Arteriovascular Malformation

abnormal connection between veins and arteries in the brain or spinal cord.

Usually congenital

Arteriovascular malformation

AVM

Muscle weakness on one side of the body only

Common muscles in the face arm and leg of effected side

Due to the breakdown of the blood brain barrier - fluid leaks out of the capillaries.

Associated with tumours and abscesses.

Typical finger like projections within tissue.

Affects white matter ONLY.

Swelling of all cellular elements

Causes mass effect

Associated with cerebral ischemia and hypoxia

Involves both grey and white matter

Old Oprah Occasionally Tries Trigonometry And Feels Very  Gloomy Vague And Hypoactive

Olafactory, Optic, Occulumotor, Trochlear, Trigeminal, Abducens, Glossopharyngeal, Vagus, Accessory, Hypoglossal

Olfactory - Sensory, Optic - Sensory

Occulumotor - Motor, Trochlear - Motor 

Trigeninal - Both, Abducens - Motor

Facial - Both, Vestibulocochlear - Sensory

Vagus - Both, Glossopharyngeal - Both

Accessory - Motor, Hypoglossal - Motor

Some Say Money Matters But My Brother Says Big Boobs Matter More

Central Nervous system - brain and spinal cord

Peripheral Nervous system - peripheral nerves - connects limbs to central nervous system

Autonomic Nervous system - Parasympathetic and Sympathetic

Inhibits the physiological effects of parasypathetic

Reduces digestion secrations

Speeds up hear rate

Causes blood vessels to contract

Orginates in thoraci and lumbar regions of the spinal cord

Opposite effect to sympathetic

Dominant when body relaxed and unthreatened

Activities tend to result in energy being stored and conserved.

Neurons emergy from cranial nerves 3 7 9 10 and sacral nervs 2 3 4

Pre-central gyrus

All voluntary movements initiated here

Nerve impulses pass along axons to effect opposite side of body - decussation of pyramids

Body represented up side down - homunculus

Post central Gyrus

Recieves sensations from axons from sensory organs on the opposite of the body

Sensory decussation

Homunculus - feet first mouth last

Most highly developed part of brain

3 types of activity ->Mental, sensory perception and initiation control

Located in occipital lobe

Recieves impulses from retina transmitted through the optic neve - Cranial Nerve II

Sensory Speech

Interprets spoken or written word

Located in lower parietal lobe extending into temporal lobe

Motor Speech

Located in frontal area just above lateral sulcus - left hemisphere

Initiates speech

Causes voluntary movements which produce speech

Lies on the inner surface of the left and right cerebral hemisphere

Not a seperate system - made up of cerebrum, midbrain  and the diencephalon

The emotianal brain - responds to sensory stimuli detected at body surface

Associated with Pain, pleasure, affection and anger

Smell

Group of cells located in temporal lobe

Recieves impulses from Cranial nerve I - Olfactory Nerve

Located in temporal lobe below lateral sulcus

Interprets impulses from inner ear - transmitted through vestibulcochlear Cranial Nerve VIII

Taste

Located in lower aspect of poste central gyrus

Recieves impulses from tongue

Link between correspoding gyri of each cerebral hemisphere.

They crossover the midline at corpus collosum - largest collection of commisural fibres

Connect cerebral cortex to other part of CNS such as brain stem and spinal cord.

All pass through diencephalon

Influence skeletal muscle tone

Control subconsious contractions of skeletal muscle - laughing at joke, swinging arms when walking

Also associated with attention memory and planning.

Connects cerebral hemispheres above to pons below

Extends from pons to diecephalon

Relays impulses to and from cerebral hemispheres

Relay station for auditory and optic nerves

Contains aquaduct of sylvius - connects 3rd and 4th ventricles

Located below mid brain in front of cerebellum and above medulla oblongata

Orgion of Cranial Nervs 5, 6 and 7

Reflex actions such as respiratory response

Forms part of 4th ventricle

Assists in control of movement and involvein sleep control and arousal

Above foramen Magnum

Continues from pons to the spinal cord

Decussation of pyramids - Decesing motor cross over

Sensory Decussation - asending sensory cross over

Contains vital centres concerned with reflex activities - Cardiac Centre, Respiratory Centre, vasomotor centre

Vomiting, coughing, sneezing and swallowing

Major relay station for sensory nerve impulses

Directs them to specific areas of the body and can interpret crude sensations

Has a role in motor function by transmitting infro from cerevellum and basal ganglia to motor cortex

3rd ventricle seperates left and right thalamus

Located beneath the thalamus - linked to pituitory gland

Influences hormonal secreations of pituitory

Has major role in homeostasis

Primary link between nervous system and endocrine system

Functions:

Regulated eating and drinking

Secretes ADH - increase reabsorption of h2o by kidneys

Secreates oxytocin - stimulates lactaion and contraction of uterus muscles in labour

Regulates emotion and behaviour

Split into anterior and posterior lobes

Secretes hormones: Thyroid stmulating hormone, Growth hormone, prolactin, follicle stimulating hormone, luteinizing hormone

Output of hormones stimulated by pituitary

TOugh Mother - Composed of dense fibrous tissue

Covers brain loosley

Composed of 2 layers

Outer periostral layer adheres to periostium of cranium

Inner layer protects brain and is dura mater proper

Outer layer ends at foramen magnum

Inner layer covers spinal cord fuses with periosteum of cocyx

Middle layer - Spider mother

Soft, thin, delicate translucent membrane

Loosly covers brain

Subdural space seperates dura from arachnoid

2 layers - outer layer next to subdural space, inner system of supporting fibres called trabeculae seperating arachnoid from pia mater.

Spaces contain CSF

Follows dura mater into fissures

Terminates at S2 where fuses with dura.

Acrachnoid villi perforate parts of dura in the venous sinuses - allows csf to exit and enter blood stream.

Dutiful Mother

Microscopically Thin

Highly Vascular

Adheres closely to brain - dips in all gyri

Impermeable to fluids so encloses csf and protects brain.

ALoows blood vessesl to pass through to nourish the brain

Covers spinal cord - continues as filum terminale

Pierces duran and arachnoid matter to fuse with periosteum of coccyx

Righ and left ventricles

Located in righ and left cerebral hemispheres

Anterior horn extends into frontal lobe

Posterior horn estends into occipital lobe

Inferior horn extends laterally into temporal lobe

Communicates with 3rd ventricle via foramen monro

Located anterior to cerebellum posterior to the pons

Is diamond shaped

Ingeriorly continues with central canal to spinal cord

Long and thin - losenge shaped

Located between thalamus and hypothalmus

Connected to 4th venticle via aqeduct of midbrain

Produced by cord plexus - located in ventricles and central canal of spinal cord

CSF flows through ventricles into the cisternum magna to the subarachnoid space to surround the brain and spinal cord in the central canal.

Consists of water, amino acids, glucose and mineral salts.

Support and protect brain and spinal cord

Maintain pressure around brain and spinal cord

Act as a shock absorber

Keep surface lubricant

Allows substances to pass between itself and nerve cells

Links brain to organs of the body

Extends from medulla to L1/2

Pointed end is conus medullaris

Anchored by filim terminale - continuation of pia mater

8 Cervicle, 12 thoracic, 5 lumbar, 5 sacral & 1 coccyx nerve fibres

Fibres below conus medularris = Cauda equina

CSF flows around in subarachnoid space to S2

Composed of white matter outer and grey matter inner

White outer

Grey centre

Grey matter H shaped - 4 horns - anterior and posterior

Transverse commisure - central canal runs through

White matter divided by grey matter - Anterior, posterior and 2 laterals - consists of sensory fibres carrying impulses to brain (anterior and posterior) and motor fibres carrying impulses away from brain (laterals)

Patient with sudden motor leg weakness

Acute intracerebral haemorrhage

In anterior cerebral artery terriotry

Patient presented with acute dysphasia

Acute ischemic infarct of middle cerebral artery territory

Blood supply to brain is distrupted

Due to occlusion or rupture of blood vessel supplying the brain or within the brain

Cells become starved of oxygen damaging them and causing them to die off

Short lived (less than 24 hours) temporary impairmetn in brain function caused by an insufficent supply of blood to the brain.

Caused by a temporary or partial occlusion of a blood vessel supplying the brain.

Usually no permanet brain damage

But likely to lead to an acute stroke

NICE Guidelines on Stroke

National Institute for Clinical Excellence

Recognised stroke as a major health problem in the UK

Concerned with the diagnosis and inital management

Improve chance of survical and recovery without disability

Introduction of new diagnostic methods, specialist stoke centres, new treatment - drugs, procedures

Assesment of TIA patients for risk of stoke - treatment to reduce chances

Rapid diagnosis, admission to specialist stroke unit, thrombolysis when indicated

Faster patient treated and diagnosed greter the options for limiting damage.

Staffed by specialist stroke multidisciplinary team

Must have access to equipment for monitory and rehabilitating patients.

Must be a discreate area within the hospital

Must hold regular multidisiplinary team meetings for goal setting

ABCD2 - prognosis score to indentify people at high risk of stroke after a TIA

FAST - Face, Arm, Speech, Test - screen for a diagnosis of stroke or TIA

ROSIER - Recognition Of Stroke In Emergency Room - Confirms a diagnosis of stroke.

Depressed level of consciousness (Glasgow Coma Score below 13)

Serve headache on onset of stroke symptoms

Indications for thrombolysis

TIA NOT indication for immediate imaging

Immediatly = next slot or within 1 hour which ever is soonest

ASAP = within max of 24 hours of symptoms

MRI unless contraindicated

Assesed within 24 hours

Aspirin started immediatly

Only scanned immediately if ABCD2 shows high risk of stroke - score of 4 or above and vascular territory or pathology uncertain

Considered as a treatment for acute ischaemic stroke if patient presented with in 3 hours of onset of symptoms

6 hours too late

NOT used if eveidence of haemorrhage

ONLY administered by staff specially trained

Surgical Procedure

Involves removal of plaque from the common carotid artery

Reduces stenosis and helps reduce risk of embolism

Treatment for TIA

Requires carotid imaging within week of symptoms

Staff work patterns have been altered to provide 24 hour service

Need to be rapid acess to imaging - scanner within a&e

Prioretise workload

Services altered to adhere to guidelines

CT for acute stroke

MRI for TIA

CT/MRI angiography for carotid vessels

CT/MRI for functional imaging in potenital thrombolysis patients.

New qualified radiographers expected to perform CT head scans

Numbness, weakness.

Paralysis of one side of the body - stroke in righ lead to paralysis of left - decussation of pyramids

Sudden vision loss

Dizziness

Difficulty swallowing

Communication problems

Balance/co-ordination problems - ataxic gate - stroke in cerebellum

Sudden serve headache

Worst stroke - brain stem - controls functions essential to life

F - Face - Can the person smile? Eyes and mouth drooped?

A - Arms? Can the patient raise both arms?

S - Speech? Can the person speak clearly?

T - Time/ Test - Test all 3 symptoms and act fast

Negatively charged proteins and organic compounds accumulate within the cell.

They attract positive ions causing osmosis of water into the cell

Equilibrium needs to be maintained via NaK pump or cells will burst and swallow due to build up of Na increasing osmosis of water

3 Na- leave cell in exchange for 2K+ through transport protein - requires breakdown of ATP to transport ions.

If arterial blood supply to an area of a brain is interupted due to vascular occlusion or haemorrhage - causing rapid infarction (tissue death).

Cellular level - ischemia (lack of blood supply) occurs resulting in cell hypoxia (lack oxygen) and decreases cellular ATP - source of energy to maintain equilibrium.

Lack of ATP results in built up of Na causing increase of osmosis and H2O within cell causing it to swell rapidly and burst - death - Cytoxic Oedema.

Ischaemic infarct - interruption of blood supply due to occlusion (blood vessel blockage)

Haemorrhagic - result of a rupture of a blood vessel or abnormal vascular structure - AVM - subarachnoid & intracerebral haemorrhage.

Thrombus - blood clot

Embolism - travelled blood clot

Systemic hypo-perfusion - decrease in blood supply - when in a state of shock

Venous thrombus 

Ill defined

Low attenuation

Left middle cerebral artery territory

Mass effect - effaced left lateral ventricle and left sulci and gyri

No evidence of midline shift

No evidence of haemorrhage

Acute Ischamic Infarct of Left middle cerebral artery.

Less than 1 cm in size

Occur in deep parts of the brain and brain stem

Caused by occlusion of single deep penetrating artery

Can cause serve neurological deficit compared to larger stroked due to location

Results in rupture of blood bessel within the brain

Prognosis poor

High fatality rate

Commonly due to hypetension, cerebral aneurysm or vascular malformation - AVM

Common in basial ganglia due to delicate vessels

Location more important than size

Blood and oxygen prevented from reaching brain cells beyond the rupture

Leaked blood irritate and harm the brain cells in the area they accumulate

Mass effect can cause raised intercranial pressure

Right frontal/parietal intracerebral haemorrhage

Mass effect - midline shift to left

Effaced right lateral ventricle and adjacent sulci and gyri

Possible intraventricular extension into left lateral ventricle

Caused by bleeding from a damaged blood vessel in subarachnoid space.

Blood accumulates in subarachnoid space.

Increase in pressure irritates, damages and destroys cells

Blood mixes with CSF potenitally blocking flow of CSF increasing pressure

Ventricles may enlarge - hydrocephalus

Vasospasm may occur causing delayed ischamic infarct

Subarachnoid Haemorrhage

Typical star of david appearence

Subarachnoid haemorrhage 

Hydrocephalus of inferior horns of the lateral ventricle

Loss of Sulci and gyri

1. Anterior Communicating Artery

2. Anterior Cerebral Artery

2a. Middle Cerebral Artery

3. Carotid Artery

4. Posterior Communicating Artery

5. Posterior Cerebral Artery

6. Basilar Artery

7. Vertebral Artery

Anterior = Gold

Middle = Pink

Posterior = Blue

Anterior Cerebral Territory

Causes leg weakness if in motor cortex

Middle cerebral Territory

Face and arm weakness greater than leg

Aphasia - difficulty with language

Dysphagia - Diffuculty in swallowing

Posterior Cerebral Territory

Visual field defect

Most distal areas between arterial territories

Seen in cardiac errect, regional hypotension and anaphylaxis reaction

Ataxia - loss of control of muscles

Vertigo - loss of balance

Coma - loss of consiousness

Treatment dependant on type of stroke

Ischaemic stroke requires increase in blood flow - thrombolysis

Haemorrhagic stroke requires blood flow to be inhibited

Incorrect ttreatment life threatening

ACE inhibitors to lower blood pressure and prevent further stroke

Emergency crainotomy to remove clot and reduce pressure

Aspirin and anticogulants used to thin blood and prevent clots and reduce chances of further clots

Statins to block liver enzyme producing cholesterol

Diuretics to reduce water in body

Carotid endarterectomy

Edge of infarction is ischaemic penumbra

If blood flow is restured cells recover function

Breaks down blood clots

Only effective within first 4 hours of symptoms

Can cause serious bleeding if administered incorrectly

Contrast administered

Contrast enhancement provides information on cerebral blood flow, regional cerebral blood flow, regional cerebral blood volume and blood mean transit time.

Critical for thrombolosis treatment indicates tissue viability and haemorrhagic risk.

Minimally invasive

Provides views telling the tale of blood flow volume and transit time

CT is readily avaliable, cheaper, quicker and more accessible than MRI

CT modailty of choice in acute setting due to:

Widely avaliable

Relatively inexpensive

Faster scanning time and reviewing of results

Few contraindications for CT

MRI not sensitive to acute haemorrhage

Difficult cases

Follow ups

Functional studes

TIA

Hyperacture Infarction

Within 48 hours of infarction

Ill defined

Hypodense

Hyperdense middle cerebral artery

Obstruction of lentiform nuculeus

Insular ribbon sign - loss of differentation of white and grey matter at sylvian fissure and basal ganglia

Hyperdense Middle Cerebral Artery

Hyperacute cerebral infarct

Obstruction of lentiform nucules

Hyperacute infarction

2-7 days after infarction

Ill defined

Wedge shaped involving grey and white matter

Hypodense

Increasing mass effect

Effaced adjacent sulci and gyri

28 days plus

Well defined wedge of gliosis/encephalomalacia

Hypodense

Associated expansion of adjacent ventricle

Atrophy

Sulcal widening

Often only appear on CT after 24 to 48 hours later

Peaks at 3-5 days

Hyperdense

Mainly males

1/5 over 65

Half children

2/3 adults involve alcohol

60% deaths RTA

50% deaths  trauma

RTA

Falls

Assults

Sporting and leasure accidents

Often associated loss of consiousness

Leads to pernament or temporary impariment of cognotive, physical and psychological function

Extradural haemorrhage

Subdural haemorrhage

Subarachnoid Haemorrhage

Intracerbral haemorrhage

Contusion

Occurs within brain tissue

Intracerebral haemorrhage

Intraventicular

Within skull vault but not in brain tissue

Extradural haemorrhage

Subdural haemorrhage

Subarachnoid haemorrhage

Measures Consiousness

Higher the score the more responsive the patient

Best Score 15 Lowest 3

Eye Response - 4- spontaneous, 3- to verbal stimuli, 2- to pain, 1- no response.

Motor Response - 6- obays command, 5- localises to pain, 4- withdraws to pain, 3- flexion to pain, 2- extension to pain, 1- no response

Verbal Response- 5-orintated and converses, 4- disorintated and converses, 3- innappropriate words, 2- incomprehensible sounds, 1- no verbal response

Compression of 3rd cranial nerve occulumotor

Causes reduced pupillary response

Pupil will be fixed dilated on opposite side to pathology

Once patient ventilated pupils only way to tell of deteriation

TBI NICE guidelines

OBS and Immediate imaging

Allows head injuries to be dealt with confidently and prevents haemorrhages being missed

GCS and pupillary response checked half hourly

Immediate CT required if:

GCS below 13

GCS decreases within first 2 hours

Focal neurological deficit

Post traumatic seizure

More than on episode of vomiting

Amnesia of events over 30 mins prior to incident

Loss of consciousness and over 65

Loss of consciousness and dangerous mechanism - ejected from motor vehicle, pedestrian hit by motor vehicle, fall from height greater than 1 meter, or 5 stairs or more

CT preferred - faster, accessible and easy to interpret.

MRI not modality of choice in acute haemorrhage

Caused by mass effect

Skull vault is fixed no room for expansion

Expansion occurs in haemorrhage, tumour and oedema causing an increase of pressure in the cranium causing compression of brain tissue and possible midline shift.

Effaced ventricles or hydrocephalus

Effaced suprasellar cisterns

Coning

Coning

Compression of brainstem

Forced through foramen magnum

Brainstem controls essential functions to life - coning = life threatening.

Associated with compression of cranial nerve III - occulomotor

Duret haemorrhage - brainstem haemorrhage

Caused by increase in intracranial pressure

Typically affects young patients

Dura matter adheres tighter to the cranium with age

Requires trauma to tea dura from bone

Skull fractures present in most cases

Stripping of dura causes laceration of arteries leading to haemorrhage

Dura is inseparable at sutures so haemorrhage confined by tear in dura and adjacent suture.

Trauma - Assult, fall or other accident.

In newborns due to difficult labour and forceps delivery

Young patient involved in clearly defined blow - RTA, sport accident

Serve headacehe - caused by dura stripping away from bone

Loss of consiousness depending on force

Classic lucid interval - patient gains normal consiousness

but extradural haemorrhage continues expanding increasing mass effect increasing intracranial pressure resulting in coning and rapid loss of consiousness

Usually acute - Hyperdense

Typical bi-convex/lentiform shape

Limited to sutures of cranium

Well defined

Most common in temporal lobe

Often associated fracture

Pneumocephalus - air in cranium commonly seen

Often associated mass effect

Surgical - Evacuation of the haemorrhage - follow up ct to assess for clot evacuation and formation any new haemotoma

Close clinical observation for any signs of expansion - CT if nerological decline

Prognosis dependant on initial symptoms

If haemotoma removed quickly good prognosis

Occurs between dura and arachnoid mater - subdural space

Common in elderly patients, patients with clotting disorders

Associated with serve or minor head injury

Associated with NAI - shaken baby syndrome

More common in men than women

Bridging veins tear - associated with atrophy (shrunken brain)

Low pressure venous bleed

Atrophy causes greater tension in bridging veins making them easier to rupture even in minor trauma

Patient may or may not be consious

High rate of mortality and morbidity

Isointense

Cresent shaped 

Blood spread over the cerebral convexity

Can cross sutures but not midline

Can be bilateral

Marked mass effect = increased cranial pressure

Often mixed hyper/hypodense - blood mixing with csf or repeating bleeding causing layering

Size matters

Less than 1 cm, asymptomatic - regular obs and follow up CT

Greater than 1cm, midline shift, increased intracranial pressure, low GCS - surgical intevention - crainotomy and evacuation of haemorrhage

Subdural falx cerebri

Betwen arachnoid and pia mate - subarachnoid space

Spontanous - stroke - ruptured cerebral aneurysm

Traumatic - near site of fracute or intrcerbral contusion

Women greater risk than males over 65

Risk increases with age

Mostly aneurysm rupture

AVM

Extension intracerebral haemorrhage

Venous haemorrhage

Head trauma

Leads to death or serve disability - half fatal

Thunderclap headache - worst ever

Neck stiffness

Photophobia

Vomiting

Seizures

Decreased level of consioisness

Confusion

Can occur alone or with intra/extra cerebral hamorrhage

Haemorrhage seen in csf spaces - cisterns, sulci or fissures

Haemorrhage of suprasellar cisterns have typical star of david appearence

Lumbar puncture can confirm blood in csf

CT exclude contraindications for lumbar puncture because if increased intracranial pressure - coning induced

Vasospasm leading to ischaemia

More common than subarachnoid

More likely to result in death or serve disability

Braistem intrcerebral haemorrhage - very high mortality

Age

Hypertension

More common in males and african and asians

AVM/ Aneurysm

Alcohol/drug abuse

Head trauma

Sudden onset of focal neurological deficit

Headache

Nausea

Vomiting

Decreased consiousness

Elevated blood pressure

Stabilise patient

Protect airway

Reduce blood pressure

Consider surgical evacuation of blood clot

Hyperdensity

Rim of hypodensity indicating oedema

Mass effect

May have intraventricular extension

Appears hypodense after 2-4 months

Intracerebral Haemorrhage with intraventricular extension

Intracerebral haemorrhage anterior cerebral artery

Hypodense after 2-4 months

Bruising of the brain

Direct trauma

Acceleration/deacceleration injury

Often occurs in frontal and temporal regions due to brain colliding with bony protuberances within the skull

Often small haemorrhages - hyperdense

Wedge shaped

Associated oedema

Results in areas of tissue death - hypodense 

Common in head traumas

Occur in moderate and mild brain injury

Major cause of uncosciousness and persistant vegative state

Patients with serve diffuse axonal injury rarely regain consiousness or are servely disabled

Rarely causes death because brainstem rarely affected

Due to rapid acceleration or deacceleration of brain within skull

Causes traumatic shearing of axons

Commonly occurs at grey/white matter junction

Axons within white matter disrupted

Often widespread area

May not be seen on ct or MRI

Multiple haemorrhages at grey and white matter border

Most patients have normal initial ct

Delayed scan demonstrats oedema and atrophy

MRI preferred imaging technique

Not always visible

Fluid levels in sinuses indicated presence

Indicated clinically by battle sign or racoon eyes

Surgery may be required to elevate bone fragment

Antibiotics to prevent infection

Occur at any age

2 peaks of incidence - Childhood and early 70s

Over half occur in over 60

Pt lies supine with head first

Arms by side

Chin down

Radiographic base line - line joining outer canthers of eye to external auditory meatus - 90 degrees to table

Median sagittal plane - divides head equally into left and righ halves - 90 degrees to table

Interpupillary line - joins centre of 2 orbits - 90 degrees to msp

Centre to lower orbital margin at level of EAM

AP and lateral Scouts

2.5mm slices reconstructed to 1.25mm

Whole skull vault - vertex to foramen magnum

No evidence of rotation - lateral border of orbits equidistant from the latral boarder of the skull

No evidence of tilt - petrous ridges horizonatal

Petrous ridges below orbits

Scan block angled to anterior cranial fossa - reduces radiation dose to the lens of the eyes

Chin up

Median sagittal plane - 90 degrees to table

Anthropolgical baseline - line joining infraorbital margin to superior boarder of EAM - 90 degrees to table

Interpupillary line - 90 to median sagital

Centre to lower orbital margin at level of EAM

AP and lateral scouts

Head scan field of view

Scan block to include all sinuses - inferior aspect of maxillary sinus to superior aspect of frontal

Scan block parrallel to hard palate

Cronal reformats - posterior of sphenoid to anterior of frontal

2.5mm slices reformatted to 1.25mm

Antropological line - lower orbital margin to superior border of EAM - 90 to table

Median Sagittal plane - 90 degrees to table

Inter-pupillary - 90 to MSP

Centre to lower orbital margin at level of EAM

AP and Lateral Scouts

Head field of view

Scan block to include all of orbits and incase in fracture of of maxilla

Scan block alinged parallel to optic nerve

Coronal and parasagittal oblique reformats

Coronal to include les of eye anteriorly and optic chiasm posteriorly

Parasagittal oblique parallel to optic nerve to include lateral and medial borders of the bony orbit

Occipito-mental/ Occipito-mental 30 Imaging Technique

Patient erect

MSP - 90 to receptor

IPL - 90 to MSP

RBL - 45 to receptor

CP - midline through vertex of anterior nasal spine

OM30 - 30 degree caudal tilt

No rotation - distance from lateral margins of orbits equidistant from latral borders of skull

No tilt - petrous ridges parallel

om- petrous ridges below maxillary sinuses

om30 - floor of orbit projected through maxillary sinuses

Erect affected side in contact with receptor

MSP - parallel to image receptor

IPL - 90 to receptor

CP - 2.5cm inferior to outer canthus of the eye

CR - 90 to image receptor

Floor of anterior cranial fossa and facial bones superimposed

Modifided submento-vertical

Jug handle projection

Patient supine

Neck extended until long axis of zygomatic archs parallel to receptor

MSP - 90 to image receptor

IPL - 90 degrees to msp

RBL - parallel to image receptor

10 degree tilt away from effected side - clear skull

CP - Midway between EAM or midpoint of zygomic arch if one being images

MSP - paralle to receptor

Chin raised to clear angle of mandible

Shoulder relaxed

Exposed on arrasted inpiration

CP - Midline of next level of thyroid eminence

CR - 90 to image receptor

SID - 180cm

Vertebral bodies superimposed

Angle of mandible cleared from pharynx

Exposure clear to demonstate soft tissue neck

Lateral soft tissue margina

Superiorly - nasopharyns

Inferiorly - T1

Same as Lateral soft tissue neck

CP - midline at level of nerbal notch

Collimate to include lateral soft tissue borders, naspharynx to carnia