are ventilated the lung in fig3 is a copd lung which is ventilated with great offset in time because of different regional resistivities and elasticities the dorsal regions are ventilated earlier than the ventral ones but the pattern of the local image element curves 5 still agrees essentially with the averaged impedance curve 4 so that the correlations are still always rather close at nearly 80 to 100 the cross correlation curves not shown all have their maxima at 100 fig4 shows an animal experiment with a lung artificially damaged with hydrochloric acid the curves or time series of the image elements in the central right and left lung area with the numbers 1 and 2 show excellent correlation with the mean impedance change curve with correlations of 100 whereas the impedance change curves of the image elements 3 and 4 in the dorsal right and left lung areas show slight but significant relative impedance changes which run counter to the ventilation while the impedance otherwise increases during the supply of air it drops there significantly the correlations are consequently u2212 80 to u2212 95 these are not overshoots whose correlation would equal u2212 100 and thus would also occur at other locations it is reasonable to suspect that this characteristic is linked with the damaged lung in the dorsal area regardless of the exact cause of the anticorrelating characteristic no ventilation takes place here the correlation coefficients c mi selected as deviation indicators here are compared for all image elements selected through the mask with a threshold c thr a threshold of c thr.