Radiofrequency ablation catheter with optical tissue evaluation

Abstract

Systems and methods for performing RF ablation while monitoring the procedure using low coherence interferometry (LCI) data are described. A catheter includes a distal section, a proximal section, a multiplexer, and a sheath coupled between the distal section and the proximal section. The distal section includes one or more electrodes configured to apply RF energy to a portion of a sample in contact with the electrode. The distal section also includes a plurality of optical elements configured to transmit one or more beams of exposure radiation away from the distal section of the catheter. The proximal section includes an optical source configured to generate a source beam of radiation and a detector configured to generate depth-resolved optical data. The multiplexer is configured to generate the one or more beams of exposure radiation from the source beam of radiation.

What is claimed is: 
     
         1 . A method, comprising:
 transmitting exposure radiation along scan lines in different directions via corresponding viewports disposed at a distal end of a catheter, wherein each of the scan lines intersects different locations on a sample;   receiving scattered radiation from the different locations of the sample at corresponding ones of the viewports and along corresponding ones of the scan lines;   guiding the received scattered radiation using optical elements, wherein each of the optical elements corresponds to a respective one of the viewports;   generating depth-resolved optical data of the sample based on the received scattered radiation from the different locations of the sample;   determining a composition of the sample based on the depth-resolved optical data, wherein the composition comprises tissue; and   determining a distance between the distal end and the tissue based on the depth-resolved optical data.   
     
     
         2 . The method of  claim 1 , wherein the composition further comprises blood. 
     
     
         3 . The method of  claim 1 , wherein the composition further comprises saline. 
     
     
         4 . The method of  claim 1 , further comprising:
 generating one or more optical coherence tomography images of the sample based on an analysis of a portion of the scattered radiation, the portion being associated with a sweeping of the catheter.   
     
     
         5 . The method of  claim 4 , wherein the one or more optical coherence tomography images comprise refractivity information of the tissue. 
     
     
         6 . The method of  claim 1 , wherein a phase of radiation transmitted via a first one of the viewports is different from a phase of radiation transmitted via a second one of the viewports. 
     
     
         7 . The method of  claim 1 , further comprising analyzing initial ones of the scattered radiation received at the corresponding ones of the viewports, wherein the determining the distance is further based on the analyzing. 
     
     
         8 . The method of  claim 1 , further comprising analyzing polarization states of the exposure radiation and the received scattered radiation, wherein the determining the distance is further based on the analyzing. 
     
     
         9 . The method of  claim 1 , further comprising determining an impedance at an interface of the distal end and the tissue based on the depth-resolved optical data. 
     
     
         10 . The method of  claim 1 , further comprising ablating the sample using RF energy from one or more electrodes at the distal end. 
     
     
         11 . The method of  claim 10 , further comprising determining a state of continuous contact during the ablating based on the depth-resolved optical data. 
     
     
         12 . The method of  claim 10 , further comprising determining a state of relative motion between the distal end and the tissue during the ablating based on the depth-resolved optical data. 
     
     
         13 . The method of  claim 12 , further comprising generating a notification signal of slippage and/or loss of contact between the distal end and the tissue during the ablating. 
     
     
         14 . The method of  claim 1 , wherein the optical elements comprise optical fibers. 
     
     
         15 . A catheter comprising:
 a distal portion comprising:
 viewports configured to:
 transmit exposure radiation along scan lines in different directions, wherein each of the scan lines intersects different locations on a sample; and 
 receive scattered radiation from the different locations of the sample at corresponding ones of the viewports and along corresponding ones of the scan lines; 
 
 optical elements configured to configured to guide the received scattered radiation, wherein each of the optical elements corresponds to a respective one of the viewports; 
   a proximal portion comprising:
 an illumination system configured to generate the exposure radiation; and 
 a detector configured to generate depth-resolved optical data based on the received scattered radiation; and 
   a processing device configured to:
 determine a composition of the sample based on the depth-resolved optical data, wherein the composition comprises tissue; and 
 determine a distance between the distal portion of the catheter and the tissue based on the depth-resolved optical data. 
   
     
     
         16 . The catheter of  claim 15 , wherein the processor is further configured to generate one or more optical coherence tomography images of the sample based on an analysis of a portion of the scattered radiation, the portion being associated with a sweeping of the catheter. 
     
     
         17 . The catheter of  claim 15 , wherein a phase of radiation transmitted via a first one of the viewports is different from a phase of radiation transmitted via a second one of the viewports. 
     
     
         18 . The catheter of  claim 15 , wherein the distal portion further comprises one or more electrodes configured to ablate the sample using RF energy. 
     
     
         19 . The catheter of  claim 18 , wherein the processing device is further configured to determine, during ablation, at least one of a state of continuous contact or relative motion between the distal portion and the tissue based on the depth-resolved optical data. 
     
     
         20 . The catheter of  claim 15 , wherein the optical elements comprise optical fibers.