of the Neonate Spine

MRI & X-RAY
of the Neonate Spine
by Lynn Davis
A BRIEF HISTORY OF X-RAY
1895 - Wilhelm Röntgen begins investigating the
effects of electron beam emissions, and
accidentally discovers the “shadow” image of his
wife’s hand on a paper plate coated in barium
platinocyanide.
1895 - 1897 - Röntgen publishes three papers
discussing x-rays as a new type of medical
imaging.
1901 - Röntgen receives the Nobel Prize for
Physics for his discovery and research on x-rays.
(Nobel Lectures, 2012)
HOW DOES X-RAY WORK?
X-rays consist of electromagnetic waves, which are
similar to light waves only more energetic. This
means they are able to penetrate more materials.
A cathode emitter produces the beams, which
penetrate the subject to varying degrees and on to
a film that is behind the subject.
Various tissues absorb the rays differently, causing
a different level of exposure to the film.
Bone does not allow much of the beam to
transmit, therefore the bone on an x-ray is white.
Lung allows for most of the beam to be
transmitted through, causing it to be a darker gray
shade.
(Harris)
(McCoy)
HISTORY OF MRI
1970 - Raymond Damadian demonstrated differences in
cancerous tissue from rats with NMR (nuclear magnetic
resonance) imaging, the early name for MRI.
1973 - Paul Lauterbaur imaged the first living object with
MRI, a small clam.
1972 - Damadian applies for patent on his concept of MRI,
which he received in 1974.
1977 - With the help of graduate students, Damadian
constructs an MRI machine. It contained approximately 30
miles of niobium-titanium wire, and had a liquid helium
cooling system mounted on the top. An imperfect system,
the helium leaked miserably and ended up costing the team
about $2,000/week. This early MRI was called Indomitable.
1980 - The Fonar Corporation marketed a prototype based
on the Indomitable.
1982 - Fonar drops Damadian’s complicated MRI concept in
favor of Lauterbaur’s simpler version and continues
production of MRI machines, which started making their
way into hospitals.
(Wakefield, 2000)
(Ainali, 2012)
Winding 30 miles of niobium-titanium wire on two spools.
Raymond Damadian (left), Larry Minkoff (middle) and Michael
Goldsmith (right) posing with Indomitable in 1977.
One of two liquid helium cooling units.
All images: (Wakefield, 2000)
HOW DOES MRI WORK?
A strong magnetic field is created by passing an electric current through metal loops.
Coils in the magnet start to send and receive radio waves.
Protons in the body begin to align themselves, and once this occurs the radio waves are
absorbed by those protons. Then they begin to spin.
The energy that is released from these spinning protons emits an energy signal which varies
based on the type of tissue they reside in.
The signals are received by magnetic coils and sent to a computer for processing.
The processing computer then produces a “voxel” image by interpreting the radio waves
received, which is what we end up seeing in an MRI image.
http://www.youtube.com/watch?v=H5q79R9C-mk
(Kalapurayil, 2009)
BASIC ANATOMY
33 total vertebral bodies:
7 cervical vertebrae (C1-C7)
12 thoracic vertebrae (T1-T12)
5 lumbar vertebrae (L1-L5)
5 fused sacral vertebrae (S1-S5)
4 fused coccygeal vertebrae
(tailbone)
Intervertebral disks
(Hagen-Ansert, 2012)
("Houston orthopedic and," 2009)
BASIC ANATOMY
OF THE SPINAL CANAL
• Spinal
Cord
•
Body of the cord
•
Conus Medullaris (caudal end of cord)
•
Cauda equina (bundle of nerve roots
inferior to conus)
•
Filum terminale (tapering end of the
cord where the pia mater layer extends
into the sacrum and terminates the cord)
• Cerebrospinal
fluid
(Hagen-Ansert, 2012)
(Cunningham, 1903)
(Fitzgerald, 2011)
SPINAL PATHOLOGY
WHAT IS NORMAL?
T12
L1
Text
L2
L3
(Fitzgerald, 2011)
L4
On the MRI, conus is centrally located in canal at L1.
L5
On the US, the conus is centrally located at L2.
S1
Both are normal.
(Chandiran, 2011)
TETHERED CORD
A tethered cord is the adhesion of the spinal cord to
surrounding tissue, preventing free motion and growth.
MRI to left shows a tethered cord with a low-lying conus at
L4/L5 disk space, with a clear posterior adhesion.
US shows a tethered cord with low-lying conus at L5 (left
arrow) as well as a thickened echogenic filum (right arrow).
X-ray would be used to determine if there are any bony
abnormalities causing the low lying conus such as 11 rib sets.
L3
L4
L5
S1
(Gaillard, 2008)
(Howe, Johanek & Moore, 2007)
LIPOMA
A spinal lipoma consists of focal fatty tissue that can
displace the spinal cord, causing tethering.
MRI to left shows a hyperintense mass posterior to
the spinal cord cauda equina with no apparent
subcutaenous involvement.
US below shows hyperechoic mass posterior to the
cauda equina.
(Birmingham Children's Hospital, 2004)
(Howe, Johanek & Moore, 2007)
DORSAL DERMAL SINUS
A dorsal dermal sinus is the failure of skin closure
that leaves an open path through the spine. It may
or may not extend all the way to the spinal canal,
and it is very prone to infection.
The MRI shows a small hypointense tract starting at
the cutaneous layer extending all the way to the
spinal canal.
US below shows a hypoechoic canal extending from
the spinal canal to the superficial layers.
(Schenk, 2005)
(Schenk, 2005)
DIASTOMYELIA
Diastomyelia is a split/duplication of
the spinal cord within the canal.
Both MRI and US show an axial view of
a split spinal cord.
(Birmingham Children's Hospital, 2011)
(Fitzgerald, 2011)
INDICATIONS
Infants that may have a spinal ultrasound may have the following:
sacral dimple
palpable subcutaneous mass
tuft of hair
skin tag
hemangioma
(Thompson, 2010)
sinus tract
skin pigmentation spots (“port wine stain”)
infants with multiple congenital abnormalities
(Thompson, 2010)
PATIENT PREP
✤
NPO for sedation, if needed
All metal objects removed (patient and
guardian)
✤
Administration of contrast
✤
✤
Ear plugs/MRI-safe headphones
✤
MRI-safe incubator/immobilizer (if
needed)
✤
No prep needed for X-ray
(Fitzgerald, 2011)
(Troyka Med, 2012)
(Wilking, 2010)
MRI V. ULTRASOUND V. X-RAY
MRI
X-ray
Ultrasound
Advantages:
Advantages:
Advantages:
• Extreme detail resolution
• Non-invasive
• Non-invasive
• No ionizing radiation
• Painless
• No ionizing radiation
• No patient repositioning
• Excellent visualization of bony
• Dynamic imaging
• May show abnormalities that are
not able to be seen with US/Xray
because of bony structures
Disadvantages:
• Long scan times
structures
• Portable
• Fast exam
• Low cost
Disadvantages:
Disadvantages:
• Ionizing radiation risk,
• Operator dependent
particularly for pediatrics
• Sedation with some younger
children
• Loud noises that might scare
young patients
• Potential reaction to contrast
agents
("U.s. food and," 2012)
• Inability to view spinal structures
of older infants due to ossification
• Inability to safely visualize with
open skin lesions due to infection
(Fitzgerald, 2011)
• Cost
•Inherent dangers of very strong
magnets
(Jones, 2012)
HOW DO THESE MODALITIES
COMPLIMENT EACH OTHER?
Physicians often start with an ultrasound
when an anomaly is discovered in
neonates, since there is no radiation,
contrast or sedation needed for an exam.
If there are abnormal findings on the
ultrasound or if the infant spine has
ossified, an X-ray for bony abnormalities
may be ordered or an MRI for internal
severity exploration.
Combining all imaging modalities to aid
in diagnosis benefits the patient and
gives the doctor “the big picture.”
(United Medical Instruments, 2010)
QUESTIONS?
REFERENCES
Ainali, J. (Photographer). (2012). Mri. [Web Graphic]. Retrieved from http://www.thefeeherytheory.com/2010/06/29/mri/
Birmingham Children's Hospital. (Photographer). (2004).Intradural spinal lipoma. [Web Photo].
Birmingham Children's Hospital. (Photographer). (2011).Diastematomyelia. [Print Photo].
Chandiran, B. (Photographer). (2011). Tethered cord syndrome. [Web Photo].
Cunningham, D.J. Textbook of Anatomy (New York, NY: William Wood and Co., 1903)
Desktop Wallpaper HD. (Artist). (2010). Xray family. [Web Graphic]. Retrieved from http://www.desktopwallpaperhd.com/wallpapers/X-RayFamily-117852.html
Fitzgerald, K. (2011). Ultrasound examination of the neonate spine. Autralasian Journal of Ultrasound in Medicine, 14(1), 39-41.
Retrieved from http://www.minnisjournals.com.au/ajum/article/Ultrasound-examination-of-the-neonatal-spine-24
Gaillard, F. (Photographer). (2008). Diastematomyelia and tethered cord. [Print Photo]. Retrieved from http://radiopaedia.org/images/3742
Hagen-Ansert, S. L. (2012). Textbook of diagnostic sonography. (7th ed., Vol. 2). St. Louis, Missouri: Elsevier Mosby.
Harris, T. (n.d.). How stuff works. Retrieved from http://science.howstuffworks.com/x-ray.htm
Houston orthopedic and spine institute. (2009). Retrieved from http://houstonorthopedics.org/anatomy-spine.html
Howe, L. H., Johanek, A. J., & Moore, C. W. (2007). Sonography of the neonatal spine: Part 2, spinal disorders. American Journal of Roentgenology,
188(3), 739-744. doi: 10.2214/AJR.05.2160
Jones, J. (2012). Mri. Retrieved from http://radiopaedia.org/articles/mri
Kalapurayil, M. (2009, April 16). Medical news today. Retrieved from http://www.medicalnewstoday.com/articles/146309.php
Mayo clinic. (2012, Oct 24). Retrieved from http://www.mayoclinic.com/health/sacral-dimple/DS00753
McCoy, G. (Artist). (n.d.). Just as i thought, you have bones.. [Web Drawing]. Retrieved from http://www.cartoonstock.com/
cartoonview.asp?start=2&search=main&catref=ggm070813&MA_Artist=Not Selected&MA_Category=Not
Selected&ANDkeyword=xray&ORkeyword=&TITLEkeyword=&NEGATIVEkeyword=
Nobel Lectures. (2012, October 18). Nobelprize.org. Retrieved from http://www.nobelprize.org/nobel_prizes/physics/laureates/1901/
rontgen-bio.html
REFERENCES
Schenk, J. P. (Photographer). (2005). Imaging of congenital anomalies and variations of the caudal spine and back in neonates and small infants. [Print Photo].
Thompson, D. (2010). Spinal dysraphic anomalies; classification, presentation and management.Pediatrics and Child HEalth, 20(9), 397-403. Retrieved from
http://www.sciencedirect.com/science/article/pii/S1751722210000740
Troyka Med. (Photographer). (2012). Mr compatible baby incubator. [Print Photo]. Retrieved from http://www.troykamed.com/products.php?product=MRUyumlu-Bebek-Küvözü-%2d-Nomag
United Medical Instruments. (Designer). (2010).Neonatal/pediatric ultrasound. [Web Graphic]. Retrieved from http://ultrasoundvirtualdemo.com/ultrasoundspecialties/general-imaging/pediatric
U.s. food and drug administration. (2012, May 14). Retrieved from http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/
MedicalImaging/ucm298899.htm
Wakefield, J. (2000, June). Smithsonian magazine. Retrieved from http://www.smithsonianmag.com/science-nature
Wilking, R. (Photographer). (2010). Retrieved from http://rickwilking.photoshelter.com/image/I0000kBfRpsxreGc
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