Introduction

Age-related loss of bone density is a characteristic of osteoporosis, leading to reduced bone strength and increased risk of fracture. In spine surgery patients, osteoporosis also leads to poor outcomes, including pedicle screw loosening, proximal junctional failure, cage subsidence, and adjacent segment disease. Osteoporosis screening is generally performed using dual energy X-ray absorptiometry (DXA) to assess bone density. Cone beam computed tomography (CBCT) is widely used in orthopedic surgeries, including spine surgeries, and in dental and maxillofacial surgery to visualize teeth and jaws for pathology, surgical planning for jaw and TMJ joint reconstruction, structural maxillofacial deformity, pre-operative implant site assessment, 3D cephalometry, and appropriate treatment planning. CBCT is also used for evaluation of cervical vertebrae in skeletal maturation - growth assessment, diagnosis of obstructive sleep apnea, and temporomandibular disorders. In comparison to traditional computed tomography (CT), CBCT introduces several advantages including high spatial resolution (favorable for bone architecture evaluation); high image accuracy; low cost, faster scan time, ease of use, compact machinery, and low radiation exposure. Few studies have investigated the potential use of CBCT images for opportunistic assessment of bone health as an alternative to traditional CT and DXA. This study investigates whether bone density in the C3 vertebrae as determined by CBCT image analysis aligns with previously known trends of age-related bone loss in women post-menopause. Specifically, this study examines changes in bone density of the C3 vertebrae in females, beginning from puberty to post-menopause to late adulthood. Since the use of CBCT beyond dentistry is not well-established, the overarching goal of this study is to provide support for the reliability of dental CBCT images in the determination of bone health for orthopedic applications.

Objectives

This study aims to provide support for the reliability of cone beam CT in allowing for measurements of bone density. The use of CBCT for opportunistic screening of osteoporosis and potentially orthopedic surgeries is highly relevant for medical and dental professionals. The various advantages of CBCT, including high accuracy, low costs, and greater convenience strengthens its position as a potential alternative to traditional CT. Also, as a result of longer life expectancies, more osteoporotic patients are visiting dental clinics, and existing CBCT scans could be utilized to assess osteoporosis risk.

Methods

Cone beam scans of 416 female patients with ages ranging from 10 to 93 years were obtained between 2010 - 2019. CBCT scans included visualization of the patient's skull, jaw, facial bones, and upper portion of the cervical spine. Sagittal views of the scans were analyzed, with a specific focus on the C3 vertebrae. ImageJ analysis was used to quantify the intensity of the C3 vertebrae region of interest, as a measure of bone density after calibration. Intensity of the muscle area adjacent to the C3 vertebrae and intensity of air in the lungs were measured for the internal calibration of CT Hounsfield units (HU). A linear and spline lines of fit showing changes in bone density values as a function of age were generated to display the overall decline in bone density in females. The linear lines of fit, confidence intervals, linear equations, and R values were calculated using JMP statistical software based on measurements retrieved from the 416 patient scans.

Results

A decline in bone density with age was observed (-2.83 HU/year, p< 0.0001). A rapid decline was observed after 50 years of age (-3.72 HU/year, p=0.0001). These findings are consistent with previously established trends depicting changes in BMD as a function of age in females, such that peak loss of bone density occurs during the first few year's post-menopause, beginning around ages 50 to 54.

Conclusions

The finding that female subjects aged 50-93 years exhibited a significant decrease in bone density is in line with scientific literature exploring the increased prevalence of osteoporosis in postmenopausal women. The ability to identify these established trends using CBCT scans provides evidence for the utility of obtaining bone density measurements through CBCT image analysis. Our findings may be useful in providing evidence in support of CBCT scans as an alternative method of osteoporosis screening and assessment of bone quality in orthopedic and dental surgery patients. Notable limitations of the present study include the exclusion of body mass index (BMI) and race, among other demographic information. Further efforts to obtain this demographic information would be crucial in developing a more complete understanding of our sample data.

中文翻译：

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颈椎骨密度的锥形束计算机断层扫描评估

介绍

与年龄相关的骨密度损失是骨质疏松症的一个特征，会导致骨强度降低和骨折风险增加。在脊柱手术患者中，骨质疏松症也会导致不良预后，包括椎弓根螺钉松动、近端连接失败、融合器下沉和邻近节段疾病。骨质疏松症筛查通常使用双能 X 射线骨密度仪 (DXA) 来评估骨密度。锥形束计算机断层扫描 (CBCT) 广泛用于骨科手术，包括脊柱手术，以及牙科和颌面外科手术，以可视化牙齿和颌骨以进行病理检查、颌骨和 TMJ 关节重建的手术计划、颌面结构畸形、术前植入部位评估、3D 头影测量和适当的治疗计划。CBCT 还用于评估颈椎骨骼成熟 - 生长评估、阻塞性睡眠呼吸暂停的诊断和颞下颌关节紊乱。与传统计算机断层扫描 (CT) 相比，CBCT 引入了几个优点，包括高空间分辨率（有利于骨骼结构评估）；图像精度高；低成本、更快的扫描时间、易用性、紧凑的机器和低辐射暴露。很少有研究调查了将 CBCT 图像作为传统 CT 和 DXA 的替代方案用于对骨骼健康进行机会性评估的潜在用途。本研究调查通过 CBCT 图像分析确定的 C3 椎骨中的骨密度是否与先前已知的绝经后女性年龄相关性骨丢失趋势一致。具体来说，这项研究检查了女性 C3 椎骨骨密度的变化，从青春期到绝经后到成年后期。由于 CBCT 在牙科以外的应用尚未得到充分确立，本研究的首要目标是为牙科 CBCT 图像在确定骨科应用中的骨骼健康方面的可靠性提供支持。

目标

本研究旨在为锥形束 CT 在测量骨密度方面的可靠性提供支持。使用 CBCT 对骨质疏松症和潜在的骨科手术进行机会性筛查与医疗和牙科专业人员高度相关。CBCT 的各种优势，包括高精度、低成本和更大的便利性，巩固了其作为传统 CT 潜在替代品的地位。此外，由于预期寿命延长，越来越多的骨质疏松症患者到牙科诊所就诊，现有的 CBCT 扫描可用于评估骨质疏松症风险。

方法

在 2010 年至 2019 年期间，对 416 名年龄在 10 至 93 岁之间的女性患者进行了锥形束扫描。CBCT 扫描包括对患者头骨、下颌、面部骨骼和颈椎上部的可视化。分析了扫描的矢状视图，特别关注 C3 椎骨。ImageJ 分析用于量化感兴趣的 C3 椎骨区域的强度，作为校准后骨密度的量度。测量与 C3 椎骨相邻的肌肉区域的强度和肺部空气的强度，用于 CT Hounsfield 单位 (HU) 的内部校准。生成显示骨密度值随年龄变化的线性和样条拟合线，以显示女性骨密度的整体下降。线性拟合线、置信区间、线性方程、

结果

观察到骨密度随着年龄的增长而下降（-2.83 HU/年，p<0.0001）。50 岁后观察到快速下降（-3.72 HU/年，p=0.0001）。这些发现与先前确定的描述 BMD 随年龄变化的女性趋势一致，因此骨密度的峰值损失发生在绝经后的最初几年，从 50 到 54 岁左右开始。

结论

50-93 岁女性受试者骨密度显着下降的发现与探索绝经后妇女骨质疏松症患病率增加的科学文献一致。使用 CBCT 扫描识别这些既定趋势的能力为通过 CBCT 图像分析获得骨密度测量值的实用性提供了证据。我们的研究结果可能有助于提供证据支持 CBCT 扫描作为骨科和牙科手术患者骨质疏松症筛查和骨质量评估的替代方法。本研究的显着局限性包括排除体重指数 (BMI) 和种族，以及其他人口统计信息。进一步努力获取这些人口统计信息对于更全面地了解我们的样本数据至关重要。