Introduction to Neuroimaging of Brain

8/3/2019 Introduction to Neuroimaging of Brain

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CT scan of head

most closely

resembles MR-FLAIR & is

identified by the

heavy ring of

skull bone (*)

*


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Whichneuroimaging

study is this &

why? Identify

heavy ring of

skull bone(*)

*


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CT scan of

head most

closely

resemblesMR-FLAIR

& identified

by the

heavy ring

of skull

bone(*)

*

ANS.

CT scan


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1

1

2

3

4

5

6

7

8

8

9

CT scan with sequences from

infratentorial to supratentorial.

Major structures are indicated by

arrowhead & numbers . Review

them here & try to name them onnext slide.

Arrowhead=basilar

artery

1=4th ventric

2=pons

a=cerebellum

Arrowhead=

qudrigemminal

cistern

3=vermis of

cerebellum

4=midbrain

Arrowhead=thalamus

5=lenticular nucleus (putamen

-lateral & globus pallidus-

medial)

6=third ventricle

7=caudate nucleus (head)

8= osterior limb internal ca sule

9=centrum

semiovale

0=lateral

venticle

0

a


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1

1

2

3

4

5

6

7

8

8

9

Name the structures mark by arrowheads & numbers .

In image on far left identify the black structure (#1) shaped like Napoleons

hat. The pons is anterior & cerebellum posterior to the 4th ventricle. The

basilar artery, is the round structure anterior to the pons (). In 2nd image

from left the midbrain is anterior to the quadrigemminal cistern () & the

vermis of cerebellum is posterior. The thalami are the walls of the 3rd

venticle (6) & the the globus pallidus is lateral to the internal capsule(8).

a


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DWI ADC FLAIR T2 GRE

The MR imaging sequences from left to

right are Diffusion-weighted imaging (DWI),

Apparent-diffusion coeficient (ADC),Fluid-

attenuation inversion recovery (FLAIR),

T2W & Gradient echo (GRE).

CSF is black in DWI & FLAIR with FLAIRappearing more in focus.Notice the anatomic

landmarks on FLAIR are similar to those

seen on CT images. Identify the seq to the

left & ID #1,2&3. No. 3 is the genu of corpus

callosum .

1

2

3


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The MR imaging sequences from left to

right are Diffusion-weighted imaging (DWI),

Apparent-diffusion coeficient (ADC),Fluid-

attenuation inversion recovery (FLAIR),

T2W & Gradient echo (GRE).

CSF is black in DWI & FLAIR with FLAIRappearing more in focus.Notice the anatomic

landmarks on FLAIR are similar to those

seen on prior CT images. Identify the seq to

the left & ID #1,2&3. What part of the corpus

callosum is # 3.

1

2

3

1=head of caudate

2=thalamus

3=genu of corp. call.

FLAIR


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Top row are CT scan sequences from

infratentorial to supratentorial. Bottom row

are the various MR imaging sequences can

you name them.

Hint: CSF is black in DWI & FLAIR with

FLAIR appearing more in focus.


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DWI is most helpful in dx of acute CVA ie.manifests + in < 1hr.

FLAIR seq. best in subacute/chronic conditions as MS,

neoplasm, degener dis. GRE (gradient echo) shows evidence

of blood products (deoxyhemoglobin) in macrophages 24 to 48

hrs after bleed ie. cavernous malf, ICH,dissecting aneury,SAH

& microbleeds.

What major category of brain disease are each of the

sequences most helpful diagnosing & why?


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DWI ADC FLAIR T2

GRE

Acute

cva(within

minutes to

hrs),brain

abscess

Acute

cva,abscess

Subacute-

chronic

process ie MS

plaque,

neoplasm,cva

(after > 6 hrs)

Blood producrts &

Calcium ie SAH,

microbleeds, ICH,

cavernous

angiomas, arterial

dissection (dev

over 1 to 2 days)

Same as

FLAIR


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Acute cva,abscess

1st to show

CVA6hrs)

Generally, besides

CVA only abscess

(+) on DWI acutely

Acutecva,abscess

Subacute-chronic

process ie MS

plaque, neopl,cva

Blood producrts &

Ca ie SAH,microbleeds, ICH,

cavernous angiomas

Same as

FLAIR

Best sequence to

show blood

products (at times

the only one).

Usually by 24-48

hrs

Best sequence to

show subacute-

chronic process

of above

conditions


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Acutecva,absc

ess

Acutecva,absc

ess

Subacute-chronicprocess ie MS

plaque, neopl,cva

Blood producrts &

Ca ie. SAH,microbld, ICH

DWI -Fungal abscess GRE-microbleeds

DWI ADC FLAIR

R- MCA Infarct at 12hrs


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T1W non-gado (L), gado-enhanced (R)

Another MR sequence is T1-weighted

performed without or with gadolinium

enhancement. Acute infarcts do not enhance

but other conditions as neoplasm & abscess

frequenty do. How does the MR below help

diagnostically in a pt. with sudden neurodeficit with hx of lung CA. T1W MR is also

helpful in identifying gross anatomic

landmarks particularly on sagittal view as

seen below at far right.

T1W sag


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Enhancement in the left occipital

lobe (arrowhead) was key in dx of

metastatic disease & ruling out

stroke.

T1-W non-gado (L) gado (R)


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1

2

3

4

5

6

7

8

9

a

b

c

d

e

f

1=corpus callosum (cc)

2=pons

3=4th ventricle

4=prepontine cistern

5=vermis of cerebellum

6=mammilary body

7=qudrigeminal cistern

8=quadrigeminal plate

9=medulla

a=spleenium of cc

b=superior sag sinus

c=midbrain

d=straight sinus

e=sphenoid sinus

f=3rd ventricle

g=optic chiasm

h=cerebellar tonsil

i=genu of corpus callosum

g

Below are key anatomic

landmarks on T1W sagittal MR.

Try to name them and name one

major disease entity that may

affect each entry. Next slide

gives answer.

h

i


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1

2

3

4

5

6

7

8

9

a

b

c

d

e

f

g

Below are key anatomic

landmarks on T1W sagittal MR.

Try to name them and name one

major disease entity that may

affect each entry. Use what you

learned from prior CT & MRimage landmarks in naming

these structures.

Next slide gives answer.

h


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1

2

3

4

5

6

7

8

9

a

b

c

d

e

f

1=corpus callosum,body (cc) (MS)

2=pons (Stroke, MS)

3=4th ventricle

4=prepontine cistern (SAH)

5=vermis of cerebellum (ETOH-atrophy)

6=mammilary body ( Wernickie enceph)

7=qudrigeminal cistern (herniation)

8=quadrigeminal plate

9=medulla (stroke, MS, neopl)

a=spleenium of cc (stroke, neopl)

b=superior sag sinus(cereb vein thromb)

c=midbrain (Stroke)

d=straight sinus (CVT)

e=sphenoid sinus (abscess)

f=3rd ventricle (colloid cyst, ICH)

g=optic chiasm (optic neuritis, Neopl)

h=cerebellar tonsil (Arnold Ch mlf, herniation)

g

h

Landmarks

with major

diseases

assoc with@

area.


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Stroke

Case History #1


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75 yo with

sudden onset

L sided

weakness.What type of

image is this

and what

findings if any

does it show.

Hint:

Skull bone

is dense /

prominent &

there are 4

features of

early

infarction


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What is

arrowhead

pointing to.

What are long

arrows

demarcating.

What is doublearrowhead

pointing to in L

hemisphere that

is missing on R

at (*).


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Answer:

Arrowhead pointing to

dense middle cerebral

artery sign.

Long arrows demarcate

R-MCA infarction

characterized by

attenuation (*).

Double arrowhead

shows preserved grey/

white junction (L), lost

in acute CVA as seen

on (R) (*) .


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What are each of the MR

imaging sequences in this

patient and how do they help

in dating the age of the

infarction ?


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DWI ADC FLAIR

Bright signal on DWI with

corresponding decreased signal on

ADC in asoc with intermediate

signal on FLAIR times the age of the

infarction to between 12- 48hrs old.


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DWI ADC FLAIR

Answer:

Arrowhead pointing to

dense middle cerebral

artery sign.

Long arrows demarcate

R-MCA infarction

characterized by

attenuation (*).

Double arrowhead shows

preserved grey/whitejunction (L), lost in acute

CVA as seen on (R) (*) .

Bright DWI & dark ADC

with intermed FLAIR

signal dates inf from 12-

48 hrs old

CT scan

MRI


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Case History #2


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Case Hx: 60 y.o. WM diabetic

dev sudden R arm & gait ataxia

along with N/V


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What is the imaging study

& describe the findings.

What is your plan for this

pt.


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Follow-up CT scan at 24

hrs. Describe the

findings.


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CT scan showing L cerebellar round

hypodensity( arrowhead)consistent

with infarct with assoc hydrocephalus

manifest by enlarged temporal horns

(arrowhead).


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Case History #3


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Case Hx: 32y.o. presented to an

outside ER with the worst HA ofher life


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What is the image & what does it show.


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Normal control

= SAH

(blood) in

prepontinecistern

CT scan with blood in prepontine cistern

(arrowhead) & both lateral venticlesconsistent with subarachnoid

hemorrhage.


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Case History #4


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Case Hx: 70 y.o. WM with hx of

hypertension dev sudden HA &inability to walk


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What is the image

& what is the

lesion?


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What problem has this hypertensive

cerebellar hemorrhage caused on CT ?


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Case History #5


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Case Hx: Mr D is a 78 yo with

afib rx with coumadin whopresents with a 1 wk hx of

severe HA

Wh t th i h t d it h &


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What s the image , what does it show &

why did it happen?


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What is bright area at

arrowhead ?


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Acute blood in pool of

subacute blood .


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42 yo HF with (-)

PMH presented to

HHER with abrupt

onset of not feelingwell with vomiting,R

hemiparesis & LOC.

What does CT show , what isDDx & what study would you

order next & why,


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What does this CTA show?


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Infectious Disease

Case History # 1

HPIHPI


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HPIHPI

82 yo female admitted to the ER, after being found on82 yo female admitted to the ER, after being found onher bathroom floor confused, agitated with left facialher bathroom floor confused, agitated with left facial

bruises.Last seen well 2 days prior. PMH R ACA infarctbruises.Last seen well 2 days prior. PMH R ACA infarct

3yrs ago.3yrs ago.

Exam:T=101.4, L gaze dev, PERRLA, L hemiparesisExam:T=101.4, L gaze dev, PERRLA, L hemiparesis

leg> arm,leg> arm,


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LaboratoryLaboratory

15.4 134 95 2515.4 134 95 2516.8 214 20316.8 214 203

(85% g.)(85% g.) 44.1 3.5 30 0.844.1 3.5 30 0.8

CK = 1973 Trop T< 0.01CK = 1973 Trop T< 0.01

CXR: No acute disease.CXR: No acute disease.

U/A : 0 WBCU/A : 0 WBC


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CT HEAD

CT


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What do you consider in the Diff Dxand

What do you do next


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CSF:CSF:

ClearClear

Tube #4: 37 WBC (33 lymphs, 4 monocytes).Tube #4: 37 WBC (33 lymphs, 4 monocytes).

9 RBC9 RBC

Glucose: 127Glucose: 127

Proteins: 31Proteins: 31

Because of increased temp=101 &

increased WBC=16K in absence of

findings for CVA an LP is warrented.

Do you want any other studies inviewof the CSF findings?

CTCSF shows


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DWI

CSF shows

pleocytosis & in

conjunction with

confusion, temp &

elev WBC need to R/

O encephalitis. WhatMR seq is shown &

what abn is seen?

DWI

DWI seq is on top row, what seq is on bottom row &which seq is most helpful in this condition & why ?


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DWI

FLAIR

which seq is most helpful in this condition & why ?

DWI

DWI seq is most helpful for encehalitis esp for herpes simplexenceph (HSE) as early dx is important for rx with antiviral as


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DWI

FLAIR

p ( ) y p

acyclovir. DWI + in mesiotemporal region (typical for HSE)befor

changes are apppreciated on CT or FLAIR. What other test would be

helpful?


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EEG:EEG:

PLEDs over the right temporal lobe.PLEDs over the right temporal lobe.

CSF: HSV1 pos.CSF: HSV1 pos.


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Neoplastic Disease

Case History # 1


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Case HistoryLL

75 yo WM was adm 7/06 withcontinuous seizures of the R side.

One and half yrs ago he sufferedbilateral occipital & cerebellar strokefollowing aortic surgery & 8 moslater he was Dx with lung CA.

CT & MR of head on this admshowed L occipital hypodensity inPCA distribution.


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DWI seq is + in < 1hr after CVA .

This MR seq was done < 2hrs, which is it?

What brain structures are involved?

What dx is likely & why? Stroke,neopl etc.

Cyotoxic edema seen with stroke involvesboth cortex & white matter vs vasogenic


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DWI 1-5-05

1st adm

Brain struct. Invol: cerebellum, occipital lobe

Both are in distribution of post. Circulation.

Stroke best dx bec of + DWI early & edema

type.

What is type of edema? (cytotoxic v vasogenic)

both cortex & white matter vs vasogenic

edema seen with neoplasm where only

white matter is involved.


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CT 7-28-06 11/2 yrs later

Current adm

What is image type & describe the

lesion?

Is attenuation incr/decreased or both?

What type of edema is seen?


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CT 7-28-06 11/2 yrs later

This CT scan shows a L occipital lesion withfinger- like extension of edema seen with

neolpasm (vasogenic) edema.

The signal is mixed with increased signal

suggesting neolplasm . CVA is always

decreased signal unless complicated by

Vasogenic edema spares the cortex

but involves white matter & manifest


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FLAIRDWI

7-28-06

but involves white matter & manifest

increased signal on FLAIR.

This MR shows____edema?

How does this differ from cytotoxic

edema seen with infartion?

This non-enhanced (L) &enhanced (ctr/R)T1W MR

shows a feature of ring


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T1 Gado 7-29-06

shows a feature of ring

enh.seen mainly with neopl,

abscesses & subacute inf.

How were this pts. CT

abnormalities helpful in dx?

Given this hx the likely dx is?

T1W non-gado


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Diagnosis

Dx in 1-05 Cerebellar & L occipital lobe

infarction (early + DWI with cytoxic

edema)

Dx in 7-06Metastasis to L occipital lobe

from lung CA (small area of incr sig on CT,

vasogenic edema on CT/MR with ringenhancement on gad study


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Message

Apprecite vasogenic vs cytotoxic edema

need to enhance image to avoid misdx

unusual features for CVA: (-)DWI, atten

on CT, vasogenic edema

mets to occipital lobe can mimic PCA

infarct


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Demyelinating disease

Case history #1


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Acute

cva,abscess

Acute

cva,abscess

Subacute-

chronic process

ie MS plaque,neopl,cva

Blood

producrts& Caie

SAH,microbld,

ICH


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Introduction to Neuroimaging of Brain

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