Ultrasound Flashcards
What is an ultrasound?
Cyclic sound pressure above human hearing of 20kHz
Ultrasonography, what is it?
Medical imaging technique utilizing the interaction of these high frequency sound waves with tissue
Ultrasounds work by high frequency ___ waves produced by the ___. They are then bounced off the ___ and returned to the transducer. The ___ sound generates the image.
- Sound
- Transducer (probe)
- Object
- Reflected
Piezoelectric crystals purpose
They are inside the transducer and change shape when an electric current is applied to them. This change in shape generates the sound wave.
As sound travels through the body, some of the sound wave is ___. This limits how ___ the sound waves can penetrate. Different tissues have different ___ & ___ properties and generate different shades of gray & white.
- Absorbed
- Deep
- Absorption & reflection
Acoustic boundary is…
The reflection or “echo” generated when the wave travels from one tissue to the next
T/F: Ultrasound can image through bone and gas
False! It cannot image through either; it will appear white.
Ultrasound cannot image through… (4)
- Air filled lung
- Gas filled stomach or intestine
- Ribs
- Rocks, metal, or uroliths
Pulser purpose
Applies high amplitude voltage to energize the crystals
Transducer purpose
Converts electrical energy to mechanical (ultrasound) energy & vice versa
Receiver purpose
Detects and amplifies weak signals
Display purpose
Displays ultrasound signals in a variety of modes
Transducers
1. Linear array use
2. Circular array use
- Imaging uterus through rectum of large species
- Cardiac & transabdominal studies
General technique for ultrasounding (3)
- Furred areas are clipped.
- Animal is put in position appropriate for study.
- R lat or VD for SA abdomen
- L lat for cardiac
- Standing for large animal uterus or tendon - Coupling gel and/or dilute alcohol used for maximum skin/probe contact.
- Dark room (give best image for ultrasonographer).
- Quiet room (best pt cooperation)
- Calm demeanor (“)
- Comfortable body position (“)
- Foam cradles or tables
- Pillows
- Floor techniques
Equipment needed (4)
- Clippers
- Ultrasound machine
- Positioning cradles, pillows, & tables
- Ultrasound gel
B-mode on transducer, what is it?
- “Brightness” mode
- Used for “real time” images
M-mode on transducer, what is it?
- “Motion” mode
- Records changes in motion over time
- Used for measuring movement in the heart chambers
Ultrasound is superior to radiographs for visualizing… (5)
- Subtle tissue changes
- Motion diagnostics
- Collection techniques
- Safety
- Fluid filled abdomen or chest
Radiographs are superior to ultrasounds for visualizing… (6)
- Bone
- Lungs
- Size of very large organs
- Gas filled organs
- Counting late gestation fetuses
- Time of procedure
An image should be read in a specific ___. All organs should be imaged ___; once in ___ & ___. Sizes are ____ and recorded. Images, videos, and samples are ___.
- Pattern
- Longitudinal & transverse
- Measured
- Collected
Common sample collections utilized with an ultrasound (7)
- Cysto
1. Urine - Cytology
2. Tumors
3. Fluid
4. Organs (sleep, lymph nodes) - Biopsies
5. Liver
6. Kidneys
7. Tumors
The transducer reads in thin (1cm) “___ shaped” windows. To evaluate an entire organ the transducer is slowly “___” over the organ in ___ directions (perpendicular to each other).
- Fan
- Swept
- Both
Ultrasound guided biopsies require…
- Aseptic technique
- General anesthesia
- Clotting test
- Biopsy needle
- Formalin
