Name: Técnicas de Renderização de Imagens em Tomografia Computadorizada Pós-Morte: Avaliação da Saúde Biológica e Perfil em Cetáceos Encalhados (Vídeo) | JoVE Journal
Uploaded: 2020-09-27T15:00:00.000+00:00
Duration: 12 min 32 s
Description: Aprenda técnicas de renderização de imagens em tomografia computadorizada pós-morte para avaliar a saúde biológica de cetáceos encalhados. Este método auxilia radiologistas e veterinários na interpretação de achados postmortem.

ai_agent_IP

ai_agent

maintenance

instantTrialDurationMinutes

isBiopharma

enableNewMyJoveSectionDesign

educationFeatures

seoMetaApi

ai_copilot_institution_blacklist

ai_chat_institution_blacklist

freeAccessWindow

ssoRoleCapture

scheduledMaintenanceBanner

joveLabsFeatures

disable_autoplay_for_bots

extended_trial_duration

5 minutes

playerTrialDesktop

The authors would like to thank the Agriculture, Fisheries and Conservation Department of the Hong Kong Special Administrative Region Government for the continuous support in this project. Sincere appreciation is also extended to veterinarians, staff, and volunteers from the Aquatic Animal Virtopsy Lab, City University of Hong Kong, Ocean Park Conservation Foundation Hong Kong and Ocean Park Hong Kong&#160;for paying great effort on the stranding response in this project. Special gratitude is owed to technicians in CityU Veterinary Medical Centre and Hong Kong Veterinary Imaging Centre for operating the CT and MRI units for the present study. Any opinions, findings, conclusions or recommendations expressed herein do not necessarily reflect the views of the Marine Ecology Enhancement Fund or the Trustee. This project was funded by the Hong Kong Research Grants Council (Grant number: UGC/FDS17/M07/14), and the Marine Ecology Enhancement Fund (grant number: MEEF2017014, MEEF2017014A,&#160;MEEF2019010 and MEEF2019010A), Marine Ecology Enhancement Fund, Marine Ecology &#38; Fisheries Enhancement Funds Trustee Limited. Special thanks to Dr. Mar&#237;a Jos&#233; Robles Malagamba for English editing of this manuscript.

NOTE: In the framework of the Hong Kong cetacean virtopsy stranding response program, stranded cetaceans were routinely examined by PMCT. The authors were in charge of virtopsy scanning, data postprocessing (e.g., image reconstruction and rendering), data interpretation, and virtopsy reporting1. This advanced technology emphasizes attentive findings and gives insights on the initial investigation of PM findings prior to conventional necropsy (https://www.facebook.com/aquanimallab).
1. Data preparation
<ol>
	<li>Export the acquired CT datasets in DICOM 3.0 format. Copy the DICOM folder to computer (e.g., desktop).</li>
	<li>Open a free or commercial DICOM viewer. The following steps are based on the TeraRecon Aquarius iNtuition Workstation (version 4.4.12).</li>
	<li>Double-click the icon of Aquarius iNtuition Client Viewer (AQi) icon. Enter user name, password, and server name in the appropriate fields. Click the Login button. 
	NOTE: Make sure that the server name field has the correct server IP address.</li>
	<li>Click Import under the data management tool buttons and select the DICOM folder to import. Click the Update icon to renew the study list after the import status reaches 100%.</li>
	<li>View the datasets by selecting 1 or multiple CT series from the Patient List by double-left-clicking the series.</li>
	<li>After loading the designated series, click the Window Layout Button for the 2x2 display interface, showing a 2x2 default layout, a 3D volume rendered image (upper-right panel) and 3 MPR images in axial view (upper-left panel), coronal view (lower-left panel), sagittal view (lower-right panel), giving different orientations.</li>
	<li>Evaluate the virtopsy datasets thoroughly using different image rendering techniques provided.</li>
</ol>
2. Multiplanar reconstruction (MPR)
<ol>
	<li>Display the default MPR from axial view (upper-left panel), coronal view (lower-left panel), and sagittal view (lower-right panel) after loading the series. Change the rendering mode to MPR by either right-clicking the image and select MPR or click MPR in the Rendering Mode Mini-Toolbar.</li>
	<li>Evaluate the virtopsy datasets from the first image to the last image using the axial view, followed by coronal and sagittal views, with the assistance of the following functions: Click Slice, left-click-hold mouse button and drag the mouse to view and adjust the CT image slice by slice.</li>
	<li>Click Pan, left-click-hold mouse button and drag the mouse to adjust the location of the image inside the panel.</li>
	<li>Click Zoom, left-click-hold mouse button and drag the mouse to magnify or minify the image.</li>
	<li>Select the appropriate pre-set window/levels by clicking Abd 1 (window width: 350, window level: 75), Abd 2 (window width: 250, window level: 40), Head (window width: 100, window level: 45), Lung (window width: 1500, window level: -700), Bone (window width: 2200, window level: 200) in the Window/Level Mini-Toolbar, depending on the regions of interest.</li>
	<li>Click Window/Level (W/L), left-click-hold mouse button and drag the mouse to manually adjust the window width and window level of the CT slice.</li>
	<li>Click Rotate, left-click-hold mouse button and drag the mouse to rotate the MPR images.</li>
	<li>Left-click-hold mouse button on the center of MPR Crosshairs to concurrently adjust the regions of interest and slices in 3 MPR images. 
	NOTE: There are mouse modes for the 4 main functions of rotations, panning, zooming and window/level changes provided by AQi to facilitate the viewing process. For keyboard shortcuts, see Table 1.</li>
</ol>
3. Curved planar reformation (CPR)
<ol>
	<li>Decide the region of anatomical interest. Left-click-hold mouse button on the center of MPR crosshairs to the particular region of interest.</li>
	<li>View the MPR from 3 different views. Ensure the MPR crosshairs is placed in a correct location. Adjust the MPR crosshairs if it is not.</li>
	<li>Select 1 display panel from axial, coronal, and sagittal views as study panel, e.g., aiming to view the flipper from an axial view.</li>
	<li>Depending on the study panel, adjust the extended line of MPR crosshairs (e.g., blue color) from coronal view perpendicularly to the region of interest by left-click-hold mouse button on the rotation point of extended line.</li>
	<li>Adjust another extended line (e.g., red color) of MPR crosshairs from sagittal view parallel to the region of interest by left-click-hold mouse button on the rotation point of extended line.</li>
	<li>Look at the axial view to check whether the region of interest is adjusted correctly. Adjust the extended lines if it is not. Evaluate the virtopsy datasets using the 4 main functions of rotation, panning, zooming and window/level changes. 
	NOTE: There are 3 colored extended lines of MPR crosshairs (green, red, and blue), representing different alignments of the MPR plane (Figure 2).</li>
</ol>
4. Maximum intensity projection (MIP)
<ol>
	<li>Change the rendering mode to MIP by either right-clicking the image and selecting MIP or by clicking MIP in the Rendering Mode Mini-Toolbar.</li>
	<li>Adjust the slab thickness on the right upper corner (minimum: 1 mm, maximum: 500 mm) by clicking the green annotation and select a new thickness to visualize the regions of interest, e.g., the bronchial tree in the lung.</li>
	<li>Evaluate the virtopsy datasets using the 4 main functions of rotation, panning, zooming, and window/level changes.</li>
</ol>
5. Minimum intensity projection (MinIP)
<ol>
	<li>Change the rendering mode to MIP by either right-clicking the image and selecting MinIP or by clicking MinIP in the Rendering Mode Mini-Toolbar.</li>
	<li>Adjust the slab thickness on the right upper corner (minimum: 1 mm, maximum: 500 mm) by clicking the green annotation and select a new thickness to visualize the regions of interest (e.g., the bronchial tree in the lung).</li>
	<li>Evaluate the virtopsy datasets using the 4 main functions of rotation, panning, zooming, and window/level changes.</li>
</ol>
6. Direct volume rendering (DVR)
NOTE: As 1 of the default display 2x2 interfaces, DVR (upper-right panel) shows the 3D rendered images of the carcass. The default DVR template setting is AAA (abdominal aortic aneurysm; window width: 530, window level: 385), giving a gross skeletal structure of the carcass.
<ol>
	<li>Automatically adjust the windowing setting by clicking Template under the Viewer and select the appropriate DVR template, e.g., Gray 10% (window width: 442, window level: 115), Fracture (window width: 2228, window level: 1414) if needed.</li>
	<li>Click Window/Level (W/L), left-click-hold mouse button and drag the mouse to adjust the window width and window level of the CT slice manually, giving an outer layer (e.g., epidermal surface) to inner layer (e.g., internal structure).</li>
	<li>Use the 4 main functions of rotation, panning, zooming, and window/level changes for further corrections. 
	NOTE: All DVR templates provided by AQi are human clinical oriented, not designated for PM imaging of cetaceans.</li>
</ol>
7. Segmentation and Region-of-Interest (ROI) Editing
<ol>
	<li>Segment the CT image slice using 3 different tools, Slab and Cube View tool, Free ROI tool, and Dynamic region growing tool.</li>
	<li>For Slab and Cube View tool, click Slab under Tool, giving a parallel display line. Adjust the slab location by relocating the MPR crosshairs from the corresponding MPR views. Change the slab thickness (minimum: 1 mm, maximum: 500 mm) via the slab thickness bar, resulting a segmentation of 3D rendered images of the carcass.</li>
	<li>For Free ROI tool, click FreeRO under Tool. Hold on the Shift key on the keyboard, and use either Draw Free Curve on MPR, Draw Circle on MPR, or Draw Sphere on MPR to exclude/include the region of interest from the MPR views and DVR.</li>
	<li>For Dynamic region growing tool, click Region under Tool. Hold on the Shift key on keyboard, left-click-hold mouse button and scroll the middle button of the mouse (scroll-up: increase the selecting region, scroll-down: decrease the selecting region), giving a highlighted region. Click Exclude to delete the region. Click Include to keep the region.</li>
</ol>
8. Transfer Functions (TF)
<ol>
	<li>Click 3D Setting under Viewer, select Copy to create a new 3D reconstructed model.</li>
	<li>In the new 3D reconstructed model, click FreeRO or Region under Tool. Hold on the Shift key on the keyboard, use 3D VR to include the region of interest and then click Select.</li>
	<li>Configure the 3D settings, including W/L Slider, W/L Text-input Boxes, VR Pull-down Menu, Opacity Slider (minimum: 0, maximum: 1), Opacity Text-input Box, and HU Range Color Slider under 3D Setting.</li>
	<li>Right-click 1 of the sliders in the color slider bar to change the color of the DVR. Select Change Color and define a custom color from the color palette if needed.</li>
</ol>
9. Perspective Volume Rendering (PVR)
<ol>
	<li>To launch the Flythrough Module, right-click on the selected series and select Flythrough from the right-click menu.</li>
	<li>Choose the Primary 3D of Reading Style Preference Wizard for primary view selection. Click the 2x2 screen layout and OK, resulting in an automatically RVR, e.g., colon. Make sure the region of interest is selected.</li>
	<li>Build a flight path by placing the start and end of control points by drawing a path. Correct the path by clicking the Edit Connection/Edit Path radio button in the tool panel if there is a broken path or missing structure, editing the control points for smoother sections of the curve or correcting problems. Create new control points by clicking on the flight path. Once the flight path is correct, click OK.</li>
	<li>View the Flythrough window displayed, showing a Main flythrough window, MPR views and Flat view.</li>
	<li>Use Cine Tools by clicking the Tool Panel located on the right side of the screen to evaluate the luminal structure. Adjust the speed and direction of the flythrough using Fly backward, Pause, Fly Forward, Slow down flythrough, and Speed up flythrough under the Cine tools.</li>
</ol>
10. Data evaluation
<ol>
	<li>Conduct virtopsy evaluation systematically from head to tail. It is generally within 30 minutes, acting as a reference to guide veterinarians for subsequent necropsy.</li>
	<li>After necropsy, compare virtopsy findings and necropsy findings. Based on the site report, virtopsy, necropsy, and sample analysis (e.g., histopathology and microbiology), conclude the PM investigation on the biological health and profile of the stranded cetacean.</li>
</ol>

<ol><li>Tsui, H. C. L., Kot, B. C. W., Chung, T. Y. T., Chan, D. K. P. <a target="_blank" href="https://www.frontiersin.org/articles/10.3389/fmars.2020.542015/abstract">Virtopsy as a revolutionary tool for cetacean stranding programs: Implementation and management.</a> Frontiers in Marine Sciences. , (2020).</li>
<li>Jacobsen, C., Bech, B. H., Lynnerup, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+comparative+study+of+cranial%2C+blunt+trauma+fractures+as+seen+at+medicolegal+autopsy+and+by+computed+tomography%5BTitle%5D)+AND+%22BMC+Medical+Imaging%22%5BJournal%5D)">A comparative study of cranial, blunt trauma fractures as seen at medicolegal autopsy and by computed tomography.</a> BMC Medical Imaging. 9 (18), 1-9 (2009).</li>
<li>Jacobsen, C., Lynnerup, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Craniocerebral+trauma--congruence+between+post-mortem+computed+tomography+diagnoses+and+autopsy+results%3A+a+2-year+retrospective+study%5BTitle%5D)+AND+%22Forensic+Science+International%22%5BJournal%5D)">Craniocerebral trauma--congruence between post-mortem computed tomography diagnoses and autopsy results: a 2-year retrospective study.</a> Forensic Science International. 194 (1-3), 9-14 (2010).</li>
<li>Plattner, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Virtopsy-postmortem+multislice+computed+tomography+%28MSCT%29+and+magnetic+resonance+imaging+%28MRI%29+in+a+fatal+scuba+diving+incident%5BTitle%5D)+AND+%22Journal+of+Forensic+Sciences%22%5BJournal%5D)">Virtopsy-postmortem multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) in a fatal scuba diving incident.</a> Journal of Forensic Sciences. 48 (6), 1347-1355 (2003).</li>
<li>Jackowski, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Visualization+and+quantification+of+air+embolism+structure+by+processing+postmortem+MSCT+data%5BTitle%5D)+AND+%22Journal+of+Forensic+Sciences%22%5BJournal%5D)">Visualization and quantification of air embolism structure by processing postmortem MSCT data.</a> Journal of Forensic Sciences. 49 (6), 1339-1342 (2004).</li>
<li>Aghayev, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Pneumomediastinum+and+soft+tissue+emphysema+of+the+neck+in+postmortem+CT+and+MRI%3B+a+new+vital+sign+in+hanging%5BTitle%5D)+AND+%22Forensic+Science+International%22%5BJournal%5D)">Pneumomediastinum and soft tissue emphysema of the neck in postmortem CT and MRI; a new vital sign in hanging.</a> Forensic Science International. 153 (2-3), 181-188 (2005).</li>
<li>Jackowski, C., Persson, A., Thali, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Whole+Body+Postmortem+Angiography+with+a+High+Viscosity+Contrast+Agent+Solution+Using+Poly+Ethylene+Glycol+as+Contrast+Agent+Dissolver%5BTitle%5D)+AND+%22Journal+of+Forensic+Sciences%22%5BJournal%5D)">Whole Body Postmortem Angiography with a High Viscosity Contrast Agent Solution Using Poly Ethylene Glycol as Contrast Agent Dissolver.</a> Journal of Forensic Sciences. 53 (2), 465-468 (2008).</li>
<li>Jackowski, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Virtopsy%3A+postmortem+minimally+invasive+angiography+using+cross+section+techniques+-+implementation+and+preliminary+results%5BTitle%5D)+AND+%22Journal+of+Forensic+Sciences%22%5BJournal%5D)">Virtopsy: postmortem minimally invasive angiography using cross section techniques - implementation and preliminary results.</a> Journal of Forensic Sciences. 50 (5), 1175-1186 (2005).</li>
<li>Grabherr, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Postmortem+CT+angiography+compared+with+autopsy%3A+a+forensic+multicenter+study%5BTitle%5D)+AND+%22Radiology%22%5BJournal%5D)">Postmortem CT angiography compared with autopsy: a forensic multicenter study.</a> Radiology. 288 (1), 270-276 (2018).</li>
<li>Yuen, A. H. L., Tsui, H. C. L., Kot, B. C. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Accuracy+and+reliability+of+cetacean+cranial+measurements+using+computed+tomography+three+dimensional+volume+rendered+images%5BTitle%5D)+AND+%22PloS+one%22%5BJournal%5D)">Accuracy and reliability of cetacean cranial measurements using computed tomography three dimensional volume rendered images.</a> PloS one. 12 (3), 0174215(2017).</li>
<li>Kot, B. C. W., Chan, D. K. P., Yuen, A. H. L., Tsui, H. C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Diagnosis+of+atlanto-occipital+dissociation%3A+Standardised+measurements+of+normal+craniocervical+relationship+in+finless+porpoises+%28genus+Neophocaena%29+using+postmortem+computed+tomography%5BTitle%5D)+AND+%22Scientific+Reports%22%5BJournal%5D)">Diagnosis of atlanto-occipital dissociation: Standardised measurements of normal craniocervical relationship in finless porpoises (genus Neophocaena) using postmortem computed tomography.</a> Scientific Reports. 8, 8474(2018).</li>
<li>Chan, D. K. P., Tsui, H. C. L., Kot, B. C. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Database+documentation+of+marine+mammal+stranding+and+mortality%3A+current+status+review+and+future+prospects%5BTitle%5D)+AND+%22Diseases+of+Aquatic+Organisms%22%5BJournal%5D)">Database documentation of marine mammal stranding and mortality: current status review and future prospects.</a> Diseases of Aquatic Organisms. 126 (3), 247-256 (2017).</li>
<li>Chan, D. K. P., Kot, B. C. W. <a target="_blank" href="https://www.vin.com/apputil/content/defaultadv1.aspx?pId=18363&meta=Generic&catId=98268&id=7977743&ind=135&objTypeID=17">Cetaceans postmortem multimedia analysis platform (CPMAP): pilot web-accessed database of a virtopsy-driven stranding response program in the Hong Kong waters.</a> Proceedings of International Association for Aquatic Animal Medicine 48th Annual Conference, Cancun, MEX. , (2017).</li>
<li>Hamel, P. E. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Postmortem+computed+tomography+and+magnetic+resonance+imaging+findings+in+a+case+of+coinfection+of+dolphin+morbillivirus+and+Aspergillus+fumigatus+in+a+juvenile+bottlenose+dolphin+%28Tursiops+truncatus%29%5BTitle%5D)+AND+%22Journal+of+Zoo+and+Wildlife+Medicine%22%5BJournal%5D)">Postmortem computed tomography and magnetic resonance imaging findings in a case of coinfection of dolphin morbillivirus and Aspergillus fumigatus in a juvenile bottlenose dolphin (Tursiops truncatus).</a> Journal of Zoo and Wildlife Medicine. 51 (2), 448-454 (2020).</li>
<li>Weisbrod, T. C., Walsh, M. T., Marquardt, S., Giglio, R. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Computed+tomography+diagnosis+of+pneumothorax+and+cardiac+foreign+body+secondary+to+stingray+injury+in+a+bottlenose+dolphin+%28Tursiops+truncatus%29%5BTitle%5D)+AND+%22Aquatic+Mammals%22%5BJournal%5D)">Computed tomography diagnosis of pneumothorax and cardiac foreign body secondary to stingray injury in a bottlenose dolphin (Tursiops truncatus).</a> Aquatic Mammals. 46 (3), 326-330 (2020).</li>
<li>Kot, B. C. W., Tsui, H. C. L., Chung, T. Y. T., Lau, A. P. Y. <a target="_blank" href="https://www.frontiersin.org/articles/10.3389/fmars.2020.544037/abstract">Postmortem neuroimaging of cetacean brains using computed tomography and magnetic resonance imaging.</a> Frontiers in Marine Science. , (2020).</li>
<li>Lundström, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((State-of-the-art+of+visualization+in+post-mortem+imaging%5BTitle%5D)+AND+%22Acta+Pathologica%2C+Microbiologica%2C+et+Immunologica+Scandinavica%22%5BJournal%5D)">State-of-the-art of visualization in post-mortem imaging.</a> Acta Pathologica, Microbiologica, et Immunologica Scandinavica. 120 (4), 316-326 (2012).</li>
<li>Lipson, S. A. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aLipson%2C+SA+%22MDCT+and+3D+Workstations%22">MDCT and 3D Workstations</a>. , Springer. (2006).</li>
<li>Perandini, S., Faccioli, N., Zaccarella, A., Re, T. J., Mucelli, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+diagnostic+contribution+of+CT+volumetric+rendering+techniques+in+routine+practice%5BTitle%5D)+AND+%22Indian+Journal+of+Radiology+and+Imaging%22%5BJournal%5D)">The diagnostic contribution of CT volumetric rendering techniques in routine practice.</a> Indian Journal of Radiology and Imaging. 20 (2), 92-97 (2010).</li>
<li>Pavone, P., Luccichenti, G., Cademartiri, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((From+maximum+intensity+projection+to+volume+rendering%5BTitle%5D)+AND+%22Seminars+in+Ultrasound%2C+CT+and+MRI%22%5BJournal%5D)">From maximum intensity projection to volume rendering.</a> Seminars in Ultrasound, CT and MRI. 22 (5), 413-419 (2001).</li>
<li>Fishman, E. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Volume+rendering+versus+maximum+intensity+projection+in+CT+angiography%3A+what+works+best%2C+when%2C+and+why%5BTitle%5D)+AND+%22RadioGraphics%22%5BJournal%5D)">Volume rendering versus maximum intensity projection in CT angiography: what works best, when, and why.</a> RadioGraphics. 26 (3), 905-922 (2006).</li>
<li>Udupa, J. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Three-dimensional+visualization+and+analysis+methodologies%3A+a+current+perspective%5BTitle%5D)+AND+%22RadioGraphics%22%5BJournal%5D)">Three-dimensional visualization and analysis methodologies: a current perspective.</a> RadioGraphics. 19 (3), 783-806 (1999).</li>
<li>Thali, M. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((a+new+imaging+horizon+in+forensic+pathology%3A+virtual+autopsy+by+postmortem+multislice+computed+tomography+%28MSCT%29+and+magnetic+resonance+imaging+%28MRI%29+-+a+feasibility+study%5BTitle%5D)+AND+%22Journal+of+Forensic+Sciences%22%5BJournal%5D)">a new imaging horizon in forensic pathology: virtual autopsy by postmortem multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) - a feasibility study.</a> Journal of Forensic Sciences. 48 (2), 386-403 (2003).</li>
<li>Dalrymple, N. C., Prasad, S. R., Freckleton, M. W., Chintapalli, K. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Informatics+in+radiology+%28infoRAD%29%3A+introduction+to+the+language+of+three-dimensional+imaging+with+multidetector+CT%5BTitle%5D)+AND+%22RadioGraphics%22%5BJournal%5D)">Informatics in radiology (infoRAD): introduction to the language of three-dimensional imaging with multidetector CT.</a> RadioGraphics. 25 (5), 1409-1428 (2005).</li>
<li>Thali, M. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Virtopsy+-+documentation%2C+reconstruction+and+animation+in+forensic%3A+individual+and+real+3D+data+based+geo-metric+approach+including+optical+body%2Fobject+surface+and+radiological+CT%2FMRI+scanning%5BTitle%5D)+AND+%22Journal+of+Forensic+Sciences%22%5BJournal%5D)">Virtopsy - documentation, reconstruction and animation in forensic: individual and real 3D data based geo-metric approach including optical body/object surface and radiological CT/MRI scanning.</a> Journal of Forensic Sciences. 50 (2), 428-442 (2015).</li>
<li>Tsui, H. C. L., Kot, B. C. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Role+of+image+reformation+techniques+in+postmortem+computed+tomography+imaging+of+stranded+cetaceans%5BTitle%5D)+AND+%22Proceedings+of+International+Association+for+Aquatic+Animal+Medicine+47th+Annual+Conference%22%5BJournal%5D)">Role of image reformation techniques in postmortem computed tomography imaging of stranded cetaceans.</a> Proceedings of International Association for Aquatic Animal Medicine 47th Annual Conference. , Virginia Beach, VA, USA. (2016).</li>
<li>Ampanozi, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Format+preferences+of+district+attorneys+for+post-mortem+medical+imaging+reports%3A+understandability%2C+cost+effectiveness%2C+and+suitability+for+the+courtroom%3A+a+questionnaire+based+study%5BTitle%5D)+AND+%22Legal+Medicine+%28Tokyo%29%22%5BJournal%5D)">Format preferences of district attorneys for post-mortem medical imaging reports: understandability, cost effectiveness, and suitability for the courtroom: a questionnaire based study.</a> Legal Medicine (Tokyo). 14 (3), 116(2012).</li>
<li>Ebert, L. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Forensic+3D+visualization+of+CT+data+using+cinematic+volume+rendering%3A+a+preliminary+study%5BTitle%5D)+AND+%22American+Journal+of+Roentgenology%22%5BJournal%5D)">Forensic 3D visualization of CT data using cinematic volume rendering: a preliminary study.</a> American Journal of Roentgenology. 208 (2), 233-240 (2017).</li>
<li>Alonso-Farré, J. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Cross-sectional+anatomy%2C+computed+tomography+and+magnetic+resonance+imaging+of+the+head+of+common+dolphin+%28Delphinus+delphis%29+and+striped+dolphin+%28Stenella+Coeruleoalba%29%5BTitle%5D)+AND+%22Anatomia%2C+Histologia%2C+Embryologia%22%5BJournal%5D)">Cross-sectional anatomy, computed tomography and magnetic resonance imaging of the head of common dolphin (Delphinus delphis) and striped dolphin (Stenella Coeruleoalba).</a> Anatomia, Histologia, Embryologia. 44 (1), 13-21 (2015).</li>
<li>Gascho, D., Thali, M. J., Niemann, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Post-mortem+computed+tomography%3A+technical+principles+and+recommended+parameter+settings+for+high-resolution+imaging%5BTitle%5D)+AND+%22Medicine%2C+Science+and+the+Law%22%5BJournal%5D)">Post-mortem computed tomography: technical principles and recommended parameter settings for high-resolution imaging.</a> Medicine, Science and the Law. 58 (1), 70-83 (2018).</li>
<li>Lee, E. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((MDCT+evaluation+of+thoracic+aortic+anomalies+in+pediatric+patients+and+young+adults%3A+comparison+of+axial%2C+multiplanar%2C+and+3D+images%5BTitle%5D)+AND+%22American+Journal+of+Roentgenology%22%5BJournal%5D)">MDCT evaluation of thoracic aortic anomalies in pediatric patients and young adults: comparison of axial, multiplanar, and 3D images.</a> American Journal of Roentgenology. 182 (3), 777-784 (2004).</li>
<li>Errickson, D., Thompson, T. J. U., Rankin, B. W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+application+of+3D+visualization+of+osteological+trauma+for+the+courtroom%3A+a+critical+review%5BTitle%5D)+AND+%22Journal+of+Forensic+Radiology+and+Imaging%22%5BJournal%5D)">The application of 3D visualization of osteological trauma for the courtroom: a critical review.</a> Journal of Forensic Radiology and Imaging. 2 (3), 132-137 (2014).</li>
<li>Prokop, M., Galanski, M. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aProkop%2C+M+%22Spiral+and+multislice+computed+tomography+of+the+body%22">Spiral and multislice computed tomography of the body</a>. , Thieme Medical Publishers. (2003).</li>
<li>Kawel, N., Seifert, B., Luetolf, M., Boehm, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Effect+of+slab+thickness+on+the+CT+detection+of+pulmonary+nodules%3A+use+of+sliding+thin-slab+maximum+intensity+projection+and+volume+rendering%5BTitle%5D)+AND+%22American+Journal+of+Roentgenology%22%5BJournal%5D)">Effect of slab thickness on the CT detection of pulmonary nodules: use of sliding thin-slab maximum intensity projection and volume rendering.</a> American Journal of Roentgenology. 192 (5), 1324-1329 (2009).</li>
<li>Vlassenbroek, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+use+of+isotropic+imaging+and+computed+tomography+reconstructions%5BTitle%5D)+AND+%22Comparative+Interpretation+of+CT+and+Standard+Radiography+of+the+Chest%2C+Medical+Radiology%22%5BJournal%5D)">The use of isotropic imaging and computed tomography reconstructions.</a> Comparative Interpretation of CT and Standard Radiography of the Chest, Medical Radiology. , Springer-Verlag. Berlin Heidelberg. 53-73 (2011).</li>
<li>van Ooijen, P. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Noninvasive+coronary+imaging+using+electron+beam+CT%3A+surface+rendering+versus+volume+rendering%5BTitle%5D)+AND+%22American+Journal+of+Roentgenology%22%5BJournal%5D)">Noninvasive coronary imaging using electron beam CT: surface rendering versus volume rendering.</a> American Journal of Roentgenology. 180 (1), 223-226 (2003).</li>
<li>Remy-Jardin, M., Remy, J., Artaud, D., Fribourg, M., Duhamel, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Volume+rendering+of+the+tracheobronchial+tree%3A+clinical+evaluation+of+bronchographic+images%5BTitle%5D)+AND+%22Radiology%22%5BJournal%5D)">Volume rendering of the tracheobronchial tree: clinical evaluation of bronchographic images.</a> Radiology. 208 (3), 761-770 (1998).</li>
<li>Bassett, J. T., Liotta, R. A., Barlow, D., Lee, D., Jensen, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Colonic+perforation+during+screening+CT+colonography+using+automated+CO2+insufflation+in+an+asymptomatic+adult%5BTitle%5D)+AND+%22Abdominal+Imaging%22%5BJournal%5D)">Colonic perforation during screening CT colonography using automated CO2 insufflation in an asymptomatic adult.</a> Abdominal Imaging. 33 (5), 598-600 (2008).</li>
</ol>

The authors have nothing to disclose.

For the clear visualization of virtopsy datasets, 8 image rendering techniques, consisting of both 2D and 3D rendering, were routinely applied to each stranded carcass for the PM investigation of their biological health and profile. These rendering techniques included MPR, CPR, MIP, MinIP, DVR, segmentation, TF, and PVR. Diverse rendering techniques are complementarily used together with windowing adjustment. The concepts of each image reformation technique and advantages are also described.
<...

Virtopsy, also known as postmortem (PM) imaging, is the examination of a carcass with advanced cross-sectional imaging modalities, including postmortem computed tomography (PMCT), postmortem magnetic resonance imaging (PMMRI), and ultrasonography1. In humans, PMCT is useful in investigating traumatic cases of skeletal alterations2,3, foreign bodies, gaseous findings4,5,6, and pathologies of the vascular system7,8,9. Since 2014, virtopsy has been routinely implemented in the Hong Kong cetacean stranding response program1. PMCT and PMMRI are able to depict patho-morphological findings on carcasses that are too decomposed to be evaluated by conventional necropsy. The non-invasive radiological assessment is objective and digitally storable, allowing second opinion or retrospective studies years later1,10,11. Virtopsy has become a valuable alternative technique to provide new insights of PM findings in stranded marine animals12,13,14,15,16. Combined with necropsy, which is the gold standard to explain the pathophysiological reconstruction and cause of death17, the biological health and profile of the animals can be addressed. Virtopsy has been gradually recognized and implemented into stranding response programs worldwide, including but not limited to Costa Rica, Japan, Mainland China, New Zealand, Taiwan, Thailand and USA1.
Image rendering techniques in radiology use computer algorithms to transform numbers into information about the tissue. For example, radiological density is expressed in conventional X-rays and CT. The vast quantity of volumetric data is stored in the Digital Imaging and Communications in Medicine (DICOM) format. CT images can be used to produce isotropic voxel data using two-dimensional (2D) and three-dimensional (3D) image rendering in a postprocessing 3D workstation for high resolution visualization18,19. Quantitative data and results are mapped to transform serially acquired axial images into 3D images with gray-scale or color parameters19,20,21. Choosing an appropriate data visualization method from diverse rendering techniques is an essential technical determinant of the visualization quality, which significantly affects the analysis and interpretation of radiological findings21. This is particularly critical for stranding work that involves personnel without any radiology background, who need to understand the results in different circumstances17. The goal of implementing these image rendering techniques is to enhance the quality on the visualization of anatomical details, relationships and clinical findings, which boosts the diagnostic value of imaging and allows an effective rendition of the defined regions of interest17,19,22,23,24,25.
Although the primary axial CT/MRI images contain most information, they may limit accurate diagnosis or documentation of pathologies as structures cannot be viewed in various orthogonal planes. Image reformation at other anatomically aligned planes permits visualization of structural relationships from another perspective without having to reposition the body26. As medical anatomy and forensic pathology data are predominantly 3D in nature, color-coded PMCT images and 3D reconstructed images are preferred to gray-scale images and 2D slice images in view of improved understandability and suitability for courtroom adjudications27,28. With the advances in PMCT technology, a concern of visualization exploration (i.e., the creation and interpretation of 2D and 3D image) in cetacean PM investigation has been raised12,29. Various volumetric rendering techniques in the radiology workstation allow radiologists, technicians, referring clinicians (e.g., veterinarians and marine mammal scientists), and even laymen (e.g., stranding response personnel, government officers and general public) to visualize and study the regions of interest. Yet, the choice of a suitable technique and confusion of terminology remain a major issue. It is necessary to understand the basic concept, strengths and limitations of the common techniques, since it would significantly influence the diagnostic value and interpretation of radiological findings. Misuse of techniques may generate misleading images (e.g., images that have distortions, rendering errors, reconstruction noises or artefacts) and lead to an incorrect diagnosis30.
The present study aims to assess 8 essential image rendering techniques in PMCT that were used to identify most of the PM findings in stranded cetaceans in Hong Kong waters. Descriptions and practical examples of each technique are provided to guide radiologists, clinicians, and veterinarians worldwide through the often difficult and complicated realm of PMCT image rendering and review for the evaluation of biological health and profile.

<table><tbody><tr><td>Aquarius iNtuition workstation</td><td>TeraRecon Inc</td><td>NA</td><td></td></tr><tr><td>Siemens 64-row multi-slice spiral CT scanner Somatom go.Up</td><td>Siemens Healthineers</td><td>NA</td><td></td></tr></tbody></table>

image rendering techniques in postmortem computed tomography: evaluation of biological health and profile in stranded cetaceans

Image Rendering Techniques in Postmortem Computed Tomography: Evaluation of Biological Health and Profile in Stranded Cetaceans

With 6 years of experience in implementing virtopsy routinely into the Hong Kong cetacean stranding response program, standardized virtopsy procedures, postmortem computed tomography (PMCT) acquisition, postprocessing, and evaluation were successfully established. In this pioneer cetacean virtopsy stranding response program, PMCT was performed on 193 stranded cetaceans, providing postmortem findings to aid necropsy and shed light on the biological health and profile of the animals. This study aimed to assess 8 image rendering techniques in PMCT, including multiplanar reconstruction, curved planar reformation, maximum intensity projection, minimum intensity projection, direct volume rendering, segmentation, transfer function, and perspective volume rendering. Illustrated with practical examples, these techniques were able to identify most of the PM findings in stranded cetaceans and served as a tool to investigate their biological health and profile. This study could guide radiologists, clinicians and veterinarians through the often difficult and complicated realm of PMCT image rendering and reviewing.

From January 2014 to May 2020, a total of 193 cetaceans that stranded in Hong Kong waters were examined by PMCT, including 42 Indo-Pacific humpback dolphins (Sousa chinensis), 130 Indo-Pacific finless porpoises (Neophocaena phocaenoides) and 21 other species. A whole-body scan was performed on 136 carcasses while 57 were partial scans on skulls and flippers. Anatomical features and pathologies commonly observed were illustrated with the 8 image rendering techniques for the evaluation of the stranded cet...

The Hong Kong cetacean stranding response program has incorporated postmortem computed tomography, which provides valuable information on the biological health and profile of the deceased animals. This study describes 8 image rendering techniques that are essential for the identification and visualization of postmortem findings in stranded cetaceans, which will help clinicians, veterinarians and stranding response personnel worldwide to fully utilize the radiological modality.

With 6 years of experience in implementing virtopsy routinely into the Hong Kong cetacean stranding response program, standardized virtopsy procedures, ...

This study aims to assess different image rendering techniques in the postmortem computed tomography for the evaluation of biological health and profile in stranded cetaceans in Hong Kong waters. This helps guide radiologists, clinicians, and veterinarians through the often difficult and complicated realm of the postmortem computed tomography image rhetoric and review. Eight image rendering techniques consist of both 2-D and 3-D rendering are routinely applied to each stranded cetaceans for the biological health and profile investigation.The first one is multiplanar reconstruction, MPR. Display the default MPR from axial view, coronal view, and sagittal view after loading the series left click hold mouse button on the centers of MPR cross hairs to concurrently adjust the region of interest and slice in three MPR images click rotate, left click hold mouse button and drag the mouse to rotate the MPR images. Click pen, left-click hold mouse button and drag the mouse to adjust the location of image inside the panel.Click zoom, left click hold mouse button and drag the mouse to magnify or minimize the image. Select the appropriate present windows levels by clicking app one, app two, hea

image-rendering-techniques-postmortem-computed-tomography-evaluation

Research

JoVE Journal

Biology

Non-destructive volume visualization can be achieved only by tomographic techniques, of which the most efficient is the x-ray micro computerized tomography ( CT).

High Resolution 3D Imaging of Ex-Vivo Biological Samples by Micro CT

Visualization of the coronary vessels is critical to advancing our understanding of cardiovascular diseases. Here we describe a method for perfusing murine coronary vasculature with a radiopaque silicone rubber (Microfil), in preparation for micro-Computed Tomography (μCT) imaging.

Retrograde Perfusion and Filling of Mouse Coronary Vasculature as Preparation for Micro Computed Tomography Imaging

Implantation of autologous and allogeneic bone grafts constitute accepted approaches to treat major craniofacial bone loss. Yet the effect of graft composition on the interplay among neovascularization, cell differentiation and bone formation is unclear. We present a multimodal imaging protocol aimed to elucidate the angiogenesis-osteogenesis interdependence at the graft proximity.

Computed Tomography and Optical Imaging of Osteogenesis-angiogenesis Coupling to Assess Integration of Cranial Bone Autografts and Allografts

This method outlines the use of Quantum Micro-Computed Tomography (MicroCT) to assess cardiac morphology, function, perfusion, metabolism and viability with iodinated contrast agent in mice with experimentally-induced myocardial ischemia. The technique can be applied for non-destructive high-throughput longitudinal in vivo imaging of various animal models of human heart disease.

In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

We developed protocols and designed a custom apparatus to enable embedding of millimeter-scale specimens. We present sample preparation procedures with an emphasis on embedding in acrylic resin and polyimide tubing to achieve rigid immobilization and long-term storage of specimens for the interrogation of tissue architecture and cell morphology by micro-CT.

Rigid Embedding of Fixed and Stained, Whole, Millimeter-Scale Specimens for Section-free 3D Histology by Micro-Computed Tomography

Here, protocols for performing microfocus X-ray computed tomography (microCT) imaging of three marine invertebrate animals are explained in detail. This study describes steps such as sample fixation, staining, mounting, scanning, image reconstruction, and data analyses. Suggestions on how the protocol can be adjusted for different samples are also provided.

Microfocus X-ray CT (microCT) Imaging of Actinia equina (Cnidaria), Harmothoe sp. (Annelida), and Xenoturbella japonica (Xenacoelomorpha)

Here, we present a protocol to obtain high resolution micro computed tomography images of healthy and pathological large mammalian whole hearts with collagen-selective contrast enhancement.

Tissue Preparation Techniques for Contrast-Enhanced Micro Computed Tomography Imaging of Large Mammalian Cardiac Models with Chronic Disease

This novel protocol entails the quantification of cardiovascular calcification progression from serial micro positron emission tomography (PET)/micro computed tomography (CT) images in small research animals.

Novel Quantification Protocol for Cardiovascular Calcification Progression Using Longitudinal MicroPET/MicroCT Images

This protocol uses micro-computed tomography to enable the cost-effective quantification of lean mass, including skeletal muscle and visceral tissue, adipose tissue, and skeletal tissue in small animals. It distinguishes between lean and adipose tissue, which offers significant advantages for biomedical research, particularly in translational research in small animals.

Non-invasive Skeletal Muscle Quantification in Small Animals Using Micro-computed Tomography

Magnetic modulation biosensing system is utilized to rapidly, sensitively and simply detect biological assays, such as DNA molecules and proteins.

Rapid Homogeneous Detection of Biological Assays Using Magnetic Modulation Biosensing System

Aprenda técnicas de renderização de imagens em tomografia computadorizada pós-morte para avaliar a saúde biológica de cetáceos encalhados. Este método auxilia radiologistas e veterinários na interpretação de achados postmortem.

Técnicas de Renderização de Imagens em Tomografia Computadorizada Pós-Morte: Avaliação da Saúde Biológica e Perfil em Cetáceos Encalhados (Vídeo) | JoVE Journal

Image Rendering Techniques in Postmortem Computed Tomography: Evaluation of Biological Health and Profile in Stranded Cetaceans

Explorar mais vídeos