Clinical significance of ventilation/perfusion scans in collagen disease patients.
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.
Suzuki
K
K
Department of Radiology, Tokyo Metropolitan Hiro-o Hospital, Japan. fwnb4989@mb.infoweb.ne.jp
Kamata
N
N
Inokuma
S
S
Terada
H
H
Yokoyanma
Y
Y
Abi
K
K
Mochizuki
T
T
Kobayashi
T
T
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
D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin; D014980:Xenon Radioisotopes