A two-stage protocol for evaluating women at high risk for placenta accreta, which uses ultrasonography first, and then MRI for cases with inconclusive ultrasound features, will optimize diagnostic accuracy.

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We have examined age-related changes in segments of common carotid (Com), basilar (Bas), posterior communicating (PC), and middle cerebral (MC) arteries taken from 14 near-term fetal lambs, 62 newborn lambs 3-7 days old, and 42 adult nonpregnant sheep. Transition from fetal to newborn life was associated with a decreased water content in all arteries ranging from 0.6% (Com) to 2.3% (Bas), no change in the relative content of cellular protein, an increase in wall thickness ranging from 4% (MC) to 26% (Com), an increase in maximum contractile tension ranging from 18% (MC) to 82% (Com), an increase in stiffness, an increase in the maximum active stress ranging from 6% (Bas) to 43% (Com), a decrease in the amine-to-potassium ratio (calculated as the maximum response to 10 microM serotonin with 20 microM histamine divided by the maximum response to 122 mM K+) ranging from 8% (Bas) to 51% (Com), and a decrease in the norepinephrine-to-potassium ratio ranging from 2.1% (Bas) to 56% (Com). Thus developmental changes associated with the transition from fetal to newborn life were much more pronounced in the larger, more proximal Com than in the smaller, more distal cerebral arteries, suggesting that, at term, the cerebral arteries are more mature both functionally and structurally than the Com arteries. Similarly, the transition from newborn to adult life was associated with much greater changes in Com characteristics than with those of the cerebral arteries. These studies demonstrate that the effects of aging vary considerably along the cerebrovascular tree and that conclusions based on developmental studies of large systemic arteries cannot be freely extrapolated to the smaller arteries of the circle of Willis.

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The purpose of this paper is to investigate, identify and discuss artifacts and their sources arising in threedimensional ultrasound (3D US) in clinical practice in order to increase the awareness of clinicians and sonographers with respect to common 3D US artifacts and to use this increased awareness to avoid or reduce the occurrence of misdiagnosis in 3D US studies. Patient 3D US data were acquired using several different scanners and reviewed interactively on the scanner and graphics workstations. Artifacts were catalogued according to artifact origin. Two-dimensional ultrasound (2D US) artifacts were classified whether they were of a B-mode or color/power Doppler origin and their presentation in the original scan planes and the resulting volume re-sliced planes and rendered images was identified. Artifacts unique to 3D US were observed, noted and catalogued on the basis of whether they arose during acquisition, rendering or volume editing operations. Acoustic artifacts identified included drop-out, shadowing, etc. whose presentation depended on the relationship between slice and imaging plane orientation. Color/ power Doppler artifacts were related to gain, aliasing, and flash which could add apparent structure or confusion to the volume images. Rendered images also demonstrated artifacts due to shadowing and motion of adjacent structures, cardiac motion or pulsatility of the cardiac septum or vessel walls. Editing artifacts potentially removed important structures.

In the fetus and infant, high-altitude hypoxemia is associated with increased cerebrovascular morbidity. To test the hypothesis that this increased morbidity involves changes in cerebrovascular endothelial and smooth muscle function, we examined middle cerebral, posterior communicating, basilar, and common carotid arteries obtained from 23 normoxic fetuses, 19 hypoxemic fetuses maintained at high altitude (3,820 m) from 30 days gestation to near term (approximately 143 days), 55 normoxic non-pregnant adults, and 24 hypoxemic nonpregnant adults maintained at the same altitude and duration as the hypoxemic fetuses. Long-term hypoxemia was associated with several significant changes in both fetal and adult arteries, including a generalized increase in base-soluble protein (5-50%), a depression of the maximum potassium-induced tensions (16-49%), and a depression of the relaxation responses to S-nitroso-N-acetylpenicillamine (1-11%), which releases nitric oxide into solution upon hydration. Altitude acclimatization significantly enhanced amine-to-potassium ratios (the ratio of tension produced by 10 microM serotonin with 20 microM histamine to that produced by 122 mM potassium) only in adult cerebral arteries (51-87%) and significantly depressed potassium-induced stresses (up to 41%) and serotonin/histamine-induced tensions (20-37%) only in fetuses. Endothelium-dependent relaxations to A23187 were significantly depressed in hypoxemic fetuses (4-11%) but were significantly enhanced in hypoxemic adults (2-14%). We conclude that chronic hypoxemia depresses both vascular smooth muscle and endothelial function to a greater extent in fetal than in adult cerebral arteries and that this effect could contribute to the greater postnatal vulnerability to asphyxic and hypertensive insults seen in hypoxemic neonates.

Participation in assessment alone may have been sufficient to encourage behavioral change even without the web-based SBIRT intervention. Randomization to the SBIRT did not result in a significantly different change in risky drinking behaviors. The importance of perception of other women's drinking and one's own depression/functionality may have implications for future interventions.

Our study attempted to identify whether sonographic markers for placenta accreta may be present as early as the first trimester. We reviewed 10 cases with pathologically proven accreta and retrospectively analyzed their first-trimester images. The gestational ages ranged from 8 weeks 4 days to 14 weeks 2 days. Sonographic findings included anechoic placental areas (9 of 10), low implantation of the gestational sac (9 of 10), an irregular placental-myometrial interface (9 of 10), and placenta previa (7 of 10). Nine patients had at least 1 prior cesarean delivery; 3 had additional uterine surgical procedures. One patient underwent hysteroscopic myomectomy. Our case series suggests that signs of placenta accreta may be present in the first trimester.