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Isopower maps of the electrogastrogram (EGG) after total gastrectomy or total colectomy
S Homma1, J Hasegawa, T Maruta
1Department of Physiology and Surgery, Niigata University School of Medicine, Niigata 951, Japan.
Neurogastroenterology and Motility
|December 3, 1999
Summary
Topographic electrogastrograms (EGG) reveal distinct spectral frequency patterns. Post-gastrectomy or colectomy significantly alters these EGG patterns, particularly for 3 and 6 cpm frequencies, indicating their association with gastric and colonic activity.
Area of Science:
- Medical Imaging
- Gastroenterology
- Physiology
Background:
- Electrogastrograms (EGG) provide topographic mapping of spectral frequencies on the abdominal surface.
- Previous studies have not fully elucidated the correlation between specific EGG frequency bands and gastrointestinal organ activity.
Purpose of the Study:
- To compare pre-operative isopower EGG maps with post-operative maps following total gastrectomy or colectomy.
- To identify the localization and significance of EGG spectral frequency foci in relation to gastric and colonic activity.
Main Methods:
- Simultaneous EGG recordings at 27 epigastro-abdominal locations.
- Spectral analysis using the maximal entropy method (MEM) and calculation of ensemble means.
- Creation of isopower EGG maps using contour mapping based on maximal power peaks and electrode coordinates.
Main Results:
- Pre-operative 1, 8, and 10 cpm foci were evenly distributed.
- 3 and 6 cpm foci, concentrated in the epigastric region, were absent post-gastrectomy.
- Infra-umbilical 3 and 6 cpm foci disappeared after total colectomy.
- Pre-operative maximal power of 3 cpm foci significantly decreased after gastrectomy.
Conclusions:
- EGG frequency bands, specifically 3 and 6 cpm, correlate with gastric and colonic activity, respectively.
- Topographic EGG mapping is a valuable tool for assessing the functional impact of gastrointestinal surgery.