An eccentrically-located gestational sac towards the fundus of the uterus is the normal sonographic appearance; however, an abnormally eccentric gestational sac on ultrasound may be apparent due to a number of causes
interstitial ectopic pregnancy 1
normally implanted pregnancy i...
In a fetal sonographic assessment, an absent nasal bone is a feature that can sometimes be used as a surrogate marker for fetal aneuploidy.
It is assessed on a midline sagittal view. In this section, the nasal bone is often seen as a bright echogen...
Apple-peel intestinal atresia, also known as type IIIb or Christmas tree intestinal atresia, is a rare form of small bowel atresia in which the duodenum or proximal jejunum ends in a blind pouch and the distal small bowel wraps around its vascular supply in a spiral resembling an apple peel. Oft...
The banana sign is one of the many notable fruit inspired signs.
This sign is seen on axial imaging through the posterior fossa of fetuses with associated conditions such as Chiari II malformation and/or spina bifida.
In Chiari II malformation, the banana sign describes the way the cerebellum...
Bunch of grapes sign refers to the imaging appearance of multiple cystic spaces or lesions and it has been described for multiple pathologies:
bunch of grapes sign (hydatidiform mole) 7
bunch of grapes sign (bronchiectasis) 3
bunch of grapes sign (IPMN) 6
bunch of grapes sign (botryoid rhabd...
The butterfly sign refers to the normal appearance of the choroid plexuses on axial imaging of the fetal brain, commonly observed on the antenatal ultrasound. Its absence may suggest holoprosencephaly 1.
In the CNS, the term should not be confused with a butterfly glioma, which is a glioblastom...
Chorionic bump is a finding that can be uncommonly seen in a first-trimester scan. It may represent a small hematoma bulging into the gestational sac or an anembryonic (failed) second pregnancy that is being resorbed. It is also seen in some patients undergoing infertility treatment.
Cloverleaf skull, also known as kleeblattschädel syndrome or deformity, refers to a type of severe craniosynostosis which gives the skull a cloverleaf shape. It is very rare, with less than 130 case reports globally. It typically results from intrauterine premature closure of the sagittal, coron...
There are several described cockade signs in radiology:
cockade sign (intraosseous lipoma)
cockade sign (aorto-left ventricular tunnel) 1
cockade sign (appendicitis) 2
cockade sign (hypertrophic pyloric stenosis) 3
cockade sign (GI tumors) 4
Congenital hallux valgus is a very rare finding wherein a fetus or newborn shows lateral deviation of the first toe(s). When found on prenatal imaging, bilateral congenital/foetal hallux valgus is highly suggestive of fibrodysplasia ossificans progressiva 1,2.
A double bleb sign is a sonographic feature where there is visualization of a gestational sac containing a yolk sac and amniotic sac giving an appearance of two small bubbles 2. The embryonic disc is located between the two bubbles. It is an important feature of an intrauterine pregnancy and thu...
The double decidual sac sign (DDSS) is a useful feature on early pregnancy ultrasound to confirm an early intrauterine pregnancy (IUP) when the yolk sac or embryo is still not visualized. It consists of the decidua parietalis (lining the uterine cavity) and decidua capsularis (lining the gestati...
Echogenic fetal bowel is an observation in antenatal ultrasound imaging, in which fetal bowel appears to be brighter than it is supposed to be. It is a soft marker for trisomy 21 and has several other associations. When observed, it needs to be interpreted in the context of other associated abno...
The empty amnion sign is a sonographic observation where there is the visualization of an amniotic sac without concomitant visualization of an embryo. It is an indicator of pregnancy failure regardless of the mean sac diameter and is considered to have a sufficiently high positive predictive val...
The expanded amnion sign has been described as a poor prognostic sign in early pregnancy, suspicious though not diagnostic of failed early pregnancy. Any visible embryo that is surrounded by an amnion (visible on transvaginal ultrasound) should also have a heartbeat, regardless of crown-rump len...
Fetal cardiothoracic (C/T) circumference ratio is a parameter than can be used in assessment of fetal cardiac and thoracic/chest wall anomalies. It is the ratio of the cardiac circumference to the thoracic circumference and may be easily measured on fetal ultrasound/echocardiography.
Fetal maceration is one of the signs of fetal death. It is a destructive aseptic process that appears between 12 to 24 hours after fetal death. It may not be seen in a pregnancy earlier than 6 months. In this a separation of the skin from head and trunk occurs giving a bubble-like appearance.
A floating head appearance refers to imaging features observed typically on antenatal ultrasound with certain skeletal dysplasias such as achondrogenesis.
Against the background of a poorly-mineralized spine, a normally ossified skull is seen giving an impression of a floating head.
Cervical funnelling is a sign of cervical incompetence and represents the dilatation of the internal part of the cervical canal and reduction of the cervical length.
Greater than 50% funnelling before 25 weeks is associated with ~80% risk of preterm delivery.
Hanging noose sign in obstetric imaging is a rarely described but classical finding of a true umbilical cord knot. It demonstrates a transverse section of the umbilical cord surrounded by a loop of umbilical cord and changes in the pressure of the knot can be demonstrated with the fetal movement...
The interstitial line sign is an ultrasound finding in interstitial ectopic pregnancy. It is an echogenic line from the mass to the endometrial echo complex. Reportedly it has high sensitivity (80%) and specificity (98%).
Intradecidual sac sign (IDSS) is a useful feature in identifying an early intrauterine pregnancy (IUP) as early as 25 days of gestation 1. The threshold level (earliest one can see the sign) is 24 days of gestation and the discriminatory level (one should always see the sac) is 47 days. As per t...
There are two described lambda signs:
lambda sign (twin pregnancy)
lambda sign (sarcoidosis)
The lemon sign, noted on antenatal imaging, is one of the many notable fruit-inspired signs. It is a feature when there appears to be an indentation of the frontal bone (depicting that of a lemon). It is classically seen as a sign of a Chiari II malformation and also seen in the majority (90-98%...
Platyspondyly is a radiographic sign and refers to flattened vertebral bodies throughout the axial skeleton.
Platyspondyly can be feature of many conditions which include:
severe Gaucher disease 1
A pseudodysraphism refers to the splayed appearance of a normal spine created due to excessive craniocaudal angulation during sonographic evaluation. This can erroneously lead to the diagnosis of a spinal neural tube defect.
A pseudogestational sac, also known as a pseudosac or intra-cavitary fluid, is the concept that a small amount of intrauterine fluid in the setting of a positive pregnancy test and abdominal pain could be erroneously interpreted as a true gestational sac in ectopic pregnancy.
The sign was origi...
Pseudo-omphalocele is a spurious sonographic appearance giving an impression of an anterior abdominal wall defect.
Pseudo-omphalocele may be seen in:
scanning errors where there is a deformation of the fetal abdomen by transducer pressure and the im...
Roberts sign refers to the presence of a gas shadow within the heart or the greater vessels, in cases of fetal death in utero. It is a rare sign caused by postmortem blood degeneration, usually seen 1-2 days after death; and may be seen as early as 12 hours.
History and etymology
Shortening of the uterine cervical canal as the name implies refers to an abnormal shortening of the uterine cervical length. It is considered a sign of cervical incompetence during pregnancy and can lead to premature delivery.
primary (i.e. congenital/idiopathic)
Snowstorm sign in obstetric imaging is classically seen in complete hydatiform mole. It is characterized by the presence of many hydropic villi which gives the ultrasonographic appearance of a central heterogeneous mass having a solid, hyperechoic area and interspersed with a multitude of cystic...
Snowstorm sign may refer to:
snowstorm sign: complete hydatiform mole (ultrasound)
snowstorm sign: extracapsular breast implant rupture (ultrasound)
snowstorm sign: thyroid pulmonary metastases (chest radiograph)
The Spalding sign refers to the overlapping of the fetal skull bones caused by collapse of the fetal brain. It appears usually a week or more after fetal death in utero.
This finding was originally described by Alfred Baker Spalding (1874-1942), an American obstetrician 2, on abdominal radiogr...
Strawberry skull refers to the shape of the head on an antenatal ultrasound.
In general, strawberry skull is considered one of the non-specific 'soft markers' for abnormal fetal development. It is considered more closely associated with trisomy 18 (Edward syndrome).
A telephone receiver deformity is a characteristic bowing of the shaft of the long bones, usually the humeri or femora, seen in thanatophoric dysplasia.
The T sign has been described in several different pathologies:
T sign (obstetrics)
upper T sign (brain)
lower T sign (brain)
The "T sign" is really the absence of a twin-peak sign (or lambda (λ) sign) and is used in ultrasound assessment of a multifetal pregnancy.
It refers to the lack of chorion extending between the layers of the intertwin membrane, denoting a monochorionic pregnancy. The intertwin membrane comes t...
Tubal ring sign also referred to as bagel sign or blob sign, one of the ultrasound signs of a tubal ectopic. It comprises an echogenic ring that surrounds an unruptured ectopic pregnancy. It is said to have a 95% positive predictive value (PPV) for ectopic pregnancy.
The twin peak sign (also known as the lambda (λ) sign) is a triangular appearance of the chorion insinuating between the layers of the intertwin membrane and strongly suggests a dichorionic twin pregnancy. It is best seen in the first trimester (between 10-14 weeks) 5. While the presence of a tw...