Trabecular Bone Mean Density, but Not Entropy or Uniformity, May Predict Bone Pain in Acromegalic Patients

Presentation Number: SUN 437
Date of Presentation: April 2nd, 2017

Armindo Jreige Jr., Olga de Castro Dytz, Arthur Disegna, Rhenan Reis, Vitoria Espindola Leite Borges, Pedro de Azevedo Berger and Luciana Ansaneli Naves*
University of Brasilia, Brasilia, Brazil

Abstract

Acromegaly is a chronic systemic disease characterized by exaggerated somatic growth due to the hypersecretion of GH and IGF-1; which are anabolic hormones and regulate the bone formation and remodeling in both trabecular and cortical bones. Their anabolic effects on the cortical bone can mask their negative effects on trabecular bone on conventional DXA exams (1). The limitations of DXA are well known and include: two-dimensional assessment of bone mineral density (BMD) suffering the influence of bone size, inability to distinguish between cortical and trabecular bone and impossibility of quantifying macro and microstructural bone properties that influence the bone strength (2). For allowing the distinction between cortical and trabecular bone, the CT images could be useful in assessing bone health in acromegalic patients. In order to improve the analysis of CT images, we created new software that analyses a designated area in the L1 vertebral body trabecular bone and yields the measures of entropy, uniformity and average density of the designated area (based on Hounsfield units). 33 acromegalic patients were enrolled in the study and underwent lumbosacral CT and DXA. Five patients (15,2%) had a previous history of non-traumatic bone injury and 21 (63.6%) complained of bone pain. Mean L1 BMD was 1,145±0,153g/cm3, and it was found to strongly correlate with L1 trabecular bone mean density (TBMD) from CT images (r=0.625, p<0.001). However, TBMD was significantly reduced in patients who complained of bone pain (p<0.01), but not BMD (p=0.369), entropy (p=0.768) or uniformity (p=0.81). The number of distinct bone abnormalities observed on CT scan did not correlate to BMD (r=-0.341, p=0.089) neither to TBMD (r=-0,377, p=0.058). IGF-I upper limit normal variation values were not found to correlate with TBMD (r=0.22, p=0.234), entropy (r=0.226, p=0.221) or uniformity (r=-0.237, p=0.199). Serum calcium, phosphorus, alkaline phosphatase and PTH levels were also unrelated to TBMD or BMD values. Our study suggests that the measurement of trabecular bone mean density by tomography correlates with DXA measured BMD and could work as an alternative approach for the assessment of bone health in acromegaly, taking into account also the prediction of clinical complains.

 

Nothing to Disclose: AJ Jr., ODCD, AD, RR, VELB, PDAB, LAN