MRS426 Diagnostic Ultrasound (8)

This subject examines the basic physics, instrumentation and some clinical aspects of medical diagnostic ultrasound. The propagation of ultrasound in attenuative media, the instrumentation associated with different ultrasound modalities, common imaging artifacts, potential bioeffects, and recommendations for the safe use of ultrasound are all considered. In addition, aspects of 2D real-time greyscale imaging as applied to selected clinical areas, including abdominal, obstetric and gynaecological ultrasound, are covered. The interpretation of diagnostic information gained from the various ultrasound modalities is also given attention.


Session 2 (60)
Wagga Wagga Campus

Continuing students should consult the SAL for current offering details: MRS426. Where differences exist between the Handbook and the SAL, the SAL should be taken as containing the correct subject offering details.

Subject Information

Grading System



One session


School of Dentistry and Health Sciences

Enrolment Restrictions

Available to students in BMedRadSc(with specialisations) and BAppSc(MedImaging) Conversion

Learning Outcomes

Upon successful completion of this subject, students should:
  • be able to explain, with the use of calculations, the physics of the nature, production, propagation and attenuation of ultrasound in medical diagnosis.
  • be able to explain, using relevant calculations, the technology of the various imaging modes used in ultrasonography.
  • be able to explain, with the use of relevant calculations, the basic principles of Doppler ultrasound, and the technologies and purpose of diagnostic CW-, PW- and Colour Doppler.
  • be able to explain the cause and appearance of the many grey-scale artifacts that occur in diagnostic ultrasound images, and how they may be eradicated or minimised when required.
  • be able to justify the importance of diagnostic ultrasound safety, explain the necessity for the use of safety indices and safety statements, and describe the potential damage mechanisms.
  • be able to describe normal sonographic appearances, common anomalies, and protocols used in upper abdomen, female pelvis and obstetric examinations.


This subject will cover the following topics:

Basic ultrasound physics
Longitudinal waves, sound wave velocity, displacement- and pressure- expressions for ultrasound waves, specific acoustic impedance, wave intensity and amplitude, decibel notation, reflection and refraction of ultrasound, Snell's law, reflection and transmission coefficients, absorption, wave intensity and attenuation, the ultrasound transducer, resonance frequencies, design for pulse-echo applications, acoustic (quarter-wave) and electric matching, Q-factor, bandwidth, frequency spectrum of pulses, near- and far- fields and beam-shape dependence on frequency and crystal diameter, beam inhomogeneities, mechanical and electronic focussing of ultrasound beams.

A- and M-mode scanning
Pulse-echo ranging, average ultrasound propagation speed, basic principles of A-mode instrumentation, instrumentation controls, time-gain-compensation (TGC), axial resolution, artifacts, clinical applications, pulsed-mode, duty factor, power in ultrasound beams, ultrasound intensity descriptors (SATA, SPTA, etc.), M-mode instrumentation and applications.

B-mode scanning
Static B-mode (very briefly) and comparison to A-mode; linear-, sector-, and compound-scanning, digital scan converters, TV monitor, digital grey-scale displays, pre-processing and post-processing options, axial and lateral resolution, 2D real-time B-mode (grey-scale) scanning, frame-rates and temporal (motion) resolution, contact scanning and water-path delay scanning, grey-scale imaging artifacts, rapid mechanical probe scanning, linear and phased array electronic probe scanning, electronic focussing and steering, endosonography, instrument quality control.

Doppler instrumentation
Basic physics of the Doppler effect and frequency shift due to moving structures, continuous wave (CW) Doppler instrumentation, directional Doppler, clinical use of CW Doppler, range-gated pulsed Doppler instrument, spectral analysis, aliasing, Nyquist criterion, Duplex Doppler, Colour Doppler (briefly).

Bioeffects and safety of diagnostic ultrasound
Thermal effects, radiation force, stable and transient cavitation, intensity thresholds for bioeffects, diagnostic ultrasound dosimetry, safety margins, protection against ill-effects, AIUM safety recommendations.

Abdominal ultrasound - 2D real-time applications
Brief overview of sonographic terminology, sonography examinations (2D real-time) of the upper abdomen, including liver, gall bladder and bile duct, pancreas, spleen, renal, adrenal and blood vessels. Also consideration of patient appointments and patient preparation, indications and typical findings.

Obstetric ultrasound - 2D real-time applications
18 week scan, gestational analysis including foetal biometric quantities in determining gestational age ranges, symmetrical and asymmetrical intra-uterine growth retardation, typical foetal abnormalities, principle and methodology of the Biophysical Profile Scoring (BPS) technique.

Gynaecologic ultrasound - 2D real-time applications
Aspects of female pelvis scanning, uterus in cyclic changes, pathology of uterus and ovaries, key aspects of ultrasonic diagnosis of ectopic pregnancies.

Practical work
The practical work will relate to a number of topics studied in lectures. Practical details will be presented in a practical manual and other handouts presented in the lab.

Indicative Assessment

The following table summarises the assessment tasks for the online offering of MRS426 in Session 2 2020. Please note this is a guide only. Assessment tasks are regularly updated and can also differ to suit the mode of study (online or on campus).

Item Number
Value %
Online test 1
Written report
Online test 2
Final exam

The information contained in the CSU Handbook was accurate at the date of publication: May 2021. The University reserves the right to vary the information at any time without notice.