Other imaging modalities Flashcards
Name 5 advantages of CR/DR
- Greater tolerance
- See wider range of tissues
- Ability to computer-manipulate images
- Space saver
- Cannot lose radiographs
What is the other name for Computed radiography?
Digital radiography
Identify the 2 different types of DR
- Computed Radiography
- Digital Radiography
Is film required in DR + CR?
No
Is this DR or CR?
CR
Name the 4 pieces of equipment used in CR
- Imaging plate
- Cassette
- CR System
- Reader
True or False.
CR be used with + without a Grid
True
What are imaging plates made up of?
Photostimulable phosphor
(A luminescent material that stores X-ray energy and emits light when stimulated by visible light)
What replaced conventional film in CR?
An imaging plate
(IP)
What is an IP stored within?
A Cassette
Where can you place an IP?
Below or Above the table?
Both!
Depends on the practice’s set-up
Within what amount of time must you process an IP in CR?
Within an hour
(ASAP)
How long is the CR process?
1 - 2
minutes
What is an advantage of CR?
It can be viewed + analysed quickly
What should you do to IP daily?
Cleared, as they are very sensitive to scatter radiation!
What is an disadvantage of CR?
Expensive to set-up, intitally for VP
What should you use to clean an IP?
Imaging Plate Cleaner
Explain in 3 steps in basic terms, how CR works?
- During the expossure - the photostimulable phosphor within IP plate stores energy from x-ray photons in a semi-stable (electron trap) creating a latent image
- The cassette is labelled electrionically w/patient details before insserted into reader/digitizer
- IP is rremoved from the cassette automatically by the reader + passes through the rollers
Explain how a CR reader processes the latent x-ray image
- IP plate has photostimulable phosphor which is read by helium-neon laser within the digitizer
- This provides small amount of energy to the electrons in the electron trap
- This allows them to move back to their resting state + therefore release energy in the form of light
- The light produced is collected by a light guide + converted into an AES (Analogue Electrical Signal)
- The AES is amplified by a photomultiplier + digitized by an Analouge converter
- Once the image has recieved the bright light erases the IP + returned to the cassette for re-use
List as many different advantages of CR as possible!
- More sensitive to radiation
- CR plate lowers radiation dose
- Short exposure times
- Reduced saftey area
- Fewer repeat exposuures
- Objects with different thickness on 1 single image
- Faster processing times
- No chemicals are used
- Anaesthetic/sedation time is reduced
- Radiographic study is increased
- Dark rooms are surplus to requirement
- Image quality is greater as no overdevelopment issues
- Images can immediately be reviewed + sent to specialists
- Can be editied or manipulated
- Electronically stored
Give 3 advantages of CR images
- They can be emailed, burnt onto discs + USB sticks
- Can be viewed, edited + manipulated instantly
- Ease of retrieval + storage
Summarise how CR works in 4 basic steps
- Image is stored on radiation sensitive Phosphorous imaging plate
- This is converted into light, through a laser excitation in the CR reader
- This produceds a digital image on a Picture Archiving + Communication System (PACs)
- Can be reviewed + analysed immediately
Is DR expensive to set up?
Yes
Apart from an expensive DR x-ray machine, what else is required for the DR system to work?
An x-ray table
What type of radiography is this?
I am a piece of technology that produces an almost instantaneous image on the display screen without the use of a processing system..
Digital Radiography
I produce electrical signals via an intermediate light phase..
What am I?
In-direct Digital Radiography
I convert x-ray energy directly into a digitized electrical energy..
What am I?
Direct Digital Radiography
What type of radiography is this?
Digital Radiography
Explain the structure of the DR imaging plate
- Flat panel detectors
- Contain a thin film transistor array
- Made of Amorphous Selenium
- Arranged in a matrix
Can CR or DR be wired or wireless?
DR
What is the disadvantage of wired DR over wireless CR?
Wired DR is less flexiable than CR
What are the 2 advantages of wireless DR over CR?
Wireless is:
1. Very easy to use
1. More flexable than CR
List as many benefits of DR as you can
- Produces real-time image
- Highest quality of digital images
- Image is viewable in 1-2 seconds
- Zoom facility allows for magnification of areas
- Allows for maximum resolution - identify minuscule anomalies
- Benefical for othropaedics - can measure slopes of TPL view in theatre
- Changes in animal’s condition + healing process can be accurately viewed
- Immediate conversion of radiation intensity into a digital image
- Benefits similar to CR
- Moral of staff - less time spent on organising paperwork
Identify the 2 types of Direct radiography
- Flat panel system
- Charged Coupled Device system
How does a Flat Panel System work, in DR?
- Detector panel linked to x-ray equipment
- Converts to x-ray energy to lighy
- Then to a digital signal
How does a Charged Coupled Device System work, in DR?
- Fluorescent screen under a x-ray table
- The computer screen is linked to this
What type of plate costs at least double the cost of the CR system?
DR Plates
What are DR plates coated in?
Amorphous Selenium
What are DR plates comparable to?
Large, single, Computer chip
What are DR plates?
Specialised plates that convert light to digital signals - directly - without the use of a reader
What type of plates are these?
DR Plates
What is the cause of Poor Image Contrast in DR?
+
How can you rectify it?
- Uncorrect table algorithim
- Rectified by selecting anatomical area before prrocessing
What is the cause of Alternating bands of dark + Light across the image, which can change in direction or when zoomed in in DR?
+
How can you rectify it?
- Moire
(A wavelike, cloudy or frosted appearance of textile fabrics or metallic surfaces) - Rectified by not using a grid
What is the cause of Lucent halo around orthopaedic device in DR?
+
How can you rectify it?
- Uberschwinger
(An artifact of digital processing that may be mistaken for bone lysi) - Rectified by checking correct algorithm
What is the cause of Linear white line across entire CR image in DR?
+
How can you rectify it?
- Dirt on light guide or CR digitizer
- Rectified by cleaning the light guide following manafacturers guidelines
What is the cause of Grainy appearence, inclusive of areas out with the animal, within the Primary beam in DR?
+
How can you rectify it?
- Underexposure (too light)
- Rectified by increasing the kV +/or mAs
What is the cause of Thinner areas black with no visiable detail in DR?
+
How can you rectify it?
- Overexposure (too dark)
- Reduce exposure factors, different algorithms
What is the cause of White specks on lines/image in DR?
+
How can you rectify it?
- Dirt or hair (artifiact) in or on cassette
- Rectified by cleaning the cassettes regularly, according to manafacturer guidelines
How are DR images viewed?
On a Monitor
What 8 ways can DR images be manipulated?
- Rotation
- Flipping
- Magnification
- Adjustment of density/contrast
- Inversion (black/white)
- Annotation (if forgotten L/R markers)
- Measurements
- Comparison of different images
What format must you send DR images to the BVA?
Digitally, in DICOM format
How should DR images be stored as?
DICOM
(Digital Imaging + Communications in Medicine)
What does DICOM stand for in DR?
Digital Imaging + Communications in Medicine
What does DICOM allow for when viewing images?
Viewed across all modes of imaging, including MRI + CT
How does DICOM allow you to edit/add to DR images?
You can imbedd it with:
* Px details
* Owner details
* Species
* Breed
Name a few ways in which X-ray images can be stored in DR
- CDs
- DVDs
- USB
- Cloud systems/online storage
- Back-ups
Why is additional storage usually required with DR?
Because computers usually have minimal storage
How are DR images stored as?
- DICOM
- Jpegs
What is the online Central Archive used in DR?
Picture Archiving + Communications Systems (PACS)
True or False.
PACS doesn’t save DR images automatically in a secure location, which is only off site
False.
They are automatically saved to a secure location, which can be either on or off site
What can a PAC System allow + store in DR?
- Automically store images to secure location
- Store px ID, VS + VP details
- Store up to 250,000 images
- Allows for images to be viewed in multiple areas of VP + anywhere in the world
Multple areas = Consult rooms, theatres etc
Name 2 benefits of PACs System in DR
- Recent radiographs can be stored w/previous images + stored together
- Enables continuity of patient care + assessment/developments
What is Teleradiography>
The ability to transfer digital files from 1 location to another
What does Teleradiology allow for?
- Quicker + more efficient storage than to CDs + DVDs
- Reports can be returned to the practice
What is Teleradiology commonly used for?
To send to refferals or to send to specialists for interpretation
What fault has occured during this exposure?
The tube head or patient moved during exposure
What is contrast media also known as?
Contrast Radiography
What is Contrast Media Radiography?
Method of using a special dye to study organs
What is the liquid called that is used in Contrast Media studies?
A Contrast Media or Medium
How does Contrast Media Radiography help VS’s?
Helps visualise internal structures that may not be visable on standard x-rays
What method or type of radiology has been used here?
+
What has it shown in this patient?
- Contrast Radiography
- Shown what looks like large uroliths!
Give another name given to a Contrast Medium
Contrast Agent
What do Radiocontrast agents provide when using Contrast Radiography?
They are substances that can be fed into the px to enhance the visibility of the internal structures
Identify 4 types of radiography can Contrast Radiography aid in?
- Computed Tomography (CT)
- MRI
- Protectional radiography
- Fluoroscopy
Name 2 types of Contrast media
- Water-soluble Iodine
- Barium Sulfate
Why is Contrast Media used?
To address the lack of contrast by selectively absorbing more x-ray photons than the soft-tissues
Soft tissues that appear white on the image
What 4 structures can a Contrast Media be introduced into?
- Blood vessels
- Viscera
- Cavities
- Joints
Identify the 3 things in which Contrast Media can be gained from this study?
- Anatomy
- Integrity
- Function
Name the 3 types of Contrast Agents
- Negative
- Postitive
- Double contrast
What 3 things must Contrast Mediums be in order to be safe to use within the patient?
They must be:
1. Non-irritant
2. Non-toxic
3. Be able to be excreted from the body
What does a contrast medium do when an x-ray is taken?
It attenuates the x-ray beams differently to the soft tissues
Why is time an important factor when it comes to Contrast Media?
Because Contrast Medium’s require to be in the body for a certain time, that is long enough, in order for it to be observed on an x-ray
Identify 2 Negative Contrast Medium
- Gas or CO2
- Air
Identify 2 Positive Contrast Medium
- Water-soluble Iodine
- Barium Sulphate
What is Double Contrast?
The use of a positive + negative contrast agents in combination
Name 3 pairs of Double contrast agents
- Iodine + Air
- Barium Sulphate + Air
- H20/Water + Air
Name 2 indications for Barium Sulphate
- GI Tract
- Crystals
Name 2 indications for Water-Soluble Iodine
- GI Tract
- Urinary Tract
What contrast medium can be used in contrast studies, to study the spine + muscoskeletal structures?
Water-Soluble Iodine
Name 4 indications for using the postitive contrast medium, Barium Sulphate
- Non-invasive
- Good for constipated animals, as it is a laxative
- As it is water-soluble, it won’t cause any damage internally
- Little to no chance of anaphylaxis
Name a contraindication of using the postitive contrast medium, Barium Sulphate
If there are tears within the surrounding structures or cavities, it will leak into other body cavities
Name an indication for using the postitive contrast medium, Water-Soluble Iodine
Can be excreted by the kidneys
Name 6 contraindications for using the postitive contrast medium, Barium Sulphate
- If the powder isn’t mixed right it can cause issues
- Can cause anaphylaxis
- Difficult to administer
- More expensive than Barium Sulphate
- Can cause a fall in BP
- Cannot be used in conscious px
What type of contrast medium would you use if you were to perform a Double Contrast Cystogram?
Water-soluble Iodine + Air
or
Water-soluble Iodine + Co2
What precautions should be taken when using a Double Contrast Cystogram?
- Not to rupture the bladder
- Monitor for anaphylaxis
A dog is presented with the symptoms associated with an Intestinal perforation.
The VS has decided to perform a series of Gastro-Intestinal radiographs to confirm the dx.
You have been asked to prepare for the following study.
A) Explain how you would prepare the patient
B) Whatequipment required?
C) what contrast agent should be chosen?
D) What is the rationale for this?
A) Preparing the px:
* Fast for 12 hrs
* Check when last eaten
* Gain O consent
* Check vitals
* Perform enema
* Provide pain relief
* Sedation
B) Equipment required:
* Needle
* Syringe
* Feeding tube
* Postioning aids
* Contrast agent
* Funnel
* Dosing syringe or beaker
* X-ray machine
* PPE
C) Contrast agent to be used:
* Water-soluble Iodine
D) Contrast agent chosen:
* As Barium Sulphate can cause issues if possible peritionitis (fluid in abdo - fatal) or abdominal perforation
A puppy has been brought into the VP for investigation.
The main CSign is Anuria.
The VS admits the puppy for further investigation w/a view to performing a Double Contrast Cystogram.
A) What equipment is required?
B) What Contrast Medium should be chosen?
The VS asks you to assist with the taking of a urine sample.
C) At what stage should this be performed?
A) Necessary equipment:
* Sedation
* Needle
* Syringe
* Long needle for Cystogram
* Contrast medium
B) Water-Soluble Iodine
C) Take prior to contrast medium induction, as it creates a high USG + false positive contrast medium!
Which type of Contrast Media has a very low physical density + appears radiolucent?
Negative
When is a negative Contrast medium used?
To define the location of a viscus, organ or vacates
When is a positive Contrast medium used?
To define the location of anatomical detail
GIve 4 Negative Contrast medium examples
- Room air
- Co2
- Nitrous Oxide
- O2
What type of contrast media is this?
I have a high atomic number + can attenuate the x-ray beam more within visucs, organs or vacates
Positive
What type of contrast medium appears radiopaque on x-ray?
Positive
In basic terms, what occurs using a double contrast in a Gastrogram?
Barium Sulphate is used to line the organ
+
Distended with air
In basic terms, what occurs using a double contrast in a Cystogram?
Water-soluble Iodine is used to line the bladder
+
Distended with air
What is this?
Barium Sulphate contrast medium
What contrast medium is commonly used for GI studies?
Barium Sulphate
List 3 advantages of using Barium Sulphate
- Inert
- Soluble
- Theapeutic effects - if animal has diarrhoea
List 3 disadvantages of using Barium Sulphate
- Can cause a foregin body reaction if it leaks
- Constipation
- Risk of aspiration (if secondary condition)
Name the 4 preparations of Barium Sulphate
- Suspension
- Paste
- Powder
- BIPS (Barium Impregnated Spheres)
What 3 areas of the body can Barium Sulphate suspension used for?
- Swallowing
- Oesophageal studies
- GI Tract
What area of the body can Barium Sulphate paste used for?
Pharyngeal + Oesophageal ulcerations
Why is Barium Sulphate powder not commonly used?
Because it can clump readily, reducing the quality of the study
What can Barium Impregnated Spheres (BIPS) be used to evaluate?
To evaluate:
1. Obstructions
2. GI mobility
3. Intestinal transient time
What contrast medium could be used for this?
Barium Sulphate!
(if no perforations)
What is this?
Water-Soluble Iodine
(Contrast medium)
Identify 4 Water-soluble Iodine examples
- Conray
- Gastrografin
- Hypaque
- Urografin
Name 4 reasons to when Water-soluble Iodine is contraindicated
- Difficult to administer for GI studies
- Poor contrast for bowels (Contrast diluted in transition through the bowel)
- IV may cause fall in BP
- Cause anaphylaxis
- Can’t be used in conscious animals
Why is Water-soluble Iodine be difficult to administer in GI studies?
Because it is:
* Unpalatable
* An irritant
Why should you not administer Water-soluble Iodine be given to conscious patients?
Can cause whining + retching
Identify 8 uses for the use of Water-soluble Iodine contrast medium
- Intravascular studies
- Lower Urinary Tract (Bladder most commonly)
- Joints
- Salivary glands
- Lacrimal sac + ducts
- Peripheral sinuses + Fistulae
- Myelography
- Lymphangiography
What are the 2 types of Water-soluble Iodine?
- Ionic
- Non-ionic
What contrast medium would be used for this?
+
What type of radiography may this be?
- Contrast medium = Water-soluble Iodine
- Myelography
What should you do to Ionic Water-soluble Iodine before adminstering to a paitent?
It’s viscous, so should be warm to body temperture before use
What are the 3 contraindications for using Ionic Water-soluble Iodine?
- Hypotension
- Dehydration
- Severe Renal Failure
What are the 2 common uses for Ionic Water-soluble Iodine?
- Cardiovascular studies
- Urinary Tract studies
True or False.
Non-Ionic solutions of Water-soluble Iodine causes less allregic reactions in comparions to Ionic solutions
True!
True or False.
Ionic Water-soluble Iodine is more expensive than Non-Ionic
False, Non-Ionic is more expensive!
What type of Water-soluble Iodine preparation provides a sharper contrast border for an increased time
Ionic or Non-Ionic?
Non-Ionic water-soluble Iodine
Is Ionic or Non-Ionic water-soluble Iodine used more commonly for Myelography + Arthrography?
Non-Ionic
What type of water-soluble Iodine can be used when Cardiovascular + Urinary Tract is contraindicated?
Non-Ionic
What is this?
Lower Osmolar Ionic Media
Give an example of a Lower Osmolar Ionic Media
Hexabrix
Is Lower Osmolar Ionic Media radiopaque or omnipaque?
Omnipaque
Give 2 advantages of Lower Osmolar Ionic Media in comparison to Water-soluble Iodine
- Fewer side effects than Water-soluble Iodine
- Better contrast in GI Tract than Water soluble Iodine
Why is Lower Osmolar Ionic Media safer for Myelography than Non-Ionic Water-soluble Iodine?
Because it is non-ionic
Name 3 types of Iodine preparations for contrast studies
- Cholecystopaques
- Viscous Iodine
- Oily Iodine
How is Cholecystopaques iodine preparation administered to patients?
IV
How is Cholecystopaques iodine preparation excreted in the body?
Excreted by the Liver
What is Viscous Iodine commonly used for?
Bronchoscopy
What is Oily Iodine commonly used for?
Lymphangiography
List 5 methods used for Contrast Radiography
- Myelography
- Gastrogram
- Retrograde urethrography
- IV Urography
- Cystogram
Why is Myelography used?
To indicate lesions that are not detectable on ordinary x-rays
Name 3 reasons to when Myelography could be indicated
- Spinal pain
- Neurological signs
- Prolapsed intervertebral discs
Should a px be sedated or anaesthetised for Myelography?
Anaesthetised
8 ..
What equipment should be used to perpare a patient for Myelography?
- Anaesthetic
- Clippeers
- Spinal needles (20 + 22 gauge - depending on px size)
- Warmed contrast media
- Syringe
- Sample bottle for CSF
- Surgical scrub
- Sterile gloves
What 3 things should be performed when performing a Myelogram?
- Patient is clipped caudal to skull or lumbar spine
- Contrast agent is warmed
- Head is elevated
Identify 3 contrast mediums that can be warmed for use in a Myelogram
- Iopamidol
- Omnipaque
- Iohexol
What method of restraint should be used for Myelography?
GA
What is method being performed here?
Cisterna Magna puncture
What 2 ways is a Myelogram is introduced into a px?
- Cisterna Magna puncture
- Lumbar puncture