(Ultrasound Review) Radiologists at the Brigham and Women’s Hospital in Boston recently published a retrospective study aimed at increasing the accuracy of ultrasound in women with extrauterine pregnancy (EP).
Published in Journal of Ultrasound in Medicine, the study compared the echogenicity of the adnexal tubal ring seen in women with EP (study group = 39) with the echogenicity of the ipsilateral ovary. They also compared the echogenicity of the corpus luteal wall in women with intrauterine pregnancy (control group = 45) with the ovarian echogenicity.
All patients with EP included in the study had surgical confirmation of findings. Ultrasound was performed using a transvaginal approach complemented with transabdominal imaging as required.
There were a number of patients with EP (40%) who either did not demonstrate a visible mass on transvaginal ultrasound or had a solid mass but no tubal ring. The tubal ring represents the developing trophoblastic tissue. It is similar to the echogenic sac rim seen in intrauterine pregnancies that is a combination of trophoblastic and decidual tissue
In 88% of women with tubal rings containing a yolk sac or cardiac activity, the echogenicity was greater than that of the ovary. In 77% of women with empty tubal rings, the echogenicity was greater than that of the ovary.
In comparison, the wall of the corpus luteum was more echogenic than ovarian stroma in only 7% of cases. This quantitative differential has important implications for the confident, early diagnosis of EP.
The authors stress that this sign is not infallible and cite an example of an echogenic ring associated with a hemorrhagic corpus luteum in a woman with an intrauterine pregnancy too early to visualize.
The authors conclude that "In patients with adnexal masses that are contiguous or inseparable from the ovary, especially when the corpus luteum is prominent and ipsilateral to the mass, appreciation of the relative echogenicities of the mass, the normal ovary, and the corpus luteum may be helpful in the diagnosis of tubal ring and EP."
"Comparison of tubal ring and corpus luteum echogenicities"
Mary C Frates et al
Dept of Radiology, Harvard Medical School, Brigham and Women’s Hospital, 75 Francis Street, Boston, MA 02115, USA
J Ultrasound Med 2001 (January) 20:27–31
By Ultrasound Review
March 9, 2001
Click here to post your comments about this story. Please include the headline of the article in your message.
Copyright © 2001 AuntMinnie.com
