Ultrasound assessment Flashcards
What are some advantages of using ultrasound as an imaging modality?
Ultrasound is inexpensive, generally non-invasive, uses no ionizing radiation, and can rule out soft tissue abnormalities
What is the role of an ultrasound technologist (sonographer)?
Sonographers work in clinic or hospital settings, review requisitions and relevant patient medical history, conduct ultrasound examinations, and write technical impression reports for the radiologist
Explain the “piezoelectric effect” in the context of ultrasound
The piezoelectric effect involves the transformation of electrical energy into acoustic energy and vice versa. This is how ultrasound transducers both create and receive sound waves
How does an ultrasound machine determine the location of a pixel on an image?
the time it takes for the ultrasound signal to return is used to determine the location of a pixel on an acoustic line. Signal strength is used to determine the brightness of the pixel
What is acoustic impedance, and why is it important in ultrasound?
Acoustic impedance is a tissue’s resistance to the passage of ultrasound. It explains why we cannot see past bone and why a medium gel is required for imaging
Explain the Doppler effect in ultrasound imaging.
The Doppler effect is a change in frequency due to motion of a sound source, receiver, or reflector. In ultrasound, it is used to determine the speed of blood flow. The ultrasound transducer acts as a sound source, and red blood cells act as reflecting surfaces. Doppler shifts fall within the audible range, allowing users to hear the fetal heart rate
What is color Doppler imaging?
Color Doppler imaging superimposes a color-coded map of Doppler shifts onto a 2D image
What are the TRV and SAG planes in ultrasound imaging?
TRV refers to the transverse plane, and SAG refers to the sagittal plane. These are standard planes used for image orientation and anatomical reference.
How are structures described in an ultrasound image?
Ultrasound image descriptions are based on appearances: for example, anechoic (no echoes) for blood vessels, hypoechoic for neck muscles, and hyperechoic (echogenic) for muscle sheaths
What are some reasons a biophysical profile (BPP) appointment might be ordered?
A BPP may be ordered due to gestational diabetes, gestational hypertension, excessive or insufficient maternal weight gain, reduced fetal movements, complications in a prior pregnancy, advanced maternal age, and many other reasons
What are some features available on an ultrasound machine?
Ultrasound machines have features like 2D imaging (B-mode), freeze and still store, PW (pulsed wave) and CDI (color Doppler imaging), clip store (video), depth control, caliper, ABC labels, and calc function, as well as time gain compensations (TGCs)
How does the frequency of an ultrasound transducer affect its use?
- High-frequency transducers offer high resolution but poor penetration, making them suitable for superficial structures (thyroid, breast, scrotum, lumps).
- Low-frequency transducers have worse resolution but good penetration, used for the adult abdomen and pelvic exams.
- Medium frequency transducers are used for obstetrics or pediatric abdomen
When might a portable ultrasound machine be useful?
Portable ultrasound machines are less powerful but more convenient for use with ICU patients, in EMS FAST scans, and in research settings
What are some standard parasternal views in cardiac ultrasound?
Parasternal views include the parasternal long axis (PSLA) and parasternal short axis (PSSA). The PSSA is taken at the level of the aorta and at the level of the papillary muscles
What are some standard apical views in cardiac ultrasound?
Apical views include the apical 4-chamber, apical 5-chamber, apical 2-chamber, and apical 3-chamber
What are some visual assessments made during a cardiac ultrasound?
Visual assessments during cardiac ultrasounds include: wall motion, septal defects, valve regurgitation, valve anatomy, and pericardial effusions
What are some measurements taken during a cardiac ultrasound?
Measurements include: wall thickness, chamber size, aortic root diameter, tricuspid valve regurgitation, and pulmonary artery velocity. Also measured are atrium and ventricle sizes, ejection fraction, and velocity of blood through mitral and aortic valves, as well as tricuspid regurgitation and velocity of mitral annuli
Describe the progression of ischemic heart disease as it relates to structural changes in the heart.
Ischemic heart disease begins with CAD causing MI, leading to thickening of other sections of the myocardium. This can result in poor relaxation of the myocardium and dilation of the left ventricle, which then causes the left atrium to dilate due to increased filling resistance. Increased resistance in the LA causes remodeling of the right ventricle, and decreased filling in the RV causes right atrial dilation, ultimately resulting in congestive heart failure.
