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    Theoretic Basis and Technical Implementations of CT Perfusion in Acute Ischemic Stroke, Part 2: Technical Implementations | American Journal of Neuroradiology  
    


















    





















    
  
  




    
    

  

      


    

      

  
  
  

    

  

    

  

                
    

      

  

    

  
      
  
  

    


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OtherPHYSICS REVIEW

  
      

  
      
Theoretic Basis and Technical Implementations of CT Perfusion in Acute Ischemic Stroke, Part 2: Technical Implementations
  
    	
A.A. Konstas, G.V. Goldmakher, T.-Y. Lee and M.H. Lev

  
    	
American Journal of Neuroradiology May 2009,  30 (5) 885-892; DOI: https://doi.org/10.3174/ajnr.A1492 

  
  
  



  


  
  



			

		

	
	
 	
	  
  

		
		

			

			  

  
      
  
  

    
  


  
  



  
      
  
  

    

  

    

  
        
Article Figures & Data

    
  
  

    
Figures
  • Fig 1.
    Fig 1. 
    The maximum slope method. CBF can be calculated from the ratio of the maximum slope (Max Slope) of Q(t) to the maximum arterial concentration. The higher maximum slope in the contralateral region of interest (ROI) (ie, the region of interest without stroke) will give a higher CBF than that for the ipsilateral region of interest, for which the CBF will be reduced.
  • Fig 2.
    Fig 2. 
    A−H, CTP maps calculated by using a delay-sensitive deconvolution algorithm that is affected by the delay (To) between arterial input and tissue curves. To simulate a range of To, we processed the dynamic images of a single section from a CTP study on a patient with brain tumor such that time-versus-enhancement curves from the entire left hemisphere were shifted forward in time by 2 seconds relative to the right hemisphere. The original and time-shifted CTP studies were then processed by Perfusion 3 (GE Healthcare) by using the same arterial input curve and venous curve from the right hemisphere. A and B, CBF maps for the original and the To = 2 second study. C and D, The corresponding CBV maps. E and F, The corresponding MTT maps. G and H, The corresponding To maps. As To increases, CBF decreases and MTT increases while CBV remains unchanged. The deconvolution algorithm is not able to estimate To. I−P, CTP maps calculated by using a delay-insensitive deconvolution algorithm that is unaffected by the To between arterial input and tissue curves. The original and time-shifted CTP studies of I−P are processed in the same way as A−H except that a delay-insensitive deconvolution algorithm (Perfusion 4, GE Healthcare) is used instead. I and J, The CBF maps for the original and To = 2 second study. K and L, The corresponding CBV maps. M and N, The corresponding MTT maps. O and P, The corresponding To maps. As To increases, CBF and CBV remain relatively unchanged and MTT increases slightly. The deconvolution algorithm is able to detect an increase in To, but the estimate of To is not accurate.
Tables
  • Table 1: 
    Sample acute stroke protocol for 64-section MDCT scanner: NCCT, vertex-to-arch CTA with cardiac component, and standard cine CTP
    LocationSection Thickness (mm)Image Spacing (mm)PitchkVmAGantry Rotation Time (s)Contrast Administration
    NCCTC1 to vertex550.531:11202500.7
    CTAVertex to 1 cm below carina1.250.6250.516:11204200.54 mL/s; volume, 40-mL contrast
    CardiacCarina to just below diaphragm0.6250.6251:11204200.35Repeat after 45-second delay
    Cine CTPSelected by neuroradiologist4-cm slabN/AN/A8020017 mL/s; volume, 35 mL
    • Note:—NCCT indicates noncontrast CT; N/A, not applicable; MDCT, multidector row CT; CTA, CT angiography; CTP, CT perfusion .
  • Table 2: 
    Sample acute stroke protocol for 64-section MDCT scanner: NCCT, vertex-to-arch CTA without cardiac component, and shuttle-mode CTP
    LocationSection Thickness (mm)Image Spacing (mm)PitchkVmAGantry Rotation Time (s)Contrast Administration
    NCCTC1 to vertex550.531:11202500.7
    CTAVertex to 1 cm below carina1.250.6250.516:1120200–6600.54 mL/s; volume, 60-mL contrast
    Shuttle-mode CTPSelected by neuroradiologist8-cm slabN/AN/A805000.47 mL/s; volume, 45 mL
  


  
  



  




  


  
  



  
      
  
  

    
  


  
  



  
      
  
  

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Theoretic Basis and Technical Implementations of CT Perfusion in Acute Ischemic Stroke, Part 2: Technical Implementations
  
    	
A.A. Konstas, G.V. Goldmakher, T.-Y. Lee, M.H. Lev

  
    	
American Journal of Neuroradiology May 2009, 30 (5) 885-892; DOI: 10.3174/ajnr.A1492 

  
  
  



  


  
  



  
      
  
  

    

  
    
  
  
    
  
  
    
  


  


  
  



  
      
  
  

    
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