Articles
Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and continuously improved upon by countless contributing members. Our dedicated editors oversee each edit for accuracy and style. Find out more about articles.
786 results found
Article
Chromosomal anomalies
There are a large number of recognized chromosomal anomalies (many with eponyms). When there is a change in the absolute number of chromosomes these are subgrouped as aneuploidic anomalies.
They can cause a variable degree of disability with outcomes ranging from no effect (in some balanced tra...
Article
Congenital high airway obstruction syndrome
Congenital high airway obstruction syndrome or sequence (CHAOS) refers to a rare, often lethal, congenital laryngotracheal condition and is primarily characterized by obstruction to the fetal upper airway.
Epidemiology
Associations
Fraser syndrome
Pathology
CHAOS can be of three possible ty...
Article
Phocomelia
Phocomelia is an extremely rare congenital skeletal disorder that characteristically affects the limbs. It can affect either the upper limbs or lower limbs or both. Phocomelia is also a descriptive term to describe the characteristic limb anomalies occurring with its associated conditions.
Path...
Article
Fetal hepatomegaly
Fetal hepatomegaly (or more simply an enlarged fetal liver) can occur in number of situations. It can occur with or without fetal splenomegaly.
Pathology
Etiology
in utero infections: the commonest cause
fetal cytomegalovirus infection (CMV) 3
fetal parvovirus B19 infection
in utero syph...
Article
Tubal ring sign
The tubal ring sign, also referred to as a bagel sign or blob sign, is one of the ultrasound signs of a tubal ectopic pregnancy. 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.
Differe...
Article
Renal dysgenesis
Renal dysgenesis is a very broad term which can include any form underdevelopment of the kidneys. The spectrum includes:
renal agenesis: complete lack of formation
renal hypoplasia: partial lack of formation
Some authors also classify any form of renal maldevelopment affecting size, shape of ...
Article
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...
Article
Echogenic fetal lung lesions
Echogenic fetal lung lesions on antenatal ultrasound can be detected in a number of situations. They include:
Airway obstructions: lung are often enlarged and echogenic bilaterally
congenital high airways obstruction syndrome (CHAOS)
tracheal atresia
congenital tracheal stenosis
laryngeal a...
Article
Myelomeningocele
Myelomeningocele, also known as spina bifida cystica, is a complex congenital spinal anomaly that results in spinal cord malformation (myelodysplasia).
Epidemiology
It is one of the most common congenital CNS anomalies and is thought to occur in approximately 1:500 of live births 5. There may...
Article
Transient abnormal myelopoiesis
Transient abnormal myelopoiesis (TAM) is a phenomenon that can happen in the fetuses or neonates with trisomy 21. The condition can mimic leukemia.
Epidemiology
The estimated incidence is at ~10% of newborns with trisomy 21 3.
Radiographic features
Antenatal ultrasound
In the context of kno...
Article
Ampullary ectopic pregnancy
Ampullary ectopic pregnancy is the commonest type of tubal ectopic pregnancy and accounts for ~70% of such cases. According to one study, the disruption of the tubal wall was less than as in isthmic ectopic pregnancy 2.
Article
Isthmic ectopic pregnancy
An isthmic ectopic pregnancy is a subtype of tubal ectopic pregnancy an accounts for ~12% of such cases. According to one study, the rate of tubal wall disruption was higher than with an ampullary ectopic pregnancy, suggesting that in an isthmic ectopic pregnancy, the trophoblast penetrates the ...
Article
Hydranencephaly
Hydranencephaly is a rare encephalopathy that occurs in-utero. It is characterized by destruction of the cerebral hemispheres which are transformed into a membranous sac containing cerebrospinal fluid and the remnants of cortex and white matter 1.
Porencephaly is considered a less severe degree...
Article
Fetal ventriculomegaly (differential)
Fetal ventriculomegaly (ventricle width >10 mm) is an important finding in itself and it is also associated with other central nervous system abnormalities. For more information, see the main article fetal ventriculomegaly.
Differential diagnosis
Fetal ventriculomegaly can be thought of in ter...
Article
Corpus luteum
The corpus luteum (plural: corpora lutea) 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...
Article
Ovarian hyperstimulation syndrome
Ovarian hyperstimulation syndrome (OHSS) is a complication of controlled ovarian stimulation, which is an assisted reproduction technique used for in vitro fertilisation (IVF). Rarely, it may also occur spontaneously in pregnancy (see below). It consists of ovarian enlargement with an extravascu...
Article
Amniotic bands
Amniotic bands refer to free-floating blind-ending amnion with an intact chorionic membrane. In certain situations, they lead to amniotic band syndrome. They should not be confused with amniotic shelves which refer to the presence of amnion folding around pre-existing uterine adhesions. Some adv...
Article
Gestational trophoblastic disease
Gestational trophoblastic disease (GTD) results from the abnormal proliferation of trophoblastic tissue and encompasses a wide spectrum of diseases, including 14:
tumor-like lesions
exaggerated placental site reaction
placental site nodule and plaque
abnormal (non-molar) villous lesions
mol...
Article
Holoprosencephaly
Holoprosencephaly (HPE) is a rare congenital brain malformation resulting from incomplete separation of the two hemispheres.
Classically three subtypes have been recognized, however additional entities are now included in the spectrum of the disease. The three main subtypes, in order of decreas...
Article
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...
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