Figure 6.

Comparison of predicted and measured standard deviations of the sum (top row) and mean (bottom row) of an ROI as it grows along the phase encoding direction in an image with parallel imaging factor 4. The sampling pattern used here sampled lines 1,5,9,…, etc. The solid line is the predicted standard deviation from the proposed method, the dashed line is the calculated standard deviation from 100 repeated experiments, and the dotted line is the calculated standard deviation from 100 pseudo replica reconstructions. The gray dotted line on the magnitude plots indicated the predicted standard deviation when assuming that all pixels are independent, i.e. the standard deviation is calculated based on the g-factor taking parallel imaging associated noise enhancement into consideration.