Obstetric Imaging

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Absent double decidual sign with MSD >10 mm prediCtors of poor outCome in first trimester 
Anterior uterine wall displaced away from fetal body normal amniotiC fluid
Volume
Several methods are used for assessment of fluid; there is no evidence that any method is better than the other:
• Subjective assessment (recommended by most sonographers)
Anterior uterine wall displaced away from fetal body (good sign)
Banana sign (spina bifida) Banana sign (spina bifida), Posterior fossa
Cerebellar view
• Banana sign (Fig. 10-28): represents the cerebellum wrapped around the posterior brainstem secondary to downward traction
of the spinal cord as part of Arnold-Chiari malformation
• Most cases of spina bifida are suspected because of head abnormalities (e.g., banana sign).
Double decidual sac sign Pregnancy?
• Visualize gestational sac
• Double decidual sac sign

Double Decidual Sac Sign (Fig. 10-6)
The double decidual sac sign is a useful early sign of IUP. It is based on the demonstration of three layers
of different echogenicity:
• Decidua parietalis (hyperechoic)
• Fluid in the uterine cavity (hypoechoic)
• Decidua capsularis (hyperechoic)
The double-bleb sign refers to the presence of an amnion and yolk sac at 5 to 6 weeks. The embryo lies between these two structures.

• Pseudogestational sacs have an absent double decidual sign.
• No double decidual sign but rather a single rim of echoes around pseudogestational sac seen in ectopic pregnancy
Double Decidual Sac Sign The double decidual sac sign is a useful early sign of Intra uterine pregnancy. It is based on the demonstration of three layers of different echogenicity:
• Decidua parietalis (hyperechoic)
• Fluid in the uterine cavity (hypoechoic)
• Decidua capsularis (hyperechoic)
Double-bubble sign • Double-bubble sign (can be seen as early as 24th week of gestation)

duodenal atresia
fluid around urinary bladder US Features of Hydrops Fetalis
• Effusions
Ascites (fluid around urinary bladder) is the
first and most reliable sign.
Gross Polyhydramnios Gross polyhydramnios has a higher association with fetal anomalies than mild polyhydramnios. Associated anomalies include anencephaly, encephalocele, GI obstructions, abdominal wall defects, achondroplasia, and hydrops (isoimmunization). 
Interstitial line sign Interstitial line sign: hyperechoic endometrial
line abuts but does not surround sac
Lambda sign • Lambda sign: chorion extending into intertwin membrane

Dichorionicity
Lemon Sign • Chiari II, myelomeningocele
• Encephalocele
Lemon sign (skull deformity) • Lemon sign (skull deformity)
enCephaloCele

Indirect signs
• Lemon sign (Fig. 10-27): bifrontal indentation. In 90% of fetuses with spina bifida <24 br="" weeks.=""> In older fetuses (24 to 37 weeks), lemon sign disappears. Lemon sign is rarely seen in a normal fetus.

spina bifida and myelomeningoCele

Lemon Sign
• Chiari II, myelomeningocele
• Encephalocele
Oreo cookie sign • Adrenal glands can be mistaken for kidneys (hypoechoic rim, echogenic center: Oreo cookie sign
separating amnion • Failure to identify a separating amnion is not a reliable sign to diagnose monoamnionicity.
Spalding's sign fetal death
• No fetal heart beat
• Absent fetal movement
• Occasional findings:
Overlapping skull bones (Spalding's sign)
Gross distortion of fetal anatomy (maceration)
Soft tissue edema: skin >5 mm
The double-bleb sign The double-bleb sign refers to the presence of an
amnion and yolk sac at 5 to 6 weeks. The embryo lies
between these two structures.
The double-bleb sign  The double-bleb sign refers to the presence of an amnion and yolk sac at 5 to 6 weeks. The embryo lies between these two structures.
Tubal ring sign (95% chance of ectopic Tubal ring sign (95% chance of ectopic): echogenic
rim surrounding an unruptured ectopic
pregnancy
Twin peak sign Twin peak sign

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