A definitive diagnosis of Endometriosis cannot be made by imaging (i.e., MRI, Ultrasound, CT scan) or by clinical features (ie, symptoms or response to a medication).
Endometriosis CAN be suspected by imaging and clinical features, and these are essential parts of the diagnostic process! Unfortunately, patients are often told their imaging appears normal or that because they don’t respond to hormonal treatments, they don’t have Endometriosis. This is one of the reasons we have a horrible delay in diagnosis.
Even with a diagnostic laparoscopic surgery, just looking isn’t enough. This is why having an expert in Endometriosis doing surgery is so important. All too often, an OBGYN will do surgery, find a few areas they think are Endometriosis, and “burn” those areas.
If the area is burnt, they cannot send it to the lab, and there is no way to honestly know whether or not that area was Endometriosis.
Sometimes they will say very little, if anything at all, was found. There could be an enormous amount of Endometriosis “hiding” that they leave behind.
If they aren’t adequately trained for Endometriosis surgery, how can they possibly know what to look for or where to look for it? This is how Endometriosis is often left behind.
Endometriosis is heterogeneous, meaning it appears in various forms. Only a specialist who knows how Endometriosis can appear is capable of finding those areas, cutting them out, and then sending them to the lab.
Imaging techniques are continually improving and are great for indicating where a surgeon may need to focus during surgery, but currently cannot confirm whether or not the tissue is Endometriosis.
I want to make it clear that yes, Endometriomas (“chocolate cysts”) are often seen with imaging, but they can still be missed.
Sources:
Clement PB. The pathology of endometriosis: a survey of the many faces of a common disease
emphasizing diagnostic pitfalls and unusual and newly appreciated aspects. Adv Anat Pathol.
2007 14(4):241-60.Redwine DB. Is “microscopic” peritoneal endometriosis invisible? Fertil Steril. 1988a, 50:665-
666.From Laparoscopic Appearance of Endometriosis, Second Edition,
Martin DC, The Resurge Press, Memphis“Excision of lesions could be preferential with regard to the possibility of retrieving samples for histology. Furthermore, ablative techniques are unlikely to be suitable for advanced forms of endometriosis.” G.A.J. Dunselman, N. Vermeulen, C. Becker, C. Calhaz-Jorge, T. D’Hooghe, B. De Bie, O. Heikinheimo, A.W. Horne, L. Kiesel, A. Nap, A. Prentice, E. Saridogan, D. Soriano, W. Nelen. ESHRE guideline: Management of Women with Endometriosis. Hum. Reprod. (2014) 29 (3): 400-412.