Abstract Title: Defining the Role of the Gastrointestinal Myoelectrical Activity (GIMA) Biomarker in the Diagnosis of Endometriosis
Presented by Mark Noar, MD, MPH on behalf of study authors P Tanos, F Donders, A Massaro, S Philippe, S Kampala
Thank you very much. My name is Mark Noar, and I am here at the invitation of the authors because they were unable to make it, so they’ve asked me to please standin to be able to do this presentation. We will talk about defining the role of gastrointestinal myoelectrical activity, or GIMA, as a biomarker in the diagnosis of endometriosis.
The authors have no disclosures. With regard to need to disclose, who are the authors? This is a tertiary center in Endometriosis at the CHU Bruggman in Brussels. It’s a multidisciplinary team. They meet twice weekly to review all of their patients. In terms of their case numbers, they do at least 1200 cases for consultation for endometriosis a year with 350 new cases diagnosed and more than 60 DIE surgeries in a year’s time.
Over the past few years, they’ve been looking at diagnostic ability, and in particular using MRI, and they’ve noticed up in from 2021 to 2024, there’s been a dramatic improvement with use of MRI. In particular, we see sensitivities and specificities increasing to 67% and 100%. With a diagnostic accuracy of 88%.
Yet, despite these improvements, there are still cases where MRI will miss cases as well as transvaginal ultrasound. Here are two examples. One in the ureteral vascular space, a vesicular space in the other, a deep endometriosis nodule in the uterosacral ligament. So what can we do? Well, we began talking to them about the ENDOSURE test.
They began to look at this, which is a non-invasive 30-minute test to diagnose endometriosis, and they felt perhaps this might be an inviting technology. The basis for the test is that the interstitial cells of cajal control the normal contraction of the gut, which is 10 to 15 cycles per minute.
However, endometriosis tissue produces high levels of PG-E2 and PG-Falpha, and this causes both spasm and peristalsis in the small gut. This has been published since 1998, and so we detect that by placing electrodes on the abdomen and when that happens, we end up with these very abnormal patterns, as you can see here in frequencies between 20 to 60 cycles per minute.
And here are two of the publications in which this is detailed. So with this information. The question for them became, “Hey, this is non-invasive. This is a good alternative for the patient experience. You get a numerical value of the activity of the disease. Will this help predict severity as well as response?
Will it correlate with inflammation, in particular with can we detect superficial as opposed to just DIE? And then finally, since no expert training is needed, will this be easy for us to use?” Now, they were really very intrigued by this first case that they did. Which is a 29-year-old woman who had pelvic pain between a level of five and six.
She was on constant medication, as you can see here, and her transvaginal ultrasound was normal. And they use #Enzian for all of the reviews. However, her end value was 0.89. Now 0.5 and above is positive for disease and so they took her to surgery and as you can see here, there is not only superficial disease.
And so the surgical staging finally using #Enzian along with the surgical staging, was actually a P two B one. It did a deep nodule resection. It extended about greater than 15 millimeters, although it appeared to be much less deep than that, and she ended up with peritonectomy, as you can see there.
So they designed a study and so the methodology is this. It’s a prospective cohort study looking at women with chronic pelvic pain as a presentation. This was done between December of 2024 and September of 2025. The study continues on, but this is the 91 patients in the study.
They interviewed a total of 240 who went through the normal 30-minute consultation and examination, and then they referred 56 of them for TVUS and 38 of them went for MRI of the pelvis. All 91 underwent the GIMA test, which is ENDOSURE. 15 of those patients in the case where there was discrepancy between the results went to surgery as the final arbiter of what was found.
Again, as I mentioned, they used the #Enzian whenever they’re evaluating transvaginal ultrasound, MRI or even surgical results. These are the results. So with those 91 patients, the average age was 30.9, BMI of 24.16. Then most of them were null para patients. And you see some associated diseases there. 31 of the 91 patients were on no suppressive therapy whatsoever, and the others were on various treatments such as dienogest, combined oral contraceptives or GNRH agents. Now if we take a look at the results compared to the standard of care, if we compare the GIMA marker to MRI or the GIMA to ultrasound, you’ll see the sensitivity was 96.4 and 93.8 respectively, with the specificity of 25 and 30.8. Now, when you use surgery to take care of your discrepancies. What ends up happening is, is that you end up with a hundred percent sensitivity of the GIMA biomarker compared to MRI and a hundred percent sensitivity compared to transvaginal ultrasound, elevating the specificities to 50 and 66% respectively.
Comparing all of the technologies together what we have is, there’s really no significant difference between them. They’re all very good at diagnosing endometriosis and so they felt the conclusion was that the GIMA performs just as comparably as others. Now, satisfaction wise, the patients are very, very happy with the ENDOSURE test, and the only complaint is they don’t have enough interaction with the doctor because it’s done with the technician.
In conclusion. Very high sensitivity, a hundred percent. So you’re unlikely to meet miss DIE or other endometriosis. However, it can potentially generate false positives. And there’s moderate specificity owing to the fact that there were very few normal patients in the study. It’s got excellent negative predictive value of a hundred percent.
So we know that the GIMA biomarkers reliably can also exclude disease. The practical implications are this is a TIER-1 diagnostic test. It’s the first time that we have this. In the field, it can serve as a non-invasive accessible first line test to find out who would require further imaging or surgical evaluation.
And it’s probably very good in the primary or outpatient settings where you don’t have expert MRI or transvaginal ultrasound expertise. We do have to be careful though, because the lower specificity means that ENDOSURE could not replace imaging, but act really as a triage tool. Also, larger perspective validation studies with more normal patients will be necessary to define this as an actual diagnostic test that could lead the pack.
And the test is really not specific to anatomic location or staging, but what it does give you is a metabolic activity level that changes in response to treatment in the patient’s response to their treatment.
And I thank you for your attention.