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. 2019 Jul:239:31-37.
doi: 10.1016/j.jss.2019.01.034. Epub 2019 Feb 20.

Magnetoenterography for the Detection of Partial Mesenteric Ischemia

Suseela Somarajan  1 , Nicole D Muszynski  2 , Joseph D Olson  3 , Leonard A Bradshaw  4 , William O Richards  5
Affiliations

Magnetoenterography for the Detection of Partial Mesenteric Ischemia

Suseela Somarajan et al. J Surg Res. 2019 Jul.

Abstract

Background: Acute mesenteric ischemia represents a life-threatening gastrointestinal condition. A noninvasive diagnostic modality that identifies mesenteric ischemia patients early in the disease process will enable early surgical intervention. Previous studies have identified significant changes in the small-bowel electrical slow-wave parameters during intestinal ischemia caused by total occlusion of the superior mesenteric artery. The purpose of this study was to use noninvasive biomagnetic techniques to assess functional physiological changes in intestinal slow waves in response to partial mesenteric ischemia.

Methods: We induced progressive intestinal ischemia in normal porcine subjects (n = 10) by slowly increasing the occlusion of the superior mesenteric artery at the following percentages of baseline flow: 50%, 75%, 90%, and 100% while simultaneous transabdominal magnetoenterogram (MENG) and serosal electromyogram (EMG) recordings were being obtained.

Results: A statistically significant serosal EMG amplitude decrease was observed at 100% occlusion compared with baseline, whereas no significant change was observed for MENG amplitude at any progressive occlusion levels. MENG recordings showed significant changes in the frequency and percentage of power distributed in bradyenteric and normoenteric frequency ranges at 50%, 75%, 90%, and 100% vessel occlusions. In serosal EMG recordings, a similar percent power distribution (PPD) effect was observed at 75%, 90%, and 100% occlusion levels. Serosal EMG showed a statistically significant increase in tachyenteric PPD at 90% and 100% occlusion. We observed significant increase in tachyenteric PPD only at the 100% occlusion level in MENG recordings.

Conclusions: Ischemic changes in the intestinal slow wave can be detected early and noninvasively even with partial vascular occlusion. Our results suggest that noninvasive MENG may be useful for clinical diagnosis of partial mesenteric ischemia.

Keywords: Electromyogram; Magnetoenterogram; SQUID magnetometer; Slow wave.

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Conflict of interest statement

Conflict of interest: All authors have no conflicts of interest to disclose.

Figures

Figure 1:
Figure 1:
Experimental set up to measure MENG using SQUID magnetometer and serosal EMG with serosal electrodes in a porcine model. The bundle of wires emerging from the bottom of the incision is connected to the EMG amplifier. The SQUID sensor array shown in the inset consists of 19 normal-component (z) sensors and five vector channels (marked with x) that also sample x and y magnetic field components[28].
Figure 2:
Figure 2:
A characteristic graph showing (a-b) reconstructed SOBI-MENG components with their corresponding FFTs and (c-d) CWT filtered serosal EMG signals with their corresponding FFTs at different occlusion levels ((baseline, 50%, 75%, 90% and 100%) in a normal porcine subject.
Figure 3:
Figure 3:
Mean value of the intestinal slow wave frequency at different occlusion levels (baseline, 50%, 75%, 90% and 100%) for MENG and serosal EMG recordings in porcine subjects.
Figure 4:
Figure 4:
Percent power distributed in brady-, normo- and tachyenteric frequency ranges at progressive occlusion levels (baseline, 50%, 75%, 90% and 100%) for (a) MENG recordings and (b) Serosal EMG recordings in porcine subjects.
Figure 5:
Figure 5:
Signal amplitude at progressive occlusion levels for (a) MENG recordings and (b) serosal EMG recordings. Statistically significant changes were denoted by *.
See this image and copyright information in PMC

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