Neuroimaging Resident

8/6/2019 Neuroimaging Resident

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Plain film of skull


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Normal sella turcica

Posterior clinoidAnterior clinoid

Dorsum sellae

Floor of sella


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ICP

loss of dorsum sella sign


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Pituitary tumor

Double floor sign


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Large intrasella mass

2

3

1

ballooning of

sella


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Anatomy


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MedullaInferior

CerebellarPedancle


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Basillar a.

Pons

Forth ventricle

Temporallobe


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Pons

PituitaryFossa

Forth ventricle


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Midbrain

Gyrus rectus of frontal lobe

MCA

Medial

temporal

Amygdala


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PosteriorLimb of int. capsule

Occipital lobe

Caudate

Ant limb of

Int. capsule

Putamen

Sylvian fissure

Thalamus


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Lateral ventricle

Splenium


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Frontal lobe

Parietal lobe

Central sulcus


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CT brain


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Computed tomography (CT)scan

Cross-sectional representation ofanatomy created by a computer-generated analysis of the attenuation

of x-ray beams passed through asection of the body


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CT scan: indication

Primary study of choice inEvaluation of acute trauma to the brainand spine

Subarachnoid hemorrhage,

CT is complementary to MR in theevaluation of the skull base, orbit, andosseous structures of the spine.


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CT scan

Intravenous contrast is oftenadministered prior to or during a CTstudy to

identify vascular structures detect defects in the blood-brain

barrier (BBB), which are associated withdisorders such as tumors, infarcts, and

infections.

Carried risk for allergic reaction,nephrotoxicity


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CT scan

Advantage

Availability

Shorter scan time

Detection of hemorrhage Disadvantage

Contrast media

Artifacts in posterior fossa or area surrounded by

bone Radiation exposure is between 3 and 5 cGy per

study


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CT brain check list

CT brain with/without contrast

Soft tissue, bony structure, sinus, orbit,mastoid

Meninges, CSF space surrounding brain

Brain parenchyma Abnormal hyper/hypodensity lesion+location

Abnormal calcification +location

Grey-white differentiation +location

Edema Location

Pressure effects on ventricle

Midline shift

herniation


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CT brain check list

Ventricles Any pressure effect on ventricles from edema

Abnormal dilatation of ventricle

Contrast enhancement Location

Pattern: nodular, gyral, ring, homogeneous,inhomogeneous

Others Abnormal vascular structure

Hyperdense MCA

Empty delta sign

Pituitary, pineal


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CT brain check list

Diagnosis Diagnosis

Location and SIDE!!!

Stage: acute, subacute, chronic (ifindicated)

Other important findings: eg. Withherniation


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MRI


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Magnetic resonance imaging (MRI

Complex interaction between hydrogenprotons in biologic tissues, a staticmagnetic field (the magnet), and

energy in the form of radiofrequency(Rf) waves of a specific frequencyintroduced by coils placed next to the

body part of interest


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MRI

Advantage Better resolution esp. temporal lobe,

posterior fossa, spinal cord MRA/MRV

Special techniques: DWI Disadvantage Availability

Longer scan time Interpretation of hemorrhage


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MRI of the brain


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MRI of the brain

MRS


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Use ofMRI in emergency

situation

Very early case of ischemic stroke

Cerebral venous sinus thrombosis

Acute spinal cord compression


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Contraindication forMRIscan Cardiac pacemaker or permanent pacemaker

leads

Internal defibrillatory device Cochlear prostheses

Bone growth stimulators

Spinal cord stimulators

Electronic infusion devices

Intracranial aneurysm clips (some but not all)

Ocular implants (some) or ocular metallic foreignbody

McGee stapedectomy piston prosthesis

Omniphase penile implant Swan-Ganz catheter

Magnetic stoma plugs

Magnetic dental implants

Magnetic sphincters

Ferromagnetic IVC filters, coils, stentssafe 6


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MRI

T1W T2W

CSF Grey matterWhite matter

CSF

Grey matterWhite matterLesion, edem


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FLAIR (fluid attenuated inversion recovery)

CSF Grey matterWhite matter

Lesion, edema


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Case 1

57 year old woman presented to theER with sudden onset lefthemiparesis 2 hours before arriving

at the ER


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Answer


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CT brain check list

CT brain with/without contrast

Soft tissue, bony structure, sinus, orbit,mastoid

Meninges, CSF space surrounding brain

Brain parenchyma Abnormal hyper/hypodensity lesion+location

Abnormal calcification +location

Grey-white differentiation +location

Edema Location

Pressure effects on ventricle

Midline shift

herniation


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CT brain check list

Ventricles Any pressure effect on ventricles from edema

Abnormal dilatation of ventricle

Contrast enhancement Location

Pattern: nodular, gyral, ring, homogeneous,inhomogeneous

Others Abnormal vascular structure

Hyperdense MCA

Empty delta sign

Pituitary, pineal


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Description

CT brain without contrast Soft tissue, bony structure, sinus, orbit,

mastoid- normal

Hypodensity lesion in the rightfrontoparietal region

Loss of gray white differentiation/ loss ofsulci in the right frontoparietal region

Edema in the right frontoparietal region withpressure effect on right lateral ventricle

No midline shift


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CT brain check list

Diagnosis Diagnosis

Location and SIDE!!!

Stage: acute, subacute, chronic (ifindicated)

Other important findings: eg. Withherniation


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Diagnosis

Acute right middle cerebral arteryinfarction


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Left hyperdensed

MCA sign


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Anterior choroidal a.

Posterior cerebral a.


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Case 2

40 years old man

Was sent to ER due to confusion


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Answer


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Lensshapeextra-axiallesion

Softtissueswelling


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DescriptionCT brain without contrast

Soft tissue swelling at the rightfrontal region

Normal orbit and bony structuresLens-shape, extra-axial hyperdensitylesion overlying the right frontal lobe

Some pressure effect to the adjacentbrain and ventricles

No midline shift


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DiagnosisAcute epidural (or Extradural)haematoma at right frontal lobe


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Case 3

50 years old man

Was sent to ER due to confusion


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Answer


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Extra-axiallesion

withpressure

effect


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Normal orbit, sinus and bonystructure

Isodensity, extra-axial, concave

lesion overlying left fronto-parietalarea

With midline shift to the left

With pressure effect on the adjacentbrain and obliteration of the leftlateral ventricle


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DiagnosisSubacute subdural haematoma atleft fronto-parietal area withmidline shift


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Epidural haematomaLucid interval

Associated fracture

laceration of middle meningealartery

Dont cross suture

Epidural VS Subdural

haematoma

1=84.22HU

EDH: typical lens shaped, 60-90HU


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EDHcross midline (1)

Braincontusion (2)

2

11



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haematoma

Subduralhaematoma

generally more

largerCollection betweendura and arachnoid

Venous bleeding

May cross suturebut dont crossmidline


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Acute SDH: hyperdense


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IsodenseSDHSubacuteSubdural

haematoma


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Subacute SDH: isodense, +C needed


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Chronic SDH: hypodensity=CSF


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Case 4

50 years old womanWas found unconscious and sent toER


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Answer


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HyperdensityinSubarachnoidspace


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Description

CT brain without contrastNormal skull, orbit and paranasalsinuses

Hyperdensity lesion in the

subarachnoid space especially at leftsylvian fissure and basal cistern

Mild dilatation of the ventricularsystem

No midline shift

No clear abnormal hypodensity inthe brain parenchyma


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DiagnosisAcute subarachnoid haemorrhage


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CauseTraumatic

Aneurysmal bleeding

AVM

Extension from intraparenchymalbleed

UnknownPerimesencephalic cisterns(excellent outcome, negativeangiogram)

Subarachnoid haemorrhage

Subarachnoid


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Subarachnoid

haemorrhage

Non-contrast CT!!!


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Axial CT brain : before contrastinjection!!

C 5


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Case 5

50 years old man

Was found comatose and sent toER


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Answer


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Hyperdensitylesionin middleofpons

D i i


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Normal skull, orbit and paranasalsinuses

Hyperdensity lesion occupying middle

of pons with some local pressureeffect

Some hyperdensity lesion surroundingthe brainstem (subarachnoid blood)

(Normal ventricular size)

DiagnosisAcute pontine haemorrhage

Common sites of hypertensive


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Co o s tes o ype te s e

hemorrhage

Basal ganglia

Thalamus

Cerebellar

Pons

H d bl di MRI


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How do see bleeding on MRI

Depends on timing after hemorrhage


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Bleeding on MRI


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Bleeding on MRI

Biochem Stage Time T1W T2W

OxyHb in

RBCs

Hyperacute Hours Iso

DeoxyHb

in RBCs

Acute Hrs to

days

Iso,

MetHb in

RBCs

Early

subacute

Days

Extracell

MetHb

Subacute

to chronic

Days to

months

Ferritin

Hemoside

rin

Remote Days to

indefinite

Iso,

Hyperacute hematoma


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Hyperacute hematoma

T1W T2W

Acute hematoma


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Acute hematoma

T1W T2WProton

density

Early subacute hematoma


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Early subacute hematoma

CT T1W T2W


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Case 6


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Case 6

27 years old woman

30 weeks pregnant

Presented with headache andhemiparesis

InstructionDescribe the non-contrast CT

brainDiagnosis

Suggest further investigation toconfirm the diagnosis


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Answer


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Generalized

brainoedema

Hypodensity

lesionatrightparieto-occipital

area

Hyperdensitylesionattheposterior

partofsuperiorsagittalsinus

D i i


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DescriptionCT

brain without contrastNormal skull, orbit and paranasalsinuses

Hypodensity area at right perieto-

occipital areaHyperdensity lesion in posterior partof superior sagittal sinus

Generalized brain swelling

Obliteration of lateral ventricles

No midline shift


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DiagnosisSagittal venous sinus thrombosiswith venous infarction at rightparieto-occipital area

How to confirm thediagnosis

Cerebral angiogramMRV

CTV

Venous sinus thrombosis


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Venoussinusthrombosis

EmptyDeltaSign

Case 7


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Case 7

40 years old man

Weight loss for 6 months

Headache and confusion for 2weeks


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Answer


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Multiplering

enhancinglesion


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DescriptionMultiple ring-enhancing lesion,which appears hypersignal on T2Wwith surrounding oedema, at right

basal ganglia, left basal ganglia, bothcerebellar hemisphere

Mild dilatation of ventricles

No midline shift


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Case 8


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Case 8

40 year old woman

Presented with blurred vision


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Answer


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Pituitary mass


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DescriptionEnhancing mass at pituitary fossawith supra sellar extension

DiagnosisPituitary macroadenoma withsuprasellar extension

DDx Craniopharyngioma

Special thanks


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Special thanks

Dr. Chotipat Danchaivijitr

For these beautiful slides andimages

Documents

Neuroimaging Resident