Optimal Timing for Adenomyosis Diagnosis on Scan
Adenomyosis should be evaluated during the early proliferative phase (days 4-6) of the menstrual cycle when the endometrium is thinnest, allowing for optimal visualization of myometrial features and junctional zone abnormalities. 1
Rationale for Early Proliferative Phase Imaging
The endometrium is at its thinnest during days 4-6 of the cycle, which minimizes interference with visualization of the underlying myometrium and junctional zone—the key anatomical areas where adenomyosis manifests 1
Endometrial thickness varies significantly throughout the menstrual cycle in premenopausal women, and imaging during other phases may obscure adenomyotic features or create diagnostic confusion 1
Transvaginal ultrasound combined with transabdominal approach should be used to fully assess pelvic structures and ensure the endometrium and myometrium are adequately visualized 1
Diagnostic Performance Considerations
Transvaginal ultrasound using MUSA criteria demonstrates pooled sensitivity of 82.5% and specificity of 84.6% for adenomyosis diagnosis, making it the first-line imaging modality 2, 1
Detection of adenomyosis may be limited if coexisting uterine pathology such as leiomyomas is present, with sensitivity dropping from 97.8% to 33.3% when fibroids are present 1
MRI should be considered when ultrasound is inconclusive or adenomyosis obscures endometrial visualization, with MRI demonstrating 78-88% sensitivity and 67-93% specificity 2, 1
Key Imaging Features to Assess
Junctional zone thickening and altered appearance are characteristic findings, more commonly seen in older reproductive age women (67.1% in >35 years vs. 39.3% in 18-35 years) 3, 2
Focal versus diffuse adenomyosis patterns should be characterized, as diffuse disease is more prevalent in advanced reproductive age (76.7% vs. 39.3% in younger women) 3
Myometrial cysts, asymmetric myometrial thickening, and subendometrial echogenic linear striations are additional ultrasound markers to evaluate 4, 5, 6
Common Pitfalls to Avoid
Do not accept imaging performed during the secretory phase or menstruation as optimal for adenomyosis diagnosis, as endometrial thickening during these phases obscures myometrial detail 1
Approximately 16% of symptomatic patients may not demonstrate direct ultrasound signs despite clinical adenomyosis, requiring integration of clinical context with imaging findings 2
Standard pelvic ultrasound protocols do not routinely include the detailed assessment needed to identify adenomyosis features, so ensure the sonographer is specifically evaluating for adenomyosis using MUSA criteria 2