Biomedical subjects
Publications and source records attributed to E H Kagan.
Sonographic and pathologic documentation of 7 cases of intervillous thrombosis of the placenta are presented. These lesions were demonstrated on sonography as early as 19 weeks of gestation. Since intervillous thromboses are thought to be related to Rh isoimmunization, their sonographic documentation may be of clinical importance.
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The normal anatomy of the placenta and the retroplacental area can be well defined with gray scale sonography. The placenta has a characteristic granular echo pattern, with strong echoes emanating from the chorionic plate. After 37 weeks, strong echoes representing calcification may appear; this is a normal physiologic process. The significance of early calcification is unclear. The retroplacental myometrium and venous drainage of the placenta are easily visualized by sonography. Variations in the appearance of the retroplacental myometrium result from different degrees of bladder filling and from uterine contractions. These normal retroplacental structures should not be mistaken for myomas or hematomas.
In cases of abruptio placenta, the ultrasound examination may be negative if external bleeding occurs without a large enouth accumulation of blood to be sonographically visible. A positive sonogram may demonstrate either a retroplacental hematoma or a hematoma that has dissected beneath the chorionic membranes. Six cases of abruptio placenta are presented with sonographic and pathologic findings.
With the advent of gray scale ultrasonography, the internal structure of the placenta can be defined in great detail. Subchorionic sonolucent areas visualized on antepartum sonograms correlate with areas of subchorionic fibrin deposition, hematoma, and cystic degeneration in the term placenta. These lesions are apparently of no clinical significance. However, diffuse intraplacental sonolucent cystic lesions are abnormal and are seen in both hydatidiform mole and hydropic swelling of the placenta.