MR超短回波PETRA-FS、T2*Mapping序列评估健康青年膝关节软骨的应用价值

The Application Value of PETRA-FS and T2*Mapping Sequences in Evaluating Knee Cartilage in Healthy Young Adults

摘要: 目的：运用MR超短回波时间成像径向采集逐点编码时间缩减联合脂肪抑制(pointwise encoding time reduction with radial acquisition combined fat suppression, PETRA-FS)序列及T2*mapping序列，探讨其在健康青年患者膝关节MR中的应用价值。方法：收集自2021年8月至2021年10月于青岛大学附属医院接受超短回波时间成像PETRA-FS序列、T2*mapping及FS FSE PDWI序列扫描的健康青年患者22名，将健康青年膝关节软骨划分为15个小亚区，共获取645个亚区，另将其分为承重区和非承重区，定量记录每个亚区软骨厚度和T2*值，按性别分组，应用独立样本t检验，比较各亚区合并后大部位的厚度及T2*值差异，总结膝关节整体软骨分布特点。结果：(1) 健康青年膝关节软骨厚度从高到低依次为髌软骨(3.74 mm)、股骨外侧髁(1.94 mm)、股骨外侧滑车(1.71 mm)、股骨内侧髁(1.46 mm)、胫骨内侧髁(1.21 mm)、胫骨外侧髁(1.11 mm)。(2) 健康青年男、女之间膝关节大部区域(除股骨内侧髁、胫骨内侧髁之外)的软骨厚度差异具有统计学意义(P < 0.05)；健康青年男、女之间膝关节大部区域(除股骨内侧髁、胫骨内侧髁之外)的T2*值差异无统计学意义(P > 0.05)；承重区和非承重区的T2*值差异具有统计学意义(P < 0.05)。结论：在健康青年中，性别可能是影响膝关节软骨厚度的重要因素，而软骨的T2*值可能受性别影响较小。本组的研究表明：T2*mapping和超短回波PETRA-FS序列能够较好的评价正常软骨并为其早期异常改变提供正常影像学参照。

Abstract: Objective: To explore the value of magnetic resonance (MR) ultrashort echo time imaging with pointwise encoding time reduction with radial acquisition combined fat suppression (PETRA-FS) sequence and the T2*mapping sequence in knee MR of healthy young adults. Methods: Totally 22 healthy young patients in The Affiliated Hospital of Qingdao University from August 2021 to Octo-ber 2021 were collected in this study: All subjects underwent FS FSE PDWI sequence scan, ultra-short echo time PETRA-FS sequence and T2*mapping sequence. Articular cartilage of knee was di-vided into 15 subregions, and a total of 645 subregions were obtained, in which the thickness and T2* values were semi-quantitative recorded in healthy young patients. And it was divided into load-bearing area and non-load-bearing area. All subjects were divided into two groups (13 men and 9 women) according to their gender. By using statistical analysis with t test, compared all sub-regions which were merged, the thickness distribution characteristics were summarized. Results: (1) The average cartilage thickness of knee in healthy young patients from thick to thin in turn was as followings: patellar cartilage (3.74 mm), lateral femoral condyle (1.94 mm), lateral femoral trochlea (1.71 mm), medial femoral condyle (1.46 mm), medial tibia condyle (1.21 mm), lateral tib-ia condyle (1.11 mm). (2) The thickness of the knee cartilage significantly differed between men and women (P < 0.05), besides the parts of medial femoral condyle and medial tibia condyle; The T2* values of the knee cartilage were only significantly differed between men and women in medial femoral condyle and medial tibia condyle (P < 0.05). In addition, the T2* values of load-bearing area and non-load-bearing area were with significantly difference (P < 0.05). Conclusion: In healthy young adults, gender may be an important factor affecting the thickness of knee cartilage, and the T2* value of cartilage may be less affected by gender. T2*mapping and PETRA-FS sequences can provide normal imaging reference.