Effect of shot number on the calculated apparent diffusion coefficient in phantoms and in human liver in diffusion-weighted echo-planar imaging

2009 ◽  
Vol 30 (3) ◽  
pp. 547-553 ◽  
Author(s):  
Masoud Shiehmorteza ◽  
Claude B. Sirlin ◽  
Tanya Wolfson ◽  
Anthony Gamst ◽  
Andre E. Soumekh ◽  
...  
2014 ◽  
Vol 4 (2) ◽  
pp. 517-525
Author(s):  
Cristiano Biagini ◽  
Martina De Michele ◽  
Andrea Pratesi ◽  
Francesco Mungai ◽  
Margherita Betti ◽  
...  

Purpose: To define experimental grounds for Apparent Diffusion Coefficient (ADC) measurements using Spin-Echo Diffusion-Weighted Echo-Planar (SE-DW-EPI) sequences, as a function of Signal-to-Noise Ratio (SNR).Methods: multiple multi-b SE-DW-EPI scans with the same parameters but the lipid suppression technique have been compared on water phantom with a 3T MRI equipment. The SNR has been estimated using the method of difference. Images have been analyzed manually, comparing the signal intensities at different b-values.Results: All measurements show a high repeatability and strong self-consistency. A significant dependence of the ADC on SNR has been shown, and its lowest limitto obtain reliable quantitative answers has been stated.Conclusion: ADC measurements in vivo must be carefully designed to avoid systematic errors during acquisition and post-processing due to low SNR.


1998 ◽  
Vol 39 (4) ◽  
pp. 440-442 ◽  
Author(s):  
Y. Amano ◽  
T. Kumazaki ◽  
M. Ishihara

Single-shot spin-echo diffusion-weighted echo-planar imaging using a phased-array multicoil was performed to distinguish between normal and cirrhotic livers. Sets of 6 images with different b-values were acquired with breathholding. Significant differences were observed between controls and cirrhosis cases in the signal ratios when the b-value was 383 s/mm2, and apparent diffusion coefficients.


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