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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_2603_Библиотеки_им_академика_М_И_Перельмана
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2.1 · Stroke (Brain Infarction)
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2
. Fig. 2.1.4 Axial brain CT illustration demonstrates
infarction within the vascular region of the middle cerebral
artery with multiple enhanced lines inside it representing luxury
perfusion
. Fig. 2.1.6 Axial brain CTA image of a patient with left brain
infarction shows blockage of the left middle cerebral artery (M1)
segment ( arrowhead )
. Fig. 2.1.5 Axial brain CT image shows acute lacunar
infarction in the right centrum semiovale with small ring of
cytotoxic edema around it ( arrowhead )
Signs on MRI and DWI
5 Hyperattenuated vessel sign : it is seen on T2*
images as hyperintense vessel (like on unenhanced
CT images).
5 T2* images : they are very sensitive to detect
hemorrhage and microhemorrhages. Hemorrhage
is seen as areas of abnormal blooming, while
hemosiderin is seen as areas of low signal
intensities.
5 DWI : areas of infarction are seen as areas of high
signal intensity due to water motion impedance
(cytotoxic edema), usually 30 min from the start of
the attack (. Fig. 2.1.7 ). On the ADC map, the
areas of high signal intensity on DWI show low
signal intensity. Chronic infarction shows low
signal intensity on DWI and high signal intensity
on ACD maps. The two must be assessed together
to diagnose chronic infarction. DWI is accurate in
detecting brain stem and lacunar infarctions.
5 MR spectroscopy in infarction shows high lactate
and low N -acetyl aspartate, choline, and creatine
(present up to 5 weeks postattack).
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Chapter 2 · Neurology
2.2 Stroke Diseases and Syndromes
Stroke can be a symptom rather than an actual disease. Some
2
systemic diseases present in the form of stroke. Other diseases or syndromes are associated with stroke as one of their
diagnostic criteria. Some syndromes or diseases arise due to
stroke in a certain area of the brain. is topic discusses some
of the known and uncommon causes, syndromes, and diseases of stroke.
Moyamoya Disease (Progressive Occlusive
Arteritis)
Moyamoya disease is characterized by a progressive occlusion of arteries of the circle of Willis due to intimal wall
thickening of the distal internal carotid artery and its proximal anterior cerebral artery branch bilaterally, with the formation of abnormal collateral networks that develop adjacent
to the stenotic vessel. ese collaterals give the shape of a pu
of smoke, which is called “moyamoya” in Japanese.
Moyamoya disease is a rare disease worldwide but with
. Fig. 2.1.7 Axial brain DWI shows acute lacunar infarction in
the left paraventricular area ( arrowhead )
Further Reading
de Lucas EM, etal. CT protocol for acute stroke: tips and
tricks for general radiologists. Radiographics.
2008;28:1673–87.
Johannsen L, et al. “Pusher syndrome” following cortical
lesions that spare the thalamus. J Neurol. 2006;253:
455–63.
Karnath H-O.Pusher syndrome– a frequent but little-known
disturbance of body orientation reception. J Neurol.
2007;254:414–24.
Mullins ME. e hyperdense cerebral artery sign on CT scan.
Semin Ultrasound CT MR. 2005;26:394–403.
Shetty SK, etal. CT perfusion in acute stroke. Neuroimaging
Clin N Am. 2005;15:481–501.
Srinivasan A, etal. State-of-the-art imaging of acute stroke.
RadioGraph. 2006;26:S75–95.
Vu D, et al. Non-contrast CT in acute stroke. Semin
Ultrasound CT MR. 2005;26:380–6.
high incidence in Japanese. Occlusion usually occurs in both
hemispheres, but unilateral occlusion can occur. e disease
can be seen in association with sickle cell disease and neuro bromatosis.
e disease peaks in the rst decade and dips in the
fourth decade. Patients present in young age with recurrent
strokes, headaches, and behavioral disturbance. e disease
can be suspected in a young adult presenting with stroke,
with no predisposing factors. Diagnosis is essentially established by angiography or MR angiography.
Signs on CT, MRI, and MR Angiography
5 Large network of collaterals in the basal ganglia
and brain stem fed by the internal carotid artery,
the basilar artery, and the anterior cerebral artery
giving the appearance of a puff of smoke
(pathognomonic) (. Fig. 2.2.1 ).
5 On T1W images, there are multiple hypointense,
flow void lesions located in the basal ganglia
representing the abnormal collateral networks
(. Fig. 2.2.2 ) .
2.2 · Stroke Diseases and Syndromes
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a
67
b
2
. Fig. 2.2.1 MR angiography of a patient with moyamoya disease ( a ) and MR angiography in a normal healthy patient ( b ) for
comparison. In ( a ), there is irregular arterial collateral formation in the region of the anterior cerebral arteries bilaterally in
fi gure ( a ) ( arrowheads ), with complete disappearance of the middle cerebral artery (MCA) (M1 segment). Compare the image in ( a ) with
the normal MRI appearance of the circle of Willis in ( b )
a
b
. Fig. 2.2.2 Axial T1W brain MR illustration ( a ) with axial FLAIR MRI ( b ) of a patient with moyamoya disease shows multiple fl ow void
signal intensities in the region of the basal ganglia bilaterally representing the abnormal collateral formation ( arrowheads ).
Leukoencephalopathy at the region of the posterior horns of the lateral ventricles ( b ) can be seen ( arrow ) aff ecting the right side more
than the left side
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Chapter 2 · Neurology
Cerebral Amyloid Angiopathy
Cerebral amyloid angiopathy (CAA) is a disease that occurs
2
due to deposition of a protein (AB peptide) or amyloid substance in the arteriolar wall of the cerebral vessels, causing
weakening and fragility of blood vessel walls. Later, intracerebral bleeding develops due to spontaneous blood vessel rupture.
In CAA, amyloid proteins replace the contractile element
of the arteriolar muscle layer, leading to increased fragility of
the walls. CAA is not a part of systemic amyloidosis, and it is
the most common cause of spontaneous, nontraumatic intracranial bleeding in nonhypertensive elderly patients.
CAA should be suspected when an elderly patient
(60years) presents with unexplained spontaneous intracranial bleeding that is lobar and located very super cial in the
cortex. It is responsible for up to 20 % of nontraumatic brain
hemorrhage and hemorrhagic infarction and up to 30 % of
lobar bleeding.
CAA can be associated with Alzheimer’s disease, with
dementia occurring in up to 40 % of cases. Dementia in CAA
patients occurs and progresses much faster than dementia in
patients with Alzheimer’s disease. Diagnosis of CAA is usually done by clinical history and the radiological features of
the CT or the MRI.
Signs on CT and MRI
5 Acute intracranial bleeding area (lobar
hemorrhage) is seen as high-density area on CT
images or with high T1/T2 signal intensities on MRI
that is located in the superficial cortex and the
subcortical white matter (. Figs. 2.2.3 and 2.2.4 ),
with a distribution different from those resulting
from hypertensive bleeding (usually deep within
the brain). Bleeding due to CAA is characteristically
multiple, spares the basal ganglia and brain stem,
and is located at the corticomedullary junction.
5 On MRI, multiple chronic microhemorrhages are
seen as signal void, a few millimeters in size
hypointense lesions in the deep white and the
subcortical white matter on T2* images
(. Fig. 2.2.3 ).
5 CAA affects commonly the frontal and the parietal
lobes. Up to 10–50 % of cases bleed in more than
one lobe.
. Fig. 2.2.3 Axial T1W brain MR illustration demonstrates
cerebral amyloid angiopathy (CAA). There is corticomedullary
bleeding in the left parieto-occipital area surrounded by
cytotoxic edema ( arrowhead ). Multiple areas of hypointense
signal intensities scattered within the white matter representing
chronic microhemorrhages. An area of low signal intensity is seen
in the right parieto-occipital area representing gliosis ( arrow )
. Fig. 2.2.4 Axial brain nonenhanced CT in a patient with
intracranial bleeding due to CAA shows an area of bleeding in the
right temporo-occipital region involving the cortices and the
corticomedullary junction with a rim of cytotoxic edema
( arrowhead )
2.2 · Stroke Diseases and Syndromes
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CADASIL (Cerebral Autosomal Dominant
Arteriopathy with Subcortical Infarcts
and Leukodystrophy)
CADASIL is the most common form of familial strokes with
progressive dementia due to vasculopathy of the deep perforating arteries of the cerebral white matter. Patient with
CADASIL presents with multiple attacks of strokes beginning usually between 40 and 60 years of life. Patients typically
have no risk factors for stroke. Psychiatric symptoms occur in
30 % of cases (e.g., depression).
Diagnostic Criteria for CADASIL
5 Young age (<50years)
5 Two of the following clinical ndings: stroke-like episodes
with permanent neurological defects, migrainous headache,
major mood disturbance, or subcortical dementia
a
5 No risk factors for stroke
5 Positive family history for such stroke attacks
5 On MRI, white matter changes without cortical infarcts
Signs on MRI
5 Extensive white matter lesions and basal ganglia
abnormalities in the absence of cortical infarcts
typically seen in the temporal lobes and the
extreme and external capsule (. Fig. 2.2.5 ). The
lesions do not enhance after contrast injection.
5 Widening of the periventricular spaces
( Virchow–Robin spaces ) (. Fig. 2.2.6 ).
5 MR angiography is typically normal (no vascular
lesion).
b
. Fig. 2.2.5 Axial nonenhanced brain CT ( a ) and axial FLAIR MRI ( b ) of a patient with cerebral autosomal dominant arteriopathy with
subcortical infarcts and leukodystrophy (CADASIL) show bilateral diff use white matter lesions with aff ection of the right external capsule
( arrowheads ). Pineal calcifi cation can be seen as a secondary fi nding ( arrow )
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Chapter 2 · Neurology
a
b
2
. Fig. 2.2.6 Axial T1W ( a ) and FLAIR ( b ) brain MRI of another patient with CADASIL shows bilateral diff use white matter lesions
(leukoencephalopathy) with dilated right Virchow–Robin space ( arrowhead )
MELAS (Mitochondrial Myopathy,
Encephalopathy, Lactic Acidosis,
and Stroke-Like Episodes)
MELAS is a mitochondrial disease characterized by episodes
of infarction-like cerebral injuries causing hemiparesis or
hemiplegia, hearing loss, or cortical blindness. e disease is
characterized by elevated serum levels of lactic acid (lactic
acidosis).
MELAS starts during early infancy or between the ages of
2 and 5 years. e child presents with vomiting, seizures, failure to thrive, and infarction-like injuries that can occur anywhere in the brain. Interestingly, angiography reveals no
Signs on CT and MRI
5 There are hypodense, asymmetric areas on CT
located mainly in the occipitotemporal areas
representing infarction that does not follow a
vascular territory (. Fig. 2.2.7 ). The same area
shows low T1/high T2 signal intensities. Diffuse
brain atrophy can be seen.
5 On CT, bilateral basal ganglia calcification may be
seen due to old infarctions (. Fig. 2.2.7 ).
5 MR angiography is typically normal (excluding
vasculitis or moyamoya).
5 High lactic acidosis peak in MR spectroscopy.
vascular occlusion or vascular disease. e infarction-like
episodes are due to abnormal physiology rather than abnormal anatomy or vascular occlusion.
2.2 · Stroke Diseases and Syndromes
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a
71
b
2
. Fig. 2.2.7 Axial nonenhanced brain CT illustration ( a ) and image ( b ) of a patient with mitochondrial myopathy, encephalopathy, lactic
acidosis, and stroke-like episodes (MELAS) demonstrate the radiological features of MELAS. In ( a ), there is a hypodense lesion in the right
temporoparietal region that does not follow a vascular territory ( arrows ) with bilateral basal ganglia calcifi cations, as typical signs of MELAS. In
( b ), a young patient diagnosed with MELAS shows hypodense lesions in the right temporal area representing infarction ( arrowhead )
Cortical Laminar Necrosis
virus infection). Chicken pox encephalitis can lead to the
development of Reye’s syndrome among other cerebral
Cortical laminar necrosis (CLN) is a disease characterized by
complications.
destruction of di erent layers of the cerebral cortex, most
prominently the third cortical layer.
On histopathological examination, CLN shows brain
infarction of the cortical neuronal elements and the blood
vessels (pan-necrosis) without hemorrhage or calci cation. CLN has been reported in patients with Reye’s syndrome.
Reye’s syndrome is a rare condition characterized by acute
nonin ammatory encephalopathy and fatty degeneration of
the viscera, commonly the liver. It commonly a ects children
between 2 months and 15 years of age. e classical clinical
presentation is a child presenting with vomiting, headache,
convulsions, and signs of encephalopathy, associated with
hepatic dysfunction and elevated liver enzymes. Liver biopsy
classically shows fatty in ltration. A liver biopsy can help to
rule out other conditions that may be a ecting the liver and
causing liver dysfunction.
e explanation of Reye’s syndrome pathology is linked
to hepatic and neuronal mitochondrial dysfunction triggered
by certain toxins or infections. e most common causes of
Reye’s syndrome are reaction to salicylate (aspirin) or infec-
Signs on MRI
5 Typically, CLN lesions show hyperintense curvilinear
lines along the cortical gyri and convolutions on both
T1W and FLAIR images (. Fig. 2.2.8 ), usually seen
from 1 month to 1 year after the ischemic event.
5 CLN lesions show contrast enhancement after
contrast injection, classically 2 weeks after the
initial attack.
5 In Reye’s syndrome, the brain shows diff use or focal
ischemia in a laminar pattern similar to CLN. Multiple
abnormal white matter lesions with heterogeneous
signal intensities may be found refl ecting diff erent
stages of Wallerian degeneration. The latter fi nding
is commonly seen in chronic stage of the disease.
Wallerian degeneration is a type of neurological
degeneration that is seen after an axonal injury. The
distal and the proximal segments of the damaged
axon with its myelin are fragmented until the fi rst
node of Ranvier.
tions like in uenza B and chicken pox (varicella-zoster
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Chapter 2 · Neurology
a
b
2
. Fig. 2.2.8 Axial T1W ( a ) and T2W ( b ) brain MRI in a 7-year-old child with chicken pox encephalitis shows cortical laminar necrosis
(CLN). Notice the curvilinear hyperintense signal intensity lines that follow the convolutions of the gyri on both hemispheres ( arrowheads ),
with diff use white matter lesions seen on T2W images
Man-in-the-Barrel Syndrome
Man-in-the-barrel syndrome (MIBS) is a rare disease characterized by paralysis of both arms while the cranial nerves and
motor functions of the legs are functioning, giving the patient
appearance of a man being con ned to a barrel.
MIBS is caused by bilateral ischemia or infarction involving the border-zone areas between the anterior cerebral
artery and the middle cerebral artery (MCA) (watershed
zones) at the level of the motor cortex of the arm. Spinal cord
disease paralyzing both brachial plexus can cause this disease, but it is extremely rare.
e most common cause of MIBS is systemic hypotension following cardiac surgeries or cardiac arrest. MIBS association with pontine myelinolysis, head trauma, and cerebral
metastasis has been reported.
Signs on CT and MRI
5 CT can be normal.
5 MRI typically shows bilateral low T1 and high T2
signal intensities in the parietotemporal,
sensorimotor cortical areas of the arm and hand in
the brain (. Fig. 2.2.9 ) .
. Fig. 2.2.9 Axial brain FLAIR MR illustration shows the
radiological fi ndings in patients with man-in-the-barrel
syndrome (MIBS)
2.2 · Stroke Diseases and Syndromes
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Locked-In Syndrome
Locked-in syndrome (LIS) is a rare disease characterized by
normal wakefulness and cognition, anarthria, quadriplegia,
and gaze paralysis, caused by ventral pontine infarction.
Patients with LIS are fully conscious, yet they experience
almost complete motor paralysis. Typically, patients are able
to communicate via vertical gaze movement and blinking.
LIS is classically caused by infarction or hemorrhage involving the pontine perforating arteries arising from the basilar
artery. Other causes of LIS include Guillain–Barré syndrome,
West Nile encephalitis, and amyotrophic lateral sclerosis.
Signs on CT and MRI
Brain scan typically shows infarction or hemorrhage
involving the ventral pontine region or the cerebral
peduncles.
Brain Stem Infarction Syndromes
e brain stem holds nuclei of the cranial nerves. e midbrain contains the nuclei of the cranial nerves 3 and 4. e
pons contains the nuclei of the cranial nerves 5–8, and the
medulla contains the nuclei of the cranial nerves 9–12.
Infarction within the brain stem can result in cranial nerve
palsies among other complications. Di erent syndromes may
arise according to the infarcted region within the brain stem.
A summary of the most common disorders arising due to
brain stem infarction is presented below:
5 Millard–Gubler syndrome : unilateral hemiplegia or
hemiparesis with contralateral lower motor neuron facial
(CN 7) paralysis due to hemorrhage, tumor, or infarction
of the pons.
5 Claude syndrome : unilateral oculomotor (CN 3) nerve
palsy with contralateral hemiataxia due to paramedial
midbrain infarction (. Fig. 2.2.10 ).
5 Benedikt syndrome : unilateral oculomotor (CN 3) nerve
palsy with contralateral limb tremor or paralysis. It can
be caused by pontine infarction due to posterior cerebral
artery occlusion.
5 Weber syndrome : unilateral oculomotor (CN 3) nerve palsy
with contralateral hemiplegia due to midbrain infarction.
5 Avellis syndrome : hemiparalysis of the larynx and so
palate on the same side due to infarction of the nucleus
ambiguous in the medulla oblongata (central) or a mass
lesion around the jugular foramen (peripheral) involves
the glossopharyngeal and the vagus nerves (CN 9 + 10)
(. Fig. 2.2.11 ).
5 Foix–Chavany–Marie syndrome : pseudobulbar palsy (CN
9–12) due to bilateral cortical infarction in the territory
of the MCA.
5 Babinski–Nageotte syndrome : ipsilateral Horner’s
syndrome; facial loss of pain and temperature; cerebellar
. Fig. 2.2.10 Axial T1W brain stem MR illustration at the level of the
pone demonstrates the typical infarction region causing Claude
syndrome ( arrowhead )
hemiataxia, with paresis of the larynx and pharynx; and
contralateral hemiparesis and loss of pain and
temperature. e disease arises due to unilateral
infarction of the medulla oblongata involving the
spinal trigeminal tract and nucleus, nucleus ambiguous,
lateral spinothalamic tract, sympathetic bers,
corticospinal tract, and a erent spinocerebellar tract
. Fig. 2.2.11 ).
(
5 Cestan–Chenais syndrome : has same clinical
presentation as Babinski–Nageotte syndrome and
arises due to unilateral infarction of the medulla
oblongata involving the spinal trigeminal tract and
nucleus, nucleus ambiguous, lateral spinothalamic
tract, sympathetic bers, and corticospinal tract
(. Fig. 2.2.11 ).
5 Lateral medullary (Wallenberg) syndrome : ipsilateral
Horner’s syndrome; facial loss of pain and
temperature; cerebellar hemiataxia, with paresis of the
larynx and pharynx; and contralateral loss of body pain
and temperature. It arises due to unilateral infarction of
the medulla oblongata involving the spinal trigeminal
tract and nucleus, nucleus ambiguous, lateral
spinothalamic tract, sympathetic bers, a erent
spinocerebellar tracts, and vestibular nuclei (
and 2.2.12 ).
5 Dejerine syndrome : ipsilateral tongue weakness with
contralateral hemiparesis and face sparing
hemihypesthesia. It arises due to unilateral infarction of
the medulla oblongata involving the hypoglossal nucleus
or bers, corticospinal tract, and spinal medial lemniscus
(. Fig. 2.2.11 ).
5 Reinhold (hemimedullary) syndrome : ipsilateral Horner’s
syndrome; facial loss of pain and temperature; cerebellar
. Figs. 2.2.11
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Chapter 2 · Neurology
hemiataxia, with paresis of the larynx and pharynx; and
contralateral hemiparesis and face sparing
hemihypesthesia. It arises due to unilateral infarction of
2
the medulla oblongata involving the spinal trigeminal
a
c
tract and nucleus, nucleus ambiguous, a erent
spinocerebellar tracts, sympathetic bers, hypoglossal
nucleus or bers, corticospinal tract, and spinal medial
lemniscus (. Fig. 2.2.11 ) .
b
d
e
. Fig. 2.2.11 Axial T1W brain stem MR illustration at the level of the medulla demonstrates diff erent kinds of diseases according to the area of
medullary infarction: ( a ) Avellis syndrome, ( b ) Cestan–Chenais syndrome, ( c ) Reinhold (hemimedullary) syndrome, ( d ) Babinski–Nageotte
syndrome, ( e ) Wallenberg syndrome, and ( f ) Dejerine syndrome
f
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