How to Scan Your Mummy: Optimizing Radiologic Evaluation of Anthropologic Specimens

8/3/2019 How to Scan Your Mummy: Optimizing Radiologic Evaluation of Anthropologic Specimens

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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



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.

Documents

How to Scan Your Mummy: Optimizing Radiologic Evaluation of Anthropologic Specimens