Two new regions of interest to evaluate separately cortical and trabecular BMD in the proximal femur using DXA

Abstract

To differentiate changes in trabecular and cortical bone density at a skeletal site bearing body weight, the main goal of this retrospective study was to develop and characterize two new regions of interest (ROIs) for DXA at the hip, one mainly focusing on trabecular bone and another mainly focusing on cortical bone. Specific aims were to maximize the precision of the ROIs and to characterize their usefulness for monitoring age-related bone loss and discriminating controls from fracture cases in a cross-sectional study population and to compare them with earlier ROIs designed by our group. The study used populations from two different previous studies conducted in our laboratory, with one comprising cohorts of healthy premenopausal women, healthy postmenopausal women, and postmenopausal osteoporotic women with at least one spinal fracture (Spine Fx Study) and the other one comprising two cohorts of age-matched postmenopausal women, in whom cases had sustained a hip fracture (Hip Fx study). The new ROI for trabecular bone (CIRCROI) tries to improve on the earlier custom-designed Central ROI, which was also targeted at trabecular bone. CIRCROI consists of an approximate largest circle that can fit inside the femoral proximal metaphysis without touching the superior and inferior endocortical walls. The new ROI for cortical bone (CORTROI) at a site bearing body weight is defined as a horizontal rectangular box crossing the femoral shaft below the lesser trochanter. CORTROI BMD cohort means were significantly higher than all other ROIs, and CIRCROI BMD cohort means were lower than standard ROIs with the exception of Ward's ROI. CIRCROI BMD was highly correlated with total femur BMD ( r=0.94) and Central BMD ( r=0.93), whereas CORTROI BMD correlations were lower (highest with total femur BMD ( r=0.86)). Fracture discrimination odds ratios (ORs) of all ROIs were significant for the Hip Fx Study, with CIRCROI BMD having the highest, and CORTROI BMD the lowest, OR (4.83 and 2.49 per SD, respectively, compared with 3.69 for Ward's ROI as the highest OR of standard ROIs). For the Spine Fx Study, only spinal and trochanteric BMD had significant OR. The new trabecular ROI had good short-term precision, comparable to the standard ROIs at the hip, but improving on that of Ward's triangle, the only standard ROI only including the anterior and posterior cortical walls and therefore more predominantly consisting of trabecular bone than other standard ROIs. The precision of the new cortical ROI was lower than standard DXA ROIs, except for Ward's triangle, but provides unique information on purely cortical bone at a skeletal site bearing body weight.

Effects of short‐term alendronate on bone mineral density in haemodialysis patients

“…24 The DEXA evaluation at this site appears to have less reproducibility than at other sites in the hip. 25 There is a higher percentage of trabecular bone in this region (compared with other regions within the hip), which may account for this phenomenon. As such, any observed changes in BMD at Ward's Triangle might not reflect true changes in cortical bone.…”

“…Recently, the International Society of Clinical Densitometry recommended that BMD at this sight not be used to diagnose osteoporosis 24 . The DEXA evaluation at this site appears to have less reproducibility than at other sites in the hip 25 . There is a higher percentage of trabecular bone in this region (compared with other regions within the hip), which may account for this phenomenon.…”

Assessment of the bilateral asymmetry of human femurs based on physical, densitometric, and structural rigidity characteristics

“…Such a precise registration scheme is impossible in the clinical setting. However, improvements in post-image processing, advancements in macro-and microstructure imaging (Rubin et al, 1992), and novel and comprehensive DXA ROI’s (Takada et al, 1997; Prevrhal et al, 2004) will aid in registration and analysis. While data on limb dominance, recent and accumulated activity level prior to death, and past medical history may have affected the loading pattern of the femur would have been interesting covariates, this data was not available to us.…”

Bone loss with antiepileptic drug therapy: a twin and sibling study

“…Assessment of the potential effectiveness of antiresorptive therapy, vitamin D and calcium supplementation, either separately or in combination, for ameliorating any adverse longitudinal effects of AEDs on bone would be worthwhile. Also, use of newer scanning technology to allow micro-architectural indices to be measured, focusing separately on trabecular and cortical bone parameters [37] may better quantify bone strength and predict fracture risk in AED users.…”