Physics & Knobology

Question 1

Which of the following statements regarding the use of M-mode imaging during lung sonography is correct?
A. M-mode imaging documents motion over time.
B. M-mode imaging is a useful adjunct to help identify and document pleural lung sliding.
C. The Seashore sign is the expected pattern in normal patients.
D. All of the above
E. A and C only

Answer 1

D. All of the above

Question 2

What is the speed of sound in soft tissue? 

Answer 2

1540 m/s

Question 3

Which of the following statements regarding transducer selection and machine settings for pulmonary imaging is correct?
A. Low- and high-frequency transducers both have roles in lung sonography.
B. A high-frequency linear transducer is ideally suited for imaging pleural sliding.
C. A low-frequency transducer can be used to visualize B-line artifacts.
D. All of the above
E. None of the above

Answer 3

D. All of the above

Question 4

What is Piezoelectric effect?

Answer 4

converts kinetic or mechanical energy, due to crystal deformation, into electrical energy

This is an electromechanical property of certain materials like quartz where an electrical current applied through the object generates vibrations resulting in pulsed sound waves. In turn, echos reflected back on the crystal generate changes in electrical resistance and current. In short, the conversion of electrical energy (a current applied over a voltage) to mechanical energy (sound waves) is the key!

Question 5

In general, lower frequency probes give you _______resolution, but have ______ tissue penetration. 

Answer 5

lower resolution, but have deeper tissue penetration

Question 6

In general, high frequency probes have _________resolution, but have _____ tissue penetration. 

Answer 6

Higher resolution, but have less tissue penetration