The Jarcho-Levin syndrome (JLS) or spondylothoracic dysostosis is a rare autosomal recessive heterogeneous disorder which can occur to variable severity. Previously the condition spondylocostal dysostosis was also considered as part of the JLS spectrum but is now considered a distinct pathologic...
The uterus is a hollow, thick-walled, muscular organ of the female reproductive tract that lies in the lesser pelvis.
The uterus has an inverted pear shape. In the adult, it measures about 7.5 cm in length, 5 cm wide at its upper part, and nearly 2.5 cm in thickness. It weighs ...
Short rib polydactyly syndrome(s) (SRPS) comprise a rare group of severe osteochondrodysplasias. There are four major recognised types present:
type I: Saldino-Noonan type
type II:: Majewski type
type III: Verma-Naumoff type
type IV: Beemer-Langer type
There may also be other very rare type...
Asymmetrical intrauterine growth restriction is a type of intrauterine growth restriction (IUGR) where some fetal biometric parameters are disproportionately lower than others, as well as falling under the 10th percentile. The parameter classically affected is the abdominal circumference (AC).
The cervix or uterine cervix is the lower constricted segment of the uterus providing the passage between the uterus proper and the vagina.
The cervix is somewhat conical in shape, with its truncated apex directed posteriorly and inferiorly. The inferior aspect of the cervix pro...
Fetal hydronephrosis represents the abnormal dilatation of the fetal renal collecting system, with pelviureteric junction obstruction the most commonly encountered cause.
Please, refer to the article on fetal pyelectasis for a dedicated discussion on this relatively common and usually benign f...
Fetal macrosomia (also sometimes termed large for gestational age) is usually defined when the estimated fetal weight (EFW) is greater than the 90th percentile. According to this definition, it affects up to 10% of all live births. Some also use an increased birthweight (i.e. greater than 4500g)...
Staging of cervical cancer can either be based on the TNM or FIGO system.
Revised FIGO staging of cervical carcinoma 2009 8
stage 0: cervical intraepithelial neoplasia (HSIL or CIN III)
stage I: confined to cervix
stage Ia: invasive carcinoma only diagnosed by microscopy.
Ia1: stromal inva...
Nuchal cord is a term given to the situation where there are one or more loops of umbilical cord wrapped around the fetal neck for ≥360°.
The prevalence is dependent on the extent of coiling and range from ~25% for a single loop to 2.5% for a double loop to ~0.5% for more than two...
Congenital cervical teratoma refers to a teratoma arising in the cervical region. They are thought to account for ~3% of teratomas in childhood/infancy 3.
The estimated occurrence in neonates is ~1:20,000-40,000 live births 8.
Most tumours are diagnosed at ...
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 radiog...
The vagina is a midline fibromuscular tubular structure positioned in the female perineum extending superiorly to the cervix and uterus in the pelvis.
The vagina is 8-10 cm in length, extending posterosuperior from the vestibule through the urogenital diaphragm to the uterus. Th...
Posterior urethral valves (PUVs), also referred as congenital obstructing posterior urethral membranes (COPUM), are the most common congenital obstructive lesion of the urethra and a common cause of obstructive uropathy in infancy.
Posterior urethral valves are congenital and only...
Fetus-in-fetu (FIF) is an extremely rare abnormality that occurs secondary to abnormal embryogenesis in a monochorionic diamniotic pregnancy where a non-viable fetus becomes enclosed within a normally developing fetus.
This condition is thought to have a 2:1 male predominance 2.
Brachycephaly refers to a calvarial shape where the bi-parietal diameter to fronto-occipital diameter approaches the 95th percentile. It can result from a craniosynostosis involving the coronal and lambdoid sutures.
Brachycephaly can be associated with numerous syndrom...
Polyhydramnios refers to a situation where the amniotic fluid volume is more than expected for gestational age.
It is generally defined as:
amniotic fluid index (AFI) >25 cm
largest fluid pocket depth (maximal vertical pocket (MVP)) greater than 8 cm 6: although some centres particularly in A...
Placenta praevia is a term given to an abnormally low position of the placenta such that it lies close to, or covers the internal cervical os.
It is a potentially life-threatening condition to both mother and infant, which may result in exsanguination. As such, antenatal diagnosis is essential...
Stenosis of the uterine cervix is the pathologic narrowing of the uterine cervix. The term cervical stenosis is clinically defined as cervical narrowing that prevents the insertion of a 2.5 mm wide dilator.
One-fifth of patients have a history of exposure to diethylstilbestrol whi...
Mesoblastic nephroma, also sometimes known as a congenital mesoblastic nephroma (CMN) or fetal renal hamartoma, is, in general, a benign renal tumour that typically occurs in utero or in infancy.
It is the commonest neonatal renal tumour. Diagnosis is usually made in the antenatal...
The twin peak sign (also known as the lambda (λ) sign) is a triangular appearance of the chorion insinuating between the layers of the inter twin 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 t...
Chiari II malformation, also known as Arnold-Chiari malformation, is a relatively common congenital malformation of the spine and posterior fossa characterised by myelomeningocoele (lumbosacral spina bifida aperta) and a small posterior fossa with a descent of the brainstem and cerebellar tonsil...
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...
Nuchal translucency is a finding during a specific period in the late first trimester and early second trimester (11.3-13.6 weeks) and should not be confused with the nuchal thickness, which is measured in the second trimester.
Increased nuchal translucency is thought to be related...
SHORT syndrome refers to an acronym which primarily comprises of the following features:
S: short stature
H: hyperextensibility of joints and/or inguinal hernia
O: ocular depression
R: Rieger anomaly
T: teething delay
In a addition to these there can be numerous associated minor features w...
Ileal atresia is a congenital abnormality where there is significant stenosis or complete absence of a portion of the ileum. There is an increased incidence in those with chromosomal abnormalities.
This article will focus on ileal atresia alone but bear in mind that some cases correspond to jej...
Frontonasal dysplasia, also known as median cleft face syndrome, is a rare disorder characterised by midline defects involving the face, head, and central nervous system.
Frontonasal dysplasia is considered to be a very rare condition, with approximately 100 cases having been repo...
Hypoplasia of the nasal bone refers to a sonographic observation where the fetal nasal bone appears smaller by varying degrees.
There is a spectrum of nasal bone hypoplasia, at one end of which is the relatively easily identified absent nasal bone. The other end of the spectrum is considerably ...
Barth syndrome (BTHS), also referred to as 3-methylglutaconic aciduria type II is an extremely rare X-linked multi-system disorder that is usually diagnosed in infancy.
It is characterised by:
fetal cardiomyopathy: (dilated fetal cardiomyopathy (DCM) +/- endocardial fibroelastosis (EFE) +/- le...
Endometrial reflectivity grading on ultrasound is a system initially proposed by Smith et al. in 1984 which classifies the endometrium into four types according to the echotexture pattern. They are considered to be useful in deciding on receptivity in in-vitro fertilisation (IVF).
The Smith sys...
Fetal biophysical profile score (BPS or BPP) refers to assessment of four discrete biophysical variables by ultrasound. It is a standard tool in antepartum fetal assessment. It is usually assessed after 28 weeks of gestation.
The ultrasound variables...
Preconception and prenatal diagnostic techniques (prohibition of sex selection) act (PCPNDT) is a statute enacted to stop the female foeticide that has resulted in declining female sex ratio in India.
As per census 2011, adult sex ratio in India is 943 females per 1000 males and child sex ratio...
Brachydactyly (BD) essentially refers to short digits. It is often inherited as an autosomal dominant trait (all the types). The clinical spectrum can widely range from minor digital hypoplasia to complete aplasia. As a group, it most commonly involves the middle phalanx 2.
Single or multiple b...
HELLP syndrome is a pregnancy-related condition and is an abbreviation for:
elevated liver enzymes and
It is considered a severe and life-threatening form of pre-eclampsia although it can occur without co-existing pre-eclampsia.
The estimated inciden...
NB - Please consult original article(s) and discuss with you local radiology department/radiation physicist before making any clinical decision.
Although exposure to the gravid uterus is to be avoided when ever possible, and only deliberately performed after careful weighing up of the pros and ...
Twin to twin transfusion syndrome (TTTS) is a potential complication that can occur in a monochorionic twin (either MCDA or MCMA) pregnancy.
This complication can occur in ~10% (range 15-25%) of monochorionic pregnancies giving an estimated prevalence of ~1:2000 of all pregnancie...
Acute fatty liver of pregnancy (AFLP) is a rare pregnancy-associated condition that tends to manifest in the 3rd trimester of pregnancy or early postpartum period.
The estimated incidence is at around 1:7000-20,000 births.
Patients may present with nausea,...
Vein of Galen aneurysmal malformations (VGAMs), probably better termed as median prosencephalic arteriovenous fistulas, are uncommon intracranial anomalies that tend to present dramatically during early childhood with features of a left-to-right shunt and high-output cardiac failure.
Pulmonary hypoplasia (PH) refers to deficient or incomplete development of parts of the lung. It can develop as a result of a number of other in-utero anomalies.
The true prevalence is not well known (1.4% of all births according to Knox et.al 13), but in cases of premature ruptur...
Ovarian hyperstimulation syndrome (OHSS) is a complication of ovarian stimulation treatment (ovarian induction therapy) for in vitro fertilisation. Rarely, it may also occur as a spontaneous event in pregnancy (see spontaneous ovarian hyperstimulation later in the article).
The clinical syndrom...
A sandal gap deformity, also known as hallux varus, is an imaging observation in antenatal ultrasound (typically second trimester) where there is an expanded first interspace, i.e. the gap between the great toe of the foot from the rest of the toes (likened to the gap caused by a sandal).
Diastrophic dysplasia (DTD) is a type of short limb skeletal dysplasia (micromelic dwarfism). Adult patients have a stature between 100 and 140 cm.
There may be a relatively increased prevalence in Finland ref.
Typically there is limb shortening, hitchhiker thu...
Ventricular septal defects (VSD) represent defects in the interventricular septum that allow a haemodynamic communication between the right and left ventricles. It typically results in a left-to-right shunt.
They represent one of the most common congenital cardiac anomalies and ma...
A succenturiate lobe is a variation in placental morphology and refers to a smaller accessory placental lobe that is separate to the main disc of the placenta. There can be more than one succenturiate lobe.
The estimated incidence is ~2 per 1000 pregnancies.
Ectopic pregnancy refers to the implantation of a fertilised ovum outside of the uterine cavity.
The overall incidence has increased over the last few decades and is currently thought to affect 1-2% of pregnancies. The risk is as high as 18% for first trimester pregnancies with bl...
Radiological evaluation of the posterior fossa is an essential part of the routine fetal assessment, including vermian maturity assessment.
Ultrasonography is a readily available diagnostic tool in the assessment of the fetal posterior fossa but is sometimes limited due t...
Umbilical venous flow in the physiological situation comprises of a monophasic non-pulsatile flow pattern with a mean velocity of 10-15 cm/s. The presence of pulsatility implies a pathological state unless in the following situations:
early in pregnancy: up to ~13 weeks gestation
Evaluation of vermian lobulation is essential in assessment of the vermian maturity. MRI is a useful tool in assessment of the fetal posterior fossa.
Normal Vermian lobulation by weeks 1:
By 21 weeks - Prepyramidal fissure can be seen between the tuber and pyramis.
21 to 22 weeks - Preculmina...
Macroglossia means an enlarged tongue. It may be absolute (greater than the 95th centile) or relative (enlarged compared with oral cavity).
Recognised associations include:
tends to be a relative macroglossia
may also have intermi...
Robinow syndrome is a rare heterogenous genetic disorder with at least two distinct forms.
The syndrome can affects several systems which include:
mesomelic limb shortening: mesomelia
characteristic facies anomalies
The left ventricular outflow tract (LVOT) view (or five chamber view) is one of the standard views in a fetal echocardiogram.
It is a long axis view of the heart, highlighting the path from the left ventricle into the ascending aorta (left ventricle outflow tract).
In this view the right ventr...
Ectopia cordis is an extremely rare congenital malformation where the heart is located partially or totally outside the thoracic cavity. The four main ectopic positions are::
adjacent to the thorax: ~60 %
The estimated ...
Fetal pericardial effusions (FPE) occur when there is an accumulation of pericardial fluid in utero. In order to be considered as abnormal, it is generally accepted that the pericardial fluid thickness should be greater than 2 mm.
The estimated incidence is at ~ 2% of pregnancies ...
Hanging noose sign in obstretric 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 movemen...
The rhombencephalon, or hindbrain is a primary vesicle of the neural tube.
During the fifth week of embryological development the rhombencephalon further subdivides into the secondary brain vesicles, the metencephalon and the myelencephalon 1.
The metencephalon goes on to form th...
Placental mesenchymal dysplasia (PMD) is a rare, benign condition that is characterised by enlargement of the placenta with multiple bunch of grape-like vesicles that can resemble a molar pregnancy by ultrasound and gross pathologic examination.
This is an often underdiagnosed an...
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.
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.
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.
Birth trauma relates to those conditions caused by both physical/mechanical and hypoxic injuries.
Birth trauma occurs in ~5 per 1000 births 2.
Hypotelorism refers to an abnormal decrease in distance between any two organs although some authors use the term synonymously with orbital hypotelorism meaning an abnormal decrease in the distance between the two eyes (the eyes appear too close together). The article mainly focuses on the latte...
Frontal bossing is a calvarial radiographic feature where the front of the skull appears protruding anteriorly. It is best appreciated on a sagittal or lateral image.
This feature can be seen in many conditions (in alphabetical order):
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...
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...
Bladder exstrophy (also known as ectopia vesicae) refers to a herniation of the urinary bladder through an anterior abdominal wall defect. The severity of these defects is widely variable.
The estimated incidence of bladder exstrophy is 1:10,000-50,000 live births 4,6. There is a ...
The limb-body wall complex (LBWC) is a rare variable group of congenital limb and body wall defects (involving mainly the chest and abdomen). They can include:
abdominoschisis: usually large and left-sided 4, and almost always present
thoracic wall defect / thoracoschisis
Pregnancy of uncertain viability (PUV) is a term given to an intrauterine pregnancy in a situation where there are not enough criteria (usually on ultrasound grounds) to confidently categorise an intrauterine pregnancy as either viable or a failed pregnancy.
A small placenta if observed on antenatal ultrasound can arise from a number of situations. They include:
variation in placental morphology: where only part of the placenta is seen
bilobed placenta: with only one lobe seen
succenturiate lobe: with either main lobe or succenturiate lobe not se...
Oligohydramnios refers to a situation where the amniotic fluid volume is less than expected for gestational age. Often these fetuses have <500 mL of amniotic fluid.
The estimated prevalence can be up to ~6% of pregnancies 4.
The causes of oligohydramnios are pr...
The lying down adrenal sign is a feature seen usually associated with renal agenesis or renal ectopia. It is an important antenatal sonographic sign.
On an antenatal ultrasound scan, the adrenal of the affected side appears flattened, elongated, and lying along the spine due to absence of the ...
Fetal rib fractures can be caused by certain skeletal dysplasias. These include:
osteogenesis imperfecta: type II - one of the classical causes of fetal rib fractures
achondrogenesis: type Ia - Houston-Harris sub type
Fetal pleural effusions (FPE) refer to an accumulation of pleural fluid in utero. It can refer to either a fetal chylothorax or a fetal hydrothorax.
A fetal pleural effusion can occur as part of hydrops fetalis, in association with other anomalies without hydrops or in isolation - pr...
Fetal clenched hands are an antenatal ultrasound observation where the fetal hands are in a constant (permanently) clenched position as if being unable to extend.
Some authors 3 suggest that the abnormal posture results in part from:
muscle variations along the radial margin of the...
Fetal chylothorax is defined as the presence of lymphatic fluid within the pleural cavity.
may show echogenic fluid in the pleural cavities
Some of the de...
Fetal cardiac tumours refer to primary cardiac tumours that can present in the in utero population.
Fetal cardiac tumours are rare; the prevalence, reported from autopsy studies of patients of all ages, varies from 0.0017-0.28 % 2.
Known cardiac tumour types that pres...
Fetal ascites refers to the accumulation of free fluid in the fetal abdomen. It is often considered under the same spectrum of hydrops fetalis.
any condition that results in hydrops fetalis
additional causes include
bowel perforation (e.g. meconium peritoniti...
Failed early pregnancy refers to the death of the embryo and therefore, miscarriage. The most common cause of embryonic death is a chromosomal abnormality.
Findings diagnostic of pregnancy failure
crown-rump length (CRL) of ≥7 mm and no heartbeat on a transva...
Congenital renal anomalies comprise of vast spectrum of pathologies and include:
congenital renal hypoplasia
congenital cystic renal disease
infantile polycystic renal disease: autosomal recessive polycystic kidney disease (ARPKD):...
Non-visualisation of the fetal stomach on ultrasound can occur with various physiological as well as pathological processes. It becomes a significant sonographic observation >14 weeks of gestation (about the time the fetus begins to swallow).
physiological emptying: transient
Syndactyly refers to a congenital fusion of two or more digits. It may be confined to soft tissue (soft tissue syndactyly / simple syndactyly) or may involve bone (bony syndactyly / complex syndactyly).
The overall estimated incidence is at ~1 per 2500 to 5000 live births 6,8. The...
Obstetric and gynaecological ultrasound is rampant with numerous cut off values. Some of these get revised over the years. The following list is a useful aid to refer to and revise.
rate of increase of a mean sac diameter per day in early pregnancy
generally accepted value for a th...
A large for date uterus is a clinical observation based on uterine fundal height, which may result in referral for ultrasound assessment, usually in mid to late pregnancy.
constitutionally large fetus
IUCD related uterine perforations are one of the causes of uterine perforation. It is rare, but a serious complication of an IUCD insertion, and is often clinically silent.
The incidence rate is reported at ~2 in 1000 2.
Perforation at the time of insertio...
Intra-uterine contraceptive devices (IUCD) are one of the most frequently used methods of contraception throughout the world. It prevents pregnancy by:
thinnning the endometrial lining
preventing sperm motility
There are two main types of IUCDs:
Endometrial thickness is a commonly measured parameter on routine gynaecological ultrasound and MR imaging. The appearance, as well as the thickness of the endometrium, will depend on whether the patient is of reproductive age or post-menopausal and, if of reproductive age, at what point in the ...
Cystic hygroma, also known as cystic or nuchal lymphangioma, refers to the cystic variety of congenital lymphangioma which, most commonly, occur in the cervicofacial regions, particularly at the posterior cervical triangle.
They usually occur in the fetal/infantile and paediatri...
Fetal intracranial cystic lesions can arise number of pathologies, including:
fetal arachnoid cyst
fetal choroid plexus cyst
fetal connatal cyst
fetal porencephalic cyst
fetal interhemispheric cyst
fetal sub ependymal cyst
dorsal cyst of holoprosencephaly
Blake pouch cyst...
The amniotic fluid index (AFI) is an estimate of the amniotic fluid volume in a fetus. It is part of the fetal biophysical profile.
uterus is divided into four imaginary quadrants with linea nigra and umbilicus acting as the vertical and the horizontal axis respectively
Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) (also known as the Berdon syndrome) is a rare congenital disorder characterised by a dilated non-obstructive urinary bladder and hypoperistalsis of the gastrointestinal tract.
There is recognised strong female predi...
Placental evaluation with MRI is a problem-solving technique that can be used if ultrasound evaluation is insufficient or confusing. Even if the placenta is not the main point of evaluation, it is useful to understand the appearance of the placenta on obstetric imaging for other causes.
Uterine dehiscence is, usually, used to refer to the process of gradual myometrial rupture without a rupture of membranes. However, the term is used synonymously with uterine rupture by some authors. It is often described in the context of C-section scar where it is also termed an incisional deh...
Retained products of conception (RPOC) refer to the persistence of placental and/or fetal tissue in the uterus following delivery, termination of pregnancy or a miscarriage.
Retained products of conception complicate ~1-5% of all pregnancies (routine vaginal deliveries 12).
Cystic hygroma and occipital meningocele are both differential diagnosis for an antenatally detected cystic collection noted on the posterior aspect of the head and neck.
A simple differentiation can be made based on the contents and presence of septations:
cystic hygroma will present as a wel...
Omphalocoeles, or exomphalos, are congenital midline abdominal wall defects at the base of the umbilical cord insertion with herniation of gut (or occasionally other content) out of the fetal abdomen.
The estimated occurrence can be up to 1:4000 of live births 3.