Brain-Neuroradiology Teaching Files
Transcript of Brain-Neuroradiology Teaching Files
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Neuroradiology Teaching Files
Department of radiology
Faculty of Medicine
Chiang Mai University
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Case 1
20-year-old woman with motorcycle accident
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Findings: axial NECT shows biconvex hyperdense extraaxial
mass at left temporal convexity with non-displaced linear
fracture of the overlying temporal bone. The left temporal lobe
is displaced medially with effacement of the ipsilateralsuparsellar cistern. The midbrain is shifted away from the
herniating temporal lobe.
Diagnosis: Skull fracture with left temporal epidural hematoma
(EDH) and left descending transtentorial herniation.
Discussion:• Acute hematoma is high density or high attenuation on CT.
Overlying skull fractures can often be visualized on bone
windows.
• Classic finding of EDH: well-defined biconvex or lentiform-
shaped hyperdense extraaxial mass.
• Associated fracture in 85-95% (with lacerated meningeal artery
or dural sinus)
• 95% supratentorial (most common in the temporal parietal
region)• Classic lucid interval develops in 50% of patient
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Frontal EDH
EDH exists in the potential space between the dura andthe inner table of the skull. EDH can cross the midline but
cannot cross cranial sutures where the dura is more firmlyattached.
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Extra-axial collections
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Case 2
25-year-old man with motorcycle accident
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Findings: axial NECT shows crescentic mixed hyper/hypodense
extraaxial mass at the left frontoparietal convexity. The left
cerebral gray-white matter interface is displaced medially. The
lateral ventricles are shifted to the right with mild dilatation of the right lateral ventricle secondary to foramen of Monro
obstruction.
Diagnosis: Left frontoparietal subdural hematoma (SDH) and
subfalcine herniation.
Discussion:• SDH exists between the dura and arachnoid due to stretching
and tearing of bridging cortical veins. SDH can cross sutures
but cannot cross dural attachment.
• Low density areas within the SDH could represent fresh
unclotted blood, serum extruded from the clot, or CSF fromarachnoid tear .
• A definite history of trauma may be lacking, particularly in
elderly patients.
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Brain herniation
1.Subfalcine herniation
2.Transtentorial herniation
- Descending (Uncal herniation)
- Ascending
3. Tonsillar herniation
4. External herniation
Brain herniation causes compression of brain, brain stem, nerves, and
blood vessels againts the rigid bony and dural margins
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First CT:
Left SDH with left-
to-right subfalcineand left descending
transtentorialherniation
FU CT 4 days
later: left PCA
infarction secondary
to ipsilateral
descendingtranstentorialherniation.
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Each examination demonstrates the brain at the time of the study.
No any imaging modality can substitute good clinical history andphysical examination.
Isodense acute EDH Post-op delayed SDH
CT of a head-injured patient whose clinical was notimproved after craniotomy to remove the left EDH.
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Case 3
A young man with motorcycle accident
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Findings: axial NECT shows multifocal, droplet-shaped, very low
density foci of air within the basal cisterns and right cerebellar fissures (subarachnoid space)
Diagnosis: Traumatic PneumocephalusDiscussion:
• skull base fracture with dural tear and direct communication
with air-containing paranasal sinus or mastoid air cells may
cause pneumocephalus.
• Pneumocephalus can occur in epidural, subdural,subarachnoid space, ventricles or brain parenchyma.
• Most cases of pneumocephalus resolve spontaneously within
days.
• CSF fistulae may occur in the patients presenting with
headache, rhinorrhea and recurrent meningitis. High resolutioncoronal CT, CT cisternography, Isotope tracers and MR
cisternography have been used to localize the fistula site.
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MR
Cisternography
shows CSF
Fistula (arrow)
in 2 cases with
posttraumatic CSFrhinorrhea
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Case 4
63-year-old patient with hypertension and left hemiparesis
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Findings: axial NECT shows a hyperdense mass at right thalamusand deep white matter with extension into the right lateralventricle.
Diagnosis: Acute hypertensive intraparenchymal hemorrhage with
accompanying intraventricular hemorrhage (IVH).Discussion:
• Hypertension is the most common cause of nontraumaticintraparenchymal hemorrhage in elderly patients. Theycommonly occur in the basal ganglia, thalamus, and pons.
• Hemorrhage into the posterior fossa with mass effect or extension into the ventricular system is associated with poor prognosis.
• Vascular malformations (AVM, cavernous angioma) are morecommon causes of hemorrhage in the younger patients.
• Hemorrhagic brain tumors are more complex, heterogenouswith associated edema. They usually has nonhemorrhagicareas that enhance after contrast administration.
• Other causes of nontraumatic intraparenchymal hemorrhageinclude amyloid angiopathy, hemorrhagic transformation of infarction, coagulopathy, venous infarction etc.
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Hypertensive hemorrhage
Basal ganglia Thalamus Pons
Criteria for Dx of hypertensive hemorrhage:
1. HT 2. Age > 45 y
3. Common location: BG(60%), thalamus,
pons, cerebellum
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Case 5
A patient with sudden onset of headache and alteration of
consciousness
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Findings: axial NECT shows diffuse high attenuation or high densitywithin the basal cisterns, Sylvain fissures and cortical sulci. Smallfocal hyperdense hematoma is seen at the left inferior frontallobe. Small amount of hyperdense IVH is also present in occipitalhorns with dilatation of temporal horns from hydrocephalus.
Diagnosis: Diffuse subarachnoid hemorrhage (SAH) with smallintraparenchymal hematoma, small amount of IVH andhydrocephalus.
Discussion:
• SAH exists in CSF space between the arachnoid and pia. SAH
extends into the cisterns and sulci, while SDH does not extendinto the sulci.
• The most common cause of nontraumatic SAH is rupture of intracranial aneurysm. Focal SAH or ICH are helpful in localizingthe bleeding source.
• 90 % of SAH is cleared from the CSF within 1 week. It is difficultto detect SAH on CT if it is a low hematocrit and a delay inscanning. A lumbar puncture revealing red blood cells or xanthochromia may confirm a suspected SAH.
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Investigation guideline for patient withsuspected rupture intracranial aneurysm
Plain CT brain
Clinically suspected SAH
(-)
LP
(+)
CTA and/or DSAor MRA
(-)
Repeat DSA 2 weeks
(+)
Treatment(+)
(+)
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SAH (Ruptured ACoA Aneurysm)
NECT DSA
Focal SAH or ICH are helpful in localizing the bleeding source as in thiscase, localized SAH in the anterior interhemispheric fissure due to rupture ACoA aneurysm.
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CTA:sagittal MPR
CTA:3D color VR
DSA: lateral view
DSA: frontal view
Aneurysm at the right MCA bifurcation in a 46-year-old woman with sudden headache
and previous CT showed SAH at the suprasellar cistern and the right sylvian fissure.
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Case 6
A man presented with right hemiparesis 6 hours PTA
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Findings: axial NECT shows a linear hyperdensitywithin the left MCA and hypodensity with loss of G-Wdifferentiation of the left insular cortex and left basal
ganglia.Diagnosis: hyperacute left MCA infarction
Discussion:
• The CT findings in acute cerebral infarction evolvewith time.
• CT scans can detect early signs of MCA infarctionwithin 6 hours in up to 82% of patients.
• Early signs of MCA infarction include a hyperdenseacute intraluminal thrombus in the MCA (hyperdense
MCA sign), obscuration of the lentiform nucleus, andloss of gray-white interface of the insular cortex(insular ribbon sign).
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Early sign of MCA Infarct
Hyperdense MCA sign Insular ribbon sign and
obscuration of the lentiform nucleus
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Threshold of ischemia
CBF
50-60 ml/100 gm/min normal
15-20 ” Neurological
dysfunction
<10 ” infarction
Ischemicpenumbra
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CBF in ml/g/min
Regions of decreased CBF can be quantified to three zones:
1. central core with irreversible damage
2. salvageable penumbra (tissue at risk)
3. oligemic penumbra (low flow without risk of cell death)
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Stroke onset
Early detection of ischemia
Thrombolytic Rx (iv rtPA)
risk of hemorrhage
(5.2%)
Salvage ischemic brain
3 hrs
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Goals of acute stroke imaging “4P”
• Parenchyma: Assess early signs of acute stroke,
R/O hemorrhage or other lesions (tumor, infection)
• Pipes: Assess extra- and intra-cranial circulation for evidence of intravascular thrombus
• Perfusion: Assess CBV, CBF, MTT(TTP)
• Penumbra: Assess tissue at risk of dying if ischemiacontinues without recanalization of intravascular thrombus
Ref: Rowley. AJNR 2001;22:509-601
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Acute stroke imaging “4P”
• Parenchyma:
NECT: to exclude hemorrhage, other lesions
large area of infarct(>1/3 of MCA territory)
DWI: detect hyperacute infarction
• Pipes: CTA, MRA
• Perfusion: CTP, MR-PWI
• Penumbra: Perfusion CT (CBV/CBF mismatch)
Perfusion MR (Diffusion/perfusion mismatch)
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Patients with ischemic stroke who could be treated with rtPA
• Onset of symptoms < 3 hours before Rx
• No head trauma or prior stroke in previous 3 months
• No myocardial infarction in previous 3 months
• No GI or urinary tract hemorrhage in previous 21 days
• No major surgery in the previous 14 days
• No history of previous intracranial hemorrhage
• BP: systolic <185, diastolic < 110
• No seizure with postictal residual neurological
impairment….
Ref: AHA/ASA Scientific statement.
Acute stroke imaging protocol
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Acute stroke imaging protocol
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Stroke fast track
Plain CT brain within 3 hours
Indication for thrombolytic Rx (IV rt-PA)
Normal CT or early sign infarction
Contraindication to thrombolytic Rx:
hemorrhage
large area of infarct (>1/3 of MCA territory)
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Acute MCA infarction
78 –year-old woman with sudden left hemiparesis 1 day PTA
NECT shows a hypodense area of large infarction involving
the right middle cerebral artery vascular territory.