Radiologic findings are strongly associated with a pathologic diagnosis of usual interstitial pneumonia.
OBJECTIVE
To determine which clinical and radiologic findings are independently associated with a pathologic diagnosis of usual interstitial pneumonia (UIP).


METHODS
We recently reported, using a prospective, multicenter study of patients suspected of having idiopathic interstitial pneumonia (IIP), that a confident diagnosis of UIP made by experienced radiologists was correct in 95% of cases. In the current article, we further analyzed data from this study. Ninety-one patients were entered into the study. Clinical, physiologic, chest radiographic, and CT features were prospectively recorded, and analyzed using univariate and multivariate logistic regression analysis to compare the patients with a histologic diagnosis of UIP with those who received other pathologic diagnoses.


RESULTS
Fifty-four of 91 patients (59%) received a pathologic diagnosis of UIP. The following features recorded at the referring clinical centers were associated with a pathologic diagnosis of UIP on multivariate analysis: lower-lobe honeycombing on high-resolution CT (HRCT) [odds ratio, 11.45], radiographic findings consistent with UIP (odds ratio, 5.73), elevated ratio of FEV(1) to FVC (odds ratio, 4.8), and absence of smoking history (odds ratio, 0.19). On multivariate analysis of specific HRCT features recorded by four experienced chest radiologists, lower-lung honeycombing (odds ratio, 5.36) and upper-lung irregular lines (odds ratio, 6.28) were the only independent predictors of UIP. Using only these two factors, a diagnosis of UIP could be established with a sensitivity of 74%, a specificity of 81%, and a positive predictive value of 85%.


CONCLUSIONS
In patients presenting with a clinical syndrome suggestive of IIP, CT findings of lower-lung honeycombing and upper-lung irregular lines are most closely associated with a pathologic diagnosis of UIP.
Hunninghake
Gary W
GW
Department of Medicine, University of Iowa and Veterans Administration Medical Center, Iowa City, IA 52242, USA. gary-hunninghake@uiowa.edu
Lynch
David A
DA
Galvin
Jeffrey R
JR
Gross
Barry H
BH
Müller
Nestor
N
Schwartz
David A
DA
King
Talmadge E
TE
Lynch
Joseph P
JP
Hegele
Richard
R
Waldron
James
J
Colby
Thomas V
TV
Hogg
James C
JC
D006801:Humans; D017563:Lung Diseases, Interstitial / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology; D015999:Multivariate Analysis; D011446:Prospective Studies; D011859:Radiography