Accessible and Informative Sectioned Images and SurfaceModels of a Cadaver Head

Dong Sun Shin, PhD,* Hae Gwon Jang, MS,Þ Jin Seo Park, PhD,þ Hyung Seon Park, PhD,§Sangho Lee, PhD,§ and Min Suk Chung, MD, PhD*

Abstract: The sectioned images and surface models of a cadaverhead in the Visible Korean Project would be more beneficial if theywere accessible and informative. To this aim, 3 policies wereestablished: (1) the data are promptly obtainable and observable; (2)the graphic data are accompanied by explaining the anatomic terms;and (3) two-dimensional images and three-dimensional models areshown together. According to the policies, the following wereattempted. Two hundred thirty-five couples of sectioned images andoutlined images (intervals, 1 mm) of the head were prepared.Browsing software was developed where the 2 corresponding imageswere displayed simultaneously. In addition, the structures in theimages were recognized with the aid of automatic labeling. From theoutlined images, surface models of 178 head structures were con-structed. The two-dimensional surface models including the sec-tioned images were embedded into the three-dimensional surfacemodels. All the models were categorized into systems and arrangedto be inputted to a PDF (portable document format) file. The fi-nalized PDF file containing comprehensive head data could be ex-plored on Adobe Reader. If the user clicked on the surface models,their anatomic names were highlighted. The sectioned images,outlined images, and surface models in the browsing software andPDF file can be downloaded from the homepage (anatomy.co.kr) freeof charge. The state-of-the-art graphic information will hopefullyassist medical students in learning head anatomy. In addition, the rawdata are expected to contribute to the various clinical practicesimulations.

Key Words: Anatomic models, computer-assisted imageprocessing, head, neuroanatomy, three-dimensional imaging,user-computer interface, visible human projects

(J Craniofac Surg 2012;23: 1176Y1180)

In the Visible Korean Project, sectioned images and surface modelsof the head have been created as follows. The head of a male ca-

daver was serially sectioned and photographed to provide the sec-tioned images. Outlines of different structures were drawn on thesectioned images at 1-mm intervals.1,2 The contours of each structurewere stacked in sequence, and a surface reconstruction was thenexecuted to build a surface model.3Y5

The sectioned images, outlined images, and surface modelsthat correspond with one another would be more valuable if theywere more user-friendly and instructive. To that end, 3 policies havebeen set up: (1) the image data in reduced resolution can bedownloaded from a homepage to be readily observed; (2) the sec-tioned images and surface models are automatically labeled withthe structures’ names; and (3) two-dimensional images and three-dimensional models are mixed for display.

According to the principles, we already released the softwarethat can be used to browse the sectioned images and accompanyingoutlined images of the entire male body. A small problem in theprogram is that setup files and update files have to be downloadedand installed separately.6 This problem could be alleviated by uni-fying 2 kinds of files in terms of the head data.

Surface models of various structures from different cadavershave been built and distributed. The data can be opened using only athree-dimensional viewer such asMaya version 2012 (Autodesk, Inc,San Rafael, CA). The use of this viewer is undesirable because itis expensive to acquire and complicated for the typical users to installand handle.4,5,7Y11 To overcome this problem, we decided to useAdobe Reader Windows version 9 (Adobe Systems, Inc, San Jose,CA), a free software package where our surface models, collected ina portable document format (PDF) file, could be easily manipulated.It was also decided to make the surface models capable of beingoverlapped by their raw data and sectioned images and to make allmodels linked with their anatomic terms.

The purpose of this research was to make the sectioned im-ages and surface models of cadaver head accessible and informa-tive. Our intent was to create a system that would allow the user toexplore the two- and three-dimensional data on the browsing soft-ware and Adobe Reader, respectively, to study the topographicanatomy of the head including the brain. It is hoped that interestedresearchers will evaluate the complete data, with the aim of im-proving the educational software and/or the virtual reality simulator.

MATERIALS AND METHODS

Sectioned Images and Outlined ImagesOur research team had already produced the sectioned images

and outlined images of a head from a male cadaver (67 years oldat the time of death from myasthenia gravis; height, 1.62 m; weight,45 kg). The cadaver head was serially sectioned by means of acryomacrotome to generate sectioned images (intervals, 0.1 mm;pixel size, 0.1 mm; color depth, 48-bit color; file format, TIFF

ANATOMICAL STUDY

1176 The Journal of Craniofacial Surgery & Volume 23, Number 4, July 2012

From the *Department of Anatomy, School of Medicine, and †GraduateSchool of Information and Communication, Ajou University, Suwon;‡Department of Anatomy, Dongguk University College of Medicine,Gyeongju; and §Korea Institute of Science and Technology Information,Daejeon, Republic of Korea.

Received February 7, 2012.Accepted for publication March 17, 2012.Address correspondence and reprint requests to Dr. Min Suk Chung,

Department of Anatomy, Ajou University School of Medicine,164 Worldcup-ro, Suwon, Republic of Korea, 443-749;E-mail: dissect@ajou.ac.kr

This research was supported by Basic Science Research Program throughthe National Research Foundation of Korea funded by the Ministryof Education, Science and Technology (grant no. 2010-0009950).

The authors report no conflicts of interest.Copyright * 2012 by Mutaz B. Habal, MDISSN: 1049-2275DOI: 10.1097/SCS.0b013e31825657d8

Copyright © 2012 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.

[tagged image file format]). The sectioned images comprising thebrain and adjacent cranium were compiled to generate coronal andsagittal images to satisfying neuroanatomy interest.1

In every 10 sectioned images (intervals, 1 mm), 231 structureswere delineated semiautomatically or manually on Photoshop CS3version 10 (Adobe Systems) to produce outlined images. All outlinesof each structure were filled with a specific color (color depth, 8-bitcolor; file format, BMP [bitmap]).1,3,4

Browsing Software of Two-Dimensional ImagesTwo hundred thirty-five pairs of sectioned images and out-

lined images with 1-mm intervals were prepared. The resolution ofall images was decreased to be 1000 � 997 to lower their file size.The images before and after reducing resolution represented full andreduced data, respectively (Figs. 1A, B).

The software was developed to browse the sectioned andoutlined images in the C# language of Microsoft Visual Studio .NET2003 (Microsoft Corp, Seattle, WA).6

The browsing software including all data was transformedinto an installation file on the NSIS (Nullsoft Scriptable InstallSystem; NSIS Media), a script language. NSIS was easily handledwith HM NIS Edit, a kind of user interface, by us, even with noknowledge of the computer language. Both software packages areobtainable at no cost.

Surface ModelsAmong the 231 outlined structures, 178 had been constructed

at the time of submission (Table 1). Mimics version 10.01 (Mate-rialise, Leuven, Belgium) recognized and clustered the serial outlinesof each structure considering the brightness of the designated colors.After stacking the outlines, surface reconstruction of all structureswas simultaneously achieved.12Y16

The surface models were painted individually or by systemsto distinguish the collective structures (Table 1). The color of skinwas made semitransparent to show inside (Fig. 2).

In each surface model, the outlines were removed, and tri-angular surfaces were appropriately reduced in number. Inadequatesurface models, resulting from incorrect demarcation, were revisedby anatomists.4,7,17

To further reduce the file size, the number of triangular sur-faces was decreased as far as possible without altering the originalshape of the models. For very complicated structures (eg, temporalbone), the decreased surface triangulation was very slight. The sur-face models before and after this simplification were named fulldata and reduced data, in that order (Figs. 1C, D). File format ofthe composites of the reduced data was converted from Mimics tostereolithography to be readable on the Maya software.

FIGURE 1. Full data (A, C) and reduced data (B, D) of the sectionedimage (A, B) and surface model with mesh revealed (C, D).

TABLE 1. 178 Structures That Were Surface Reconstructed Among 231 Outlined Ones

Systems Structures

Integumentary (2) Skin*

Muscular (44) Masseter,* lateral pterygoid muscle,* medial pterygoid muscle,* longus colli,* longus capitis,* sternocleidomastoid muscle,*rectus capitis posterior major,* rectus capitis posterior minor,* rectus capitis anterior,* rectus capitis lateralis,* obliquuscapitis superior,* obliquus capitis inferior,* digastric muscle,* stylohyoid muscle,* mylohyoid muscle,* sternohyoid muscle,*longissimus,* trapezius ,* levator scapulae,* thyrohyoid muscle,* splenius capitis,* semispinalis cervicis*

Skeletal (10) Cranium without mandible,* mandible, hyoid bone, first cervical vertebra, second cervical vertebra, third cervical vertebra,fourth cervical vertebra, fifth cervical vertebra, sixth cervical vertebra

Articular (4) Intervertebral disc (C IIYC III), intervertebral disc (C IIIYC IV), intervertebral disc (C IVYC V), intervertebral disc (C VYC VI)

Vascular (artery) (18) Common carotid artery,* external carotid artery,* superficial temporal artery,* maxillary artery,* internal carotid artery,*vertebral artery,* anterior cerebral artery, pericallosal artery, middle cerebral artery, posterior communicating artery, posteriorcerebral artery, basilar artery

Vascular (vein) (22) Internal jugular vein,* transverse sinus,* sigmoid sinus,* inferior petrosal sinus,* superior petrosal sinus,* emissary vein,*confluence of sinuses, occipital sinus, superior sagittal sinus, inferior sagittal sinus, straight sinus, cavernous sinus, diploic vein,superior cerebral vein, inferior cerebral vein, great cerebral vein

Sensory (eye) (18) Cornea and sclera,* lens,* levator palpebrae superioris,* superior rectus,* inferior rectus,* medial rectus,* lateral rectus,* superioroblique muscle,* inferior oblique muscle*

Sensory (ear) (18) External acoustic meatus,* stapes,* incus,* malleus,* auditory tube,* cochlea,* anterior semicircular duct,* posterior semicircularduct,* lateral semicircular duct*

Central nervous (22) Substantia nigra,* red nucleus,* thalamus,* cerebral hemisphere,* lateral ventricle,* caudate nucleus,* putamen,* globus pallidus,*spinal cord, brainstem, fourth ventricle, cerebellum, corpus callosum, fornix

Peripheral nervous (19) Optic nerve,* oculomotor nerve,* ophthalmic nerve,* frontal nerve,* chorda tympani,* abducens nerve,* facial nerve,* vestibularnerve,* cochlear nerve,* optic chiasm

Endocrine (1) Pituitary gland

Numbers in parentheses are numbers of structures.*Both bilateral structures were surface reconstructed.

FIGURE 2. Surface models of the right head with serial layers removed.Surface models are artificially painted and the skin color is made semitransparent.

The Journal of Craniofacial Surgery & Volume 23, Number 4, July 2012 Surface Models of a Cadaver Head

* 2012 Mutaz B. Habal, MD 1177

Copyright © 2012 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.

Maya was used to open the three-dimensional surface models(reduced data), into which serial two-dimensional surface modelsincluding the sectioned images were embedded. For this, horizon-tal, coronal, and sagittal sectioned images were chosen at 10-mmintervals in advance. We then elaborated two-dimensional surfacemodels that were the planes with no thickness and wrapped theprepared sectioned images on the models (Fig. 3).18 All files ofmatching three- and two-dimensional surface models were savedas stereolithography.

PDF File of Two- and Three-DimensionalSurface Models

On the Deep Exploration Standard (Right Hemisphere, SanRamon, CA), the surface models were categorized into 11 systems.In each system, some of the models were divided into right and leftsides, and the models were arranged in official anatomic terms(Table 1).19 The two-dimensional surface models comprising sec-tioned images were regarded as other systems during this task. Afterfinishing the coordination, all models were gathered in 1 VRML(virtual reality modeling language) file.

By use of the 3D Reviewer software accompanying Acrobat9.0 Pro Extended (Adobe Systems), the VRML file was inputted toa PDF file.20 When the PDF file was opened on Adobe Reader,the systematized anatomic terms of the surface models were dis-played in the left top (model tree window) (Fig. 4A), and surfacemodels were exhibited to the right (Fig. 4C).

It was advantageous to anatomy learning that the modelswere assembled according to dissection levels. So, in Acrobat, wecreated bookmarks of the PDF file. The bookmarks were as follows:all structures (oblique view), half (left) removed, skin removed,muscles removed, bones removed, blood vessels removed, eyes andears removed, and cerebral hemisphere removed (Figs. 2 and 4B).

Using Acrobat, we attached the published articles explain-ing the sectioned images and surface models of male head. In thePDF files, page 1 was already occupied by all surface models, so thearticles were put into the remaining pages (Fig. 5).

RESULTSThe installation file (Browsing software [male head]; size,

93 MB) and PDF file (PDF file [male head]; size, 83 MB) that wereconstructed are freely available at the homepage of the Department

of Anatomy at Ajou University School of Medicine (anatomy.co.kr).The files can be downloaded without charge or registration.

Browsing Software of Two-Dimensional ImagesImplementation of the installation file resulted in automatic

production of the main folder including executing file as well asthe 2 subfolders containing sectioned images and outlined images.The sectioned and outlined images (reduced data) could be used fordiverse achievements by others. If no longer needed, entire foldersand files could be erased by the uninstallation procedure.

The browsing software consisted of a tool bar for selectingimages in the left side and a couple of images in the right side.Among the 2 images, one was larger; the sizes of the images couldbe interchanged by dragging the mouse (Fig. 6).

Using the software, images could be easily browsed in realtime. The user was able to select the images either by using thescroll bar or by typing an image number into the program. Theneighboring images were continuously displayed by clicking soft-ware tools (Fig. 6).

The software images showed names of the outlined struc-tures. If a user located the mouse pointer on a structure in the out-lined images, its name appeared as the tool tip text beside the mousepointer. The structures’ names could be seen even in the sectionedimages (Fig. 6).

PDF File of Two- and Three-DimensionalSurface Models

Surface models in the PDF filewere explored on Adobe Readeras follows. Users were capable of mixed display of three-dimensionalsurface models using the check boxes of the systems and individ-ual structures (Fig. 7; Table 1). Two-dimensional surface models of

FIGURE 4. PDF file, composed of the model tree window (A), bookmarkwindow (B), and surface models (C).

FIGURE 6. Browsing software displaying structure name when the mousepointer flies over a specific structure on the outlined image (A) and the sectionedimage (B).

FIGURE 7. Highlighting of the surface models ‘‘cerebellum’’ (A), ‘‘centralnervous system’’ (B), ‘‘all structures’’ (C) by repeated mouse clicking,which coincides with highlighting of their texts in the model tree window.

FIGURE 3. Horizontal, coronal, and sagittal sectioned images, superimposedon the surface models. FIGURE 5. Paper introducing the surface models, involved in other pages

of the PDF file.

Shin et al The Journal of Craniofacial Surgery & Volume 23, Number 4, July 2012

1178 * 2012 Mutaz B. Habal, MD

Copyright © 2012 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.

sectioned images in horizontal, coronal, and sagittal planes could beexhibited too as if they were items of the other 3 systems. As a result,it was possible to superimpose the sectioned images on the three-dimensional surface models (Fig. 3). The established bookmarksenabled users to see the surface models with sequential structuresremoved (Fig. 2).

The surface models could be suitably zoomed in and zoomedout. They were freely rotated and shifted. The colors of surfacemodels, already decided by developers, might become semitrans-parent to demonstrate the behind models. Besides, toolbar ofthe Adobe Reader was available for diverse expositions of thesurface models.

If the user clicked a model, its anatomic name was high-lighted in the model tree window. The second, third, and fourth clicksof the same model resulted in spotlight of larger and larger groupsinvolving the structure, until all the systems of the head were se-lected. Reverse highlighting was possible as well; clicking inter-esting texts in the model tree window prompted the appearance ofthe matching surface models individually or by system (Fig. 7). Thesupplementary article reprints in the presented PDF file could bedemonstrated by picking the different pages (Fig. 5).

Using Acrobat, the surface models (reduced data) could beextracted from the PDF file to another three-dimensional viewer soft-ware. This was possible because the authors did not use the protec-tion option during the procedure to put surface models in PDF fileon 3D Reviewer. Locational relationship of the adjacent structureswas conserved after taking out the individual surface models of thePDF file.

DISCUSSIONThe current research aimed to make the sectioned images

and surface models of the head generated as part of the VisibleKorean Project accessible and informative. For that, 3 policies wereestablished.

The first policy is that the data have to be readily obtainablefrom a homepage and observable without difficulty. This policy wasfulfilled by downloading the sectioned images and surface modelsfor viewing on the special software and Abode Reader, respectively.Resolution of the illustrations was reduced for easy distribution andfast monitoring. The reduced data are still interpretable by medicalstudents (Fig. 1)6,7 and can be extracted from the browsing softwareand PDF file to be evaluated by other researchers. They will be sup-plied with the full data of sectioned images, outlined images, andsurface models after agreement process with authors. Our persistinggoal is the wide distribution of Visible Korean data. It is hoped thatthe complete version could be a rich information resource for use invirtual reality for medical students and clinicians.

The second policy is that the graphic data are explained byannotation. Without labels, the two-dimensional images and three-dimensional models are merely fancy pictures and not a rich sourceof learning. Automatic annotation is accomplished using the out-lined images. A structure’s name becomes visible according to thelocation of the mouse pointer either on the outlined images or onthe corresponding sectioned images. This labeling is realized by

programming based on the fact that the computer identifies thespecific colors, with which the individual structures are filled(Fig. 6).6 Computerized annotation is feasible in the PDF file for-mat. Highlighting of surface models and texts coincides with eachother (Fig. 7). This function facilitates the advantageous acquisi-tion of anatomy knowledge indeed. The surface models are builtfrom the outlined images, so delineation is regarded as the crucialmeans for the computerized annotation in both two-dimensionalimages and three-dimensional models.

The third policy is that the two-dimensional images and three-dimensional models from the identical subject are displayed to-gether. The combined demonstration is required because the sec-tioned images provide users with comprehensive information ofthe surface models. Conversely, the stereoscopic surface modelshelp users grasp the complicated sectioned images. In the PDF file,not only the horizontal sectioned images but also the coronal and sag-ittal ones are overlapped in the three-dimensional models (Fig. 3).A potential merit is that the sectioned images may be replacedwith the equivalent outlined images.1 Among the innumerable com-binations of the two-dimensional images and three-dimensionalmodels, suitable selections are required as an anatomic learningtool. For example, a student can produce the best mixture of two-and three-dimensional resources to account for magnetic resonanceimages showing caudate nucleus, lentiform nucleus, and thalamus(Fig. 8). Even without the two-dimensional images, the PDF file canbe used by students to make the best scene for explaining a givensubject (eg, morphology of the dural venous sinuses in the skull)(Fig. 9).

In terms of the combination, the browsing software com-pensates two-dimensional images in the PDF file. In the software,the sectioned images in high resolution can be seen at 1-mm inter-vals rather than at 10-mm intervals. The software is equipped withthe outlined images of 231 structures rather than 178 reconstructedstructures.6

Despite this exciting beginning, improvements of the brows-ing software and PDF file are possible. First, the more detailedstructures are delineated, the better will be the rendering of the out-lined images and surface models. The high-quality sectioned imageshave already been published in an atlas, where thousands of brainconstituents are annotated. On the basis of the extraordinarily detailedannotation in the book, someone might attempt additional delinea-tion and surface reconstruction for one’s own intention.21

Second, full versions of two- and three-dimensional datawill enable better visualization. We used a reduced version of sec-tioned image with lower resolution and surface models with fewerpolygons (Fig. 1). In addition, original intervals (0.1 mm) of thesectioned images were increased to 1 mm in the browsing softwareand even to 10 mm in the PDF file. The restriction would naturallydisappear by further improvement of the computer and communication.

Third, the browsing software and PDF file can be com-bined into 1 program containing all two-dimensional images, three-dimensional models, and satisfactory tools for user convenience. Toachieve this goal, well-organized programming after collection ofthe client demands is required.

The sectioned images, outlined images, and surface modelsof male head in the browsing software and PDF file will hopefully

FIGURE 8. Inferior view (A) and superior view (B) of the surface models andsectioned image showing locational relationship of caudate nucleus,lentiform nucleus, thalamus, and lateral ventricle.

FIGURE 9. Surface models of right dural venous sinuses and cranium.

The Journal of Craniofacial Surgery & Volume 23, Number 4, July 2012 Surface Models of a Cadaver Head

* 2012 Mutaz B. Habal, MD 1179

Copyright © 2012 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.

assist students in the study of the topographic anatomy and sec-tional anatomy of the head, as well as neuroanatomy. In addition, itis expected that the raw data will stimulate researchers to developthree-dimensional medical simulators for improvement of clinicalpractice in neurosurgery and otorhinolaryngology.

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1180 * 2012 Mutaz B. Habal, MD

Copyright © 2012 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.