3.0T MRI T2-mapping对膝关节软骨退变的评估价值

3.0 T MRI T2-mapping evaluates knee cartilage degeneration

目的将MRI表现与病理学对照,研究膝关节胫骨平台软骨退变的MRT2值、T2-mapping表现及其评估关节软骨退变的价值。材料与方法选取全膝关节置换术患者的31个膝关节中符合纳入标准的18个膝关节胫骨平台进行T2-mapping(T2弛豫时间)成像,共获取98个软骨亚区(标本),以病理学Mankin分级为标准,评估T2值、T2-mapping伪彩图发现软骨退变的能力。根据组织学Mankin分级标准把不同退变程度的软骨T2值分5组输入数据库,应用单因素方差分析,组间比较采用LSD检验进行统计学处理。结果 0级(正常)软骨的T2值[(32.28+4.15)ms]与Ⅱ级软骨[(34.42+5.76)ms]、Ⅰ级软骨的T2值[(37.72+4.83)ms]与Ⅱ级软骨、Ⅲ级软骨的T2值[(41.63+6.10)ms]与Ⅳ级软骨[(45.98+7.32)ms]两两比较,差异均无统计学意义(P值均>0.05);Ⅰ级软骨的T2值与Ⅲ级及Ⅳ级、Ⅱ级软骨的T2值与Ⅲ级和Ⅳ级分别两两比较,差异均有统计学意义(P值均<0.05)。总体上,T2值伴随软骨退变程度的增加而明显升高,其中软骨退变Ⅱ级较Ⅰ级的T2值轻度降低,但Ⅱ级与Ⅰ级及正常软骨T2值之间差异无统计学意义(P值均>0.05)。T2-mapping伪彩图信号改变可以敏感的发现软骨退变,但无法区分软骨的退变程度。结论关节软骨的T2值与软骨退变程度有着明显的相关性,随着软骨退变程度的加重T2值明显升高,是发现早期软骨退变的敏感方法。

Objective： To explore the MRI value in diagnosing articular cartilage degeneration of knee joint by comparing MRI T2 value, T2-mapping appearances of tibial plateau cartilage degeneration with the corresponding pathological results. Materials and Methods： Eighteen of thirty-one knee joints undergone whole knee arthroplasty were chosen for MRI T2-mapping （T2 relaxation time） imaging. Ninety- eight cartilage subregions （specimens） were confirmed pathologically by a standard of Mankin＇s pathological grade, The different degrees of histological degenerated cartilage were divided into five groups basing on Mankin＇s grading standard. All the T2 values were inputted the database and variance comparisons between groups were tested by One-Way ANOVA and LSD test to evaluate the ability of T2 value and T2-mapping artificial color image on displaying cartilage degeneration. Results： No statistical difference of T2 value was found between normal group [（32.28± 4.15） ms] and grade II [（34.42±5.76） ms] group, grade I [（37.72±4.83） ms] and grade 1I, grade Ili [（41.63±6.10） ms] and grade IV [（45.98±7.32） ms] （P〉0.05） . Significant difference of T2 value was found between grade I and grade II1 or grade IV, grade II and grade III or grade IV（P〈0.05）. Overall, T2 value could get increased significantly resulted from the severity of cartilage degeneration and the T2 value of grade I[ group was slightly lower than that of grade I, but there was no statistical difference between grade II group and normal group or grade I （P〉0.05）. The signal change on T2 -mapping artificial color image could sensitively display cartilage degeneration but hardly describe the degree of degeneration of cartilage. Conclusions： The T2 value of the articular cartilage could increase significantly with cartilage deterioration, which was highly related to the degree of cartilage degeneration and could be considered as a sensitive method to detect early cartilage degeneration.