Adenomyosis Diagnostic Approach
Adenomyosis diagnosis is primarily based on gynecologic history and imaging. Transvaginal ultrasound (TVUS) is recommended as the first-line diagnostic modality, and magnetic resonance imaging (MRI) is recommended as a second-line imaging modality in selected clinical scenarios. [1]
Clinical Evaluation
The diagnostic work-up begins with evaluation of symptoms that commonly prompt imaging, including heavy menstrual bleeding and cyclic or chronic pelvic pain. [1] A differential diagnosis should be considered during the imaging interpretation, including uterine leiomyoma, endometriosis, and other causes of abnormal uterine bleeding or pelvic pain. [1]
Transvaginal Ultrasound Findings
TVUS should be used as the first-line imaging test. [1] Imaging features should be reported using direct and indirect ultrasound findings aligned with standardized terminology (MUSA criteria). [1]
Direct ultrasound features include the following: [1]
- Myometrial cysts. [1]
- Hyperechogenic islands. [1]
- Echogenic subendometrial lines and buds. [1]
Indirect ultrasound features include the following: [1]
- Globular uterus. [1]
- Asymmetrical myometrial thickening. [1]
- Fan-shaped shadowing of the myometrium. [1]
- Translesional vascularity. [1]
- Irregular junctional zone (JZ). [1]
- Interrupted JZ. [1]
Accuracy of Ultrasound
Both MRI and ultrasound have high sensitivity and specificity for detecting adenomyosis when histology is used as the reference standard. [1] A pooled estimate from a meta-analysis cited in the recommendations reported pooled ultrasound sensitivity of 87.2% and pooled specificity of 98% for adenomyosis detection against histology benchmarks. [1]
Magnetic Resonance Imaging Findings
MRI should be considered as a second-line imaging modality after TVUS when diagnostic clarification is needed or when additional information is required. [1] MRI is recommended for assessment of disease extent, detection of concomitant gynecologic conditions, differential diagnosis support, and potential therapeutic planning. [1]
Direct MRI features cited in the recommendations include the following: [1]
- High-signal-intensity myometrial foci. [1]
- Linear striations (finger-like indentations). [1]
- Tiny myometrial and subendometrial cysts. [1]
MRI Diagnostic Reporting Nuances
JZ-based measurements on MRI should not be used as the sole diagnostic feature. [1] In particular, using JZ thickness ≥12 mm as the only MRI feature is not recommended as a stand-alone criterion. [1]
Histologic Diagnosis and Biopsy
Adenomyosis is defined histologically by endometrial glands and stroma within the myometrium. [1] Histologic confirmation can be obtained through uterine sampling techniques, including (in selected settings) hysteroscopic needle biopsy or targeted myometrial sampling approaches. [1] Uterine biopsy accuracy depends on sampling route and lesion targeting, with reported sensitivity varying substantially across studies. [1]
Diagnostic Limitations and Common Pitfalls
Agreement between TVUS and MRI for presence versus absence of adenomyosis is imperfect, and discordant imaging results can occur. [1] Several ultrasound and MRI JZ characteristics are influenced by hormonal and cycle-related factors, which can mimic or obscure adenomyosis findings. [2]
Diagnostic Bottom-Line Testing Sequence
TVUS is the first-line diagnostic modality for suspected adenomyosis. [1] MRI is recommended as a second-line diagnostic modality in selected scenarios for extent mapping, concomitant condition assessment, and diagnostic clarification. [1] Histologic confirmation through targeted sampling is reserved for situations in which tissue diagnosis is required or helpful. [1]