Emohare Osa, Cagan Amanda, Morgan Robert, Davis Rick, Asis Martin, Switzer Julie, Polly David W
Department of Neurosurgery, Regions Hospital, Saint Paul, MN, USA ; Department of Orthopaedic Surgery, University of Minnesota Medical School, Minneapolis, MN, USA.
Health Partners Institute for Education and Research, Bloomington, MN, USA.
Geriatr Orthop Surg Rehabil. 2014 Jun;5(2):50-5. doi: 10.1177/2151458514525042.
Relatively few patients have dual-energy x-ray absorptiometry to quantify the magnitude of bone loss as they age. Recent work correlates mean computed tomography (CT) attenuation in the level I (L1) vertebra with bone mineral density (BMD), making it possible to objectively evaluate the magnitude of bone loss in osteoporosis by this method. The aims of this study were to evaluate the utility of using CT scans in patients with acute thoracic and lumbar spine fractures to diagnose osteoporosis and using CT attenuation to evaluate the association between age and BMD.
We performed a retrospective study of patients with acute fractures of the thoracic or lumbar spine who had also undergone an abdominal (or L1) CT scan and compared mean CT attenuation in L1 against threshold values. We also compared differences in CT attenuation between younger (<65 years) and older (≥65 years) and older patients.
A total of 124 patients were evaluated (74 thoracic and 50 lumbar fractures). Overall, there was a strong correlation between age and bone density as measured by CT attenuation (r = -.76). Among those with thoracic fractures (<65 years), mean CT attenuation was 196.51 HU. Forty-one patients were ≥65 years and had mean CT attenuation of 105.90 HU (P < .001). In patients with lumbar fractures, 27 patients were <65 years and had a mean CT attenuation of 192.26 HU and 23 patients were ≥65 years and had mean CT attenuation of 114.31 HU (P < .001). At the threshold of 110 HU, set for specificity, the magnitude of difference between the age-stratified cohorts was greater in the thoracic spine (P < .0001 vs P = .003).
Using opportunistic CT, we demonstrate the relative frequency of osteoporosis in patients with acute fractures of the thoracic and lumbar spine and confirm that the association increases with age. The CT attenuation may provide a cheap and convenient method to help confirm a clinical diagnosis of osteoporosis in patients with fractures.
随着年龄增长，相对较少的患者会接受双能X线吸收测定法来量化骨质流失的程度。最近的研究表明，第一腰椎（L1）水平的平均计算机断层扫描（CT）衰减与骨矿物质密度（BMD）相关，这使得通过这种方法客观评估骨质疏松症患者骨质流失的程度成为可能。本研究的目的是评估在急性胸腰椎骨折患者中使用CT扫描诊断骨质疏松症的实用性，并利用CT衰减来评估年龄与BMD之间的关联。
我们对同时接受了腹部（或L1）CT扫描的急性胸腰椎骨折患者进行了一项回顾性研究，并将L1的平均CT衰减与阈值进行比较。我们还比较了年轻（<65岁）和老年（≥65岁）患者之间CT衰减的差异。
共评估了124例患者（74例胸椎骨折和50例腰椎骨折）。总体而言，通过CT衰减测量的年龄与骨密度之间存在很强的相关性（r = -0.76）。在胸椎骨折患者中（<65岁），平均CT衰减为196.51 HU。41例患者年龄≥65岁，平均CT衰减为105.90 HU（P < 0.001）。在腰椎骨折患者中，27例患者年龄<65岁，平均CT衰减为192.26 HU，23例患者年龄≥65岁，平均CT衰减为114.31 HU（P < 0.001）。设定特异性阈值为110 HU时，年龄分层队列之间的差异幅度在胸椎中更大（P < 0.0001 vs P = 0.003）。
通过机会性CT，我们证明了急性胸腰椎骨折患者中骨质疏松症的相对发生率，并证实这种关联随着年龄的增长而增加。CT衰减可能提供一种廉价且方便的方法，有助于在骨折患者中确诊骨质疏松症的临床诊断。
