Principles of Biomedical Imaging

Module aims

The course aims to analyse and explain how the non-ionising imaging modalities ultrasound, MRI and light-based imaging can provide information on the anatomy, composition and physiology of the human body.

Learning outcomes

Learning Outcomes - Knowledge and Understanding

  • To explain how each non-ionising imaging modality (including ultrasound, MRI and optical imaging), is designed and operated to display tissue properties;
  • To describe examples of clinical and research applications for each imaging modality;
  • To be able to compare and contrast which tissue properties each non-ionising imaging modality can display;
  • To analyse the accuracy with which each non-ionising imaging modality can measure the relevant tissue properties;
  • To describe the properties of the contrast agents, and how the image may be manipulated using contrast enhancement techniques and how that relates to tissue function and morphology;
  • To assess how flow, diffusion and molecular targets may be displayed and measured by the imaging technique.

Learning Outcomes - Intellectual Skills

  • To be able to calculate the contrast and resolution of an imaging method

Learning Outcomes - Practical Skills

  • To be able to calculate the contrast and resolution of an imaging method from data previously captured using imaging processing algorithms

Module syllabus

Ultrasonic Imaging:

  • Transducer arrays: Linear, linear phased, annular. lateral and axial resolution, beam steering, focussing and apodization.QA protocols, acoustic output measurements, preventative maintenance protocols, first line maintenance
  • High Frame Rate Ultrasound: Principles, beamforming algorithms, coherent compounding, motion artefacts, advanced beamforming/signal processing
  • Elastography: Tissue elasticity properties, strain based elastography, shear wave based elastography, elastography image formation
  • 3D Ultrasound: Position sensing, image data acquisition, interpolation techniques, display modes
  • Ultrasound TomographyContrast Agents and Harmonic Imaging: Composition and acoustic properties of contrast agents, modelling, areas of clinical application, fundamental and harmonic imaging, molecular imaging
  • Dosimetry and Safety: Thermal, non-linear and cavitation effects. cellular effects. cooling mechanisms in vivo. ultrasound field measurements, thermal and mechanical indices, operating parameters, international safety regulations.
  • Therapeutic Techniques

Magnetic Resonance Imaging:

  • NMR phenomenon. Reference frames, resonance and Bloch equations
  • MR Hardware: Magnet design and constraints, superconductivity, gradient coil design, gradient performance, eddy currents and shielding. Components of Receiver chain: coil design, coil loading, quadrature and array coils, SNR vs field strength
  • Advanced Pulse Sequences: CPMG, stimulated echoes. fast imaging sequences: k-space, segmented sequences, FLASH, turbo-FLASH, Fast spin-echo, Echo-planar, sequential scanning, parallel imaging, compressed sensing
  • Clinical Scanning Techniques: Contrast agents, paramagnetic ions, positive and negative contrast agents, fat suppression, chemical shift, chemical and motion artefacts, gating, in and out-phase techniques, chemical selection, spatial saturation
  • MR Angiography: Physics of flow effects, in-flow, phase effects, gradient moment rephasing, time-of-flight MRA, phase-contrast MRA, 2D and 3D techniques, TONE, MIP, quantitative velocity measurement, Fourier encoding.
  • Advanced Contrast Mechanisms: BOLD effect, diffusion, perfusion, magnetisation transfer
  • MR Spectroscopy: Chemical shift, common nuclei for investigation, spectral features, line widths, technical requirements, localisation methods, CSI.
  • MR Image Quality: SNR and resolution, assessing image quality, test objects, parameters, test materials.
  • MR Safety II: Bioeffects & safety, biological effects of static, time-varying fields, magneto-hydrodynamic effect, neuro-muscular stimulation, heating, SAR, exposure limits and units. Pacemakers, implants, standards, guidance and organisational issues, siting and environmental issues.

Biomedical Optics:

  • Optical Coherence Tomography, micro-confocal endoscopy, opto-acoustic imaging

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Pre-requisites

 Students must be able to perform basic algebra. Students must be familiar with Fourier Transforms.

Teaching methods

Lectures: 20 hours

Study groups: 8 hours

Assessments

Examinations:

‚óŹ  Written exam: ; 100% weighting

    Rubrics: 3 compulsory questions (1 ultrasound, 1 MRI, 1 optical imaging)