Chérin E, Saïed A, Laugier P, Netter P, Berger G
Laboratoire d Imagerie Paramétrique URA CNRS 1458, Faculté de Médecine Broussais-Hôtel-Dieu, Paris, France.
Ultrasound Med Biol. 1998 Mar;24(3):341-54. doi: 10.1016/s0301-5629(97)00289-5.
The current study reports the sensitivity of acoustical parameters estimated at high frequency to the osteoarthritic morphological and structural changes in patellar cartilage in rat knees. Osteoarthritis (OA) was induced by a single intra-articular injection of mono-iodo-acetic acid in right knees. OA patellas and their contralateral controls were excised at regular intervals after injection and were examined in vitro with a scanning acoustical microscope operating with a poly(vinylidene di-fluoride) (PVDF) 80-MHz focused transducer. Cartilage thickness was estimated using B-scan images. The quantitative analysis of the radiofrequency signal backscattered by the cartilage was performed using integrated reflection coefficient (IRC) and apparent integrated backscatter (AIB), which were estimated in the 20-60-MHz frequency range. One week after injection, a cartilage thickness decrease was detected (-6%, on average) that preceded the significant hypertrophy (20.1%) that occurred 2 weeks after injection and could be due to tissue repair. From 1 week to 3 weeks after injection, the IRC of OA patellas was significantly lower than that of control patellas. The IRC difference increased with time from -3.3 +/- 2.4 dB at 1 week to -8.4 +/- 1.7 dB at 3 weeks. An AIB decrease was observed with time for both OA and control patellas (-2.9 to -4.2 dB per week). An AIB difference between OA and control patellas was detected from 1 week to 3 weeks after injection. This difference decreased with time. IRC variation reflects a change in acoustical impedance of the superficial layer of the cartilage and could be linked to a change in constituent content and/or to a disruption of fibers of the collagen network that led to the fibrillation of the cartilage surface. AIB variation reflects a change in shape, size and/or density of the scatterers and could be related to changes in the constituent content and in the organization of the matrix in the internal layer of the cartilage. IRC and AIB could provide information about the structural modifications of the cartilage due to osteoarthritis or to cartilage maturation.
本研究报告了高频估计的声学参数对大鼠膝关节髌软骨骨关节炎形态和结构变化的敏感性。通过在右膝单次关节内注射一碘乙酸诱导骨关节炎（OA）。注射后定期切除OA髌骨及其对侧对照，并使用配备聚偏二氟乙烯（PVDF）80MHz聚焦换能器的扫描声学显微镜进行体外检查。使用B扫描图像估计软骨厚度。在20-60MHz频率范围内，使用积分反射系数（IRC）和表观积分背向散射（AIB）对软骨背向散射的射频信号进行定量分析。注射后1周，检测到软骨厚度下降（平均-6%），这先于注射后2周出现的显著肥大（20.1%），可能是由于组织修复。注射后1周至3周，OA髌骨的IRC显著低于对照髌骨。IRC差异随时间增加，从1周时的-3.3±2.4dB增加到3周时的-8.4±1.7dB。OA和对照髌骨的AIB均随时间下降（每周-2.9至-4.2dB）。注射后1周至3周检测到OA和对照髌骨之间的AIB差异。这种差异随时间减小。IRC变化反映了软骨表层声阻抗的变化，可能与成分含量的变化和/或胶原网络纤维的破坏有关，导致软骨表面纤维化。AIB变化反映了散射体形状、大小和/或密度的变化，可能与软骨内层成分含量和基质组织的变化有关。IRC和AIB可以提供有关骨关节炎或软骨成熟导致的软骨结构改变的信息。
