Friday, 21 April 2017 Saturday, 22 April 2017 Physics for Physicists

738 Pages·2017·11.6 MB·English

Friday, 21 April Saturday, 22 Sunday, 23 Monday, 24 Tuesday, 25 Wednesday, Thursday, 27
2017 April 2017 April 2017 April 2017 April 2017 26 April 2017 April 2017
Friday, 21 April 2017
Go to top
Saturday, 22 April 2017
Go to top
Weekend Course
Physics for Physicists
Organizers:Herbert Köstler, Dipl.-Phys. & N. Jon Shah, Ph.D.
Moderators: Adrienne Campbell-Washburn &
Room 313BC Saturday 8:15 - 12:15
Armin Nagel
8:15 MRI: the Classical Description
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 T ,
1
T and T *relaxation. By additionally considering theeffects of magnetic field gradients, we
2 2
can determine the spatial location of the signal, producing images. All these effects can be
described by the Bloch equations, which give complete classical description of the
behaviour of magnetisation.
Gareth Barker
8:45 Signal & Noise in MRI
The signal-to-noise ratio (SNR) is a fundamental measure of quality and performance in
MRI, most frequently used as a metric for comparing and optimizing imaging sequences,
MR hardware (e.g., RF coils), or to assess and process new imaging and reconstruction
techniques. Clinically, signal and noise considerations are important for image assessment
such as in reliable lesion characterization, or in the context of accurate parameter fitting
(relaxometry). This presentation will review the basic principles relevant to SNR, sources
of noise, basic noise statistics, multi-channel noise, measurement of SNR and contrast-to-
noise ratio, and factors influencing SNR.
Claudia Hillenbrand
9:15 Spatial Encoding (k-Space, MRI as a Linear & Shift-Invariant System, PSF, MTF)
Michael Steckner
9:45 Break & Meet the Teachers
10:15 MRI: a Systems Overview
The “big three” sections of an MR scanner are well known; Magnet, Gradient system, and
RF system, and probably should have a fourth: Patient comfort and user experience
components. We start with a review of these components, current limitations, and
directions under investigation and continue to interaction between them needed to
harmonize operation.
Lawrence Wald
10:45 Bloch Equations & Typical MRI Contrast
This presentation will provide an overview of the typical forms of the Bloch Equations, the
physical mechanisms of relaxation phenomena as well as the basis of typical MRI
contrasts.
Tobias Wech
11:15 Pulse Sequence Check: Reality vs. Ideal
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 results of a given pulse sequence can be calculated and the
spatial encoding can be inverted to reconstruct an image. But what if these assumptions
are wrong?
Oliver Speck
11:45 Basic MR Safety (Magnetic Fields, Peripheral Nerve Stimulation, etc)
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 - interact with human tissue, but also with other materials exposed to
these fields. The physical interactions with human tissue do not cause irreversible
physiological effects, as long as certain limits are not exceeded. Concerning foreign
material (e.g. implants), the physical effects of the applied fields may cause severe
hazards for patients, staff, and material, if MR examinations are not performed properly.
Harald Kugel
12:15 Lunch & Meet the Teachers
Weekend Course
Introduction to fMRI: Task & Resting State fMRI
Methods/Analysis
Organizers:Jay J. Pillai, M.D. & Joshua S. Shimony, M.D., Ph.D.
Room 312 Saturday 8:15 - 12:15 Moderators: Jay Pillai & Benedikt Poser
8:15 BOLD Data Acquisition Considerations
Through a series of complex processes, under the umbrella term of neurovascular
coupling, neuronal activity ultimately manifests as a signal change in an MR image via the
blood-oxygenation level dependent (BOLD) contrast. Functional MRI (fMRI) capitalises on
this contrast mechanism to infer neuronal activity from BOLD contrast variation in a time
series, typically acquired while the participant engages in a task. This approach has
proved valuable in furthering our understanding of the working of the human brain. Here,
issues pertinent to acquiring data with sufficiently high sensitivity to detect such changes
are considered, e.g. susceptibility effects, physiological noise and approaches facilitating
high spatio-temporal resolution.
Martina Callaghan
8:45 BOLD Signal/Physiology
Functional MRI has become a standard technique for exploring brain function, however
this imaging modality is not a direct measure of neural activity. This course introduces the
source of Blood Oxygenation Level Dependent (BOLD) contrast and the physiological
mechanisms that drive the haemodynamic response to neural activity. The limitations and
challenges of using blood as a surrogate for brain function are discussed, particularly in
cohorts with differing cerebrovascular physiology. Potential solutions involving additional
imaging modalities and complementary MRI contrast mechanisms may enable accurate
understanding of the neuro-vascular processes underlying BOLD fMRI.
Molly Bright
9:15 General Linear Model Analysis of Task Based fMRI Data
The general linear model (GLM) is one of the most commonly utilized statistical platform
that is currently used in analyzing task-based fMRI data. In this talk we will introduce the
general over view and basic concepts of GLM and how it is used in this very specific
application of clinical neuroimaging. We will briefly review the history of introduction of
GLM into the fMRI community and later use some examples to demonstrate the utility in
analyzing fMRI data. In the end we will discuss some of its limitations.
Feroze Mohamed
9:45
Introduction to Resting State Functional Connectivity
Steven Stufflebeam
10:15 Break & Meet the Teachers
10:45 Data Driven & Exploratory Analyses
Independent component analysis (ICA) has grown to be a widely used and continually
developing staple for analyzing fMRI functional connectivity data. In this paper we discuss
some key observations and assumptions regarding ICA and also key new applications of
ICA to brain imaging data.
Vince Calhoun
11:15 Dynamic Functional Connectivity
Dynamic functional connectivity (DFC) is the study of time-varying changes in functional
interactions between brain regions. This talk will describe DFC methods along with the
challenges involved in such analyses. We will also highlight results demonstrating
associations between DFC and independently acquired measures of behavior, physiology,
and neural activity, and will discuss the potential for DFC features to serve as clinical
biomarkers.
Catie Chang
11:45 Network Analysis
This talk provides an introduction to network analysis of functional MRI, with an emphasis
on the use of graph theory for understanding distinct aspects of brain organisation and
dynamics.
Alex Fornito
12:15 Adjournment & Meet the Teachers
Weekend Course
Diffusion MRI: Principles & Applications
Organizers:Daniel C. Alexander, Ph.D. & Stephan E. Maier, M.D., Ph.D.
Room 311 Saturday 8:15 - 11:45 Moderators: Daniel Alexander & Stephan Maier
8:15 Introduction to Diffusion MRI
This lecture will cover the basics of diffusion MRI. We will explore how diffusion in
biological tissue serves as an in vivo microscope through its measurement with MRI by
varying both diffusion gradient and the diffusion time t, the time over which the molecules
diffuse. The concepts of q-space imaging, diffusion tensor imaging (DTI) and diffusion
kurtosis imaging (DKI) will be covered, as well as other higher order diffusion methods
(biophysical models versus representations). In addition, we will illustrate how varying the
diffusion time t provides complimentary information about microstructural length scales.
Els Fieremans
8:45 Diffusion Modeling and Microstructure Probing
This lecture presents the key concepts behind modelling diffusion MRI signal. Specifically,
it focuses on various techniques that go beyond the standard diffusion tensor model, and
aim to provide biomarkers which can be related to tissue microstructure.
Andrada Ianuș
9:15 Tracking Fiber Structures
Diffusion MRI tractography enables unprecedented visualization of the trajectory of white
matter pathways in vivo. This course will introduce the fundamental principles of tracking
fiber structures in diffusion MRI data, and will provide an overview of different tractography
methods. Participants will learn about the current capabilities and limitations of
tractography techniques for investigating white matter anatomy. Clinical applications of
tractography will be presented and challenges of using tractography findings for clinical
decision support will be discussed.
Sonia Pujol
9:45 Break & Meet the Teachers
10:15 Neuro Applications of Diffusion MRI
Michael Zeineh
10:45 Body Applications of Diffusion MRI
This presentation will review the added value of DWI in the body, particularly in the
oncology patients.
Bachir Taouli
11:15 Application of Diffusion MRI in Animal Models
This lecture will provide a brief overview of technical considerations involved in diffusion
MRI of small animals on preclinical scanners. Applications of diffusion MRI to examine
neuroanatomy and brain development in small animals will be covered. We will examine
the relations between metrics derived using different diffusion models and acquisition
schemes and white matter pathological changes in animal models of injury and disease. In
addition, emerging applications of diffusion MRI methods for characterization of brain
tissue microstructure in animal models will be explored.
Manisha Aggarwal
11:45 Adjournment & Meet the Teachers
Weekend Course
Introduction into Magnetic Resonance Spectroscopy
Organizers:Anke Henning, Ph.D. & Roland Kreis, Ph.D.
Room 314 Saturday 8:15 - 12:05 Moderators: Thomas Ernst & Harald Möller
8:15 Basic Principles of MRS (Chemical Shift, J-coupling, Spectral Resolution, Field Strength
Effects)
The basic principles of NMR are discussed based on classical concepts like compass
needles, bar magnets, precession and electromagnetic induction. More advanced topics
such as chemical shift, scalar coupling, T1 and T2 relaxation and basic MR sequences are
also covered.
Robin de Graaf
8:40 Localization (Sequences: semiLASER, PRESS, STEAM, Chemical Shift Displacement)
Accurate localization is key for MR spectra quality and metabolites quantification.
Metabolites low concentration and multiple frequencies pose more challenges in-vivo MRS
than MRI, due to B0 inhomogeneity, insufficient B1, chemical shift displacement, and
artifacts from lipids. Volume selection methods based on overlapping slices improves MRS
quality by limiting the region of interest to areas where B0 and B1 can be better controlled.
Spatial coverage can be improved by more modern approaches where arbitrary volumes
can be shaped with parallel transmit, multiple volumes disentangled by parallel imaged,
and different contributions to the MRS signal can be modeled in the reconstruction
Ovidiu Andronesi
9:05 Water & Lipid Suppression - VAPOR, WET, OVS, IR, Novel Approaches (MC, Crushers)
In this presentation, the need for water and lipid suppression, as well as the most widely
used approaches to achieve this are explained.
Vincent Boer
9:30 Pre-Scan Adjustments (B0 Shimming, F0, PO, Water Suppression)
The pre-scan adjustments, while nearly invisible to many practitioners, are very important
for the successful acquisition of many spectroscopic and imaging sequences. In this talk,
approaches and constructs specific to B0 and B1 optimization are discussed with
examples of methods and results.
Jullie Pan
9:55 Break & Meet the Teachers
10:25 MRSI (Basic Sequences & Acceleration)
Ulrike Dydak
10:50 Editing, 2D & UHF - Detection a Comprehensive Neurochemical Profile
While the vast majority of MRS applications focus on the strong resonances of NAA, Cr,
Cho and sometimes mIns and Glu+Gln, resonances from at least 15 neurochemicals, i.e.,
a comprehensive neurochemical profile are present in the spectrum. For detecting the
small, weakly represented neurochemical resonances that underlie the typically detected
large resonances such as NAA, Cr, Cho and mIns, options are: 1) to de-convolve all of the
signals that are present or 2) to edit, i.e., to set the signal of interest apart (at least
partially) from the others. Of course, there are advantages and disadvantages to each
approach.
Melissa Terpstra
11:15 Postprocessing & Quality Assurance
In-vivo MRS data is unavoidably degraded by experimental imperfections such as subject
motion, scanner drift, and eddy currents. Spectral preprocessing improves spectral quality
and quantification reliability, and is an indispensable part of any in-vivo MRS experiment.
MRS preprocessing is usually organized as a sequence, or ‘pipeline’ of individual
processing routines, each designed to address a specific issue with the data. This talk
covers some of the most common experimental issues affecting MRS data, and the
processing routines and pipelines that can address these issues.
Jamie Near
11:40 Spectral Fitting & Absolute Quantification
MRS quantification is complicated due to the metabolic resonance overlap and complex
line shapes. The modern methods for the spectral fitting increasingly relies on the linear
combination (LC) modeling algorithms. The absolute quantification can be carried out
using internal or external concentration references. The challenges remain in the following
areas: the generation of the accurate prior knowledge, creating proper model/constraints
for data fitting algorithms and choice of more robust concentration references.
Lana Kaiser
12:05 Adjournment & Meet the Teachers
Weekend Course
Cardiovascular MRI: Vascular
Organizers:James C. Carr, M.D. & Winfred A. Willinek, M.D.
Room 316A Saturday 8:15 - 11:45 Moderators: Darren Lum & Jeffrey Maki
8:15 Overview of CE & NCMRA Methods
Principles of Contrast enhanced and non contrast enhanced MRA will be reviewed, as well
as their clinical application.
Ruth Lim
8:35 Flow Imaging Techniques
Michael Hope
8:55 Contrast Agents
This lecture will deal with conventional Gd-based contrast agents. In particular the
molecular basis of the paramagnetic enhancement as well as Gd-complexes stability will
be addressed.
Daniela Delli Castelli
9:15 Break & Meet the Teachers
9:30 Imaging Techniques: Current & Future
Atherosclerosis, a systemic disease affecting large and medium sized arterial vessel walls
is a leading cause of mortality in the world. MRI is quickly becoming the imaging modality
of choice for visualizing atherosclerosis in the vessel wall. Atherosclerosis is evaluated in
vivo by multi-contrast dark blood turbo spin echo imaging to evaluate plaque burden and
composition. DCE- MRI can be used to evaluate plaque permeability. Recently,
quantitative MR imaging in the form of T1 and T2 mapping of the vessel wall and on
evaluating 4D flow, shear stress and circumferential strain in the arterial tree have become
popular.
Venkatesh Mani
9:50 Intracranial Atherosclerosis MR Imaging
· Intracranial artery atherosclerosis (ICAS) is one of the major causes of ischemic
stroke.
· MR vessel wall imaging techniques have been proposed and optimized dedicated
for characterizing ICAS.
· High risk ICAS features, such as T1-hyperintense, positive remodeling, and
contrast-enhancement, can be accurately identified by ICAS MR imaging.
Xihai Zhao
10:10 Coronary, Aorta & Peripheral Vessel Wall MR Imaging
Magnetic resonance (MR) has emerged as a leading noninvasive imaging modality for
assessing the wall disease beyond revealing luminal stenosis. Continued technical
innovations are being proposed for MR atherosclerosis imaging, particularly vessel wall
imaging, at coronary, aorta and peripheral vascular beds. Detailed knowledge about these
techniques would foster adoption of MR as an effective imaging tool in future research and
clinical practice. The present lecture will focus on technical developments in MR vessel
wall imaging of these arteries.
Zhaoyang Fan
10:30 Break & Meet the Teachers
10:45 Supra-Aortic & Intracranial Vascular Disease