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Camptodactyly

Camptodactyly is a clinical or imaging descriptive term where there is a flexion contracture (usually congenital). Classically this occurs at the proximal interphalangeal joint of the little finger of the hand, although any finger may be affected. Epidemiology Prevalence ~1%; one-third unilate...

Camptodactyly arthropathy coxa vara pericarditis syndrome

Camptodactyly arthropathy coxa vara pericarditis (CACP) syndrome is a rare condition principally characterized by congenital or early-onset camptodactyly and childhood-onset non-inflammatory arthropathy coxa vara deformity or other dysplasia associated with progressive hip disease pericardit...

Cardiac rhabdomyoma

Cardiac rhabdomyomas are a type of benign myocardial tumor and are considered the most common fetal cardiac tumor. They have a strong association with tuberous sclerosis. Epidemiology Cardiac rhabdomyomas are often multiple and can represent up to 90% of cardiac tumors in the pediatric populat...

Carpenter syndrome

Carpenter syndrome, also called acrocephalopolysyndactyly type II (ACPS type II) is an extremely rare autosomal recessive congenital disorder Clinical spectrum It is characterized by number of features which include: craniofacial malformations craniosynostoses kleeblattschädel (cloverleaf ...

Causes of oligohydramnios (mnemonic)

A helpful mnemonic for remembering some causes of oligohydramnios is: DRIPPC Mnemonic D: demise R: renal abnormalities (decreased urine output) I: IUGR P: premature rupture of membranes P: post-dates C: chromosomal anomalies

Cebocephaly

Cebocephaly refers to a type of rare midline craniofacial anomaly where there is a single nostril (which usually ends blindly 6-7) with proboscis-like nose 8 and hypotelorism. Pathology Associations holoprosencephaly: particularly alobar holoprosencephaly trisomy 13 See also ethmocephaly ...

Cenani-Lenz syndactyly

Cenani-Lenz syndactyly (CLS) is a very syndrome primarily characterized by: syndactyly/oligodactly: syndactyly is often complete and gives a spoon hand type appearance radio-ulnar synostoses Pathology Genetics It carries an autosomal recessive inheritance. Etymology It was first described...

Cephalic index

The cephalic index (CI) is a value calculated using two fetal biometric parameters which are the occipitofrontal diameter (OFD) and the biparietal diameter (BPD). It is calculated as: cephalic index (CI) = biparietal diameter (BPD)/occipitofrontal diameter (OFD) x 100 The cephalic index gi...

Cephalocele

Cephalocele refers to the outward herniation of CNS contents through a defect in the cranium. The vast majority are midline. Epidemiology The estimated incidence is 0.8-4:10,000 live births 13 with a well recognised geographical variation between types; however, this has been speculated to be ...

Cephalohaematoma

Cephalohaematomas are traumatic subperiosteal hematomas of the skull that are usually caused by birth injury. They are bound between the periosteum and cranium, and therefore cannot cross sutures. Being bound by a suture line distinguishes them from subgaleal hematoma, which can cross sutures. ...

Cephalopagus

Cephalopagus twins are a rare type of conjoined twins. They are fused from the vertex to the umbilicus. They share a common cranium with either one composite face or two faces on opposite sides of the conjoined head. The thoraces are fused with fusion of liver, heart and the upper gastrointesti...

Cephalopelvic disproportion

Cephalopelvic disproportion (CPD) occurs when there is a mismatch between the size of the fetal head and the maternal pelvis causing a difficulty in the safe passage of the fetus through the birth canal. Pathology Cephalopelvic disproportion may be caused by the fetal head outgrowing the capac...

Cerebroplacental ratio

Cerebroplacental ratio (CPR) is an obstetric ultrasound tool used as a predictor of adverse pregnancy outcome in both small for gestational age (SGA) and appropriate for gestational age (AGA) fetuses. An abnormal CPR reflects redistribution of cardiac output to the cerebral circulation, and has ...

Cervical cancer (staging)

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...

Cervical ectopic pregnancy

Cervical ectopic pregnancy is a rare subtype of ectopic pregnancy. Epidemiology It accounts for ~0.15-1% of all ectopic pregnancies. Pathology Implantation of the fertilized ovum occurs within the cervix rather than the uterine cavity. Unless the fetal heart rate can be identified, it is di...

Cervical incompetence

Cervical incompetence refers to a painless spontaneous dilatation of the cervix and is a common cause of second trimester pregnancy failure. Epidemiology The estimated incidence varies geographically and generally thought to be around 1-1.5% of all pregnancies 1,15. Clinical presentation Typ...

Cervical incompetence morphological changes on ultrasound (mnemonic)

Sequential morphological ultrasound changes of the endocervical canal with cervical incompetence can be remembered using the mnemonic: Trust Your Vaginal Ultrasound Mnemonic T-shaped (normal internal cervical os) Y-shaped V-shaped U-shaped Related article cervical incompetence funnelin...

Cervical length

In obstetric and gynecological imaging, the cervical length is defined as the distance between the internal cervical os and the external cervical os. Radiographic assessment Ultrasound the cervical length is most accurately assessed on a transvaginal scan with an empty bladder in a normal gr...

Cervical stenosis (disambiguation)

The term cervical stenosis can refer to: stenosis of the uterine cervix bony cervical canal stenosis (cervical spinal stenosis)

Cervix

The cervix or uterine cervix is the lower constricted segment of the uterus providing the passage between the uterus proper and the vagina. Gross anatomy The cervix is somewhat conical in shape, with its truncated apex directed posteriorly and inferiorly. The inferior aspect of the cervix pro...

Cesarean scar niche

The term Cesarean scar niche (defect) refers to the presence of a hypoechoic area within the myometrium in the isthmus (lower uterine segment) with discontinuation of myometrium at the site of previous Cesarean section scar. A niche has been described as the indentation of myometrium of around 1...

Chiari III malformation

Chiari III malformation is an extremely rare anomaly characterized by a low occipital and high cervical encephalocele with herniation of posterior fossa contents, that is, the cerebellum and/or the brainstem, occipital lobe, and fourth ventricle. Pathology Associations agenesis of the corpus...

Chiari II malformation

Chiari II malformation, also known as Arnold-Chiari malformation, is a relatively common congenital malformation of the spine and posterior fossa characterized by myelomeningocele (lumbosacral spina bifida aperta) and a small posterior fossa with descended brainstem and cerebellar tonsils. Numer...

CHILD syndrome

CHILD (congenital hemidysplasia with ichthyosiform erythroderma and limb defects) syndrome comprises: Ch: congenital hemidysplasia I: ichthyosiform erythroderma develops at or shortly after birth unilateral erythema and scaling, with a distinct demarcation in the middle of the trunk 2 hair ...

Chondrodysplasia punctata

Chondrodysplasia punctata (CDP) is a collective name for a heterogenous group of skeletal dysplasias. Calcific stippling of cartilage and peri-articular soft tissues is often a common feature. Pathology Subtypes It can be broadly divided into rhizomelic and non-rhizomelic forms: rhizomelic c...

Chondroectodermal dysplasia

Chondroectodermal dysplasia, also known as the Ellis-van Creveld syndrome, is a rare type of skeletal dysplasia. It is classified as a type of mesomelic limb shortening 5. Clinical spectrum Clinical features include: narrowing of thorax with short ribs small and flared ilia triradiate aceta...

Chorioamnionitis

Chorioamnionitis refers to infection of the chorion and amnion during pregnancy. Epidemiology Chorioamnionitis affects an estimated 2-4% of term deliveries and 40-70% of preterm deliveries1. Clinical presentation Clinically, chorionamnionitis can present with the following maternal signs and...

Chorioamniotic separation

Chorioamniotic separation (CAS) is an intra-uterine event which can occur in pregnancy and is characterized by separation of placental (chorion) and fetal (amnion) membranes. Pathology The membranes are separated in early gestation, accounting for the appearance of the amniotic sac. After appr...

Choriocarcinoma

Choriocarcinoma is an aggressive, highly vascular tumor. When it is associated with gestation, it is often considered part of the spectrum of gestational trophoblastic disease; it is then termed gestational choriocarcinoma. When it occurs in the absence of preceding gestation, it is termed non-g...

Choriocarcinoma (staging)

The staging system for choriocarcinoma (usually refers to uterine choriocarcinoma) is the FIGO staging system and is as follows 1: stage I: disease limited to the uterus stage II: disease out of the uterus but limited to the female genital tract stage III: metastasis in the lung with or with...

Chorion

The chorion is one of the embryonic membranous structures than encloses both the fetus as well as the amnion. The chorion begins to form chorionic villi towards its outer surface, which initially serves to provide nutrition to the developing embryo. Part of the chorionic villi arborize more ex...

Chorionic bump

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. Epidemiolo...

Chorionic plate

The chorionic plate is a synonym for the fetal side of the placenta. The maternal side of the placenta is termed the basal plate. Some pathologies and processes are localized to the chorionic plate, and evaluation of the chorionic plate is a part of placental grading.

Chorionic villus sampling

Chorionic villus sampling (CVS) is an antenatal procedure for prenatal diagnosis of chromosomal or genetic disorders in the fetus. It entails getting a sample of the chorionic villus (placental tissue) and testing it. A transabdominal or transcervical approach is selected depending on the posit...

Choroid plexus cyst (antenatal)

Antenatal choroid plexus cysts are benign and are often transient typically resulting in utero from an infolding of the neuroepithelium. They should not be confused with adult choroid plexus cysts (which are very commonly found at autopsy and likely degenerative), large intraventricular simpl...

Chromosomal anomalies

There are large number of recognised chromosomal anomalies (many with eponymous names). When there is a change in the absolute number of chromosomes these are sub grouped as aneuploidic anomalies. They can cause variable handicap - outcome ranging from some having no effect (in some balanced tr...

Circummarginate placenta

Circummarginate placenta is an uncommon variation in placental morphology. The chorionic membranes insert inward from the margin of placental edge, similar to circumvallate placenta, but unlike circumvallate placenta, the placental edge is not thickened and rolled up, and there is no central d...

Circumvallate placenta

Circumvallate placenta refers to a variation in placental morphology in which, as a result of a small chorionic plate, the amnion and chorion fetal membranes ‘double back’ around the edge of the placenta. Epidemiology The prevalence is estimated to be around 1-7% 3. Pathology There is an inw...

Cleft lip and palate

Cleft lip and palate is one of the commonest of neonatal facial anomalies. In ~80% of cases, the two features tend to occur together 6. Epidemiology It is estimated to occur with an incidence of ~1 in 700-to-1000 live births 1. This can increase to 4% for a sibling of a previously affected fet...

Clinodactyly

Clinodactyly is a descriptive term that refers to a radial angulation at an interphalangeal joint in the radio-ulnar or palmar planes. It typically affects the 5th finger. Epidemiology The estimated incidence is highly variable dependent on sampling and has been reported to range between 1-18...

Cloacal exstrophy

Cloacal exstrophy (CE) is an extensive congenital abdominal wall defect which encompasses: exstrophy of the bladder omphalocele lower abdominal wall defect Epidemiology The estimated prevalence is at around 1 in 50,000 to 200,000 live births. There is a recognised male predilection with a M...

Cloverleaf skull

Cloverleaf skull, also known as kleeblattschädel, 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, coronal and lambdoid suture...

Cockade sign (disambiguation)

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

Coexistent molar pregnancy

Coexistent molar pregnancy refers to an extremely rare situation where there is a molar pregnancy occurring simultaneously with normal intra-uterine pregnancy. Epidemiology The estimated incidence is at ~1:10,000-100,000 gestations (for a complete hydatidiform mole and a normal pregnancy) 2. ...

Coffin-Lowry syndrome

Coffin-Lowry syndrome (CLS) is a rare X-linked genetic syndrome affecting multiple body parts. Epidemiology The condition tends to affect males much more due to its X-linked inheritance. The estimated incidence is at around 1:40,000-50,000. Clinical presentation It is characterized by a numb...

Complete hydatidiform mole

Complete hydatidiform mole (CHM) is a type of molar pregnancy and falls at the benign end of the spectrum of gestational trophoblastic disease. Epidemiology CHM is the commonest type of gestational trophoblastic disease. Pathology Complete moles are characterized by the absence of a fetus o...

Complete hydatidiform mole with coexistent fetus

Complete hydatidiform mole with coexistent fetus (CHMCF) is an extremely rare entity whereas the name suggests there is a twin pregnancy with a complete hydatidiform mole and a normal fetus. Epidemiology It is seen extremely rarely, with an estimated incidence of one in 22,000–100,000 pregnan...

Complete miscarriage

A complete miscarriage is defined as a cessation of vaginal bleeding with no evidence of retained products of conception or a gestation sac in a woman who previously had an ultrasound confirmed intrauterine pregnancy. Radiographic features Ultrasound Shows an empty uterus with no fetal compon...

Complete placenta praevia

A complete placenta praevia, also known as a type IV placenta praevia, is the most severe in terms of the placenta praevia spectrum. It is also the least likely to resolve with advancing gestation if detected in early pregnancy 1,3. Pathology In this situation, the placenta entirely covers the...

Congenital cervical teratoma

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. Epidemiology The estimated occurrence in neonates is ~1:20,000-40,000 live births 8. Clinical presentation Most tumors are diagnosed at b...

Congenital cytomegalovirus infection

Congenital cytomegalovirus infection results from intra-uterine fetal infection by cytomegalovirus (CMV). Epidemiology CMV is the most common cause of intra-uterine infection and most common cause of congenital infective and brain damage, occurring in 0.2-2.4% of live births. Antibodies to ...

Congenital goiter

Congenital goiter is a rare cause of neck swelling in neonates and is demonstrated as diffuse/nodular thyroid gland enlargement. Epidemiology It is a common endocrine disease in newborns and affects approximately 1:2000-4000 live births. Clinical presentation There may be a difficult vaginal...

Congenital granular cell myoblastoma

A congenital granular cell myoblastoma (also known as congenital epulis) is a very rare benign tumor which classically presents in the fetal-neonatal population. Epidemiology It occurs almost exclusively in females when it presents in the fetal-neonatal population although no such predilection...

Congenital high airways obstruction syndrome

Congenital high airways obstruction syndrome (CHAOS) refers to a rare, often lethal, congenital laryngotracheal condition and is primarily characterized by obstruction to the fetal upper airway. Pathology CHAOS can be of three possible types 2: complete laryngeal atresia without an esophageal...

Congenital hypothyroidism

Congenital hypothyroidism (CHT), previously known as cretinism, can be of thyroidal or central (hypothalamic/pituitary) origin and can have a widely diverse molecular etiology. Clinical presentation Most children are asymptomatic at birth and are diagnosed after screening. In untreated CHT pat...

Congenital infections (mnemonic)

The group of the most common congenital infections are referred to by the mnemonic TORCH or STORCH. They usually cause mild maternal morbidity, but are related to serious fetal consequences 4. Mnemonic T: toxoplasmosis O: other (e.g. syphilis, varicella-zoster, parvovirus B19) R: rubella C:...

Congenital limb amputation

Congenital limb amputation is the absence of a fetal limb or part of a limb that usually occurs due to disruption of vascular supply. Epidemiology Congenital amputations occur in 0.5 (range 0.03-1) per 1000 live births 2. Pathology They are slightly more common in the upper limb (60%) than ...

Congenital megaureter

A congenital (primary) megaureter encompasses causes of an enlarged ureter which are intrinsic to the ureter, rather than as a result of a more distal abnormality; e.g. bladder, urethra (see secondary megaureter). It includes: obstructed primary megaureter refluxing primary megaureter althoug...

Congenital pulmonary airway malformation

Congenital pulmonary airway malformations (CPAM) are multicystic masses of segmental lung tissue with abnormal bronchial proliferation. CPAMs are considered part of the spectrum of bronchopulmonary foregut malformations. Terminology Until recently they were described as congenital cystic adeno...

Congenital renal anomalies

Congenital renal anomalies comprise of vast spectrum of pathologies and include: renal agenesis renal dysgenesis congenital renal hypoplasia congenital megacalyectasis congenital cystic renal disease infantile polycystic renal disease: autosomal recessive polycystic kidney disease (ARPKD):...

Congenital talipes equinovarus

Congenital talipes equinovarus (CTEV) is considered the most common anomaly affecting the feet diagnosed on antenatal ultrasound. Terminology While some use CTEV and clubfoot (CF) synonymously, in certain publications term clubfoot is considered a more general descriptive term that describes t...

Congenital utero-vaginal anomalies

There are many classification systems for congenital utero-vaginal anomalies. These include: Buttram and Gibbons classification 2 American Fertility Society (AFS) classification Modified Rock and Adam - AFS classification Modified Rock and Adam - AFS classification This classification divid...

Conjoined twins

Conjoined twin pregnancy is a rare occurrence resulting from the failure of a zygote to separate completely after 13 days. This results in the twins being physically joined. Epidemiology The prevalence of conjoined twins ranges from 1:50,000 to 1:200,000. They are more common in parts of South...

Conotruncal cardiac anomalies

Conotruncal heart defects are a group of congenital cardiovascular anomalies. They are a leading cause symptomatic cyanotic cardiac disease diagnosed in utero. Epidemiology They may account for up to a fifth of all congenital cardiac anomalies diagnosed prenatally 2. Clinical presentation Du...

Cordocentesis

Cordocentesis is a method of fetal blood sampling which is usually carried out under ultrasound guidance. Indications It may be performed for various reasons which include: establish the degree of a fetal anemia further investigation of an underlying chromosomal anomaly further investigatio...

Cord presentation

A cord presentation (also known as a funic presentation) is a variation in the fetal presentation where the umbilical cord points towards the internal cervical os or lower uterine segment. It may be a transient phenomenon and usually considered insignificant until ~32 weeks. It is concerning if...

Cornelia de Lange syndrome

Cornelia de Lange syndrome (CdLS) is an extremely rare clinically heterogenous developmental disorder of unknown etiology. Epidemiology The estimated incidence is at ~1:10,000-160,000 births ref. There is no recognised racial or gender predilection 8. Clinical presentation The syndrome carri...

Corpus luteal cyst rupture

Ruptured corpus luteal cysts are one of the commonest causes of spontaneous hemoperitoneum in a woman of reproductive age. Clinical presentation Presentation is variable, ranging from completely asymptomatic to severe abdominal pain due to peritoneal irritation. Pathology The corpus luteum i...

Corpus luteum

The corpus luteum is a temporary endocrine structure involved in ovulation and early pregnancy. During ovulation, the primary follicle forms the secondary follicle and subsequently the mature vesicular follicle. At ovulation the follicle ruptures expelling the ovum into the fallopian tube. The...

Craniopagus

Craniopagus twins are conjoined twins that are fused at any part of the skull, except the face, foramen magnum, skull base and the vertebral column. The fused structures are most often the cranium, meninges, and dural venous sinuses. Brains tend to be separate; however, may be connected by a br...

Craniorachischisis

Craniorachischisis, also known as craniorachischisis totalis, is a rare birth defect and the most severe of the neural tube defects. It refers to the presence of both anencephaly and spina bifida. Epidemiology In one study the prevalence of craniorachischisis was 0.51 per 10,000 live births in...

Crouzon syndrome

Crouzon syndrome is rare disorder characterized by premature craniosynostoses. Pathology Features include: abnormal calvarial shape: in severe case can give a "cloverleaf skull" shallow orbits with exopthalmos mid facial hypoplasia bifid uvula Genetics It carries an autosomal dominant ...

Crown rump length

Crown rump length (CRL) is the length of the embryo or fetus from the top of its head to bottom of torso. It is the most accurate estimation of gestational age in early pregnancy, because there is little biological variability at that time. Measurement CRL is measured as the largest dimension ...

Currarino syndrome

The Currarino syndrome is a complex condition variably comprised of characteristic congenital anomalies of the sacrum, anorectum and presacral soft tissues. It is also known as the Currarino triad or ASP triad, however, not all three features are always present 6. anorectal malformation or con...

Cyclopia

Cyclopia refers to a rare fetal malformation characterized by a single palpebral fissure and a single midline orbit. This orbit may contain either a single globe or two separate globe. Epidemiology The condition is thought to affect approximately 1 in 40,000 to 95,000 births (inclusive of stil...

Cystic hygroma

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. Epidemiology They usually occur in the fetal/infantile and pediatric...

Cystic hygroma vs occipital meningocele

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...

Cystic renal dysplasia

Cystic renal dysplasia refers to a subgroup of congenital anomalies of the kidney and urinary tract characterized by the dysplastic renal parenchyma and formation of cysts. The most severe form is multicystic dysplastic kidney, in which functional renal parenchyma is absent and only undifferenti...

Dandy-Walker variant

Dandy-Walker variant (DWv) is a less severe posterior fossa anomaly than the classic Dandy-Walker malformation (DWM) and is considered being on the lesser end of the disease spectrum in the Dandy-Walker continuum. Terminology This term was created to include those malformations that do not mee...

Decidual cast

Decidual cast refers to the presence of an amount of relatively echogenic material in the uterine cavity in the context of an ectopic pregnancy.

Decidual reaction

A decidual reaction is feature seen in very early pregnancy where there is a thickening of the endometrium around the gestational sac. A thin decidual reaction of less than 2 mm is considered one of the features suggestive of an anembryonic pregnancy 2. A decidual reaction in some situations can...

Deepest vertical pocket method

The deepest (maximal) vertical pocket (DVP) depth is considered a reliable method for assessing amniotic fluid volume on ultrasound 1,2. It is performed by assessing a pocket of a maximal depth of amniotic fluid which is free of an umbilical cord and fetal parts. The usually accepted values are...

Demise of a twin

Demise of a twin is a complication that can occur in a twin pregnancy (particularly monochorionic pregnancies) and may be due to a wide range of conditions. Once the twin dies, most of the dead twin tends to be absorbed leaving behind a small flattened remnant known as the fetus papyraceus. Epi...

Diabetic embryopathy

Diabetic embryopathy refers to a spectrum of fetal anomalies that precipitate when the mother has background type I diabetes. The fetus may develop many of the fetal conditions associated with maternal diabetes although strictly speaking the the anomalies should only include those that start in ...

Diastrophic dysplasia

Diastrophic dysplasia (DTD) is a type of short limb skeletal dysplasia (micromelic dwarfism). Adult patients have a stature between 100 and 140 cm. Epidemiology There may be a relatively increased prevalence in Finland ref. Clinical features Typically there is limb shortening, hitchhiker thu...

Dichorionic diamniotic twin pregnancy

A dichorionic diamniotic (DCDA) twin pregnancy is a type of twin pregnancy where each twin has its own chorionic and amniotic sacs. This type occurs most commonly with dizygotic twins, but may also occur with monozygotic twin pregnancies. This type of pregnancy may have characteristic findings o...

Dichorionic twin pregnancy

A dichorionic twin pregnancy is type of twin pregnancy characterized by two chorions. The are always dichorionic-diamniotic but can be be either monozygotic (~ 11%) or dizygotic ( ~ 88%).

Differential diagnosis for bleeding in pregnancy

Uterine bleeding during pregnancy is a common clinical presentation that often necessitates obstetric ultrasound for the assessment of the hemorrhage, and of fetal well being. The potential causes vary with the stage of gestation. Bleeding in the first trimester miscarriage threatened miscar...

Dizygotic twin pregnancy

A dizygotic (DZ) twin pregnancy is a type of twin pregnancy where two separate ova are independently fertilised by two separate sperm resulting the two separate zygotes. These twins are also known as fraternal twins or non-identical twins. They may or may not be of the same gender. Epidemiolog...

Dominant ovarian follicle

A dominant ovarian follicle refers to the follicle that enlarges to release an ovum during a menstural cycle. Usually approximately 10 Graafian follicles begin to mature where one becomes a dominant follicle and the rest become atretic ovarian follicles. After release of the ovum the remainder o...

Dorsal cyst of holoprosencephaly

The dorsal cyst of holoprosencephaly is a large cerebrospinal fluid cavity present in holoprosencephaly that occupies the area above the dorsocaudal aspect of the diencephalon. This communicates directly with the prosencephalic, telencephalic, or diencephalic ventricle. This cavity usually abuts...

Double bleb sign

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 appearence of two small bubbles 2. The embryonic disk is located between the two bubbles. It is an important feature of an intrauterine pregnancy and thu...

Double decidual sac sign

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...

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