SUTD Engineering Product Development (EPD) & SUTD-MIT International Design Center Distinguished Lecture (IEEE Singapore Section co-sponsored), New directions for brain MRI hardware and acquisition, by Professor Lawrence Wald (Harvard Medical School, MGH) | Peatixtag:peatix.com,2011:12019-10-30T22:19:34+08:00PeatixSUTDSUTD Engineering Product Development (EPD) & SUTD-MIT International Design Center Distinguished Lecture (IEEE Singapore Section co-sponsored), New directions for brain MRI hardware and acquisition, by Professor Lawrence Wald (Harvard Medical School, MGH)tag:peatix.com,2014:event-562822014-10-20T14:00:00SGT2014-10-20T14:00:00SGTSynopsis:
The possibility of studying the
living human body with resolution, sensitivity and speed considerably above
that provided by conventional MRI gradient encoding offers the potential to bring
new levels of biology under the lens of non-invasive imaging. Although most
academic MRI work focuses on acquisition and image reconstruction software, the
scanner hardware ultimately limits the capabilities of the technology, and
steady progress over the last 2 decades has shown that improvements are
possible. This talk will discuss our work and others toward improving the
detection and encoding technology of MRI.
Encoding, the ability to
spatially localize physical information into an image is traditionally done
with the Fourier encoding performed by application of switching, linear B0
field gradients. In the last 15 years, however,
more and more of the spatial encoding is derived from the detector array, who’s
spatial encoding ability is elegantly integrated with gradient encoding in parallel
imaging methodology. Our goal is to find the logical limits of this combination
and work to both increase the information content in the arrays (bigger
arrays), and introduce schemes which improve the time-efficiency of MR encoding
with little penalty in sensitivity. Recently, this has lead to a nearly 10 fold
speed up of the functional MRI acquisition.
Increasing the spatial resolution
of functional imaging to the columnar and laminar level has also started to be
routinely demonstrated, but remains fundamentally encoding limited. To address
this we have pushed highly parallel detection at high field and are currently
working to improve the B0 shim at 7T. Since poor B0 homogeneity at ultra high
field (7T) limits the time available for gradient encoding (to < T2*), we
develop a new, high-order matrix shimming approach at 3T and 7T. For MR
diffusion imaging, the applied diffusion gradients encode the diffusion of
water on a microscopic scale. For this application we introduce specialized/stronger
gradients designed to perform this more efficiently on a scanner designed
around diffusion imaging for the Human Connectome Project.
Finally, we note that the weight,
power and cooling requirements of gradient coils as well as the magnet
size/weight are barriers to using MRI in many locations such as an ambulance or
rural health clinics as well as point-of-care situations, such as surgical
recovery rooms. We have therefore developed a portable brain MRI system
(<100kg) which does not use traditional gradient coils at all, but encodes
brain images by rotating an inhomogeneous magnet around the patient’s head.
Bio-sketch of the lecturer:
Lawrence L. Wald, Ph.D., Received
a Ph.D. in Physics from the University of California at Berkeley in 1992 with a
thesis related to optical detection of NMR under the direction of Prof. Erwin
Hahn. He obtained further (postdoctoral) training in condensed matter physics
at
Berkeley and then in radiology/MRI
at the University of California at San Francisco where he worked on MR spectroscopic
imaging of brain tumors and the development of phased array coils for high
resolution imaging and spectroscopy with Profs. Vigneron and Nelson. He began
his academic career as an Instructor at the Harvard Medical School in the Brain
Imaging Center of McLean Hospital and since 1998 at the Massachusetts General
Hospital Dept. of Radiology in the NMR Center (now the A.A. Martinos Center for
Biomedical Imaging.) He is currently an Associate Professor of Radiology at the
Harvard Medical School and affiliated faculty in the Harvard MIT HST program
and a visiting Assoc. Prof. of EECS at MIT (2012, 2013). At the Martinos Center
he is Director of the MGH Imaging Core Facility.
He is a member of the College of
Fellows of the American Institute of Medical and Biological Engineers (AIMBE)
and a Fellow and former Board member of the International Society of Magnetic
Resonance in Medicine (ISMRM). He is an author on approximately 150
publications, 10 patents and enjoys an active role in educational programs at
MGH and MIT and through the ISMRM and Radiological Society of North America
(RSNA).
His group at MGH
works on hardware and software methods development for improved MRI of the
living human brain. Some of the current and recent projects include i) the
development of highly parallel receive array coils for high field imaging, ii) the
development of parallel imaging methods employing controlled aliasing for
improved Simultaneous MultiSlice (SMS) and 3D imaging, iii) Ultra-high field
(7T) methods for high resolution fMRI, parallel transmit pulse design and
hardware for reduced SAR imaging at 3T and 7T, iv) high gradient strength diffusion
imaging for the Human Connectome Project, v) the development of a portable low
field MRI systems using rotating B0 encoding. Updatestag:peatix.com,2014-10-17 15:57:022014-10-17 15:57:02Venue was changed to "Lecture Theater 4, Singapore University of Technology and Design, Singapore 138682". Orig#55986