Ultrasound Findings on Adenomyosis
Transvaginal ultrasound (TVUS) demonstrates adenomyosis with a pooled sensitivity of 82.5% and specificity of 84.6%, making it the first-line imaging modality for diagnosis 1.
Key Diagnostic Features
The most accurate sonographic findings for adenomyosis include:
High-Specificity Features
Subendometrial echogenic linear striations - This is the most specific finding (95.5% specificity) with the highest positive predictive value (80%) 2. These appear as hyperechoic lines extending from the endometrium into the myometrium.
Myometrial cysts - Small cystic spaces within the myometrium, present in approximately 82% of adenomyosis cases 3. These represent ectopic endometrial glands.
Globular uterus - A regularly enlarged, rounded uterine configuration with 78.1% specificity 4. This was present in 95% of confirmed adenomyosis cases 3.
High-Sensitivity Features
Heterogeneous myometrial echotexture - The most common finding (86% sensitivity), though it has poor specificity as it can occur with fibroids 4, 2. All patients with adenomyosis in one study demonstrated this mottled, inhomogeneous appearance 3.
Asymmetrical myometrial wall thickness - Particularly between anterior and posterior walls, with high diagnostic accuracy when combined with other features 2, 5.
Indistinct endometrial-myometrial junction - Present in 82% of adenomyosis cases, representing disruption of the normal junctional zone 3.
Diagnostic Approach
When at least 2 of the above ultrasound features are present, diagnostic accuracy reaches 90% (sensitivity 92%, specificity 83%) 5.
Technical Considerations
Combine transabdominal and transvaginal approaches for complete uterine assessment 1. The transabdominal view provides anatomic overview for enlarged uteri, while TVUS offers superior spatial and contrast resolution for detecting myometrial changes.
Important Caveats
Diagnostic accuracy drops significantly in specific scenarios:
- Coexisting leiomyomas: Sensitivity falls from 97.8% to only 33.3% when fibroids are present 1. Multiple small fibroids can mimic the heterogeneous appearance of adenomyosis.
- Previous endometrial ablation: Accuracy decreases to 50% due to altered junctional zone appearance 5.
- Active hormonal therapy: Accuracy drops to 60% as treatment modifies ultrasound features 5.
Advanced Ultrasound Techniques
3D Ultrasound
For junctional zone assessment, measure both minimum (JZmin) and maximum (JZmax) thickness. JZmax ≥8 mm has 83% specificity for adenomyosis 5. However, 3D ultrasound does not significantly improve overall accuracy compared to 2D TVUS 4.
Doppler Ultrasound
While Doppler can be performed, there are no definitive studies demonstrating it can differentiate adenomyosis from leiomyomas 1. Translesional vascularity may be more common in external adenomyosis phenotypes 6.
Phenotype Recognition
Recent evidence identifies two distinct patterns:
- Internal adenomyosis (70%): Diffuse involvement, more ultrasound features, globular morphology, frequently coexists with leiomyomas, affects older multiparous women 6.
- External adenomyosis (30%): More focal, associated with deep endometriosis, translesional vascularity, affects younger nulliparous women 6.
When Ultrasound is Insufficient
If TVUS findings are indeterminate or the uterus is incompletely visualized, MRI should be considered with sensitivity 78% and specificity 93% 1. MRI excels at displaying the endometrium even when obscured by adenomyosis or fibroids on ultrasound.