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Real-time functional magnetic resonance imaging (rt-fMRI)
in patients with brain tumours: preliminary findings using motor and
language paradigms
Schwindack
C, Siminotto
E, Meyer
M, McNamara
A, Marshall
I, Wardlaw
JM, Whittle
IR
Division of Clinical Neurosciences, University of Edinburgh, Western General
Hospital, Edinburgh, UK.
Functional MRI (fMRI) shows areas of the brain that are active during a
task, but the standard approach (offline analysis after the imaging has
finished) precludes tailoring of the imaging to the individual patient, e.g.
for assessing normal function around an individual lesion.
The aims of the
study were to explore the technical feasibility of acquiring functional
images in real-time (rt-fMRI), develop the necessary software interfaces and
protocols for image acquisition, and to compare images of functional
activation acquired in real-time with the standard offline statistical
parametric method in patients with solitary brain tumours.
Patients with a
solitary supratentorial lesion were studied.
The rt-fMRI paradigms were
sequential finger opposition, ankle movement and language function (correct
recognition of grammatically violated sentences).
Datasets were analysed
using AFNI software (National Institute of Mental Health, Bethesda,
Maryland, USA) for the real-time analysis and SPM99 (Functional Imaging
Laboratory, University College, London, UK) for the offline analysis.
From
11 patients, useful data were obtained in nine.
The finger tapping task
produced most consistent activation between real-time and offline analysis
with good anatomic localization to the primary motor cortex contralateral to
the tapping finger.
Ankle movement produced weaker activation and
correlation with real-time analysis.
For the language task the offline
analysis provided reproducible activation patterns, but the real-time method
showed no activation at the chosen threshold of p = 0.001.
Tumourous areas
of brain did not show any activation with either method of analysis during
any task.
rt-fMRI is feasible and could be a valuable functional evaluation
tool in the planning of surgery for tumours in motor regions of the brain.
Further paradigm development is required for evaluation of language, and
possibly other more complex executive functions.
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