Elisabeth Romme, Presenter: Nothing to Disclose

John Murchison MBCHB, Abstract Co-Author: Speaker, Toshiba Corporation

K.F. Phang, Abstract Co-Author: Nothing to Disclose

F.H. Jansen, Abstract Co-Author: Nothing to Disclose

E.P.A. Rutten, Abstract Co-Author: Nothing to Disclose

E.F.M. Wouters, Abstract Co-Author: Nothing to Disclose

F W J M Smeenk, Abstract Co-Author: Nothing to Disclose

Edwin J R Van Beek MD, PhD, Abstract Co-Author: Research support, Toshiba Corporation Research support, Siemens AG Founder and owner, QCTIS, Inc Speaker, Toshiba Corporation Speaker, Vital Images Inc

William MacNee MD, PhD, Abstract Co-Author: Advisory Board, Pfizer Inc Advisory Board, Almirall SA Advisory Board, Johnson & Johnson Speaker, GlaxoSmithKline plc Speaker, Boehringer Ingelheim GmbH Speaker, Novartis AG

Osteoporosis is a well recognised extra pulmonary effect of COPD that can contribute to the severity of the disease. Routine chest CT is increasingly used to assess the extent of emphysema and airways disease in patients with COPD. We investigated whether simple attenuation measurement of the thoracic spine on routine chest CT may provide useful information on bone health in patients with COPD.

Fifty-eight patients (62% males, aged 65.9±8.0 years and FEV1 % predicted 59.7±15.2) with moderate to very severe COPD who had undergone both chest CT and dual-energy X-ray absorptiometry (DXA) were included. The mean attenuation of thoracic vertebrae 4, 7 and 10 on chest CT was determined by placing circular regions of interest (ROIs) using different area measurements (50 mm2, 100 mm2 and 200 mm2) in the central parts of the vertebral bodies. The average attenuation of the three thoracic vertebrae was correlated with the lowest bone mineral density (BMD) of the hip and lumbar spine (L1 to L4) on DXA.

The intra class correlation coefficients between the ROIs using different area measurements were high (r≥0.99, p<0.001).The inter and intra-observer variabilities of the attenuation measurements were low as shown by Bland Altman plots. Pearson’s correlation coefficient between the average attenuation of the three thoracic vertebrae and the lowest BMD of the hip and lumbar spine was high (r=0.827, p<0.001). A ROC analysis of the area under the curve for osteoporosis was 0.969 (p<0.001) corresponding to an attenuation threshold of 147 Hounsfield Units.

Our study showed that bone attenuation measured on routine chest CT correlated strongly with BMD assessed on DXA in patients with COPD. Routine chest CT may provide useful information on bone health in patients with COPD.

Our data suggest that chest CT might be used for osteoporosis screening in patients with COPD. However, more research is warranted in larger populations and using different scanners.

Romme, E, Murchison, J, Phang, K, Jansen, F, Rutten, E, Wouters, E, Smeenk, F, Van Beek, E, MacNee, W, Bone Attenuation on Routine Chest CT Correlates with Bone Mineral Density on DXA in Patients with COPD.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12028272.html