IEEE transactions on bio-medical engineering
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IEEE Trans Biomed Eng · May 1997
RF heating of implanted spinal fusion stimulator during magnetic resonance imaging.
Radio frequency (RF) heating of an implanted spinal fusion stimulator (SpF) during magnetic resonance imaging (MRI) was studied on a full-size human phantom. Heating during MRI scans (GE Signa 4X, 1.5 T) was measured with RF-transparent fiberoptic sensors. With the implant correctly connected, the maximum temperature rises were less than 2 degrees C during the 26 min that the scans were at maximum RF power. ⋯ This study shows that spinal fusion stimulator heating is within the Food and Drug Administration safety guideline of 2 degrees C. However, if a lead wire is broken, it is unsafe during MRI scans. Radiological examinations will be necessary to ensure the integrity of the implant.
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IEEE Trans Biomed Eng · May 1997
Detection, classification, and superposition resolution of action potentials in multiunit single-channel recordings by an on-line real-time neural network.
Determination of single-unit spike trains from multiunit recordings obtained during extracellular recording has been the focus of many studies over the last two decades. In multiunit recordings, superpositions can occur with high frequency if the firing rates of the neurons are high or correlated, making superposition resolution imperative for accurate spike train determination. In this work, a connectionist neural network (NN) was applied to the spike sorting challenge. ⋯ The simulations were used to determine the performances of the NN and a simple matched template filter (MTF), which was used as a basis for comparison. The network performed as well as the MTF in identifying nonoverlapping spikes, and was significantly better in resolving superpositions and rejecting noise. An on-line, real-time implementation of the NN discriminator, using a high-speed digital signal processor mounted inside an IBM-PC, is now in use in six laboratories.