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

Three-dimensional structure of the facial canal and related blood vessels and nerves in the temporal bone

PURPOSE

There are only limited anatomical data on nerves, veins, and arteries in the temporal bone. More detailed anatomical data are required to improve planning of treatments targeting the temporal bone region. Herein, we performed a detailed analysis of the facial canal (FC) and the related carotid artery and vein.

METHODS

We examined the bony structure of the middle ear and FC, jugular foramen, and carotid canal in 30 Japanese elderly donor cadavers. Three-dimensional reconstruction of the canal structure was achieved using cone beam computed tomography, while macroscopic and histological analyses were also performed.

RESULTS

The FC form was classified as either straight (28%) or bent (72%). There were significant differences in the diameter of the FC and the distance between the internal jugular vein, other FC branches, and the FC. Principal component analysis (PCA) was performed for the FC using 29 factors. Two principal components significantly explained 30.9% (component 1, 18.6%; component 2, 12.3%) of the FC. Histological observation showed numerous ganglion cells and shrunken neurons in the geniculate ganglion of the facial nerve of elderly samples.

CONCLUSION

FC diameter is an important contributor to the relationship between the FC and the jugular foramen. The FC and the internal jugular vein are located close to each other, which is useful information for the trans-canal surgery of the otology. Furthermore, the geniculate ganglion contains numerous ganglion cells and shrunken neurons, which may affect the FC structure during bone matrix remodeling with aging.

The Creation of an Experimental Data Set Containing Coronal Section Images of a Human Head

OBJECTIVES

The aim of the research is to create an experimental data set of coronal section images of a human head.

METHODS

The head of a 49-year-old male cadaver was scanned by computed tomography (CT), then perfused with a green filling material via the bilateral common carotid artery, before being frozen and embedded. The head was sectioned along the coronal plane by a computer-controlled 5520 engraving and milling machine, capable of either 0.03-mm or 0.06-mm interspacing. All images were captured with a Canon 5D-Mk III digital camera.

RESULTS

A total of 3854 section images were obtained, each with a resolution of 5760 × 3840 pixels. The number of section images at 0.03- and 0.06-mm interspacing were 1437 and 2417, respectively. All the images were stored in JPG and RAW formats. The image size of each RAW format was about 24.5 MB, whereas for JPG format, the equivalent size was about 5.9 MB. All the RAW and JPG images together occupied 117.35 GB of disk space.

CONCLUSIONS

The interspacing of this data set section was thinner than those of any comparable studies, and the image resolution was higher, too. This data set was also the first to take coronal sections of the human head. The data set contains image information from the smallest structures within the human head and can satisfy the needs of future developments and applications, such as the virtual operation training systems for otolaryngology, ophthalmology, stomatology, and neurosurgery, and help develop medical teaching software and maps.

Web-based imaging viewer for real-color volumetric reconstruction of human visible project and DICOM datasets

Anatomy remains a cornerstone of medical education. It is vital that students achieve a robust understanding of the spatial relationships between anatomical structures in three dimensions. Volumetric medical imaging studies and true-color cryosectional three-dimensional images of visible human datasets are useful for enhancing anatomy education. However, the software systems available for viewing these datasets have important limitations. A web-based application called Mulrecon Color, which can overcome a number of those limitations, is introduced. Mulrecon Color enables volumetric medical and full color cryosectional datasets to be explored without requiring installation, and can therefore be used on a broad range of desktop, mobile, and even virtual reality devices. The web-based application has an interface that resembles a DICOM viewer used in radiological practice, and can be used both in anatomical labs and off campus for self-study. The Mulrecon Color application is released as an open source tool. It can be retrieved at a project website where sample datasets are also available.

Averaged head phantoms from magnetic resonance images of Korean children and young adults

Increased use of mobile phones raises concerns about the health risks of electromagnetic radiation. Phantom heads are routinely used for radiofrequency dosimetry simulations, and the purpose of this study was to construct averaged phantom heads for children and young adults. Using magnetic resonance images (MRI), sectioned cadaver images, and a hybrid approach, we initially built template phantoms representing 6-, 9-, 12-, 15-year-old children and young adults. Our subsequent approach revised the template phantoms using 29 averaged items that were identified by averaging the MRI data from 500 children and young adults. In females, the brain size and cranium thickness peaked in the early teens and then decreased. This is contrary to what was observed in males, where brain size and cranium thicknesses either plateaued or grew continuously. The overall shape of brains was spherical in children and became ellipsoidal by adulthood. In this study, we devised a method to build averaged phantom heads by constructing surface and voxel models. The surface model could be used for phantom manipulation, whereas the voxel model could be used for compliance test of specific absorption rate (SAR) for users of mobile phones or other electronic devices.

Preoperative preparation for otologic surgery: temporal bone simulation

PURPOSE OF REVIEW

The field of temporal bone simulation (TBS) has largely focused on the development and validation of simulators as training and assessment tools. As technology has progressed over the years, researchers have, however, envisioned new clinical applications for simulators extending to preoperative surgical planning and case rehearsal. The purpose of this article was to review the current state of the art in TBS and to highlight recent advancements in the field. Because of space limitations, we will limit our discussion to computer-based virtual reality simulators.

RECENT FINDINGS

A review of the recent literature on TBS revealed very limited application of virtual reality simulators for preoperative preparation. Current evidence suggests limitations in fidelity preclude successful patient-specific case rehearsal using virtual reality simulation. Further investigation and clinical evaluation are required to validate its use outside of training and skill assessment.

SUMMARY

This article provides an overview of the current use of virtual reality simulators with emphasis on preoperative planning. We evaluate the limitations of the technology, and discuss potential areas of improvement for the future. More studies are necessary to assess the value of virtual reality simulation for preoperative preparation.