Transcript Medullary edema and enhancement: A characteristic

eP-24
Anant Krishnan1, Horia Marin2, C. Vemulapalli1,
R. Silbergleit1, R. Ceulemans2, J. Wilseck1, A. Wang1
Departments of Radiology:
1. Oakland University William Beaumont School of Medicine, Beaumont Hospital.
2. Henry Ford Hospital System, Detroit
The Authors have nothing to disclose
Purpose
Case 4
Materials and Methods
Case 5
Case 1
Results
Case 2
Discussion
Case 3
Conclusion
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1. To present a series of patients who presented
with medullary edema and enhancement on
MRI that were a result of underlying dural
arterio-venous fistulas (AVF).
2. To discuss the clinical presentations, and
findings on MRI that can confused with other
conditions and lead to delayed diagnosis.
Five patients between the ages of 35-72 that
presented at two teaching institutions over the
past five years with medullary findings from
dural AV fistulas are reviewed.
All patients initially underwent CT and MRI
examinations.
In two patients, MR spectroscopy and perfusion
was also performed. All patients eventually
underwent catheter arteriography.
B 1000 DWI
ADC Map
T1 PostContrast
MRI: Increased T2 signal
within the medulla with
corresponding mild
diffusion hyperintensity and
mild enhancement is seen.
FLAIR
FLAIR
TSE T2 weighted images
Closer review of T2
weighted images
demonstrates that
though there is diffuse
T2 signal, there is
sparing of the very
peripheral medulla
with additional linear
sparing areas (arrows)
also seen. This was not
initially recognized.
FLAIR
T1 Post-Contrast
Relative to the prior exam, in addition to the
T2 signal abnormality, and patchy
enhancement (arrows), there are now
distinctly prominent and enlarged vessels
(arrows) along the surface of the medulla and
upper cervical cord
• MR Spectroscopy
shows no
significant
elevation in
choline or
aggressive
appearance.
Spectroscopy TE 135msec
• Relative cerebral
volume (MR
Perfusion DSC) is
in fact slightly
decreased within
the medulla
Spectroscopy TE 35msec
A dural AVF was
suspected and
angiogram
recommended
Left external carotid injection
lateral (upper) and AP (lower)
views demonstrate a dural AVF
(in the wall of the left superior
petrosal sinus) fed by
meningeal branches of the
occipital, ascending pharyngeal
and middle meningeal arteries
with retrograde venous
drainage via petrosal vein to
the perimedullary veins
Late venous phase (lower)
also demonstrates
prominent pial
perimedullary veins,
running also to the
cervical cord as the
anterior and posterior
spinal veins.
Patient underwent a
combination
endovascular
embolization and surgical
resection of the dural
AVF.
Repeat Angiogram
showed no recurrence
Symptoms were
significantly improved
post surgery with
resolution of vertigo
At 3 year follow up,
patient has not had
recurrence in symptoms.
T2 weighted images
demonstrate
diffuse increased
signal in the
medulla but with
linear sparing
(arrows) creating a
geographic pattern.
An unusual vascular
structure is also seen
Intense enhancement
(arrows) is seen within
the medulla and
adjacent cerebellar
flocculus on the T1
weighted post contrast
images obtained with fat
saturation.
Post contrast MPRAGE sequence shows
the unusual vascular structure (separate
from the vertebrals). Medullary
enhancement is not as prominent as on
the T1 SE sequence
Based on MR imaging, a differential including dural AVF,
sarcoidosis, lymphoma was raised.
Patient underwent a 4 vessel cerebral angiogram that was
reported as ‘negative’ for a vascular malformation or fistula
A follow up MRI a month later showed an interval cerebellar
lacunar stroke (felt to be from the angiogram)
Multiple lumbar punctures failed to demonstrate cytologic
evidence of malignancy
MR perfusion and spectroscopy were requested as primary
concern was of a malignancy
CBV
DSC MR Perfusion: Prolongation in mean transit time (MTT) and mild decrease
in cerebral blood volume (CBV corrected for leakage) is seen within the
medulla
MR Spectroscopy 2D CSI: Lactate/Lipid
peak (arrow) without significant
elevation in choline is seen
TE 35msec
TE 35msec
TE 135msec
The authors at tumor board strongly suggested
a dural AVF despite the prior negative
angiogram (which had limitations and did not
include selective injections of the external
carotid)
A repeat cerebral angiogram with selective
external carotid injection and potentially spinal
injection was recommended
Lateral views from selective right ascending pharyngeal injection demonstrate arterio-venous shunting
with early opacification of bridging vein in the region of the anterior condylar vein (dotted arrow)
supplied by feeders (arrow)from the neuromeningeal division of the ascending pharyngeal artery.
Last image demonstrates dilated veins along surface of brain stem and upper cord ( white arrow)
draining both superiorly along the anterolateral surface of the pons toward the petrosal vein (yellow
arrow) and inferiorly towards the anterior spinal vein (green arrow) The tortuous vein (dotted arrow)
likelycorresponds to the original MRI seen anomalous venous structure.
Onyx was injected at the
neuromeningeal division
filling the fistula
No evidence of residual
dural AVF was seen at the
end of the procedure
Patient had improvement
in symptoms particularly
his dysphagia
5 month follow up
angiogram did not show
recurrence of AVF.
MRI obtained at this
follow up demonstrated
resolution of both edema
and enhancement. A
cerebellar stroke is also
seen on these images
• Patchy T2
hyperintensity
(arrow) with
peripheral sparing
and subtle
intramedullary
enhancement (arrow)
is seen.
• Serpiginous vessels
on the post contrast
sequence and flow
voids (interrupted
arrows) are seen
along the surface of
the medulla and
brain stem
CTA sagittal reformatted
images demonstrate
prominent
perimedullary and
ventral and dorsal
spinal veins.
Selective DSA of the occipital
artery (above) and mastoid
branch via microcatheter
(right) demonstrate the AVF in
the wall of the superior
petrosal sinus with retrograde
pial reflux via petrosal vein to
the perimedullary and spinal
veins (arrows).
Endovascular obliteration
of the DAVF was
performed using Onyx,
via mastoid branch of the
occipital artery.
Patient had significant
improvement in lower
extremity weakness with
mild residual LLE
weakness.
3 month follow up
angiogram did not show
recurrence
Sag FSE T2
Sag SE T1 Sag SE T1
Post contrast T1
Diffuse brain stem and spinal cord edema and enhancement was initially
diagnosed as transverse myelitis and managed with steroids, iv
Immunoglobulins and plasma exchange
5 months later, with progressive symptoms, she was seen at our institution
Post contrast T1
Ax FSE T2
There is mild expansion
and T2 signal change in
the medulla oblongata
and cervical spinal cord
(left), with associated
enhancement.
Subtle prominent vessels can be
recognized on the pial surface (arrow).
CTA (left) demonstrates venous congestion at the cervicomedullary junction.
Lateral DSA right internal carotid artery (middle image) demonstrates DAVF (arrow)
along the superior petrosal sinus supplied by the tentorial branch of the
inferolateral trunk. Lateral microcatheter DSA of meningeal branch of the occipital
artery (right image) demonstrates the DAVF with perimedullary venous drainage
(arrow).
The dural AVF was initially
treated with embolization
using Onyx via the occipital
artery supply. Residual
shunting was seen after
partial embolization without
successful penetration of the
Onyx on the venous side.
Surgical disconnection of the
dural AVF was performed
successfully the following day.
Patient had angiographic
follow-up one week after
surgery demonstrating
successful treatment of the
dural AVF.
Clinical recovery was very
limited with persistent
tetraparesis 12 months after
treatment.
MRI of the cervical spine (sagittal and axial T2 and post gadolinium T1) demonstrate
expansion of the cord and lower medulla with T2 hyperintensity (sparing the periphery),
faint enhancement and prominent ventral vessels along the cervical spinal cord (arrow).
DSA of the left vertebral artery (AP and lateral views) demonstrate arterio-venous
shunting consistent with a spinal dural AVF in the left C1 foramen (arrow) with
perimedullary venous drainage to the anterior spinal vein (double arrow).
Endovascular management
was deferred because of very
short arterial pedicle,
considered risky for
embolization. Surgical
management was initially
unsuccessful, with persistence
of the dural AVF.
Angiographic follow-up 6
weeks after initial surgical
treatment showed unchanged
appearance of the dural AVF.
Clinically , the symptoms
progressed to marked lower
extremity weakness and
bowel and bladder
dysfunction.
Second surgery performed 6
weeks later was successful in
treating the dural AVF. Clinical
examination was however
unchanged even after this
second surgery.
MRI demonstrated edema in the medulla as well as variable but
intense enhancement in all 5 cases.
The edema had a ‘geographic pattern’ with sparing of linear
areas including along the periphery of the medulla consistent
with vasogenic edema.
In 4/5 patients, some abnormal vasculature was present (often
in retrospect) on initial imaging
Initial concern was centered on the medullary 'mass like
appearance' and consequently consideration was given to
inflammatory and neoplastic conditions
Management was delayed in all 5 cases and empirical treatment
was attempted for alternative diagnoses
Incomplete, limited cerebral angiogram delayed identification of
dural AVF in one case
Diagnostic catheter angiography revealed the site of the dural
AVF to be along the superior petrosal sinus in 3 cases, in the
anterior condylar vein (one case) and along the C1 foramen (one
case).
In all cases, angiography demonstrated retrograde venous
drainage to the pial surface: via the petrosal vein (3 cases),
bridging condylar(one) and radicular vein(one). All cases had
venous congestion of the pial venous network at the surface of
the medulla and anterior and posterior spinal veins.
Successful endovascular embolization was performed in 2 cases.
Combined embolization and surgery performed in 2 patients.
Two surgeries were performed in 1 patient.
Three patients had near complete resolution of symptoms and
angiographically complete occlusion of dural AVF.
Two with significant delay in diagnosis and treatment did not
show significant improvement after removal of the fistula.
Dural arteriovenous fistulas cause increased venous pressure
resulting in pial venous congestion similar to changes seen in the
spinal cord from spinal dural AVF.1,2
This is compounded by venous outflow obstruction if an
underlying venous thrombosis/stenosis is present.
Congestion of the perimedullary venous plexus can have a
variable appearance given significant anatomic variation of the
perimedullary venous network.
Pial venous congestion in turn causes the peripherally sparing
vasogenic edema pattern seen on MRI and may extend into the
cord. This contrasts with the infiltrative process seen in brain
stem tumors and the territorial changes with diffusion restriction
seen in strokes.
Edema with peripheral
and symmetrical linear
sparing
Enhancement follows from the passive congestion and can vary in
intensity depending on MR acquisition technique.
The stasis not surprisingly can result in prolonged mean transit
time on MR Perfusion3,4. However there is variability in perfusion
parameters depending on whether there is a functional steal
(decreased CBV, MTT), venous congestion (prolonged MTT and
increased CBV) and ischemia (decreased in CBV but prolonged
MTT).4
Long standing congestion results in stasis of poorly oxygenated
blood, chronic hypoxia, which in turn results in cell degeneration
and cell death. On MR spectroscopy this would result in reduced
neuronal markers and increased lactate (a marker of anaerobic
metabolism).
Atypical perimedullary vessels are a hallmark of Cognard Type V
dural AVF but are not present in all cases (range from 37%5 to
76%1 of cases by MRI) . Similarly they may not be present in all
patients with intracranial fistulas on MRI.
When present, these vessels may be subtle and initially missed or
potentially disregarded as incidental.
The prominent enhancement and edema may lead to the initial
consideration of other diagnoses like inflammation, tumor,
demyelination, causing delay in identification of the fistula and
potentially irreversible complications.
Dural AVFs can be difficult to diagnose on MRI and
delayed or misdiagnosis can cause significant morbidity
The pattern of medullary edema with areas of
anatomic sparing, potentially with extension to upper
cord, and patchy enhancement is suggestive of a dural
AVF and should lead to close evaluation for unusual
vessels in the vicinity
When dural AVFs are suspected, a catheter arteriogram
to include the external carotid arteries and vertebral
arteries must be performed.
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5.
6.
Roelz R et al. Unilateral contrast-enhancing pontomedullary lesion due to an
intracranial dural arteriovenous fistula with perimedullary spinal venous drainage:
the exception that proves the rule. J Neurosurg. 2015 Dec;123(6):1534-9. PMID:
26047415
Crum B, Link M. Intracranial dural arteriovenous fistula mimicking brainstem
neoplasm. Neurology. June 2004. 2330-1.
Doege CA, Tavakolian R, Kerskens C, et al. Perfusion and diffusion magnetic
resonance imaging in human cerebral venous thrombosis. J Neurol2001;
248(7): 564–571
Kim DJ, Krings T, Whole-brain perfusion CT patterns of brain arteriovenous
malformations: A pilot study in 18 patients. AJNR Am J Neuroradiol 2011, 32:2061–
2066.
Haryu S, Endo T, Sato K, Inoue T, Takahashi A, Tominaga T: Cognard type V
intracranial dural arteriovenous shunt: case reports and literature review with
special consideration of the pattern of spinal venous drainage. Neurosurgery
74:E135– E142, 2014.
Intracranial dural arteriovenous fistula with venous reflux to the brainstem and
spinal cord mimicking brainstem infarction--case report. Li J et al. Neurol Med Chir
(Tokyo). 2004 Jan;44(1):24-8.