medical Physics, Osaka University Graduate School of Medicine, Osaka, Japan. h-sumikawa@radiol.med.osaka-u.ac.jp
Johkoh
Takeshi
T
Ichikado
Kazuya
K
Taniguchi
Hiroyuki
H
Kondoh
Yasuhiro
Y
Fujimoto
Kiminori
K
Tateishi
Ukihide
U
Hiramatsu
Tetsuo
T
Inoue
Atsuo
A
Natsag
Javzandulam
J
Ikemoto
Minako
M
Mihara
Naoki
N
Honda
Osamu
O
Tomiyama
Noriyuki
N
Hamada
Seiki
S
Nakamura
Hironobu
H
Müller
Nestor L
NL
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001987:Bronchiectasis / Q000000981:diagnostic imaging; D001988:Bronchiolitis / Q000150:complications; D002908:Chronic Disease; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D017563:Lung Diseases, Interstitial / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011658:Pulmonary Fibrosis / Q000000981:diagnostic imaging; D012044:Regression Analysis; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed