发育性髋关节发育不良的 dGEMRIC、T1p 和 T2* 定量 MRI 软骨成像技术之间有何相关性？
What Is the Correlation Among dGEMRIC, T1p, and T2* Quantitative MRI Cartilage Mapping Techniques in Developmental Hip Dysplasia?
机构信息
G. Melkus, K. S. Rakhra, Department of Medical Imaging, The Ottawa Hospital, Ottawa, ON, Canada.
G. Melkus, K. S. Rakhra, Department of Radiology, University of Ottawa, Ottawa, ON, Canada.
出版信息
Clin Orthop Relat Res. 2021 May 1;479(5):1016-1024. doi: 10.1097/CORR.0000000000001600.
BACKGROUND
Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is a validated technique for evaluating cartilage health in developmental dysplasia of the hip (DDH), which can be a helpful prognosticator for the response to surgical treatments. dGEMRIC requires intravenous injection of gadolinium contrast, however, which adds time, expense, and possible adverse reactions to the imaging procedure. Newer MRI cartilage mapping techniques such as T1 rho (ρ) and T2* have been performed in the hip without the need for any contrast, although it is unknown whether they are equivalent to dGEMRIC.
QUESTION/PURPOSE: In this study, our purpose was to determine the correlation between the relaxation values of three cartilage mapping techniques, dGEMRIC, T1ρ, and T2*, in patients with DDH.
METHODS
Fifteen patients with DDH (three male, 12 female; mean age 29 ± 9 years) scheduled for periacetabular osteotomy underwent preoperative dGEMRIC, T1ρ, and T2* MRI at 3T with quantitative cartilage mapping. The outcomes of dGEMRIC, T1ρ, and T2* mapping were calculated for three regions of interest (ROI) to analyze the weightbearing cartilage of the hip: global ROI, anterior and posterior ROI, and further subdivided into medial, intermediate, and lateral to generate six smaller ROIs. The correlation between the respective relaxation time values was evaluated using the Spearman correlation coefficient (rS) for each ROI, categorized as negligible, weak, moderate, strong, or very strong. The relaxation values within the subdivided ROIs were compared for each of the three cartilage mapping techniques using the Kruskal-Wallis test.
RESULTS
There was a moderate correlation of T1ρ and T2* relaxation values with dGEMRIC relaxation values. For the global ROI, there was a moderate correlation between dGEMRIC and T2* (moderate; rS = 0.63; p = 0.01). For the anterior ROI, a moderate or strong correlation was found between dGEMRIC and both T1ρ and T2*: dGEMRIC and T1ρ (strong; rS = -0.71; p = 0.003) and dGEMRIC and T2* (moderate; rS = 0.69; p = 0.004). There were no correlations for the posterior ROI. The mean dGEMRIC, T1ρ, and T2* relaxation values were not different between the anterior and posterior ROIs nor between the subdivided six ROIs.
CONCLUSION
Quantitative T1ρ and T2* cartilage mapping demonstrated a moderate correlation with dGEMRIC, anteriorly and globally, respectively. However, the clinical relevance of such a correlation remains unclear. Further research investigating the correlation of these two noncontrast techniques with clinical function and outcome scores is needed before broad implementation in the preoperative investigation of DDH.
LEVEL OF EVIDENCE
Level II, diagnostic study.
背景
延迟钆增强 MRI 软骨（dGEMRIC）是一种评估发育性髋关节发育不良（DDH）软骨健康的验证技术，它可以作为手术治疗反应的一种有帮助的预后指标。然而，dGEMRIC 需要静脉注射钆对比剂，这会增加成像过程的时间、费用和可能的不良反应。新型 MRI 软骨测绘技术，如 T1 rho (ρ) 和 T2*，可用于髋关节成像，无需任何对比剂，尽管尚不清楚它们是否与 dGEMRIC 等效。
问题/目的：本研究的目的是确定 DDH 患者三种软骨测绘技术（dGEMRIC、T1ρ 和 T2*）的弛豫值之间的相关性。
方法
15 例 DDH 患者（3 名男性，12 名女性；平均年龄 29 ± 9 岁）接受了术前髋关节周围截骨术，在 3T 下进行 dGEMRIC、T1ρ 和 T2MRI 定量软骨测绘。分析髋关节负重软骨的三个感兴趣区域（ROI）的 dGEMRIC、T1ρ 和 T2 测绘结果：整体 ROI、前侧和后侧 ROI，并进一步细分为内侧、中间和外侧，生成 6 个较小的 ROI。使用 Spearman 相关系数（rS）评估每个 ROI 的相应弛豫时间值之间的相关性，分为无、弱、中、强或极强。使用 Kruskal-Wallis 检验比较三种软骨测绘技术在每个细分 ROI 中的弛豫值。
结果
T1ρ 和 T2* 弛豫值与 dGEMRIC 弛豫值具有中度相关性。对于整体 ROI，dGEMRIC 与 T2* 之间存在中度相关性（中度；rS = 0.63；p = 0.01）。对于前侧 ROI，dGEMRIC 与 T1ρ 和 T2* 之间存在中度或强相关性：dGEMRIC 与 T1ρ（强；rS = -0.71；p = 0.003）和 dGEMRIC 与 T2*（中度；rS = 0.69；p = 0.004）。后侧 ROI 之间没有相关性。前侧和后侧 ROI 之间以及六个细分 ROI 之间的 dGEMRIC、T1ρ 和 T2* 弛豫值平均值无差异。
结论
定量 T1ρ 和 T2* 软骨测绘分别与 dGEMRIC 在前侧和整体上具有中度相关性。然而，这种相关性的临床意义尚不清楚。在将这些两种非对比技术广泛应用于 DDH 的术前研究之前，还需要进一步研究这些技术与临床功能和结果评分的相关性。
证据水平
二级，诊断研究。
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