High-resolution ultrasound (US) and pathologic analysis were used to define the relationship between placental hypoechoic-anechoic areas, frequently seen in the third trimester, and the clinically significant entity of placental infarction. Placentas were obtained from three groups of patients: those prospectively demonstrating one or more placental hypoechoic-anechoic areas greater than or equal to 1 cm in diameter on third-trimester sonograms (n = 14), those with risk factors for vascular disease (n = 12), and control patients without risk factors (n = 16). Pathologic analysis demonstrated significantly more infarcts in patients with risk factors than in control patients (17 vs three, P = .047). Of a total of 22 infarcts from all three groups, 19 (86%) were isoechoic to viable placenta and therefore not detected with US. The three infarcts identified with US contained hypoechoic or anechoic foci of fibrin or hemorrhage. Of 26 placental hypoechoic-anechoic areas 23 (88%) were decidual septal cysts or intervillous thrombosis without infarction. The authors conclude that nonhemorrhagic placental infarction cannot be identified with ex utero US and, by inference, that prenatal US is probably insensitive for detection of placental infarction.
To define the relative merits of radiographic and ultrasonic cholecystography, we studied 208 randomly selected patients with possible cholelithiasis. The patients underwent both procedures, and the results were interpreted in blind fashion. Two hundred patients had satisfactory confirmation of their diagnosis, by either a well visualized radiographic cholecystogram or operation or both. The overall accuracy of the ultrasonic examination was 93 per cent, with a false-negative rate of 11 and an indeterminate rate of 4 per cent. The indeterminate rate was 24 per cent for the single-dose oral cholecystogram and 8 per cent for the double-dose oral cholecystogram. Both ultrasonic cholecystography and radiographic cholecystography are useful to detect gallstones. Our findings support using single-dose oral cholecystography as the routine first examination. If the gallbladder is not satifactorily visualized, ultrasonic cholecystography can be performed immediately. In an emergency or for patients who might be pregnant, ultrasonic cholecystography is available as the initial examination.
Seven cases of triploidy were encountered by the Prenatal Diagnosis Program at Dartmouth-Hitchcock Medical Center over an 8-year period through associated pregnancy complications. We describe the characteristic findings that facilitate prenatal diagnosis and management. Our experience includes fetuses with major central nervous system abnormalities (spina bifida aperta, holoprosencephaly) and anterior abdominal wall defects, which are detectable with routine prenatal diagnostic screening examinations (ultrasound and AFP). In addition, we stress the importance of recognizing obstetric complications and associated cystic placental changes, which are quite common among triploid conceptuses. Molar changes associated with triploidy have a more benign prognosis than that associated with diploid moles. Such molar changes may relate to the presence of a diploid paternal chromosome complement. The usefulness of cytofluorometric DNA determinations in helping to confirm a clinical suspicion of triploidy is emphasized. These cases are presented in an effort to facilitate prenatal recognition and management of this common cytogenetic condition and prevent unnecessary Caesarean section deliveries.
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