Effect of SNR and Thresholding on the Apparent Diffusion Coefficient in Hyperpolarized He-3 MRI
O'Halloran R, Fain S, Holmes J, Altes T
University of Wisconsin
A novel method that applies either automatic or interactive thresholding directly on the SNR of the non-weighted image is presented. With this approach, the mean ADC is largely dependent of image SNR. Also, a theoretical model for the dependence of standard deviation (SD) on SNR is confirmed in a free diffusion phantom. Deviation from purely stochastic SD is demonstrated in the lungs of a smoker with 40 pack years and may provide a means for extracting SNR-independent information about regional variation in lung microstructure.