Diagnosis of an interstitial pregnancy with 4-dimensional volume contrast imaging

The purpose of this study was to investigate the use of a new ultrasound technique, termed 4-dimensional volume contrast imaging in coronal-plane to facilitate the early detection of interstitial pregnancy.

A case of interstitial pregnancy was diagnosed accurately at 6 weeks of gestation with 4-dimensional transvaginal volume contrast imaging in coronal plane technology. A scan of the uterus revealed that the eccentric gestational sac was located in the right uterotubal junctional area, lying 1 cm outside the most upper lateral edge of the uterine cavity with thick endometrial echoes.

After the appropriate counseling, the patient was treated with an ultrasonographically guided intracardiac injection of 2.5 mEq of potassium chloride followed by aspiration of the gestational sac. A transvaginal scan immediately after the procedure demonstrated a collapsed empty gestational sac. Three months after the conservative treatment, the serum beta-human chorionic gonadotropin level fell to 1.17 mIU/mL, and normal echotexture of the uterus was noted.

Four-dimensional volume contrast imaging in coronal-plane technology provides scan planes that are not accessible by conventional 2-dimensional scanning, with enhanced tissue contrast resolution in region of interest. This new ultrasound technique has the potential to provide more accurate, inexpensive and less variable virtual reality image-guided interventional options through more realistic interaction with the virtualized in utero condition, particularly when 2-dimensional transvaginal scan fails to differentiate between interstitial, angular, and cornual pregnancies.