Mri compatible medical leads with band stop filters

Abstract

Herein is disclosed an MRI compatible medical lead with band stop filters in communication with a respective lead conductor and electrode tuned to resonate at selected (MRI) high frequencies.

1 . An MRI compatible medical diagnostic or therapeutic device, comprising:
 a medical device including a lead wire extending therefrom, the device adapted for contact with biological cells; and   a band stop filter associated with the lead wire for attenuating current flow through the lead wire at a selected frequency or frequency band, wherein the band stop filter comprises a capacitor in parallel with an inductor, said parallel capacitor and inductor placed in series with the lead wire, wherein values of capacitance and inductance are selected such that the band stop filter is resonant at the selected frequency or frequency band.   
     
     
         2 . The device of  claim 1 , wherein the band stop filter attenuates current flow through the lead wire at selected MRI frequencies. 
     
     
         3 . The device of  claim 1 , wherein the band stop filter is proximate an implantable electrode. 
     
     
         4 . A process for attenuating current flow through a lead wire for a medical device at a selected frequency, comprising the steps of:
 selecting a capacitor which is resonant at the selected frequency; selecting an inductor which is resonant at the selected frequency;   using the capacitor and the inductor to form a tank filter circuit; and   placing the tank filter circuit in series with the lead wire.   
     
     
         5 . The process of  claim 4 , including the step of configuring the tank filter circuit to attenuate current flow through the lead wire along a range of selected frequencies. 
     
     
         6 . The process of  claim 4 , wherein the range of selected frequencies includes a plurality of MRI pulse frequencies. 
     
     
         7 . The process of  claim 4 , including the step of disposing the tank filter circuit at the distal end portion of the lead wire. 
     
     
         8 . The process of  claim 6 , including the step of placing the tank filter circuit proximate an electrode. 
     
     
         9 . The process of  claim 8 , wherein the electrode is held by a probe or catheter. 
     
     
         10 . A medical device comprising:
 a probe or catheter having electrodes adapted to contact biological cells and at least one conductor in communication with each electrode; and   at least one band stop filter associated with the electrodes for attenuating current flow through the probe or catheter at a selected frequency or frequency range, wherein the band stop filter comprises a capacitor in parallel with an inductor, said parallel capacitor and inductor placed in series with at least one of the electrodes, wherein the band stop filter is resonant at the selected frequency or frequency range, and wherein the band stop filter is configured to attenuate current flow through the conductors at the selected frequency or frequency range.   
     
     
         11 . The device of  claim 10 , wherein the range of selected frequencies includes a plurality of MRI pulse frequencies.