磁共振相控阵射频接收线圈g-factor计算代码

MRI SENSE 并行图像加速重建 g-factor计算方法：

 

 

Matlab代码如下：

function g=gfactor_noise(map,LOSS,Rx,Ry)
% map -> sensitivity matrix
% LOSS -> noise-cov matrix
% Rx, Ry -> acc factor in x,y directions

[mm nn uu]=size(map);
cr=zeros(uu,Rx*Ry);
cf=zeros(uu,1);
for ii=1:mm
    for jj=1:nn
            cf(:)=map(ii,jj,:);
            for xx=1:Rx
                for yy=1:Ry
            cr(:,Ry*(xx-1)+yy)=map(cor_adjust(floor(mm/Rx)*(xx-1)+ii,mm),cor_adjust(floor(nn/Ry)*(yy-1)+jj,nn),:);
                end
            end
            LOSS_INV = inv(LOSS);
            cr11=pinv(cr'*LOSS_INV*cr);
            g(ii,jj)=sqrt((cf'*LOSS_INV*cf).*cr11(1,1));

    end
end

 

function [x_a] = cor_adjust(x,x_len)

if x<=x_len
    x_a = x;
else
    x_a = x - x_len;
    
end

end

 

参考文献：

K. P. Pruessmann et al., “SENSE: Sensitivity encoding for fast MRI,” Magn. Reson. Med., vol. 42, no. 5, pp. 952–962, 1999.