title: Relative preservation of peripheral lung function in smoking-related pulmonary emphysema: assessment with 99mTc-MAA perfusion and dynamic 133Xe SPET.
abstract: In this study the cross-sectional functional differences between the central and peripheral lung in smokers with pulmonary emphysema were evaluated by lung perfusion and dynamic xenon-133 single-photon emission tomography (SPET). The subjects were 81 patients with a long-term smoking history and relatively advanced emphysema, 17 non-smoker patients with non-obstructive lung diseases and six healthy non-smokers. Regional lung functional difference between the peripheral and central lung was assessed in the upper, middle and lower lung zones by technetium-99m macroaggregated albumin SPET and dynamic 133Xe SPET. The distribution of emphysematous changes was assessed by density-mask computed tomography (CT) images which depicted abnormally low attenuation areas (LAAs) of less than -960 Hounsfield units. Two hundred and eighty-eight (59.2%) lung zones of 63 (77.7%) patients with pulmonary emphysema showed relative preservation of lung function in the peripheral lung, with a curvilinear band of normal perfusion (a stripe sign) and a significantly faster 133Xe half-clearance time (T(1/2)) than in central lung (P<0.0001). Of these lung zones, 256 (88.8%) showed central-dominant LAA distributions on density-mask CT images, but the remaining 32 zones did not show any regional preference in LAA distribution. Conversely, 117 (24.0%) lung zones of 19 (23.4%) patients showed periphery-dominant perfusion defects and LAA distributions, with significantly prolonged T(1/2) in the peripheral lung area (P<0.0001). The remaining 81 lung zones of the patients with pulmonary emphysema and all the lung zones of the healthy subjects and patients with non-obstructive lung diseases did not show a stripe sign, and no differences were observed in T(1/2) values and LAA distributions between the central and peripheral lung. Relative preservation of peripheral lung function seems to be a characteristic feature in smoking-related pulmonary emphysema, and may indicate a lower susceptibility of peripheral parenchyma to the development of this disease.
authors.affiliation: Department of Radiology, Yamaguchi University School of Medicine, Ube, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Suga
authors.forename: N
authors.initials: N
authors.lastname: Kume
authors.forename: N
authors.initials: N
authors.lastname: Matsunaga
authors.forename: N
authors.initials: N
authors.lastname: Ogasawara
authors.forename: K
authors.initials: K
authors.lastname: Motoyama
authors.forename: A
authors.initials: A
authors.lastname: Hara
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
mesh_terms: D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D019275:Radiopharmaceuticals; D012907:Smoking / Q000009:adverse effects*; D013668:Technetium Tc 99m Aggregated Albumin; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed / Q000379:methods; D014980:Xenon Radioisotopes
chemical_list: D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin; D014980:Xenon Radioisotopes