Added value of MRI-guided neuronavigation
Transcranial Magnetic Stimulation (TMS) requires accurate placement of the TMS coil over the targeted brain area. Conventional placement methods in TMS are based merely on external landmarks of the head (5 cm rule, 10-20 EEG). This leads to inaccuracies in targeting of this brain area and herewith to suboptimal results in TMS research and therapies, and high variability of treatment outcome for different patients.
To overcome this problem, MRI-guided neuronavigation is developed which is providing added value to TMS stimulation for more precise, real-time neuronavigation of TMS pulses. Neuronavigation aligns the MRI scan aquired at an earlier point in time with the head of the patient, by measuring several fiducial points on the head with a tracker. Also the TMS coil and the head of the patient is tracked. This allows Neuronavigation software to accurately guide a TMS pulse to the intended neuroanatomical structure with millimeter precision. Several groups have now demonstrated clearly increased efficiency of rTMS in treatment of e.g depression (Fitzgerald, 2009). By using an individualized MRI scan of the subject, the TMS coil can accurately be guided to the specific brain target and by doing so correct for differences in the shape and the size of that specific brain (Ruohonen, 2010) and the outter shape of the head.
Please note: some manufacturers offer navigation equipment for TMS that only follows a coil in relation to a model head, so without individual MRI scans. This is not neuronavigation; and the added value of such navigation systems has not been empirically demonstrated, and only offers a method for reproducible TMS coil placement. For true neuronavigation with a benefit for treatment, an individual MRI scan is required. Such a required T1 weighted MRI scan takes a maximum of 10 minutes on an MRI scanner today.
We offer a CE certified and FDA cleared neuronavigation device that meets all your requirements.
Neggers, S.F. Langerak T.R., Schutter D.J.L.G., MAndl, R.C.W., Ramsey, N.F., Lemmens P.J.J. , Postma A., Ramsey, N.F. A stereotactic method for image guided transcranial magnetic stimulation validated with fMRI and motor evoked potentials NeuroImage 2004; 21(4): 1805
Ruohonen, J. Karhu, J. Navigated transcranial magnetic stimulation Neurophysiologie clinique 2010 ; 40 (1): 7