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.
More than 200 results
Article
Pallister Killian syndrome
Pallister-Killian syndrome (PKS) is an extremely rare chromosomal anomaly.
Epidemiology
It may be more prevalent in births from women of advanced age 4.
Clinical presentation
Phenotypic expression can significantly vary from multiple anomalies resulting in perinatal death to the more charact...
Article
Abdominal distension (mnemonic)
A mnemonic for causes of abdominal distension (6 Fs) is:
F: fat
F: fluid
F: flatus
F: feces
F: fetus
F: fulminant mass
Article
First trimester
The first trimester is defined as the first 13 weeks of pregnancy following the last normal menstrual period (some authors refer to early pregnancy as 0-10 weeks). It can be divided into a number of phases, each of which has typical clinical issues. These phases are:
conceptus phase: 3-5 weeks
...
Article
Placental site trophoblastic tumor
Placental site trophoblastic tumors (PSTT) are rare and one of the least common (~0.2% 7) forms of gestational trophoblastic disease.
Epidemiology
Placental site trophoblastic tumors typically occur in women of reproductive age with an average age of ~30 years. They may occur after a normal pr...
Article
Umbilical cord
The umbilical cord is a fetal organ that connects the placenta to the developing fetus and is a vital passage for nutrients, oxygen and waste products to and from the fetus.
Gross anatomy
The umbilical cord inserts into the center of the placental bulk and into the fetus at the umbilicus. Vari...
Article
Fetal dosimetry
NB: Please consult original article(s) and discuss with your local radiology department/radiation physicist before making any clinical decision.
Although radiation exposure to the gravid uterus is to be avoided whenever possible, and only deliberately performed after careful weighing up of the ...
Article
Umbilical cord abnormalities
Abnormalities of the umbilical cord can be classified into 1:
Morphologic abnormalities
umbilical cord coiling
hypocoiled umbilical cord
hypercoiled umbilical cord
straight umbilical cord
umbilical cord length abnormalities
long umbilical cord
short umbilical cord
umbilical cord thickne...
Article
Inter twin membrane
The intertwin membrane refers to a membraneous separation between two fetuses in a twin pregnancy. Depending on the chorionicity and amnionicity, the membrane may have a number of layers
dichorionic diamniotic (DCDA) pregnancy
composed of two chorionic and two amniotic layers
usually has a t...
Article
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...
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
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
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...
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