Department of Radiology, Peking University People's Hospital, Beijing 100044, China.
Chin Med J (Engl). 2012 Mar;125(5):843-50.
Quantitative T2 mapping has been a widely used method for the evaluation of pathological cartilage properties, and the histological assessment system of osteoarthritis in the rabbit has been published recently. The aim of the study was to investigate the effectiveness of quantitative T2 mapping evaluation for articular cartilage lesions of a rabbit model of anterior cruciate ligament transection (ACLT) osteoarthritis.
Twenty New Zealand White (NZW) rabbits were divided into ACLT surgical group and sham operated group equally. The anterior cruciate ligaments of the rabbits in ACLT group were transected, while the joints were closed intactly in sham operated group. Magnetic resonance (MR) examinations were performed on 3.0T MR unit at week 0, week 6, and week 12. T2 values were computed on GE ADW4.3 workstation. All rabbits were killed at week 13, and left knees were stained with Haematoxylin and Eosin. Semiquantitative histological grading was obtained according to the osteoarthritis cartilage histopathology assessment system. Computerized image analysis was performed to quantitate the immunostained collagen type II.
The average MR T2 value of whole left knee cartilage in ACLT surgical group ((29.05±12.01) ms) was significantly higher than that in sham operated group ((24.52±7.97) ms) (P=0.024) at week 6. The average T2 value increased to (32.18±12.79) ms in ACLT group at week 12, but remained near the baseline level ((27.66±8.08) ms) in the sham operated group (P=0.03). The cartilage lesion level of left knee in ACLT group was significantly increased at week 6 (P=0.005) and week 12 (P<0.001). T2 values had positive correlation with histological grading scores, but inverse correlation with optical densities (OD) of type II collagen.
This study demonstrated the reliability and practicability of quantitative T2 mapping for the cartilage injury of rabbit ACLT osteoarthritis model.
定量 T2 映射已被广泛用于评估病理性软骨特性，最近已发布了兔骨关节炎的组织学评估系统。本研究旨在探讨定量 T2 映射评估对前交叉韧带切断（ACLT）兔骨关节炎模型关节软骨病变的有效性。
将 20 只新西兰白兔（NZW）等分为 ACLT 手术组和假手术组。ACLT 组的前交叉韧带被切断，而假手术组的关节则完整闭合。在 3.0T MR 单元上在第 0、6 和 12 周进行磁共振（MR）检查。在 GE ADW4.3 工作站上计算 T2 值。所有兔子在第 13 周被处死，左膝用苏木精和伊红染色。根据骨关节炎软骨组织病理学评估系统获得半定量组织学分级。通过计算机图像分析对免疫染色的 II 型胶原进行定量。
ACLT 手术组左膝软骨的平均 MR T2 值（（29.05±12.01）ms）在第 6 周时明显高于假手术组（（24.52±7.97）ms）（P=0.024）。在 ACLT 组中，T2 值在第 12 周增加到（32.18±12.79）ms，但在假手术组中仍接近基线水平（（27.66±8.08）ms）（P=0.03）。第 6 周（P=0.005）和第 12 周（P<0.001），ACLT 组左膝软骨病变程度明显增加。T2 值与组织学分级评分呈正相关，与 II 型胶原的光密度（OD）呈负相关。
本研究证明了定量 T2 映射对兔 ACLT 骨关节炎模型软骨损伤的可靠性和实用性。
