Group2city's Blog

MAGNETIC RESONANCE IMAGING

group2city — Sun, 05 Apr 2009 15:24:09 +0000

MRI Equipment

Patient table
• To securely hold and transport patient into the scanner

Electromagnet
• Series of wire coils through which voltage is passed to produce magnetic field
• To align the nuclei into their different energy states

Radio Frequency source
• To excite the nuclei and flip the magnetic vector

Radio frequency receiver coils
• Made to fit various body parts
• They receive MRI signals
• Head coil is used in the case of Stroke patients

Magnetic field gradient coils
• To determine the spatial location of signals

Image processor
• Processes signals by Fourier transformation to encoded computer language

Computer system
• Processes the information for display
• Serves as the operator interface to control the different processes

Retrieved from http://www.cis.rit.edu/htbooks/mri/chap-9/images/mri9-1.gif
Basic Principles of MRI
1. Basic Principles o MRI
• MRI works on the principle that protons from the nucleus of Hydrogen spin and behave like tiny magnets
• When under the influence of an external magnetic of 1.5 telsa they align themselves with or against the field creating a Nuclear magnetic vector
• The nuclei (Protons) also presses at a frequency particular to only hydrogen

Figure 1. Nuclei under the influence of an external magnetic field
2. MRI Signal
• A Radio frequency pulse is applied and the nuclei flip through an angle of 90o
• The vectors begin to rotate in phase in the transverse plane
• the vectors induce a voltage in the receiver coil
• Different tissues produce different magnitudes of magnetic vector
• These are the MRI Signals

Figure 2. Nuclear Magnetic vector in the transverse plane

3. Contrast Generation
• High signal shows up as white
• Medium signal shows up as grey
• Low signal shows up as dark

4. Relaxation
• After a while they return to their former state and align with the magnetic field Bo
• Different tissues take different times to relalign with the magnetic field
• These differences enable a contrast difference between tissues

Factors that affect contrast

1. T1 Recovery
• The time it takes for 63.2% of the Nuclear Magnetic Vector to be realign with the longitudinal axis
• Caused by the dissipation of energy to the surrounding tissue
• Different tissues have different recovery rates
• T1 weighted images show anatomical detail

Figure 3. T1 Relaxation
.
2. T2 Decay
• During relaxation there is a loss in phase coherence of the Magnetic vector in the transverse plane
• It is the time it takes for the transverse magnetization to decay by 37%
• Fat has a short T2
• Water has a long T2
• T2 weighted images show pathology because of their high water content

Figure 4. T2 decay

3. Repetition time (TR)
• After a certain period the RF pulse is reapplied this is known as the TR

4. Echo time (TE)
• The time exhausted between the application of the RF pulse and when the coil receives the MRI signal

5. Flip angle
• The angle through which the NMV is flipped

Figure 5 Flip angle

6. Image Weighting
• The manipulation of parameters to produce images of predictable contrast is known as image weighting
• To demonstrate T1, T2 and proton density different values of
• TR controls the amount of T1 contrast (Fat has takes a short time to dephase and recover)
• TE controls the amount of T2 contrast (Water takes a long time to dephase in transverse plane)

7. T1 weighting
• Shows Fat signal bright
• Formed from a combination of
• Short TR : Fat recovers quickly,T1 is short for the NMV to be available to be flipped back into the transverse plane
• Short TE : Fat has a short T2 it dephases quickly from the transverse plane (MRI signal short0
• Water appears dark because its TR and TE are long and do not correspond to the T1 weighted parameters

8. T2 Weighted
• Shows water signal bright
• Formed from a combination of
• Long TR: Water takes a long time to recover, T1 is long for the NMV to be available to be flipped back
• Long TE : Water has long T2 it takes a long time to dephase in the transverse plane (MRI signal long)
• Fat appears dark because because the parameters do not correspond

Slice formation

• From the larmour equation the resonant frequency is proportional to the field strength applied
• By creating a linear change in the magnetic field the frequency will vary linearly along the length of the tunnel
• This is done with the use of gradient magnetic fields by gradient coils
• A known Radio frequency which corresponds with the position of the area of interest is applied
• Only the section with a similar frequency will receive excitation and produce a signal

Figure 5 Gradient

MRI in Hemorrhagic Stroke

Is the preferred imaging modality when a patient presents more than seven days after the symptom because at this stage it is more sensitive than CT
(DOH 2008 implementing best stroke strategy)

1. SAH
• MRI is less sensitive than CT in detecting Subarachnoid Haemorrhage in the first few days (A text book of radiology imaging pg 1769)
• The detection of a SAH clot depends on it yielding a higher signal than CSF. It can usually be detected after several days ( ibid pg1769)
• FLAIR is a more sensitive sequence used in order to suppress the CSF/protein content signal (Ibid 1679)

2. IPH
• Visible on the 3 – 4th day .
• Acute haematomas are hypointense on T2 weighted images because of the paramagnetic effect of deoxy haemoglobin ( ibid 1768)
• There is a high peripheral signal due to
- the break down of haemoglobin at the periphery
- The oxidation of deoxyhaemoglobin to metaemoglobin also in the peripheri
• Old intracerebral haemorrhages are represented by cysts associated with tissue atrophy(ibid 1768)

MRI pulse sequences

Examples of MRI pulse sequences used to show up strokes are

8.1 Perfusion Weighted images
• Perfusion is the delivery of blood to tissues
• Measured by suppressing the signal created by stationary blood molecules
• Increasing the signal intensity for dynamic molecules

8.1 Diffusion Weighted images
• Diffusion is the translational movement of water molecules in any direction
• Brain cells affected by stroke absorb a lot of water from extracellular space
• Diffusion becomes restricted
• Diffusion Imaging preserves the signal from stationary molecules
• Suppresses the signal from moving molecules
• This enables a contrast between pathological and non pathological cells

8.2 FLAIR Fluid Attenuated Inversion Recovery
• Designed to suppress the signal from Cerebrospinal fluid and show up clots

PROTOCOL SEIRES

1. AXIAL T2 WEIGHTED
2. AXIAL FLAIR
3. SAGGITAL T1 SPIN ECHO
4. DIFFUSION WEIGHTED
5. AXIAL T2# (GRADIENT ECHO) FOR TRAUMA
6. POST CONTRAST SEQUENCES SPIN ECHO T1
• AXIAL
• SAGITAL
• CORONAL
7. MRA CIRCLE OF WILLIS
8. PERFUSION SCAN POST PROCESSING CONTRAST

References
Figure 1. retrieved from
http://images.google.co.uk/imgres?imgurl=http://www.easymeasure.co.uk/webs/3/html/510/fig1.gif&imgrefurl=http://www.easymeasure.co.uk/principlesmri.aspx&usg=__8QtnXnDhXwL7yt0lGQmbRdFfuK8=&h=246&w=413&sz=11&hl=en&start=11&um=1&tbnid=ACdEZZp3Q9mc7M:&tbnh=74&tbnw=125&prev=/images%3Fq%3Drotating%2Bnuclei%2Bmagnetic%2Bvector%26hl%3Den%26sa%3DN%26um%3D1
Figures 2 – 4. Retrieved from

http://images.google.co.uk/imgres?imgurl=http://upload.wikimedia.org/wikibooks/en/d/d4/MagSumVector12.jpg&imgrefurl=http://en.wikibooks.org/wiki/Basic_Physics_of_Nuclear_Medicine/MRI_%26_Nuclear_Medicine&usg=__6yIVYSoesfHqMywJz_8rVvbnFyg=&h=315&w=555&sz=14&hl=en&start=3&um=1&tbnid=DY3ATxRX7Sc1sM:&tbnh=75&tbnw=133&prev=/images%3Fq%3Ddifferent%2Bnuclear%2Bmagnetic%2Bvectors%2Bin%2Btransverse%2Bplane%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-GB:official%26sa%3DG%26um%3D1
retrieved from wiki books

Figure 5 retrieved from
http://images.google.co.uk/imgres?imgurl=http://airto.hosted.ats.ucla.edu/BMCweb/BMC_BIOS/MarkCohen/Papers/RadidMRIPix/GRASSCycle.GIF&imgrefurl=http://airto.hosted.ats.ucla.edu/BMCweb/BMC_BIOS/MarkCohen/Papers/RapidMRI.html&usg=__eF93Fw7gy4Je93yfIE4SYlKWE2w=&h=236&w=283&sz=4&hl=en&start=6&um=1&tbnid=Q8EgbNXg5aZS6M:&tbnh=95&tbnw=114&prev=/images%3Fq%3Dmri%2Bsignals%2Bin%2Btransverse%2Bplane%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-GB:official%26sa%3DG%26um%3D1
Rapid MRI and applications from taveras et al radiology by mark cohen

Bibliography

WESTBROOK C, ROTH K and TALBOT J 2005 MRI in Practice, 3rd Ed Oxford Blackwell Publishing

WESTBROOK C 2002 MRI at A Glance, Oxford Blackwell Publishing

BALL J and MOORE A Essential Physics for Radiographers

SUTTON D, 2003 A Textbook of Radiology and Imaging, Churchill UK

MAGNETIC RESONANCE IMAGING

group2city — Sun, 05 Apr 2009 15:24:09 +0000

MRI Equipment

Patient table
• To securely hold and transport patient into the scanner

Electromagnet
• Series of wire coils through which voltage is passed to produce magnetic field
• To align the nuclei into their different energy states

Radio Frequency source
• To excite the nuclei and flip the magnetic vector

Radio frequency receiver coils
• Made to fit various body parts
• They receive MRI signals
• Head coil is used in the case of Stroke patients

Magnetic field gradient coils
• To determine the spatial location of signals

Image processor
• Processes signals by Fourier transformation to encoded computer language

Computer system
• Processes the information for display
• Serves as the operator interface to control the different processes

Figure 2. Nuclear Magnetic vector in the transverse plane

3. Contrast Generation
• High signal shows up as white
• Medium signal shows up as grey
• Low signal shows up as dark

Factors that affect contrast

Figure 4. T2 decay

3. Repetition time (TR)
• After a certain period the RF pulse is reapplied this is known as the TR

4. Echo time (TE)
• The time exhausted between the application of the RF pulse and when the coil receives the MRI signal

5. Flip angle
• The angle through which the NMV is flipped

Figure 5 Flip angle

Slice formation

Figure 5 Gradient

MRI in Hemorrhagic Stroke

Is the preferred imaging modality when a patient presents more than seven days after the symptom because at this stage it is more sensitive than CT
(DOH 2008 implementing best stroke strategy)

MRI pulse sequences

Examples of MRI pulse sequences used to show up strokes are

8.2 FLAIR Fluid Attenuated Inversion Recovery
• Designed to suppress the signal from Cerebrospinal fluid and show up clots

PROTOCOL SEIRES

Bibliography

WESTBROOK C, ROTH K and TALBOT J 2005 MRI in Practice, 3rd Ed Oxford Blackwell Publishing

WESTBROOK C 2002 MRI at A Glance, Oxford Blackwell Publishing

BALL J and MOORE A Essential Physics for Radiographers

SUTTON D, 2003 A Textbook of Radiology and Imaging, Churchill UK

COMPUTED TOMOGRAPHY (CT)

group2city — Sat, 28 Mar 2009 17:23:41 +0000

MAY & NAHILA….

CT Physics (Jackson / Thomas, 2005 & Gunn 2009 & Strang/Dogra 2007 & Seeram 2008)

Computed tomography (CT) uses a collimated X-ray beam to generate two dimensional transverse images of the patient. The image is composed of pixels (picture elements) in a 512 x 512 matrix.

Data Acquisition

Images are acquired by the rotation of an X-ray tube and detectors in a 360 degree arc around the patient. Scan time is the speed at which the gantry rotates once around the patient. A typical scan time for a multi-slice CT is less than 400 milliseconds.

Before the X-ray beam reaches the patient it goes through a ‘bowtie’ filter so that a monochromatic (uniform energy) beam of radiation is produced.

Some of the radiation is absorbed and scattered by the body and the rest is transmitted through the body.

The detectors measure the transmitted radiation; this has undergone differential attenuation whilst going through the body. The amount of attenuation depends on:-

- Effective atomic density of the material.

- Atomic number of the material.

- Photon energy in the X-ray beam.

Image Reconstruction

This data is digitised via an ADC and the resulting electronic signal is sent to the computer. This uses special image reconstruction (filtered back projection) algorithms (step by step procedures for solving a problem) to build up a digital CT image. Each pixel in the image represents the mean attenuation of a small box- like volume (voxel) through the thickness of tissue.

Image Display & Storage

The images are converted to a grayscale analogue image via an ADC. These can now be viewed on a CRT monitor or sent to other observers via PACS.

The images can be stored on magnetic tapes or discs.

Picture page 23 & 31 Jackson

Equipment

Every CT imager has four distinguishing components.

Operating station

· The operator uses this to set the scanning parameters and to view & manipulate the images.

Computer

· High capacity storage and fast processor to deal with the large volume of data that needs to be processed.

· May be built into the operating console.

Gantry

This houses the:-

· X-ray tube

· Detector array

· Collimator assembly

· High voltage generator

CT Table

· The table can be moved up & down and backwards & forwards to position the patient.

· Patient lies on the table which moves forward into the gantry at a controlled speed to allow the next ‘slice’ to be taken.

COMPUTED TOMOGRAPHY (CT)

ADVANTAGES

1. Excellent low contrast resolution due to:

- Highly collimated beam.

- More sensitive radiation detectors.

2. Window Width & Window Level settings can be adjusted to alter the contrast scale of the image to suit the observer.

3. The use of spiral/helical CT means that volume data can be acquired in a single breath rather than slice by slice. Gives better images especially in CT angiography & CT endoscopy.

4. CT used in a variety of diagnostic procedures:

Quantitative CT – determine bone mineral content.

Dynamic CT- study physiology.

SPECT/ CT & PET/CT fused images – study anatomy & physiology simultaneously.

5. Ideal for digital image processing.

6. 3D images.

LIMITATIONS

1. Low spatial resolution compared to MRI , nuclear medicine , ultrasonography.

2. High dose (radiation) procedure. Need comparison X-ray chest & CT Chest.

3. Hard to show anatomical region if area is surrounded by bone.

4. Metallic objects in patient cause streak artefacts.

DISORDER – LOCATION	RADIOGRAPHIC APPEARANCE
Intracerebral haemorrhage – haemorrhage into brain tissue	Non contrast CT- new haematoma appears as homogeneously dense, well defined, circular or oval lesions. These become isodense with time. Six months later haematoma appears as a well defined, low density lesion.
	MRI – high signal intensity on T1 & T2 weighted images. Later, a low signal intensity can be seen on T2 weighted images.
	CTA/MRA – shows aneurysms and arteriovenous malformations in large and medium blood vessels
	Arteriography – shows small blood vessels.

Subarachnoid haemorrhage- bleed beneath arachnoid layer of meninges	Non contrast CT- initially shows high attenuation of blood in subarachnoid space.
	MRI- T2 weighted images best for chronic haemorrhages, shown as hypointense areas.
	CTA- high resolution show aneurysms larger than 3mm.
	MRA – shows large and medium blood vessels for detecting an aneurysm.
	Arteriography –to demonstrate small vessel anatomy.

ULTRASOUND

group2city — Sat, 28 Mar 2009 17:22:54 +0000

Ultrasound

Ultrasound is best known for its role in obstetrics. Ultrasound can produce by dynamic and static images and during a Doppler investigation information can be displayed as a spectrum. Ultrasound is often the modality of choice for certain investigations as not only is it cheap and readily avaliable it does not employ ionising radiation therefore it is relatively safe although there is a risk of heating and damaging soft tissue organs. However if machine is programmed correctly this risk is kept to a minimum and does not result in a loss of image quality.

Equipment

Ultrasound scanners consist of a console containing a computer, a video display screen and a transducer that is used to scan the body and blood vessels.

Transducers:-

There are many types of Transducers such as the linear and the curvilinear then there are also intracavity transducers such as the transvirginal and transesophageal.

Higher Frequency = High Resolution = Low Penetration

Lower Frequency = Low Resolution = High Penetration

Ultrasound is a procedure that uses high-frequency sound waves, which are out of human hearing range, to view internal organs and produce images of the human body. The range of sound it usually uses 2.5MHz – 10 MHz. Ultrasound is relatively safe because it does not use ionizing radiation it does have some risk.

A probe its placed on to area of interest and moved around appropriately this produces an image on the monitor. Unlike electromagnetic radiation that can move through a vaccum, ultrasound uses mechanical energy that requires a medium to travel through this is while gel is used. Sound is transmitted through a transducer and then sound is received back to the transducer from the body part and is represented Each signal produces a dot that is either grey black or white it happens so quickly the human eye does not see the picture build up.

Bone = white

Fluid = Black

Soft Tissue = Grey

There are many reactions the sound can have within the human body and they are as follows:-

1. Reflection Sound goes in to the human body and reflects straight back, no penetration this usually happens in bone.

2. Scattering – The majority of structures within the human body are small and irregular in shape and give rise to scattering of the ultrasound beam

3. Refraction – this commonly happens when sound reaches the diaphragm. The direction of which the ultrasound pulse is travelling maybe refracted and change direction. We assume that sound travels in straight lines so if beam is refracted it will lead to artifact and misrepresentation on image.

4. Absorption No tissue is a perfect conductor of ultrasound and a high proportion of the energy is lost from the transmitted pulse because of absorption. Absorption occurs and no signal is transmitted back to transducer.

Ultrasounds role in a stroke

Ultrasound would not be a good modality to image the brain because of refection and a absorption. Ultrasound cannot pentrate bone sound is reflected straight back. Also the some of the beam is absorbed and the transducer does not receive any signal. Therefore only showing the outer surface of bony structures and not what lies within.

Although is not used in a haemorragic stroke. It can be used in prevention of an Ischemic stroke often if a patient is admitted with a TIA they will check the cause and this will mean imaging of the carotid arteries.

Examination

Transducer

High frequency linear (not alot of pentration need as arteries near surface)

Patient Position

Patient will be supine, with neck slightly extended and head turned away from side being examined.

Technique

Carotid arteries examined transversely. Followed by longitudinal scans.

Any plaque formation and its location extent and morphology (shape size etc) recorded. The degree of stenosis is quantified surgeons will usually operate if it is over 70%. Doppler analysis will also be carried out to check flow of blood. All findings will be recorded.

How this works – The transducer emits high-frequency, ultrasound waves that pass into the body and bounce off the carotid arteries and the red blood cells moving through them. The sound waves are reflected differently by different parts of the body. The transducer detects the different reflections of the sound waves, which are then measured and converted by a computer into live pictures of the arteries and the blood flow.

Echocardiogram or Transesophageal echodiography maybe used to produce images of the heart and located any blood clots.

Patient groups prone to strokes (epidemiology)

group2city — Fri, 13 Mar 2009 09:52:45 +0000

A stroke can happen to ANYONE at ANY age, with no obvious cause. But some factors are known to increase the likeihood of a person developing a stroke. These are the factors that can’t be changed ‘non modifiable’

Sex – For people aged under 75, more men have strokes than women.

Age – Strokes are more common in people aged over 55 and the risk continues with age.

Family History – Having a close relative who has had a stroke increases the risk. Hypertensin (high blood pressure) & diabetes tend to run in families.

Ethnic background- People from Asia, Africa & Afrrican – Carribbean communities are in the high risk group. They are more likely to suffer from hypertension & diabetes.

Taken from leaflet What is a stroke? (Stroke Association Association)

———————————————————-

Taken from Healthcare for London ( accessed through Royal College Physicians website)
Who is most at risk?

There are two main types of risk – which are known to doctors as ‘modifiable’ and ‘non-modifiable’.

Modifiable risks are those that can be reduced by people’s behaviour. For stroke, these risk factors include smoking, poor diet (including a high salt intake) and lack of exercise.

Strokes usually occur without warning, but many strokes are preventable, particularly if high blood pressure is monitored and controlled.

Simple steps can help reduce your risk of stroke:

stop smoking – smoking can double your risk of having a stroke
eat healthily – eat five portions of fruit and vegetables a day and reduce your salt intake
drink alcohol sensibly – drinking too much alcohol raises your blood pressure
exercise more – exercise helps lower your blood pressure
get your blood pressure checked

Non-modifiable risks include old age, socio-economic status, gender, ethnicity and genetic factors.

More than 75 per cent of strokes occur in people aged over 65. Black and Asian communities are more at risk – the number of strokes are 60 per cent higher amongst London’s African Caribbean population, compared with the white population – which given London’s diverse ethnicity, should make prevention an even greater priority for the capital.

——————————————————————————————————————————————————————————————————-

Epidemiology

Stroke is the third commonest cause of death in the developed world after ischaemic heart disease and all types of cancer combined.

Incidence of Stroke (Figures Stroke Organisation Association)

Every year an estimated 130 000 people in England and Wales have a stroke.

Most people affected are over 65, but anyone can have a stroke. Around 1 000 people per year are under 30 when they have a stroke.

More than 450 000 people in the UK live with disabilities caused by a stroke.

Stroke can be caused by:-

Thromboembolic infarction 69%

Cerebral haemorrhage 13%

Subarachnoid haemorrhage 6%

Unconfirmed 12%

Haemorrhagic strokes

Haemorrhagic strokes occur when a blood vessel in the brain bursts.

The main cause of cerebral haemorrhage is hypertensive vascular disease. High blood pressure (hypertension) can weaken the arteries in the brain and make them prone to split or rupture. They are usually located in the basal ganglia, white matter, thalamus, cerebral hemispheres and pons.

The risk factors for high blood pressure include:

· being overweight,

· drinking excessive amounts of alcohol,

· smoking,

· a lack of exercise, and

· stress which may cause a temporary rise in blood pressure.

A person’s ethnic group can also be a risk factor for high blood pressure. African-Caribbean people are twice as likely to have a stroke (compared to Caucasian people) as this group generally have particularly high rates of blood pressure.

Cerebral haemorrhages can also be caused by head trauma and less frequently by the rupture of congenital berry aneurysm or arteriovenous malformation.

Subarachnoid haemorrhages are generally caused by the rupture of a berry aneurysm. Most commonly found in the origins of the posterior cerebral and anterior communicating arteries and the trifurcation of the middle cerebral artery.

Definitions (below) in notes

Aneurysm – bulge in artery that weakens the wall

Arteriovenous malformation (AVM) – where the arteries & veins are not built as strongly as regular blood vessels and have a greater tendency to bleed.

Reducing risk of haemorrhagic stroke

Risk Factor	Intervention	Cerebral haemorrhage	Subarachnoidhaemorrhage
Hypertension	Treat	Major correlation	Possible
Smoking	Stop	Moderate correlation	Probable
Atrial fibrilation	Anticoagulate	Possibly increase risk	None/Not proven
Obesity	Weight reduction	Probable	None/Not proven
Diabetes	Good control	None/Not proven	None/Not proven

(Kumar & Clark, 2005)

Atrial fibrillation is type irregular heart rhythm

Hypertension >140/90 mmHg

Obesity BMI > 30

Complications of strokes

group2city — Tue, 10 Mar 2009 00:09:04 +0000

Okay so these are a bit obvious but a list i found… if you want me to look more closely at a specific complication we can decide here or at the next meeting. [copied and pasted from this site http://www.wrongdiagnosis.com/s/stroke/complic.htm#complication_list]

General Complications
Paralysis
Coma
Death
Hemiparesis
Vision problems
Speech problems
Recurrent strokes (see Stroke symptoms)
Cognitive deficits
Emotional difficulties
Daily living problems
Pain

Complications of a right hemisphere stroke:
Left hemiplegia (see Hemiparesis)
Spatial problems
Perception problems
Impaired judgment (see Cognitive impairment)
Behavior problems
Short-term memory problems (see Forgetfulness)

Complications of a left hemisphere stroke:
Right hemiplegia (see Hemiparesis)
Aphasia
Speech problems
Language problems
Slowness (see Movement symptoms)
Cautious behavior
Short-term memory problems (see Forgetfulness)

Complications of a cerebellar stroke (see Stroke symptoms)
Abnormal head reflexes (see Reflex symptoms)
Abnormal torso reflexes (see Reflex symptoms)
Coordination problems
Balance problems (see Dizziness)
Dizziness
Nausea
Vomiting

Complications of a brain stem stroke (see Stroke symptoms)
One-sided paralysis (see Hemiparesis)
Two-sided paralysis (see Paralysis symptoms)
Breathing difficulty
Blood pressure problems (see Blood pressure symptoms)
Heart problems
Eye movement problems
Hearing problems
Speech problems
Swallowing problems

Patient groups prone to strokes (epidemiology)

group2city — Tue, 10 Mar 2009 00:07:16 +0000

Causes & Symptons (aetiology)

group2city — Mon, 09 Mar 2009 23:52:48 +0000

Please feel free to add onto what i have found using the information that May had provided us with and with the daily telegraph book that i had.

symptoms of a stroke:

weakness/ numbness of the face, arm, leg
loss or slurring of speech
loss or blurring of vision
sensation of motion
difficulty with balance
vomiting
severe neck stiffness, this is not present within 24 hours
rapid loss of consciousness

Causes:

trauma
rupture of congential intracranial aneurysm
blood dyscrasia
arterious malformation

Nahila

Patient Pathway

group2city — Mon, 09 Mar 2009 23:51:37 +0000

1. The will be admitted to hospital via A & E or their GP.

2. Blood pressure is taken the most common cause of a stroke is hypertension Blood samples are taken to check:- Chloresterol Levels Clotting levels Blood sugar Level Can determine cause and if treatment drugs will cause damage to liver and kidneys.

3.A neurological assessment will be carried out (guys struggling to find out what a doctor will actually do here so any help will be

4. A Stroke Patient will need to have a Brain scan as soon as possible to determine should be within 24 hours. Some patients should have within the hour if :-

there is an indication for thrombolysis/anticoagulation,

Depressed level of consciousness

Unexplained Fluctuating or progressive symptoms

Severe Headache at onset

Papilloedema, Neck, stiffness, fever

Scan is to determine:-

• The type of stroke Ischemic or Hemorrhagic.

• Which part of the brain has been effected.

• How severe the stroke is

The brain scan will be either CT or MRI depending on the patient… didn’t want to get to deep into this as thought we would go into detail later Time is crucial MRI takes long then CT.

5.Swallow Tests are essential for anyone who has had a stroke as swallowing problems effect over a third of people that have a stroke. There is a risk of aspiration.

6.Heart and Blood Vessel Tests Further tests on the heart and blood vessels might be carried out later to confirm what caused the stoke such as:

Ateriography (ct/mri/fluorsocopy)

Echocardiogram – Also Transesophageal Echocardiography

Physical Examination – doctor maybe check blood pressure and using a stethoscope listen to the sound of the blood in the neck arteries.

7.Treatment Treatment will dependent on the type of stroke

Initial treatment: Oxygen will be given, fluids through IV has people who have had a stroke will be dehydrated, Blood pressure control usually medication will be give to lower blood pressure but not too low as the brain need to still get enought blood.

The treatment for Haemorrhagic Stroke is quite different to Ischaemic Stroke: For small bleeds, they are often watched and allowed to heal on their own.

In the case of a large bleed or if the Stroke extends or appears to be getting worse, surgery may be done to ‘decompress’ the brain release the blood which has built up, causing swelling. This takes up space in your brain squeezing it against the skull. Surgery is undertaken to drain or remove blood in or around the brain that was caused by a bleeding blood vessel.

A Haemorrhagic Stroke may be caused by a brain aneurysm. If this occurs a surgeon may perform endovascular coil embolisation to repair the weak artery. A small coil is inserted into the aneurysm to block it off. The location of the aneurysm, its size and your general health are used to determine if the surgery can be performed.

An arteriovenous malformation is a congenital disorder that causes an abnormal web of blood vessels and veins in the brain, brain stem, or spinal cord. The vessel walls of an arteriovenous malformation may become weak and leak or rupture. Surgery may repair abnormally formed blood vessels (arteriovenous malformations) that have caused bleeding in the brain.

8. Patient rehabilitation will be different for every patient as the stroke can effect different parts of the Brain:

Cerebrum – (70% of CNS)

Serves higher mental functions

Regulates sensorimotor integration

Relates Perception with experiences

Basically receives information from all over the body compares it with previously stored information and decides whether any action needs to be taken and the sends signals to muscles causing them to perform appropriate action.

There are to halves separated by the falx cerebri

Rt Hemisphere – Controls the left side of the body. Emotion and one sense of postion in space if damage may not feel that their body is their own.

Left side control right side of body seen as more logical side. Deals with analytical thought, problem solving and language. If damages may causes problems with speech and understanding.

Cerebrum has four lobes

Occipital Lobe –Sight

Temporal Lobe Hearing and Olfaction within the left temporal lobe there is Wernickes area = ones understanding of speech. Also is the area that stores ones memories. Luckily if only one lobe is damaged not all memory is lost as other parts of the brain will be able to make up for the damage.

Parietal Lobe –Touch and taste

Frontal Lobe Shape behavior/anticipation/emotion/thinking. Motor function for planning and expression of language. Boca’s area is within this lobe which is the centre for speech expression.

Definition of Haemorragic stroke

group2city — Mon, 09 Mar 2009 18:30:32 +0000

1. A stroke is a clinical syndrome characterised by rapidly developing clinical symtoms and/or signs of focal, and at times global (applied to patients in deep coma and those with subarachnoid haemorrage), loss of cerebral function, with symptoms lasting more than 24 hours or leading to death with no apparent cause other than that of vascular origin (Hatano S 1976)

A stroke is a brain attack. It happens when the blood supply to the brain is disrupted. There are two types of stroke

i) Ischaemic: Blood clot blocks the flow of blood to the brain

ii) Haemorrhagic: Bleeding in or around the brain from a burst blood vessel.

In both cases the brain is starved of oxygen (Hypoxia) causing tissue damage or death. Sufferers are often left with difficulty talking, walking and performing other basic tasks.
(DOH)

There are two types of Haemorragic Stroke

1. Subarachnoid Haemerrahge

This is when the blood from the haemorrage spreads through the subarachnoid space and mixes with blood causing the intercranial pressure to increase.

2. Cerebral Haemorrhage

This is when blood from the haemorrhage accumulates in the cerebrum to form a haematoma.