# Noise in MRI

## Physics

Noise in MRI is created by the fluctuation of voltage from 2 main sources which
are independent of the magnitude of the magnetization and follow a gaussian
distribution with zero mean :

• Patient
• Electronic

Thus the noise observed in the k-space also follow an uncorrelated zero mean gaussian distribution
in both imaginary and real component with a standard deviation $\sigma_G$ :

## Reference papers

(1) Cárdenas-Blanco A, Tejos C, Irarrazaval P, Cameron I. Noise in magnitude magnetic resonance images. Concepts Magn Reson Part A Internet . 2008 Nov;32A(6):409–16. Available from: http://doi.wiley.com/10.1002/cmr.a.20124