【 文献重点摘要 】
 

Background/purpose: In recent years, increasing use of injectable resorbable fillings has been reported for facial wrinkle treatment. However, the physiological processes involved such as the localization and subsequent diffusion of the injected product in skin tissues are poorly documented. This may be noninvasively achieved using quantitative magnetic resonance imaging (MRI), which is duly presented in this pilot study.

Methods: Hyaluronic acid (HA) was injected intradermally in the forearm of a young male volunteer. High-resolution MRI scans using a surface antenna were performed just after injection, and after 2, 4 and 9 months. Morphological images were compared with transverse relaxation time (T2) images computed from a pixel-by-pixel analysis.

Results: On high-resolution morphological MR images the HA injection is barely visible, but with quantitative MRI the zone of injection is clearly seen. This is due to HA having a distinctly different transverse relaxation time, T2 ~ 600 ms, compared with dermal and hypodermal tissues, 35 and 80 ms, respectively.

Conclusion: These preliminary results demonstrate the ability of the T2 images for in vivo visualization of the filler agent and also for characterization of tissue modifications. In addition, the diffusion and progressive degradation of the filler agent can be monitored by T2 measurements over time.

Keywords: filler agent, hyaluronic acid, quantitative MR images

背景/目的：近年来，越来越多的报道使用可注射可吸收填充物治疗面部皱纹。然而，所涉及的生理过程，如注射产物在皮肤组织中的定位和随后的扩散，却鲜有文献记载。这可能是使用定量磁共振成像(MRI)非侵入性地实现的，这是在这项初步研究中适时提出的。

方法：对一名年轻男性志愿者前臂皮内注射透明质酸(HA)。注射后即刻、2、4和9个月后，使用表面天线进行高分辨率MRI扫描。形态学图像与从逐个像素分析计算的横向弛豫时间(T2)图像进行比较。

结果：在高分辨率形态学MR图像上，HA注射几乎看不见，而在定量MRI上，注射区域清晰可见。这是由于HA与真皮和皮下组织相比具有明显不同的横向弛豫时间，T2~600ms，分别为35ms和80ms。

结论：这些初步结果表明T2图像能够在活体内显示填充剂，也可以用于组织修饰的表征。此外，可以通过T2测量来监测填充剂随时间的扩散和逐步降解。

关键词：填充剂、透明质酸、定量磁共振成像