Postmenopausal women with osteopenia have higher cortical porosity and thinner cortices at the distal radius and tibia than women with normal aBMD: An in vivo HR-pQCT study

Abstract

Increases in cortical porosity (Ct.Po) and decreases in cortical thickness (Ct.Th) are associated with increased bone fragility. The purpose of this study was to validate an autosegmentation method for high-resolution peripheral quantitative computed tomography (HR-pQCT) scans to measure Ct.Po and Ct.Th and use it to compare Ct.Po and Ct.Th between pre-and postmenopausal women with normal, osteopenic, and osteoporotic areal bone mineral density (aBMD). The Ct.Po and Ct.Th measurements were validated using cadaver forearms (n ¼ 10) and micro-computed tomography (mCT) as the gold standard. The analysis was applied to distal radius and tibia HRpQCT scans from a subset of participants from the Calgary, Alberta, cohort of the Canadian Multicentre Osteoporosis Study (n ¼ 280, 18 to 90 years). Analysis of covariance compared Ct.Po and Ct.Th outcomes between 63 normal premenopausal (dual-energy X-ray absorptiometry femoral neck T-score > À1), 87 normal postmenopausal, 121 osteopenic postmenopausal, and 9 osteoporotic postmenopausal women. Linear regression analysis and Bland-Altman plots were used to assess the agreement between the HRpQCT and mCT measurements, resulting in r 2 values of 0.80 for Ct.Po and 0.98 for Ct.Th. At both sites, Ct.Po was higher in postmenopausal (all groups) than in premenopausal women (3.2% to 12.9%, p < .001). Ct.Th was not significantly different between normal premenopausal and postmenopausal women at either site; however, both osteopenic and osteoporotic women had thinner (À12.8% to À30.3%, p < .01), more porous (2.1% to 8.1%, p < .001) cortices than normal postmenopausal women. Our method offers promise as a valuable tool to measure Ct.Po and Ct.Th in vivo and investigate associations among cortical bone structure, age, and disease status. ß

Compromised trabecular microarchitecture and lower finite element estimates of radius and tibia bone strength in adults with turner syndrome: A cross-sectional study using high-resolution–pQCT

“…However, no evidence of cortical bone deficits in TS patients was found in our study. Also, differences in HR-pQCT and pQCT methodologies may be of importance, as cortical thickness in the HR-pQCT methodology applied here was a 3D measure of the periosteal-endosteal distance, (26) whereas cortical thickness in pQCT studies (18,19) was derived mathematically, assuming that the radius crosssection is circularly shaped (37) ; an assumption that may be challenged, perhaps especially in TS individuals. Also, measurement of cortical vBMD by pQCT is influenced by cortical thickness, due to partial volume artifacts, resulting in falsely low values in thin compared to thicker cortices.…”

“…In addition, specific cortical evaluation software was applied allowing for a direct 3D measure of cortical thickness (periosteal-endosteal distance) along with a measure of intracortical porosity (percent void cortical volume/total cortical volume). (25,26) To account for differences in body size between TS and controls, with TS participants being shorter than controls, an additional analysis of geometry, vBMD, cortical and trabecular microarchitecture was performed using a height-matched regions of interest (ROI). With the default image acquisition protocol, the ROI in TS participants had a mean starting position of 0.64% and 1.51% relative to body height, at the radius and tibia, respectively (similar numbers in controls were 0.58% and 1.35%).…”

Parathyroidectomy improves bone geometry and microarchitecture in female patients with primary hyperparathyroidism: A one-year prospective controlled study using high-resolution peripheral quantitative computed tomography

“…An automatic cortical bone analysis based on a dual threshold approach was applied, (21,22,26) providing a direct 3D measure of cortical thickness (the endosteal-periosteal distance) along with measures of intracortical porosity (percent void volume/total cortical volume) and mean cortical pore diameter.…”

“…This is most likely caused by the inability of HR-pQCT system to capture small cortical pores adequately. (21) A substantial fraction of porosity will then be missed because a large portion of pores are below 100 mm, at least in postmenopausal women. (34) In patients, radius cancellous architecture was enhanced in response to surgery, with significant increases in trabecular number and decreases in trabecular spacing.…”

“…High-resolution peripheral quantitative computed tomography (HR-pQCT) allows in vivo characterization of bone geometry, volumetric bone mineral density (vBMD), microarchitecture, and estimated bone strength at the distal radius and tibia. (20)(21)(22)(23) This technique is evolving as a promising clinical tool in bone structure evaluation, offering insights into the skeletal pathophysiology of bone metabolic diseases. We have previously reported negative effects on both cortical and trabecular bone compartments in radius but not in tibia in female patients with PHPT using HR-pQCT.…”