Diagnostic ultrasound ( PDFDrive )

CHAPTER 43 Sonographic Evaluation of the Placenta 1489
A
B
C
FIG. 43.36 Mimic of Vasa Previa. (A) Transvaginal color
Doppler demonstrates an apparent vessel overlying the internal
cervical os with the fetal cranium closely opposed to the cervix.
(B) Color Doppler sonogram of the internal cervical os with
manual displacement of the fetal head from the internal cervical
os demonstrating no vasa previa. (C) Gray-scale sonogram
demonstrating no vessels overlying the cervix (indicated by
calipers).
demonstrated. However, lack of low does not exclude RPOC.
Care should be taken not to mistake vascularized RPOC for
a uterine arteriovenous malformation, because prominent low
can be seen in RPOC. 190 In fact, the association of an endometrial
mass with prominent blood low strongly suggests RPOC. 191,192
Endometrial measurements less than 10 mm suggest the absence
of RPOC, especially in the absence of blood low, with high
negative predictive values. 193 Calciications in the endometrial
mass are highly suggestive of RPOC. hese calciications
represent normal placental maturation that occurred during
pregnancy.
FIG. 43.37 Funic Presentation. Transvaginal ultrasound of a single
loop of normal umbilical cord, free loating and overlying the internal
cervical os. The cervix is indicated by the calipers. The three vessels of
the umbilical cord are seen in cross section.
CONCLUSION
Multiple abnormalities associated with placental development
and function can be identiied by prenatal sonography. Sonographers
and sonologists need to understand the basic anatomy
and physiology of the placenta so that abnormal indings on
prenatal sonography can be acknowledged, to achieve the best
possible outcome for mother and neonate.