Method and apparatus for characterization of clot formation

Abstract

Methods, apparatus and systems for characterizing changes in at least one physical properly of soft tissue. A series of acoustic pulses is generated and directed into the soft tissue such that at least one of the pulses is of sufficiently high intensity to induce physical displacement of the tissue. Waves reflected off the tissue, or a flexible member that moves with the tissue, are received and measured to estimate at least one characteristic of the physical displacement induced thereby. Repetition of the generating, receiving and estimating steps provides characterization of the at least one physical property over time. Methods, apparatus and systems for characterizing at least one physical property or blood, by generating a series of acoustic pulses and directing the series of pulses into the blood such that at least one of the pulses is of sufficiently high intensity to induce physical displacement of the blood. Acoustic pulses and/or optical waves reflected from the blood, or a flexible member in contact with the blood that moves with the blood, are received and measured to estimate at least one characteristic of the physical displacement induced thereby.

What is claimed is: 
     
         1 . A method of characterizing at least one property of a biological material, said method comprising:
 testing a first portion of the biological material;   estimating a quantitative value of a property of the first portion;   treating a second portion of the biological material with a treatment to vary a quantitative value of said property from said quantitative value of the property of the first portion having been estimated;   testing the second portion of the biological material having been treated;   estimating a second quantitative value of said property of the second portion;   comparing said first quantitative value with said second quantitative value; and   evaluating an effect of said treating on said property of the biological material.   
     
     
         2 . The method of  claim 1 , wherein said testing a first portion of the biological material and said testing the second portion of the biological material are performed in parallel. 
     
     
         3 . The method of  claim 1 , further comprising:
 treating a third portion of the biological material with a treatment to vary a quantitative value of said property from said first and second quantitative values of the property of the first and second portions having been estimated;   testing the third portion of the biological material having been treated;   estimating a third quantitative value of said property of the third portion;   comparing said third quantitative value with said first and second quantitative values; and   evaluating an effect of said treating on said property of the biological material.   
     
     
         4 . The method of  claim 1 , wherein the biological material is blood. 
     
     
         5 . The method of  claim 4 , wherein said treating comprises treating the second portion of the blood with an anti-clotting or pro-clotting treatment. 
     
     
         6 . The method of  claim 1 , wherein said testing comprises:
 generating a series of acoustic pulses and directing said series of pulses into the biological material such that at least one of the pulses is of sufficiently high intensity to induce physical displacement of the biological material; and   measuring a displacement, either directly or indirectly, of the biological material resulting from said induced physical displacement thereof; and   wherein said estimating is based on said measuring.   
     
     
         7 . The method of  claim 6 , wherein the temperature of the biological material is controlled over a duration of said measuring a displacement. 
     
     
         8 . The method of  claim 6 , further comprising repeating said generating and estimating steps after passage of a time interval. 
     
     
         9 . The method of  claim 8 , wherein said estimating is based on receiving at least two of said acoustic pulses reflected from the biological material and estimating the at least one property based on the acoustic pulses received. 
     
     
         10 . The method of  claim 8 , wherein said estimating is based on receiving optical reflections from the biological material as the biological material is being physically displaced and estimating the at least one property based on the optical reflections received. 
     
     
         11 . The method of  claim 8 , wherein said generating and estimating steps are repeated after passage of each of a plurality of predetermined time intervals. 
     
     
         12 . The method of  claim 8 , wherein said at least one property comprises at least one parameter determined by fitting experimental data including a plurality of said estimates or measurements, to a theoretical model defining the at least one property. 
     
     
         13 . The method of  claim 1 , wherein said at least one property comprises at least one of relative viscosity and relative elasticity of the biological material. 
     
     
         14 . The method of  claim 1 , wherein said at least one property comprises at least one force-free parameter. 
     
     
         15 . The method of  claim 6 , wherein the biological material is blood. 
     
     
         16 . The method of  claim 8 , further comprising receiving at least a portion of said pulses that pass through the biological material and estimating at least one acoustic property of the biological material. 
     
     
         17 . The method of  claim 16 , further comprising estimating a magnitude of applied force of the at least one pulse having sufficiently high intensity to induce physical displacement of the biological material, based upon said at least one estimated acoustic property. 
     
     
         18 . The method of  claim 16 , wherein said at least one acoustic property comprises at least one of attenuation and speed of sound.