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 edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

10,588 results found
Article

≤11 ribs (differential)

≤11 ribs is associated with a number of congenital abnormalities and skeletal dysplasias, including Down syndrome campomelic dysplasia kyphomelic dysplasias asphyxiating thoracic dysplasia (Jeune syndrome) short rib polydactlyly syndromes trisomy 18 chromosome 1, partial deletion syndrome...
Article

1.5T vs 3T

Comparing 1.5T vs 3T MRI systems identifies a number of differences; a 3T system has increased signal to noise ratio (SNR) increased spatial resolution increased temporal resolution increased specific absorption rate (SAR) increased acoustic noise Signal to noise ratio Theoretically, sign...
Article

14-3-3 protein

14-3-3 protein is found in the cerebrospinal fluid (CSF), and is currently used to help identify patients with sporadic Creutzfeldt-Jakob disease (sCJD).  In diagnosing sCJD, the sensitivity of 14-3-3 protein is 92% and the specificity is 80% 1. A negative 14-3-3 assay may be helpful in reducin...
Article

18q syndrome

18q syndrome is a rare chromosomal anomaly where there is a deletion of part of the long arm of chromosome 18.  Associated symptoms and findings vary widely, as does their severity.  Characteristic features include short stature, mental retardation and hypotonia, facial and distal skeletal abnor...
Article

1p19q codeletion

1p19q codeletion stands for the combined loss of the short arm chromosome 1 (“1p”) and the long arm of chromosome 19 (“19q”) and is recognised as genetic marker predictive of therapeutic response (both chemotherapy and combined chemoradiotherapy) and overall longer survival in patients with diff...
Article

2-hydroxyglutarate

2-hydroxyglutarate is a metabolite that accumulates in the brains of patients with IDH-1 mutated (IDH-1 positive) brain tumours, particularly diffuse low grade gliomas. Although not in widespread clinical use, it is likely that 2-hydroxyglutarate, which resonates at 2.25 ppm, will be able to be ...
Article

20° oblique projection

20° oblique projection is a troubleshooting projection used in mammography, especially in young women and in follow-up patients. Technique The C-arm is turned approximately 20° for a superomedio-inferolateral oblique. With the patient's feet pointing towards the unit and her torso turned sligh...
Article

2001 WHO classification of hepatic hydatid cysts

The 2001 World Health Organization (WHO) classification of hepatic hydatid cysts is used to assess the stage of hepatic hydatid cyst on ultrasound and is useful in deciding the appropriate management for it depending on the stage of the cyst. This classification was proposed by WHO in 2001 and a...
Article

2005 WHO histological classification of odontogenic tumours

The 2005 WHO histological classification of odontogenic tumours lays out a classification system for neoplasms and other tumours related to the odontogenic apparatus. At the time of writing (2016), it is still the most widely used classification system.  Classification Malignant tumours odont...
Article

2008 WHO classification of tumours of haematopoietic and lymphoid tissues

The 2008 WHO classification of tumours of haematopoietic and lymphoid tissues is at the time of writing (mid 2016) the most widely used classification system.   Classification Hodgkin lymphoma nodular lymphocyte predominance classical Hodgkin lymphoma nodular sclerosing mixed cellularity ...
Article

2014 WHO classification of endometrial stromal tumours

Endometrial stromal tumours (EST) constitute <2% of all uterine tumours and <10% of uterine mesenchymal neoplasms 1.  Over the past four decades, EST classification has gone through various modifications, starting from the earliest study by Norris and Taylor 2. This was primarily due to the rar...
Article

22q11.2 deletion syndrome

The 22q11.2 deletion syndrome, also known as the DiGeorge syndrome or velocardiofacial syndrome, is a syndrome where a small portion of the chromosome 22 is lost and results in a variable but a recognisable pattern of physical and behavioural features. Epidemiology The estimated incidence is a...
Article

3D ultrasound

Three dimensional (3D) ultrasound is a technique that converts standard 2D grayscale ultrasound images into a volumetric data set. The 3D image can then be reviewed retrospectively. The technique was developed for problem solving (particularly in obstetric/gynecologic exams) and potentially to r...
Article

4D syndrome

4D syndrome is a term given to syndromic glucagonomas, a type of pancreatic endocrine tumour. D: dermatitis (necrolytic migratory erythema, often involving the groin) D: diabetes D: deep vein thrombosis D: depression
Article

5-F risk factors for cholelithiasis (mnemonic)

The 5-F rule refers to risk factors for the development of cholelithiasis in an event of upper abdominal pain: fair: more prevalent in Caucasian population 1 fat: BMI >30 female gender fertile: one or more children forty: age ≥40 cholelithiasis can occur in young patients with a positive f...
Article

5-tier ACR system of radiologic breast findings

The 5-tier ACR system was a previously used system for classification of radiologic breast findings, proposed by the American College of Radiologists (ACR). It is no longer in widespread use, having been gradually superseded by the new 6-tier BIRADS classification system first published in 1992....
Article

5th metacarpal pit

The 5th metacarpal pit refers to the normal exaggeration of the pit-like depression in the head of fifth metacarpal.  It should not be mistaken for a fracture (old or new) or an erosion.
Article

a vs. an

In English writing the indefinite article 'a' is used in congruence with a noun of which not a particular one is indicated as opposed to 'the'. For instance 'the house' is a particular house that can be identified, whereas 'a house' does not reference one house specifically. When the word follo...
Article

A-rings (oesophagus)

A-rings are a type of distal oesophageal ring. They are above the B-ring and occur a few centimetres proximal to the gastro-oesophageal junction. They represent a physiological contraction of oesophageal smooth muscle covered by mucosa. A-rings are uncommonly symptomatic.
Article

Aarskog syndrome

Aarskog syndrome or Aarskog–Scott syndrome (also known as the facio-digito-genital syndrome) is a rare anomaly characterized by short stature in association with a variety of structural anomalies involving mainly the face, distal extremities, and external genitalia. Clinical presentation The m...
Article

Aase-Smith syndrome

Aase-Smith syndrome is an extremely rare congenital disorder. Clinical features congenital hypoplastic anaemia - fetal anaemia triphalangeal thumbs broad thumb abnormal clavicles cleft lip, cleft palate hypoplastic radii hydrocephalus (due to Dandy-Walker anomaly) joint contractures na...
Article

AAST injury scoring scales

The American Association for the Surgery of Trauma (AAST) injury scoring scales are the most widely accepted and used system of classifying and categorising traumatic injuries. Injury grade reflects severity, guides management, and aids in prognosis. At the time of writing (mid 2016), 32 differe...
Article

AAST kidney injury scale

The AAST (American Association for the Surgery of Trauma) renal injury scale 3-4 is the most widely used renal trauma grading system at the time of writing (late 2016). Severity is assessed according to the depth of renal parenchymal damage and involvement of the urinary collecting system and re...
Article

AAST liver injury scale

The 1994 revision of the AAST (American Association for the Surgery of Trauma) liver injury scale is the most widely used liver injury grading system at the time of writing (late 2016).  Classification grade I haematoma: subcapsular, <10% surface area laceration: capsular tear, <1 cm  parenc...
Article

AAST spleen injury scale

The 1994 revision of the American Association for the Surgery of Trauma (AAST) splenic injury scale is the most widely used grading system for splenic trauma at the time of writing (late 2016).  Classification grade I subcapsular haematoma <10% of surface area capsular laceration <1 cm depth...
Article

ABC/2

ABC/2 is a fast and simple method for estimating the volume of intracerebral haemorrhage (or any other ellipsoid lesion for that matter) which does not require volumetric 3D analysis or software. Intracerebral haemorrhage volume is an important predictor of morbidity and mortality (and thus tria...
Article

Abdomen (AP supine view)

AP supine radiograph can be performed as a standalone projection or as part of an acute abdominal series, depending on the clinical question posed, local protocol and the availability of other imaging modalities. Patient position the patient is supine, lying on their back, either on the X-ray ...
Article

Abdomen (lateral decubitus view)

The lateral decubitus abdominal radiograph is used to identify free intraperitoneal gas (pneumoperitoneum). It can be performed when the patient is unable to be transferred to, or other imaging modalities (e.g. CT) are not available. The most useful position for detecting free intraperitoneal ai...
Article

Abdomen (PA erect view)

The PA erect abdominal radiograph is often obtained in conjunction with the AP supine abdominal view in the acute abdominal series of radiographs. When used together it is a valuable projection in assessing air fluid levels, and free air in the abdominal cavity. Patient position the patient is...
Article

Abdominal adhesions

Abdominal adhesions are bands of scar tissue (fibrous or fibrous fatty), most often occurring as a complication of previous abdominal surgery. Pathology Adhesions often occur with multiple abdominal operations or previous postoperative intra-abdominal complications history of intra-abdominal i...
Article

Abdominal and pelvic anatomy

Abdominal and pelvic anatomy encompasses the anatomy of all structures of the abdominal and pelvic cavities.
Article

Abdominal aorta

The abdominal aorta is the main blood vessel in the abdominal cavity that transmits oxygenated blood from the thoracic cavity to the organs within the abdomen and to the lower limbs. Summary origin: continuation of descending thoracic aorta at T12  course: descends anterior and slightly to th...
Article

Abdominal aortic aneurysm

Abdominal aortic aneurysms (AAA) are focal dilatations of the abdominal aorta that are 50% greater than the proximal normal segment or that are >3 cm in maximum diameter. Epidemiology Its prevalence increases with age. Males are much more commonly affected than females (with a male: female rat...
Article

Abdominal aortic aneurysm (summary)

Abdominal aortic aneurysms (AAA) are focal dilatations of the abdominal aorta that are 50% greater than the proximal normal segment or >3 cm in maximum diameter. Reference article This is a summary article; read more in our article on abdominal aortic aneurysm. Summary epidemiology prevalen...
Article

Abdominal aortic aneurysm rupture

Abdominal aortic aneurysm (AAA) rupture is a feared complication of abdominal aortic aneurysm and is a surgical emergency. It is part of the acute aortic syndrome spectrum. Epidemiology Abdominal aortic aneurysms are common and affect ~7.5% of patients aged over 65 years 6. Clinical presentat...
Article

Abdominal aortic injury

Abdominal aortic injuries are very rare and are much less common than thoracic aortic injury.  Epidemiology Aortic injury occurs in <1% of blunt trauma patients, with abdominal aortic injury representing only ~5% of all aortic injuries 1. Males are more frequently injured, with the median age ...
Article

Abdominal cavity

The abdominal cavity is divided into two major compartments, the peritoneum and retroperitoneum, early in fetal development. The parietal peritoneum is reflected over the peritoneal organs to form a series of supporting peritoneal ligaments, mesenteries and omenta. The peritoneal reflections ca...
Article

Abdominal ectopic pregnancy

Abdominal ectopic pregnancies are an extremely rare type of ectopic pregnancy. Epidemiology They are thought to represent ~1% of all ectopic pregnancies 6 with an estimated incidence of 1:1000-10,000 births. Pathology It is often thought that they most frequently result from a tubal rupture ...
Article

Abdominal hernia

Abdominal herniations may be congenital or acquired and come with varying eponyms. They are distinguished primarily based on location and content. 75-80% of all hernias occur in the inguinal region. Content of the hernia is variable, and may include: small bowel loops mobile colon segments (s...
Article

Abdominal opacities

An opacity projecting over the abdomen has a broad differential. Possibilities to consider include: foreign bodies ingested, e.g. coins, batteries, bones, etc. artifacts, e.g. object attached to the cloth of the patient like a safety pin or button iatrogenic, e.g. haemostatic clips, gastric ...
Article

Abdominal organ echogenicity (mnemonic)

This mnemonic helps to remember the relative echogenicity of abdominal organs on ultrasound: Darling Parents So Love Kids Mnemonic From most to least echogenic: D: diaphragm P: pancreas S: spleen L: liver K: kidneys(cortex)
Article

Abdominal paracentesis

Abdominal paracentesis, more commonly referred to as an ascitic tap, is a procedure that can be performed to collect peritoneal fluid for analysis or as a therapeutic intervention. Indications diagnostic: especially for newly diagnosed ascites determine aetiology of ascites assess for bacter...
Article

Abdominal radiograph (AP supine view neonatal)

AP supine radiograph for neonates is a mobile examination performed on the neonatal unit. It can be taken as a standalone projection or as part of a series including a left lateral decubitus x-ray in cases of suspected perforation.  Patient position the patient is supine, lying on their back i...
Article

Abdominal radiograph (lateral view)

The lateral view abdominal radiograph is a useful problem-solving view that can complement frontal views of the abdomen. It is different than the lateral decubitus view of the abdomen and looks more like a lateral lumbar spine view. Patient position the patient may be either erect or recumbent...
Article

Abdominal radiography

Abdominal radiography can be useful in many settings. Before the advent of computerised tomography (CT) imaging, it was a primary means of investigating gastrointestinal pathology (and often allowed indirect evaluation of other abdominal viscera). Indications Although abdominal radiography has...
Article

Abdominal radiology for students (curriculum)

Abdominal radiology curriculum for medical students is broadly split into content that refers to imaging (the test and findings) and conditions that are considered key for this stage of training. Some non-abdominal conditions are included in this portion of the curriculum, including breast dise...
Article

Abdominal radiology: conditions (curriculum)

Abdominal radiology conditions are a broad group of heterogeneous conditions that are split into: true pathology (e.g. colonic carcinoma) the underlying process (e.g. large bowel obstruction) It is important to have an overview of these conditions and understand what imaging is useful in thei...
Article

Abdominal radiology: imaging (curriculum)

Imaging in general surgery is vital to ensure timely and accurate diagnosis for patients.  You need to know the gamut of tests that are available when to use the correct test, some important findings that commonly occur and (for some investigations) how to approach looking at the images that ar...
Article

Abdominal radiology: interpretation (curriculum)

Abdominal radiology interpretation is a key component of how to make the most of diagnostic imaging. You need to know how to look at the commonly performed radiology tests and how to make common diagnoses.
Article

Abdominal radiology: key findings (curriculum)

Abdominal radiology key findings are a group of imaging findings that are really important in imaging of the abdomen. They point to disease processes and help to narrow the differential diagnosis. It is important to know these and recognise them on imaging.
Article

Abdominal radiology: presentations (curriculum)

Abdominal radiology presentations are a relatively distinct group of presentations that precipitate assessment medical and surgical teams.
Article

Abdominal radiology: tests and when to use them (curriculum)

Abdominal radiology tests and when to use them are a set of articles that help to outline the common tests that may be used in radiology and what they are useful for. Plain films (erect chest and supine abdomen), as well as ultrasound and CT abdomen, will be the bread and butter of the imaging ...
Article

Abdominal surface anatomy

The abdomen, when looking from in front, is divided into nine regions by imaginary planes (two vertical and two horizontal) forming abdominal surface anatomy. The nine regions are of clinical importance when examining and describing pathologies related to the abdomen. The horizontal planes are o...
Article

Abdominal trauma

Abdominal trauma is usually divided into blunt and penetrating trauma. Findings of abdominal trauma haemoperitoneum splenic trauma: most common hepatic trauma renal trauma pancreatic trauma gastrointestinal tract (bowel) trauma: proximal jejunum is most commonly affected by blunt trauma,...
Article

Abdominal x-ray - an approach (summary)

Abdominal radiographs can be challenging examinations to look at. It is always best to approach radiographs in a systematic way. Bowel gas pattern Gas within the bowel forms a natural contrast with surrounding tissues since it has a very low density. Bowel can only be seen if it contains air/g...
Article

Abdominal x-ray (summary)

Abdominal radiographs can be a useful examination, but you need to think about the question you are asking before getting the test. Before the advent of computerised tomography (CT) imaging, it was a primary means of investigating gastrointestinal pathology (and often allowed indirect evaluation...
Article

Abdominoschisis

Abdominoschisis refers to a split or in the abdominal wall. Some authors use the term synonymously with a gastroschisis. When the defect continues into the thoracic region it is termed a thoraco-abdominoschisis. A large abdominoschisis is considered part of the limb body wall complex 2. See als...
Article

Abducens nerve

The abducens nerve is the sixth cranial nerve. It courses from its nucleus located in the dorsal pons to its innervation of the lateral rectus muscle and can be divided into four parts: nucleus and intraparenchymal portion cisternal portion cavernous sinus portion orbital portion Gross anat...
Article

Abductor digiti minimi (foot)

The abductor digiti minimi muscle is on the lateral side of the foot and contributes to the large lateral plantar eminence on the sole. Summary origin: lateral and medial processes of calcaneal tuberosity, and band of connective tissue connecting calcaneus with base of metatarsal V insertion:...
Article

Abductor digiti minimi (hand)

The abductor digiti minimi muscle overlies the opponens digiti minimi. Summary origin: pisiform, the pisohamate ligament, and tendon of flexor carpi ulnaris insertion: 5th proximal phalanx action: abducts 5th finger at metacarpophalangeal joint arterial supply: ulnar artery innervation: de...
Article

Abductor hallucis muscle

The abductor hallucis muscle forms the medial margin of the foot and contributes to a soft tissue bulge on the medial side of the sole. Summary origin: medial process of calcaneal tuberosity insertion: medial side of base of proximal phalanx of great toe action: abducts and flexes great toe ...
Article

Abductor pollicis brevis

The abductor pollicis brevis is a thin subcutaneous muscle located laterally in the thenar eminence of the hand. Summary origin: mainly from the flexor retinaculum few fibres originate from the tubercles of scaphoid and trapezium and tendon of abductor pollicis longus accessory slips may ori...
Article

Abductor pollicis longus

The abductor pollicis longus (APL) is a muscle found in the deep layer of the posterior compartment of the forearm. As it descends, it becomes superficial and passes under the extensor retinaculum and through the 1st extensor compartment of the wrist before attaching distally. Summary origin: ...
Article

ABER position

The ABER position relates to MR arthrography of the shoulder joint and is a mnemonic for ABduction and External Rotation. In this position, labral tears are made conspicuous by tightening the inferior glenohumeral labroligamentous complex (which are also the most important glenohumeral ligament...
Article

Abernethy malformation

Abernethy malformations are rare vascular anomalies of the splanchnic venous system. They comprise of congenital portosystemic shunts and result from persistence of the embryonic vessels.  Epidemiology Type I malformations are thought only to occur in females with type II having a male predile...
Article

Aberrant arachnoid granulations

Aberrant arachnoid granulations (AbAG) are arachnoid granulations that penetrated the dura but failed to migrate normally in the venous sinus. They are most often located in the greater wing of the sphenoid bone. Occasionally, they are seen at the posterior temporal bone wall. Clinical presenta...
Article

Aberrant internal carotid artery

Aberrant internal carotid artery is a variant of the internal carotid artery (ICA) and represents a collateral pathway resulting from involution of the normal cervical portion (first embryonic segment) of the ICA 5. There is consequent enlargement of the usually small collaterals which course t...
Article

Aberrant left pulmonary artery

Aberrant left pulmonary artery, also known as pulmonary sling, represents an anatomical variant characterised by the left pulmonary artery arising from the right pulmonary artery and passing above the right main bronchus and in between the trachea and oesophagus to reach the left lung. It may le...
Article

Aberrant right subclavian artery

Aberrant right subclavian arteries (ARSA), also known as arteria lusoria, are the commonest of the aortic arch anomalies 2.  Epidemiology The estimated incidence is 0.5-2%. Clinical presentation They are often asymptomatic, but around 10% of people may complain of tracheo-oesophageal symptom...
Article

Aberrations in the normal development and involution of the breast

Aberrations in the Normal Development and Involution of the breast (ANDI) is an all-encompassing term that is used to describe a wide spectrum of the benign breast diseases. As the name suggests, it is based on the theory that most of the encountered benign breast disorders are essentially minor...
Article

Abnormal bowel wall attenuation patterns

Abnormal bowel wall attenuation patterns on CT scan can be grouped under five categories: white enhancement gray enhancement water halo sign fat halo sign black attenuation The first three patterns are seen on contrast studies. White enhancement It is defined as uniform enhancement of th...
Article

Abnormal collection of barium anywhere (mnemonic)

A mnemonic used for abnormal collection of barium anywhere in the body : FEDUP Mnemonic F: fistula E: extravasation D: diverticulum U: ulcer P: perforation
Article

Abnormal ductus venosus waveforms

Abnormal ductus venosus waveforms can arise in a number of conditions ranging from aneuploidy to vascular malformations and fetal tumours.  Pathology Abnormal waveforms in fetal ductus venosus flow assessment can occur in a number of situations: aneuploidic anomalies Down syndrome: around 80...
Article

Abnormal intra-abdominal gas

Abnormal intra-abdominal gas is an important radiologic finding with many potential causes. It may be seen on a chest radiograph, abdominal radiograph, CT or MRI. pneumoperitoneum retropneumoperitoneum pseudopneumoperitoneum abnormally located bowel, e.g. Chilaiditi syndrome (bowel interpose...
Article

Abnormal renal rotation

Abnormal renal rotation (renal malrotation) refers to an anatomical variation in the position of the kidneys, in particular to anomalous orientation of the renal hilum. It may occur unilaterally or bilaterally. It is almost always an asymptomatic incidental finding.  Epidemiology Malrotation i...
Article

Abnormal ultrasound findings in rheumatological diseases (definitions)

The OMERACT ultrasound group published a consensus in 2005 of widely accepted definitions of abnormal ultrasound findings in rheumatological diseases: erosion: an intra-articular discontinuity of the bone surface that is visible in two orthogonal planes joint effusion: abnormal hypoechoic or a...
Article

Abnormally eccentric gestational sac

An eccentrically located gestational sac towards the fundus of uterus is the normal sonographic appearance; however an abnormally eccentric gestational sac on ultrasound may be apparent due to a number of causes They include interstitial ectopic pregnancy 1 normally implanted pregnancy in a  ...
Article

Abnormally low sac position

An abnormally low sac position can result from several possibilities which include impending / ongoing miscarriage cervical ectopic pregnancy fundal fibroid or other mass compressing the sac downward
Article

Abnormally thickened endometrium (differential)

Abnormally thickened endometrium on imaging may occur for a number of reasons which may be categorised based on whether or not they are related to pregnancy. Aetiologies may also be classified based on whether the patient is premenopausal or postmenopausal. Differential diagnosis Pregnancy-rel...
Article

ABR certifying exam

The ABR certifying exam is the second of two exams necessary for certification in diagnostic and interventional radiology in the United States of America (the first is the core exam). It is taken 15 months after the end of the PGY 5 year (or three months after a one year PGY 6 fellowship). The ...
Article

ABR core exam

The ABR core exam is the first of two exams necessary for certification in diagnostic and interventional radiology in the United States of America. It is taken at the end of the PGY 4 year of radiology residency training. The exam is computer-based and occurs in two sessions (7.5 hours and 6 ho...
Article

Abscess

Abscesses are focal confined collections of suppurative inflammatory material and can be thought of as having three components 1: a central core comprised of necrotic inflammatory cells and local tissue peripheral halo of viable neutrophils surrounded by a 'capsule' with dilated blood vessels...
Article

Absent bow tie sign (knee)

The absent bow tie sign represents the loss of the normal appearance of the menisci on parasagittal MRI images, and is suggestive of meniscal injury. Normally the medial and lateral menisci appear as low signal bow-tie-shaped structures between the femoral condyles and tibial plateaux. As the n...
Article

Absent ductus venosus

Agenesis of the ductus venosus (ADV) is a rare fetal vascular anomaly. According to the data obtained from the screening tests performed at 11-14 weeks of pregnancy, its incidence is reported to be 1/2500 (12). Pathology In the literature review on ductus venosus agenesis, Acherman et.al (13) ...
Article

Absent fetal stomach on ultrasound (differential)

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). Causes include: physiological emptying: transient ...
Article

Absent infrarenal inferior vena cava

An absent infrarenal inferior vena cava (IVC) can be congenital due to failure of development of the posterior cardinal and supracardinal veins, or acquired as result of intrauterine or perinatal inferior vena cava thrombosis. Epidemiology It is an extremely rare anomaly. Clinical presentatio...
Article

Absent nasal bone

In fetal sonographic assessment, an absent nasal bone is a feature which can sometimes be used as an adjunctive marker for fetal aneuploidy. Radiographic assessment Antenatal ultrasound It is assessed on a midline sagittal view. In this section the nasal bone is often seen as a bright echogen...
Article

Absent patella

An absent patella is a rare finding and can be found with an equally rare set of associations: surgical removal of patella (patellectomy) nail patella syndrome 2 popliteal pterygium syndrome proximal focal femoral deficiency (PFFD) Meier-Gorlin syndrome 3
Article

Absent septum pellucidum

An absent septum pellucidum may rarely be an isolated finding, or more commonly be seen in association with a variety of conditions. Epidemiology The septum pellucidum is partly or entirely absent in 2 or 3 individuals per 100,000 in the general population.  Pathology An absent septum pelluc...
Article

Absent thumb

An absent thumb can have many associations. They include: Fanconi anaemia (pancytopenia-dysmelia syndrome) Franceschetti syndrome Holt-Oram syndrome phocomelia (e.g. thalidomide embryopathy) Poland syndrome (pectoral muscle aplasia and syndactyly) Rothmund-Thomson syndrome Seckel syndrome...
Article

Absent umbilical arterial end diastolic flow

Absent end diastolic flow (AEDF) in an umbilical artery Doppler assessment is a useful feature which indicates underlying fetal vascular stress if detected in mid or late pregnancy. It is often classified as Class II in severity in abnormal umbilical arterial Dopplers 9. Pathology The presence...
Article

Absent yolk sac

Absence of the yolk sac in the presence of an embryo on a transvaginal ultrasound is considered abnormal, and in general is associated with subsequent embryonic death. See also yolk sac
Article

Absorbed dose

Absorbed dose is a measure of the energy deposited in a medium by ionizing radiation. It is equal to the energy deposited per unit mass of medium, and so has the unit J/kg or gray (Gy) where 1Gy = 1Jkg-1. The absorbed dose is not a good indicator of the likely biological effect. 1 Gy of alpha r...

Updating… Please wait.
Loadinganimation

Alert accept

Error Unable to process the form. Check for errors and try again.

Alert accept Thank you for updating your details.