Apparatus and method for assessing tissue treatment

Abstract

The invention relates to a tissue monitoring apparatus, a tissue monitoring method and an ablation lesion monitoring, measuring, and controlling automated algorithm incorporating diffuse reflectance spectroscopy (DRS) and/or Arrhenius model thermal denaturation kinetics for determining the characteristics of the lesion or the tissue, especially for identifying the transmurality of the ablation lesion. The invention pertains to a device for and method of real time monitoring of lesion formation as ablation is being carried out.

I claim: 
     
         1 . A diagnostic apparatus comprising:
 a catheter comprising an elongated body member having a proximal portion and a distal portion,
 a diagnostic assembly on the distal portion, 
 the diagnostic assembly including:
 an optical emitting element, the optical emitting element configured to emit optical radiation into a first tissue portion, 
 an optical receiving element configured to collect optical radiation, the optical radiation indicating characteristics of the first tissue portion; 
 wherein the optical receiving element and the optical emitting element are arranged to be spatially offset along the first tissue portion by at least 5 mm; and 
 
   a processing element electrically or optically connected to the optical receiving element and configured to process the optical radiation collected by the optical receiving element using spatially offset diffuse reflectance spectroscopy.   
     
     
         2 . The apparatus of  claim 1  further comprising a first aperture wherein the optical emitting element is configured to emit optical radiation through a first aperture into the first tissue portion. 
     
     
         3 . The apparatus of  claim 2 , further comprising a second aperture, wherein the optical receiving element collects radiation that enters through the second aperture. 
     
     
         4 . The apparatus of  claim 1 , wherein the distal portion comprises a basket assembly, the basket assembly comprising a plurality of radially expanding splines adapted to position a first radially expanding spline adjacent the first tissue portion, the first radially expanding spline including the diagnostic assembly. 
     
     
         5 . The apparatus of  claim 4 , further comprising a second radially expanding spline with a longitudinal axis, the second radially expanding spline comprising a second diagnostic assembly, the second spline being adapted to position the second diagnostic assembly adjacent a second tissue portion, the second diagnostic assembly comprising:
 a second optical emitting element, the second optical emitting element configured to emit optical radiation into the second tissue portion,   a second optical receiving element configured to collect optical radiation, the optical radiation indicating characteristics of the second tissue portion during the application of energy to the second tissue portion;   wherein the second optical receiving element and the second optical emitting element are arranged to be spatially offset along the second longitudinal axis of the second radially expanding spline.   
     
     
         6 . The apparatus of  claim 1  further comprising an optical fiber displacement actuator configured to adjust the spatial offset between the optical receiving element and the optical emitting element along the first tissue portion such that the spatial offset between the optical receiving element and the optical emitting element is adjustable. 
     
     
         7 . The apparatus of  claim 1 , further comprising an electrode configured to apply energy to the first tissue portion. 
     
     
         8 . The apparatus of  claim 1 , wherein the processing element is configured to generate an optical spectra of the optical radiation collected by the optical receiving element. 
     
     
         9 . The apparatus of  claim 8 , wherein the processing element is configured to compare the generated optical spectra of the optical radiation collected by the optical receiving element to a reference optical spectra for at least one of following tissue types: fat, nerve, muscle, or collagen. 
     
     
         10 . The apparatus of  claim 9 , wherein the processing element is configured to determine that the first tissue portion is at least one of the following tissue types: fat, nerve, muscle, or collagen based at least on the comparison between the generated optical spectra and the reference optical spectra. 
     
     
         11 . The apparatus of  claim 8 , wherein the processing element is configured to compare the generated optical spectra of the optical radiation collected by the optical receiving element to a reference optical spectra for tissue fluid. 
     
     
         12 . The apparatus of  claim 8 , wherein the processing element is configured to automatically calculate a rate of denaturation of the tissue. 
     
     
         13 . The apparatus of  claim 12 , wherein the processing element is configured to extract a rate constant for the rate of denaturation when the tissue is sixty three percent denatured. 
     
     
         14 . The apparatus of  claim 13 , wherein the denaturation is a heat denaturation, a cold denaturation, an electric field denaturation, or a mechanical denaturation. 
     
     
         15 . The apparatus of  claim 1 , wherein the spatial offset between the optical receiving element and the optical emitting element is at least 10 mm. 
     
     
         16 . The apparatus of  claim 5 , wherein the apparatus further comprises an optical radiation source connected to the catheter, the optical radiation source configured to provide optical radiation to the first and the second optical emitting elements such that the first and the second optically emitting elements substantially simultaneously emit optical radiation. 
     
     
         17 . The apparatus of  claim 5 , wherein the apparatus further comprises an optical radiation source in the catheter, the optical radiation source configured to emit optical radiation from one or more apertures. 
     
     
         18 . The system of  claim 1  further comprising a spatial offset displacement insert configured to adjust the spatial offset between the optical receiving element and the optical emitting element along the first longitudinal axis such that the spatial offset between the optical receiving element and the optical emitting element is adjustable. 
     
     
         19 . The apparatus of  claim 1 , wherein the system determines the characteristics of a lesion, nerve, or tissue based on the optical reflectance from the tissue. 
     
     
         20 . The apparatus of  claim 1 , wherein a processing element identifies when the tissue adjacent to the distal end is transmurally denatured based on a change in the slope of a reflectance curve.