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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6009_Библиотеки_им_академика_М_И_Перельмана.pdf
Type 4 Vascular Malformation (Arteriovenous Fistula)
KEY FACTS
TERMINOLOGY
• Synonyms: Perimedullary fistula; type 4 spinal vascular
malformation, pial arteriovenous fistula (AVF)
• Direct intradural extramedullary arterial/venous
communication from anterior or posterior spinal artery to
Vascular Disorders
draining vein without capillary bed
IMAGING
• Hyperintense cord + flow voids
• Intradural location for fistula, adjacent to cord
• Draining veins may be pronounced on dorsal or ventral
surface of cord
• Feeding vessel from anterior or posterior spinal artery
connects directly with spinal vein
TOP DIFFERENTIAL DIAGNOSES
• Normal CSF flow artifact
• Type 1 dural fistula
• Lumbar canal stenosis with tortuous intradural roots
(Left) Coronal oblique graphic
of the thoracic cord shows the
intradural site of
arteriovenous fistula (AVF,
type 4) on the dorsal cord
surface with diffuse venous
engorgement . A fistula is
more typically along the
ventral cord surface. (Right)
Sagittal T2 MR shows multiple
serpentine intradural
extramedullary flow voids
dorsal to the thoracic cord,
plus focal cord abnormality
due to a high-flow aneurysm.
• Intramedullary neoplasm
PATHOLOGY
• 4-A: Small AVF with slow flow, mild venous enlargement
• 4-B: Intermediate AVF, dilated feeding arteries; high flow
rate
• 4-C: Large AVF, dilated feeding arteries; dilated, tortuous
veins
• Associations
○ Hereditary hemorrhagic telangiectasia
○ Cobb syndrome
○ Klippel-Trénaunay-Weber syndrome
CLINICAL ISSUES
• > 90% of patients present with neurological deficits
○ Hemorrhage at presentation in 36%
• Embolization or surgical resection based upon anatomy and
size: Surgical resection, surgical resection or embolization,
embolization
330
(Left) Sagittal STIR MR shows
a long segment of cord
hyperintensity with ill-defined
flow voids along the ventral
cord surface. There is a more
focal area of low signal, which
at angiography was a highflow aneurysm . (Right) AP
view of a catheter angiogram
(arterial phase) shows a
prominent segmental feeder
to the cord, which shunts
into the coronal venous
plexus, with no intervening
nidus. There is high-flow
aneurysm at the fistula site
.
Posterior Fossa Dural Fistula With Intraspinal Drainage
KEY FACTS
Vascular Disorders
TERMINOLOGY
• Dural arteriovenous fistula (DAVF): Anomalous connection
between dural arteries and venous sinuses &/or cortical
veins without presence of normal intervening capillary bed
• Rare DAVF variant has preferential venous drainage
inferiorly into spinal veins
IMAGING
• Increased T2 signal in upper cervical cord/medulla with
abnormal perimedullary flow voids
• Fistula located in posterior fossa with symptoms related to
site of venous drainage (myelopathy)
• Catheter angiography remains gold standard
TOP DIFFERENTIAL DIAGNOSES
• Spinal DAVF
○ Cord signal change and flow voids may look identical to
posterior fossa DAVF with intraspinal drainage
• Demyelinating disease
○ Cord enhancement and increased T2 signal but no
abnormal perimedullary flow voids
CLINICAL ISSUES
• Myelopathy related to venous hypertension secondary to
AV shunting and insufficient venous drainage of spinal cord
• Symptoms tend to be chronic and progressive
○ 25% have acute onset of neurological disorder
• Good prognosis for improvement of symptoms or
complete recovery
• Occlusion/resection of fistula by endovascular means or
open surgery
DIAGNOSTIC CHECKLIST
• Catheter angiography still required for exclusion of DAVF
even if negative MRA
• DAVF clinical manifestations related to anatomical
distribution of draining veins, not fistula site
• Cognard type V fistula presenting symptoms relate to
dysfunction of spinal cord rather than brain
(Left) Sagittal T2WI MR shows
extensive cord hyperintensity
and mild fusiform cord
expansion from C1 to C4 .
There are multiple abnormal
pronounced perimedullary
flow voids ſt. Dilated draining
veins are present in the
posterior fossa . (Right)
Following contrast
administration, sagittal T1WI
MR shows diffuse
enhancement of the upper
cervical cord from the
cervicomedullary junction to
C5 ſt. Multiple intradural
extramedullary flow voids
are present.
(Left) Axial FLAIR shows
abnormal T2 hyperintensity
within the right side of the
medulla ſt. The diffusion
study was normal (not shown).
The abnormality within the
medulla, coupled with the
prominent veins, prompted the
recommendation for a
catheter angiogram to exclude
a dural fistula. (Right) Arterial
(left) and venous (right)
phases of left vertebral
injection show a dural fistula
supplied by posterior
meningeal branches ſt with
extensive intraspinal draining
veins both dorsal and
ventral to the cord.
331
Cavernous Malformation
KEY FACTS
TERMINOLOGY
• Vascular lesion with lobulated, thin, sinusoidal vascular
channels and no interspersed neural tissue
IMAGING
• Locules of blood with fluid-fluid levels surrounded by very
Vascular Disorders
T2-hypointense rim
• Spinal cord uncommon site: 3-5% of all cavernous
malformations (CMs)
• Round, heterogeneous signal abnormality, well-defined
margins
• Brain MR to identify supratentorial lesions
TOP DIFFERENTIAL DIAGNOSES
• Intramedullary neoplasm
• Arteriovenous malformation
• Multiple sclerosis
PATHOLOGY
• Cervical (40%), thoracic (50%)
(Left) Sagittal T2WI MR shows
a small heterogeneous
intramedullary lesion ſt at
the C1 level. There is slight
cord expansion but no
adjacent edema. Mass effect &
intrinsic cord edema generally
occur with more acute
hemorrhage. (Right) Sagittal
T1WI MR shows the typical
appearance of a cavernous
malformation of the spinal
cord. A heterogeneous, slightly
expansile intramedullary
lesion is seen at the C2-3 level
ſt. A faint salt & pepper
pattern is present from
repeated hemorrhages &
hemosiderin deposition.
○ Discrete, lobulated blue-reddish brown (mulberry-like)
nodule
○ Vascular spaces with single layer of endothelial cells
○ No intervening neural tissue between vascular spaces
• Multiple (familial) CM syndrome (20%)
○ Familial CMs are at high risk for hemorrhage and
formation of new lesions
○ Mutations in 3 genes (CCM1, CCM2, CCM3) implicated in
familial forms
CLINICAL ISSUES
• Typically occurs in 3rd-6th decades
• M:F = 1:2
• Broad range of dynamic behavior (may progress, enlarge, or
regress)
• Surgical resection is mainstay of symptomatic CM
• Variable outcomes in literature: 50-66% improve, 28%
stabilize, and 6% deteriorate postoperatively
332
(Left) Sagittal T2WI MR
depicts a classic, mixed
hyperintense (popcorn or salt
and pepper) lesion surrounded
by a hypointense rim ſt from
hemosiderin. Cavernous
malformation was found at
surgery. (Right) Axial T2* GRE
MR exhibits a cavernous
malformation in the cervical
cord as a large area of low
signal from susceptibility
artifact ſt from the blood
byproducts. There should be
blooming of this type of lesion
with longer echo times.
Spinal Artery Aneurysm
KEY FACTS
Vascular Disorders
TERMINOLOGY
• Fusiform or saccular dilatation of artery supplying spinal
cord, particularly anterior spinal artery but including
radiculomedullary branches
IMAGING
• Catheter spinal angiography required for diagnosis
TOP DIFFERENTIAL DIAGNOSES
• Hemorrhage from intramedullary tumor
• Hemorrhage from spinal vascular malformation
PATHOLOGY
• Most commonly associated with spinal vascular
malformations
• Coarctation of aorta
• Arteritis (including inflammatory etiologies, such as syphilis
or mycotic)
• Fibromuscular dysplasia
• Pseudoxanthoma elasticum
• Klippel-Trenaunay-Weber syndrome
• Idiopathic
○ Tend to be fusiform in shape without defined neck (as
seen commonly with intracranial aneurysms)
○ Often unrelated to arterial branching sites
CLINICAL ISSUES
• Presenting symptoms include back pain, headache,
vomiting, weakness, paraparesis, and paralysis
• Treatment may include clipping if neck is present or
trapping with occlusion of parent vessel or wrapping with
muslin
• Isolated reports of coil embolization of spinal aneurysms
• Spontaneous regression reported in aneurysms with
inflammatory etiology
DIAGNOSTIC CHECKLIST
• Unlike intracranial aneurysms, risk of surgical treatment of
ruptured aneurysm may exceed expected benefit
(Left) Axial T1WI MR shows
high signal intensity blood
throughout the subarachnoid
space ſt in this patient with
spinal aneurysm. (Right)
Anteroposterior catheter
angiography with injection of
the left-sided intercostal
artery shows filling of a small
anterior spinal aneurysm ſt.
(Left) Lateral catheter
angiography with injection of
the thoracolumbar intercostal
artery shows filling of a
fusiform anterior spinal artery
aneurysm ſt. (Right)
Anteroposterior catheter
angiography 3D spin study
shows small outpouching of
contrast off of the ventral
medial aspect of the left
vertebral artery due to an
aneurysm at the origin of the
anterior spinal artery ſt.
There is a small amount of
reflux extending down the
right vertebral artery .
333
Spinal Cord Infarction
KEY FACTS
TERMINOLOGY
• Spinal cord ischemia
• Cord infarction 2° to vessel occlusion (radicular artery)
IMAGING
Vascular Disorders
• MR with contrast, + diffusion
• Hyperintensity on T2WI within cord; central owl's eye
pattern
○ Slight cord expansion in acute phase
• Hyperintense central gray matter or entire cross-sectional
area
• DWI: Hyperintense, as in brain infarcts
TOP DIFFERENTIAL DIAGNOSES
• Multiple sclerosis
• Transverse myelitis
• ADEM/viral myelitis
• Neuromyelitis optica
• Type I dural fistula
(Left) Axial T2WI MR in a case
of hypoxic-ischemic
encephalopathy (HIE) shows
typical owl's eye abnormal
hyperintensity within the
central gray matter from
chronic spinal cord infarction.
(Right) Axial T1WI MR in case
of severe HIE shows focal low
signal within the central cord
due to old infarction with
myelomalacia.
• Spinal cord neoplasm
• Radiation myelopathy
PATHOLOGY
• Up to 50% of cases have no known etiology
• Majority of known causes relate to aortic pathology
• Septicemia; systemic hypotension
• Blunt trauma with dissection
• Fibrocartilaginous embolism
• Iatrogenic; transforaminal steroid injection, selective root
block
CLINICAL ISSUES
• Abrupt onset weakness, loss of sensation
• Rapid progression; maximum deficit within hours
• Poor prognosis, with permanent disabling sequelae
• Pain is frequent and disabling feature of cord infarct
• Treatment: Anticoagulation with heparin and aspirin;
steroids; supportive care and rehabilitative physical therapy
334
(Left) Sagittal T2 MR shows
slight hyperintensity in the
distal thoracic cord ſt in this
patient with acute onset of leg
weakness. There is a
geographic region of increased
signal in the superior
aspect of the thoracic
vertebral body due to
concomitant cord and
vertebral body infarcts. (Right)
Sagittal STIR MR shows the
cord hyperintensity involving
the mid and dorsal aspect of
the thoracic cord ſt along
with the vertebral body
infarction . The classic
anterior 2/3 of the cord
involved is not always present.
Subarachnoid Hemorrhage
KEY FACTS
Vascular Disorders
TERMINOLOGY
• Hemorrhage into spinal subarachnoid space from variety of
etiologies
○ Trauma (> 50%)
○ Aneurysmal subarachnoid hemorrhage (SAH) with spinal
extension
○ Spinal arteriovenous malformations
– Mainly types II, III, IVc, conus malformations
○ Tumor
○ Anticoagulant therapy
○ Infection (pneumococcal meningitis, herpes)
○ Systemic disease
○ Spinal artery aneurysm (rare)
IMAGING
• Fluid-fluid level within thecal sac
• Variable depending on stage of blood breakdown and
byproducts
• Dynamic enhanced MRA useful as screen for spinal vascular
malformation
TOP DIFFERENTIAL DIAGNOSES
• Epidural hemorrhage
• Subdural hemorrhage
• Intramedullary hemorrhage
PATHOLOGY
• Rare reports of cervical/thoracic arachnoiditis developing
following spinal SAH
CLINICAL ISSUES
• Acute back or radicular pain ± signs of cord compression
(numbness, weakness)
○ Spinal SAH characterized by sudden headache, acute
sciatic pain, xanthochromic CSF, meningeal irritation,
sensory deficit or paralysis
○ Massive spinal SAH may give acute cord compression,
paraplegia, fecal and urinary incontinence
(Left) Sagittal T1WI MR of
subarachnoid blood following
an epidural blood patch,
presumably related to an
incorrect needle position,
shows oblong focus of T1
hyperintensity within the
distal thecal sac at the L5-S1
level due to methemoglobin.
No epidural lesion is present.
(Right) Sagittal T2WI MR of
subarachnoid blood following
an epidural blood patch,
presumably related to an
incorrect needle position,
shows blood to be of low
signal ſt. Epidural space is
normal.
(Left) Axial T1WI MR of
subarachnoid blood following
an epidural blood patch shows
focus of T1 hyperintensity
within the distal thecal sac at
the L5-S1 level ſt. (Right)
Sagittal T2 MR shows the
appearance of a large
subarachnoid hemorrhage,
which is layered within the
thecal sac with a well-defined
fluid-fluid level ſt.
335
Spontaneous Epidural Hematoma
KEY FACTS
TERMINOLOGY
• Hemorrhage build-up between dura and spine not caused
by significant trauma or iatrogenic procedures
IMAGING
• Extradural multisegmental T1 hyperintense fluid collection
Vascular Disorders
• Lentiform or biconvex
• T1WI acute: < 48 hours
○ Isointense > hypo-/hyperintense
• T1WI subacute and chronic
○ Hyperintense > isointense
• T2WI variably hyperintense
TOP DIFFERENTIAL DIAGNOSES
• Epidural metastasis
• Lymphoma
• Disc extrusion, migration
• Epidural abscess
• Subdural hematoma
(Left) Sagittal T1WI MR shows
an indistinct margin of the
cervical cord due to an
isointense mass within the
dorsal epidural space . The
location of the mass is best
identified at the inferior
margin as extradural .
(Right) Sagittal T2WI MR
shows a slightly
heterogeneous, long segment
hyperintense mass ſt within
the posterior epidural space
spanning the C2-T4 level. The
cord is severely compressed
and displaced anteriorly .
PATHOLOGY
• Idiopathic: 40-50%
• Minor trauma
• Anticoagulation
• Coagulopathy
• Disc herniation
• Vascular anomaly
CLINICAL ISSUES
• Acute onset of neck, back pain, paraparesis, bowel or
bladder dysfunction
• Severity and duration of neurologic deficit predictive of
postoperative neurologic recovery
○ Return to neurologic baseline after surgery
– 89-95% of patients with incomplete neurologic deficit
vs. 38-45% of patients with complete impairment
○ Improved outcome when surgery performed ≤ 36 hours
in patients with complete sensorimotor loss
– ≤ 48 hours in patients with incomplete deficit
336
(Left) Sagittal NECT with a
soft tissue window shows an
extensive epidural hematoma
as slightly increased
attenuation in the posterior
canal with displacement of the
cord anteriorly . (Right)
Sagittal T2WI MR shows a
larger cephalad extradural
mass ſt, which is mixed isoand hypointense, displacing
ventrally the cord and filum. A
smaller caudal epidural
hemorrhage shows mild
effacement of the thecal sac
at the L3-L4 level .
Subdural Hematoma
KEY FACTS
Vascular Disorders
TERMINOLOGY
• Accumulation of blood between dura, arachnoid
IMAGING
• Intradural collection hyperintense on T1WI, predominantly
hypointense on T2WI or gradient-echo imaging
• Thoracolumbar > lumbar or lumbosacral > cervical
• Clumped, loculated masses of hemorrhagic
density/intensity
TOP DIFFERENTIAL DIAGNOSES
• Epidural hematoma
• Subdural abscess
• CSF leakage syndrome
• Spinal meningitis
• Idiopathic hypertrophic spinal pachymeningitis
PATHOLOGY
• Trauma
• Bleeding diathesis: 54% of reported cases
• Iatrogenic cause is factor in 2/3 of those with abnormal
coagulation parameters
• Neoplasm
• Arteriovenous malformation
• Postoperative complication
• Spontaneous: 15%
CLINICAL ISSUES
• Acute onset of neck or back pain
• Radicular pain, bladder/bowel dysfunction
• Much less common than spinal epidural hematoma
• Treatment
○ May resolve spontaneously
○ Decompressive laminectomy with clot evacuation
– Indicated by severe and progressive deterioration of
neurologic symptoms
(Left) Sagittal T1WI MR
without fat saturation shows
prominent hyperintense linear
collections both ventral ſt
and dorsal within the bony
spinal canal with narrowing of
the thecal CSF space. (Right)
Sagittal T1WI MR with fat
saturation shows hyperintense
linear subdural blood
collections both ventral and
dorsal within the bony canal
with marked narrowing of
thecal CSF space. Iatrogenic
cause is a factor in 2/3 of
those with abnormal
coagulation parameters.
(Left) Axial T1WI FS MR shows
the typical appearance of
subdural hemorrhage with the
well-defined outer margin
bounded by the dura and an
inner lobulated margin giving
a Mercedes Benz sign. (Right)
Sagittal T1WI MR in a patient
with chronic neck pain
demonstrates diffuse ventral
and dorsal intraspinal
hyperintense collections with
intracranial extension.
337
Bow Hunter Syndrome
KEY FACTS
TERMINOLOGY
• Bow hunter stroke, positional occlusion of vertebral artery,
rotational occlusion of vertebral artery
• Vertebrobasilar insufficiency secondary to mechanical
occlusion or stenosis of vertebral artery during head
Vascular Disorders
rotation
IMAGING
• Occlusion or stenosis of vessel with head positional
dependence based on ultrasound, MRA, CTA, or catheter
angiography
• Along course of vertebral artery, typically at C1-C2 junction
PATHOLOGY
• Vertebral artery at C1-C2 particularly prone to mechanical
compression
• May occur anywhere along vertebral course related to
spondylosis, atlantoaxial instability, hypertrophy of
atlantooccipital membranes, paravertebral muscle fascial
bands
(Left) Coronal oblique CTA
shows focal extrinsic
narrowing of the left vertebral
artery at the C3-C4 level due
to facet degenerative
hypertrophy and osteophyte
formation . (Right) Lateral
catheter angiography in a
neutral position shows
moderate focal stenosis at the
C3-C4 level due to osteophytic
compression .
CLINICAL ISSUES
• Vertebrobasilar insufficiency
○ Motor or sensory deficits, ataxia, diplopia, dysarthria,
dysmetria, vertigo, visual field deficit, cranial nerve
dysfunction, syncope
• Treatment
○ Brace to restrict head motion, surgical fusion to prevent
atlantoaxial rotation, vertebral artery decompression
○ Vertebral artery stenting
DIAGNOSTIC CHECKLIST
• Temporary positional occlusion of 1 vertebral artery during
course of daily activities may be normal if asymptomatic
• Hypoplasia or stenosis of contralateral vertebral artery
predisposes patients to vertebrobasilar ischemic attacks
during head rotation
338
(Left) Anteroposterior
catheter angiography with the
head turned to the right
(asymptomatic head turn side)
shows a patent left vertebral
with mild C3-C4 level
narrowing . (Right)
Anteroposterior catheter
angiography with the head
turned to the left
(symptomatic head turn side)
shows occlusion of the
vertebral artery at the level of
the osteophytic compression
.
Vertebral Dissection
KEY FACTS
Vascular Disorders
TERMINOLOGY
• Vertebral artery (VA) dissection
• Irregularity of VA contour from intimal tear or
subadventitial hematoma
IMAGING
• Stenoocclusive dissection
○ Dissection to subintimal plane with vessel luminal
narrowing or occlusion
• Dissecting aneurysm
○ Dissection into subadventitial plane with dilatation of
outer wall
• Intramural hematoma is pathognomonic
○ Best seen as bright crescent on T1 fat-suppressed MR
• Conventional angiography is gold standard
TOP DIFFERENTIAL DIAGNOSES
• Extracranial atherosclerosis
• Fibromuscular dysplasia
• Miscellaneous vasculitis
• Congenital VA hypoplasia
PATHOLOGY
• Traumatic VA dissection
○ Direct or indirect arterial injury
• Spontaneous VA dissection
○ Many associations and predisposing factors
CLINICAL ISSUES
• Age: Adults < 45 years
DIAGNOSTIC CHECKLIST
• Check other vessels for 2nd dissection
• Look for suboccipital rind sign (hematoma without narrow
lumen)
• Cerebellar infarction in young to middle-aged adults; need
to exclude posterior inferior cerebellar artery infarction due
to VA dissection
(Left) Axial CECT in a patient
with idiopathic vertebral
artery dissection
demonstrates a normal caliber
of the left vertebral artery ſt
and a narrowed, eccentric
lumen of the right vertebral
artery . Note the normal
and symmetric foramina
transversarium. (Right) Axial
T1 FS MR in the same patient
reveals a hyperintense
crescent of a mural hematoma
with a small hypointense
patent lumen. Contralateral
vertebral artery shows no
methemoglobin hyperintensity
ſt. This is unilateral vertebral
artery dissection.
(Left) Axial CTA shows rim
enhancement of the left
vertebral artery st with a
low-density mural hematoma
and contrast filling the
narrowed lumen ſt. Subtle
linear lucency in the right
vertebral artery proved not to
be a dissection flap . (Right)
Axial T2 MR in a patient with
neck trauma and cervical
fractures reveals traumatic
vertebral artery dissection as
loss of right vertebral flow
void ſt, as compared to the
normal left side st. Note right
cervical hemicord
hyperintensity from cord
ischemia .
339