Faculty Bibliography

Technical advances involving ultrasonographic equipment in the last years enabled the wide use of the high-resolution, 5.0 to 7.5 MHz transducers as endovaginal probes. The clear images produced are easy to interpret and, if obtained at the same time, can be used effectively to complement a routine bimanual pelvic examination. Formal teaching of the technique is imperative. This should be done by means of incorporating ultrasonography, in general, and transvaginal sonography, in particular, in formal residency training. The reasons for incorporating transvaginal sonographic examination in the standard pelvic examination done in the office or the emergency room are discussed

High-resolution transvaginal ultrasonography may recognize structures in the first- and early second-trimester fetus. In a patient with pregestational diabetes, caudal regression syndrome in the fetus was diagnosed using transvaginal ultrasonography. At 9 weeks of gestation, a shortening of the crown-rump length and a protuberance of the lower spine suggested caudal regression syndrome. By 17 weeks of gestation, the diagnosis was made with certainty. The transvaginal approach has changed the role of first-trimester ultrasound in the diabetic pregnancy. We suggest that transvaginal ultrasonography be used for purposes of accurate dating and for early detection of diabetic embryopathy, particularly in patients with poor periconceptional glycemic control

A transvaginal duplex Doppler ultrasonography system was used to measure blood flow characteristics in the ascending uterine artery before and during pregnancy. The system uses a 5 MHz Doppler transducer coupled to a 6.5 MHz imaging probe. There was a steady increase in volume flow rate in the left ascending uterine artery from a mean of 94.5 ml/min before pregnancy to a mean of 342 ml/min in late gestation (reflecting a 3.5-fold increase). With the assumption of equal flow on both uterine arteries, the fraction of the cardiac output that is distributed to these vessels was calculated to be 3.5% in early pregnancy and to reach 12% near term. The mean diameter of this vessel in the nonpregnant state was 1.6 mm, increasing to 3.7 mm toward term. The resistance to flow, expressed as the peak systolic to end-diastolic flow velocity ratio, declined from a mean of 5.3 in the nonpregnant state to a mean of 2.3 near term. These changes reflect the perpetual growth and development of the uteroplacental circulation, which provides the metabolic demands of the growing fetus throughout gestation

A total of 97 transvaginal scans were performed from 4 to 12 weeks' gestation in normal and accurately dated gestations. The sequential appearance of six structures were examined: (1) the gestational sac only was present during week 4; (2) the yolk sac appeared in week 5; (3) the fetal pole with detectable heart motion was first seen in week 6; (4) the single unpartitioned ventricle in the brain marked week 7; (5) the falx cerebri appeared during week 9; and (6) the appearance and the disappearance of the physiologic midgut herniation were seen in week 8 and week 11, respectively. Inasmuch as the time in gestation at which these structures appear characterizes the gestational age more than any measurement at this age, we propose a practical method to determine the correct gestational age in early first-trimester pregnancy

The application of high-frequency transvaginal sonography offers new opportunities in scanning for malformations during the first trimester of pregnancy. Scanning of the anterior abdominal wall and the umbilical cord insertion at this gestational age is feasible. A cross-sectional study of 61 embryos-fetuses from 7 to 12 weeks of gestation was performed to observe the physiologic midgut hernia. This herniation was detected in 64% of the cases at 8 weeks, in 100% during weeks 9 and 10, and in 25% at 11 weeks' gestation. None of the fetuses studied at 12 weeks had a midgut herniation. Vaginal sonography of the well-dated fetus at 12 weeks can confirm the final development of the anterior abdominal wall

Despite advances in diagnosis made by the introduction of serum beta-subunit of human chorionic gonadotropin determinations and transabdominal ultrasonography, ectopic gestations still present a major diagnostic challenge. The increased resolution of the transvaginally introduced high-frequency ultrasound transducer probes seems to solve this diagnostic problem. In this study 145 patients were referred for ultrasonographic workup because of a suspected ectopic gestation. In 38 patients a diagnosis could be made with classical transabdominal scanning. One hundred seventeen patients required additional transvaginal scanning with a 5.0 and a 6.5 MHz probe. In 98 patients a diagnosis was made during the first transvaginal scan; nine patients were rescanned within 3 days for the final diagnosis. In 56 patients, ectopic pregnancy was successfully ruled out by transvaginal scanning. Thirty-nine ectopic pregnancies were diagnosed. Only one false-positive identification was made. The sensitivity of diagnosing ectopic pregnancy by high-frequency transvaginal sonography was 100%; the specificity was 98.2%. The positive predictive value of this method was 98%, and the negative predictive value was 100%. The rate of the beating fetal heart was seen in the tube (23%). The high number of unruptured tubal pregnancies in this series (66%) suggests the possibility of an early diagnosis that may have therapeutic implications. The use of higher-frequency transvaginal transducer probes improves the diagnosis of the ectopic gestation

Transvaginal sonography represents a new tool for the gynecological diagnosis and decision making. The authors present theoretical and practical aspects of transvaginal sonography with special emphasis on the 6.5 MHz vaginal probe. Based on one thousand one hundred and eight examinations it is obvious that this procedure is valuable in diagnostic algorithm of ectopic pregnancy and to follow follicular growth, as well as ultrasound guided oocyte retrieval

Transvaginal sonography was compared to the traditional transabdominal sonography for diagnosing placenta previa. There was no vaginal bleeding in the 55 women studied following vaginal examination. The exact location of the internal os was diagnosed in all women by the vaginal route, and only in 36 of the 55 by abdominal scanning. Transvaginal sonography correctly diagnosed 39 out of the delivered 45 women, whereas transabdominal sonography only did so in 20 of the 45 cases. These results suggest that transvaginal sonography for the diagnosis of placenta previa is safe and superior to transabdominal sonography

Transvaginal sonography is an important tool for diagnosing ectopic pregnancy. In this report the transvaginal passage of a needle, with sonographic guidance, into a tubal gestational sac with a live fetus is demonstrated. We injected potassium chloride solution to arrest cardiac activity, terminating the ectopic pregnancy without surgical intervention. The new therapeutic use of transvaginal sonography is an important addition to the treatment of this prevalent disease