Many patients ask how endometriosis is diagnosed today and whether surgery is still required. Modern diagnosis increasingly combines clinical assessment with high-quality pelvic imaging such as ultrasound and MRI, allowing disease to be mapped before surgical treatment is considered.

For many years, patients were told that the only way to diagnose endometriosis was surgery. That is no longer accurate.

Our understanding of endometriosis has evolved significantly. We now recognise it not simply as a pain condition, but as a complex structural and inflammatory disease with predictable anatomical patterns. At the same time, the tools used to detect and map that disease have improved. Modern guidelines reflect this shift. Endometriosis is not diagnosed by symptoms alone. It is not diagnosed by imaging alone. And it should not be diagnosed by surgery performed in isolation. Current international guidance recommends a structured pathway that integrates clinical assessment with high-quality pelvic imaging before operative intervention is considered [1,2].

Good medicine starts with diagnostic clarity. Before any intervention – particularly irreversible ones – disease should be defined with the highest accuracy reasonably achievable. That is not aspirational. It reflects the minimum standard outlined in contemporary guidelines [1,2].

Diagnosis Begins With Suspicion – But Does Not End There

Severe period pain, deep pain with intercourse, chronic pelvic discomfort, infertility, or cyclical bowel and bladder symptoms should raise suspicion for endometriosis [1,2]. These symptoms are common in clinical practice and should not be dismissed as “normal variation.”

However, symptoms alone do not tell us where disease is located – or how much of it is present [3]. Pain severity does not reliably correlate with anatomical burden. Some patients with extensive deep infiltrating endometriosis report modest symptoms, while others with limited visible disease experience severe pain. Physical examination may also be normal, particularly in early or superficially distributed disease.

Endometriosis is also associated with a modest but measurable increase in the risk of certain ovarian cancer subtypes, particularly endometrioid and clear cell carcinoma. Large population analyses suggest the relative risk may be increased up to fourfold for specific histologic types, although the absolute lifetime risk remains low [4]. This association reinforces the importance of accurate diagnosis and appropriate longitudinal care – not alarm, but clarity.

For that reason, suspicion should prompt structured investigation. It should lead to anatomical definition – not immediate operative escalation.

Imaging Is Foundational to Modern Diagnosis

So how is endometriosis diagnosed today?

Imaging technology has advanced considerably. Resolution is higher, protocols are more refined, and our understanding of pelvic disease distribution has improved [5,6]. While no diagnostic tool is perfect, contemporary protocol-driven imaging is now recognised as a central component of responsible diagnosis [1,2].

High-quality imaging can:

Map pelvic compartment involvement
Identify deep infiltrating endometriosis
Assess bowel, ureteric and bladder extension
Inform surgical complexity before incision

International guidelines support imaging as part of the diagnostic work-up and do not require diagnostic laparoscopy before initiating treatment [1,2].

Surgery remains important – but it is invasive and irreversible. As with any higher-risk intervention, it should generally follow appropriate lower-risk diagnostic evaluation and proportionate management [1,2].

Imaging is not a delay in care. It is part of safe care.

What Modern Imaging Can Actually Show – and Why Quality Matters

When performed using a dedicated endometriosis protocol and interpreted by experienced clinicians, modern pelvic imaging can provide detailed anatomical mapping that meaningfully informs management [1,2,5,6].

It can define anterior, middle, and posterior compartment involvement. It can detect deep infiltrating disease within the uterosacral ligaments, rectovaginal septum, or torus uterinus. It can assess bowel involvement and, in appropriate cases, determine depth of invasion – a detail that directly influences surgical technique [5]. It can identify ureteric or bladder extension before surgery begins, reducing unexpected intraoperative findings [5,6].

When performed well, imaging transforms surgery from exploratory to planned [1,2,5,6].

However, imaging is not a uniform product.

Unlike blood tests, where methodology is tightly standardised, imaging fidelity varies considerably between providers [5,7]. Two scans labelled “pelvic MRI” or “pelvic ultrasound” can differ substantially in what they actually demonstrate.

Image quality depends on:

Hardware capability
Software optimisation
Protocol design (routine pelvic study vs dedicated endometriosis protocol)
Time allocated for acquisition
Technologist expertise
Reporting radiologist experience

Imaging for suspected endometriosis should not be performed using a generic pelvic protocol. Dedicated endometriosis protocols include targeted sequence selection, systematic compartmental assessment, and focused evaluation of structures commonly involved in deep infiltrating disease [5–7]. Diagnostic accuracy improves when imaging is protocol-driven and performed by experienced operators, whereas routine imaging may underperform in detecting deep or compartmental disease [5–6].

Equally important is how findings are reported. Structured reporting systems such as the ENZIAN classification provide a standardised method for describing the location and extent of deep infiltrating endometriosis across pelvic compartments [8]. The #Enzian system allows imaging findings to be communicated in a way that aligns with surgical anatomy and operative planning, improving multidisciplinary coordination and reducing ambiguity.

Without protocol-driven acquisition and structured reporting, disease may be under-characterised – even when imaging has technically been performed.

A poor-quality scan may show nothing clearly – but it also does not show its own limitations. To a patient or referring doctor, it may simply appear “normal.”

Superficial implants and small lesions remain difficult to evaluate radiologically, even in experienced hands [3]. A normal scan therefore does not exclude endometriosis – particularly superficial peritoneal disease [1,3].

Guideline-supported diagnosis does not simply mean “having a scan.” It means having the appropriate scan, performed using specialised protocols and reported within a structured, anatomically aligned framework [1,2,8].

High-quality imaging is about diagnostic fidelity – and fidelity supports safer surgical planning.

What If Imaging Is Negative?

A normal scan can be reassuring – but it is important to understand what that reassurance does and does not mean.

Imaging is effective at identifying deep structural disease and reducing uncertainty around anatomically significant involvement [5,6]. What it does less reliably is detect superficial peritoneal implants [3].

A negative scan does not mean “no endometriosis.” It means deep structural disease has not been identified.

If symptoms remain significant and imaging is negative, management should remain measured. A trial of medical therapy is reasonable, and referral for specialist review may be appropriate. Current guidelines do not require surgical confirmation before initiating treatment, and surgery should not be the automatic next step in the absence of imaging-defined disease [1,2].

Imaging does not replace clinical judgement. It refines it.

Why Surgery Without Imaging Is Problematic

Surgery can be transformative in endometriosis care. But operating without prior anatomical mapping introduces avoidable uncertainty.

Deep infiltrating disease may involve bowel, ureters, bladder, uterosacral ligaments or pelvic sidewall structures. Dedicated imaging can identify and map these compartments preoperatively [5,6]. Guidelines recognise imaging as part of appropriate diagnostic work-up before surgical intervention [1,2].

Without mapping, disease extent may be underestimated. Bowel involvement may not be fully appreciated. Ureteric encasement may go unrecognised. Disease may be incompletely excised. These reflect the structural complexity described in both imaging and surgical literature [3,5,6].

Imaging also supports appropriate counselling. Patients deserve clarity regarding likely surgical extent and multidisciplinary involvement [1,2].

Discovering significant bowel disease only once surgery has begun is reactive management.

Modern practice favours anatomical clarity before incision.

The Responsible Diagnostic Pathway

A responsible diagnostic pathway now prioritises clarity before intervention. Clinical assessment raises suspicion, specialised imaging defines anatomy, and treatment decisions follow from what is actually present.

Surgery remains an important tool in endometriosis care — but modern medicine increasingly aims to understand disease before operating on it.

Imaging is not a delay in care. It is the process by which care becomes precise.

References

1. European Society of Human Reproduction and Embryology (ESHRE). Endometriosis guideline. 2022.

2. Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG). Endometriosis clinical practice guideline (Living Guideline). 2023.

3. Woodward PJ, Sohaey R, Mezzetti TP Jr. Endometriosis: radiologic-pathologic correlation. Radiographics. 2001;21(1):193–216.

4. Pearce CL, Templeman C, Rossing MA, et al. Association between endometriosis and risk of histological subtypes of ovarian cancer: a pooled analysis. Lancet Oncol. 2012;13(4):385–394.

5. Tong A, Cope AG, Waters TL, McDonald JS, VanBuren WM. Best practices: ultrasound versus MRI in the assessment of pelvic endometriosis. AJR Am J Roentgenol. 2024;223:e2431085.

6. Harth S, Roller FC, Zeppernick F, Meinhold-Heerlein I, Krombach GA. Deep infiltrating endometriosis: diagnostic accuracy of preoperative magnetic resonance imaging with respect to morphological criteria. Diagnostics (Basel). 2023;13(10):1794.

7. Băușić A, Coroleucă C, Coroleucă C, Comandașu D, Matasariu R, Manu A, et al. Transvaginal ultrasound vs magnetic resonance imaging (MRI) value in endometriosis diagnosis. Diagnostics (Basel). 2022;12(7):1767.

8. Keckstein J, Saridogan E, Ulrich UA, Sillem M, Oppelt P, Schweppe KW, et al. The #Enzian classification: a comprehensive non-invasive and surgical description system for endometriosis. Acta Obstet Gynecol Scand. 2021;100(7):1165–1175.

Author: Dr Kirralee Sherif (PhD)