Topic 4 : Ultrasounds and Endoscopes Flashcards
What is an ultrasound and how does it work?
An ultrasound is a computer - an ultrasound probe is connected, which transmits and receives ultrasounds waves using a row of vibrating crystals, which are sequences by the computer so that when the prove receives these ultrasound waves following transmission into the tissue, a lice image is formed.
Are A-mode ultrasounds used in veterinary medicine?
N, is is not practical for diagnostic veterinary medicine as it does not give a picture of the tissue
What is the most common mode of ultrasounds in veterinary practices?
B- Mode ultrasounds
What does B-mode stand for
Brightness mode in which every echo received is transformed into a dot.
In the case of a strong echo (ie bouncing off bone) in ultrasounds will the dot be bright or dark?
The dot will be bright
In the case of a weak echo (ie continuing on through fluid) in ultrasounds will the dot be bright or dark?
The dot will be dark
What is an M-mode ultrasound
M-mode stands for motion, and it allows us to compare movement in tissue over time
What is M-mode used for
It is commonly used to examine the heart and foetal heart, and to provide heart rate
In an M-mode ultrasound what measurement do the vertical dots and horizontal dots represent?
Vertical dots represent 1cm
Horizontal dots represent 0.5 seconds
What is a doppler ultrasound
Doppler ultrasound is a technique used to measure the flow of blood through your arteries and blood vessels—usually those in your extremities. Vascular flow studies, also known as blood flow studies, can detect abnormal flow within a blood vessel.
Define hypoechoeic and what dot it will produce on an ultrasound
‘low echo’ producing tissue - the echo is weak, therefore the dot is dark (fluid)
Define hyperchoeic and what dot it will produce on an ultrasound
‘high echo’ producing tissue - the echo is strong, therefore the dot is bright (bone)
Define echogenic
tissue that generates an echo
What is the basic range of ultrasound probes
3MHz
5MHz
7.5MHz
10MHz
What are 3MHz probes used for?
examining deep objects such as hearts and abdominal tissue
What are 5MHz probes used for?
Commonly used in equine work and general reproductive work along with general diagnostic scanning for colic, lung pathology ect.
Too large to provide fine detail for tendons, joints and liagments
What are 7MHz probes used for?
Provide fine detail for tendons and con pick up minute pathology close to the surface area
What do linear probes emit?
Ultrasound wave in a line
What do Curvilinear probes emit?
Ultrasound waves in a curved line
What do sector emit probes emit?
Waves through a narrow window..
What does the gain part of an ultrasound machine do?
– gain increases the power to the probe. This increase in power results in an increase in brightness of the returning echoes. Gain should be set at the lowest power possible, to obtain adequate detail of near and far tissue. If it is set too high, adequate detail is lost.
How does fluid appear in an ultrasound?
Fluid is hypocechoeic and appears black
How does air appear in an ultrasound?
Air is hyperechoeic and produces reverberation artefact, so air show is horizontal lines echoing continually backwards and forwards
How does tissue appear in an ultrasound?
Tissue is moderately hypoechoeic, is echogenic and produces shades of grey
How does fat appear in an ultrasound?
Fat is hypoechoeic and appears black
What position do you put the patient in for an ultrasound of the heart?
Left lateral recumbency (heart vied from underneath through a ‘window’ cut in the table )
What position do you put the patient in for an ultrasound of the Kidney (right)?
Left lateral recumbency
What position do you put the patient in for an ultrasound of the heart?
Right lateral recumbency
What position do you put the patient in for an ultrasound of the liver?
Dorsal Recumbancy
What position do you put the patient in for an ultrasound of the spleen?
Right lateral recumbancy
What position do you put the patient in for an ultrasound of the bladder?
Standing, dorsal or lateral recumbency
What position do you put the patient in for an ultrasound of the prostate?
Dorsal or lateral recumbancy
Where would you clip when taking an ultrasound of the heart?
Usually 3-6 intercostal spaces between sternum and costochondral junction. Best site at apex beat.
Where would you clip when taking an ultrasound of the kidney (right)?
Below sub-lumbar muscles over the last two intercostal spaces
Where would you clip when taking an ultrasound of the kidney (left)?
Below sub-lumbar muscles caudal to the last rib
Where would you clip when taking an ultrasound of the liver?
Mid-ling, from costal arch to umbilicus extending several centimeters from mid-line
Where would you clip when taking an ultrasound of the spleen?
Wide area from twelfth intercostal space to umbilicus usually from left flank to mid-line region or along left flank
Where would you clip when taking an ultrasound of the bladder?
Medline between public brim and umbilicus
Where would you clip when taking an ultrasound of the prostate?
Immediately cranial to pubic brim and to one side of prepuce
How would you view the heart with an ultrasound?
The heart i surrounded by air-filled lungs (preventing visualisation) so imaging of the heart is restricted to three windows between the lung lobes
What are the three windows used to view the heart in an ultrasound?
- Right 4th to 5th intercostals space, between the sternum and costochondral junction.
- Left 5th to 7th intercostals space, close to the sternum
- Left 3rd to 4th intercostals space between the sternum and costochondral junction.
Why would you use the doppler ultrasound on the heart?
To measure the flow of blood through the chambers of the heart to determine if the heart is functioning normally
What organs are commonly inspected with an ultrasound?
- liver
- spleen
- kidneys
- bladder
- prostate
Can focal lesions be seen through ultrasounds?
Focal lesion may be seen if they are large enough. Approximately 5-10mm in diameter or larger will be seen.
What is indirect ultrasounds guided biopsy?
Where the ultrasound is used to identify the lesion and assess the depth and angle of needle insertion required to sample the lesion.
Once this is achieved the ultrasound probe is removed and the needle is inserted freehand.
What does freehand puncture involve?
It involved holding the transducer in one hand and biopsy instrument in the other. Used ultrasonic visulisation, the needle is positioned at the desired site.
It is difficult to keep the needle under constant visulisation and this technique may require considerable practice.
How do you use needle guidance systems?
- easiest technique
- probe fitted with a needle guide that directs the biopsy needle down a specific track within view of the ultrasound scan
- some machines will even display the proposed needle pathway superimposed on the image on the screen
Can a uterus on a non-pregnant bitch be seen through ultrasonography?
No
What changes in the testes can ultrasonography detect?
Neoplasia, torsion or infection
Define neoplasia
the presence or formation of new, abnormal growth of tissue
Other than pregnancy what can ultrasonography detect on females reproductive systems?
Detection of cysts and tumors of the ovaries
Uterine neoplasia
What are endoscopes?
Endoscopes are expensive and delicate pieces of equipment used to visually examine the internal structure of an animal via an orifice.
Define orifice
an opening, particularly one in the body such as a nostril or the anus
What is a felxible endoscope used for?
Used for gastrointestinal endoscopy, colonoscopy and bronchoscopy
What is a rigid endoscope used for?
Rhinoscopy, cystoscopy, laparoscopy, orthoscopy, vaginoscopy and thoracoscopy
Define Rhinoscopy
examination of the nasal passages.
Define cystoscopy
is a procedure used to see inside your urinary bladder and urethra
Define laparoscopy
a surgical procedure in which a fibre-optic instrument is inserted through the abdominal wall to view the organs in the abdomen or permit small-scale surgery.
Define orthoscopy
surgical procedure on a joint in which an examination and sometimes treatment of damage is performed using an arthroscope, an endoscope that is inserted into the joint through a small incision
define thoracoscopy
procedure involving internal examination, biopsy, and/or resection of disease or masses within the pleural cavity and thoracic cavity
What are the three parts of a flexible endoscope?
- Glass fibre bundles contained within a protective tubing
- A light source
- A water source
How does an endoscope work?
Light passes from the light source down the glass fibres to illuminate the tissue under observation. The water is used to keep the lens clean.
What are the endoscope sizes for dogs?
Dogs: 1 metre long, 9.2mm diameter, 2.8mm biopsy channel (GIF XQ200)
What are the endoscope sizes for cats?
Cats: 1 metre long, 7.9mm diameter, 2mm biopsy channel (GIF XP20)
What are the endoscope sizes for horses?
Horses: custom made (3 metres long)
What three things should you never do with an endoscope when cleaning it?
- Immerse it completely in water
- Place is hot air oven
- Drop, kink or knock the glass tubing
Should an endoscope be kept in a carry case?
No, this can damage the optical fibres.
It should be hung in a dry well ventillated and secure place
What is a laparoscope?
A form of a rigid endoscope - allows the surgeon to view the contents of the abdominal cavity
What is a laparoscope used for?
To perform key-hole surgical procedures
Name the 3 key-hole incisions used for a laparotomy surgical site:
- To insert the laparoscopic viewer
- To insert the insufflators
- To insert the laparoscopic surgical instruments – eg scalpel, cautery, clamps/haemostats, scissors, etc
What is an arthroscope?
a rigid endoscope used for examining and performing surgical procedures within joints
What are the functions of an arthroscope?
confirmed diagnosis of articular cartilage damage and osteoarthritis, confirmed diagnosis of cruciate ligament rupture, and repair or removal of meniscle tears
Other uses for rigid endoscopes include vaginoscopy, thoracoscopy and rhinoscopy
