MAGNETIC RESONANCE
IMAGING SPECTRUM OF
SPINAL DYSRAPHISMS
Abstract No. IRIA- 1037
INTRODUCTION
MRI plays an important role in characterising spinal dysraphisms because
of excellent soft tissue contrast and the ability to detect fat in the lesion.
T2 weighted images provide excellent contrast between the subarachnoid spaces and neural tissue while evaluating spinal dysraphisms.
AIM
• To study the MRI characteristics of spinal dysraphisms and to categorize
the lesions using non-contrast enhanced Magnetic resonance imaging.
2
MRI
MATERIALS
AND METHODS
3
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2 had only simple skin dimple
SPINAL DYSRAPHISM ON MRI
CLOSED
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RESULTS
CLINICAL SUSPICION OF
SPINAL DYSRAPHISM
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OPEN
1
MENINGOMYELOCELE
SUBCUTANEOUS MASS
PRESENT
ABSENT
2
2 LIPOMYELOCELES
1 LIPOMENINGOMYELOCELE
DISORDER OF SECONDARY
NEURULATION
1 INTRADURAL LIPOMA
1 FILAR LIPOMA
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DISORDER OF NOTOCHORDAL
INTEGRATION
1 CAUDAL AGENESIS
1 DIASTEMATOMYELIA
2 SEGMENTATION ANOMALY
1 DORSAL DERMAL SINUS
1 NEUROENTERIC CYST 3
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EMBRYOLOGICAL CLASSIFICATION OF SPINAL DYSRAPHISMS
PRIMARY
NEURULATION
4
T
E
R
M
I
N
O
L
O
G
Y
5
MENINGO-MYELOCELE
=
1C
#
%
1A
$
#
*
1B
T2 Sagittal image of spine (A) of a 1 day old
baby and Axial T2 weighted image at lumbar
spine (C) shows neural placode (#) extending
above skin surface due to expansion of
underlying subarachnoid space (=), which is
characteristic of myelomeningocele.
T2 Sagittal image of brain (B) showing thinned
out corpus callosum, tectal beaking (%),
elongated 4th ventricle and tonsillar
herniation ($) suggestive of Chiari 2
malformation
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Also note the cervical syrinx(*)
LIPOMYELOCELE
2A
2D
2B
2C
T2 (2A) and T1 weighted (2B) sagittal images showing fat intensity
lesion forming a subcutaneous mass in the back with intra-spinal
extension and a large intra-dural component
T2 axial ( 2C) image and schematic diagram (2D) showing the
lipoma-placode interface within the spinal canal suggestive of
a lipomyelocele
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LIPOMYELOCELE
2G
2H
2E
2F
T2 sagittal image (2E) and STIR (2F) image showing herniation of neural
tissue which is in contact with fatty tissue forming a subcutaneous mass
T2 axial image (2G) shows the lipoma-placode interface within the
spinal canal. Also note the posterior neural arch defect
T2 coronal image (2H) showing associated left hydronephrosis
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INTRADURAL LIPOMA
3A
3C
3D
*
L5
3B
T2 axial image (3D) showing the intradural
location with No spinal dysraphism or
subcutaneous mass
T2 (3A) and T1 (3B) weighted sagittal images of the lumbar spine showing
Fat intensity lesion intradurally. There is associated tethered cord (conus ending at L5 veretebral level
Coronal STIR image (3C) the lesion showing fat suppression (*)
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DORSAL DERMAL SINUS
4C
4A
4B
L4
4D
^
Sagittal T2 weighted (4A) and T1 weighted (4B) image showing a dorsal dermal sinus extending from the skin upto the
posterior meninges. Associated tethered cord (conus at lower border of L4). No fat intensity within spinal canal 4CSchematic diagram of dorsal dermal sinus with intradural dermoid.
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4D- T2 axial image showing the sinus tract (^)
DISORDERS OF MIDLINE NOTOCHORDAL
INTEGRATION neurenteric canal transiently connects the yolk sac to
the amnion via the primitive knot which regresses
during development of the embryo
• Dorsal enteric fistula and Neurenteric cyst- Incomplete
regression of neuro-enteric canal with abnormal
communication between bowel and spinal canal
• Diastematomyelia - when the persistent neuro-enteric
canal splits the spinal cord into 2 hemicords
DIASTEMATOMYELIA TYPE 1
WITH TETHERED CORD
5A
Separation of the spinal
cord into two hemicords is
referred to as
diastematomyelia.
hemicords are usually
symmetric AND Fuse back
distally
5B
L4
T2 axial image (5A) showing 2 hemicords with own dural sheath
separated by a fibro-osseous septum. Type 1 diastematomyelia. Note
the left hemicord syrinx. T2 sagittal image (5B)shows tethered cord
PANG Type 1 - the two
hemicords - individual
dural and arachnoid
covering separated by an
osseous or cartilaginous
septum
PANG type 2- there is a
single dural tube
containing two hemicords,
sometimes with an
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intervening fibrous septum
NEUROENTERIC CYST
Present as a POSTERIOR MEDIASINAL
CYSTIC MASS + VERTEBRAL ANOMALY
5B
*
5C
5A
T2 sagittal image (5A) shows a thoracic posterior mediastinal cystic mass,
with associated anterior vertebral cleft (*) in T2 axial image (5B). Also note
an incomplete diastematomyelia in a cranial axial section (5C)
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Partial SACRAL AGENESIS TYPE 2 (TETHERED
CORD)
Caudal agenesis can be of two
6A
6B
L4
types.
In type 1, there is a high
position and abrupt
termination of the conus
medullaris.
In type 2, there is a low
position and tethering of the
conus medullaris( a/w
thickened filum / lipoma)
Figure (6A) showing absent distal sacral
vertebral elements and coccyx. (6B) shows
the conus terminating at upper border of L4
suggestive of tethered cord
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COMPLEX DYSRAPHISM
7C
Type 2 diastematomyelia at thoracic level with
right hemicord syrinx
7A
7B
L5
7D
Vertebral segmentation anomalies
Long segment syrinx
Thickened filum terminale causing15
tethered cord. Associated Caudal agenesis
CRANIORACHISCHISIS – ENCEPHALOMENINGOCELE
WITH TETHERED DERMOID
T2 coronal image (A) showing herniation of the right hemi-brainstem via a
defect in the basi-sphenoid along with the right 7 and 8 cranial nerves.
T2 axial (8B)and T1 axial (C) image shows associated meningocele.
T1 axial image (a more caudal section) shows the fat intensity lesion
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adhered to the encephalo-meningocele.
CRANIORACHISCHISIS – ENCEPHALOMENINGOCELE
WITH TETHERED DERMOID
• Cranial dysraphism /Encephaloceles (1 / 40,000 LB) vs
spinal dysraphism 1-3 / 1000 LB
• Basal encephaloceles are rare (10% of encephaloceles) and they occur
mostly in the fronto-ethmoidal area. (>90%)
• So far in literature, no such case of brainstem herniation with
meningocele via a lateral basal, basi-sphenoid bony defect has been
described.
• We hence report this as the first case in Literature.
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CONCLUSION
• MRI is an excellent imaging modality for characterizing spinal
dysraphisms.
• MRI is indicated even in obvious open neural tube defects, contrary to
the conventional teaching, to look for associated Chiari malformation,
syringomyelia etc.
• MRI plays a role in the post-operative follow up of many lesions
especially to assess ascent of cord post de-tethering.
• It is important to diagnose closed spinal dysraphisms without
subcutaneous masses where no clinical mass is seen, as neurological
deficits can be arrested if diagnosed and treated early.
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CLINICO-RADIOLOGICAL CLASSIFICATION OF SPINAL DYSRAPHISMS
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REFERENCES
• Congenital Spine and Spinal Cord Malformations—Pictorial Review
Stephanie L. Rufener et.al. (2008) – AJR integrative imaging
• MRI findings in occult spinal dysraphisms– S. Morrthy et.al (IJRI2003)
• MR imaging in the tethered cord syndrome - Narasimhachan
Raghavan et.al. (AJNR- 1989)
• MRI in Infants and Children with Spinal Dysraphism -P D Barnes et.al
(AJNR -1986)
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