Endometriosis is a common, chronic condition where tissue similar to the lining of the uterus (endometrium) grows outside the uterus. It affects approximately 10% of women during their reproductive years, equating to roughly 176 million women globally [1]. Early diagnosis significantly aids effective management, but many individuals experience long delays in diagnosis due to the complexity of recognising the condition.
Ultrasound is often the first imaging technique used when diagnosing endometriosis. However, its effectiveness depends significantly on the type and location of the endometrial tissue involved.
What Can an Ultrasound Detect?
Ultrasound imaging is particularly effective at identifying ovarian endometriomas—also known as “chocolate cysts”—which occur when endometrial tissue grows inside the ovaries. These cysts are typically visible as characteristic fluid-filled structures, easily detectable through ultrasound.
Studies have demonstrated that transvaginal ultrasound (an ultrasound performed internally via the vagina) has high accuracy, detecting ovarian endometriomas with sensitivities ranging from 83% to 100% and specificities from 89% to 100% [2].
Anatomical and Physiological Relevance
Endometriosis commonly affects specific anatomical sites, such as:
- Ovaries: Leading to endometriomas (ovarian cysts).
- Pelvic lining (peritoneum): Causing superficial lesions.
- Fallopian tubes and pelvic ligaments: Potentially leading to infertility.
- Bowel and bladder: Leading to digestive and urinary symptoms.
The endometrial tissue outside the uterus responds to hormonal changes of the menstrual cycle, bleeding and inflaming surrounding tissues, which can result in significant pain and scarring.
Symptoms Suggestive of Endometriosis
Typical symptoms of endometriosis include:
- Severe menstrual pain (dysmenorrhoea)
- Chronic pelvic pain
- Pain during or after sexual intercourse (dyspareunia)
- Heavy menstrual bleeding
- Painful bowel movements or urination, particularly during menstruation
- Difficulty conceiving (infertility)
However, symptom severity does not necessarily correlate with disease extent; some individuals with mild disease may experience severe symptoms and vice versa.
Limitations of Ultrasound in Diagnosing Endometriosis
While ultrasound effectively identifies ovarian endometriomas, it is less sensitive for detecting superficial or deeply infiltrating endometriosis (DIE), especially when located on the peritoneum (pelvic lining) or deeper tissues.
Deeply infiltrating endometriosis can involve structures such as bowel walls, bladder, ureters, or pelvic ligaments, and may require more specialised imaging techniques such as Magnetic Resonance Imaging (MRI) or laparoscopy for accurate identification.
Complications and Advanced Stages
If untreated or inadequately managed, endometriosis can lead to complications including:
- Chronic and debilitating pain
- Severe scarring and adhesions (bands of tissue binding organs together)
- Infertility or reduced fertility
- Increased risk of ovarian cyst rupture
- Rare complications such as bowel obstruction or urinary tract involvement
Advanced endometriosis significantly impacts quality of life, causing persistent physical and emotional distress.
Common Misconceptions Clarified
Misconception: Ultrasound can always detect endometriosis.
Fact: Ultrasound excels at identifying ovarian cysts (endometriomas) but often misses smaller or superficial lesions. Negative ultrasound findings do not rule out endometriosis entirely.
Misconception: Severe symptoms always mean severe disease.
Fact: Symptom severity does not reliably indicate disease stage. Mild endometriosis can produce severe symptoms, while advanced endometriosis may occasionally cause minimal symptoms.
Recommendations for Management
Individuals experiencing symptoms suggestive of endometriosis should consult a healthcare provider. Diagnosis typically begins with a detailed history, physical examination, and ultrasound imaging. Further diagnostic procedures such as MRI or laparoscopy may be recommended based on individual symptoms and clinical findings.
Early consultation and intervention are crucial for managing symptoms, preserving fertility, and improving overall quality of life.
References
- Endometriosis UK, Understanding Endometriosis. https://www.endometriosis-uk.org
- Guerriero S. et al., “Ultrasound for the diagnosis of endometriosis,” Imaging in Obstetrics and Gynecology. https://www.wiley.com
