使用水选择性平衡稳态自由进动序列对膝关节软骨进行磁共振成像。

Magnetic resonance imaging of knee cartilage using a water selective balanced steady-state free precession sequence.

作者信息

Kornaat Peter R, Doornbos Joost, van der Molen Aart J, Kloppenburg Margreet, Nelissen Rob G, Hogendoorn Pancras C W, Bloem Johan L

机构信息

Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.

出版信息

J Magn Reson Imaging. 2004 Nov;20(5):850-6. doi: 10.1002/jmri.20194.

DOI:10.1002/jmri.20194

PMID:15503345

Abstract

PURPOSE

To compare an optimized water selective balanced steady-state free precession sequence (WS-bSSFP) with conventional magnetic resonance (MR) sequences in imaging cartilage of osteoarthritic knees.

MATERIALS AND METHODS

Flip angles of sagittal and axial WS-bSSFP sequences were optimized in three volunteers. Subsequently, the knees of 10 patients with generalized osteoarthritis were imaged using sagittal and axial WS-bSSFP and conventional MR imaging techniques. We calculated contrast-to-noise ratios (CNR) between cartilage and its surrounding tissues to quantitatively analyze the various sequences. Using dedicated software we compared, in two other patients, the accuracy of cartilage volume measurements with anatomic sections of the tibial plateau.

RESULTS

CNRtotal eff (CNR efficiency between cartilage and its surrounding tissue) using WS-bSSFP was maximal with a 20-25 degrees flip angle. CNRtotal eff was higher in WS-bSSFP than in conventional images: 6.1 times higher compared to T1-weighted gradient echo (GE) images, 5.1 compared to proton-density (PD) fast spin echo (FSE) images, and 4.8 compared to T2-weighted FSE images. The mean difference of cartilage volume measurement on WS-bSSFP and anatomic sections was 0.06 mL compared to 0.24 mL for T1-GE and anatomic sections.

CONCLUSION

A WS-bSSFP sequence is superior to conventional MR imaging sequences in imaging cartilage of the knee in patients with osteoarthritis.

摘要

目的

比较优化后的水选择性平衡稳态自由进动序列（WS-bSSFP）与传统磁共振（MR）序列在骨关节炎膝关节软骨成像中的效果。

材料与方法

在三名志愿者中对矢状面和横断面的WS-bSSFP序列的翻转角进行优化。随后，对10例广泛性骨关节炎患者的膝关节采用矢状面和横断面的WS-bSSFP序列以及传统MR成像技术进行成像。我们计算软骨与其周围组织之间的对比噪声比（CNR），以定量分析各种序列。在另外两名患者中，使用专用软件将软骨体积测量的准确性与胫骨平台的解剖切片进行比较。

结果

使用WS-bSSFP序列时，在翻转角为20 - 25度时，总有效对比噪声比（软骨与其周围组织之间的对比噪声比效率）最大。WS-bSSFP序列的总有效对比噪声比高于传统图像：与T1加权梯度回波（GE）图像相比高6.1倍，与质子密度（PD）快速自旋回波（FSE）图像相比高5.1倍，与T2加权FSE图像相比高4.8倍。WS-bSSFP序列与解剖切片测量的软骨体积平均差异为0.06 mL，而T1-GE序列与解剖切片测量的平均差异为0.24 mL。