Radiology Institute, University Medical Centre Ljubljana, Ljubljana, Slovenia.
Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
J Neuroimaging. 2022 May;32(3):420-429. doi: 10.1111/jon.12982. Epub 2022 Feb 28.
Understanding nerve microanatomy is important as different neuropathies and some nerve neoplasms present with fascicle enlargement. The aim of our study was to gain clinically oriented knowledge on nerve fascicular anatomy using imaging modalities.
On a cadaveric upper extremity, high-resolution ultrasound (HRUS) scan with 22 MHz probe was performed. Sections of the median and ulnar nerves were excised at the level of the distal arm and after magnetic resonance microscopy (MRM), histological cross-sections (HCS) were prepared. Cross-referencing of the MRM and HRUS images with HCS was performed. Fascicle and nerve contouring was performed with morphometric software in order to assess nerve and fascicular cross-sectional area (CSA), fascicle count, and interfascicular distances. Based on fascicle differentiation, factual fascicle (FF) group and fascicular cluster (FC) group were defined.
On the cross-referenced imaging material, fascicles were differentiated in 92.7% on MRM and in 57.3% on HRUS. High to very high positive correlation among imaging material was observed for the fascicle CSA. FF depiction was 30.1% on HRUS. In comparison to the FF group, the FC group had significantly larger fascicle CSA and shorter interfascicular distances.
The findings of our study contribute to understanding of fascicle depiction on imaging modalities. HRUS offers good visualization of fascicles. The capability of differentiating fascicles is modality specific and depends on the fascicle CSA and the amount of interfascicular epineurium.
了解神经微观解剖结构非常重要，因为不同的神经病变和一些神经肿瘤会表现出束状增粗。我们研究的目的是利用成像方式获得具有临床导向性的神经束解剖知识。
在上肢尸体标本上，使用 22MHz 探头进行高分辨率超声（HRUS）扫描。在臂远端水平切取正中神经和尺神经的节段，进行磁共振显微镜（MRM）检查后，制备组织学横切面（HCS）。对 MRM 和 HRUS 图像与 HCS 进行交叉参考。使用形态计量软件对神经和束状横截面面积（CSA）、束计数和束间距离进行神经和束轮廓描绘。基于束的分化，将事实束（FF）组和束簇（FC）组进行定义。
在交叉参考的成像材料中，MRM 可将束状结构区分开来，其准确率为 92.7%，HRUS 为 57.3%。在成像材料中，束 CSA 之间存在高度到非常高度的正相关。HRUS 上 FF 的显示率为 30.1%。与 FF 组相比，FC 组的束 CSA 更大，束间距离更短。
本研究的发现有助于理解成像方式上的束状描绘。HRUS 可很好地显示束状结构。区分束的能力具有特定的模态依赖性，取决于束 CSA 和束间神经外膜的数量。
