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EIDORS: Electrical Impedance Tomography and Diffuse Optical Tomography Reconstruction Software

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PEEP trial after lung injury (pig)

Methods and Data

Use mk_common_model to create a thorax shaped model with 16 electrodes. Ensure the model uses 1) Correct stimulation patterns (adjacent is default), 2) Normalized difference imaging

Methods and Data

Five pigs before (e.g. 1-control.raw) and after induction of unilateral lung injury (e.g. 1-injury.raw). Oleic acid was administered through the distal opening of a pulmonary artery catheter placed in a branch of the left pulmonary artery.

Data were published in:
I. Frerichs, G. Hahn, T. Schröder, G. Hellige Electrical impedance tomography in monitoring experimental lung injury Intensive Care Med. 24:829-836, 1998.

Results

The key results are shown in Fig.3 from the paper
figure 3
Figure 3 (from Frerichs et al, 1998): Thoracic functional EIT images before (Control) and after the development of artificially induced left lung injury (Lung injury) reflecting the distribution of ventilation in the five animals studied. (The lungs are typically located in the central and ventral parts of the thorax due to the well developed backbone musculature in pigs.) The schematic cross-section of the pig thorax in the left upper corner shows the spatial orientation of the images. Each image is scaled to the individual maximum impedance variation. The scale shows that higher local impedance variation (i.e. higher fluctuation of regional lung volume) is represented in light tones

EIDORS Analysis

  1. Download the data and save it to your working directory.
  2. Create a FEM model of the pig
    % Create Model $Id: if_lung_injury01.m 3341 2012-07-01 21:26:50Z bgrychtol $
    
    imdl= mk_common_model('c2c2',16);
    % Reverse electrodes to give 'clinical' view (looking toward patient head)
    imdl.fwd_model.electrode =  ...
       imdl.fwd_model.electrode([9:-1:1,16:-1:10]);
    % Use normalized difference imaging
    imdl.fwd_model = mdl_normalize(imdl.fwd_model, 1);
    
    subplot(211);
    show_fem(imdl.fwd_model, [0,1,0]);
    axis equal; axis off
    
    hh=text(-1.15,0,'Right');
    set(hh,'Rotation',90,'HorizontalAlignment','Center');
    hh=text(0,+1.15,'Ventral');
    set(hh,'HorizontalAlignment','Center');
    
    print_convert if_lung_injury01.png 
    
    

    Figure: 2D FEM of pig thorax
  3. Analyse and show data
    subplot(221);
    for loop1= 1:5;
           
      for loop2 = 1:2;
         if loop2 ==1; fn = sprintf('%d-control.RAW',loop1);
         else          fn = sprintf('%d-injury.RAW',loop1);
         end
    
         prname= sprintf('if_lung_injury02-%d%d.png', loop1,loop2);
    
         dd= eidors_readdata(fn);
    
         img=inv_solve(imdl,mean(dd,2),dd);
         [jnk,fmin] = min(mean(img.elem_data,1)); % find end-inspi
         [jnk,fmax] = max(mean(img.elem_data,1)); % find end-expi
    
         img=inv_solve(imdl,dd(:,fmax), dd(:,fmin));
         show_slices(img);
    
         print_convert(prname,'-density 50');
       end
    end
    
    
    Pig #1 Pig #2 Pig #3 Pig #4 Pig #5
    Control
    Left
    Lung
    Injury

    Figure: Images of Tidal Ventilation in Pigs

Last Modified: $Date: 2017-02-28 13:12:08 -0500 (Tue, 28 Feb 2017) $ by $Author: aadler $