title: Clinical significance of ventilation/perfusion scans in collagen disease patients.
abstract: The purpose of this study was to detect disturbances in pulmonary circulation in collagen disease patients by means of a non-invasive technique.
  
  
  METHODS
  Ventilation/perfusion scans with 133Xe gas and 99mTc-macroaggregated albumin (MAA) were performed in 109 patients with various collagen diseases. Functional images of V, Vol, Q and V/Q ratio were obtained at total lung capacity. Wash-out time was calculated from the wash-out curve. Whole body scans were performed in 65 patients to evaluate intra-pulmonary shunts.
  
  
  RESULTS
  Increased V/Q areas were observed in 74 patients (67.9%), suggesting some impairment of pulmonary perfusion. Decreased perfusion, probably due to vasculitis or intravascular microcoagulation, was observed often, even in patients without pulmonary fibrosis. Shunt ratios over 10% were observed in 8 of the 65 patients (12.3%), indicating formation of PA-PV shunts secondary to peripheral vascular impairment. Wash-out time was prolonged in 37 patients (33.9%), shortened in 18 (16.5%), and within the normal range in 54 (49.6%). The prolonged and normal wash-out times in the patients with pulmonary fibrosis may represent obstructive changes in the small airways superimposed on the fibrosis.
  
  
  CONCLUSIONS
  Ventilation/perfusion scans are a very useful tool for evaluating collagen lung diseases, and they might contribute to treatment decisions for the patients.
authors.affiliation: Department of Radiology, Tokyo Metropolitan Hiro-o Hospital, Japan. fwnb4989@mb.infoweb.ne.jp
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
authors.forename: N
authors.initials: N
authors.lastname: Kamata
authors.forename: S
authors.initials: S
authors.lastname: Inokuma
authors.forename: H
authors.initials: H
authors.lastname: Terada
authors.forename: Y
authors.initials: Y
authors.lastname: Yokoyanma
authors.forename: K
authors.initials: K
authors.lastname: Abi
authors.forename: T
authors.initials: T
authors.lastname: Mochizuki
authors.forename: T
authors.initials: T
authors.lastname: Kobayashi
mesh_terms: D003095:Collagen Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D011658:Pulmonary Fibrosis / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012129:Respiratory Function Tests; D013668:Technetium Tc 99m Aggregated Albumin / Q000493:pharmacokinetics; D014055:Tomography, Emission-Computed; D014692:Ventilation-Perfusion Ratio; D014980:Xenon Radioisotopes / Q000493:pharmacokinetics
chemical_list: D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin; D014980:Xenon Radioisotopes