Which of the following MRI features is MOST specific for adenomyosis (not fibroid)?
- A Junctional zone thickness >12 mm on T2-weighted MRI ✓
- B Well-defined low-signal-intensity mass on T2-weighted imaging
- C Endometrial cavity displacement
- D Calcifications within the uterine wall
Correct answer: A. Junctional zone thickness >12 mm on T2-weighted MRI
Explanation
On T2-weighted MRI, adenomyosis appears as diffuse or focal thickening and loss of clarity of the junctional zone (JZ) — the inner myometrium. A JZ thickness >12 mm (or JZ maximum minus minimum >5 mm) is the most specific MRI criterion for adenomyosis. Fibroids appear as well-defined, discrete low-T2-signal nodules that displace the endometrial cavity. Diffuse JZ thickening without a discrete mass favours adenomyosis.
Reference: Shaw's Textbook of Gynaecology, 17th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.