Reproducibility in the assessment of postmenopausal ovaries with transvaginal ultrasound.

OBJECTIVE: The goal of this study was to evaluate the interexaminer variation in the assessment of postmenopausal ovaries using transvaginal ultrasound (TVU). METHODS: One hundred eighty-eight cancer screening trial participants undergoing TVU were reassessed by a second TVU examination. RESULTS: Although first examiners tended to describe significantly larger left (P < 0.001) but smaller right (P = 0.036) ovaries, as well as fewer ovarian abnormalities, examiners agreed on the test interpretation 93% of the time (kappa = 0.846). In only two cases (1%) were the differences in interpretation such that the two examiners recommended different follow-up procedures. CONCLUSIONS: Because of the high fatality rate of ovarian cancer, early detection remains the best way to combat this devastating disease. TVU is one screening technique we are currently evaluating in a cancer screening trial. To help ensure screening test reproducibility, we have followed explcit protocols for training and certifying all TVU examiners, as well as for conducting TVU examinations. This study demonstrates that by adhering to specific training, certification, and examination protocols, TVU reproducibility is excellent. Such protocols may well serve as a standard for TVU training and examination.

The sonographic assessment of twin growth discordancy.

OBJECTIVE: To determine: 1) the frequency with which standard fetal biometry (head circumference [HC], abdominal circumference [AC], and femur length [FL]) and the transverse cerebellar diameter can be measured in twin pregnancies; and 2) the efficacy of fetal biometry using these measures in the detection of twin growth discordancy. METHODS: The study population consisted of 203 twin pregnancies reviewed retrospectively. The frequency with which standard biometry and the transverse cerebellar diameter could be obtained was recorded. Forty-nine twin pairs who were delivered within 3 weeks of their last ultrasound examination were divided into three groups based on birth weight differences: 20% or more, 10-19%, and less than 10%. The sensitivity, specificity, and predictive values of the specific fetal biometric measurements and of the sonographic estimation of fetal weight were assessed for this subgroup for the prediction of twin discordancy. RESULTS: The FL could be measured consistently throughout gestation, but the ability to measure the AC decreased after 35 weeks' gestation. The frequency with which HC and transverse cerebellar diameter could be measured decreased with advancing gestation. The transverse cerebellar diameter could be measured only in 91 of 151 and 14 of 49 pregnancies at 31-35 and 36-40 weeks' gestation, respectively. An intra-pair AC difference of 20 mm or more had a sensitivity and a positive predictive value of 83% for the detection of twin discordancy, defined as at least a 20% difference in birth weight. Estimated fetal weight had a sensitivity and positive predictive value of 92.9 and 72%, respectively. In contrast, a difference of 4 mm or more in the intra-pair transverse cerebellar diameter had a sensitivity of 28% and a positive predictive value of 50% in detecting twin weight discordancy. CONCLUSIONS: Appropriate twin fetal biometry can be measured throughout gestation. Estimated fetal weight has a higher sensitivity but a lower positive predictive value than AC for predicting twin growth discordancy.

Composite assessment of gestational age: a comparison of institutionally derived and published regression equations.

OBJECTIVES: This study was undertaken to evaluate (1) the applicability of previously reported regression equations for gestational age assessment to our patient population in Pittsburgh and (2) whether the addition of radius length or its substitution for one of the other fetal measurements could improve the prediction of gestational age. STUDY DESIGN: Five fetal parameters--biparietal diameter, head circumference, abdominal circumference, femur length, and radius length--were measured in a prospective cross-sectional study of gestational age assessment in 265 pregnant women between 13 and 43 weeks' gestation. RESULTS: The regression equation derived for each fetal parameter was found to be quite similar to previously published reports. Although the coefficient of determination was only minimally affected, the variability improved with the institutionally derived regression equation. CONCLUSION: The incorporation of several fetal measurements into a composite assessment of gestational age generally enhances the accuracy of the prediction. The addition of a second long bone to a gestational age assessment does not significantly improve results.

Rapid assessment of fetal hemoglobin concentration with the HemoCue system.

Successful treatment of severe fetal hemolytic disease depends on rapid and accurate measurement of fetal hemoglobin or hematocrit. The HemoCue is a portable hemoglobinometer that rapidly measures hemoglobin concentration. To evaluate the potential role of this instrument in fetal transfusion therapy, we measured hemoglobin concentration with the HemoCue and compared it with Coulter counter determination of hemoglobin in 39 fetuses. The HemoCue accurately measured fetal hemoglobin concentration (y = -0.3986 + 1.0276x; r = 0.97, P less than .001). This instrument is valuable for use with intravascular fetal transfusions.

Fetal radius length: a critical evaluation of race as a factor in gestational age assessment.

Growth of the fetal radius was examined ultrasonographically in a prospective cross-sectional study of 290 white and 63 black patients between 12 and 43 weeks' gestation. The mean of radius length and 95% predictive intervals were calculated for each week. The most efficient description of the data was given by a simple log-linear model. The slopes for the white and black study groups estimated were distinctly different. Consequently, a single equation was estimated that considers race when assessing gestational age from radius length.

Sonographic assessment of the first trimester fetus. A cautionary note.

Ultrasound has the potential for diagnosing fetal abnormalities in utero with a high degree of accuracy. During the first trimester, peculiarities of fetal development may suggest to the novice sonographer an abnormality where one does not exist. Similarly, particular anatomic structures may appear normal in the first trimester, yet evolve into an obvious abnormality later in gestation. For these reasons, the ultrasonic diagnosis or exclusion of a congenital anomaly in the first trimester should be made only with caution.

Two-dimensional echocardiographic assessment of normal fetal cardiac anatomy.

The fetal heart is visualized routinely during the antepartum ultrasound examination. Because of the advent of high-resolution, real-time ultrasound instruments, details of fetal cardiac anatomy can now be defined. Fifty consecutive fetuses were examined in utero to assess the ability of two-dimensional echocardiography to define intracardiac anatomy at various gestational ages. A complete examination required at least three standard echocardiographic views of the heart: four-chamber, short-axis and long-axis views. In 30 of the 50 fetuses studied (60%) only one examination was necessary to obtain this information. Ten patients had a second examination later in gestation that complemented the findings of their first study. In all but two fetuses, detection of all four cardiac chambers and at least one semilunar valve was possible. Mitral-semilunar valve continuity was detected in all. The quality of echocardiographic imaging was enhanced by the fetal occiput posterior position (three views obtained in 83% of the fetuses studied). Breech position did not affect imaging quality. Prior to 30 weeks of gestation, fetal movement hampered analysis of fetal cardiac anatomy in some patients.

Ultrasonic assessment of subsequent unexplained infertility after ovulation induction.

The development of ovarian follicles was studied ultrasonographically in 21 cycles in eight infertile patients with the diagnosis of ovulatory dysfunction in whom conception did not occur after the defect had apparently been corrected. Pelvic ultrasound demonstrated three patterns in 20 of the 21 cycles studied: ovarian hyperstimulation in seven cycles; follicular atresia before ovulation in three cycles; persistent unruptured follicular cysts in 10 cycles. Recognition of these patterns has been helpful in modifying therapy in infertile patients.