Does the 10-MHz transvaginal transducer improve the diagnostic certainty that an intrauterine fluid collection is a true gestational sac?
OBJECTIVE
We studied whether a 10-MHz transvaginal transducer improves the diagnostic certainty that a small intrauterine fluid collection is a true gestational sac.


METHODS
Over a 6-week period, women who presented with a positive pregnancy test and a fluid collection (devoid of any characteristics such as yolk sac or fetal pole) in the uterus seen with a standard 6-7-MHz transvaginal transducer were entered in the study. The patients were immediately rescanned with a 10-MHz transvaginal probe, and characteristics of the fluid collection using this probe were noted. Specifically, the visualization of a yolk sac or the intradecidual or double decidual sign was considered an objective improvement in the certainty that the fluid collection was a gestational sac.


RESULTS
Twelve patients presented with a positive pregnancy test and a fluid collection in the uterus seen with a 6-7-MHz probe. Eight of these fluid collections were smaller than 1 cm in mean diameter, and all 8 of these patients had an objective improvement in the diagnosis of an intrauterine pregnancy using the 10-MHz probe. The other 4 patients had fluid collection 1-2 cm in mean diameter seen at 6-7 MHz. The 10-MHz probe improved the diagnostic confidence in 2 of these 4 patients.


CONCLUSIONS
In patients with early pregnancies who have questionable gestational sacs on sonography with standard 6-7-MHz transducers, the 10-MHz probe improves the diagnostic confidence of the presence of an intrauterine gestational sac.
Benacerraf
B R
BR
Department of Obstetrics and Gynecology, Massachusetts General Hospital, 32 Fruit Street, Boston, Massachusetts 02114, USA.
Shipp
T D
TD
Bromley
B
B
D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D011247:Pregnancy; D011258:Pregnancy Tests; D011271:Pregnancy, Ectopic / Q000000981:diagnostic imaging; D016216:Ultrasonography, Prenatal / Q000295:instrumentation*; D015017:Yolk Sac / Q000000981:diagnostic imaging*