Bone attenuation on chest computed tomography correlates with bone mineral density on densitometry in patients with emphysema and COPD

Introduction: Patients with chronic obstructive pulmonary disease (COPD) have an increased risk of osteoporosis. In these patients, the relationship between osteoporosis measured by bone density in chest computed tomography (CT) and dual-energy X-ray absorptiometry (DXA) is not well established. Objectives: To determine the association between the bone mineral density (BMD) measured in the first lumbar vertebra (L1) of a low dose chest CT (LDCT) with the one measured in a bone DXA. We also aim at exploring the possible association of this measurement with the severity of radiological emphysema. Methods: 43 COPD patients with emphysema were evaluated. In a LDCT we determined BMD in the central part of L1 body. DXA was in all patients. The quantification of emphysema in CT was performed using a specific software (Volume, Siemens Healthcar) considering 3 different thresholds: -900, -950 and -960 Hounsfield Units (HU), and the emphysema index (EI) was calculated. Spearman correlation coefficient was used for the statistical analysis. Results: The correlation between the BMD in L1 by CT and the lumbar spine (L1-L4) density by DXA was 0.40 (p Conclusions: There is a weak correlation between BMD measured in CT and DXA. In the same way, there is a weak inverse correlation between IE and BMD determined by CT. Further studies are needed to establish the relationship between these two diseases processes.