Which of the following is the MOST sensitive investigation to diagnose a cornual (interstitial) ectopic pregnancy?

• A Transvaginal ultrasound showing gestational sac > 1 cm from uterine cavity
• B Serum β-hCG > 1000 IU/L with empty uterine cavity on TVS
• C Laparoscopy revealing asymmetric uterine enlargement
• D MRI showing myometrial mantle < 5 mm around the gestational sac ✓

Explanation

Interstitial (cornual) ectopic pregnancy is specifically diagnosed on ultrasound or MRI by the characteristic finding of a gestational sac located eccentrically in the uterus, > 1 cm from the endometrial cavity, surrounded by a myometrial mantle of < 5 mm. MRI provides superior tissue characterisation and is used when ultrasound is equivocal. The 'interstitial line sign' (echogenic line extending from endometrial cavity to the gestational sac) is specific on ultrasound.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.