Watanabe Atsuya, Wada Yuichi, Obata Takayuki, Ueda Takuya, Tamura Mitsuru, Ikehira Hiroo, Moriya Hideshige
Departments of Orthopaedic Surgery and Radiology, Graduate School of Medicine, Chiba University, Chiba, Japan.
Radiology. 2006 Apr;239(1):201-8. doi: 10.1148/radiol.2383050173. Epub 2006 Feb 16.
To prospectively evaluate delayed gadolinium-enhanced magnetic resonance (MR) imaging of cartilage for assessment of glycosaminoglycan (GAG) concentration in reparative cartilage after autologous chondrocyte implantation (ACI).
The study was approved by the ethics review committee of the National Institute of Radiological Sciences, and informed consent was obtained from all patients. The study group comprised nine knees of nine patients (six male, three female; mean age at ACI, 21.2 years +/- 7.5 [standard deviation]; age range, 13-35 years) who had undergone ACI and second-look arthroscopy with biopsy. MR imaging was performed at 1.5 T before and after intravenous injection of anionic gadopentetate dimeglumine. The precontrast R1 (R1(pre)), postcontrast R1 (R1(post)), and difference between R1(pre) and R1(post) (DeltaR1) were measured in reparative cartilage and normal cartilage. GAG concentrations in cartilage biopsy specimens were measured by using high-performance liquid chromatography. To evaluate delayed gadolinium-enhanced MR imaging of cartilage for assessment of GAG concentration, the authors defined the relative R1(pre), relative R1(post), and relative DeltaR1 (ie, R1(pre), R1(post), or DeltaR1, respectively, in reparative cartilage divided by that in normal cartilage) and the relative GAG concentration (ie, GAG concentration in reparative cartilage divided by that in normal cartilage). They then examined the relationships between relative R1(pre), relative R1(post), relative DeltaR1, and relative GAG by using correlation analysis.
A significant correlation between relative DeltaR1 and relative GAG concentration (r = 0.818, P < .05) was observed. However, no significant correlation between relative R1(pre) and relative GAG concentration (r = 0.010, P = .983) or between relative R1(post) and relative GAG concentration (r = 0.660, P = .106) was observed.
Study results indicate that pre- and postcontrast imaging is necessary for delayed gadolinium-enhanced MR imaging evaluation of reparative cartilage after ACI.
前瞻性评估延迟钆增强磁共振（MR）成像对自体软骨细胞植入（ACI）后修复软骨中糖胺聚糖（GAG）浓度的评估价值。
本研究经日本国立放射科学研究所伦理审查委员会批准，并获得所有患者的知情同意。研究组包括9例患者的9个膝关节（男性6例，女性3例；ACI时平均年龄21.2岁±7.5[标准差]；年龄范围13 - 35岁），这些患者均接受了ACI及二次关节镜检查并取活检。在静脉注射阴离子钆喷酸葡胺前后行1.5T MR成像。测量修复软骨和正常软骨的对比前R1（R1(pre)）、对比后R1（R1(post)）以及R1(pre)与R1(post)之间的差值（ΔR1）。采用高效液相色谱法测量软骨活检标本中的GAG浓度。为评估延迟钆增强MR成像对GAG浓度的评估价值，作者定义了相对R1(pre)、相对R1(post)和相对ΔR1（即修复软骨中的R1(pre)、R1(post)或ΔR1分别除以正常软骨中的相应值）以及相对GAG浓度（即修复软骨中的GAG浓度除以正常软骨中的GAG浓度）。然后通过相关性分析研究相对R1(pre)、相对R1(post)、相对ΔR1与相对GAG之间的关系。
观察到相对ΔR1与相对GAG浓度之间存在显著相关性（r = 0.818，P <.05）。然而，未观察到相对R1(pre)与相对GAG浓度之间存在显著相关性（r = 0.010，P =.983），也未观察到相对R1(post)与相对GAG浓度之间存在显著相关性（r = 0.660，P =.106）。
研究结果表明，对于ACI后修复软骨的延迟钆增强MR成像评估，对比前和对比后成像均是必要的。
