Visualization of the temporal bone of the Chinese Visible Human

Comparative study of female pelvic floor among undeformed high-resolution thin-sectional anatomical (visible human) images and MRI and ultrasound images

PURPOSE

Using visible human, MRI and ultrasound images, we aim to provide an anatomical basis for the identification and diagnosis of pelvic floor structure and disease by ultrasound imaging.

METHODS

One Chinese visible human (CVH) image, one American visible human image, 9 MRI images of normal volunteers, and 40 ultrasound images of normal volunteers or pelvic organ prolapse patients were used. Pelvic organs, pelvic floor muscles, and the connective tissue in CVH, VHP, MRI, and ultrasound images were selected for comparative study.

RESULTS

We successfully identified the boundary of the anal sphincter complex, including the subcutaneous, superficial, and deep parts of the external anal sphincter, conjoined longitudinal muscles and internal anal sphincter; the levator ani muscle (LAM), including the internal and external parts of the pubovisceral muscle and the superficial and deep parts of the puborectal muscle; the urethral sphincter complex, including the urethral sphincter proper and the urethral compressor; and the perineal body, the rectoperineal muscle and superficial transverse perineal muscle.

CONCLUSIONS

We successfully recognized and studied the location, subdivisions, 2D morphology and spatial relationships of the LAM, anal sphincter complex, urethral sphincter complex and perineal body in ultrasound images, thereby helping sonologists or clinicians accurately identify pelvic floor muscles and supporting structures in ultrasound images.

3D-Printed Models for Temporal Bone Surgical Training: A Systematic Review

OBJECTIVE

3D-printed models hold great potential for temporal bone surgical training as a supplement to cadaveric dissection. Nevertheless, critical knowledge on manufacturing remains scattered, and little is known about whether use of these models improves surgical performance. This systematic review aims to explore (1) methods used for manufacturing and (2) how educational evidence supports using 3D-printed temporal bone models.

DATA SOURCES

PubMed, Embase, the Cochrane Library, and Web of Science.

REVIEW METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, relevant studies were identified and data on manufacturing and validation and/or training extracted by 2 reviewers. Quality assessment was performed using the Medical Education Research Study Quality Instrument tool; educational outcomes were determined according to Kirkpatrick's model.

RESULTS

The search yielded 595 studies; 36 studies were found eligible and included for analysis. The described 3D-printed models were based on computed tomography scans from patients or cadavers. Processing included manual segmentation of key structures such as the facial nerve; postprocessing, for example, consisted of removal of print material inside the model. Overall, educational quality was low, and most studies evaluated their models using only expert and/or trainee opinion (ie, Kirkpatrick level 1). Most studies reported positive attitudes toward the models and their potential for training.

CONCLUSION

Manufacturing and use of 3D-printed temporal bones for surgical training are widely reported in the literature. However, evidence to support their use and knowledge about both manufacturing and the effects on subsequent surgical performance are currently lacking. Therefore, stronger educational evidence and manufacturing knowhow are needed for widespread implementation of 3D-printed temporal bones in surgical curricula.

Operative Anatomy of the Human Skull: A Virtual Reality Expedition

INTRODUCTION

The human cranial vault possesses an incredible, complex anatomical intricacy. Bridging the divide between 2-dimensional (2D) learning resources and the 3-dimensional (3D) world in which the anatomy becomes clinically relevant poses an intellectual challenge. Advances in computer graphics and modelling technologies have allowed increasingly accurate and representative resources to supplement cadaveric dissection specimens.

OBJECTIVE

To create accurate virtual models of all cranial bones to augment education, research, and clinical endeavours.

METHODS

Through a careful analysis of osteological specimens and high-resolution radiographic studies, a highly accurate virtual model of the human skull was created and annotated with relevant anatomical landmarks.

RESULTS

The skull was divided into 6 major segments including frontal, ethmoid, sphenoid, temporal, parietal, and occipital bones. These bones were thoroughly annotated to demonstrate the intricate anatomical features.

CONCLUSION

This virtual model has the potential to serve as a valuable resource for educational, research, and clinical endeavours, and demonstrates the significance of advances in computer modelling that can contribute to our understanding of neurosurgical anatomical substrates.

A Comprehensive Review of Medical Imaging Equipment Used in Cadaveric Studies

Medical imaging techniques have led to great advances in clinical anatomy and forensic pathology. New and emerging technologies allow healthcare professionals to view and understand the human body from different perspectives. This gives way to new and improved interventions, treatment plans, and an overall understanding of the human body. Herein, we present a comprehensive review of the various medical imaging equipment used in cadaveric studies along with their individual strengths and limitations.

Establishing a Temporal Bone Laboratory in Teaching Institutes to Train Future Otorhinolaryngologists and Fundamentals of Temporal Bone Laboratory: Considerations and Requirements

Temporal bone dissection has important role in educating, and training the surgeons. Temporal bone has complicated three dimensional anatomy and it is challenging for young surgeons to understand and operate. Not knowing the anatomy may cause serious consequences to patient due to injury to vital structures. It is important to learn temporal bone harvesting techniques, preservation of specimens, fixation and to reduce the health hazards posed by these specimens by taking safety measures. Spending more time in temporal bone laboratory and repeated dissection of temporal bones provides the skills necessary in the operating room for future generation. All training institutes should establish temporal bone laboratory in their department to provide the necessary expertise to future generation while maintaining safe and secure environment.

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.

Digital three-dimensional model of lumbar region 4-5 and its adjacent structures based on a virtual Chinese human

OBJECTIVE

To study the methods for constructing a digitized three-dimensional (3D) model of a virtual lumbar region and its adjacent structures in order to assist anatomical study and virtual surgery.

METHODS

Images of DSCF5375-p1 to DSCF5745-p1 were taken from the database of the digitized Virtual Chinese human of Southern Medical University in Guangzhou. This region encompasses the superior facet joint of L4 to the inferior edge of the intervertebral body of L5. The regions of interest were interactively segmented from the images utilizing Adobe Photoshop software. The images were further processed using format conversion and segmentation. Finally, a 3D model of the L4-5 region and its neighboring structures was reconstructed with the assistance of Mimics 10.01 software.

RESULTS

A digitized 3D model of this part of the virtual lumbar spine and its adjacent structures was reconstructed. This model allows all constructed structures to be displayed individually or jointly, moved or rotated arbitrarily, setting of different transparencies and convenient measurement of the diameters and angles of the reconstructed structures. The 3D model precisely displays the anatomical relationships between all structures and provides a reliable 3D model for a spinal endoscopic surgery simulation system.

CONCLUSION

Visualization of the digitized 3D reconstruction of the virtual lower lumbar region displays this region and its adjacent structures stereoscopically and in actuality, thus providing morphological data concerning anatomy, image diagnosis and virtual operations in this region.

Freely-available, true-color volume rendering software and cryohistology data sets for virtual exploration of the temporal bone anatomy

BACKGROUND

Cadaveric dissection of temporal bone anatomy is not always possible or feasible in certain educational environments. Volume rendering using CT and/or MRI helps understanding spatial relationships, but they suffer in nonrealistic depictions especially regarding color of anatomical structures. Freely available, nonstained histological data sets and software which are able to render such data sets in realistic color could overcome this limitation and be a very effective teaching tool.

METHODS

With recent availability of specialized public-domain software, volume rendering of true-color, histological data sets is now possible. We present both feasibility as well as step-by-step instructions to allow processing of publicly available data sets (Visible Female Human and Visible Ear) into easily navigable 3-dimensional models using free software.

RESULTS

Example renderings are shown to demonstrate the utility of these free methods in virtual exploration of the complex anatomy of the temporal bone. After exploring the data sets, the Visible Ear appears more natural than the Visible Human.

CONCLUSION

We provide directions for an easy-to-use, open-source software in conjunction with freely available histological data sets. This work facilitates self-education of spatial relationships of anatomical structures inside the human temporal bone as well as it allows exploration of surgical approaches prior to cadaveric testing and/or clinical implementation.

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.

Cholesteatoma in three dimensions: a teaching tool and an aid to improved pre-operative consent

Background:

Otological surgeons face two recurring challenges. Firstly, we must foster an appreciation of the complex, three-dimensional anatomy of the temporal bone in order to enable our trainees to operate safely and independently. Secondly, we must explain to our patients the necessity for surgery which carries the potential for serious complication.

Methods:

Amira® software was applied to pre-operative computed tomography images of temporal bones with cholesteatoma, to create three-dimensional computer images. Normal structures and cholesteatoma were displayed in a user-friendly, interactive format, allowing both trainee and patient to visualise disease and important structures within the temporal bone.

Results:

Three cases, and their three-dimensional computer models are presented. Zoom, rotation and transparency functions complemented the three-dimensional effect.

Conclusion:

These three-dimensional models provided a useful adjunct to cadaveric temporal bone dissection and surgical experience for our residents' teaching programme. Also, patients with cholesteatoma reported a better understanding of their pre-operative condition when the models were used during the consenting process.

VIRTUAL TEMPORAL BONE: AN INTERACTIVE 3‐DIMENSIONAL LEARNING AID FOR CRANIAL BASE SURGERY

OBJECTIVE

We have developed an interactive virtual model of the temporal bone for the training and teaching of cranial base surgery.

METHODS

The virtual model was based on the tomographic data of the Visible Human Project. The male Visible Human's computed tomographic data were volumetrically reconstructed as virtual bone tissue, and the individual photographic slices provided the basis for segmentation of the middle and inner ear structures, cranial nerves, vessels, and brainstem. These structures were created by using outlining and tube editing tools, allowing structural modeling either directly on the basis of the photographic data or according to information from textbooks and cadaver dissections. For training and teaching, the virtual model was accessed in the previously described 3-dimensional workspaces of the Dextroscope or Dextrobeam (Volume Interactions Pte, Ltd., Singapore), whose interfaces enable volumetric exploration from any perspective and provide virtual tools for drilling and measuring.

RESULTS

We have simulated several cranial base procedures including approaches via the floor of the middle fossa and the lateral petrous bone. The virtual model suitably illustrated the core facts of anatomic spatial relationships while simulating different stages of bone drilling along a variety of surgical corridors. The system was used for teaching during training courses to plan and discuss operative anatomy and strategies.

CONCLUSION

The Virtual Temporal Bone and its surrounding 3-dimensional workspace provide an effective way to study the essential surgical anatomy of this complex region and to teach and train operative strategies, especially when used as an adjunct to cadaver dissections.

The thin sectional anatomy of the temporal bone correlated with multislice spiral CT

The aim of this study was to explore the method for obtaining the thin sectional anatomy data of the adult temporal bone and study the fine structures using this method. Three fresh adult cadaveric heads were scanned with multi-slice computer tomography (MSCT) centered on petrous bones. The CT images of 0.6 mm were obtained by multi-planar reformation (MPR). The slices of 0.1 mm were shaved off the specimen in the axial direction with the numerical control milling machine after being embedded and frozen, pictures of which were taken by the digital camera and saved in the computer. The thin axial sectional anatomic structures of the intra-temporal were investigated and correlated with MPR images. Via the comparison, fifty micro-anatomic structures of the temporal bone that can't be delineated clearly or missed in the thick sections were evaluated. The anatomical details of the temporal bone can be clearly delineated in MSCT in sub-millimeter and were identical to those in sectional anatomy images. This method can supply anatomical details that had been missed or overlooked for imaging diagnosis and surgical anatomy.

Construction of a three-dimensional interactive model of the skull base and cranial nerves

OBJECTIVE

The goal was to develop an interactive three-dimensional (3-D) computerized anatomic model of the skull base for teaching microneurosurgical anatomy and for operative planning.

METHODS

The 3-D model was constructed using commercially available software (Maya 6.0 Unlimited; Alias Systems Corp., Delaware, MD), a personal computer, four cranial specimens, and six dry bones. Photographs from at least two angles of the superior and lateral views were imported to the 3-D software. Many photographs were needed to produce the model in anatomically complex areas. Careful dissection was needed to expose important structures in the two views. Landmarks, including foramen, bone, and dura mater, were used as reference points.

RESULTS

The 3-D model of the skull base and related structures was constructed using more than 300,000 remodeled polygons. The model can be viewed from any angle. It can be rotated 360 degrees in any plane using any structure as the focal point of rotation. The model can be reduced or enlarged using the zoom function. Variable transparencies could be assigned to any structures so that the structures at any level can be seen. Anatomic labels can be attached to the structures in the 3-D model for educational purposes.

CONCLUSION

This computer-generated 3-D model can be observed and studied repeatedly without the time limitations and stresses imposed by surgery. This model may offer the potential to create interactive surgical exercises useful in evaluating multiple surgical routes to specific target areas in the skull base.

Chinese visible human project

Research on the digital visible human is of great significance and has considerable application value. The US visible human project created the first digital image dataset of a complete human (one male and one female) in 1995. To promote worldwide application-oriented visible human research, additional visible human datasets, representative of different populations of the world, are needed. The Chinese visible human (CVH) male (created in October 2002) and female (created in February 2003) Project achieved greater integrity of images, better blood vessel identification, and were free of organic disease. The most noteworthy technical advance of the Chinese visible human project (CVHP) was the construction of a low temperature laboratory, which prevented loss of small structures (including teeth, nasal conchae, and articular cartilage) from the milling surface. Thus, better integrity of images was achieved. To date, we have acquired five CVH datasets and volume rendered them for visualization on a PC. 3D reconstruction of some organs and structures has been completed and work to segment a complete dataset is under way. Although there is still a long way to go to make the visible human meet the application-oriented needs in various fields, progress is being made toward acquiring new datasets, performing segmentation, and setting up a platform of computer-assisted medicine. Here, we review the history and highlights of the CVHP and foresee its future development as well.