Lesson 06: Pulse-echo Imaging and Display Modes. This lesson contains 22 slides plus 15 multiple-choice questions.

Transcription

1 Lesson 06: Pulse-echo Imaging and Display Modes This lesson contains 22 slides plus 15 multiple-choice questions. Accompanying text for the slides in this lesson can be found on pages 26 through 32 in the textbook:

2 ULTRASOUND IMAGING AND INSTRUMENTATION

3 Pulse-echo Imaging Voltage Sound Rectification Amplification Compensation Demodulation Compression Rejection Scan conversion Preprocessing Postprocessing Magnification

4 TRANSDUCER EXCITATION AND OUTPUT POWER TRANSMITTER TRANSMIT POWER OUTPUT ACOUSTIC POWER ENERGY OUTPUT

5 TIMING PRF >1000 Hz

6 RECEIVER TGC GAIN MASTER GAIN OVERALL GAIN

7 TIME GAIN COMPENSATION

8 TIME GAIN COMPENSATION

9 GAIN vs. OUTPUT

10 TGC INCORRECT SETTINGS

11 DYNAMIC RANGE DYNAMIC RANGE COMPRESSION LOG COMPRESSION COMPRESS

12 DYNAMIC RANGE 50 db 30 db

13 NOISE REDUCTION REJECT low-level echoes (noise) anechoic BEFORE REJECT AFTER REJECT

14 NOISE REDUCTION Frame averaging (persistence) Frequency compounding Spatial compounding

15 HARMONICS A wave whose frequency is a whole-number multiple of that of another

16 DISPLAY MODES

17 2D & M-mode B-SCAN (2-D) M-MODE

18 B-scan

19 B-scan

20 PATIENT-ORIENTED B-SCAN PLANES

21 ORGAN-ORIENTED B-SCAN PLANES

22 B-SCAN WITH A-SCAN OPHTHALMIC IMAGE

23 OBSTETRICAL IMAGES 2D 3D

24 Answers to the following FIFTEEN practice questions were derived from material in the textbook:

25 Question 1 Which of the following controls is part of the receiver in a pulse-echo ultrasound system? BRIGHTNESS XMTR PWR RES TGC POST PROCESSING Page 28

26 Question 1 Which of the following controls is part of the receiver in a pulse-echo ultrasound system? BRIGHTNESS XMTR PWR RES TGC POST PROCESSING Page 28

27 Question 2 The sensitivity of an ultrasound system may be determined by measuring the duty factor strongest echoes that are received bandwidth amplitude range of the received echoes weakest echoes that are received Page 27

28 Question 2 The sensitivity of an ultrasound system may be determined by measuring the duty factor strongest echoes that are received bandwidth amplitude range of the received echoes weakest echoes that are received Page 27

29 Question 3 If the OVERALL GAIN is decreased, only the brightness of the near echoes will decrease the energy to the patient is decreased the brightness of all echoes will decrease equally the frequency will decrease only the brightness of the far echoes will decrease Page 28

30 Question 3 If the OVERALL GAIN is decreased, only the brightness of the near echoes will decrease the energy to the patient is decreased the brightness of all echoes will decrease equally the frequency will decrease only the brightness of the far echoes will decrease Page 28

31 Question 4 If the ultrasound system displays only the echoes from strong reflectors and nothing else, the sonographer should increase the lateral resolution decrease the output power increase the overall gain decrease the slope of the TGC adjust the far gain Page 28

32 Question 4 If the ultrasound system displays only the echoes from strong reflectors and nothing else, the sonographer should increase the lateral resolution decrease the output power increase the overall gain decrease the slope of the TGC adjust the far gain Page 28

33 Question 5 The control that is used to suppress unwanted, low level echoes or background information is TGC POST PROCESSING DYNAMIC RANGE REJECT WRITE MAGNIFICATION Page 29

34 Question 5 The control that is used to suppress unwanted, low level echoes or background information is TGC POST PROCESSING DYNAMIC RANGE REJECT WRITE MAGNIFICATION Page 29

35 Question 6 Electrical interference could appear in an image as shadowing behind a poorly attenuating structure a decrease in far field penetration enhancement behind a highly reflective structure low-level echoes within a cyst a loss of axial resolution Page 29

36 Question 6 Electrical interference could appear in an image as shadowing behind a poorly attenuating structure a decrease in far field penetration enhancement behind a highly reflective structure low-level echoes within a cyst a loss of axial resolution Page 29

37 Question 7 The receiver dynamic range that provides the best opportunity for the display of a wide range of gray shades is 3 db 6 db 9 db 60 db 0 db Page 29

38 Question 7 The receiver dynamic range that provides the best opportunity for the display of a wide range of gray shades is 3 db 6 db 9 db 60 db 0 db Page 29

39 Question 8 Compression is used in the receiver of an ultrasound system to reduce the duty factor increase the difference between small and large amplitude signals reduce the range of signal amplitudes provide post processing reduce the sound energy entering the patient Page 29

40 Question 8 Compression is used in the receiver of an ultrasound system to reduce the duty factor increase the difference between small and large amplitude signals reduce the range of signal amplitudes provide post processing reduce the sound energy entering the patient Page 29

41 Question 9 The OUTPUT control on a pulse-echo ultrasound system controls the amount of amplification in the receiver varies the dynamic range in the receiver is used to equalize differences in received echo amplitudes due to differences in the depths of the reflectors varies the voltage that the beamformer supplies to the transducer does not have any affect on the amount of sound energy that enters a patient Page 26

42 Question 9 The OUTPUT control on a pulse-echo ultrasound system controls the amount of amplification in the receiver varies the dynamic range in the receiver is used to equalize differences in received echo amplitudes due to differences in the depths of the reflectors varies the voltage that the beamformer supplies to the transducer does not have any affect on the amount of sound energy that enters a patient Page 26

43 Question 10 The OUTPUT control in a pulse-echo system does NOT affect the excitation voltage that is applied to the transducer frequency of the sound that leaves the transducer energy that enters the patient amount of energy leaving a transducer overall gain that may be required Page 26

44 Question 10 The OUTPUT control in a pulse-echo system does NOT affect the excitation voltage that is applied to the transducer frequency of the sound that leaves the transducer energy that enters the patient amount of energy leaving a transducer overall gain that may be required Page 26

45 Question 11 From a safety standpoint, which one of the following methods is BEST? Low transmitter output and high receiver gain High near gain and low far gain High reject and high transmitter output High transmitter output and low receiver gain Low near gain and high far gain Page 28

46 Question 11 From a safety standpoint, which one of the following methods is BEST? Low transmitter output and high receiver gain High near gain and low far gain High reject and high transmitter output High transmitter output and low receiver gain Low near gain and high far gain Page 28

47 Question 12 The dynamic range of the receiver of an ultrasound system refers to the ability of the receiver to track a rapidly moving structure range of echo signal frequencies that can be processed without distortion speed with which the receiver recovers following the excitation pulse to the transducer depth range in tissue over which moving echoes can be received range of echo signal amplitudes that can be processed without distortion Page 29

48 Question 12 The dynamic range of the receiver of an ultrasound system refers to the ability of the receiver to track a rapidly moving structure range of echo signal frequencies that can be processed without distortion speed with which the receiver recovers following the excitation pulse to the transducer depth range in tissue over which moving echoes can be received range of echo signal amplitudes that can be processed without distortion Page 29

49 Question 13 Which of the following results in an increased acoustic exposure to the patient? application of reject increase in the swept gain slope rate increase in the television monitor brightness increase in the beamformer voltage to the transducer increase in the overall gain Page 26

50 Question 13 Which of the following results in an increased acoustic exposure to the patient? application of reject increase in the swept gain slope rate increase in the television monitor brightness increase in the beamformer voltage to the transducer increase in the overall gain Page 26

51 Question 14 Which of the following is NOT a brightness-modulated display, based on the amplitude of received echoes? B mode B scan A mode Real time gray scale M mode Page 31

52 Question 14 Which of the following is NOT a brightness-modulated display, based on the amplitude of received echoes? B mode B scan A mode Real time gray scale M mode Page 31

53 Question 15 Increasing the gain of a pulse-echo system results in higher A-mode echoes. This is due to increased amount of sound emitted by the transducer increased amount of sound reflected increased efficiency of transducer conversion of sound into electricity increased amplification in the receiver decreased amplification in the receiver Pages 28 and 31

54 Question 15 Increasing the gain of a pulse-echo system results in higher A-mode echoes. This is due to increased amount of sound emitted by the transducer increased amount of sound reflected increased efficiency of transducer conversion of sound into electricity increased amplification in the receiver decreased amplification in the receiver Pages 28 and 31

55 END OF LESSON 06 For information on the accompanying textbook, visit the Website: