A 36-year-old woman with confirmed adenomyosis and menorrhagia is referred for MRI. Which MRI finding is MOST specific for adenomyosis?

• A Uterine enlargement >12 cm on T2-weighted imaging
• B High signal T1 foci within the myometrium
• C Heterogeneous myometrial signal on T1 with gadolinium enhancement
• D Junctional zone thickness ≥12 mm on T2-weighted imaging ✓

Explanation

The most specific MRI criterion for adenomyosis is a junctional zone (JZ) thickness of ≥12 mm on T2-weighted imaging, representing thickening of the inner myometrium (stratum subvasculare) due to heterotopic endometrial glands and stroma. A JZ of 8–12 mm is indeterminate; <8 mm essentially rules out adenomyosis. High T1 foci represent haemorrhagic foci (haemosiderin deposits) and are supportive but less specific. JZ measurement is the diagnostic gold standard on MRI.

Reference: Shaw's Textbook of Gynaecology, 17th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.