Patent ID: 11927659
Assignee: ZHEJIANG UNIVERSITY
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 4:
5. The method for frequency drift correction of magnetic resonance CEST imaging according to claim 4, the calculation formula of the value Δf of the main magnetic field frequency drift is:, Δ
   ⁢
   f
  
  =
  
   
    
     φ
     ¯
    
    
     2
     -
     1
    
   
   
    2
    ⁢
    
     π
     ·
     Δ
    
    ⁢
    
     TE
     
      2
      -
      1
     
    
   
  
 

where ΔTE2-1 is the sampling time interval of the two lines of non-phase encoding gradient echo signals; φ2-1 is the inter-line phase difference between the two lines of non-phase encoding gradient echo signals, and the calculation formula is:, φ
    _
   
   
    2
    -
    1
   
  
  =
  
   
    
     
      ∑
      
       i
       =
       1
      
      n
     
      
     
      
       φ
       
        2
        -
        1
       
      
      ⁢
      i
     
    
    n
   
   .
  
 

where φ2-1i is the phase difference between respective ith data sampling points of the two lines of non-phase encoding gradient echo signals, n is the number of the sampling points in each line of non-phase encoding gradient echo signals.