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.

153 results found
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Uhl anomaly

Uhl anomaly is an unusual cardiac disorder which affects the right ventricle where there is almost complete absence of right ventricular myocardium, normal tricuspid valve, and preserved septal and left ventricular myocardium. History and etymology It is named after Henry S D Uhl, who first de...
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UK vs. US English

There are numerous differences between United Kingdom (UK) and United States (US) English spelling and, as stated elsewhere, we accept having a mix of UK and US spelling on the site, while preferring the UK spelling for articles titles and content in our continuous aim for uniformity. 
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Ulcerative colitis

Ulcerative colitis is an inflammatory bowel disease that not only predominantly affects the colon, but also has extraintestinal manifestations. Epidemiology Typically ulcerative colitis manifests in young adults (15-40 years of age) and is more prevalent in males but the onset of disease after...
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Ulegyria

Ulegyria refers to a shrunken and flattened cortex due to global hypoxic ischaemic injury in term infants, centering on the deepest portion of gyri, usually in the parasagittal region. It is here that perfusion is most tenuous and, therefore, most susceptible to ischaemic damage. It is one of t...
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Ulna

The ulna (plural: ulnae) is one of the two long bones of the forearm. It is located medially in the supinated anatomic position. It has a larger proximal end and tapers to a smaller distal end (opposite to the radius).  Gross anatomy Prominent features of the ulna include: proximal: olecranon...
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Ulnar dimelia

Ulnar dimelia or mirror hand syndrome is a rare congenital anomaly of the upper limb characterized by absence of the radial ray (including thumb), duplication of the ulna and duplication of the ulnar halves of the carpals, metacarpals and phalanges 1. Pathology Embryology The embryology of mi...
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Ulnar hemimelia

Ulnar hemimelia is a rare congenital upper limb anomaly characterized by complete or partial absence of the ulna bone. Epidemiology Incidence is estimated at 1/100,000-150,000 live births, with a male to female ratio of 3:2. Associations Ulnar hemimelia may be associated with other skeletal ...
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Ulnar impaction syndrome

Ulnar impaction syndrome, also known as ulnar abutment or ulnocarpal loading, is a degenerative wrist condition caused by the ulnar head impacting upon the ulnar-sided carpus with injury to the triangular fibrocartilage complex (TFCC). Epidemiology Ulnar impaction syndrome most commonly presen...
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Ulnar impingement syndrome

Ulnar impingement syndrome is a wrist condition caused by a shortened distal ulna impinging on the distal radius proximal to the sigmoid notch. The syndrome is distinct from ulnar impaction syndrome, which typically occurs due to a long ulna (positive ulnar variance) impacting upon the triangula...
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Ulnar nerve

The ulnar nerve is one of the terminal branches of the brachial plexus and has motor and sensory supply to the forearm and hand. Gross anatomy Origin The ulnar nerve originates as a terminal branch of the medial cord of the brachial plexus with nerve root fibres from C8-T1. Course Arm In t...
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Ulnar nerve dislocation

Ulnar nerve dislocation is an uncommon cause of pain and paresthesias in the ulnar nerve distribution. It occurs if the ulnar nerve subluxates and then dislocates over the anterior aspect of the medial epicondyle during flexion and extension of the elbow.  Pathology Ulnar nerve dislocation occ...
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Ulnar styloid fracture

Ulnar styloid fractures occur in association with ~60% of distal radius fractures. Most of these are small avulsion fractures involving the tip of the ulnar styloid. Pathology Usually these kind of fractures occur as the result of a fall on an outstretched arm and are often associated with a d...
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Ulnar styloid impaction syndrome

Ulnar styloid impaction syndrome refers to wrist pain due to a long ulnar styloid process impacting upon the triquetral bone. Pathology An unlar styloid >6mm in length is commonly regarded as being long. Impaction results in chondromalacia of the opposing articular surfaces, i.e. the proxim...
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Ulnar variance

Ulnar variance (also known as Hulten variance) refers to the relative lengths of the distal articular surfaces of the radius and ulna.  Ulnar variance may be : neutral (both the ulnar and radial articular surfaces at the same level) positive (ulna projects more distally) negative (ulna proje...
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Ulnar-sided wrist impaction and impingement syndromes

There are several distinct ulnar-sided wrist impaction and impingement syndromes. Underlying anatomical causes exist for each syndrome however repetitive or excessive use of the forearm and wrist can also contribute. ulnar impaction syndrome: positive ulnar variance ulnar impingement syndrome:...
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Ulnomeniscal homologue

The ulnomeniscal homologue (UMH) is an obliquely oriented, fibrocartilaginous structure, that forms part of the ulnar collateral ligament complex (ULC). Gross anatomy The UMH is located between the ulnar styloid process and the triquetrum. It adheres to the ulnar joint capsule and merges with ...
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Ultrasound (introduction)

Ultrasound (US) is an imaging technology that uses high-frequency sound waves to characterize tissue. It is a useful and flexible modality in medical imaging, and often provides additional or unique characterization of tissues, compared with other modalities such as conventional radiography or C...
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Ultrasound appearances of liver metastases

Ultrasound appearance of liver metastases can have bewildering variation. Patterns do exist between ultrasound appearance of the liver metastases and the likely primary, which is sometimes helpful in directing search for an unknown primary, as well as helping distinguish between benign lesions ...
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Ultrasound artefacts

Ultrasound artefacts are commonly encountered and a knowledge is necessary to avoid false diagnosis. Artefacts acoustic shadowing acoustic enhancement beam width artefact comet tail artefact colour comet tail artefact mirror image artefact reverberation artefact ring down artefact refr...
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Ultrasound assessment of carotid arterial atherosclerotic disease

Ultrasound assessment of carotid arterial atherosclerotic disease has became the first choice for carotid artery stenosis screening, permitting the evaluation of both the macroscopic appearance of plaques as well as flow characteristics in the carotid artery. This article focus on internal caro...
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Ultrasound evaluation of breast cysts

Ultrasound evaluation of breast cysts is the modality of choice. Obstruction of the ducts, often appearing as the result of epithelial hyperplastic processes or the stromal fibrosis, or both processes lead to the formation of cysts, disabling the drainage of the terminal ducts of the lobules. I...
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Ultrasound frequencies

Ultrasound frequencies in diagnostic radiology range from 2 MHz to approximately 15 MHz.  It is important to remember that higher frequencies of ultrasound have shorter wavelengths and are absorbed/attenuated more easily. Therefore, higher frequencies are not as penetrating. This explains why h...
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Ultrasound guided biopsy

Ultrasound guided biopsy is one form of image guided biopsy, typically performed by a radiologist.  It is the most common form of image guided biopsy, offering convenience and real time dynamic observation with echogenic markers on cannulae allowing for precise placement. It can potentially be ...
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Ultrasound guided breast biopsy

Ultrasound guided percutaneous breast biopsy is a widely used technique for an accurate histopathological assessment of suspected breast pathology. It is a fast, safe and economical procedure. Indications Ultrasound guidance is limited to lesions visible on ultrasound study, such as:  BIRADS ...
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Ultrasound guided percutaneous drainage

Ultrasound guided percutaneous drainage is one form of image guided procedure, allowing minimally invasive treatment of collections that are accessible by ultrasound study. It has several advantages and disadvantages over CT, which include: Advantages is a dynamic study, allowing greater prec...
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Ultrasound guided peripheral intravenous cannulation

Ultrasound (US) guided peripheral intravenous cannulation (IVC) is the placement of a cannula into a peripherally located vein under the direct vision of ultrasound. This process allows the cannulation of veins that are unable to be visualised or palpated without ultrasound. In trained individua...
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Ultrasound of the elbow

Ultrasound of the elbow allows high resolution imaging of elbow anatomy while simultaneously allowing dynamic evaluation of the joint, tendons, and ligaments. Approach There are multiple possible approaches to imaging the elbow with ultrasound. A typical protocol is as follows 1: Anterior elb...
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Ultrasound of the hip (adult)

There are several approaches to ultrasound examination of the adult hip.  Anterior approach Patient positioning supine with the hip in mild external rotation Planes sagittal oblique plane parallel to the long axis of the femoral neck to assess femoral head and neck and for any joint effusio...
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Ultrasound of the knee

Ultrasound of the knee allows high resolution imaging of superficial knee anatomy while simultaneously allowing dynamic evaluation of some of the tendons and ligaments. Knee ultrasound is somewhat limited compared with ultrasound examinations of other joints because the cruciate ligaments and th...
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Ultrasound of the shoulder

Ultrasound of the shoulder is a fast, relatively cheap and dynamic way to examine the rotator cuff and is particularity useful in diagnosing: shoulder impingement shoulder instability rotator cuff disorders The examination requires attention to technique and appropriate patient positioning. ...
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Ultrasound of the wrist

Ultrasound is a useful imaging modality for evaluation of the wrist, allowing high resolution imaging of anatomy while simultaneously allowing dynamic evaluation of the joint, tendons, and ligaments. Approach There are multiple possible approaches to imaging the wrist with ultrasound. The exam...
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Ultrasound-guided FNA of the thyroid

Ultrasound-guided fine needle aspiration (FNA) of the thyroid refers to a minimally invasive procedure where in which tissue samples are collected from a thyroid nodule or other suspicious thyroid lesion. It is usually done on a outpatient basis and generally complications are very minimal. Pro...
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Umbilical arterial aneurysm

An umbilical arterial aneurysm (UAA) is an extremely rare but potentially lethal vascular anomaly which is usually detected in utero.  Pathology Location If tends to favour the placental end of the umbilical artery in the cord. Associations Concurrent associated anomalies are thought to be ...
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Umbilical arterial catheters

Umbilical arterial catheters are used in neonatal care and need to be carefully assessed on all neonatal films.  Position The catheter should pass through the umbilicus, travel inferiorly through the umbilical artery, then in the anterior division of the internal iliac artery, into the common ...
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Umbilical arterial Doppler assessment

Umbilical arterial (UA) Doppler assessment is used in surveillance of fetal well-being in the third trimester of pregnancy. Abnormal umbilical artery Doppler is a marker of uteroplacental insufficiency and consequent intrauterine growth restriction (IUGR) or suspected pre-eclampsia.  Umbilical ...
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Umbilical artery

The umbilical artery gives rise to both a nonfunctional remnant of the fetal circulation, and an active vessel giving supply to the bladder. In the adult the obliterated area of the vessel is identifiable as the medial umbilical ligament and the patent segment is the superior vesical artery. Su...
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Umbilical cord

The umbilical cord is a fetal organ and connects the placenta to the uterus and is a vital passage for nutrients, oxygen and waste products to and from the fetus.  The umbilical cord inserts into the centre of the placental bulk and into the fetus at the umbilicus. Variation in insertion can oc...
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Umbilical cord coiling index

Umbilical cord coiling index is defined as number of coils per one centimeter of length of the cord . Normal index is one coil for a length of five centimeters. If number of coils are more per centimeter it is called as hypercoiled and less than it is called as hypocoiled umbilical cord. This in...
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Umbilical cord cyst

Umbilical cord cyst can refer to any cystic lesion associated with the umbilical cord. They can be single (commoner) or multiple. Epidemiology They may be seen in ~3% of pregnancies in the first trimester 8. Pathology Umbilical cord cysts can represent either true or false cysts true cysts:...
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Umbilical cord entanglement

Umbilical cord entanglement is a feature which can mean either one of more loops of cord being encircled around any part of the any part of body 3 or two umbilical cord getting entangled with each other. In the latter situation it is a classical feature of a monochorionic-monoamniotic twin pregn...
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Umbilical cord haematoma

Umbilical cord haematoma is formation of a haematoma secondary to bleeding from the umbilical cord. Pathology The haematomas can be either spontaneous or iatrogenic. Spontaneous bleeding is very rare and documented to be around 0.02% of pregnancies. Majority of the cases are iatrogenic related...
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Umbilical cord knot

Umbilical cord knot is a term given to denote either true umbilical cord knot: often the term "umbilical cord knot" is used to describe this entity 1 or false umbilical cord knot: usually of no clinical significance See also umbilical cord entanglement
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Umbilical cord prolapse

Umbilical cord prolapse is a situation where the umbilical cord protrudes into the cervical canal. Epidemiology The estimated incidence is at  ~ 0.2-0.5% of all pregnancies 4,5.  Pathology Associations Recognised associations include multifetal pregnancy: twin gestation non cephalic/abnor...
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Umbilical cord pseudocyst

An umbilical cord pseudocyst is a type of cystic lesion occuring in relation to the umbilical cord. Epidemiology Although the true incidence not accurately known, they are comparatively much more common than true umbilical cord cysts. Pathology The pseudocyst basically comprises of mucoid de...
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Umbilical cord thrombosis

Umbilical cord thrombosis is a potentially fatal complication and can mean either a thrombosis of the umbilical vein or either or both the umbilical arteries. Umbilical vein thrombosis occurs more frequently than thrombosis of one or both umbilical arteries (umbilical arterial thrombosis) Epide...
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Umbilical hernia

Umbilical hernias are the most common ventral hernia and occur in the midline. Epidemiology Ten times more common in females 2 and represent ~5% of all abdominal hernias 4. Clinical presentation Umbilical hernias present in the midline as painless or painful mass.  Pathology Umbilical hern...
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Umbilical vein varix

Umbilical vein varix (UVV) refers to a focal dilatation of the umbilical vein. Pathology Location It tends to favour the intra-abdominal portion of the cord (typically between the abdominal wall and the liver) which is then termed a fetal intra-abdominal umbilical vein varix (FIUVV) or the in...
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Umbilical venous catheters

Umbilical venous catheters are commonly used in the neonatal period for vascular access, and should be carefully assessed for position on all neonatal films.  Position An umbilical venous catheter generally passes directly superiorly and remains relatively anterior in the abdomen. It passes th...
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Umbilical venous dilatation

Umbilical venous dilatation is a rare entity and often tends to occur as an isolated finding 4. It can arise from a number of patholgies umbilical venous varix (UVV): particularly if focal fetal hydrops: a focal dilatation due to an umbilical venous varix with an ensuing thrombosis can also ...
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Umbilical venous flow assessment

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  the presenc...
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Uncal herniation

Uncal herniation is a subtype of transtentorial downward brain herniation, usually related to cerebral mass effect increasing the intracranial pressure. ​Clinical presentation Abnormal posture and poor GCS. There may be pupillary dilation and loss of light reflex due to direct compression of t...
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Unclassified cerebellar dysplasia

Unclassified cerebellar dysplasia is defined as focal or diffuse dysplasia of cerebellar hemispheres or vermis not associated with other known malformations or syndromes. Clinical presentation Can present with hypotonia, microcephaly or speech delay. Radiographic features MRI brain asymmetr...
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Uncovertebral joint

Uncovertebral joints, also called Luschka’s joints, are seen bilaterally between adjacent cervical vertebrae, identified by the cat ear shaped uncinate processes of the C3-7 vertebrae (C1 and C2 have no uncinate processes). Gross anatomy Articulations The articulation forms between the uncina...
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Uncus

The uncus is the innermost part of the anterior parahippocampal gyrus, part of mesial temporal lobe.  Gross anatomy The uncus is the most anterior portion of the medial parahippocampal gyrus. It belongs to the limbic system. Housing the primary olfactory cortex, it is part of the olfactory sys...
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Undifferentiated carcinoma of the endometrium

Undifferentiated carcinoma of the endometrium is rare histological subtype of endometrial cancer. It is considered a high grade carcinoma, carries a poor prognosis and is often under-recognised 1. Epidemiology It is thought to represent approximately 1-9% of endometrial cancers 1,6. Pathology...
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Undifferentiated carcinoma of the ovary

An undifferentiated carcinoma of the ovary is a rare type of ovarian epithelial tumour. They account for ~ 4% of ovarian cancer 2. Pathology With these tumours, cellular differentiation is not sufficient for the tumour to be categorized into a serous or mucinous other specified sub type. Pure ...
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Undifferentiated spondyloarthritis

Undifferentiated spondyloarthritis (uSpA), also known as undifferentiated arthritis, is a non-specific mono- or polyarthropathy that lacks the clinical, serological and radiological features that would allow specific diagnosis. It often turns out to be an early presentation of a more well known ...
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Unfolded aorta

The term unfolded aorta refers to the widened and 'opened up' appearance of the aortic arch on a frontal chest radiograph. It is one of the more common causes for apparent mediastinal widening and is seen with increasing age. It occurs due to the discrepancy in the growth of the ascending aorta...
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Unfused spinous process

Unfused spinous process, which is really failure of fusion of the neural arch, is a relatively common anatomical variant and is part of the spectrum of spina bifida occulta.  This should be differentiated from accessory ossicles of the spinous process, which appear after non-fusion of the secon...
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Unicameral bone cyst

Unicameral bone cysts (UBC), also known as a simple bone cysts, are common benign non-neoplastic lucent bony lesions that are seen mainly in childhood and typically remain asymptomatic. They account for the S (simple bone cyst) in FEGNOMASHIC the commonly used mnemonic for lytic bone lesions.  ...
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Unicornuate uterus

A unicornuate uterus or unicornis unicollis is a type of Mullerian duct anomaly (class II).  This type can account for ~10% (range 6-13%) of uterine anomalies and infertility is seen in ~12.5% (range 5-20%) of cases. Pathology There is a failure of one müllerian duct to elongate while the othe...
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Unifocalisation procedure

A unifocalisation procedure is a corrective surgical technique used in patients with complete pulmonary artery atresia with major aortopulmonary collateral arteries (MAPCAs). In this technique, the collateral vessels supplying blood from the aorta directly to the lungs are brought into continuit...
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Unilateral facet dislocation

Unilateral facet dislocation is a relatively stable type of facet dislocation. Pathology Mechanism Flexion/distraction associated with rotation. The inferior articular facet of vertebral above moves over the superior facet of the vertebral below and becomes locked. It usually affects C4-C5 or...
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Unilateral hyperlucent hemithorax (mnemonic)

Mnemonics for a unilateral hyperlucent hemithorax include: CRAWLS SAFE POEM Mnemonics CRAWLS C: contralateral lung increased density, e.g. supine pleural effusion R: rotation A: air, e.g. pneumothorax W: wall, e.g. chest wall mass, mastectomy, polio, Poland syndrome L: lungs, e.g. airwa...
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Unilateral hypertranslucent hemithorax

Unilateral hypertranslucent hemithorax has many potential causes. It may be the result of rotation away from an optimal position or because of pathology. Rotation A unilateral hypertranslucent hemithorax may be caused by the positioning of the patient. Rotation away from the radiation beam alt...
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Unilateral pulmonary artery atresia

Unilateral pulmonary artery atresia (UPAA) or unilateral absence of the pulmonary artery (UAPA) is a variant of pulmonary artery atresia.  Epidemiology The estimated prevalence is around 1 in 200,000 young adults. The reported frequency on the right side is slightly greater for some reason 10....
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Unilateral pulmonary oedema

Unilateral pulmonary oedema represent only 2% of cardiogenic pulmonary oedema with predilection for the right upper lobe and is strongly associated with severe mitral regurgitation 1, 2. It is hypothesised that the regurgitation jet is directed towards the right superior pulmonary vein thus pref...
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Unilateral pulmonary vein atresia

Unilateral pulmonary vein atresia is a type of pulmonary vein atresia. Pathology It results from failure of incorporation of the common pulmonary vein into the left atrium. There is no recognised right or left predilection. Clinical presentation The condition usually present in infancy or ch...
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Unilateral testicular lesions

The differential diagnosis for unilateral testicular lesions is wide-ranging.  Neoplastic Common seminoma (40-50% of tumours) non seminomatous germ cell tumours: testicular teratoma testicular epidermoid (teratoma with ectodermal elements only) choriocarcinoma embryonal cell carcinoma y...
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Unlisted cases

Unlisted cases are great if you don't want other users to see them but still want to be able to easily share them with others.  Unlisted cases are: not... visible to other users when browsing Radiopaedia.org indexed by search engines like Google able to be added to articles able to be adde...
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Unlisted playlists

Unlisted playlists are a special type of playlist and a great way of creating collections of cases but restrict access to only some users.  Unlisted playlists are just the same as public playlists but are:  not visible to users not visible to search engines able to be shared (just click the ...
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Unroofed coronary sinus

An unroofed coronary sinus is a rare variant of atrial septal defect (ASD). The atrial wall between the coronary sinus and left atrium is either partially or completely absent, resulting in a left-to-right shunt. It is associated with persistent left-sided SVC and heterotaxy syndromes. Clinica...
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Unverricht-Lundborg disease

Unverricht-Lundborg disease (ULD) or EPM1) inherited neurodegenerative disorder which often results in myoclonic epilepsy. Epidemiology It is considered the most common single cause of progressive myoclonus epilepsy worldwide.   Pathology Genetics It carries an autosomal recessive inheritan...
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Upper and lower lobe distribution of bilateral pulmonary pathologies (mnemonic)

Many pulmonary disease are described as upper or lower lobe predominant. The following mnemonics can aid recall of these differential diagnosis.  upper lobe or apical predominance: SET CAP  lower lobe or bibasilar predominance: BAD RASH Mnemonics SET CAP S: silicosis/sarcoidosis E: EG/extr...
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Upper extremity dislocations

Upper extremity dislocations are relatively common on account of the great range of motion the upper limb is capable of (a general principle is that the greater the range of motion of a joint, the more prone it is to dislocation). In many instances dislocations are associated with fractures eith...
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Upper extremity fractures

The upper limb sustains a wide variety of fractures that range significantly in demographics, treatment and functional impact.  clavicle clavicular fracture acromio-clavicular dislocation scapula blade of scapula fracture glenoid fracture acromial fracture coracoid process fracture hume...
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Upper gastrointestinal bleeding

Upper gastrointestinal bleeding (UGIB) is defined as bleeding proximal to the ligament of Treitz. Epidemiology The incidence of acute UGIB is ~100 per 100,000 adults per year. UGIB is twice as common in men as in women and increases in prevalence with age 5. The demographics of the affected in...
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Upper gastrointestinal bleeding (haemorrhage) - differential diagnosis

An upper gastrointestinal bleed usually refers to bleeding proximal to the ligament of Treitz. Pathology Causes peptic ulcer gastritis oesophagitis duodenitis Mallory-Weiss tear varices tumour vascular abnormality vascular ectasia angiodysplasia Dieulafoy lesion vascular malformati...
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Upper limb anatomy

Upper limb anatomy encompasses the anatomy of the shoulder, arm, elbow, forearm, wrist and hand.
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Upper limb radiography

Upper limb radiography is the radiological investigation of the shoulder girdle, humerus, ulna, radius, carpals and metacarpals of the hand. It is often utilised in the context of trauma to rule out fractures and dislocations. 
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Upper lobe bronchiectasis

Distribution of bronchiectasis can help in narrowing the differential diagnosis. Upper lobe bronchiectasis is typically seen in: cystic fibrosis tuberculosis Rarely it may be seen with non tuberculous mycobacterial infection (e.g. MAC infection 2) When in mid-upper l...
Article

Upper lobe pulmonary fibrosis

Upper lobe predominant pulmonary fibrosis can be associated with a number of pathologies. These include cystic fibrosis - see pulmonary manifestations of cystic fibrosis pulmonary sarcoidosis Langerhans cell histiocytosis pulmonary tuberculosis pneumoconioses silicosis certain drug-induce...
Article

Upper lobe pulmonary fibrosis (mnemonic)

Conditions which lead to predominantly upper lobe pulmonary fibrosis can be remembered using the mnemonics: CASSET P ST CASH BREASTS Mnemonic CASSET P C: cystic fibrosis A: ankylosing spondylitis S: silicosis S: sarcoidosis E: eosinophilic granuloma (Langerhans cell histiocytosis) T: ...
Article

Upper lobe pulmonary venous diversion

Upper lobe pulmonary venous diversion (cephalisation) reflects elevation of left atrial pressure and can occur with pulmonary oedema. It produces Stag-antler's sign on frontal chest x-ray. The normal left atrial pressure is 5-10 mmHg. An elevation of left atrial pressure to 10-15 mmHg will resu...
Article

Upper subscapular nerve

The upper subscapular nerve, also known as the short or superior subscapular nerve, arises from the posterior cord of the brachial plexus and supplies the subscapularis muscle. Gross anatomy Origin The upper subscapular nerve branches from the posterior cord of the brachial plexus with fibres...
Article

Upper zone

The upper zone is one of the four chest radiograph zones. Sometimes the upper zone includes the apical zone.  Radiographic appearance Plain film on frontal chest radiographs, the upper zone extends from the inferior margin of the clavicles to the superior aspect of the hilum Related patholog...
Article

Urachal cyst

Urachal cysts are one of the manifestations of the spectrum of congenital urachal remnant abnormalities.  Clinical presentation Urachal cysts usually remain asymptomatic until complicated by infection or bleeding. Epidemiology Infected urachal cyst can occur at any age. Pathology Urachal c...
Article

Urachal umbilical sinus

A urachal umbilical sinus is one of the spectrum of congenital urachal remnant abnormalities, and represents a non-communicating dilatation of the urachus at the umbilical end. Clinical presentation Presentation is commoner in children and rare in adult. Radiographic features An umbilical-ur...
Article

Urachus

The urachus is the fibrous vestigal remnant of the fetal allantois. It usually obliterates after birth and the fibrous cord creates a linear fold of parietal peritoneum in the midline of the posterior aspect of the anterior abdominal wall extending from the apex of the bladder to the umbilicus, ...
Article

Uraemic encephalopathy

Uraemic encephalopathy (UE) is an acquired toxic syndrome characterised by delirium in patients with untreated or inadequately treated end-stage renal disease. UE is often associated with lethargy and confusion in the acute phase, which can progress to seizures, coma, or both in the chronic phas...
Article

Ureter

The ureter is a paired fibromuscular tube that conveys urine from the kidneys in the abdomen to the bladder in the pelvis.  Gross anatomy The ureter is 25-30 cm long and has three parts: abdominal ureter: from the renal pelvis to the pelvic brim pelvic ureter: from the pelvic brim to the bla...
Article

Ureteral duplication

Ureteral duplication is the most common congenital abnormality associated with the urinary tract, and occurs in ~1% of the population. Gross anatomy Duplication can occur unilaterally or bilaterally, and may be partial or complete: partially duplicated ureters fuse into a single ureter proxim...
Article

Ureteral pseudodiverticulosis

Ureteral pseudodiverticulosis is acquired false diverticula resulting from herniation of epithelium through the muscularis layer of the ureter and characterized by the presence of multiple outpouchings smaller than 5 mm. It is more commonly bilateral and located in the upper two-thirds of the ur...

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