The development and structure of the mesentery.

The position of abdominal organs, and mechanisms by which these are centrally connected, are currently described in peritoneal terms. As part of the peritoneal model of abdominal anatomy, there are multiple mesenteries. Recent findings point to an alternative model in which digestive organs are connected to a single mesentery. Given that direct evidence of this is currently lacking, we investigated the development and shape of the entire mesentery. Here we confirm that, within the abdomen, there is one mesentery in which all abdominal digestive organs develop and remain connected to. We show that all abdominopelvic organs are organised into two, discrete anatomical domains, the mesenteric and non-mesenteric domain. A similar organisation occurs across a range of animal species. The findings clarify the anatomical foundation of the abdomen; at the foundation level, the abdomen comprises a visceral (i.e. mesenteric) and somatic (i.e. musculoskeletal) frame. The organisation at that level is a fundamental order that explains the positional anatomy of all abdominopelvic organs, vasculature and peritoneum. Collectively, the findings provide a novel start point from which to systemically characterise the abdomen and its contents.

Corrigendum to "Neuroprotective effect of Sanqi Tongshuan Tablets on sequelae post-stroke in rats" [Chinese Herbal Medicines 11 (2019) 45-51].

[This corrects the article DOI: 10.1016/j.chmed.2018.12.002.].

Interactive three-dimensional teaching models of the female and male pelvic floor.

Controversies regarding structure and function of the pelvic floor persist because of its poor accessibility and complex anatomical architecture. Most data are based on dissection. This "surgical" approach requires profound prior knowledge, because applying the scalpel precludes a "second look." The "sectional" approach does not entail these limitations, but requires segmentation of structures and three-dimensional reconstruction. This approach has produced several "Visible Human Projects." We dealt with limited spatial resolution and difficult-to-segment structures by proceeding from clear-cut to more fuzzy boundaries and comparing segmentation between investigators. We observed that the bicipital levator ani muscle consisted of pubovisceral and puborectal portions; that the pubovisceral muscle formed, together with rectococcygeal and rectoperineal muscles, a rectal diaphragm; that the external anal sphincter consisted of its subcutaneous portion and the puborectal muscle only; that the striated urethral sphincter had three parts, of which the middle (urethral compressor) was best developed in females and the circular lower ("membranous") best in males; that the rectourethral muscle, an anterior extension of the rectal longitudinal smooth muscle, developed a fibrous node in its center (perineal body); that the perineal body was much better developed in females than males, so that the rectourethral subdivision into posterior rectoperineal and anterior deep perineal muscles was more obvious in females; that the superficial transverse perineal muscle attached to the fibrous septa of the ischioanal fat; and that the uterosacral ligaments and mesorectal fascia colocalized. To facilitate comprehension of the modified topography we provide interactive 3D-PDFs that are freely available for teaching purposes. Clin. Anat. 33:275-285, 2020. © 2019 Wiley Periodicals, Inc.

Architecture of structures in the urogenital triangle of young adult males; comparison with females.

The fibro-muscular architecture of the urogenital triangle remains contentious. Reasons are small size of the constituting structures and poor visibility with most imaging methods. We reinvestigated the area in serial sections of three males (21-38 years old) of the American and Chinese Visible Human Projects and two 26-week-old male fetuses, and compared the findings with earlier observations in females. The mass of the levator ani muscle was approximately twofold smaller and its funnel shape steeper in males than females. In the levator hiatus, a strand of the smooth longitudinal muscle layer of the rectum, the 'rectourethral (RU) muscle', extended anteriorly from the anorectal bend to the penile bulb. Fibrous tissue that formed in the inferior reach of the fetal RU muscle identified the location of the developing perineal body (PB) and divided the muscle into posterior 'rectoperineal' and anterior 'deep perineal' portions. In males, the PB remained small and bipartite, so that the RU muscle presented as an undivided midline structure. The well-developed female PB, instead, intertwined with the deep perineal muscle and both structures passed the vagina bilaterally to form the perineal membrane in the posterior portion of the urogenital triangle. The urethral rhabdosphincter extended in the anterior portion of the urogenital triangle between the penile bulb inferiorly and the bladder neck superiorly, and consisted of a well-developed circular 'membranous' portion with bilateral posteroinferior 'wings' and a thinner 'prostatic' portion on the prostate anterior side. In men, muscles occupy the urogenital triangle, but additional tightening of the locally fibrous adipose tissue by the superficial transverse perineal muscle appears necessary to generate functional support in women. An interactive 3D pdf file with these anatomical details (available online) should allow more accurate interpretation of ultrasound, computed tomography and magnetic resonance images.

A dosimetric phantom study of thoracic radiotherapy based on three-dimensional modeling of mediastinal lymph nodes.

The aim of the present study was to investigate the optimal strategy and dosimetric measurement of thoracic radiotherapy based on three-dimensional (3D) modeling of mediastinal lymph nodes (MLNs). A 3D model of MLNs was constructed from a Chinese Visible Human female dataset. Image registration and fusion between reconstructed MLNs and original chest computed tomography (CT) images was conducted in the Eclipse™ treatment planning system (TPS). There were three plans, including 3D conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT), which were designed based on 10 cases of simulated lung lesions (SLLs) and MLNs. The quality of these plans was evaluated via examining indexes, including conformity index (CI), homogeneity index and clinical target volume (CTV) coverage. Dose-volume histogram analysis was performed on SLL, MLNs and organs at risk (OARs). A Chengdu Dosimetric Phantom (CDP) was then drilled at specific MLNs according to 20 patients with thoracic tumors and of a medium-build. These plans were repeated on fused MLNs and CDP CT images in the Eclipse™ TPS. Radiation doses at the SLLs and MLNs of the CDP were measured and compared with calculated doses. The established 3D MLN model demonstrated the spatial location of MLNs and adjacent structures. Precise image registration and fusion were conducted between reconstructed MLNs and the original chest CT or CDP CT images. IMRT demonstrated greater values in CI, CTV coverage and OAR (lungs and spinal cord) protection, compared with 3D-CRT and VMAT (P<0.05). The deviation between the measured and calculated doses was within ± 10% at SLL, and at the 2R and 7th MLN stations. In conclusion, the 3D MLN model can benefit plan optimization and dosimetric measurement of thoracic radiotherapy, and when combined with CDP, it may provide a tool for clinical dosimetric monitoring.

Architectural differences in the anterior and middle compartments of the pelvic floor of young-adult and postmenopausal females.

The pelvic floor guards the passage of the pelvic organs to the exterior. The near-epidemic prevalence of incontinence in women continues to generate interest in the functional anatomy of the pelvic floor. However, due to its complex architecture and poor accessibility, the classical 'dissectional' approach has been unable to come up with a satisfactory description, so that many aspects of its anatomy continue to raise debate. For this reason, we opted for a 'sectional' approach, using the Chinese Visible Human project (four females, 21-35 years) and the Visible Human Project (USA; one female, 59 years) datasets to investigate age-related changes in the architecture of the anterior and middle compartments of the pelvic floor. The puborectal component of the levator ani muscle defined the levator hiatus boundary. The urethral sphincter complex consisted of a circular proximal portion (urethral sphincter proper), a sling that passed on the vaginal wall laterally to attach to the puborectal muscle (urethral compressor), and a circular portion that surrounded the distal urethra and vagina (urethrovaginal sphincter). The exclusive attachment of the urethral sphincter to soft tissues implies dependence on pelvic-floor integrity for optimal function. The vagina was circular at the introitus and gradually flattened between bladder and rectum. Well-developed fibrous tissue connected the inferior vaginal wall with urethra, rectum and pelvic floor. With eight-muscle insertions, the perineal body was a strong, irregular fibrous node that guarded the levator hiatus. Only loose areolar tissue comprising a remarkably well developed venous plexus connecting the middle and superior parts of the vagina with the lateral pelvic wall. The posterolateral boundary of the putative cardinal and sacrouterine ligaments coincided with the adventitia surrounding the mesorectum. The major difference between the young-adult and postmenopausal pelvic floor was the expansion of fat in between the components of the pelvic floor. We hypothesize that accumulation of pelvic fat compromises pelvic-floor cohesion, because the pre-pubertal pelvis contains very little fibrous and adipose tissue, and fat is an excellent lubricant.

In vivo evaluation of Mg-6Zn and titanium alloys on collagen metabolism in the healing of intestinal anastomosis.

There is a great clinical need for biodegradable materials, which were used as pins of circular staplers, for gastrointestinal reconstruction in medicine. In this work we compared the effects of the Mg-6Zn and the titanium alloys on collagen metabolism in the healing of the intestinal tract in vivo. The study included Sprague-Dawley rats and their effect was compared on rat's intestinal tract, using serum magnesium, radiology, and immunohistochemistry in vivo. Radiographic and scanning electron microscope evaluation confirmed the degradation by Mg-6Zn alloy during the implantation period. Biochemical measurements including serum magnesium, creatinine, blood urea nitrogen and glutamic-pyruvic-transaminase proved that degradation of Mg-6Zn alloy showed no impact on serum magnesium and the function of other important organs. Superior to titanium alloy, Mg-6Zn alloy enhanced the expression of collagen I/III and relatively suppressed the expression of MMP-1/-13 in the healing tissues, leading to more mature collagen formation at the site of anastomosis. In conclusion, Mg-6Zn alloy performed better than titanium alloy on collagen metabolism and promoted the healing of intestinal anastomosis. Hence, Mg-6Zn may be a promising candidate for use of stapler pins for intestinal reconstruction in the clinically.

Segmenting Brain Tissues from Chinese Visible Human Dataset by Deep-Learned Features with Stacked Autoencoder.

Cryosection brain images in Chinese Visible Human (CVH) dataset contain rich anatomical structure information of tissues because of its high resolution (e.g., 0.167 mm per pixel). Fast and accurate segmentation of these images into white matter, gray matter, and cerebrospinal fluid plays a critical role in analyzing and measuring the anatomical structures of human brain. However, most existing automated segmentation methods are designed for computed tomography or magnetic resonance imaging data, and they may not be applicable for cryosection images due to the imaging difference. In this paper, we propose a supervised learning-based CVH brain tissues segmentation method that uses stacked autoencoder (SAE) to automatically learn the deep feature representations. Specifically, our model includes two successive parts where two three-layer SAEs take image patches as input to learn the complex anatomical feature representation, and then these features are sent to Softmax classifier for inferring the labels. Experimental results validated the effectiveness of our method and showed that it outperformed four other classical brain tissue detection strategies. Furthermore, we reconstructed three-dimensional surfaces of these tissues, which show their potential in exploring the high-resolution anatomical structures of human brain.

An eFace-Template Method for Efficiently Generating Patient-Specific Anatomically-Detailed Facial Soft Tissue FE Models for Craniomaxillofacial Surgery Simulation.

Accurate surgical planning and prediction of craniomaxillofacial surgery outcome requires simulation of soft-tissue changes following osteotomy. This can only be accomplished on an anatomically-detailed facial soft tissue model. However, current anatomically-detailed facial soft tissue model generation is not appropriate for clinical applications due to the time intensive nature of manual segmentation and volumetric mesh generation. This paper presents a novel semi-automatic approach, named eFace-template method, for efficiently and accurately generating a patient-specific facial soft tissue model. Our novel approach is based on the volumetric deformation of an anatomically-detailed template to be fitted to the shape of each individual patient. The adaptation of the template is achieved by using a hybrid landmark-based morphing and dense surface fitting approach followed by a thin-plate spline interpolation. This methodology was validated using 4 visible human datasets (regarded as gold standards) and 30 patient models. The results indicated that our approach can accurately preserve the internal anatomical correspondence (i.e., muscles) for finite element modeling. Additionally, our hybrid approach was able to achieve an optimal balance among the patient shape fitting accuracy, anatomical correspondence and mesh quality. Furthermore, the statistical analysis showed that our hybrid approach was superior to two previously published methods: mesh-matching and landmark-based transformation. Ultimately, our eFace-template method can be directly and effectively used clinically to simulate the facial soft tissue changes in the clinical application.

3D Topography of the Young Adult Anal Sphincter Complex Reconstructed from Undeformed Serial Anatomical Sections.

BACKGROUND: Pelvic-floor anatomy is usually studied by artifact-prone dissection or imaging, which requires prior anatomical knowledge. We used the serial-section approach to settle contentious issues and an interactive 3D-pdf to make the results widely accessible. METHOD: 3D reconstructions of undeformed thin serial anatomical sections of 4 females and 2 males (21-35y) of the Chinese Visible Human database. FINDINGS: Based on tendinous septa and muscle-fiber orientation as segmentation guides, the anal-sphincter complex (ASC) comprised the subcutaneous external anal sphincter (EAS) and the U-shaped puborectal muscle, a part of the levator ani muscle (LAM). The anococcygeal ligament fixed the EAS to the coccygeal bone. The puborectal-muscle loops, which define the levator hiatus, passed around the anorectal junction and inserted anteriorly on the perineal body and pubic bone. The LAM had a common anterior attachment to the pubic bone, but separated posteriorly into puborectal and "pubovisceral" muscles. This pubovisceral muscle was bilayered: its internal layer attached to the conjoint longitudinal muscle of the rectum and the rectococcygeal fascia, while its outer, patchy layer reinforced the inner layer. ASC contraction makes the ano-rectal bend more acute and lifts the pelvic floor. Extensions of the rectal longitudinal smooth muscle to the coccygeal bone (rectococcygeal muscle), perineal body (rectoperineal muscle), and endopelvic fascia (conjoint longitudinal and pubovisceral muscles) formed a "diaphragm" at the inferior boundary of the mesorectum that suspended the anorectal junction. Its contraction should straighten the anorectal bend. CONCLUSION: The serial-section approach settled contentious topographic issues of the pelvic floor. We propose that the ASC is involved in continence and the rectal diaphragm in defecation.

New region-scalable discriminant and fitting energy functional for driving geometric active contours in medical image segmentation.

We propose a novel region-based geometric active contour model that uses region-scalable discriminant and fitting energy functional for handling the intensity inhomogeneity and weak boundary problems in medical image segmentation. The region-scalable discriminant and fitting energy functional is defined to capture the image intensity characteristics in local and global regions for driving the evolution of active contour. The discriminant term in the model aims at separating background and foreground in scalable regions while the fitting term tends to fit the intensity in these regions. This model is then transformed into a variational level set formulation with a level set regularization term for accurate computation. The new model utilizes intensity information in the local and global regions as much as possible; so it not only handles better intensity inhomogeneity, but also allows more robustness to noise and more flexible initialization in comparison to the original global region and regional-scalable based models. Experimental results for synthetic and real medical image segmentation show the advantages of the proposed method in terms of accuracy and robustness.

An effective and robust method for modeling multi-furcation liver vessel by using Gap Border Pairing.

Shape-based 3D surface reconstructing methods for liver vessels have difficulties to tackle with limited contrast of medical images and the intrinsic complexity of multi-furcation parts. In this paper, we propose an effective and robust technique, called Gap Border Pairing (GBPa), to reconstruct surface of liver vessels with complicated multi-furcations. The proposed method starts from a tree-like skeleton which is extracted from segmented liver vessel volumes and preprocessed as a number of simplified smooth branching lines. Secondly, for each center point of any branching line, an optimized elliptic cross-section ring (contour) is generated by optimizedly fitting its actual cross-section outline based on its tangent vector. Thirdly, a tubular surface mesh is generated for each branching line by weaving all of its adjacent rings. Then for every multi-furcation part, a transitional regular mesh is effectively and regularly reconstructed by using GBP. An initial model is generated after reconstructing all multi-furcation parts. Finally, the model is refined by using just one time subdivision and its topologies can be re-maintained by grouping its facets according to the skeleton, providing high-level editability. Our method can be automatically implemented in parallel if the segmented vessel volume and corresponding skeletons are provided. The experimental results show that GBP model is accurate enough in terms of the boundary deviations between segmented volume and the model.

Value of a virtual hepatic segment model in assisting in the ultrasonic localization of intrahepatic lesions.

BACKGROUND: During scanning of the right hypochondrium and right intercostal regions with an ultrasonic transducer, several ultrasonic images of oblique sections are obtained. It is still a challenge for ultrasonography to divide these non-conventional sections into an accurate hepatic segmentation pattern. The aim of this research was to investigate the value of the virtual hepatic segment model (VHSM) in assisting the ultrasonic localization of space-occupying hepatic lesions. METHODS: VHSM was constructed via 3D reconstruction according to the first Chinese visible human dataset. Preoperative ultrasonography, contrast-enhanced CT scan and VHSM techniques were performed in 100 patients with space-occupying focal lesions in the liver parenchyma for segmental localization. The results of these three techniques were compared with the operative findings. RESULTS: VHSM was successfully detected on 2D sectional images by 3D reconstruction through surface rendering and volume rendering. The model could simulate ultrasonic directions to conduct a virtual dissection on any section plane, and fine liver segmentation could be displayed in any virtual plane. In 100 patients, there were 112 liver space-occupying focal lesions distributed in 148 liver segmentations. Regarding the positioning accuracies for lesions of different sizes and the lesion segmental distribution accuracies estimated using the three methods mentioned above, ultrasonography exhibited a significantly lower accuracy than VHSM for the segmental localization of lesions (P < 0.05), and contrast-enhanced CT was not significantly different from ultrasonography plus VHSM (P > 0.05). CONCLUSION: VHSM increased the accuracy of ultrasonic localization of space-occupying hepatic lesions, particularly in hepatic hypovascular regions.

Oblique coronal view of the ACL double-bundle: Comparison of the Chinese Visible Human dataset and low-field MRI.

The aim of this study was to distinguish the individual bundles of the anterior cruciate ligament (ACL) using the Chinese Visible Human (CVH) dataset and images obtained by low-field routine magnetic resonance imaging (MRI) in the oblique and coronal planes. Sectional anatomical data of the knee were selected from the CVH dataset and reconstructed in 3D. MRI of normal knees was performed with a low-field-strength magnet in the coronal plane. The shape of the ACL was clearly displayed. Using the oblique coronal plane, the anteromedial (AM) and posterolateral (PL) bundles of the ACL were distinguished in the reconstructed anatomical data and the MR images. The double-bundle structure of the ACL was evaluated in the CVH 3D reconstructions and MR images. Using the oblique coronal plane, it was possible to review the ACL structure in the knee. The study demonstrated the feasibility of distinguishing the two bundles in the ACL with CVH 3D reconstruction and low-field strength MRI. The accuracy in the grading of ACL injury in presurgical planning may be improved.

Altered brain structural connectivity in post-traumatic stress disorder: a diffusion tensor imaging tractography study.

BACKGROUND: Post-traumatic stress disorder (PTSD) is characterized by dysfunction of several discrete brain regions such as medial prefrontal gyrus with hypoactivation and amygdala with hyperactivation. However, alterations of large-scale whole brain topological organization of structural networks remain unclear. METHODS: Seventeen patients with PTSD in motor vehicle accident survivors and 15 normal controls were enrolled in our study. Large-scale structural connectivity network (SCN) was constructed using diffusion tensor tractography, followed by thresholding the mean factional anisotropy matrix of 90 brain regions. Graph theory analysis was then employed to investigate their aberrant topological properties. RESULTS: Both patient and control group showed small-world topology in their SCNs. However, patients with PTSD exhibited abnormal global properties characterized by significantly decreased characteristic shortest path length and normalized characteristic shortest path length. Furthermore, the patient group showed enhanced nodal centralities predominately in salience network including bilateral anterior cingulate and pallidum, and hippocampus/parahippocamus gyrus, and decreased nodal centralities mainly in medial orbital part of superior frontal gyrus. LIMITATIONS: The main limitation of this study is the small sample of PTSD patients, which may lead to decrease the statistic power. Consequently, this study should be considered an exploratory analysis. CONCLUSIONS: These results are consistent with the notion that PTSD can be understood by investigating the dysfunction of large-scale, spatially distributed neural networks, and also provide structural evidences for further exploration of neurocircuitry models in PTSD.

Overexpression of synoviolin facilitates the formation of a functional synovial biomembrane.

Digital flexor tendon repair poses a significant challenge for hand surgeons. Currently, extrasynovial tendon grafts are frequently used in clinical settings to bridge flexor tendon defects. However, the healing process is always accompanied by postoperative adhesion. This is mostly due to the fact that no synovial membrane covers the extrasynovial tendon surface, in contrast to the intrasynovial tendon. In this study, we present an efficient method of developing a functional synovial biomembrane on the surface of the extrasynovial tendon. Synoviocytes were isolated from the knee joint of a Japanese white rabbit. After being infected with lentivirus, the over-expression of synoviolin in these synoviocytes was confirmed by semi-quantitative RT-PCR and western blotting. Cellular proliferation and increased hyaluronic acid secretion were confirmed in the synoviolin over-expressing synoviocytes by MTT-based method, cell cycle assays and ELISA. Furthermore, the synoviolin over-expressing synoviocytes were co-cultured with extrasynovial tendons that were harvested from the hind leg of rabbits. After being co-cultured in vitro for 3 and 7 days, these infected synoviocytes were found to accelerate the formation of a biomembrane on the tendon surface compared to the control group. More importantly, Alcian blue staining confirmed the ability of this cultured biomembrane to produce specific matrices containing acidic carboxyl mucopolysaccharides (mainly hyaluronic acid). All these results demonstrate that the over-expression of synoviolin stimulates the proliferation and HA secretion of synoviocytes and facilitates the formation of a functional synovial biomembrane.

Creation of a female and male segmentation dataset based on Chinese Visible Human (CVH).

OBJECTIVE: Segmentation is a necessary step when creating realistic three-dimensional (3D) models. In order to build 3D models of whole body structures and have a wider lateral application, the thin sectional anatomical images of the Chinese Visible Human (CVH) dataset should be segmented. The more detailed structures are segmented to provide greater potential for wider application of the segmented images. MATERIALS AND METHODS: All the images based on the CVH male and female dataset were segmented semi-automatically using PHOTOSHOP software. This research lasted about 7 years. RESULT: In this study, 869 structures of CVH male and 860 structures of CVH female were semi-automatically segmented, and the formats for the segmented color-filled image data were PSD and PNG. In these segmented structures, nearly all skeletal muscles included muscle belly and tendon, and hollow organs included their organ walls and their lumen. Most nerve trunks, small arteries, lymph nodes, and lymph ducts were also segmented. Many surface-rendering and volume-rendering organ models were created using these segmented images. CONCLUSION: The CVH male and female images represent the normal Asian population. After segmentation, the images can be reconstructed directly in 3D and greatly facilitate the biological modeling of physical and physiological information, a great help in improving medical and biological science in China.

Comparative study of thin sectional anatomical images from Chinese visible human data set and computed tomography images of superior mediastinum.

The structures of superior mediastinum and their spatial relationships are complex and difficult to master. This study aimed to compare visualization of the superior mediastinum based on computed tomography (CT) images and on the thin sections of the Chinese visible human (CVH) data set to provide a sectional anatomical basis for diagnostic imaging of superior mediastinal pathology. CVH sections of the mediastinum of a 35-year old male were compared with plain and enhanced CT images of a 45-year old male without apparent abnormalities in the upper chest. In addition, a three-dimensional model based on the CVH sections was compared with a model based on CT images. Although CT imaging is noninvasive and can be carried out in many individuals, its weakness is clearly the visualization of small soft tissue structures. In this respect, the sectional anatomical approach of the CVH images is complementary, as it visualizes these small soft tissue structures due to the higher resolution in the plain of sectioning and the color of the different structures in the section. Three-dimensional surface and volume rendering of reconstructions of the CVH data set can help medical students and less experienced thoracic surgeons to familiarize themselves with the topographic anatomy of the superior mediastinal structures and their spatial relationships, and thus with interpreting CT images of patients.