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Optimizing the
Radiologic Evaluation ofAnthropologic Specimens
Jason Johnson, MD, Christopher Filippi, MD, Deborah
Blom, PhD, Daniel Beideck, PhD, David Averill, DDS,Steven Shapiro, MD, George Ebert, MD, PhD.
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Disclosures
No authors have any disclosures.
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Topics
Anthropology History of Radiology in
Anthropology
Methods of Examination Optimization of Techniques Case Examples
3D reconstruction of a Native Americanartifact above an axial slide showing
central organic material.
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What is Anthropology?
The Study of Humanity Basic concerns: What defines humans Variations & differences among different groups of
humans
Evolution and its influence on social organization andculture
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Methods of Anthropologic Examination
Necropsy* Microscopy* Radiography Fluoroscopy Electron Microscopy* Carbon Dating* CT DNA* MRI
The last fifty years have seen an upsurge ofmummy research all over the world. This is
largely the effect of the rapid development ofmedical science and technology.
Various methods primarily designed for the
examination of living patients proved to be
equally successful for the investigation of
human remains.
Egyptian Mummies. Maarten J. Raven & Wybren K. Taconis.
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History of Radiology in Anthropology
Advances in non-destructive techniquesfor evaluation of mummies closely
parallels advances in medical imaging.
1895 - Wilhelm Roentgen made hisfamous discovery, an achievement that
earned him the first Nobel Prize in
Physics in 1901. The picture (right) is the
very first roentgen photo made of a
human body: Mrs. Roentgens hand.
Roentgens revolution by Vivian Grey
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History of Radiology in Anthropology
Rajiv Gupta at MGH (2007) usesstate-of-the-art fpVCT technology to
raise standards of radiologic
evaluation of Egyptian mummies.
800 non-overlapping CT sections at120 kV and 50 mA at 194 micron
isotropic resolution and 1024 matrix
were generated.
R. Gupta. AJNR Am J Neuroradiol 29:70513
R. Gupta. AJNR Am J Neuroradiol 25:141724
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Optimization of Techniques
Focus on CT
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CT Optimization
An optimized protocol for a specific study must takeprinciples into account to give proper balance among
detail, low noise, and [patient] exposure.
Two important characteristics of CT that affect the ability tovisualize anatomic structures and pathologic features: Blur - Increased blurring reduces the visibility of small
objects (image detail)
Noise - increased visual noise reduces the visibility oflow-contrast objects.
Mahesh M Radiographics2002;22:949-962
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Blur
Sources of blurring in CT: size of the sampling
aperture (which can be
regulated by the focal spotsize and the detector size)
size of the voxels reconstruction filter
selected. Use of small voxels and edge-
enhancing filters helps reduce
blurring and improves thevisibility of fine details.
Mahesh M Radiographics
2002;22:949-962
Sprawls P Radiographics1992;12:1041-1046
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Noise
Image noise limits the visibility of low-contrast structures. Determined primarily by the # of photons used to make an
image (quantum mottle).
Noise is generally reduced by (if all other parameters areconstant):
increasing the tube voltage increasing the current increasing the scan time
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Noise
Noise is also reduced by increasing voxel size(i.e., decreasing matrix size, increasing FOV, or increasing
section thickness).
Noise does not change with pitch in helical CT scanning. Typical noise of a modern CT is ~3 HU (i.e., 0.3%
difference in attenuation coefficient).
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Traditional vs Optimized
Matrix: 512
mAs: 915
Thickness:3.0 mm
KV: 120
SameWW/WL
Matrix: 512
mAs: 300
Thickness:3.0 mm
KV: 120
Matrix: 1024
mAs: 300
Thickness:0.9 mm
KV: 80
Matrix: 1024
mAs: 300
Thickness:0.9 mm
KV: 120
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Spatial Resolution
The ability to discriminate betweenadjacent objects.
A function of: pixel size focal spot size detector size image reconstruction filter.
If the CT FOV is d and the matrix size is M, the pixel size is d/M.Typical resolution in CT scanning ranges from 0.5 to 1.5 lp/mm.
In practice, the pixel size is smaller than the limiting resolutionimposed by the finite sizes of the focal spot and x-ray detectors.
Detail (bone) reconstruction filters must be used to achieve thebest spatial resolution.
Mahesh M Radiographics 2002;22:949-962
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Traditional vs Optimized
Matrix: 512
mAs: 382
Thickness:0.9 mm
Bone Filter
Similar:KvPWW/WL
Matrix: 1024
mAs: 340
Thickness:0.67 mm
Very Sharp Filter
Matrix: 512
mAs: 352
Thickness:3.0 mm
Bone Filter
FOV 223Pixel = 0.22mm
FOV 286Pixel = 0.56mm
FOV 500Pixel = 0.98mm
pixel size = d/M
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Radiation risk
100 Gy = cerebrovascularsyndrome10 Gy = Typical LD 50/5
(i.e., gastrointestinal death)
4 Gy = Typical LD 50/60in humans.
1 Gy = Estimated doseto double the natural
mutation rate.
Theoretic risk of DNA damage.Research suggests major
cause for aDNA degradation is
environmental (temperature).
Dehydrated remains alongwith diagnostic energy
photons unlikely to directly act
on aDNA.
Deceased
Variant STEVOR Gene Sequences Obtained From DNA Extracts ofTutankhamun
Living and Non-Living
Living
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Information Content of images =number of pixels X number of bytes.
Standard CT slice with 512 X 512 matrix and2 byte coding requires 0.5 MB of memory(512 X 512 X 2).
CT obtained at 1024 matrix = 2 MB of memory(1024 X 1024 X 2).
Head CT Example
Routine 5 mm = 28 slices = 14 Mb. FAHC 3 mm = 115 slices = 57 Mb. Fleming mummy (0.67/0.38 mm) = 368 slices
= 736 Mb.
Fleming mummy data footprint = approx 40Gb.
50%
100%
300%
800%
600%
800%
normalresolution
Ultra-high resolution imaging (except for bottom left)
IT: The Silent Partner
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Missisquoi jar
Peabody Essex mummy
Fleming mummy
Case Examples
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Finding at edge of knownNative American burial site
dating to over 2,000 years.
Appearance was immediatelysuspicious for Native American
burial remains.
Due to religious beliefs,identifying contents non-
invasively of great importance.
Missisquoi Jar
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Options for Examination
State anthropologists believedthe vessel to represent a
sacred burial item. Question remained about
whether the vessel contained
human remains.
CT thought to be best choicefor non-invasive examination.
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Several cremation burials found nearthe vessel revealing that mortuary
practice was used in the past.
This body could may have beencremated on a bed of pebbles helping
to create a hotter fire to burn the body
and subsequently gathered with the
cremated remains.
Pottery vessels in the Northeast wereusually made with crushed quartz,
sand or sometimes crushed shell.
Missisquoi Jar
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Lower density areas identified|with CT
Thought to either represent crematedremains versus vegetable mattergathered with contents
CT data used to guide limitedexcavation
7 cm diameter sample revealed Observed two thin roots Brown soil with greater organic
material compared to other contents
No evidence of bone or any unusual material.
Residual Organic Material?
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Mummy of a man who died around 50 CE,when Roman rulers controlled Egypt.
Found by George Peabody in Fayum,Egypt on May 9, 1901.
Body wrapped in linen, now discolored bythe resins and ointments used during
mummification.
Painted designs on his coverings showprotective gods and goddesses, including
a winged sun disc and the kneelinggoddess Nut.
The gold of his mask indicates hisascendancy into the realm of the gods.
Peabody Essex Mummy
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Peabody Essex Museum
Methods of Examination
CT Body 120 KV, 200 mAs, 2.5 mm
CT Head 140 KV, 300 mAs, 1.25 mm 3D reformations
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Identity: Unknown, Egyptian Dated: Roman Period (30 BCE-350 CE) Material: Linen, cartonnage, human
remains, wood, pigment, gilding 9 in. x
65 in. x 14 5/8 in
Catalog ID: Peabody Essex Museum,Salem, Massachusetts, 33.2003L
Age at death: young adult
Peabody Essex Mummy
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Excerebration
Trans-sphenoidal widelyconsidered as only approach
applied.
Sub-occipital and foramenmagnum also described.
Likely removed because: Concern for rapid
putrefaction. Not felt important for afterlife. The brain was removed with a
trocar, through a trans-sphenoidal
approach, and discarded.
Marx, M Radiographics 1986;6:321-330
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Routes of excerebration
Nasal Foramen
magnum
In all 7 cases with an intact cribiform plate, remains of the occipital
lobes of the brain were still in situ. In 2 of these cases extensive
destruction of the skull base and upper part of the cervical vertebral
column was noted.Egyptian Mummies. By Maarten J. Raven, Wybren K. Taconis.
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Fleming Mummy
Egypt Mummy In Mummiform
Coffin, 6th century BC
Wood, Gesso 186 cm Length 1910.3.119 Museum
purchase
(Cairo Museum)
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Fleming Mummy
Methods of Examination
Portable radiography1937
Ultra-high resolution, highphoton CT from head to
toe. 2010
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Fleming Mummy - Radiographs
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Age
14 - 17 years based on Initial formation of M3 root Acetabulum fusion Unfused metatarsals
Scapular evaluation willlikely further narrowthe age range.
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Foramen Magnum Excerebration
Turbinates, ethmoid aircells, sella intact.
Extensive destruction ofthe upper cervical spine.
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Right Frontal Bone Fracture
Distinguishing betweenperimortem and postmortem
injuries is difficult.
Living bone fractures differentlythan dried bone.
Fresh bone tend to splinter andproduce irregular edges.
Dried bone is more brittle andmore likely to shatter into smaller,more regular fragments.
Curling or uplifting associated with cut markson fresh bone is much less likely to occur in
bone that is dry and friable.
N Sauer. Forensic Osteology. 1998.
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Review
Anthropology History of Radiology in Anthropology Methods of Examination Optimization of Techniques Case Examples
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Conclusion
Abenaki Vessel and Fleming Mummyexamination at FAHC/UVM led to
changing protocol for CT evaluation of
forensics cases.
Outcome measures should dictatescanning parameters.
Artifact lack of motion and acceptanceof higher photon imaging techniquesare vital points for image optimization.