title: Differential CT features of infectious pneumonia versus bronchioloalveolar carcinoma (BAC) mimicking pneumonia.
abstract: The purpose of this study was to evaluate retrospectively the differential CT features of bronchioloalveolar carcinoma (BAC) mimicking pneumonia and infectious pneumonia at the lung periphery. CT images were reviewed in 47 patients with focal areas of parenchymal opacification at the lung periphery. We evaluated the presence of ground-glass attenuation, marginal conspicuity of the lesion, CT angiogram sign, air-bronchogram sign, a bubble-like low-attenuation area within the lesion, presence of pleural thickening and retraction associated with the lesion, presence of pleural effusion and extra-pleural fatty hypertrophy, presence of bronchial wall thickening proximal to the lesion, and air-trapping in the normal lung near the lesion. BAC (n=18) depicted the presence of a bubble-like low-attenuation area within the lesion, whereas infectious pneumonia (n=29) represented the pleural thickening associated with the lesion and bronchial wall thickening proximal to the lesion (P<0.05). The other CT findings showed no significant differences (P>0.05). The focal areas of the parenchymal opacification on the CT images may suggest infectious pneumonia rather than BAC when they show bronchial wall thickening proximal to the lesion and pleural thickening associated with the lesion, whereas BAC is characterized as the presence of a bubble-like low attenuation area within the tumor.
authors.affiliation: Department of Radiology, Yonsei University College of Medicine, Seoul 120-749, South Korea. thkim1@yumc.yonsei.ac.kr
authors.forename: Tae Hoon
authors.initials: TH
authors.lastname: Kim
authors.forename: Sang Jin
authors.initials: SJ
authors.lastname: Kim
authors.forename: Young Hoon
authors.initials: YH
authors.lastname: Ryu
authors.forename: Soo Yoon
authors.initials: SY
authors.lastname: Chung
authors.forename: Jae Seung
authors.initials: JS
authors.lastname: Seo
authors.forename: Young Jin
authors.initials: YJ
authors.lastname: Kim
authors.forename: Byoung Wook
authors.initials: BW
authors.lastname: Choi
authors.forename: Sun Hwa
authors.initials: SH
authors.lastname: Lee
authors.forename: Sang Ho
authors.initials: SH
authors.lastname: Cho
mesh_terms: D002282:Adenocarcinoma, Bronchiolo-Alveolar / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000000981:diagnostic imaging* / Q000382:microbiology; D011237:Predictive Value of Tests; D013902:Radiography, Thoracic; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide