Published online before print October 24, 2002, 10.1148/radiol.2253011384
Bronchiolitis Obliterans Syndrome in Lung Transplant Recipients: Use of Spirometrically Gated CT1
Friedrich D. Knollmann, MD,
Ralf Ewert, MD,
Tarja Wündrich, MA,
Roland Hetzer, MD, PhD and
Roland Felix, MD, PhD
1 From the Department of Radiology, Charité, Campus Virchow-Klinikum, Humboldt-University, Augustenburger Platz 1, 13353 Berlin, Germany (F.D.K., T.W., R.F.); and Department of Cardiothoracic and Vascular Surgery, German Heart Institute, Berlin, Germany (R.E., R.H.). From the 2001 RSNA scientific assembly. Received August 14, 2001; revision requested October 10; revision received January 9, 2002; accepted February 20. Address correspondence to F.D.K. (e-mail: friedrich.knollmann@charite.de).
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Figure 1. Mean lung attenuation as a function of anatomic section position (levels 1-3) and inspiration (% VC) for patients with persistent normal lung function (white boxes) and patients with BOS 1 year after CT (gray boxes). Level 1 is the area 5 cm above the carina, level 2 is the area at the carina, and level 3 is the area 5 cm below the carina. Mean parenchymal attenuation in patients who would develop BOS within 1 year after CT was significantly lower than that in patients with persistent normal lung function.
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Figure 2a. Spirometrically gated thin-section CT scans obtained in a double lung transplant recipient with normal pulmonary function at the time of the CT examination who had BOS at presentation 1 year later. (a) Inspiratory scan shows homogeneous parenchymal attenuation. Mean parenchymal attenuation was -878 HU. (b) Expiratory scan shows that lung parenchyma remained homogeneous, and parenchymal attenuation was -858 HU. This case illustrates that the absence of visual indicators of small-airway disease does not exclude a progression to BOS within the next year and that parenchymal hyperinflation, as determined by measurements of parenchymal attenuation, may be used to predict the future course of lung function.
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Figure 2b. Spirometrically gated thin-section CT scans obtained in a double lung transplant recipient with normal pulmonary function at the time of the CT examination who had BOS at presentation 1 year later. (a) Inspiratory scan shows homogeneous parenchymal attenuation. Mean parenchymal attenuation was -878 HU. (b) Expiratory scan shows that lung parenchyma remained homogeneous, and parenchymal attenuation was -858 HU. This case illustrates that the absence of visual indicators of small-airway disease does not exclude a progression to BOS within the next year and that parenchymal hyperinflation, as determined by measurements of parenchymal attenuation, may be used to predict the future course of lung function.
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Figure 3. Homogeneity of lung attenuation as a function of anatomic section position (levels 1-3) and inspiratory level (% VC) in patients with persistent normal lung function (white boxes) and in patients with BOS 1 year after CT (gray boxes). Level 1 is the area 5 cm above the carina, level 2 is the area at the carina, and level 3 is the area 5 cm below the carina. In patients who developed BOS within 1 year after CT, a more homogeneous distribution of parenchymal attenuation was displayed than that in patients with persistent normal lung function.
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Figure 4. Time course of lung function at CT (%) and 1 year later (%2). In general, pulmonary function declined with time.
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Figure 5a. Spirometrically gated thin-section CT scans in a recipient of a heart and lung transplant whose pulmonary function was normal at CT and remained normal 1 year later. (a) Inspiratory scan shows homogeneous parenchymal attenuation. Mean attenuation was -778 HU. (b) Expiratory scan shows a patchy pattern of parenchymal attenuation inhomogeneity, which qualified as air trapping. Mean parenchymal attenuation was -717 HU. This case illustrates that the presence of visual signs of small-airway disease at thin-section CT does not necessarily suggest a diagnosis of BOS nor a deterioration of pulmonary function within the next year.
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Figure 5b. Spirometrically gated thin-section CT scans in a recipient of a heart and lung transplant whose pulmonary function was normal at CT and remained normal 1 year later. (a) Inspiratory scan shows homogeneous parenchymal attenuation. Mean attenuation was -778 HU. (b) Expiratory scan shows a patchy pattern of parenchymal attenuation inhomogeneity, which qualified as air trapping. Mean parenchymal attenuation was -717 HU. This case illustrates that the presence of visual signs of small-airway disease at thin-section CT does not necessarily suggest a diagnosis of BOS nor a deterioration of pulmonary function within the next year.
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Figure 6. ROCs for predicting BOS 1 year after CT from spirometrically gated thin-section CT measurements of mean lung attenuation and the SD. The predictive power of mean parenchymal attenuation is superior to that of parenchymal homogeneity in lung transplant recipients. FPF = false-positive fraction, TPF = true-positive fraction (sensitivity).
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Copyright © 2002 by the Radiological Society of North America.
