A new imaging tool promises to slash the nine-year endometriosis diagnosis wait by giving doctors a non-invasive way to see the disease — potentially replacing the invasive surgery currently required for a definitive diagnosis.
Diagnostic crisis
Women in the UK currently wait an average of nine years and four months for an official endometriosis diagnosis, according to figures from Endometriosis UK. That delay has crept up from eight years and ten months in 2023 and eight years in 2020. The charity describes the sustained wait as “a failure of the healthcare system to recognise and respond effectively to one of the most common chronic conditions affecting women and those assigned female at birth”. The human cost is stark: 39% of patients surveyed by Endometriosis UK said they had to visit their GP ten or more times before the condition was suspected, and 55% ended up in A&E with their symptoms — yet 46% of those were sent home without treatment. Delayed diagnosis can allow the disease to progress, leading to permanent organ damage, worsening physical and mental health, and impacting fertility decisions. For women from ethnically diverse communities, the average wait rises to eleven years.
Endometriosis happens when tissue similar to the lining of the womb grows elsewhere in the body, causing symptoms such as extremely painful and heavy periods, tiredness, and discomfort during sex or when using the toilet. Because those symptoms mimic conditions like Irritable Bowel Syndrome, patients are often misdirected for years. The current diagnostic process involves a battery of tests — vaginal examinations, ultrasounds, MRI scans — and frequently ends with a laparoscopy, an invasive surgical procedure under general anaesthetic that remains the gold standard for confirmation. Under-resourced gynaecology services, a lack of public and medical awareness, societal stigma, the normalisation of menstrual pain, and pandemic backlogs have all contributed to the bottleneck. Endometriosis UK is calling for a government commitment to cut the average diagnosis time to one year or less by 2030.
A non‑invasive alternative
The new technique, developed by the clinical radiopharmaceutical company Serac Healthcare together with the Nuffield Department of Women’s & Reproductive Health at the University of Oxford, takes a fundamentally different approach. It relies on a molecular tracer called maraciclatide that is injected into the patient. Once in the bloodstream, the tracer binds to a specific protein — αvβ3 integrin — that is produced in high quantities when new blood vessels form, a process known as angiogenesis that is a hallmark of inflammation and the growth of endometriotic lesions.
A SPECT-CT scan — a type of three-dimensional imaging that combines single-photon emission computed tomography with conventional CT — is then performed. The scan reveals where the tracer has accumulated, producing detailed images of inflamed areas or lesions anywhere in the body. The entire scan takes around twenty minutes and does not require any surgical incision. This gives clinicians a direct, non-invasive way to visualise what was previously only accessible through laparoscopy.
One of the most significant advantages is the technique’s ability to detect superficial peritoneal endometriosis, the most common form of the disease — accounting for roughly 80% of all endometriosis diagnoses — yet the hardest to spot with standard imaging such as ultrasound or MRI. Maraciclatide has received Fast Track Designation from the US Food and Drug Administration for use as a diagnostic agent for superficial peritoneal endometriosis, a status intended to speed up development and review for products addressing serious conditions with unmet medical needs.
Study findings
The results come from the DETECT (Detecting Endometriosis expressed integrins using technetium‑99m) trial, a Phase II study led by Serac Healthcare and the University of Oxford. Nineteen women completed the study; seventeen of them underwent a laparoscopy after having a SPECT‑CT scan. The imaging technique correctly identified the presence or absence of endometriosis in sixteen of the nineteen participants — an accuracy rate of 84%. Among the seventeen women whose condition was confirmed by surgery, the scan successfully imaged endometriosis in fourteen. Crucially, it picked up superficial peritoneal endometriosis that had been missed by ultrasound but later confirmed by surgery. No false positives were reported in the study.
The method also showed promise for two cases of thoracic endometriosis, a rare form of the disease in which tissue grows in the chest cavity and which is notoriously difficult to diagnose because its symptoms overlap with other respiratory conditions.
Professor Christian Becker, co‑director of the Oxford Endometriosis CaRe Centre and co‑lead of the study, said: “Novel, non‑invasive diagnostic tests for endometriosis are a global research priority. The diagnostic challenge of endometriosis, which presents with varied and non‑specific symptoms, is exacerbated by an absence of clinically validated biomarkers and the limitations of currently available imaging techniques.” If the findings are replicated in larger studies, he added, maraciclatide could become “an extremely valuable tool” that could “reduce diagnostic delays” and help develop new treatments.
Dr Tatjana Gibbons, of the Nuffield Department of Women’s and Reproductive Health at the University of Oxford, described the results, published in The Lancet Obstetrics, Gynaecology & Women’s Health, as “exciting”. She said they show maraciclatide “offers a highly promising diagnostic and monitoring tool, particularly for superficial peritoneal endometriosis, which is the most common and yet the hardest type of endometriosis to identify”. She added: “We are hugely grateful to the patients who have participated in the DETECT study without whom investigating this diagnostic approach would not have been possible.”
Professor Krina Zondervan, co‑director of the Oxford Endometriosis CaRe Centre and head of the Nuffield Department of Women’s and Reproductive Health, said: “If these results are confirmed in larger phase three studies, imaging with maraciclatide could transform clinical research and practice and potentially empower the development of treatments for women across the globe.” The economic burden of endometriosis in the UK alone is estimated at £8.2 billion a year in treatment, lost work and healthcare costs, while the disease has a significant genetic basis, with research suggesting different subtypes may need different treatments. Other non‑invasive diagnostic approaches are also being explored, including microRNA‑based tests and protein‑based blood tests, but none have yet reached the point of clinical adoption. For now, maraciclatide offers the clearest prospect yet of turning a nine‑year wait into a single outpatient appointment.