We report a novel method for identifying the small intestine electrical activity slow wave frequencies from noninvasive biomagnetic measurements. Superconducting QUantum Interference Device (SQUID) magnetometer measurements are pre-processed to remove baseline drift and high frequency noise. Subsequently, the underlying source signals are separated using the well-known SOBI algorithm. A simple classification scheme identifies and assigns some of the SOBI components to a section of small bowel. Slow wave frequencies were clearly identified in 10 out of 12 test subjects to within 0.09-0.25 cycles per minute. The method is sensitive at the 40.3-55.9% level, while false positive rates were 0-8.6%. This technique could potentially be used to help diagnose gastrointestinal ailments and obviate some exploratory surgeries.

We report a robust method for noninvasive biomagnetic detection of small bowel electrical activity. Simultaneous Superconducting QUantum Interference Device (SQUID) magnetometer (MENG) and serosal electrode recordings were made on pig small bowel. The SOBI blind-source separation algorithm was used to separate the underlying source signals of the MENG. Comparison of identified SOBI components to the serosal recordings validated the underlying MENG sources as being enteric in origin. Non-invasive detection of small bowel electrical activity could have significant implications in a clinical setting.