Faculty Bibliography

The introduction of transvaginal sonography has enabled the use of this scanning method for guided puncture procedures. A total of 102 puncture procedures are described: 63 fetal reductions, eight punctures of ectopic pregnancies, 19 drainages of pelvic contents, seven punctures of ovarian cysts, four diagnostic culdocenteses and one injection of a cervical pregnancy.Every procedure is discussed in detail. There was only one procedure-related complication. The advantages of the ultrasound-guided vaginal puncture procedure are its performance under real-time imaging, a low complication rate, a better pregnancy outcome when considering the reduction of multifetal gestations, and, most importantly, the fact that abdominal surgery can be avoided in several cases

A 6.5 MHz transvaginal sector scanner was used to describe the fetal central nervous system anatomy from 6 to 14 weeks. One hundred thirty-three pregnant patients were scanned after the crown-rump measurements were found to be within a range of less than or equal to 4 days from menstrual age. The number of possible ultrasonographic sections ('slices'), as well as the number of successful views in the axial, coronal, and sagittal sections, was tabulated. A detailed list of central nervous system structures that are seen at each gestational age is presented. The results showed that a significant number of brain structures could be imaged. The number and the clarity of the structures and the number of successful views in the three scanning planes increased with gestational age. We concluded that transvaginal scanning for central nervous system maldevelopment can be started in the late first and early second trimesters

High-frequency transvaginal probes were used at 20-40 weeks' gestation to develop a systematic examination of the fetal brain. Modeling the procedure after the standard neonatal neurosonographic examination, we attempted to obtain three coronal sections (anterior, midline, posterior) and two sagittal sections (midsagittal, right or left parasagittal). In 70 normal patients, all planes were imaged with a similar frequency (74-76%) except for the posterior coronal plane, which was imaged 59% of the time. Among the first 35 cases, 17% had a complete study, compared with 71% of the second 35 cases. Transvaginal sonography established or changed the diagnosis in five of the 13 cases with central nervous system or other abnormalities. We recommend that a complete fetal neurosonographic examination include transvaginal sonography to complement and enhance the transabdominal examination, especially for cases in which a fetal abnormality is suspected

Republished from Obstetrics & gynecology. 1990; 75(3 Pt 2):486-489

Transvaginal ultrasonography was used to evaluate antepartum bleeding in a group of 76 patients at varying gestational ages with suspected placenta previa. The clinical outcome of 16 patients with persistent placenta previa was documented. Nine of the 16 patients had placental lacunar blood flow. Two of the nine patients were lost to follow-up. At cesarean section the seven patients with lacunar flow had a higher incidence of blood loss, transfusion requirements, abnormally implanted placenta, and cesarean hysterectomy than the six patients in whom no lacunar flow patterns were seen (p = 0.002). The finding of these flow patterns with abnormally located placentas suggests the anticipation of significant blood loss and probable extension of operative procedures to stop the blood loss

Perfusion characteristics of the female pelvic vessels were studied by a high-frequency transvaginal image-directed Doppler system. A 5-MHz Doppler transducer was coupled to a 6.5-MHz probe especially designed for intravaginal use. Distinct patterns of flow velocity waveforms were obtained from the ascending branch of the uterine artery, before and during pregnancy. A gradual increase in diastolic flow throughout gestation was observed, consistent with a decrease in vessel resistance. Flow velocity profiles in the ovarian artery were sampled from the infundibulo-pelvic ligament. Only limited diastolic flow could be detected in either ovary during the follicular phase of the cycle. In the luteal phase there was a marked increase in this flow but only in the ovary containing the corpus luteum. In early pregnancy the high diastolic flow was maintained or even increased, consistent with a low arterial resistance. High image resolution and a higher frequency Doppler transducer increase the usefulness of this technique in the hemodynamic evaluation of the female pelvic vessels

The accuracy of the diagnosis of placenta previa using transvaginal sonography (TVS) was compared to that of the traditional transabdominal sonography (TAS). Seventy seven women were scanned by both methods and each sonographic diagnosis was compared to the placental location at delivery. TVS was superior to TAS in diagnosing placenta previa and invariably correct in ruling it out. TVS (and TAS) failed to predict the placental location at delivery only in women diagnosed as having marginal placenta previa prior to 35 weeks gestation. The use of the vaginal probe significantly improved the accuracy of the diagnosis of placenta previa

First trimester gestations of 95 patients were studied by high-frequency transvaginal sonography, which permits the imaging of organs shortly after their development. This new technique has great potential for clinical implementation in such cases as accurate gestational dating and malformation workup

The orientation of the sonographer performing a transvaginal scan is currently based on a concept of anatomical planes, which is customary in transabdominal sonography. We challenge this concept and propose a different approach altogether based on focusing on target organs rather than anatomic planes. The problem of orientation in transvaginal sonography stems from the following: (1) There is a very short distance between the relatively high-frequency transvaginal transducer-probe and the scanned area; a close-up image is generated encompassing a single organ or only part of it. (2) The scanning angle is initially perpendicular to that of abdominal sonography. (3) Transvaginal sonography is an endocavitary dynamic scanning technique. According to the experience in our department (30,000 examinations during the past 4 years) and in two other medical centers, best results from the transvaginal ultrasonographic examination are achieved when the operator searches for every specific organ as the main target, without resorting to pelvic 'planes.' The guidelines for targeted organ scanning and the associated change in orientation are reported together with the limitations. Targeted organ scanning without resorting to 'planes' helps the operator to resolve the problem of orientation during the transvaginal ultrasonographic examination, and to simplify the procedure to a great extent

Recent developments in both laboratory measurements and ultrasound technology have revolutionized the management of early pregnancy. The discriminatory zone concept is a direct result of these developments. By correlating the serum beta-hCG values to the size of an intrauterine gestational sac, a value can be chosen that corresponds to the threshold of visualization of the sac. If the beta-hCG is above this value, a sac must be seen, and if it is not, aggressive steps should be taken to determine whether the pregnancy is abnormal or ectopic. The discriminatory zone may vary among institutions due to different equipment and assays. Thus, its value should be calculated individually at each institution. A proper discriminatory zone and a management protocol such as the one above can eliminate much of the uncertainty in the management of suspected ectopic and early pregnancies