EIDORS: Electrical Impedance Tomography and Diffuse Optical Tomography Reconstruction Software

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Using EIDORS to image lungs

2D EIT for lung imaging

% Lung images
% $Id: tutorial310a.m 1535 2008-07-26 15:36:27Z aadler $

% 2D Model
imdl= mk_common_model('c2t2',16);

% Make correct stimulation pattern
[st, els]= mk_stim_patterns(...
   16, ... % electrodes / ring
    1, ... % 1 ring of electrodes
   '{ad}','{ad}', ... % adj stim and measurement
   { 'no_meas_current', ... %  don't mesure on current electrodes
     'no_rotate_meas',  ... %  don't rotate meas with stimulation
     'do_redundant', ...    %  do redundant measurements
   }, 10 );  % stimulation current (mA)
imdl.fwd_model.stimulation= st;
imdl.fwd_model.meas_select= els;

% most EIT systems image best with normalized difference
imdl.fwd_model.normalize_measurements= 1;
imdl.RtR_prior= @gaussian_HPF_prior;


subplot(221);
show_fem(imdl.fwd_model);

axis equal
print -r100 -dpng tutorial310a.png;

Figure: 2D FEM of thorax (units in mm). Electrode #1 (o) and electrode #2 (o) are shown in different colours than the others (o).

% Lung images
% $Id: tutorial310b.m 1535 2008-07-26 15:36:27Z aadler $

% If electrodes are counter-clockwise, then do this
imdl_ccw = imdl;
imdl_ccw.fwd_model.electrode([1,16:-1:2])=  ...
   imdl.fwd_model.electrode;

subplot(221);
show_fem(imdl_ccw.fwd_model);

% If electrodes start on back (dorsal), then do this
imdl_d = imdl;
imdl_d.fwd_model.electrode([9:16,1:8])=  ...
   imdl.fwd_model.electrode;

subplot(222);
show_fem(imdl_d.fwd_model);

axis equal
print -r100 -dpng tutorial310b.png;

Figure: Left: electrodes placed counter-clockwise starting at 12 O'clock. Right: electrodes placed clockwise starting at 6 O'clock (on the dorsal side)

% Lung images
% $Id: tutorial310c.m 1535 2008-07-26 15:36:27Z aadler $

load montreal_data_1995
imdl_d.hyperparameter.value=5e-2;
img= inv_solve(imdl_d, zc_resp(:,22), zc_resp);

clf; show_slices(img)
axis equal

print -r100 -dpng tutorial310c.png;

Figure: Lung image slices (frame rate of 1/7 seconds). Image progression is from left to right, top to bottom. One breath is shows. There also appears to be a movement of blood dorsally during the cardiac cycle.