Brain Understanding Interpretation of Ct and Mri

8/12/2019 Brain Understanding Interpretation of Ct and Mri

1/67

BRAIN IMAGING

Interpretation of Brain CT and MRI

Angela Nelson, MSN, RN, CCRN,ACNP-BC

Department of Neurosurgery

I have no current affiliation or financial arrangement with

any grantor or commercial interest that might have direct

interest in the subject matter of this CE Program

9.4.79


2/67

Objectives

Identification of normal brain anatomy on

both CT and MRI imaging

Identification of common CNSabnormalities on both CT and MRI

imaging

Identification of appropriate radiographic

studies to be obtained for the more

common suspected CNS abnormalities

Brain Anatomy

Layers covering the Brain

SkinPeriosteumBone Cranium epidural

space is between dura mater andthe bone. Superior Sagittal Sinuslies here

Dura Mater hard mother(leather like)

Subdural space lies between duraand arachnoid

Arachnoid Membranespider (spider web)

Subarachnoid spaces liesbetween the arachnoid and pia

Pia Gentle Mother (thinlayer adhering closely to brain)

Cerebrum

4 Lobes: Frontal, Temporal, Parietal andOccipital

Falx Cerebri Separates the 2 hemispheres

Tentorium Cerebelli Separates the cerebellumfrom the Cerebrum

Gyri Rounded ridges on surface of brain

Sulci Shallow groves separating the gyri

Fissure Deeper groves

Gray Matter Unmylinated Nerve Fibers

White Matter Mylinated Nerve Fibers

9.4.79


3/67

Review of Lobes

Frontal-Personality, judgment, abstractreasoning, social behavior, language

expression and movement Temporal-Hearing, language expression,

storage and recall of memory

Parietal-Interprets and Integratessensations including pain, temperature,touch, size, shape, distance and texture

Occipital-Interprets visual stimuli

Right and Left-Cerebral Hemispheres

connected by Corpus Collosum

RightEmotion

Prosopagnosia

Music

Spatial Relationship

Left

Logic Brain

Speech

Math

Science

9.4.79


4/67

Falx Cerebri

9.4.79


5/67


6/67

Basal Ganglia

Corpus Striatum Caudate Nucleus

Lentiform Nucleus Putamen and Globus

Pallidus

Interconnected nuclear masses deep

within cerebral hemispheres involved in

the initiation of voluntary movements,

controls of postural adjustments

associated with voluntary movements

9.4.79


7/67

White/Gray Matter

White Matter

Consists mostly ofmyelinated axons(surrounded by a fattysheath containingmyelin) that connectvarious gray areas ofthe brain to eachother

Gray MatterContains cell bodies aswell as fibers of

unmylinated neurons

Gray matter includes thebasal ganglia (caudatenucleus, putamine,globus pallidus),thalmus, hypothalmus,subthalmus, andcerebellar nuclei

Cerebellum

Maintains muscle tone, coordinate muscle

movement and controls balance

A disorder of this area may causedizziness, nausea, balance and

coordination problems

9.4.79


8/67

Cerebellum

Brain Stem

Composed of Medulla Oblongato, Pons, andMidbrainMedullaAutonomic Function (HR, RR, BP)

PonsArousal

Respiratory

Midbrain Controls sensory response

Produces autonomic behavior necessary forsurvival

Pathways for nerve fibers between higher andlower neural centers

Origin for 10 of 12 pairs of cranial nerves

9.4.79


9/67

Medulla

Pons

Ventricular System

Contains the CSF

Composed of lateral ventricles, foramina

of Monro, the third ventricle, aqueduct ofSylvius, and the forth ventricle

Choroid Plexus located throughout thesystem makes the CSF

CSF leaves the ventricles through theforamina of Magendie and Lushka toreach the subarachnoid space

9.4.79


10/67

Lateral Ventricles

Foramen of Monroe

Third Ventricle

9.4.79


11/67

Aquaduct of Sylvius

4th Ventricle

Cerebral Circulation

9.4.79


12/67

Cerebral Circulation

MR Angiography

Internal Carotid Artery

9.4.79


13/67

Middle Cerebral Artery

Anterior Cerebral Artery

9.4.79


14/67

Venous Drainage

Venous Sinus Drainage

MR Venography

9.4.79


15/67

Computed Tomography

Nobel Prize Winner Sir Godfrey Hounsfielddeveloped CT for clinical use in 1972-1973

The first company to introduce the CTscanner was EMI (English MusicalInstruments)-the same company thatdistributed the Beatles on the Apple label

Grossman, R.I. and Yousem, D.M. The Requistes. Neuroradiology. Second Edition. Philadelphia, PA,2003

Computed Tomography Physics

Uses a highly collimated x-ray beam

Photons that pass through the patient are

collected by CT detectors which show a

differential rate of intensity on a gray scale

The beam is rotated across the patient at many

angles so as to get a differential rate of

absorption

Grossman, R.I. and Yousen, D.M. The Requistes. Neuroradiology. Second Edition, Philadelphia, PA, 2003

Indications of Use of CT

First line in evaluation of a change in mental status

Test of choice for those with implantable devices

Shows acute and sub acute blood (ICH/SAH, SDH)

Bony abnormalities, i.e. Trauma or fracture

Edema/Mass effect

Abnormalities in size and shape of structures

i.e. brain tissue atrophy, gyri effacement with swelling

Hydrocephalus

Hemorrhagic stroke

Add contrast if looking for tumor, abscess, or cerebralarteries and veins

9.4.79


16/67

Disadvantages of Computer Tomography

Poor imaging for demyelinating disease

Poor resolution in the posterior fossa of

the brain primarily due to streak artifactfrom the bones

Density gradients on CT

Bone

Calcification

Contrast material

Clotted blood

Some tumors with densely packed cells

Grey matter

White matter

Edema

Pus

Necrotic Cavities

CSF

Fat Air

How things appear on a CT?

Acute Blood/Calcifications-White

Chronic Blood Collection-Low density black to

gray as increasing density CSF/Air-Black

White Matter-Less dense than gray matter and

therefore will be darker

Ischemia-Lower density and therefore will be

darker and may not appear for 12 hours

9.4.79


17/67

Radiographic Images

What is on the left

side of the picture

represents the rightside of the patients

brain

Axial-top to bottom or

bottom to top

Radiographic Images

Sagittal-Side to side

T1

Radiographic Imaging

Coronal-Front to back

or back to front

9.4.79


18/67

Orbit

Spenoid

Temporal

Mastoid Air

Auditory

Cerebellum

Frontal Lobe

Sylvian Fissure

Temporal Lobe

Supracellar Cistern

Midbrain

4th Ventricle

Cerebellum

9.4.79


19/67

Falx Cerebri

Frontal Lobe

Anterior Horn

3rd Ventricle

Quadrigeminal Cistern

Cerebellum

Radiology Atlas.exe

Caudate

Ant Horn Lat Ventricle

Internal Capsule

Putamen/Globus Pallidus

3rd Ventricle

Quadrigeminal Cistern

Vermis

Occipital Lobe

Falx Cerebri

Frontal Lobe

Body of Lateral Ventricles

Corpus Callosum

Parietal Lobe

Occipital Lobe

Superior Sagittal Sinus

9.4.79


20/67

Falx Cerebri

Superior Sagittal Sinus

9.4.79


21/67

How to Approach a Read

View the Subdural windows for bony

defects, fractures

Are the sinuses opacified

Bony Windows

Soft Tissues (brain window)

View the lateral, 3rd and 4th ventricles

Are they enlarged, compressed, distorted,

diplaced

Is there anything in them other than

choroid plexus

Look for blood or debris especially in the

dependent portions

9.4.79


22/67

Brain Window

Is there a focal density abnormality in the

brain?

Is there something that is notsymmetrical?

Is it mass producing or volume losing?

Are midline structures midline?

Are the sulci symmetrical or effaced?

Are the lateral ventricles symmetrical?

Brain Window

Is the gray/white junction seen around

both cerebral hemispheres?

Is the insular ribbon seen?

Are the basal ganglia distinct from the

internal and external capsule?

Spinal Cord

9.4.79


23/67

9.4.79


24/67

Sinuses

Orbits

9.4.79


25/67

ExternalAuditoryCanal Mastoid

Air Cells

Medulla

9.4.79


26/67

Cerebellum

TemporalLobe

4thVentricle

4th

Ventricle

Basilar Artery

Pons

9.4.79


27/67

Basilar Artery

Supracellar CisternSylvian Fiisure

9.4.79


28/67

Frontal Lobe

Parietal Lobe

QuadgeminalCistern

Anterior HornLateral Ventricle

Third Ventricle

Vermis ofCerebellum

9.4.79


29/67

OccipitalHorns

Occipital Horns

Caudate Head

Choroid Plexus

9.4.79


30/67

Body of Lateral Ventricles

9.4.79


31/67

White Matter

Faux Cerebri

9.4.79


32/67

Central Sulcus

Pre Central Gyrus

Post Central Gyrus

Intraparietal Sulcus

Cental Sulcus

9.4.79


33/67

9.4.79


34/67

9.4.79


35/67


36/67

Meningioma/CT

Epidural Hematoma/CT

Glioblastoma/CT

9.4.79


37/67

Hypertensive Cerebellar Bleed/CT

Coagulopathic Bleed/CT

Chronic Subdural Hematoma/CT

9.4.79


38/67


39/67


40/67

Diffusion MRI

Diffusion Weighted Imaging (DWI)

Determines the ease of water diffusion

Can determine cerebral ischemia within minutes

of irreversible damage Most sensitive way of determining an acute

infarction

Good in differentiating vasogenic edema

(generally tracks along white matter and spares

the gray matter)

Appears as dark CSF, bright Fat and Lesions

DWI

Apparent Diffusion Coefficient (ADC)

Measures the brownian motion of protons

High ADC will be seen in CSF where there

protons can freely move

Low ADC will be found with new strokes

and tumors where they are more tightly

packed together

9.4.79


41/67

T1 Pre and Post contrast

CSF appears black

Subcutaneous tissue

(beneath the skull)appears white

Blood appears white

White matter brighterthan gray matter

Lesion will appear dark

Shows blood clearer

*Note-T1 post-sinus/nasal terbinates,choroid plexus bright

T2 MRI

CSF appears white

Subcutaneous tissueappears black

Blood appear white

White matter darker thangray matter

Shows older changes andmicrovascular

More accurate for brainpathology

Flair/Echo Gradient

9.4.79


42/67

Tonsils

Vertebral Artery

Falx Cerebelli

9.4.79


43/67

Vermis

Medulla, Verebral Artery, 4 th ventricle

9.4.79


44/67

9.4.79


45/67


46/67


47/67


48/67


49/67

9.4.79


50/67

9.4.79


51/67


52/67


53/67

Diffuse Axonal Injury

Frequent result of traumatic deceleration injuriesresulting in shearing of axons and small bloodvessels

Frequent cause of persistent vegetative state

Usually occur at gray/white matter junction

DAI suggestive in any pt who demonstratesclinical symptoms disproportionate to imagingfindings

Up to 90% of these patients remain in apersistent vegetative state, rarely die

DAI/Diffusion

Glioblastoma

Average age of diagnosis 50-70

Occur more commonly in men

Most patients die within 8-18 months

Clinical presentation depends on location

of the tumor; stroke like symptoms, focal

neurological deficits, headache, change in

behavior, seizure

9.4.79


54/67

GBM/T1/T2

Meniogioma

15% of all brain tumors

More common in women

Usually occur in 3rd to 6th decade of life

Discrete well defined dural masses

Can remain clinically asymptomatic for years as

they grow slow

Common symptoms include focal defecits,

seizures, headaches and psycho organic

syndrome

Meningioma/T1/T2

9.4.79


55/67

STROKE

CT is preferred for intracranial

hemmorhage

For non hemorrhagic stroke a CT can benegative for 24-36 hours

Flair/T2 MRI can detect in 6-12 hours

Diffusion MRI can detect within minutes

STROKE/Ct/T1

T1

T2

FlairDWI

9.4.79


56/67

Metastatic Tumor

66 year old right

handed female with

PMH mestatic lungcancer, s/p Right

Lobectomy with

radiation and Right

masectomy

1-2 months of slurred

speech, word finding

difficulty and lethargy

Exam:

Mild right upper

extremity drift, mildright dysmetria

Found to have left

temporal lesions

Patient started on

Anti-convulsants and

lesion resected

9.4.79


57/67


58/67

Presumed Metastatic Lesions

72 year old right handed malewith Prior history of CABG,AAA, Cardiac Stent, andrecently MylodysplasticSyndrome with a 4 day historyof dizziness and headaches,now with confusion andreceptive and expressivedysphagia

Exam significant for right sidedweakness, right drift, rightfacial droop, inability to followcommands

Anticonvulsants and IVsteroids initiated

Platelet count 6

Hematology consult-found tohave high grade Mylodysplasia

Transfused multiple units ofplatelets in an attempt to >150before OR

Patient developed AspirationPneumonia and surgery wasdelayed

Continued to deteriorate

CT Hemmorhagic Lesion

Large Left MCA Infarction

58 year old man withhistory of tobaccouse, HTN, BPH whowas in process orbeing worked up for atransient decreasedsensation in right arm

At work with suddenright sided weakness,right facial droop andaphasia

Found to haveocculsion of the leftinternal carotid arteryand M1 segment leftMCA thrombus

Given TPA withoutimprovement

9.4.79


59/67

Pituitary Macroadenoma

39 year old righthanded male with noPMH.

Developed fatigue 3years ago, treated fordepression, startedon Lexapro

Past 2 years noted adecrease in theamount of facial and

leg hair

Low testostone, LowLH

Visual fields normal

2.2 cm tumor

UnderwentEndoscopic TSSHapproach Resectionof Mass

9.4.79


60/67


61/67

Mystery Lesions

49 year old right handed

male with PMH of HIV,

AIDS, and Stoke presents

with a 3 week history of

headaches particularly

severe for the last 3 days

Exam significant for

dysarthric speech,

bilateral dysmetria, left

foot drop

Patient underwent

craniotomy with

pathology sent however

no cultures were sent.

Path inconclusive

Pathology inconclusive

Lesions/Old Infarctions

9.4.79


62/67

Arteriovenous Malformation

21 year old right handed malepresents with an acute onseton BLE numbness

Had a warm sensation

throughout his body, felt dizzyand faint with a headachewhich progressed to completeleft sided weakness

Exam significant for left sidedweakness although A/O x3

Angiogram Right frontal AVM

Underwent pre opAngio/Embolization of Lesion

AVM resected with post opAngio done

POD # 6 developedheadaches and CT revealedright frontal epidural hematomaand pt emergently taken to OR

9.4.79


63/67

Acute Cerebral Infarction of Pre-Central

Gyrus

63 year old right

handed, male with

sudden onset oftingling in right check,

inability to speak and

could not properly use

right hand

T2 Acute Infarction

9.4.79


64/67

Communicating Hydrocephalus

CSF circulation

blocked at level of

arachnoidgranulations

Multiple Sclerosis/Flair

Age of onset 10-59, withpeak between 20-40

Demyelinating disease ofwhite matter affecting thecerebrum, optic nervesand spinal cord

Typically hasexacerbations andremissions

Common symptomsvisual disturbances,spastic paraparesis andbladder dysturbances

Infarction with Hemicraniectomy

Pre op Post op

9.4.79


65/67

TraumaSubdural

IntraparenchymalSAH

Epidural

Cerebellar Hemangioblastoma

9.4.79


66/67

DWI

Infarction

ADC

Melonoma with hemmorhage

XXXXXXXXXX

9.4.79


67/67

Documents

Brain Understanding Interpretation of Ct and Mri