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To evaluate the impact of endovaginal (EV) sonography in the diagnosis of ectopic pregnancy, a 2 year retrospective study was performed identifying 123 at-risk patients. Of these 123 women, 19 (15.4%) had a surgically proved ectopic pregnancy, only three (15.8%) of which were visualized directly at sonography. A confident diagnosis of an intrauterine pregnancy (IUP) was made at the initial scan in 74%, which contrasts with 58% diagnosed at the first transabdominal (TA) scan in an earlier study from this laboratory, thus confirming an improvement in diagnostic ability with EV transducers. This study has failed to confirm some findings of other workers, particularly that adnexal ring-like structures are visualized frequently in the presence of an ectopic pregnancy. No adnexal rings were observed in our 19 cases. The combination of an adnexal mass and free pelvic fluid was found to correlate best with the presence of an ectopic pregnancy. This study further emphasizes that a significant proportion (26.3%) of ectopic pregnancies have a normal EV sonogram at presentation. The group failing to demonstrate an IUP and showing no evidence of an adnexal mass or pelvic fluid (i.e., a normal pelvic sonogram) carried a 1:3 risk for the presence of an ectopic pregnancy, a result that is very similar to our data published before the introduction of EV technology. We conclude that, although it provides a significant improvement and refinement in the recognition of intrauterine pregnancies, EV scanning does not permit a confident diagnosis of ectopic pregnancy in many cases.

An inability to image the kidneys, severe oligohydramnios, and an empty (nonvisualized) urinary bladder are the most common sonographic findings in fetuses with renal agenesis. The same features, except for the oligohydramnios, are seen in neonates with renal agenesis. Failure to visualize a kidney in the usual flank location with or without demonstration of the kidney in an ectopic location may also be a feature in fetuses or neonates with renal ectopia. The adrenal gland has an unusual but distinctive appearance on longitudinal sonograms in these patients. Sonograms of 23 fetuses and six neonates referred for presumed bilateral or unilateral renal agenesis or ectopia were reviewed retrospectively for the presence of a flattened ("lying down") adrenal gland. At the time of the examination, the adrenal gland was not actively sought as a part of the fetal survey or postnatal examination but was found retrospectively in 48% of these subjects. Although this finding has been described previously, the emphasis was on this observation as a potentially confusing sonographic feature. This manuscript emphasizes the characteristic appearance of the adrenal gland which instead serves as a simple means of confirming that the kidney did not develop in the flank. Detection of a flattened ("lying down") adrenal gland is an observation that should be actively sought in all fetuses and neonates with a presumed diagnosis of renal agenesis or ectopia.

Neural tube defects (NTDs) are among the most common congenital anomalies in the United States, with an estimated prevalence of 16 per 10,000 births. The measurement of amniotic fluid alpha-fetoprotein (AF-AFP) concentration has been used to detect NTDs since the early 1970s. When the AF-AFP concentration is elevated, ultrasonography is commonly used to confirm the presence of a NTD. In this study, patient charts, amniocentesis records, and ultrasound reports from a three-year period were reviewed. The 97 fetuses identified as being at high risk for NTDs were divided into four groups: those with high AF-AFP concentrations (Groups 1 and 2, with from 3 to 5 standard deviations (SD) above the mean and with more than 5 SD above the mean, respectively): those referred from other institutions because of suspicious sonographic results (Group 3); and those at risk because of a previous sibling with a NTD (Group 4). Ultrasonography was 100 per cent sensitive and 100 per cent specific in diagnosing NTDs. Thus, in pregnancies with an elevated AF-AFP concentration, ultrasonography can reliably identify normal fetuses as well as differentiate between those with NTDs and those with other congenital anomalies. Also, since AF-AFP concentrations decline after 20 weeks' gestation, ultrasonography may be a better test than a repeat amniocentesis in equivocal cases of AF-AFP elevation.

To assess the possible relationship between the degree of maternal hydration and the sonographic identification of minimal fetal renal pyelectasis, a prospective study was performed in which fetuses demonstrating mild dilation of the renal pelvis (maximum diameter ranging from 3 to 11 mm) were reexamined after the mothers refrained from oral intake for 12 hours. Complete or almost complete resolution of the pyelectasis occurred in only four of 17 kidneys (23.5 per cent) while the remaining fetal kidneys demonstrated little or no change in the degree of pyelectasis following maternal dehydration. This observation, as well as previous experimental research, suggests that the state of maternal oral hydration is not a major cause of minimal fetal pyelectasis. Additionally, the observation of fetal pyelectasis measuring at least 3 mm in greatest dimension is common, occurring in approximately 18 per cent of fetuses older than 24 menstrual weeks.

Because critical management decisions are based on sonographic estimation of fetal weight in fetuses less than 1000 g, we sought to evaluate the accuracy of birthweight prediction in this range and to identify factors affecting this accuracy. Fetal weight was estimated using several published methods in 53 fetuses with birthweights less than 1000 g. Standard deviations greater than 12.3% indicate more random error in the sonographic weight prediction than has been reported in higher weight groups. No statistically significant differences were found between patient groups with decreased, normal, or increased amniotic fluid volume or portable examination. There was a trend toward lower mean deviation (2.9 vs 6.0%) and standard deviation (8.9 vs. 15.0%) in studies with scan quality judged "good" compared with "poor" based on ability to visualize anatomic landmarks.

The caudate lobe, like the other segments and lobes of the liver, can be defined anatomically as well as pathologically utilizing gray-scale ultrasonography. It is anatomically distinct from the left and right lobes as it has its own portal veins, hepatic arteries, hepatic veins, and bile ducts. Sonographically the limits of the caudate lobe can be defined using readily identifiable vascular landmarks such as the proximal left portal vein anteriorly, the inferior vena cava posteriorly, and the main portal vein inferiorly A wide variety of pathologic conditions that affect the caudate lobe, including cirrhosis, infection, and neoplastic lesions, can be demonstrated by ultrasonography.

The sonograms of 200 randomly selected singleton pregnancies were reviewed. Placental thickness was measured and correlated with menstrual age. The placenta was demonstrated to increase in thickness with advancing menstrual age. At no stage of pregnancy was the normal placenta greater than 4 cm in thickness. Potential pitfalls in measuring placental thickness are addressed, as well as potential causes of aberrations in placental thickness.

We reviewed the sonograms and medical records of all patients who underwent intrauterine transfusions between December 1981 and December 1984 in order to determine the time course for disappearance of the intraperitoneal blood. Seventy-two sonographic examinations were performed on 22 patients who underwent 51 intrauterine transfusions. Nonhydropic fetuses who received less than or equal to 50 cc of intraperitoneal blood exhibited no ultrasonic evidence of intraperitoneal fluid after 8 days. Nonhydropic fetuses receiving greater than 50 cc of intraperitoneal blood showed resolution of intraperitoneal fluid after 12 days. Hydropic fetuses, after intraperitoneal transfusion, all demonstrated persistence of intraperitoneal fluid. Intraperitoneal fluid was seen as long as 24 days after transfusion in hydropic fetuses.

A sonolucent band associated with the fetal abdominal wall is frequently observed in the normal obstetrical ultrasound examination. This band has been labeled pseudoascites because it may closely mimic intraperitoneal fluid. Fifty-three consecutive fetuses were examined sonographically; pseudoascites was evident in 45 fetuses. Sonographic anatomic observations identify pseudoascites as the fetal abdominal wall musculature. The anatomic description of pseudoascites, as well as the difference between pseudoascites and fetal intraperitoneal fluid, are discussed.

The sonograms from 15 patients who underwent 40 intrauterine transfusions at the University of California San Francisco School of Medicine, between December 1981 and December 1984 were retrospectively reviewed. The authors found that 12 to 14 ml of fluid were easily seen in 18- to 20-menstrual-week fetuses and that 30 to 40 ml were seen in fetuses at greater than or equal to 30 menstrual weeks. Since the study was retrospective, the absolute minimum of detectable fetal intraperitoneal fluid was not recorded for each fetus. The above represent amounts that were consistently documented during each intrauterine transfusion. In order to gain information about the minimum detectable fetal intraperitoneal fluid, two fetuses undergoing intraperitoneal transfusions were studied prospectively. The minimum fetal intraperitoneal fluid volumes observed were 10 ml in a 22-week fetus and 15 ml in a 26-week fetus.

It has been demonstrated by autopsy and by ultrasonography that the fetal left hepatic lobe is proportionately larger than that in the adult, probably because of increased supply of oxygenated blood from the umbilical vein. Intrauterine growth retardation (IUGR) is associated with impairment of the fetal blood supply, and might affect the left lobe disproportionately. The authors evaluated the relative size of the lateral segment of the fetal left lobe (L) compared with the remainder of the liver (R) in 88 obstetrical sonograms from 53 patients with IUGR. There was no statistically significant difference in the mean ratio of L/R between normal and IUGR fetuses. There was also no evidence of decreasing L/R in IUGR fetuses with serial examinations. The L/R ratio does not discriminate between normal fetuses and those with IUGR.