Patent ID: 11901081
Assignee: SUZHOU RAINMED MEDICAL TECHNOLOGY CO., LTD.
Field: Medical technology (Instruments)
Classification: CPC G  A | IPC G

Claim 7:
8. The method for calculating an index of microcirculatory resistance based on myocardial blood flow and CT image according to claim 1, wherein step S07 comprises:
based on the geometric structure reconstructed by CT, straightening blood vessel with stenosis, constructing a two-dimensional axisymmetric model, dividing two-dimensional grids, and solving a continuity and Navier-Stokes equation by numerical methods:, 1
        r
       
       ⁢
       
        
         ∂
         
          ∂
          r
         
        
        
         (
         
          r
          ⁢
          
           u
           r
          
         
         )
        
       
      
      +
      
       
        ∂
        
         u
         z
        
       
       
        ∂
        z
       
      
     
     =
     0
    
   
   
    
     [
     A3
     ]
    
   
  
 

 
  
   
    
     
      ρ
      ⁢
      
       (
       
        
         
          ∂
          
           u
           r
          
         
         
          ∂
          t
         
        
        +
        
         
          u
          r
         
         ⁢
         
          
           ∂
           
            u
            r
           
          
          
           ∂
           r
          
         
        
        +
        
         
          u
          z
         
         ⁢
         
          
           ∂
           
            u
            r
           
          
          
           ∂
           z
          
         
        
       
       )
      
     
     =
     
      
       -
       
        
         ∂
         p
        
        
         ∂
         r
        
       
      
      +
      
       μ
       [
       
        
         
          1
          r
         
         ⁢
         
          
           ∂
           
            ∂
            r
           
          
          
           (
           
            r
            ⁢
            
             
              ∂
              
               u
               r
              
             
             
              ∂
              r
             
            
           
           )
          
         
        
        +
        
         
          
           ∂
           2
          
          
           u
           r
          
         
         
          ∂
          
           z
           2
          
         
        
        -
        
         
          u
          r
         
         
          r
          2
         
        
       
       ]
      
     
    
   
   
    
     [
     A4
     ]
    
   
  
 

 
  
   
    
     
      ρ
      ⁢
      
       (
       
        
         
          ∂
          
           u
           z
          
         
         
          ∂
          t
         
        
        +
        
         
          u
          r
         
         ⁢
         
          
           ∂
           
            u
            z
           
          
          
           ∂
           r
          
         
        
        +
        
         
          u
          z
         
         ⁢
         
          
           ∂
           
            u
            z
           
          
          
           ∂
           z
          
         
        
       
       )
      
     
     =
     
      
       -
       
        
         ∂
         p
        
        
         ∂
         z
        
       
      
      +
      
       μ
       [
       
        
         
          1
          r
         
         ⁢
         
          
           ∂
           
            ∂
            r
           
          
          
           (
           
            r
            ⁢
            
             
              ∂
              
               u
               z
              
             
             
              ∂
              r
             
            
           
           )
          
         
        
        +
        
         
          
           ∂
           2
          
          
           u
           z
          
         
         
          ∂
          
           z
           2
          
         
        
       
       ]
      
     
    
   
   
    
     [
     A5
     ]
    
   
  
 

wherein, ρ represents the density of blood, uz and ur represent the flow velocity in the z direction and r direction, respectively, μ represents the dynamic viscosity of the blood, and p represents the pressure of the blood;
an inlet boundary condition being: the inlet flow velocity V1 of the coronary artery stenosis vessel in the maximum hyperemia state;
calculating a pressure drop of each coronary artery stenosis through two-dimensional computational fluid dynamics to obtain ΔP1, ΔP2, ΔP3 . . . , calculating the pressure drop from the coronary artery inlet to the distal end of the coronary artery stenosis using ΔP=ΣΔPi (i=1, 2, 3 . . . ), and obtaining the mean intracoronary pressure Pd at the distal end of the stenosis using Pd=Pa−ΔP, wherein Pa is the mean aortic pressure.