Optimal windows for obtaining optical data for characterization of tissue samples

Abstract

The invention provides methods for determining a characteristic of a tissue sample, such as a state of health, using spectral data and/or images obtained within an optimal period of time following the application of a chemical agent to the tissue sample. The invention provides methods of determining such optimal windows of time. Similarly, the invention provides methods of determining other criteria for triggering the acquisition of an optical signal for classifying the state of health of a region of a tissue sample.

What is claimed is:  
     
         1 - 15  (cancelled)  
     
     
         16 . A method of identifying a characteristic of a region of a tissue sample, the method comprising the steps of: 
 (a) applying a contrast agent to a region of a tissue sample;    (b) obtaining at least one reflectance signal from the region of the tissue sample within a window of time, wherein the window of time begins at about 30 seconds following application of the contrast agent and ends at about 130 seconds following application of the contrast agent;    (c) obtaining a fluorescence signal from the region of the tissue sample within the window of time; and    (d) identifying a characteristic of the region based at least in part on the fluorescence signal and at least one of the at least one reflectance signals.    
     
     
         17  The method of  claim 16 , the method further comprising the step of obtaining a video signal from the region of the tissue sample within the window of time.  
     
     
         18  The method of  claim 17 , wherein step (d) comprises identifying a characteristic of the region based at least in part on the fluorescence signal, at least one of the at least one reflectance signals, and the video signal.  
     
     
         19  The method of  claim 16 , wherein step (b) comprises obtaining two reflectance signals from the region of the tissue sample within the window of time.  
     
     
         20 - 41  (cancelled)  
     
     
         42  The method of  claim 16 , wherein the characteristic is a state of health.  
     
     
         43  The method of  claim 42 , wherein the state of health comprises at least one of the group consisting of normal squamous tissue, normal columnar tissue, metaplasia, immature metaplasia, mature metaplasia, CIN1, CIN2, CIN3, CIS, and cancer.  
     
     
         44  The method of  claim 16 , wherein the identifying step (d) comprises determining whether the region of the tissue sample is CIN 2+ tissue.  
     
     
         45  The method of  claim 16 , wherein the contrast agent comprises acetic acid.  
     
     
         46  The method of  claim 16 , wherein the contrast agent is selected from a group consisting of formic acid, propionic acid, butyric acid, Lugol's iodine, Shiller's iodine, methylene blue, toluidine blue, indigo carmine, indocyanine green, and fluorescein.  
     
     
         47  The method of  claim 16 , wherein the tissue sample comprises cervical tissue.  
     
     
         48  The method of  claim 16 , wherein the tissue sample comprises at least one of a group consisting of colorectal tissue, gastroesophageal tissue, urinary bladder tissue, lung tissue, and skin tissue.  
     
     
         49  The method of  claim 16 , wherein the tissue sample comprises epithelial cells.  
     
     
         50  The method of  claim 16 , wherein step (b) comprises obtaining the at least one reflectance signal from the region within a period of time that begins at about 60 seconds following application of the contrast agent and ends at about 80 seconds following application of the contrast agent.  
     
     
         51  The method of  claim 16 , wherein step (b) comprises obtaining the at least one reflectance signal from the region within a period of time that begins at about 70 seconds following application of the contrast agent and ends at about 130 seconds following application of the contrast agent.  
     
     
         52  The method of  claim 16 , wherein step (d) comprises identifying the characteristic of the region with an accuracy of at least about 70%.  
     
     
         53  The method of  claim 16 , wherein step (b) comprises obtaining a reflectance intensity from the region at each of a plurality of wavelengths within the window of time.  
     
     
         54  The method of  claim 16 , wherein step (c) comprises obtaining a fluorescence intensity from the region at each of a plurality of wavelengths within the window of time.  
     
     
         55  The method of  claim 54 , wherein step (d) further comprises obtaining a video signal from the region within the window of time.  
     
     
         56  The method of  claim 16 , wherein step (a) comprises applying a contrast agent to a plurality of regions of the tissue sample; step (b) comprises obtaining at least one reflectance signal from each of the plurality of regions within the window of time; step (c) comprises obtaining a fluorescence signal from each of the plurality of regions within the window of time; and step (d) comprises identifying a characteristic of each of the plurality of regions.  
     
     
         57  The method of  claim 16 , wherein step (d) comprises identifying a characteristic of the region based substantially on at least one optical signal, obtained within the window of time.  
     
     
         58  The method of  claim 16 , wherein the window of time begins at 20 seconds following application of the contrast agent.