Advanced features of whole body sectioned images: Virtual Chinese Human

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  • ORIGINAL COMMUNICATION

    Advanced Features of Whole Body SectionedImages: Virtual Chinese Human

    LEI TANG,1 MIN SUK CHUNG,2 QIAN LIU,3 AND DONG SUN SHIN2*1Department of Anatomy, Southern Medical University, China

    2Department of Anatomy, Ajou University School of Medicine, Republic of Korea3Key Laboratory of Biomedical Photonics of Ministry of Education,

    Huazhong University of Science and Technology, China

    Serially sectioned images of whole cadavers have become available throughthe work of four projects: the Visible Human Project, the Visible Korean, theChinese Visible Human, and the Virtual Chinese Human (VCH). For the VCH,new techniques and equipment were developed and applied to two female andtwo male cadavers to overcome some of the limitations noted in previous stud-ies. In this article on the VCH, the procedures described are those used on amale cadaver. The cadaver was young with little to no pathology; there wereno at back artifacts because the cadaver was frozen and embedded in theupright position. Sectioned images (intervals, 0.2 mm) were of exceptionalquality and resolution (0.1 mm-sized pixels). Several specic structures wereoutlined (intervals, 0.6 mm) to acquire segmented images, from which surfacemodels were constructed. The VCH data are to be distributed worldwide andare expected to encourage other investigators to produce useful three-dimen-sional images and develop interactive simulation programs for clinical practice.Clin. Anat. 23:523529, 2010. VVC 2010 Wiley-Liss, Inc.

    Key words: Visible Human Projects; cadaver; frozen sections; cross-sectionalanatomy; computer generated three-dimensional imaging

    INTRODUCTION

    The Visible Human Project was the rst to obtainserially sectioned images of whole human cadavers(1994, male; 1995, female). The key technique usedfor obtaining these sectional images at 0.331 mmintervals was to sequentially mill the cadaver, previ-ously frozen in a gelatin solution (Spitzer et al.,1996; Spitzer and Scherzinger, 2006). This tech-nique was modied by Korean investigators to pre-pare data of the Visible Korean project in 2002 (Parket al., 2005a, 2006). Subsequently, in 2003, themethodology was applied by separate groups of Chi-nese researchers to launch the Chinese VisibleHuman project (Zhang et al., 2004a, 2006) and theVirtual Chinese Human (VCH) (Zhong et al., 2003;Yuan et al., 2003, 2008) (Table 1). For the VCH, sev-eral unique techniques with new equipment wereused to address the limitations of previous projects:the whole cadaver was frozen, embedded, and sec-tioned in the upright posture to acquire high-quality

    sectioned surfaces with the natural body contour.The techniques were applied in three young adultsand a female infant. The aim of this study wasto elaborate and distribute the VCH data of thefour cadavers. This information can be used as an al-ternative resource for scientists interested in devel-oping software for medical education and clinical

    *Correspondence to: Dong Sun Shin, Department of Anatomy,Ajou University School of Medicine, Suwon 443-821, Republic ofKorea. E-mail: sds@ajou.ac.kr

    Grant sponsor: The National High Technology Research and De-velopment Program of China (863 Program); Grant number:2006AA02Z343; Grant sponsor: Guangdong Provincial Scienceand Technology; Grant number: 2005B0301009.

    Received 8 July 2008; Revised 12 January 2010; Accepted 10February 2010

    Published online 7 April 2010 in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ca.20975

    VVC 2010 Wiley-Liss, Inc.

    Clinical Anatomy 23:523529 (2010)

  • training. This article reports on mainly the last malecadaver among the four subjects (Table 2).

    MATERIALS AND METHODS

    Body Preservation

    One male cadaver (VCH-M2) was selected fromthose donated for medical research and educationwith the consent of their relatives. The cadaver wasa 28-year-old, with a height of 166 cm and weight of56 kg. The patient was the subject of a court-or-dered lethal injection (Table 2).

    Fourteen hours after death, the rst step of han-dling the cadaver was initiated. Without exsanguina-tion, approximately 1.2 L of perfusion solution, amixture of 5% phenol, 1% benzoic acid, and vermil-ion starch, was injected through the right commoncarotid artery of the cadaver. This was followed bythe injection of red dye (4 g % iron oxide red) withan air pressure of 0.4 3 105 Pa.

    The cadaver initially had a at back and buttocksbecause of the supine position after the lethal injec-tion. Following perfusion with the above-mentionedsolution, the body was turned to face the oor andits back and buttocks were massaged for half anhour to almost full recovery of the normal body con-tour. The cadaver was stood upright with the backcontours preserved and then sealed in a plastic bagto be frozen (25 to 358C) with a saturated sodiumchloride solution for 72 hr.

    Sectioning

    After freezing, the cadaver was oriented verticallyin an upright embedding mold (580 mm 3 380 mm 32,200mm). A small amount (about 50 L) of embeddingagent (gelatin: blue dye: water 7 kg: 10 g: 450 L)was then poured into the mold to be frozen to preventrapid volume increase of the agent from compressingthe cadaver. This procedure was repeated until the

    embedding mold was lled with the frozen embeddingagent. Prior to sectioning, the embedding mold wasremoved to obtain the cadaver block (Fig. 1).

    The VCH laboratory for serial sectioning of thestanding cadaver block was designed and con-structed on the basement and ground oors of abuilding, where a tall cryomacrotome (JX1500A) wasinstalled. The cadaver block was xed to the plate ofthe cryomacrotome in the basement and it movedupward during the serial sectioning (Fig. 1b). Tokeep the cadaver block frozen, the basement itself wasdesigned as a freezer and maintained at a temperatureof 25 to 358C. On the ground oor, the cadaverblock was serially sectioned using the milling disc onthe cryomacrotome. The diameter of the milling discwas 400 mm, and its rotating speed was adjusted to850 rpm for optimal quality of the sectioned surfaces(Fig. 2a). The entire cadaver in the block was seriallysectioned at 0.2 mm intervals. Frost and debris werewiped away from each sectioned surface. To facili-tate manual cleaning of the sectioned surfaces, theground oor was designed as a refrigerator withtemperatures maintained between 0 and +58C.

    Photography

    Serial sections were digitally photographed with adigital camera (PHASE ONE H25TM) with AF 24 mm/2.8D lens (NikonTM). The resolution and color depthof the camera was 5,440 3 4,080 and 48 bits color,respectively. The digital camera captured the 544mm 3 408 mm-sized sectioned surfaces to generate0.1 mm-sized pixel images (Table 2). The photo-graphed surface included not only the cadaver andblue embedding agent, but also a ruler, color patch,gray scale, and image number counter (Fig. 2b).

    Above the cadaver block, a strobe (ElinchromStyle1200RXTM) was positioned and adjusted to pro-vide equal illumination of all areas on the sectionedsurface. The same brightness was veried by an ex-posure meter when the strobe ashed.

    TABLE 1. Summary of Virtual Human Data Sets Worldwide

    Project Yeara Laboratory Cadavers Intervals (mm) Pixel size (mm)

    Visible Human Project 1994 Denver, USA 1 male, 1 female 0.331 0.33Visible Korean 2002 Suwon, Korea 1 male 0.2 0.2Chinese Visible Human 2003 Chongqing, China 3 males, 3 females 0.11 0.2Virtual Chinese Human 2003 Guangzhou, China 2 males, 2 females 0.10.2 0.10.2

    aYear refers to when the sectioned images were made from the rst cadaver in each project.

    TABLE 2. Features of the Sectioned Images of the Virtual Chinese Human (VCH)

    Project(year) Sex (Age)

    Intervals(number)

    Resolution(pixel size)

    Bit depth(le format)

    One le size(total le size)

    VCH-F1 (2003) Female(19 years)

    0.2 mm(8,556)

    3,024 3 2,016(0.2 mm)

    24 bits color(TIFF)

    18 MB(149 GB)

    VCH-M1 (2003) Male(24 years)

    0.2 mm(9,232)

    3,024 3 2,016(0.2 mm)

    24 bits color(TIFF)

    18 MB(161 GB)

    VCH-F2 (2004) Female(10 months)

    0.1 mm(4,265)

    4,256 3 2,848(0.1 mm)

    24 bits color(RAW)

    13 MB(53 GB)

    VCH-M2 (2005) Male(28 years)

    0.2 mm(9,320)

    5,440 3 4,080(0.1 mm)

    48 bits color(RAW)

    127 MB(1,331 GB)

    524 Tang et al.

  • Photography was performed with the strobesashing automatically under the following settings:shutter speed, 1/125 sec; aperture, f13; ISO, 100;exposure mode, programmed exposure; white bal-ance, auto; pixel setting, 5,440 3 4,080; le format,RAW; focal distance, 1.2 m. Photographic imageswere transferred to the computer through IEEE-1394.On the computer screen, whether the sectioned sur-face was completely cleaned and whether the focus,brightness, and color of the sectioned image werecorrect were conrmed. After conrmation, the nextserial section was obtained (Fig. 2, Table 2).

    Full serial sectioning produced 9,320 sequentialimages with 0.2 mm intervals. The le size of eachsectioned image was 127 megabytes, and the totalle size of 9,320 acquired images was more than 1terabyte (Fig. 3a, Table 2).

    Segmentation

    On the sectioned images, medical experts labeledimportant anatomic structures of the whole body inboth English and Chinese.

    Forty-ve anatomic structures were selected foroutlining. The structures were categorized as theintegumentary, skeletal, muscular, digestive, respi-ratory, urogenital, cardiovascular, lymphoid, sen-sory, nervous, and endocrine systems. Using AdobePhotoshop version CS3, these structures wereautomatically, semi-automatically, or manuallydelineated in every three sectioned images to con-struct 3,107 segmented images (intervals, 0.6 mm)(Fig. 3b) (Park et al., 2005b).

    The segmented images of every structure werestacked in sequence and surface reconstruction was

    Fig. 1. Procedure for embedding the cadaver. a: The cadaver in the verticalposition was placed inside a mold, where the embedding agent was poured and fro-zen. b: The mold was removed to produce the cadaver block, attached on the cryo-macrotome. [Color gure can be viewed in the online issue, which is available atwww.interscience.wiley.com.]

    Fig. 2. Procedure for sectioning. a: The cadaver block on the cryomacrotomewas sectioned with a milling disc. b: Each sectioned surface was photographed tocapture the image. [Color gure can be viewed in the online issue, which is avail-able at www.interscience.wiley.com.]

    525Virtual Chinese Human

  • performed using the Visualization Toolkit libraryTM (Kit-ware). This is an open-source, freely available softwaresystem for 3D computer graphics, image processing,and visualization used to create surface models of theoutlined structures (Figs. 4 and 5) (Yuan et al., 2008).

    RESULTS

    We describe only the results from the second malecadaver (VCH-M2) who had an ordinary body size(height, 166 cm; weight, 56 kg).

    There were no denitive pathological ndings.This was likely due to the young age (28 years old)and the cause of death, which was execution bylethal injection. Postmortem degenerative changeswere minimized thanks to the rapid perfusion follow-ing death. Further, the manner in which the speci-men was prepared diminished the at appearance ofthe upper back and gluteal regions in the sectionedimages, segmented images (Fig. 3) as well as in thesurface model of the skin (Fig. 5).

    Because of the remarkable quality of the sec-tioned images, even small structures could be easily

    Fig. 3. a: Selected cross-sectional images through various regions of the body:background space surrounding the body was converted to a black color. b: Corre-sponding segmented images where specically outlined anatomical structures werelled with different colors. [Color gure can be viewed in the online issue, which isavailable at www.interscience.wiley.com.]

    526 Tang et al.

  • Fig. 5. Surface model of the skin, which showedthe natural curve of the back and buttocks similar to aliving person. [Color gure can be viewed in the onlineissue, which is available at www.interscience.wiley.com.]

    Fig. 4. Surface models of various structures includ-ing arteries.

  • identied and segmented. As a result, we preparedthe segmented images of 45 specic body structuresat 0.6 mm intervals. The red colored dye injectedinto the arteries greatly facilitated their segmenta-tion (Fig. 3). From the segmented images, usefulsurface models were constructed (Fig. 4).

    DISCUSSION

    Four individual projects have successfully pro-duced sectioned images of the whole human body:The Visible Human Project in Denver, USA; theVisible Korean in Suwon, Korea; the Chinese VisibleHuman in Chongqing, China; the VCH in Guangzhou,China (Table 1). Each project has its own advantagesas well as limitations, and each complements theother. The increased data sets of the sectionedimages are useful for the potential users selection.Better applications for medical simulation can beaccomplished by many technical and clinical groupsaround the world. Details of the results and applica-tions of the three projects have been illustrated inthe special issue of Clinical Anatomy in 2006 (Park etal., 2006; Spitzer and Scherzinger, 2006; Zhang etal., 2006). This article subsequently introduces therest of the project, the VCH.

    The distinguishing elements of the VCH work arethe use of younger adults with little or no pathology,the incorporation of a massage step during specimenpreparation to minimize artefactual attening of theupper back and gluteal region, a trial of the newupright postures during body processing and its sec-tioning, and improvements in image capture of thesectioned surfaces and intervals of segmentation.

    The adult cadavers in the VCH were 19, 24, and28 years of age and generally younger than the indi-viduals used in other projects. In the Visible HumanProject, the male and female cadavers were 38 and59 years of age, respectively (Spitzer et al., 1996).In addition, a 10-month-old female cadaver wasserially sectioned (VCH-F2), and the data set fromthis baby could be used for the construction of pedi-atric simulation (Table 2).

    The VCH bodies were relatively normal with lim-ited pathology. While no cadaver is likely totally freeof pathological ndings and anatomical variations,attempts to nd and use healthy individual is valua-ble. The Visible Korean cadaver died of leukemia andshowed severe pneumonia (Park et al., 2005a).However, in this study, the male cadaver (VCH-M2)was executed by lethal injection, similar to the malecadaver used for the Visible Human Project (Spitzeret al., 1996). The previous cadavers (VCH-F1 andVCH-M1) died of food poisoning (Yuan et al., 2003;Zhong et al., 2003), whereas the cause of death ofthe female child (VCH-F2) was fetal distress. Normalanatomical models are of great use as referenceimages for further research.

    The sectioned images of the VCH showed luster oftissue (Fig. 3a), which was achieved by injection ofthe xative (a mixture of phenol, benzoic acid, andvermilion starch) into the cadavers arteries. Thepositive effect of the xation was consistent with thefact that embalmed cadavers might show more de-

    nite tissue characteristics than the frozen cadavers.The xative also assisted in the subseq...

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