VISTA opens new frontiers in
ultra high field MRI research
16 June 2006
The Virtual
Institute for Seven Tesla Applications (VISTA) is a Dutch initiative of
researchers from the University Medical Centers in Leiden (LUMC), Utrecht
(UUMC) and Nijmegen (St Radboud UMC) and from the FC Donders Center for
Cognitive Neuroimaging in Nijmegen. The aim of VISTA is to bundle the
expertise on ultra high field magnetic resonance imaging (MRI) in The
Netherlands into one powerful virtual institute and to give other MRI
researchers in the country access to ultra high field MRI expertise and
infrastructure.
The center of
gravity of VISTA comprises three MRI systems with a field strength of
7Tesla. In Leiden and Utrecht 7Tesla MRI systems manufactured by Philips
Medical Systems will be installed during the first quarter of 2007, whereas
the Nijmegen teams will have access to a recently installed Siemens 7Tesla
system at the University of Duisburg/Essen in Germany.
Over the years,
major breakthroughs in the field of MRI have been based on the availability
of systems operating at higher field strengths than before, and such
breakthroughs have given rise to the development of clinical MRI systems
with ever increasing field strengths.
Initially,
clinical MRI systems had field strengths of 0.5 Tesla or lower. Presently,
MRI systems with a field strength of 1.5 Tesla are the standard for clinical
settings in hospitals worldwide. Recently, systems operating at a field
strength of 3.0 Tesla started to be installed, mainly in university
hospitals and other research institutions. The availability of ultra high
field MRI systems with field strengths of 7 Tesla or higher has so far been
limited to some research sites where these systems were mostly built by
local teams of engineers and physicists.
Ultra high field MRI provides unique advantages that can be used not only to
obtain better results for many current diagnostic applications, but opens up
new fields of activity, by enabling previously unattainable applications.
Researchers are investigating and already showing promising results building
on the advantages of ultra high field strength MRI studies for:
-
Structural imaging, morphologic applications such as degenerative
neurological diseases like Alzheimer’s disease, Parkinson’s disease and
Multiple Sclerosis. New areas of MRI research include high-resolution
vascular imaging with opportunities for direct anatomic visualization of
angiogenesis of the microvasculature and monitoring the structural
effectiveness of anti-angiogenetic and genetic based drugs for the
treatment of cancer at an unprecedented level of detail.
-
Physiological and metabolic investigations can be
performed at an unmatched level of sensitivity. Activation studies in
the brain that utilise the BOLD (Blood Oxygen Level Dependent) contrast
mechanism benefit from increased sensitivity and spatial specificity.
ASL (Arterial Spin Labelling) techniques are more sensitive, as are
studies using exogenous paramagnetic contrast agents. In addition, ultra
high field strength substantially improves non invasive metabolic
analyses of tissues using MR spectroscopy (MRS).
-
Molecular applications such as quantitative imaging of
gene expression, marking stem cells and tracking their evolution or
targeting malignant cells with targeted contrast agents will be
facilitated due to the tremendous increase in signal-to-noise ratios as
well as the new possible contrast mechanisms.
MRI research in
The Netherlands has a long and successful tradition. So far an ultra high
field MRI system was lacking in the country, which hampered MRI research.
The costs of an
ultra high field MRI system are very high, not only because of the costs of
the scanner itself, but also because of the costs involved in the housing of
such a system (which requires all kinds of expensive adaptations). In
addition, at this point in time, 7Tesla research is not ready yet for all
kinds of applications. Rather, major work remains to be done, in terms of
developing techniques that exploit the theoretical advantages offered by
ultra high field, before these systems are ready for all kinds of
applications.
For such work,
teams of MRI experts with specific experience with ultra high field MRI are
needed. The height of the costs involving purchase and installment of a
7Tesla system, and the costs involved in hiring teams of experts prevent
most institutions from embarking on human ultra high field MRI research.
VISTA aimed at
overcoming such local budgetary limitations by creating a national platform
for 7Tesla research comprising human 7 Tesla MRI systems and teams of
experts and by seeking national funding. Funding was provided by the
national government recently, and VISTA will be a reality by mid 2007.
Mark A. van
Buchem, MD, PhD
Professor of Neuroradiology
Department of Radiology
Leiden University Medical Center,
Leiden, The Netherlands
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