CNS Part 1 And 2 Flashcards
What does the CNS contain?
The brain and spinal cord
It is responsible for generating thoughts and emotions, memories are formed and stored, and connects the body via cranial and spinal nerves to stimulate muscle contraction and gland secretion.
How many neurons does the adult brain have?
100 billion neurons
The brain weighs about 3 pounds and is somewhat shaped like a mushroom.
How many main parts can the brain be divided into?
4 main parts
Cerebrum, cerebellum, diencephalon, and brain stem.
What are neurons?
The fundamental units of the nervous system
Involved with the movement of Na, Ca, K ions across cell membranes. Neurons are responsible for impulses in the body, including motor neurons that tell muscles to move and sensory neurons that allow you to feel sensations.
Nerve impulses speed
Nerve impulses can travel from 1-280 mph
Means that your brains can work @ 280 mph
Cerebrum
Cerebrum is the bulk of the brain
This is your memory, intelligence, ability to read, write, speak and do calculations
Cerebral cortex
The surface is composed of gray matter
The gray matter is called cerebral cortex. The cerebral cortex contains your neurons
White matter
Beneath the cerebral cortex lies white matter
White matter contains nerve tracts
Cerebrum structure
The cerebrum is made up of 2 hemispheres and 4 lobes
The 2 hemispheres are connected by the corpus callosum. The 4 lobes are: Frontal, Temporal, Parietal, Occipital
Frontal lobe
Higher mental activities: Planning, judgment, personality and speech
Temporal lobe
Hearing languages, memory, and learning
Parietal lobe
Sensory function
Occipital lobe
Vision
What is the cerebellum shaped like?
The cerebellum is shaped like a butterfly
Example: The cerebellum is often described as resembling a butterfly in shape.
What does the cerebellum control?
The cerebellum controls the movement of skeletal muscles
Alcohol affects your cerebellum.
What does the cerebellum help with?
The cerebellum helps with your sense of equilibrium, coordination, and balance
The anatomy of the cerebellum is similar to the cerebrum.
Where is the cerebellum located?
The cerebellum is located in the inferior and posterior portion of the brain
Gray matter is on the outside (outer) and underneath white matter.
What does the diencephalon contain?
The diencephalon contains the thalamus and hypothalamus
Thalamus - majority of the diencephalon
What is the thalamus responsible for?
The thalamus relays sensory impulses to other parts of the brain and is responsible for the sensation of pain and temperatures
Consists mainly of gray matter.
What functions does the hypothalamus control?
The hypothalamus controls autonomic functions such as body temperature, water balance, pituitary function, hunger, and emotions
Picks up impulses such as sound, taste, and smell.
What are the components of the brain stem?
The brain stem consists of the medulla, pons, and midbrain.
Example sentence: The brain stem is responsible for controlling many basic life functions.
What is the function of the medulla?
The medulla contains tracts that connect the spinal cord to the brain, and is involved in motor function, cardiovascular control, and respiratory regulation.
Example sentence: Damage to the medulla can result in serious breathing problems.
What is the function of the pons?
The pons contains tracts that connect the spinal cord to the brain and other parts of the brain, and helps the medulla with respiration.
Example sentence: The pons plays a crucial role in coordinating breathing patterns.
What is the function of the midbrain?
The midbrain has tracts that connect the upper and lower parts of the brain, and contains reflex centers for the eyes, head, and neck to respond to visual and other stimuli.
Example sentence: The midbrain is important for processing visual information and coordinating reflex movements.
How many stacked bony vertebrae are in the vertebral column?
The vertebral column contains 25 stacked bony vertebrae.
Example sentence: The vertebral column provides structural support and protection for the spinal cord.
How many cervical nerves are in each vertebra?
Each vertebra has 8 cervical nerves.
Example sentence: The cervical nerves control movement and sensation in the neck and upper limbs.
How many thoracic nerves are in each vertebra?
Each vertebra has 12 thoracic nerves.
Example sentence: The thoracic nerves innervate the chest and abdominal regions.
How many lumbar nerves are in each vertebra?
Each vertebra has 5 lumbar nerves.
Example sentence: The lumbar nerves control movement and sensation in the lower back and legs.
What is the function of the sacrum?
The sacrum has 5 bones and 5 pairs of nerves.
Example sentence: The sacrum connects the spine to the pelvis and supports the weight of the upper body.
What is the function of the coccyx?
The coccyx has 1 bone and 1 pair of nerves.
Example sentence: The coccyx is commonly referred to as the tailbone and provides attachment for muscles and ligaments.
What structure runs in the middle of the vertebral column?
Spinal cord
The spinal cord runs in the middle of the vertebral column
Where does the spinal cord extend to?
T-12
It extends to T-12
Where is a spinal tap usually performed?
Between L-2 and L-3
A spinal tap will be performed between L-2 and L-3 usually to make sure you don’t nick the spinal cord
What is the spinal cord the main highway for?
Nerve impulse conduction
It’s the main highway for nerve impulse conduction
What does the ventricular system consist of?
Cavities within the brain that produce cerebral Spinal Fluid (CSF)
The ventricular system consist of cavities within the brain that produce cerebral Spinal Fluid (CSF)
What are the cavities within the brain that produce CSF called?
Ventricles
The cavities are called ventricles
How many ventricles are there within the brain?
4 ventricles
There are 4 ventricles within the brain
What secretes CSF in each ventricle?
Choroid Plexus
The choroid Plexus of each ventricle secretes CSF
What is CSF?
CSF is a clear colorless fluid.
CSF circulates through sub-arachnoid spaces around the brain.
What are the functions of CSF in the brain?
CSF protects the brain from shock, delivers nutritive substances (like gloucose proteins), and removes waste (lactic acid + urea)
What is the normal ventricular system volume of CSF?
The whole system contains between 80 - 150 ml of CSF. It’s produced at a rate of 20ml/hr.
How is CSF pressure measured?
CSF in the ventricular system produces a pressure of 50-180 mm H2o. Similar to blood pressure but remains fairly constant.
How is CSF reabsorbed back into the body?
Reabsorption takes place in the Arachnoid Villi. CSF should be reabsorbed at the same rate it is produced.
What is a Lumbar puncture (Spinal Tap)?
Method used to insert a needle into the spinal cavity. Pressure of CSF can be determined and a sample can be taken.
What is the composition of the brain in terms of body weight?
The brain composes of 2% of body weight
However it consumes 20% of oxygen in the body at rest (brain needs a lot of oxygen)
What is the majority of blood vessels that enter the brain?
The majority of blood vessels that enter the brain form the cerebral arterial circle. (Circle of Willis)
What does the brain use as its main nutrient for energy?
The brain uses glucose as its main nutrient for energy
What determines the amount of oxygen and glucose needed by the brain?
The degree of mental activity determines the amount of oxygen and glucose
What does the Blood Brain Barrier (BBB) act like?
The BBB acts like a filter to keep certain substances out of the brain
What does the BBB do to protect brain cells?
Functions to protect the brain cells from harmful substances and pathogens
What is one difficulty associated with the BBB?
However, it makes it difficult for medicines to enter the brain
It’s hard to treat brain disorders
What is the composition of the brain in terms of body weight?
The brain composes of 2% of body weight
However it consumes 20% of oxygen in the body at rest (brain needs a lot of oxygen)
What is the majority of blood vessels that enter the brain?
The majority of blood vessels that enter the brain form the cerebral arterial circle. (Circle of Willis)
What does the brain use as its main nutrient for energy?
The brain uses glucose as its main nutrient for energy
What determines the amount of oxygen and glucose needed by the brain?
The degree of mental activity determines the amount of oxygen and glucose
What does the Blood Brain Barrier (BBB) act like?
The BBB acts like a filter to keep certain substances out of the brain
What does the BBB do to protect brain cells?
Functions to protect the brain cells from harmful substances and pathogens
What is one difficulty associated with the BBB?
However, it makes it difficult for medicines to enter the brain
It’s hard to treat brain disorders
What happens if the blood brain barrier becomes injured?
It can be altered or broken down.
Substances that normally do not pass, can breach the barrier. Toxins may enter the brain. This could be due to trauma, inflammation, or toxins.
What are some studies being done related to the blood brain barrier?
Studies are being done to breach the barrier to allow certain drugs to enter the brain. This can help in the treatment of the brain.
No example sentence provided.
What is a Cerebrovascular Accident (CVA)?
It is a stroke when there is a compromised blood supply to the brain for ≥ 24 hrs.
No example sentence provided.
What are the two principle types of CVA’s?
Ischemia - decreased blood supply (due to blockage).
Hemorrhage - rupture of blood vessel.
No example sentence provided.
What are some symptoms of CVA?
Dizzy, weak, numb, paralysis, drooping of side of the face, headache or slurred speech.
No example sentence provided.
What are some causes of CVA?
Intracerebral hemorrhage, emboli, atherosclerosis, compression of a tumor on a blood vessel.
No example sentence provided.
What are some risk factors for CVA?
High BP, high cholesterol, TIA, diabetes, smoking, obesity, alcohol, family history, or age.
No example sentence provided.
What can PET + SPECT determine at the onset of a stroke?
Perfusion defects
Show blood flow and metabolic abnormalities
What do CT + MRI show in relation to strokes?
Anatomic lesions
There has to be anatomic changes to show a CVA
What is a possible treatment for a stroke?
Medications that dissolve blood clots or prevent new ones from forming
A surgery to remove blood clots, prevent bicecling or, in some cases, to re-open the blocked arteries
Endarterectomy - surgery done to remove a clot or plaque
A rehabilitation program at a social facility or in the patient’s home to help recovery
What is a Transient Ischemic Attack (TIA)?
A temporary impaired blood supply to the brain for less than 24 hrs
TIA usually subsides within a few mins to hours
What are some symptoms of a TIA?
Dizzy, weak, numb, paralysis, drooping of one side of face, headache and slurred speech
Causes of transient ischemic attack (TIA)
Most are caused from atherosclerosis or emboli
Example sentence: A TIA can be caused by a blood clot traveling to the brain.
Risk factors for TIA
Same as stroke
Example sentence: High blood pressure and smoking are common risk factors for both TIA and stroke.
Percentage of TIA patients who will have a stroke within 5 years
43%
Example sentence: Nearly half of patients who experience a TIA will go on to have a stroke within 5 years.
Alzheimer’s Disease
A disabling neurological disorder affecting 11% of the population over the age of 65
Symptoms are characterized by loss of memory and cognitive skills.
Causes of Alzheimer’s Disease
Unknown
There is currently no known cause for Alzheimer’s Disease.
Treatment for Alzheimer’s Disease
No cure, but drugs can help contain it and slow down progression
Effects of Alzheimer’s Disease are irreversible.
Cerebral Palsy
A motor disorder resulting in muscular incoordination
There is damage to motor areas of the brain.
Causes of Cerebral Palsy
Lack of oxygen during birth, hydrocephalus
Cerebral Palsy usually occurs before or during birth.
Treatment for Cerebral Palsy
No cure, but training and therapy can help improve function
Example sentence: Physical therapy and occupational therapy can help individuals with Cerebral Palsy lead more independent lives.
Causes of transient ischemic attack (TIA)
Most are caused from atherosclerosis or emboli
Example sentence: A TIA can be caused by a blood clot traveling to the brain.
Risk factors for TIA
Same as stroke
Example sentence: High blood pressure and smoking are common risk factors for both TIA and stroke.
Percentage of TIA patients who will have a stroke within 5 years
43%
Example sentence: Nearly half of patients who experience a TIA will go on to have a stroke within 5 years.
Alzheimer’s Disease
A disabling neurological disorder affecting 11% of the population over the age of 65
Symptoms are characterized by loss of memory and cognitive skills.
Causes of Alzheimer’s Disease
Unknown
There is currently no known cause for Alzheimer’s Disease.
Treatment for Alzheimer’s Disease
No cure, but drugs can help contain it and slow down progression
Effects of Alzheimer’s Disease are irreversible.
Cerebral Palsy
A motor disorder resulting in muscular incoordination
There is damage to motor areas of the brain.
Causes of Cerebral Palsy
Lack of oxygen during birth, hydrocephalus
Cerebral Palsy usually occurs before or during birth.
Treatment for Cerebral Palsy
No cure, but training and therapy can help improve function
Example sentence: Physical therapy and occupational therapy can help individuals with Cerebral Palsy lead more independent lives.
What is epilepsy?
Is a neurological disorder it effects 1 out of 100 people
Epilepsy causes sudden, uncontrollable electrical surges in the brain.
What are the effects of epilepsy?
Effects - seizures, brief interruptions in brain activity, periods of unawareness, may involve changes of consciousness, involuntary movement, muscle spasms or convulsions.
Treatment for epilepsy includes medications, special diets, or surgery.
What can cause epilepsy?
Epilepsy can be caused by head trauma, infection, neurological disorders, and hereditary factors. People cannot swallow their tongues as epilepsy is not contagious.
What is Parkinson’s Disease?
Is a progressive disorder of the CNS. Certain neurons are destroyed in the brain, which produce dopamine. An imbalance of neurotransmitter activity occurs.
The cause of Parkinson’s is unknown, but a defective gene has been found in some cases.
What is hydrocephalus?
Occurs when fluid spaces in the brain are enlarged
The fluid spaces are the ventricles
What are the 3 types of hydrocephalus?
- Communicating - CSF inside the ventricles ‘communicates’ or is open to the fluid spaces around the brain
- Non-communicating - obstruction in a ventricle
- Normal Pressure Hydrocephalus (NPH) - enlargement of a ventricle without increased pressure
What causes communicating hydrocephalus?
CSF flows normally throughout the CNS but is not being reabsorbed
Causes build up in the ventricles
Usually caused by an infection (meningitis) that forms an obstruction
Can be treated with a shunt
Usually caused by an infection (meningitis) that forms an obstruction
What causes non-communicating hydrocephalus?
CSF can’t ‘communicate’ outside the ventricle
CSF builds up within the ventricle
The ventricle doesn’t expand and pressure of CSF increases (usually caused by a tumor)
Usually caused by a tumor
What is Normal Pressure Hydrocephalus (NPH)?
Enlargement of a ventricle without increased pressure
CSF within a ventricle increases
Normal Pressure Hydrocephalus (NPH) causes:
Could be due to reabsorption problem or blockage with increased CSF the ventricles expanding, the ventricle expands the pressure of the CSF remains normal
What are the main reasons for the decrease in Nuclear Medicine imaging of the brain?
Mainly due to the availability of CT + MRI
This answer highlights that the availability of CT and MRI has led to a decrease in Nuclear Medicine imaging of the brain.
In what instances can Nuclear Medicine imaging be used for the brain?
Function and perfusion of cerebral abnormalities
CSF imaging
Nuclear Medicine imaging can be used for assessing function and perfusion of cerebral abnormalities, as well as for CSF imaging.
What are the two groups into which brain imaging can be divided?
Planar Brain Imaging & SPECT Brain Imaging
Brain imaging can be divided into Planar Brain Imaging and SPECT Brain Imaging.
What is an important characteristic of radiopharmaceuticals used in planar brain imaging?
They do not cross a normal (intact) BBB
Radiopharmaceuticals used in planar brain imaging do not cross a normal (intact) BBB.
Where does 99mTc accumulate in the brain?
99mTc accumulates in the choroid plexus of the brain
99mTc accumulates in the choroid plexus of the brain, making imaging difficult in some situations.
What can be administered to block the accumulation of 99mTc in the choroid plexus of the brain?
Oral Potassium Perchlorate
Oral Potassium Perchlorate can be administered to block the accumulation of 99mTc in the choroid plexus of the brain.
When should Tc-99m DTPA be given before a brain scan?
30-60 minutes before the scan
Example sentence: Dose 15-25 mCi of Tc-99m DTPA in a brain scan by injection
What is the imaging time range for Tc-99m DTPA?
0-4 hours, with 0 hours being for flow and 4 hours for brain lesions
Does Tc-99m DTPA cross the BBB?
Does not cross the BBB
Example sentence: Dose of 15-20 mCi of Tc-99m DTPA will allow us to image at 0-60 minutes
What is the target/nontarget ratio of Tc-99m DTPA?
Good target/nontarget ratio
Reasons: - Tc-99m DTPA clears the blood and into the brain rapidly - Tc-99mDTPA will also leave the body via urine quickly
What is the dose range for Tc-99m Gluconsptonate (GH) and the imaging time range?
Dose of 10-20 mCi, and image from 0-4 hours
Example sentence: Going out 4 hours gives more time for accumulation in tumors
What do 99mTc Radiopharmaceuticals have in common?
They all use 99mTc
Good for perfusion
Give similar imaging results
Give higher doses
What are the differences between DTPA + GH
GH are more expensive
They are all good for flow studies but the time it takes for them to localize and allow for delayed images is different.
DTPA is the quickest -0-60 mins
Then GH -0-4 hours like regular Tc
Finally Tc-99m
What are the characteristics of Thallium-201?
Dose - 2-3 mCi
Imaging time - 0-60 mins.
Not especially good for flow studies but localizes fairly well in METS
Example sentence: Thallium-201 is commonly used for myocardial perfusion imaging.
Ga localization
Localizes in inflammatory and infectious areas
Ga dose
Dose - 3-6mCi
No additional information
Ga imaging timing
Imaging - 24-72 hrs
No additional information
99mTc- Phosphate’s (MDP + HDP)
Good for differentiating cerebral infarcts
Dose:15-20 mCi
Imaging :0-4 hours
Indications to use RP : 67 Ga/99mTc
Evaluate Brain: Perfusion, Brain Death, Evaluate stroke (CVA)
Planar Brain Imaging
RP→ Depends on the indications
There is:
Patient Prep → No Prep for these studies
Evaluate Localization of RP
Metastatic brain tumors
Cerebral infection
Cerebral inflammation
Evaluate Localization of RP
Metastatic brain tumors
Cerebral infection
Cerebral inflammation
What is the first step in Procedure Prep?
To keep brain function normal (not over-functioning)
Always use an IV and start the IV at least 20 min pre-injection. Have patient lie supine and still for at least 20 min pre-injection.
What should be done in the Imaging room for Procedure Prep?
The Imaging room should be quiet and dimly lit. Keep the patient calm and still for at least 20 min pre-injection.
This helps in maintaining normal brain function.
What does the Procedure consist of?
The Procedure consists of 2 phases: A dynamic study of rapid sequential images (Flow Study) and Immediate brain perfusion. Measures Regional Cerebral blood Flow. Delayed static images taken when the activity settles in the brain. Represents the distribution of the activity in the cerebral regions.
Usually 1-4 hours when using Tc based tracers.
Flow Images
Patient should be positioned supine
Head strap may be used if necessary
Camera positioning
Camera is usually positioned for an ANT image.
A bolus injection of 15-20 mci of imaging agent
Injection technique
Use the oldendorf technique for your injection
Timing of images for Flow Images
2-3 second images are obtained for 60 seconds
Delayed Images
Patient is again supine and should remain as still as possible
Static images will start 20-60mins post injection
Duration of Static Images
Static images can be taken out to 3-4 hours using the same agent
Count for Images
Images will be taken for 500,000 counts
ANT, POST, R, +L LAT
Consistency in counts and views
Remain consistent with your counts and views if delays at different times are taken
Brain Death
Determines if any blood flow is going to the brain
Positive flow will show tracer in the carotids, but nothing in the cerebral arteries
Positive delay images will continue to not show activity in the brain
A positive scan will show some extracerebral activity
Primary Brain Tumor
Will show as a single focus of activity
May or may not show on the flow
Depends on the blood flow to the tumor
Should show on delays
Depends on the rate of blood flow
Metastases
Usually shows as multiple small focal hot spots
Will show on flow and delayed views depending on blood flow to the METS
Cerebrovascular Disease
Will show an asymmetric flow (uneven)
Delays will show a wedge-shaped defect
Inflammation or infection
Focal area of increased uptake with an area of decreased activity in the center
Called a Doughnut sign
What are radiopharmaceuticals used for in SPECT brain imaging?
Rp used for SPECT imaging cross the BBB
BBB stands for blood-brain barrier.
How do radiopharmaceuticals enter the brain in SPECT imaging?
They actually enter the brain substances
No additional information provided.
Where do radiopharmaceuticals remain in the brain in proportion to?
They remain in the brain in proportion to the regional cerebral blood flow
Cerebral blood flow is abbreviated as CBF.
Tc-99m HMPAO(Ceretec or exametazime) *The good
The good: this agent also has rapid first pass uptake
- The use of 99mTc enables a 20 mCi dose and is great for SPECT dose
-Once it is the brain it will not diffuse out it will remain until it decays
Tc-99m HMPAO (Ceretec or exametaazime) * The Bad
Unstable in-vitro( outside the body)
Should be injected 30 mins after preparation
____ is currently the RP of choice but there is another one dose on its tail
Ceretec
Tc-99m ECD(Neurolite or Biscate) The Good:
More rapid clearance of the blood pool than Ceretec
Reducing background activity
Increasing target to non target ratio
More stable than ceretec
Longer post injection time
Xe-133 is also good for brain imaging
It can be inhaled or dissolved in saline and injected either way it goes into the blood stream and goes to the brain.
-It localizes quickly in the brain and then washes out quickly allows us to measure rCBF
Doses for Xe-133
1-10 mCi which is an average dose for SPECT the low energy of Xe-133 creates limitation for detection especially behind the skull.
Sagittal
Cut Right to Left
Coronal
Cut from front to back
Transverse
Cut from top to bottom
SPECT Brain Imaging Indications
Evaluate Cerebravascular disease( infraction hemorrhage TIA’s)
Evaluate dementia
Evaluate trauma
Locate seizure foci
SPECT Brain Imaging Patient Prep
No patient prep
SPECT Imaging Dose
Inject 20 mCi of 99mTc brain agent IV
The flow is optional-Inject a bonus if a flow is desired
SPECT images can be obtained 20 mins post injection with a 360 degree rotation
Then data is reconstructed to give Transverse/Coronal/Sagittal
SPECT Brain Clinical Applications - Normal
Crosses the BBB and localizas proportional to blood flow
More blood to gray matter of the brain
SPECT Brain Clinical Applications - Brain Death
Same principle as planar imaging
A little more sensitive than planar imaging
SPECT is not as dependant on the flow study
SPECT Brain Clinical Applications - Brain Tumor
Localize a focal defect in both primary and metastatic lesions
Using same Tc-agents
SPECT Brain Clinical Applications - Infarction
Will show as a reduced or no blood supply to a particular area
SPECT Brain Clinical Applications - TIA
Temporary hypoperfusion defect
TA defects are time dependent
The longer you wait, the less sensitive the scan is to detect the effects of a TA
Will show as a reduced blood supply to a particular area.
What should a normal SPECT brain look like?
Bilaterally symmetrical activity on the SPECT images
• Activity is also high in the regions corresponding to the basal ganglia and thalamus
• Regions between the basal ganglia and thalamus
• Regions between the basal ganglia and the convexity corresponding anatomically to cortical white matter and the ventricles have less activity
• SPECT images can be seen in a number of different color scales
What does CSF imaging involve?
CSF runs around the brain and down the spinal column
We can image the fluid pattern in this system as well
• CSF imaging
• Cisternogram
Cerebral Spinal Fluid Imaging
What is the most widely used radiopharmaceutical for CSF imaging?
In-111 DTPA
It has a longer half-life of 2.8 days images are commonly taken up to 72 hours, has abundant gamma emissions, mixes well, and has a good affinity for CSF.
What are the indications for CSF imaging procedure?
Diagnose normal pressure hydrocephalus (NPH), identify CSF leaks, verify CSF shunt patency.
How is In-111 DTPA administered for CSF imaging?
0.5 - 1.0 mCi injected intrathecally (lumbar). Indium-111 DTPA can be used for shunt patency.
Who typically performs the injections for CSF imaging?
Injections are done by the doctor, usually the radiologist or neurologist.
Is patient prep necessary for CSF imaging?
No patient prep is necessary.
CSF Imaging Procedure
Procedure with the patient laying on their side, the doctor will inject intrathecal
22 gauge or smaller needle is recommended to minimize leaks
Injection Location
Injection will be between the vertebrae L-2 or lower, and will go into the subarachnoid space
The patient needs to stay horizontal for 2 hours post injection. Pt movement can initiate headaches
Image Acquisition
Images will be taken @ 2, 6, 24, 48, 72 hours if necessary. An initial image can be taken POST to verify the injection site
Patient will be positioned supine for the images. Images will be acquired for 100k to 200k counts.
Noncommunicating Hydrocephalus
Since In-DTPA is mixed in with CSF, it should not normally flow in the ventricles. We cannot diagnose this using a lumbar puncture. However, if you must use In-DTPA, you can inject it directly into the ventricles. Not very common.
Example sentence: Sounds painful but it has been done.
CSF Leaks
We can localize the site of the leak. Plugs can be placed in the nose or ears. This is a common spot for leaks. Then count the plugs. If activity shows up, there is your leak. This method is not very common either.
Additional information: This metrod is not very common either.
Abnormal Radiopharmaceutical Flow
Shunt Patency. A shunt will drain CSF from the brain into other areas. By injecting into the shunt, we can watch the flow of the RP. An open shunt will show activity draining. An obstructed shunt will show retention of the tracer. Remember we can use 99mTc-DTPA due to the short duration of the study. 1-3 mCi given. 99mTc-DTPA. Can also be used 500 uCi of In-DTPA
CSF RP Flow
-RP will ascend up the spinal column
-At 2-4 hours the RP should be in the basal cisterns
-From 6-24 hours the ascent of In-111-DTPA will continue up the Sylvia’s and interhemispheric fissures
-Activity will start into subdrachoid spaces (cerebral convexities)
-At 24 hours there should be complete ascent of the RP over the cerebral convexities
And some if not all activity will clear from the cisterns
-48 hours the RP should appear as a cap as it is completely filled into the sinuses
-When In-111 DTPA doesn’t follow the normal pattern different clinical applications may apply
Normal Pressure Hydrocephalus
-111-In-DTPA should not enter lateral ventricles by 4-6 hours
-Persistent activity in the lateral ventricles at 24 -48 hours
-Delay in the ascent of activity from the parasagittal region
-Possible delayed clearance of activity from the basal cisterns
-Remember the CSF is created in the ventricles
-CSF should flow out of the lateral ventricles but not back in
