扫频成像傅里叶变换在马动物模型中对软骨-骨修复的评估。

Osteochondral repair: evaluation with sweep imaging with fourier transform in an equine model.

机构信息

Department of Applied Physics, A. I. Virtanen Institute for Molecular Sciences, and Institute of Biomedicine, Anatomy, University of Eastern Finland, PO Box 1627, 70211 Kuopio, Finland; Department of Equine Sciences, Faculty of Veterinary Medicine, University of Utrecht, Utrecht, the Netherlands; Department of Veterinary Clinical Sciences, School of Veterinary Medicine, University College Dublin, Dublin, Ireland; Center for Magnetic Resonance Research, Departments of Radiology and Orthopaedic Surgery, University of Minnesota, Minneapolis, Minn; Department of Orthopaedics and Traumatology, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland; Department of Orthopaedics and Traumatology, Jyväskylä Central Hospital, Jyväskylä, Finland; Department of Diagnostic Radiology, Institute of Diagnostics, University of Oulu, Oulu, Finland; Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland.

出版信息

Radiology. 2013 Oct;269(1):113-21. doi: 10.1148/radiol.13121433. Epub 2013 May 14.

DOI:10.1148/radiol.13121433

PMID:23674789

Abstract

PURPOSE

To evaluate the status of articular cartilage and bone in an equine model of spontaneous repair by using the sweep imaging with Fourier transform (SWIFT) magnetic resonance (MR) imaging technique.

MATERIALS AND METHODS

Experiments were approved by the Utrecht University Animal Ethics Committee. Six-millimeter-diameter chondral (n = 5) and osteochondral (n = 5, 3-4 mm deep into subchondral bone) defects were created in the intercarpal joints of seven 2-year-old horses and examined with SWIFT at 9.4 T after spontaneous healing for 12 months. Conventional T2 maps and gradient-echo images were obtained for comparison, and histologic assessment of cartilage and micro-computed tomography (CT) of bone were performed for reference. Signal-to-noise ratio (SNR) analysis was performed, and a radiologist evaluated the MR images. Structural bone parameters were derived from SWIFT and micro-CT datasets. Significance of differences was investigated with the Wilcoxon signed rank test and Pearson correlation analysis.

RESULTS

SWIFT was able to depict the different outcomes of spontaneous healing of focal chondral versus osteochondral defects. SWIFT produced constant signal intensity throughout cartilage, whereas T2 mapping showed elevated T2 values (P = .06) in repair tissue (mean T2 in superficial region of interest in an osteochondral lesion = 50.0 msec ± 10.2) in comparison to adjacent intact cartilage (mean T2 = 32.7 msec ± 4.2). The relative SNR in the subchondral plate with SWIFT (0.91) was more than four times higher than that with conventional fast spin-echo (0.12) and gradient-echo (0.19) MR imaging. The correlation between bone volume-to-tissue volume fractions determined with SWIFT and micro-CT was significant (r = 0.83, P < .01).

CONCLUSION

SWIFT enabled assessment of spontaneous osteochondral repair in an equine model.

摘要

目的

利用傅里叶变换扫频成像（SWIFT）磁共振（MR）成像技术评估自发性修复的马模型中的关节软骨和骨的状态。

材料与方法

本实验获得了乌得勒支大学动物伦理委员会的批准。在 7 匹 2 岁的马的腕关节中创建了 6 毫米直径的软骨（n = 5）和骨软骨（n = 5，深入软骨下骨 3-4 毫米）缺损，并在自发愈合 12 个月后在 9.4 T 下使用 SWIFT 进行检查。同时获得了常规 T2 图谱和梯度回波图像进行比较，并进行了软骨的组织学评估和骨的微计算机断层扫描（CT）参考。进行了信噪比（SNR）分析，并由放射科医师评估了 MR 图像。从 SWIFT 和微 CT 数据集导出了结构骨参数。使用 Wilcoxon 符号秩检验和 Pearson 相关分析来研究差异的显著性。

结果

SWIFT 能够描绘出局灶性软骨与骨软骨自发性愈合的不同结果。SWIFT 在整个软骨中产生恒定的信号强度，而 T2 映射显示修复组织中的 T2 值升高（P =.06）（骨软骨病变的表面感兴趣区域的平均 T2 值为 50.0 msec ± 10.2）与相邻完整软骨（平均 T2 = 32.7 msec ± 4.2）相比。SWIFT 的软骨下板的相对 SNR（0.91）比常规快速自旋回波（0.12）和梯度回波（0.19）MR 成像高四倍以上。SWIFT 和微 CT 确定的骨体积与组织体积分数之间的相关性具有显著性（r = 0.83，P <.01）。