Uterine anatomy on MRI
Endometrium – High
Junctional zone (inner myometrium) – Low
Outer myometrium – Intermediate (relatively high to junctional zone)
Cervix stroma – Low
- What is junctional zone?
- Junctional zone (JZ) is a hormone dependent zone located between the endometrium and myometrium passing through cyclical changes in its thickness
- Junctional zone (JZ) is a hormone dependent zone located between the endometrium and myometrium passing through cyclical changes in its thickness
- Why the junctional zone shows low signal intensity on T2WI
- dense myocytes
- large size nucleus
- looser extracellular matrix
- lower water content
- Does the junctional zone enhances with contrast injection ?
- On T1WI CE – no ehnacement
- Dynamic contrast enhancement (DCE) : subendometrial enhancement (on early phase)
Left : T2WI
Right : DCE, subendometrial enhancement is seen on the image. the patient is diagnosed with endometrial cancer (FIGO 1A)
Uterine anatomy on TVUS (transvaginal ultrasound)
- Menstrual phase
- Endometrium : Thin (less than 4mm), absent zonal appearance
- Endometrial lining is seen as high echoic line on TVUS
- Proliferative phase
- Late proliferative phase : Trilaminar appearance of endometrium
- Innermost high echoic layer – mid low echoic layer = functional layer (influenced by hormone)
- Outermost high echoic layer = basal layer (not influenced by hormonal change)
- Secretary phase
- Endometrium : Most thickened on secretary phase (7~14mm) showing homogenously thickened hyperechoic endometrium
- Myometrium : Increased signal intensity on T2WI
- Menopause : Less than 5mm
- Menopause with HRT : Less than 10mm
- Oral contraceptive
- Junctional zone, endometirum : thin
- Myometrium : increased signal
See other posting about Genitourinary imaging
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