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 densityin 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.