Isopower mapping of electrogastrograms in short-bowel syndrome.

Methods for making topographic or isopower electrogastrographic (EGG) maps and for obtaining maximum power foci (MPFs) by means of 27-channel EGG recordings are briefly described. The methods are applied to short-bowel syndrome (SBS). The gastro-intestinal tract is traced by videofluorograms after X-ray-opaque barium has been ingested. The MPFs are generally located on the trace of the gastro-intestinal tract. The gastric area is occupied by 3 cycles x min(-1) (up to 28% of total MPFs) and 6 cycles x min(-1) MPFs (26%). The trace of the small intestine is occupied mainly by 8 cycles x min(-1) (39%) and 10 cycles x min(-1) (43%) MPFs. The trace of the colon is occupied almost evenly by all five spectral frequency groups, that is, by 1 (58%), 3 (53%), 6 (48%), 8 (57%) and 10 cycles x min(-1) (42%). Most interestingly, the numbers of 8-10 cycles x min(-1) power foci found on EGG maps (including MPFs and relatively higher power foci) are proportional to the remaining length at operation and to the length of the remaining small intestine in the long-term, over 6 years postoperatively. It is therefore possible to follow approximately the trace of the gastero-intestinal tract.