Reproducibility of bone micro-architecture measurements in rodents by in vivo micro-computed tomography is maximized with three-dimensional image registration

Calcium magnesium phosphate cements (CMPCs) are promising bone substitutes and experience great interest in research. Therefore, in-vivo degradation behavior, osseointegration and biocompatibility of three-dimensional (3D) powder-printed CMPC scaffolds were investigated in the present study. The materials Mg225 (Ca0.75Mg2.25(PO4)2) and Mg225d (Mg225 treated with diammonium hydrogen phosphate (DAHP)) were implanted as cylindrical scaffolds (h = 5 mm, Ø = 3.8 mm) in both lateral femoral condyles in rabbits and compared with tricalcium phosphate (TCP). Treatment with DAHP results in the precipitation of struvite, thus reducing pore size and overall porosity and increasing pressure stability. Over 6 weeks, the scaffolds were evaluated clinically, radiologically, with Micro-Computed Tomography (µCT) and histological examinations. All scaffolds showed excellent biocompatibility. X-ray and in-vivo µCT examinations showed a volume decrease and increasing osseointegration over time. Structure loss and volume decrease were most evident in Mg225. Histologically, all scaffolds degraded centripetally and were completely traversed by new bone, in which the remaining scaffold material was embedded. While after 6 weeks, Mg225d and TCP were still visible as a network, only individual particles of Mg225 were present. Based on these results, Mg225 and Mg225d appear to be promising bone substitutes for various loading situations that should be investigated further.

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Heidelberg-mCT-Analyzer: a novel method for standardized microcomputed-tomography-guided evaluation of scaffold properties in bone and tissue research

Royal Society Open Science ◽

10.1098/rsos.150496 ◽

2015 ◽

Vol 2 (11) ◽

pp. 150496 ◽

Cited By ~ 10

Author(s):

Fabian Westhauser ◽

Christian Weis ◽

Melanie Hoellig ◽

Tyler Swing ◽

Gerhard Schmidmaier ◽

...

Keyword(s):

Tissue Engineering ◽

Bone Tissue Engineering ◽

Bone Tissue ◽

Three Dimensional ◽

Characteristic Parameter ◽

Micro Computed Tomography ◽

Mineral Density ◽

Independent Analysis ◽

Scaffold Properties

Bone tissue engineering and bone scaffold development represent two challenging fields in orthopaedic research. Micro-computed tomography (mCT) allows non-invasive measurement of these scaffolds’ properties in vivo . However, the lack of standardized mCT analysis protocols and, therefore, the protocols’ user-dependency make interpretation of the reported results difficult. To overcome these issues in scaffold research, we introduce the Heidelberg-mCT-Analyzer. For evaluation of our technique, we built 10 bone-inducing scaffolds, which underwent mCT acquisition before ectopic implantation (T0) in mice, and at explantation eight weeks thereafter (T1). The scaffolds’ three-dimensional reconstructions were automatically segmented using fuzzy clustering with fully automatic level-setting. The scaffold itself and its pores were then evaluated for T0 and T1. Analysing the scaffolds’ characteristic parameter set with our quantification method showed bone formation over time. We were able to demonstrate that our algorithm obtained the same results for basic scaffold parameters (e.g. scaffold volume, pore number and pore volume) as other established analysis methods. Furthermore, our algorithm was able to analyse more complex parameters, such as pore size range, tissue mineral density and scaffold surface. Our imaging and post-processing strategy enables standardized and user-independent analysis of scaffold properties, and therefore is able to improve the quantitative evaluations of scaffold-associated bone tissue-engineering projects.

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Micro-Computed Tomography-Based Three-Dimensional Anatomical Structure of the Region Around the Pterygoid Hamulus

The Cleft Palate-Craniofacial Journal ◽

10.1177/10556656211036302 ◽

2021 ◽

pp. 105566562110363

Author(s):

Jiuli Zhao ◽

Hengyuan Ma ◽

Yongqian Wang ◽

Tao Song ◽

Chanyuan Jiang ◽

...

Keyword(s):

Computed Tomography ◽

Treatment Options ◽

Muscle Fibers ◽

Three Dimensional ◽

Anatomical Structure ◽

Micro Computed Tomography ◽

3 Dimensional ◽

Middle Ear Ventilation ◽

Optimal Approach ◽

Velopharyngeal Function

Objective Palatoplasty would involve the structures around the pterygoid hamulus. However, clinicians hold different opinions on the optimal approach for the muscles and palatine aponeurosis around the pterygoid hamulus. The absence of a consensus regarding this point can be attributed to the lack of investigations on the exact anatomy of this region. Therefore, we used micro-computed tomography to examine the anatomical structure of the region surrounding the pterygoid hamulus. Design Cadaveric specimens were stained with iodine–potassium iodide and scanned by micro-computed tomography to study the structures of the tissues, particularly the muscle fibers. We imported Digital Imaging and Communications in Medicine images to Mimics to reconstruct a 3-dimensional model and simplified the model. Results Three muscles were present around the pterygoid hamulus, namely the palatopharyngeus (PP), superior constrictor (SC), and tensor veli palatini (TVP). The hamulus connects these muscles as a key pivot. The TVP extended to the palatine aponeurosis, which bypassed the pterygoid hamulus, and linked the PP and SC. Some muscle fibers of the SC originated from the hamulus, the aponeurosis of which was wrapped around the hamulus. There was a distinct gap between the pterygoid hamulus and the palatine aponeurosis. This formed a pulley-like structure around the pterygoid hamulus. Conclusions Transection or fracture of the palatine aponeurosis or pterygoid hamulus, respectively, may have detrimental effects on the muscles around the pterygoid hamulus, which play essential roles in the velopharyngeal function and middle ear ventilation. Currently, cleft palate repair has limited treatment options with proven successful outcomes.

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Extraction of Cervical Lymph Nodes Based on Three-Dimensional Image Registration

10.23919/iccas52745.2021.9649797 ◽

2021 ◽

Author(s):

Nozomi Shime ◽

Tohru Kamiya ◽

Takayuki Ishida

Keyword(s):

Image Registration ◽

Lymph Nodes ◽

Three Dimensional ◽

Cervical Lymph Nodes ◽

Dimensional Image

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Microstructural Observation with MicroCT and Histological Analysis of Human Alveolar Bone Biopsy from a Planned Implant Site: A Case Report

The Open Dentistry Journal ◽

10.2174/1874210601307010047 ◽

2013 ◽

Vol 7 (1) ◽

pp. 47-54 ◽

Cited By ~ 2

Author(s):

Emi Yamashita-Mikami ◽

Mikako Tanaka ◽

Naoki Sakurai ◽

Kazuho Yamada ◽

Hayato Ohshima ◽

...

Keyword(s):

Computed Tomography ◽

Bone Tissue ◽

Alveolar Bone ◽

Bone Biopsy ◽

Three Dimensional ◽

Bone Sample ◽

Biopsy Sample ◽

Micro Computed Tomography ◽

Metabolic Markers ◽

Normal Ranges

The subject was a 53-year-old male. An alveolar bone sample was obtained from the site of the lower left first molar, before dental implant placement. Although the details of the trabecular structure were not visible with conventional computed tomography, micro-computed tomography (microCT) three-dimensional images of the alveolar bone biopsy sample showed several plate-like trabeculae extending from the lingual cortical bone. Histological observations of the bone sample revealed trabeculae, cuboidal osteoblasts, osteoclasts and hematopoietic cells existing in the bone tissue at the implantation site. Bone metabolic markers and calcaneal bone density were all within normal ranges, indicating no acceleration of the patient’s bone metabolism.Using microCT, and histological and histomorphometrical techniques, a great deal of valuable information about the bone tissue was obtained from a biopsy sample extracted from the patient’s planned implant site.

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