scholarly journals Peer Review #3 of "Three-dimensional visualisation of the internal anatomy of the sparrowhawk (Accipiter nisus) forelimb using contrast-enhanced micro-computed tomography (v0.1)"

Author(s):  
B Metscher
Zoosymposia ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 172-191 ◽  
Author(s):  
ALEXANDER ZIEGLER

Recent studies have shown that micro-computed tomography (µCT) must be considered one of the most suitable techniques for the non-invasive, three-dimensional (3D) visualization of metazoan hard parts. In addition, µCT can also be used to visualize soft part anatomy non-destructively and in 3D. In order to achieve soft tissue contrast using µCT based on X-ray attenuation, fixed specimens must be immersed in staining solutions that include heavy metals such as silver (Ag), molybdenum (Mo), osmium (Os), lead (Pb), or tungsten (W). However, while contrast-enhancement has been successfully applied to specimens pertaining to various higher metazoan taxa, echinoderms have thus far not been analyzed using this approach. In order to demonstrate that this group of marine invertebrates is suitable for contrast-enhanced µCT as well, the present study provides results from an application of this technique to representative species from all five extant higher echinoderm taxa. To achieve soft part contrast, freshly fixed and museum specimens were immersed in an ethanol solution containing phosphotungstic acid and then scanned using a high-resolution desktop µCT system. The acquired datasets show that the combined visualization of echinoderm soft and hard parts can be readily accomplished using contrast-enhanced µCT in all extant echinoderm taxa. The results are compared with µCT data obtained using unstained specimens, with conventional histological sections, and with data previously acquired using magnetic resonance imaging, a technique known to provide excellent soft tissue contrast despite certain limitations. The suitability for 3D visualization and modeling of datasets gathered using contrast-enhanced µCT is illustrated and applications of this novel approach in echinoderm research are discussed.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3039 ◽  
Author(s):  
Fernanda Bribiesca-Contreras ◽  
William I. Sellers

BackgroundGross dissection is a widespread method for studying animal anatomy, despite being highly destructive and time-consuming. X-ray computed tomography (CT) has been shown to be a non-destructive alternative for studying anatomical structures. However, in the past it has been limited to only being able to visualise mineralised tissues. In recent years, morphologists have started to use traditional X-ray contrast agents to allow the visualisation of soft tissue elements in the CT context. The aim of this project is to assess the ability of contrast-enhanced micro-CT (μCT) to construct a three-dimensional (3D) model of the musculoskeletal system of the bird wing and to quantify muscle geometry and any systematic changes due to shrinkage. We expect that this reconstruction can be used as an anatomical guide to the sparrowhawk wing musculature and form the basis of further biomechanical analysis of flight.MethodsA 3% iodine-buffered formalin solution with a 25-day staining period was used to visualise the wing myology of the sparrowhawk (Accipiter nisus). μCT scans of the wing were taken over the staining period until full penetration of the forelimb musculature by iodine was reached. A 3D model was reconstructed by manually segmenting out the individual elements of the avian wing using 3D visualisation software.ResultsDifferent patterns of contrast were observed over the duration of the staining treatment with the best results occurring after 25 days of staining. Staining made it possible to visualise and identify different elements of the soft tissue of the wing. Finally, a 3D reconstruction of the musculoskeletal system of the sparrowhawk wing is presented and numerical data of muscle geometry is compared to values obtained by dissection.DiscussionContrast-enhanced μCT allows the visualisation and identification of the wing myology of birds, including the smaller muscles in the hand, and provides a non-destructive way for quantifying muscle volume with an accuracy of 96.2%. By combining contrast-enhanced μCT with 3D visualisation techniques, it is possible to study the individual muscles of the forelimb in their original position and 3D design, which can be the basis of further biomechanical analysis. Because the stain can be washed out post analysis, this technique provides a means of obtaining quantitative muscle data from museum specimens non-destructively.


2019 ◽  
Author(s):  
S.J.O. Rytky ◽  
A. Tiulpin ◽  
T. Frondelius ◽  
M.A.J. Finnilä ◽  
S.S. Karhula ◽  
...  

AbstractObjectiveTo develop and validate a machine learning (ML) approach for automatic three-dimensional (3D) histopathological grading of osteochondral samples imaged with contrast-enhanced micro-computed tomography (CEμCT).DesignOsteochondral cores from 24 total knee arthroplasty patients and 2 asymptomatic cadavers (n = 34, Ø = 2 mm; n = 45, Ø = 4 mm) were imaged using CEμCT with phosphotungstic acid-staining. Volumes-of-interest (VOI) in surface (SZ), deep (DZ) and calcified (CZ) zones were extracted depthwise and subjected to dimensionally reduced Local Binary Pattern-textural feature analysis. Regularized Ridge and Logistic regression (LR) models were trained zone-wise against the manually assessed semi-quantitative histopathological CEμCT grades (Ø = 2 mm samples). Models were validated using nested leave-one-out cross-validation and an independent test set (Ø = 4 mm samples). The performance was assessed using Spearman’s correlation, Average Precision (AP) and Area under the Receiver Operating Characteristic Curve (AUC).ResultsHighest performance on cross-validation was observed for SZ, both on Ridge regression (ρ = 0.68, p < 0.0001) and LR (AP = 0.89, AUC = 0.92). The test set evaluations yielded decreased Spearman’s correlations on all zones. For LR, performance was almost similar in SZ (AP = 0.89, AUC = 0.86), decreased in CZ (AP = 0.71→0.62, AUC = 0.77→0.63) and increased in DZ (AP = 0.50→0.83, AUC = 0.72→0.72).ConclusionWe showed that the ML-based automatic 3D histopathological grading of osteochondral samples is feasible from CEμCT. The developed method can be directly applied by OA researchers since the grading software and all source codes are publicly available.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Javier Alba-Tercedor ◽  
Wayne B. Hunter ◽  
Ignacio Alba-Alejandre

AbstractThe Asian citrus psyllid (ACP), Diaphorina citri, is a harmful pest of citrus trees that transmits Candidatus Liberibacter spp. which causes Huanglongbing (HLB) (citrus greening disease); this is considered to be the most serious bacterial disease of citrus plants. Here we detail an anatomical study of the external and internal anatomy (excluding the reproductive system) using micro-computed tomography (micro-CT). This is the first complete 3D micro-CT reconstruction of the anatomy of a psylloid insect and includes a 3D reconstruction of an adult feeding on a citrus leaf that can be used on mobile devices. Detailed rendered images and videos support first descriptions of coxal and scapus antennal glands and sexual differences in the internal anatomy (hindgut rectum, mesothoracic ganglion and brain). This represents a significant advance in our knowledge of ACP anatomy, and of psyllids in general. Together the images, videos and 3D model constitute a unique anatomical atlas and are useful tools for future research and as teaching aids.


2021 ◽  
pp. 105566562110363
Author(s):  
Jiuli Zhao ◽  
Hengyuan Ma ◽  
Yongqian Wang ◽  
Tao Song ◽  
Chanyuan Jiang ◽  
...  

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.


2013 ◽  
Vol 7 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Emi Yamashita-Mikami ◽  
Mikako Tanaka ◽  
Naoki Sakurai ◽  
Kazuho Yamada ◽  
Hayato Ohshima ◽  
...  

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.


Sign in / Sign up

Export Citation Format

Share Document