Abnormal radiological signs in Obstetrics


Bagel sign:

Ultrasonographic sign of ectopic pregnancy.

Ultrasound image demonstrating ‘Bagel’ sign. The broken arrow depicts the right ovary and the solid arrow shows ectopic pregnancy characterized by the ‘Bagel sign’.


Robert’s Sign:

Earliest radiological sign of intrauterine fetal death (12 hr). X-ray shows presence of gas in the fetal great vessels.

Spalding Sign:

Sign of intrauterine fetal death (IUFD). Overlapping of skull bones after fetal demise. Observed by USG.

Banana Sign:

Ultrasound sign in open spina bifida. Shows abnormal anterior curvature of cerebellum. This is a tell tale sign of a shallow posterior fossa anomaly or Chiari malformation.

Lemon Sign:

Ultrasound sign in open spina bifida. Shows typical frontal ‘pinching’ of calvarium. Due to associated Arnold-Chiari malformation.

Single bubble sign:

Seen in congenital hypertrophic pyloric stenosis (CHPS). Single bubble: Hugely dilated stomach due to pylorus obstruction.

Double bubble sign:
Seen in duodenal atresia.
Larger, proximal bubble: Dilated stomach. Distal, smaller bubble: Dilated proximal duodenum.

Lambda (Twin peak) Sign:

Ultrasonographic sign seen in dichorionic pregnancies.

T’ Sign:

Ultrasonographic sign seen in monochorionic twins.

Stuck Twin Sign:
Seen in twin twin transfusion syndrome. Due to the severe oligohydramnios, smaller twin is held in a fixed position along the uterine wall.

Buddha sign:
Seen in hydrops fetalis. Halo around the baby’s head due to scalp edema.

Key hole sign: Seen in Posterior urethral valve.

Frog’s eye sign:

Seen in anencephaly (earliest congenital anomaly to be picked up by USG).

Hockey Stick sign:

Sign of fetal macrosomia (expected weight of ≥4 kg).

Signs of complete mole:


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