the application of digital radiographic analysis to skeletal assemblages

THE APPLICATION OF DIGITAL RADIOGRAPHIC
ANALYSIS TO SKELETAL ASSEMBLAGES
BABAO Funded 2011
DDR undertaken by Mark
Farmer/Reveal Imaging Ltd.
and Jerry Conlogue,
Quinnipiac University, USA
Jelena Bekvalac, Centre for Human Bioarchaeology, Museum of London, jbekvalac@museumoflondon.org.uk
Gaynor Western, Ossafreelance, info@ossafreelance.co.uk
Radiography can be defined as ‘That special branch of medicine employing ionizing radiant energy in the diagnosis and treatment of disease.’ (Brogdon, B. G., 1998)
Introduction
The analysis of human skeletal remains provides a wealth of data including vital evidence of pathology. The diagnosis of diseases is critical to understanding their occurrence in the past but can be hindered by a wide range of factors,
including the limited observability of macroscopic pathological changes within bone. This reduces the ability to diagnose conditions according to clinical criteria, the databank for which is currently growing rapidly with expanding use
and archiving of digitally recorded clinical cases. Direct digital radiography (DDR) is an exciting new development for palaeopathological investigation that enables rapid, relatively inexpensive analysis of complete skeletal assemblages
that is financially viable and can be easily incorporated into commercial and academic projects as well as museum archives and learning resources.
Advantages of Digital Images
Advantages of DDR in Palaeopathology
Robustness: Digital Images do not deteriorate physically or chemically over time
Consistency: Digital Images allow true reproduction quality from copy to copy and from generation to generation
Flexibility: Digital Images allow a variety of manipulation e.g. magnification, cropping, scaling etc.
Featured Contents: Digital images may be easily linked to databases i.e. DICOM
Communicability: Access, transfer and storage of digital images is possible across a range of internet enabled media.
(Indrajit I.K. and Verma, B. S., 2007)
Much greater resource of clinically observed diseases than dry bone specimens: the volume of
clinical digital data is increasing (Hines ,E., Rock, C. and Viner, M. D. 2007).
Wider range of pathological conditions with radiographic expression than observable
macroscopically
Confirmation of diagnoses by radiographic signs is more accurate and robust
Easier and more objective recording of lesions and can be measured in 2D digital images
Diagnosis by radiology from the clinical base may illuminate the variety of macroscopically
observable skeletal expression of a disease
Technique is minimally invasive, rapid and cost effective with portable equipment available (Hines,
Rock and Viner, 2007).
Clinical pattern recognition can aid with diagnosis in incomplete or disarticulated remains.
Acquisition and display are separate processes
Images can be accessed simultaneously at any workstation
Viewing stations can be set up in any location
Ability to use digital image archives rather than film libraries
Availability of soft copy reporting
No manual handling of cassettes
Lower running costs from use of soft-copy only
(Stewart Whitley, A., Sloane, C., Hoadle, G., Moore, et al. 2005)
Currently, more than 80% of ante-mortem radiologic examinations obtained for clinical purposes are
comprised of routine x-ray examinations and roentgenograms (x-rays) (Brogden, 1998 p.160).
Conventional radiography remains the backbone of musculoskeletal radiology despite the advent of
newer techniques such as CT, MRI and PET. (Burgener, F. , Kormano, M. and Pudas, T. 2006).
After Medical Imaging Resources http://www.mir4imaging.com/PACS_california.html
Application to Skeletal Assemblages
When using and accessing new applications it is important to have the right tools available to enable them to have
optimum benefit and accuracy.
In the clinical setting, images are managed and
communicated via PACS (Picture Archiving and
Communication System), which is a protocol-based
standard to facilitate the transfer of digital images and
associated information between devices (Hines et al.
2007, p.25).
The extensive digital datasets in the clinical field already
have in place standards & protocols that are supported by
Digital Imaging and Communications in Medicine –
DICOM. This means that radiographs produced in DICOM
format from both clinical and palaeopathological fields can
be readily stored and accessed within the same database
management system.
PACS can be effectively employed within palaeopathology to allow shared access to an international resource of
digitised skeletal pathology between universities, museums, hospitals and the commercial sector.
sector
DDR was tested on two contrasting skeletal assemblages to assess the new application from a biological
anthropologist’s standpoint and gauge any difficulties faced when utilising digital images for enhancing pathological
diagnosis. The collections examined were St Bride’s Crypt, London and Worcester Royal Infirmary, UK. The former
consisted of well preserved articulated individuals whereas the latter was fragmentary, disarticulated surgical waste
and anatomical specimens. We noted that the following considerations of DDR’s application to skeletal assemblages:
Recording and Interpretation
Radiographs represent skeletal structure as the contrast
between areas of higher and lower density. Therefore, the
recording of radiographic images in skeletal pathology
relate to two fundamental indicators of bone form, namely
osteopenia and osteosclerosis. These can be generalised
or localised expressions of disease. The nature and
distribution of these changes are key to diagnosis.
1) Permeative
Lesions:
these
represent the most aggressive bone
destruction pattern with rapid
growth.
This
lesion
merges
imperceptibly with the normal bone.
Infiltrative in the bone marrow
and/or the cortex, which may present
as cortical striation or tunnelling.
Found in acute osteomyelitis and
rapidly developing osteoporosis.
The location and extent of osteopenia and
osteosclerosis should be recorded prior to
interpretation. A helpful categorisation of the pattern of
bone changes may be found in Burgener, F. , Kormano,
M. and Pudas, T. 2006 Bone and Joint Disorders, 2nd
Edition. Thieme, Stuttgart and New York, p.75:
2) Moth-Eaten Lesions: a poorly
demarcated focus of bone
destruction with a long zone of
transition
from
normal
to
abnormal bone indicating its
aggressive nature and rapid growth
potential.
Malignant
bone
tumours,
osteomyelitis
and
eosinophilic granulomas present
with this type of bone destruction.
Advantages:
Ease of application using mobile radiographic equipment
•
•
Benefit of immediate visibility of the image and ability to instantly re-take if required
•
Rapidity of imaging: c. 180 images in one day or 10+ complete skeletons
•
Ability to confirm and find alternative differential diagnoses from the radiographic literature
•
Identification of diseases with no macroscopic evidence
Considerations:
•
Consistency in positioning of the elements
•
Information relating to the burial environment for post mortem damage & degradation
•
Familiarisation with normal bone structure and interpreting radiographs (Guides online &
published: see Refs. 3,6 & 7 as examples)
•
When viewing the radiograph to have the element at hand to compare
•
When publishing to have the two images together for visual comparison
•
Use of a recognised, standardised classification system to describe basic changes observed prior
to diagnosis
•
Difference of pathology classifications between the radiographic and palaeopathological
literature
DDR and radiographic analysis should be integral to diagnosis frameworks within palaeopathology
A major advantage of DDR application is the ability to discover lesions with no external manifestations.
For example, amongst the Worcester Royal Infirmary assemblage, 6.7% of elements exhibited
radiographic lesions only. A further 50.4% with macroscopic changes could be newly or more firmly
diagnosed with the aid of clinical radiographic evidence.
Osteopathia
Striata:
Undetectable
without
radiography, this rare disease, indicated by radiodense
vertical striations, was discovered in element [801] from
the Worcester Royal Infirmary, UK. Although generally
asymptomatic, it can be associated with Goltz syndrome
or Focal Dermal Hypoplasia (FDH), for which OS is a key
clinical sign. FDH is a rare X-linked dominant disease
lethal in the male foetus. About 90% of those affected are
female. It is outwardly evident though extensive nodular,
reddened skin defects that can ulcerate. A suite of
skeletal defects may also be present throughout the body.
3) Geographic
Lesions:
well
defined margin separating it clearly
from the surrounding normal
bone. Geographic lesions are
usually benign, especially when
they are marginated by a sclerotic
rim. Multiple myeloma and
metastases, however, frequently
present as geographic lesions
without sclerotic borders.
Osteoblastic Carcinoma: The skeletal remains of John
Paul Rowe, St Bride's crypt [SB79 102] manifested lesions
throughout his skeleton indicative of osteoblastic
metastatic carcinoma, most probably prostate cancer.
All the vertebrae were markedly affected & displayed
gross osteoblastic lesions. Radiographs of osteoblastic
metastases can vary from barely visible, poorly defined
areas of increased densities in some vertebrae to almost
complete sclerosis ‘ivory vertebra’2. The x-rayed
vertebrae displayed these characteristic changes,
including the classic ivory vertebra, providing a
corroborative diagnosis for the osteoblastic carcinoma.
Conclusion
Permeative
Aggressive/Acute
Moth Eaten
Geographic
Benign/Chronic
Periostitis should be recorded to convene with current radiographic standards to aid interpretation and diagnosis.
Differentiation should be made between Solid and Interrupted Periosteal Reactions, with further classification of thin,
thick, straight, elliptical, undulating, laminated, perpendicular, amorphous and the presence of periosteal cloaking.
There is much that can be gained from the use of DDR in its application for skeletal assemblages. Many
protocols and standards are already in place within the medical and clinical field that can be actively
utilised by biological anthropologists. Large accessible datasets of skeletal assemblages could be
established and accessed following DICOM/PACS for both articulated and disarticulated collections.
There are factors to consider as with all applications but if there is a consistency in the approach to its
use then the interpretative value of the results would be manifold and of wide-spread benefit.
Collaborations between radiologists and biological anthropologists are key to being able to develop
more fully the analysis & interpretation of palaeopathological cases. This has the potential for enabling
an embedded scientific foundation for diagnostic methods in palaeopathology.
References
1.
Brogdon, B. G., 1998, Forensic Radiology, CRC Press, USA.
3.
2.
Burgener, F. , Kormano, M. and Pudas, T. 2006 Bone and Joint Disorders, 2nd
Edition. Thieme, Stuttgart and New York.
4.
Chhem, R. and Brothwell, D. 2008. Paleoradiology: Imaging Mummies and Fossils.
Springer, Berlin.
Hines, E., Rock, C. and Viner, M. 2007. Radiography in Thompson, T. and Black, S.
(eds) Forensic Human Identification: An Introduction. CRC Press, USA.
5.
6.
Indrajit I.K. and Verma, B. S., 2007. Digital Imaging in Radiology Practice: An
introduction to a few fundamental concepts. Journal of Radiological Imaging, 17,
pp. 230-6.
Matshes, E., Burbridge, B., Sher, B., Mohamed, A. and Juurlink, B., 2005. Human
Osteology and Skeletal Radiology: An Atlas and Guide. CRC Press, USA.
7.
Moeller, T. and Reif, E. 2000. Pocket Atlas of Radiographic Anatomy 2nd ed. Thieme,
Stuttgart.
8.
Stewart Whitley, A., Sloane, C., Hoadle, G., Moore, A. D. and Alsop, C. W., 2005.
Clark’s Positioning in Radiography. 12th edition. Hodder Arnold, London.