Diagnostic Ultrasound - Abdomen and Pelvis

Adenomyosis
TERMINOLOGY
Synonyms
• Uterine endometriosis
• Endometriosis interna
Definitions
• Heterotopic endometrial tissue within myometrium with
adjacent smooth muscle hyperplasia
IMAGING
General Features
• Best diagnostic clue
○ Uterine enlargement with poor definition of
endometrial-myometrial interface
○ Myometrial cysts in up to 50%
– Usually subendometrial
• Location
○ Diffuse or asymmetric myometrial involvement
– Superficial type: Involving < 1/3 of myometrial
thickness
– Deep type: Invasion > 1/3 of myometrial thickness
– When asymmetric, posterior > anterior myometrium
○ May be more focal and mass-like, resulting in
adenomyoma
– Often near endomyometrial junction
• Size
○ Variable
• Morphology
○ If confluent/diffuse, globular enlarged uterus with
smooth external contour
○ If focal, commonly elliptical myometrial mass
Ultrasonographic Findings
• Globular uterine enlargement
• Heterogeneous myometrial echotexture
○ Hypoechoic smooth muscle hyperplasia
○ Echogenic linear striations due to endometrial extension
into myometrium
• Loss of endomyometrial interface due to thickening of
junctional zone
• Cysts within myometrium
○ Anechoic, usually subendometrial
○ Highly specific for diagnosis
○ Distinguish from uterine veins, which are peripheral,
have color flow
• Disordered or uncircumscribed myometrial vascular pattern
on color Doppler
• If mass-like, difficult to differentiate from leiomyoma but
less distinct
○ Often emanates from endomyometrial junction
○ Penetrating vessels without mass effect on color
Doppler
○ Not calcified
• Tender with probe pressure
MR Findings
• Thickened junctional zone (> 12 mm) on T2WI, diffuse or
focal
• Focal areas of T2 increased signal due to dilated
endometrial glands
• May have focal areas of T1 increased signal due to
hemorrhage
• If mass-like, difficult to differentiate from leiomyoma
○ Often near junctional zone
○ T2 hypointense due to smooth muscle hyperplasia
○ Similar enhancement patterns as leiomyoma
Fluoroscopic Findings
• Hysterosalpingography (HSG)
○ Small diverticula extending from endometrial cavity
Saline-Infused Hysterosonography
• Saline and bubbles may fill linear tracks in myometrium,
producing "myometrial cracks"
Imaging Recommendations
• Best imaging tool
○ US best initial study for patients with pelvic symptoms
– Transvaginal ultrasound best to evaluate
endomyometrial interface
○ MR for equivocal, difficult, or nondiagnostic cases
– T2WI best to evaluate junctional zone
– Less limited by size of uterus and patient
– More comprehensive evaluation of fibroid burden
– Not limited by shadowing
• Protocol advice
○ Cine clips with slow sweep are helpful for subtle findings
such as streaky shadowing and small myometrial cysts
○ Evaluate for uterine tenderness
DIFFERENTIAL DIAGNOSIS
Leiomyoma
• US: Well-defined mass in submucosal, subserosal, or mural
location
○ May be difficult to distinguish from adenomyoma
• Often multiple, with lobular external uterine contour
• Can be calcified with peripheral vascularity
• MR: Low T1/T2 signal with nonthickened junctional zone
Diffuse Myometrial Hypertrophy
• Endometrial-myometrial borders maintained
• Junctional zone remains well defined
• Heterogeneous myometrium without other findings
Endometrial Cancer
• Irregularly thickened heterogeneous endometrium
• Possible invasion into myometrium with loss of
endomyometrial interface
Metastasis to Uterine Corpus
• Rare, most commonly breast, gastric cancers and
lymphoma
• Lymphoma rarely primary
○ Hypoechoic infiltration, preserves contour with less mass
effect on endomyometrial interface
Endometrial Hyperplasia
• Thickened endometrium, may have cystic appearance
• Typically preserved endomyometrial interface
Diagnoses: Female Pelvis
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