Method for estimating the physiological parameters defining the edema induced upon infusion of fluid from an intraparenchymally placed catheter

Abstract

A method for estimating the physiological parameters defining the edema induced upon infusion of fluid from an intraparenchymally placed catheter including; a) acquisition of patient-specific medical data; b) estimation of pertinent tissue microstructure based on the patient-specific medical data and/or generalized information derived or drawn from one or more of the following: experience, literature, modeling, studies, research, analysis; c) acquisition of information about delivery parameters, and/or delivery device geometry, and/or fluid properties, such as: delivery device trajectory, flow rate, pressure, catheter diameter, catheter profile, fluid viscosity, fluid molecular size; and d) computing a field of values of predicted extracellular volume fraction over the tissue region using the information obtained in (b) and (c). According to a further aspect, a method of infusing or planning and/or monitoring an infusion of a contrast agent such that the distribution of such agent can be detected by means of medical data acquisition (e.g. MRI, CT, x-ray, ultrasound, SPECT, PET) and observing and/or measuring the backflow length along the catheter track.

1 . A method for estimating the physiological parameters defining the edema induced upon infusion of fluid from an intraparenchymally placed catheter including;
 a) acquisition of patient-specific medical data;   b) estimation of pertinent tissue microstructure based on the patient-specific medical data and/or generalized information derived or drawn from one or more of experience, literature, modeling, studies, research, and/or analysis;   c) acquisition of information about delivery parameters, and/or delivery device geometry, and/or fluid properties; and   d) computing a field of values of predicted extracellular volume fraction over the tissue region using the information obtained in (b) and (c).   
     
     
         2 . The method of  claim 1 , wherein the patient-specific medical data includes one or more of MRI, CT, PET, SPECT, and/or x-ray data. 
     
     
         3 . The method of  claim 1 , wherein the tissue microstructure includes information about crossing and intra-voxel directionality of fibers in white matter. 
     
     
         4 . The method of  claim 1 , wherein patient-specific medical data includes one or more of diffusivity of water molecules, capillary permeability, blood flow, and/or blood volume. 
     
     
         5 . The method of  claim 1 , wherein any of the computations include one or more of the following parameters: pore fraction, intracellular volume fraction, extracellular volume fraction, and/or hydraulic conductivity. 
     
     
         6 . The method of  claim 1 , wherein the diffusivity of water molecules within the measurement volume is computed. 
     
     
         7 . The method of  claim 1 , wherein the directionality of extracellular matrix scaffolding with respect to the cellular fiber directions is estimated. 
     
     
         8 . The method of  claim 7 , wherein the tautness or slackness of the extracellular matrix scaffolding is estimated. 
     
     
         9 . The method of  claim 1 , wherein patient-specific medical data and/or generalized information is used to extract regions and/or structures of special relevance to the procedure, including one or more of surfaces, functional areas, nerve fiber tracks, cavities, and/or intracranial structures that influence fluid flow and/or distribution. 
     
     
         10 . The method of  claim 9  wherein the extraction of regions and/or structures is performed automatically or semi-automatically using models and/or algorithms for surface detection and delineation, atlases, anatomical information, and computerized versions thereof. 
     
     
         11 . The method of  claim 1 , wherein a derivation of reference values refer to literature values and/or properties about the target volume and/or the entire measurement volume of the patient specific medical information. 
     
     
         12 . The method of  claim 1 , wherein a derivation of reference values refer to a model for fluid distribution within tissue. 
     
     
         13 . The method of  claim 1 , wherein a derivation of reference values refer to generalized values derived from a database. 
     
     
         14 . The method of  claim 1 , wherein an extracellular volume is measured by using medical images. 
     
     
         15 . The method of  claim 14 , wherein the extracellular volume is measured automatically by using imaging processing algorithms. 
     
     
         16 . The method of  claim 15 , wherein the algorithms are specially adapted to properties of the contrast agents. 
     
     
         17 . The method  claim 1 , wherein the result of extracellular expansion estimation is used to refine an infusion or an infusion plan or the information used within the procedure. 
     
     
         18 . The method of  claim 17 , wherein the refinement is done automatically and is implemented in software. 
     
     
         19 . The method of  claim 1  whereby the information computed is used to estimate the location of points at which migrating cells are likely to settle. 
     
     
         20 . The method of  claim 1 , whereby the expansion of the extracellular volume of tissue is used for one or more of the following:
 i. simulating pressure fields and/or fluid concentration and/or flow parameters,   ii. determining suitability of catheter placement for infusing an agent into tissue, and/or   iii. repeating one or more of the steps of  claim 1  using altered methods and/or devices and/or fluids and/or data.   
     
     
         21 . The method of  claim 1 , wherein the information about delivery parameters, and/or delivery device geometry, and/or fluid properties, includes one or more of delivery device trajectory, flow rate, pressure, catheter diameter, catheter profile, fluid viscosity or fluid molecular size. 
     
     
         22 . A method of planning and/or monitoring an infusion of a contrast agent such that the distribution of such agent can be detected by means of medical data acquisition and observing and/or measuring the backflow length along the catheter track. 
     
     
         23 . The method of  claim 22  wherein, the extracellular volume is measured by using medical images. 
     
     
         24 . The method  claim 23 , wherein the extracellular volume is measured automatically by using imaging processing algorithms. 
     
     
         25 . The method of  claim 22 , wherein the algorithms are specially adapted to properties of the contrast agents. 
     
     
         26 . The method of  claim 22 , wherein the result of extracellular expansion estimation is used to refine the infusion or the infusion planning or the information used within the procedures described in  claims 1  to  13 . 
     
     
         27 . The method of  claim 26 , wherein the refinement is done automatically and is implemented in software. 
     
     
         28 . The method of  claim 22 , wherein the information computed is used to estimate the location of points at which migrating cells are likely to settle. 
     
     
         29 . The method of  claim 22 , wherein the expansion of the extracellular volume of tissue is used for one or more of the following:
 i. simulating pressure fields and/or fluid concentration and/or flow parameters,   ii. determining suitability of catheter placement for infusing an agent into tissue, and   iii. repeating one or more of the steps of  claim 1  using altered methods and/or devices and/or fluids and/or data.   
     
     
         30 . A method of infusing a contrast agent such that the distribution of such agent can be detected by means of medical data acquisition and observing and/or measuring the backflow length along the catheter track. 
     
     
         31 . The method of  claim 30 , wherein extracellular volume is measured by using medical images. 
     
     
         32 . The method  claim 31 , wherein the extracellular volume is measured automatically by using imaging processing algorithms. 
     
     
         33 . The method of  claim 32 , wherein the algorithms are specially adapted to properties of the contrast agents. 
     
     
         34 . The method of  claim 30 , wherein the result of extracellular expansion estimation is used to refine the infusion or the information used within the procedure. 
     
     
         35 . The method of  claim 34 , wherein the refinement is done automatically and is implemented in software. 
     
     
         36 . The method of  claim 30 , wherein the information computed is used to estimate the location of points at which migrating cells are likely to settle. 
     
     
         37 . The method of  claim 30 , wherein the expansion of the extracellular volume of tissue is used for one or more of the following:
 i. Simulating pressure fields and/or fluid concentration and/or flow parameters,   ii. determining suitability of catheter placement for infusing an agent into tissue, and   iii. repeating one or more of the steps of  claim 1  using altered methods and/or devices and/or fluids and/or data.