Diffusion tensor imaging and magnetic resonance spectroscopy assessment of cancellous bone quality in femoral neck of healthy, osteopenic and osteoporotic subjects at 3T: Preliminary experience
Diffusion tensor imaging and magnetic resonance spectroscopy assessment of cancellous bone quality in femoral neck of healthy, osteopenic and osteoporotic subjects at 3T: Preliminary experience
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DOI：
10.1016/j.bone.2013.03.004
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发表时间：
2013-07-01
期刊：
影响因子：
4.1
通讯作者：
Simonetti, Giovanni
中科院分区：
文献类型：
--
作者：
Manenti, Guglielmo;Capuani, Silvia;Simonetti, Giovanni
我们评估了扩散张量成像（DTI）结合质子磁共振波谱（H-1-MRS）在绝经后妇女股骨颈松质骨质量评估中的潜力。DTI允许非侵入性的异质组织的微结构表征。在这项工作中，我们假设DTI参数的平均扩散率（MD）和分数各向异性（FA）骨髓水，可以提供信息发生骨质疏松症的微观结构的变化。由于骨质疏松症与骨髓脂肪含量增加有关，这在原则上可以改变DTI参数，因此本研究的目的是研究MD和FA结合骨髓脂肪分数（FF）的潜力，以区分健康、骨质减少和骨质疏松的受试者，并根据DXA标准进行分类。材料和方法：40例绝经后妇女（平均年龄68.7岁，52-81岁）行股骨颈双能x线吸收仪（DXA）检查，分为健康（n = 12）、骨质减少（n = 14）和骨质疏松（n = 14）。在3T时，获得每位受试者股骨颈的H-1-MRS和DTI （b值= 2500 s/mm(2)）。本研究方案经当地伦理委员会批准。测定3个骨密度组的MD、FA、FF和MD/FF、FA/FF，并进行比较。采用Bonferroni检验和Pearson相关分析。并进行受试者工作特征（ROC）曲线分析。结果：DTI测量的重现性令人满意。MD的CV约为2%-3%，FA的CV约为4%-5%。此外，在由6名健康志愿者组成的两个单独的疗程（中间间隔34天）中，MD和FA测量没有发现显著差异。FF仅能区分健康受试者和骨质疏松受试者。相反，MD和FA能够区分健康与骨质减少和健康与骨质疏松的受试者，但它们不能区分骨质减少和骨质疏松的患者。仅在健康组中，MD与FF之间存在显著相关性。当所有组一起考虑时，发现MD与T-score之间存在中等相关性。组内MD与T-score无显著相关。在骨质减少组和骨质疏松组中，FA和FF均呈显著正相关。反之，健康组FA与FF无相关性。FA与t评分在所有组、健康组和骨质疏松组均呈显著正相关。与MD和FA相比，MD/FF和FA/FF在区分健康和骨质疏松患者方面具有更高的敏感性和特异性。从股骨颈提取MD/FF vs FA/FF图，根据DXA结果识别所有健康个体。结论：股骨颈DTI-H-1-MRS方案在识别健康受试者方面具有很高的敏感性和特异性。与DXA检查相比，MR检查更昂贵。然而，尽管DXA骨密度评估已成为公认的骨质疏松症诊断标准，但DXA结果对患者未来骨折风险的预测价值较低。因此，对有骨质疏松风险的患者进行检查的新方法将是可取的。本文显示的初步结果表明，未来基于股骨颈DTI评估的更大人群研究，结合H-1-MRS调查，可能允许筛查高危人群和建立正常的临界值，并可能将该方法应用于单个受试者。(C) 2013爱思唯尔公司版权所有。
We assessed the potential of diffusion tensor imaging (DTI) in combination with proton magnetic resonance spectroscopy (H-1-MRS), in cancellous bone quality evaluation of the femoral neck in postmenopausal women. Introduction: DTI allows for non-invasive microarchitectural characterization of heterogeneous tissue. In this work we hypothesized that DTI parameters mean diffusivity (MD) and fractional anisotropy (FA) of bone marrow water, can provide information about microstructural changes that occur with the development of osteoporosis disease. Because osteoporosis is associated with increased bone marrow fat content, which in principal can alter DTI parameters, the goal of this study was to examine the potential of MD and FA, in combination with bone marrow fat fraction (FF), to discriminate between healthy, osteopenic and osteoporotic subjects, classified according to DXA criteria.Materials and methods: Forty postmenopausal women (mean age, 68.7 years; range 52-81 years), underwent a Dual-energy X-ray absorptiometry (DXA) examination in femoral neck, to be classified as healthy (n = 12), osteopenic (n = 14) and osteoporotic (n = 14) subjects. H-1-MRS and DTI (with b value = 2500 s/mm(2)) of femoral neck were obtained in each subject at 3T. The study protocol was approved by local Ethics Committee. MD, FA, FF and MD/FF, FA/FF were obtained and compared among the three bone-density groups.One-way ANOVA with multiple comparisons Bonferroni test and Pearson correlation analysis were applied. Receiver operating characteristic (ROC) curve analysis was also performed.Results: Reproducibility of DTI measures was satisfactory. CV was approximately 2%-3% for MD and 4%-5% for FA measurements. Moreover, no significant difference was found in both MD and FA measurements between two separate sessions (median 34 days apart) comprised of six healthy volunteers.FF was able to discriminate between healthy and osteoporotic subjects only. Conversely MD and FA were able to discriminate healthy from osteopenic and healthy from osteoporotic subjects, but they were not able to discriminate between osteopenic and osteoporotic patients. A significant correlation between MD and FF was observed in healthy group only. A moderate correlation was found between MD and T-score when all groups together are considered. No significant correlation was found between MD and T-score within groups. A significant positive correlation between FA and FF was found in both osteopenic and osteoporotic groups. Vice-versa no correlation between FA and FF was observed in healthy group. A high significant positive correlation was found between FA and T-score in all groups together, in healthy and in osteoporotic groups. MD/FF and FA/FF are characterized by a higher sensitivity and specificity compared to MD and FA in the discrimination between healthy, and osteoporotic subjects.MD/FF vs FA/FF graph extracted from femoral neck, identify all healthy individuals according to DXA results.Conclusion: DTI-H-1-MRS protocol performed in femoral neck seems to be highly sensitive and specific in identifying healthy subjects.A MR exam is more expensive when compared to a DXA investigation. However, even though DXA BMD evaluation has been the accepted standard for osteoporosis diagnosis, DXA result has a low predictive value on patients' risk for future fractures. Thus, new approaches for examining patients at risk for developing osteoporosis would be desirable.Preliminary results showed here suggest that future studies on a larger population based on DTI assessment in the femoral neck, in combination with H-1-MRS investigations, might allow screening of high-risk populations and the establishment of cut-off values of normality, with potential application of the method to single subjects. (C) 2013 Elsevier Inc. All rights reserved.