State of the art imaging for endometriosis and adenomyosis

Endometriosis is a chronic oestrogen-dependent condition characterised by the presence of endometrial-like tissue outside the uterus. Although benign, the associated chronic inflammation and fibrosis can result in substantial symptomatic burden, including chronic pelvic pain, menorrhagia, dysmenorrhoea and dyspareunia. Adenomyosis, which commonly co-exists with endometriosis, is defined by endometrial glands within the myometrium, causing chronic inflammation and fibrosis. Symptoms overlap with endometriosis, including heavy menstrual bleeding, dysmenorrhoea and chronic pelvic pain. Historically, laparoscopy with histological confirmation was considered the diagnostic gold standard for endometriosis. However, imaging now plays an essential role in noninvasive diagnosis and preoperative planning. Transvaginal ultrasound remains the first-line imaging modality in the diagnosis of endometriosis due to its accessibility, cost-effectiveness and real-time dynamic assessment. Certain forms of deep endometriosis, particularly rectal and bladder involvement, are more readily detected with ultrasound when performed by an expert operator using a structured approach that includes assessment of sliding signs and detailed evaluation of each pelvic compartment. Similarly, the Morphological Uterus Sonographic Assessment (MUSA) consensus provides a standardised ultrasound approach for the diagnosis of adenomyosis, incorporating both direct and indirect signs. Magnetic resonance imaging (MRI) offers excellent soft tissue contrast and multiplanar capability, enabling assessment of the entire pelvis and characterisation of indeterminate lesions. MRI allows the comprehensive evaluation of the parametria, ureters, nerves and bowel muscle invasive lesions beyond the reach of ultrasound. Standardised reporting systems, including the #Enzian classification, now enable a unified language between radiologists and the multidisciplinary team. Comprehensive compartment-based disease mapping is essential for accurate surgical planning and improving patient outcomes. This review illustrates the typical US and MRI appearances of endometriosis and adenomyosis, using a compartment-based approach.