ISMRM 24th Annual Meeting & Exhibition • 07-13 May 2016 • Singapore |
Weekend
Educational Course: Physics for Physicists
Skill Level: Intermediate
to Advanced
Organizers: Thomas Foo,
Ph.D. & N. Jon Shah, Ph.D.
Saturday 07 May 2016 |
Overview
This course will describe commonly used imaging pulse sequences and
their building blocks, data acquisition and artifact suppression
strategies and basic and advanced image reconstruction techniques.
Target Audience
MR physicists and engineers, pulse sequence developers and clinicians
who want to deepen their understanding of MRI acquisition and
reconstruction methods. Individuals who will likely benefit most from
the course are those who have recently completed or will complete a
graduate educational program in MR physics, chemistry, applied
mathematics or engineering and those practitioners of MR with extensive
practical experience but seek to obtain a more systematic physics
foundation.
Educational Objectives
Upon completion of this course, participants should be able to:
- Develop a systematic
understanding of pulse sequence building blocks and components;
- Gain an in-depth
understanding of advanced data acquisition strategies, and their
potential and limitations;
- Describe common approaches to
address motion;
- Understand the
state-of-the-art fast imaging techniques;
- Grasp advanced image
reconstruction algorithms; and
- Identify common artifacts and
understand how to reduce them.
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PROGRAM |
Moderator: Seung-Kyun Lee, Ed Wu |
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An Introduction to the Basics of MRI |
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08:30
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MRI: The Classical Description ![](play.gif)
Gareth Barker
The NMR (Nuclear Magnetic Resonance) signal can be
described classically by considering the motion of the
net magnetisation (the vector sum of magnetic moments of
individual nuclei). By considering individual
isochromats – i.e. subsets of the spins that are
behaving identically– we can visualise how the received
signal will decay away due to T1, T2 and
T2* relaxation. By additionally considering
the effects of magnetic field gradients, we can
spatially localise the signal, extending NMR to MRI
(Magnetic Resonance Imaging). All these effects can be
described by the Bloch equations, which give complete
classical description of the behaviour of magnetisation.
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09:00
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MRI: A Systems Overview ![](play.gif)
Mark E. Ladd1
1Medical Physics in Radiology, German Cancer
Research Center, Heidelberg, Germany
· Basic
understanding of how an MRI works can be achieved by
comprehending its major functional subsystems.
· The
subsystem currently experiencing the greatest innovation
is RF transmission.
· Software
defines the look and feel of the system and is the most
important differentiator between systems.
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09:30
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Basic MR Safety (Magnetic Fields, Peripheral Nerve
Stimulation, etc.) ![](play.gif)
Harald Kugel1
1Department of Clinical Radiology, University
of Muenster, Muenster, Germany
Magnetic resonance techniques are considered to be not
harmful. The three electromagnetic fields used for MR -
static magnetic field, switched gradient fields, and
radio frequency field - do not result in irreversible
changes of human tissue, as long as certain limits are
not exceeded. However, the applied fields show effects,
which may cause severe hazards for patients, staff, and
material, if MR examinations are not performed properly.
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10:00
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Break & Meet the Teachers |
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Contrast Manipulation |
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10:30
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Bloch Equations & Typical MRI Contrast ![](play.gif)
Nikolaus Weiskopf1,2
1Department of Neurophysics, Max Planck
Institute for Human Cognitive and Brain Sciences,
Leipzig, Germany, 2Wellcome
Trust Centre for Neuroimaging, University College
London, London, United Kingdom
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11:00
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Sequences and Simulations ![](play.gif)
Martin John Graves1
1Radiology, Cambridge University Hospitals,
Cambridge, United Kingdom
This presentation will provide an overview of the main
gradient echo based (gradient spoiled, RF spoiled and
balanced steady state free precession) and
conventional/fast spin echo based pulse sequences and
will illustrate some methods by which their behaviour
can be simulated
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11:30
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Pulse Sequence Check: Reality vs. Ideal ![](play.gif)
Oliver Speck1
1Biomedical Magnetic Resonance, Otto von
Guericke University, Magdeburg, Germany
The effect of any pulse sequence on the magnetization in
an object can be predicted very accurately using the
Bloch equation. A general algebraic inversion of the
Bloch equation is not possible and thus, the full set of
object and system properties and parameters cannot be
derived from measurement data directly. Using a few
assumptions and neglecting possible deviations, the
contrast of a given pulse sequence can be calculated and
the spatial encoding can be inverted to reconstruct an
image.
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12:00
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Lunch & Meet the Teachers |
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Echo Planar Imaging |
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13:30
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Basics of an EPI Acquisition ![](play.gif)
Eric C. Wong1
1UC San Diego
Echo Planar Imaging (1), or EPI, is a prototype for
pulse sequences that sample two dimensions of K-space
after a single excitation. 2D scanning after a single
excitation means that signal modulations unrelated to
applied gradient fields, such as transverse relaxation
and resonance offsets, distribute across two dimensions
in k-space and image space. EPI is highly demanding of
gradient performance and fidelity. Gradient hardware
advances have enabled the implementation of EPI, and
continue to improve the utility and robustness of EPI.
There are complex tradeoffs involved in the design of
EPI pulse sequences and selection of EPI parameters with
regard to gradient performance, SNR, image artifacts,
ramp sampling, and other pulse sequence features.
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14:00
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EPI Applications: What we Can See Using EPI as an Engine ![](play.gif)
Peter Jezzard1
1University of Oxford
Introduction to the uses of EPI as an acquisition
‘engine’ in advanced structural and functional pulse
sequences · Overview of the principles of functional
MRI, arterial spin labelling, diffusion imaging and
chemical exchange saturation transfer imaging. ·
Description of the pulse sequence modules required to
achieve these image contrasts. · Summary of the
different flavours of each method, and the tricks
required to minimize confounding artifacts.
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14:30
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EPI Artifacts and Correections ![](play.gif)
Maxim Zaitsev1
1Dept. of Radiology - Medical Physics,
University Medical Centre Freiburg, Freiburg, Germany
Since its conception in 1977 echo planar imaging (EPI)
remains famous for being a host of a variety of
artefacts. Recent improvements in the gradient
technology and the availability of receiver arrays
offset some of the problems, which however was quickly
counterbalanced by a general trend of increasing the
main magnetic field strength and a common demand of
increasing spatial resolution. Therefore understanding
the physics behind the EPI artefacts continues to be
important, as it allows one both to compose optimal
protocols minimizing the possible damage at source and
devise suitable post-acquisition strategies for
correcting remaining imperfections.
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15:00
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Break & Meet the Teachers |
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Diffusion Imaging for Physicists |
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15:30
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Diffusion Weighted Imaging & Applications ![](play.gif)
Rita Gouveia Nunes1
1Universidade de Lisboa, Lisboa, Portugal
Diffusion-weighted imaging (DWI) makes use of molecular
water motion to probe tissue microstructure. This
lecture will focus on the basic principles of DWI
acquisition. After introducing the most commonly used
diffusion modules, the main acquisition challenges will
be discussed. Typical acquisition approaches will be
presented, including single-shot and multi-shot
sequences. Examples of frequent DWI image artefacts will
be shown, and some of the approaches available for
minimizing or correcting for their effect will be
presented. The main applications of DWI to brain and
body imaging will also be presented, focusing on stroke
and lesion characterization.
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16:00
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Diffusion Tensor Imaging & Applications ![](play.gif)
Ana-Maria Oros-Peusquens1
1Forschungszentrum Juelich, Germany
The presentation will discuss, among others, the
diffusion tensor model and diffusion indices,
acquisition and data sampling strategies, validation of
DTI and applications: tractography in neurosurgery,
brain connectivity in vivo, gray matter structure and
connectivity in fixed tissue.
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16:30
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Beyond the Tensor Model ![](play.gif)
Evren Ozarslan1
1Bogazici University
Diffusion tensor imaging (DTI) is widely employed to
characterize diffusion anisotropy in multi-directional
diffusion MR acquisitions. However, the DTI model has
well-known limitations primarily because it assumes
diffusion to be Gaussian. In this talk, DTI’s
limitations will be discussed for three cases: (i) the
presence of orientational complexity, (ii) nonlinearity
of the signal decay curves, and (iii) dependence on the
timing parameters of the sequence. Several alternative
approaches will be outlined and it will be argued that a
cost-benefit analysis has to be performed before
abandoning the diffusion tensor model.
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17:00
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q-Space: What is it? ![](play.gif)
Flavio Dell'Acqua1
1Neuroimaging, King's College London, London,
United Kingdom
In this lecture the concepts behind q-space and q-space
imaging will be reviewed. Starting from an historical
overview on the major advances, the development of the
q-space formalism and the concept of the diffusion
propagator will be described and used to explain the
origin of diffraction peaks and their possible
application to infer pore sizes and other
microstructural features. Q-space and Propagator based
imaging techniques will then be introduced highlighting
advantages and limitations of these techniques. Finally,
the use of diffusion time as an new contrast to probe
microstructure at different length scales will be
discussed.
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17:30
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Adjournment & Meet the
Teachers |
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The International
Society for Magnetic Resonance in Medicine is accredited by the
Accreditation Council for
Continuing Medical Education to provide continuing medical education
for physicians. |