Functional MRI
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How it works: Functional MRI is based on changes in blood flow to regions of the brain associated with a particular activity. When you move your fingers, the cells in your brain that tell your finger to move need more oxygenated blood. The MRI scanner can measure these very small changes in blood flow and display them on an image.
Equipment: Our functional MRI suite uses the latest Phillips 3.0 tesla magnet coupled with a state of the art Invivo (http://www.invivocorp.com/fmri/esys.php) paradigm delivery system. Our system uses a 30 inch LCD monitor viewable through a system of mirrors to show patients a customizable visual based FMRI examination. We have technologists who are trained on Functional MRI techniques and all of our exams are personally tailored and monitored by a CAQ board certified neuroradiologist.
Benefits: FMRI is used for presurgical planning for an intracranial operation that could potentially involved eloquent cerebral cortex. The FMRI exam is tailored to the location of the brain lesion, regions of clinical concern, and the normal brain adjacent to it. The goal is to allow the neurosurgeon or clinician to plan the optimal, least invasive approach to a mass, and to allow the surgeon to more completely excise a mass while preserving as much normal function as possible. FMRI allows a patient to better understand the potential risks of having surgery. Many studies have shown improved morbidity and increased survival rates in patients who have had preoperative FMRI (http://thejns.org/doi/abs/10.3171/jns.1998.89.3.0412).
Exam Preparation: The FMRI is slightly different from other MRI exams:
- You cannot be sedated during the exam. You must be fully alert and responsive. Many patients who are claustrophobic find the LCD monitor a welcome distraction and can still tolerate the examination.
- If you wear corrective lenses for reading, please know your prescription at the time of scheduling. We have MRI compatible glasses and lenses. If you wear contacts, please wear them to the exam.
- Avoid caffeine 1 hour prior to the exam.
- If English is not your primary language please let us know. We currently offer the full FMRI exam in English and Spanish. Other languages may be possible with advanced notice.
- The language tests require the ability to quickly read brief words and sentences of text.
What to expect: FMRI can be done with or without intravenous contrast. If the brain lesion is known to enhance, we prefer to do the study with intravenous contrast to better delineate the lesion. When you arrive the FMRI technologist will review the FMRI paradigms outside of the scanner. Once in the scanner routine high resolution anatomic images will be obtained first followed by the FMRI. The FMRI exam takes longer than a typical MRI (Usually 1.5 hours total). During this time we obtain anatomical images, diffusion tensor imaging, perform tractography, and the Functional MRI. The functional component of the exam is tailored to the individual patient and may test both language and motor functions. The combination of anatomic imaging, DTI based Tractography, and FMRI gives the clinician the greatest possible amount of information about the functional status of the brain.
Please see the attached powerpoint show
References:
http://thejns.org/doi/full/10.3171/jns.2003.98.4.0764?select23=Go+to+section
http://thejns.org/doi/abs/10.3171/jns.1998.89.3.0412
http://www.nejm.org/doi/full/10.1056/NEJMoa067819
http://journals.lww.com/neurosurgery/Abstract/2004/10000/Functional_Magnetic_Resonance_Imaging_integrated.24.aspx
