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Objectives: To examine the ultrasonographic feasibility of imaging the fetal pons and to construct a reference chart for its normal development during gestation. Methods: A cross-sectional, prospective study on 293 healthy fetuses of low-risk pregnancies between 19 and 34 weeks was performed. The transfontanel approach, via the abdominal or vaginal routes, was used to evaluate the fetal metencephalon (pons and cerebellum). The anteroposterior diameter of the fetal pons was measured in a mid-sagittal plane. The longitudinal diameter of the cerebellar vermis was measured at the same plane and the vermis-pons ratio (VPR) was established. Results: One hundred and forty-four fetuses were in vertex position. In 140 (97.2%) satisfactory visualization and measurements of the pons and cerebellar vermis were obtained. One hundred and forty-nine fetuses were breech presentations and measurements were successfully performed in 147 (98.6%). The pons anteroposterior and vermis longitudinal diameters showed a linear correlation with gestational age (GA) (r = 0.95 for both measurements; P < 0.001). The mean VPR was 1.5 (+/-0.1 SD) and did not change in the gestational interval that was considered. Conclusion: By using the transfontanel approach, evaluation of the fetal pons is feasible via the mid-sagittal plane. The nomograms developed and the ratio to fetal vermis provides reference data that may be helpful when evaluating anomalies of the brainstem. [ABSTRACT FROM AUTHOR]

Objective To describe our management of pregnancies complicated by twin reversed arterial perfusion (TRAP) sequence. Methods This was a retrospective study involving all cases of TRAP sequence referred to our fetal medicine unit in a 3-year period (2000–2002). Patients were routinely managed by repeat sonographic surveillance with sonographic anatomical evaluation and detailed echocardiography. Cases with signs of impending cardiac failure were treated by in-utero YAG-laser coagulation of the umbilical vessels of the acardiac twin. Results Six cases were studied. Three patients in whom there were no signs of deterioration in the status of the pump twin, and in whom the acardiac twin was smaller than the pump twin, were managed conservatively. However, one of these with monoamniotic twins ended in intrauterine fetal death of the pump twin. The other two cases presented with spontaneous cessation of blood flow in the umbilical artery of the acardiac twin. Both delivered at term normal neonates whose follow-up revealed no signs of neurological sequelae. One case of quadruplet pregnancy (with TRAP sequence and two dichorionic twins) was treated by selective termination of the monochorionic twins. Two cases with signs of impending cardiac failure were treated by in-utero YAG-laser occlusion of the vessels in the acardiac mass. Both interventions had a favorable outcome. Conclusions Conservative treatment is suitable for milder cases of TRAP sequence in which the pump twin is the larger one. Cases in which the acardiac twin is larger have a poorer prognosis and should be treated by invasive intervention and cord occlusion. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective To establish a nomogram for fetal vermis measurements during gestation. Methods A prospective cross-sectional study of normal singleton pregnancies. Measurements of the fetal vermis width (in the axial plane) and height (in the sagittal plane) were performed by high-resolution transabdominal ultrasonography between 18 and 38 weeks of gestation in 256 fetuses. Results Adequate vermis measurements were obtained in 256 fetuses. Vermian width and height as a function of gestational age and biparietal diameter were expressed by regression equations and the correlation coefficients were found to be highly statistically significant (P < 0.0001). The normal mean (± SD) for each gestational week was defined. Conclusions The present data offer the normal range of the vermian measurements throughout gestation. These values may allow intrauterine assessment of the development of the cerebellar vermis, as well as the posterior fossa. [ABSTRACT FROM AUTHOR]

Objective: To assess in utero visualization of the middle phalanx of the fifth digit (MPFD) between 13 and 17 weeks of gestation. Methods: This was a prospective cross-sectional study in which women attending for fetal sonographic examination between 13 + 0 and 17 + 6 weeks of gestation were evaluated for the presence of the middle phalanx of the fifth digit (MPFD). A total of 682 fetuses with normal findings on first-trimester anatomical examination were recruited. Using transvaginal multifrequency 4-8 and 5-9 MHz probes, the fifth finger was examined in both axial and lateral views until optimal visualization of the MPFD was achieved. Results: The MPFD was visualized in 14.3% (2/14) of cases at 13 weeks, 70.3% (154/219) at 14 weeks, 82.2% (240/292) at 15 weeks, 97.4% (111/114) at 16 weeks and 100% (43/43) at 17 weeks of gestation. Conclusions: Ultrasound visualization of the MPFD gradually increases during the 13- to 17-week period. This emphasizes the limited role of non-ossification of the MPFD as a sonographic marker of Down syndrome before 17 weeks of gestation. [ABSTRACT FROM AUTHOR]

An abstract of the conference paper "Examining the vermis: A better and easier way," by O. Shen and colleagues is presented.