Iodine and freeze-drying enhanced high-resolution MicroCT imaging for reconstructing 3D intraneural topography of human peripheral nerve fascicles

Yan, Liwei; Guo, Yongze; Qi, Jian; Zhu, Qian; Gu, Liqiang; Zheng, Canbin; Lin, Tao; Lu, Yutong; Zeng, Zitao; Yu, Sha; Zhu, Shuang; Zhou, Xiang; Zhang, Xi; Du, Yunfei; Yao, Zhaolin; Lu, Yao; Liu, Xiaolin

doi:10.1016/j.jneumeth.2017.06.009

Cited by 23 publications

(24 citation statements)

References 40 publications

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“…Currently, CT and microCT are standard tools for the visualisation of bone structure. However, the imaging of biological soft tissue, limited by the low intrinsic X-ray contrast of non-mineralised tissues, has increased in the recent years with methods incorporating the use of contrast enhancement agents such as osmium , reduced silver (Mizutani et al, 2007), resin perfusion (Wirkner and Prendini, 2007;Wirkner and Richter, 2004), and iodine (de Crespigny et al, 2008;Degenhardt et al, 2010;Gignac and Kley, 2014;Heimel et al, 2019;Jeffery et al, 2011;Metscher, 2009;Yan et al, 2017). It has been successfully applied to tendons (Kalson et al, 2012), ligaments (Shearer et al, 2014) and nerves (Yan et al, 2017;Zhu et al, 2016).…”

Section: Microctmentioning

confidence: 99%

“…Currently, they require phase contrast scanners which may be inaccessible and time-limited and are expensive. The imaging data obtained requires considerable CPU and GPU memory in addition to the use of supercomputers (Gong et al, 2016;Yan et al, 2017). Long pre-processing procedures are needed that may allow movement of the specimen during the scan or cause destruction of the sample, so that subsequent validation with histology or other techniques, such as neural tracers, is not possible.…”

Section: Microctmentioning

confidence: 99%

“…There are two main methods for sample preparation previously used in similar studies; including freeze-drying (Yan et al, 2017) and paraffin embedding (Scott et al, 2015). These were both tried and discarded.…”

Section: Experimental Designmentioning

confidence: 99%

“…The rat sciatic nerves were scanned with the parameters in the following table (Table 1). The initial parameters used were roughly based on previous studies for soft tissues (du Plessis et al, 2017;Metscher, 2009;Senter-Zapata et al, 2016;Yan et al, 2017). The same parameters were used for all scans of the rat sciatic nerves stained for different lengths of time as to allow the differentiation in the contrast in the scans to be attributed only to the staining time.…”

Section: Microct Scanningmentioning

confidence: 99%

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MicroCT optimisation for imaging fascicular anatomy in peripheral nerves

Thompson

Ravagli

Mastitskaya

et al. 2019

Preprint

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Vagus nerve stimulation (VNS) is a promising therapy for treatment of various conditions resistant to standard therapeutics. However, due to the lack of understanding of the fascicular organisation of the vagus nerve, VNS leads to unwanted off-target effects. Micro-computed tomography (microCT) can be used to trace fascicles from periphery and image fascicular anatomy. In this work we optimised the microCT protocol of the rat sciatic and subsequent pig vagus nerves. After differential staining, the optimal staining time was selected and scanning parameters were altered in subsequent scans. Scans were reconstructed, visualised in ImageJ and fascicles segmented with a custom algorithm in Matlab to determine ultimate parameters for tracking of the nerve. Successful segmentation for tracking of individual fascicles was achieved after 24 hours and 120 hours of staining with Lugol's solution (1% total iodine) for rat sciatic and pig vagus nerves, respectively, and the following scanning parameters: 4 µm voxel size, 35 kVp energy, 114 µA current, 4 W power, 0.25 fps in 4 s exposure time, 3176 projections and a molybdenum target. The optimised microCT protocol allows for segmentation and tracking of the fascicles within the nerve. This will be used to scan the full length of the pig, and possibly, the human vagus nerves. The resulting segmentation map of the functional anatomical organisation of the vagus nerve will enable selective VNS ultimately allowing for the avoidance of the off-target effects and improving its therapeutic efficacy.

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Section: Microctmentioning

confidence: 99%

Section: Microctmentioning

confidence: 99%

Section: Experimental Designmentioning

confidence: 99%

Section: Microct Scanningmentioning

confidence: 99%

See 2 more Smart Citations

MicroCT optimisation for imaging fascicular anatomy in peripheral nerves

Thompson

Ravagli

Mastitskaya

et al. 2019

Preprint

View full text Add to dashboard Cite

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“…An anatomically accurate model of a peripheral nerve can be constructed using data acquired from a variety of imaging modalities, including histological cross-sections, Micro-Computed Tomography (MicroCT), Optical Projection Tomography (OPT), or Magnetic Resonance Imaging (MRI) (14,16,17). To date, either fully manual or semi-automatic procedures have been used to reconstruct peripheral nerve models from image data (17–19).…”

Section: Introductionmentioning

confidence: 99%

Automatic Three-Dimensional Reconstruction of Fascicles in Peripheral Nerves from Histological Images

Tovbis

Zariffa

Agur

et al. 2020

Preprint

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AbstractComputational studies can be used to support the development of peripheral nerve interfaces, but currently use simplified models of nerve anatomy, which may impact the applicability of simulation results. To better quantify and model neural anatomy across the population, we have developed an algorithm to automatically reconstruct accurate peripheral nerve models from histological cross-sections. We acquired serial median nerve cross-sections from human cadaveric samples, staining one set with hematoxylin and eosin (H&E) and the other using immunohistochemistry (IHC) with anti-neurofilament antibody. We developed a four-step processing pipeline involving registration, fascicle detection, segmentation, and reconstruction. We compared the output of each step to manual ground truths, and additionally compared the final models to commonly used extrusions, via intersection-over-union (IOU). Fascicle detection and segmentation required the use of a neural network and active contours in H&E-stained images, but only simple image processing methods for IHC-stained images. Reconstruction achieved an IOU of 0.42±0.07 for H&E and 0.37±0.16 for IHC images, with errors partially attributable to global misalignment at the registration step, rather than poor reconstruction. This work provides a quantitative baseline for fully automatic construction of peripheral nerve models. Our models provided fascicular shape and branching information that would be lost via extrusion.

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Three‐dimensional reconstruction of internal fascicles and microvascular structures of human peripheral nerves

Yan

Liu

et al. 2019

Numer Methods Biomed Eng

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Biofabricated nanostructured and microstructured scaffolds have exhibited great potential for nerve tissue regeneration and functional restoration, and prevascularization and biotransportation within 3D fascicle structures are critical. Unfortunately, an ideal internal fascicle and microvascular model of human peripheral nerves is lacking. In this study, we used microcomputed tomography (microCT) to acquire high‐resolution images of the human sciatic nerve. We propose a novel deep‐learning network technique, called ResNetH3D‐Unet, to segment fascicles and microvascular structures. We reconstructed 3D intraneural fascicles and microvascular topography to quantify the fascicle volume ratio (FVR), microvascular volume ratio (MVR), microvascular to fascicle volume ratio (MFVR), fascicle surface area to volume ratio (FSAVR), and microvascular surface area to volume ratio (MSAVR) of human samples. The frequency distributions of the fascicle diameter, microvascular diameter, and fascicle‐to‐microvasculature distance were analyzed. The obtained microCT analysis and reconstruction provided high‐resolution microstructures of human peripheral nerves. Our proposed ResNetH3D‐Unet method for fascicle and microvasculature segmentation yielded a mean intersection over union (IOU) of 92.1% (approximately 5% higher than the U‐net IOU). The 3D reconstructed model showed that the internal microvasculature runs longitudinally within the internal epineurium and connects to the external vasculature at some points. Analysis of the 3D data indicated a 48.2 ± 3% FVR, 23.7 ± 1.8% MVR, 4.9 ± 0.5% MFVR, 7.26 ± 2.58 mm‐1 FSAVR, and 1.52 ± 0.52 mm‐1 MSAVR. A fascicle diameter of 0.98 mm, microvascular diameter of 0.125 mm, and microvasculature‐to‐fascicle distance of 0.196 mm were most frequent. This study provides fundamental data and structural references for designing bionic scaffolding constructs with 3D microvascular and fascicle distributions.

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Iodine and freeze-drying enhanced high-resolution MicroCT imaging for reconstructing 3D intraneural topography of human peripheral nerve fascicles

Cited by 23 publications

References 40 publications

MicroCT optimisation for imaging fascicular anatomy in peripheral nerves

MicroCT optimisation for imaging fascicular anatomy in peripheral nerves

Automatic Three-Dimensional Reconstruction of Fascicles in Peripheral Nerves from Histological Images

Three‐dimensional reconstruction of internal fascicles and microvascular structures of human peripheral nerves

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