Daniel Pflugfelder1, Kaveh Vahedipour1,
Kamil Uludag2, Nadim Jon Shah1,3, Tony Stcker1
1Institute of Neuroscience and Medicine
4, Medical Imaging Physics, Forschungszentrum Jlich GmbH, Jlich, Germany; 2Max-Planck
Institute for Biological Cybernetics, Tuebingen, Germany; 3Faculty
of Medicine, Department of Neurology, RWTH Aachen University, Aachen, Germany
To
increase the spatial specificity of the BOLD signal, a large ratio R of
microvascular to macrovascular BOLD signal is desirable. This can be be
achieved using spin echo sequences. To simplify the calculation the
extravascular BOLD signal (EV) is often approximated by a mono-exponential
decay (MEA). To investigate the effect of the MEA we calculated R for
multiple B0 and TE without using this approximation. The parameter range for
an optimal R was considerable different to the results obtained using the
MEA. This is mainly due to an vessel radius dependent delay of the EV which
is not reproduced by the MEA.
Keywords