Differentiation between mucus secretion and endoluminal tumors in the airway: analysis and comparison of CT findings.
OBJECTIVE
The objective of our study was to suggest CT features that help differentiate transient mucus secretion from airway tumors in the evaluation of soft-tissue nodular lesions confined within the airway lumen.


METHODS
Forty-two patients with airway tumors (mean age, 57.6 ± 14.9 [SD] years) and 48 patients with secretion (mean age, 67.8 ± 13.4 years) were included. Two observers analyzed the following features on contrast-enhanced CT in consensus readings: shape (round, ovoid, lobulating, or complex); margin (circumscribed or uncircumscribed); size (including change in size between mediastinal and lung window images); location (anterior, posterior, or unclear); angle between the lesion and contacting airway wall (acute, obtuse, or unclear); attenuation (quantitative and qualitative analyses); and presence of air, fat, or calcification within the lesion. The positive predictive value (PPV) of each CT finding was calculated for secretion and tumor, respectively.


RESULTS
Round (90.0%) or lobulating (92.9%) shape, uncircumscribed margin (100.0%), unclear location (87.5%), unclear angle (87.5%), a CT number of 21.7 HU or more (91.7%), and internal features such as fat (100.0%) or calcification (100.0%) showed high PPVs for tumors. Complex shape (100.0%), change in size of more than 15.9% (96.8%), a CT number of less than 21.7 HU (83.3%), and internal air density (100.0%) showed high PPVs for secretion.


CONCLUSIONS
On contrast-enhanced CT, the evaluation of shape, change in size between mediastinal and lung window images, the measurement of CT number, and internal features such as air, fat, or calcification might help differentiate secretion from tumors.
1 All authors: Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, South Korea.
Sae Rom
SR
Hong
Yeo Jin
YJ
Lee
Yoo Jin
YJ
Hong
Jin
J
Hur
Young Jin
YJ
Kim
Byoung Wook
BW
Choi
Hye-Jeong
HJ
Lee
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009093:Mucus / Q000000981:diagnostic imaging* / Q000378:metabolism*; D012142:Respiratory Tract Neoplasms / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult