Lesson 1B (Part 2)

Question 1

What is the frequency range for a transabdominal probe?

Answer 1

3-5MHz

Question 2

What is the frequency range for a transvaginal probe?

Answer 2

5-10MHz

Question 3

What happens with a higher resolution probe?

Answer 3

Less penetration

Question 4

When is a transvaginal probes used in pregnancies? (2)

Answer 4

1. During the early stages

2. Later pregnancies to asses the cervix

Question 5

Transperineal US

Answer 5

Correctly evaluates sphincters in patients with fecal incontinence, postpartum and also following surgical repair of obstetric tears
- 3-5MHz probe

Question 6

Translabial US

Answer 6

Is the most commonly used imaging method in the investigation of women with lower urinary tract symptoms and female pelvic organ prolapse
- 3-5MHz probe

Question 7

What can transperineal and translabial US do? (2)

Answer 7

1. Less intrusive

2. Can provide useful information in later pregnancies

Question 8

What kind of information does transperineal and translabial US provide? (2)

Answer 8

1. Cervix length

2. Fetal head positioning

Question 9

What must be done to sonogrpahic equipment?

Answer 9

Calibrated and/or serviced routinely

- cleaned appropriately on a per use basis

Question 10

Who is able to request for an obstetrical US? (3)

Answer 10

1. Physicians
2. Obstetricians
3. Midwives

Question 11

What is important to do for continual quality patient care?

Answer 11

Provide appropriate documentation

• images of all normal/abnormal areas are documented
• gestational age and measurements

Question 12

What do all images require in an OB exam? (3)

Answer 12

1. Date of the exam
2. Appropriate patient identification
3. Right and left side of the anatomy

Question 13

What does most US software contain?

Answer 13

An Obstetrical calculation package

- summarizes important measurements

Question 14

What AIUM statements does Sonography Canada endorse? (2)

Answer 14

1. No independently confirmed adverse effects caused by exposure from present diagnostic ultrasound instruments
2. Fetal ultrasound should be performed only when there is a valid medical reason, and the lowest possible ultrasonic exposure settings and should be used to gain the necessary diagnostic information under the ALARA Principle

Question 15

ALARA

Answer 15

As low as reasonably achievable

- this is the main principle behind all ultrasound examinations and patient safety

Question 16

What 2 things contribute to patients exposure and need to be minimized?

Answer 16

1. Output intensity

2. Exposure time

Question 17

Minimizing output intensity

Answer 17

Appropriate quality control to maintain appropriate output settings on ultrasound equipment

Question 18

How do you minimize the output intensity? (4)

Answer 18

1. Reducing power settings on the machine
2. Using Doppler (higher intensity) only when necessary
3. Only when medically necessary
4. Perform examinations as efficiently as possible
   - minimize repeat examinations

Question 19

Thermal bioeffects

Answer 19

Some of ultrasound energy is absorbed by the tissue it travels through

Question 20

What does thermal bioeffetcs cause?

Answer 20

Increase in temperature of the tissues

Question 21

What can heat affect? (2)

Answer 21

1. Chemical reactions
2. Molecular bonds
   - potential teratogen

Question 22

Teratogen

Answer 22

Agent causing malformation of embryo

Question 23

Thermal index

Answer 23

Is a measurement of ultrasound conditions that can change the temperature of a tissue

Question 24

What does thermal index 1 indicate?

Answer 24

That the tissues may increase in temperature 1°C

Question 25

What is the thermal index threshold for potentially hazardous conditions?

Answer 25

1.5-2 deg C

Question 26

What is TI for soft tissue?

Answer 26

< 8 weeks

Question 27

What is TI for bone?

Answer 27

> 8 weeks

Question 28

Why does bone have a lower output for a thermal index?

Answer 28

Has a higher attenuation

Question 29

What should the mechanical index be less than?

Answer 29

1.9

Question 30

What does mechanical bioeffects have a potential for?

Answer 30

Cavitation

Question 31

Cavitation

Answer 31

Is a phenomenon in which rapid changes of pressure in a liquid lead to the formation of small vapor-filled cavities, in places where the pressure is relatively low - when subjected to higher pressure, these cavities, called "bubbles" or "voids", collapse and can generate an intense shock wave

Question 32

TI

Answer 32

Thermal index