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.

412 results found
Article

Technetium agents

Technetium agents based on the technetium-99m (Tc-99m) radioisotope are frequently used agents in medical imaging. The radioactive technetium radiotracer can be chelated to a number of different compounds to create specific radiopharmaceuticals and optimise the functional imaging of various stru...
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Tetralogy of Fallot

Tetralogy of Fallot (TOF) is the second most common cyanotic congenital heart condition and has been classically characterised by the combination of ventricular septal defect (VSD), right ventricular outflow tract obstruction (RVOTO), overriding aorta, and a late right ventricular hypertrophy. ...
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Tetralogy of fallot (mnemonic)

A mnemonic for the underlying anatomic defects in tetralogy of Fallot is: PROVe Mnemonic P: pulmonary stenosis R: right ventricular hypertrophy O: overriding aorta V: ventricular septal defect
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Thallium-201 chloride

Thallium-201 chloride is a radiopharmaceutical used primarily in cardiac imaging. Characteristics photon energy: 80 keV physical half life: 73 hours biological half life rest: 3 minutes exercise: 30 seconds normal distribution: myocardium, skeletal muscle, GI tract, liver, kidneys excret...
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Third mogul sign

The third mogul sign can be seen on frontal chest radiograph in the presence of left atrial enlargement. It refers to an extra mogul or bump along the upper left cardiac silhouette just below the left main bronchus. The third mogul sign commonly represents the enlarged left atrial appendage, pa...
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Thoracic aorta

The thoracic aorta is the most superior division of the aorta and is divided into three sections: ascending aorta aortic arch descending aorta The thoracic aorta begins at the aortic valve, located obliquely just to the left of the midline at the level of the the third intercostal space. It ...
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Thrombolysis in myocardial infarction (TIMI) risk score

The thrombolysis in myocardial infarction (TIMI) risk score is a prognostic risk stratification system that categorises the risk of death and ischemic events in patients with unstable angina / NSTEMI and provides a basis for therapeutic decision making. It is thought to have potential to improve...
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Total anomalous pulmonary venous return

Total anomalous pulmonary venous return (TAPVR) is a cyanotic congenital heart anomaly with an abnormal drainage anatomy of the entire pulmonary venous system. This contrasts with partial anomalous pulmonary venous return (PAPVR) where only part of the pulmonary venous anatomy is abnormal. In T...
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Total repair of tetralogy of Fallot

Total repair of tetralogy of Fallot is a corrective surgical procedure that involves closure of the ventricular septal defect (VSD) and relief of right ventricular outflow tract (RVOT) obstruction. Procedure Most patients with tetralogy of Fallot (TOF) undergo elective surgical repair between ...
Article

Transcatheter aortic valve implantation (TAVI)

Transcatheter aortic valve implantation or replacement (TAVI/TAVR) is a technique to replace the aortic valve through a transvascular or transapical approach. Compared to traditional open aortic valve replacement with sternotomy and a heart-lung bypass machine, the TAVI technique is less invasiv...
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Transient ischaemic dilatation

Transient ischaemic dilatation (TID) is a paradoxical phenomenon seen in myocardial perfusion SPECT imaging.   With severe balanced coronary artery disease, myocardial ischaemia may result in apparent enlargement of the left ventricular cavity during stress. The cause of this is not entirely cl...
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Transposition of the great arteries

Transposition of the great arteries (TGA) is the most common cyanotic congenital cardiac anomaly with cyanosis in the first 24 hours of life. It accounts for up to 7% of all congenital cardiac anomalies 1  and can be assessed with echocardiography, gated cardiac CT, or cardiac MRI. Epidemiology...
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Transverse pericardial sinus

The transverse pericardial sinus is the transverse communication between the left and right parts of the pericardial space proper behind the two outflow arteries of the heart.   Gross anatomy It is superior to the left atrium and posterior to the intrapericardial parts of the pulmonary trunk a...
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Traumatic aortic injury in the exam

Getting a film with traumatic aortic injury in the exam is one of the many exam set-pieces that can be prepared for.  This is one of the cases you should look and not speak for 10 seconds as there tends to be a lot of findings on the film of patients with traumatic aortic injury. Description ...
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Tricuspid atresia

Tricuspid atresia is a cyanotic congenital cardiac anomaly which is characterised by agenesis of the tricuspid valve and right ventricular inlet. There is almost always an obligatory intra-atrial connection through either an ASD or patent foramen ovale (PFO) in order for circulation to be comple...
Article

Tricuspid valve

The tricuspid valve is one of the four cardiac valves. It is the atrioventricular valve that allows blood to flow from the right atrium to the right ventricle. It opens during diastole and closes during systole. The valve has anterior, posterior and septal leaflets (cusps), the bases of which at...
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Tricuspid valve regurgitation

Tricuspid valve regurgitation, also known as tricuspid valve insufficiency or tricuspid valve incompetence, is a valvulopathy that describes leaking of the tricuspid valve during systole that causes blood to flow in the reverse direction from the right ventricle into the right atrium. Epidemiol...
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Tricuspid valve stenosis

Tricuspid valve stenosis is a valvulopathy that describes narrowing of the opening of the tricuspid valve between the right ventricle and the right atrium. Epidemiology MS is seen more commonly in women and in countries, generally developing nations, where rheumatic fever is common 1,2. Clini...
Article

Triple-rule-out CT

Triple-rule-out CT (TRO CT) angiography may be ordered in the setting of acute chest pain to examine the thoracic aorta and the coronary and pulmonary arteries. The protocol helps exclude life-threatening causes of acute chest pain, especially if atypical, or if alternative causes to acute coron...
Article

Troponin elevation

Troponin elevation can occur from a number causes although there is no imaging involved, it is useful for the radiologist to have a basic understanding of their causes (especially when interpreting imaging findings associated with troponin elevation). The cardiac troponin complex consists of thr...
Article

Truncus arteriosus

Truncus arteriosus is a cyanotic congenital heart anomaly in which a single trunk supplies both the pulmonary and systemic circulation, instead of a separate aorta and a pulmonary trunk. It is usually classified as a conotruncal anomaly. It accounts for up to 2% of congenital cardiac anomalies ...
Article

Tuberous sclerosis

Tuberous sclerosis (TS), also known as tuberous sclerosis complex or Bourneville disease, is a neurocutaneous disorder (phakomatosis) characterised by the development of multiple benign tumours of the embryonic ectoderm (e.g. skin, eyes, and nervous system). Epidemiology Tuberous sclerosis has...
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Tuberous sclerosis diagnostic criteria

The tuberous sclerosis diagnostic criteria have been developed to aid the diagnosis of tuberous sclerosis and have been adapted from Roach et al 1998 1: definitive TS complex: either 2 major features or 1 major and 2 minor probable TS complex: 1 major and 1 minor possible TS complex: either 1...
Article

Twiddler syndrome

Twiddler syndrome occurs when a patient manipulates (rotates) a subcutaneous chest device to the point of detaching and retracting the distal portion of the device. It is most commonly seen with implanted cardiac pacemakers or implantable cardiac defibrillators (ICDs). With continued rotation, ...
Article

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...
Article

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...
Article

Unilateral pulmonary vein atresia

Unilateral pulmonary vein atresia is a type of pulmonary vein atresia. Clinical presentation The condition usually present in infancy or childhood with recurrent episodes of pneumonia and/or haemoptysis. Presentation in adulthood does occur but is uncommon. Pathology It results from failure ...
Article

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...
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 a frontal chest x-ray. The normal left atrial pressure is 5-10 mmHg. An elevation of left atrial pressure to 10-15 mmHg will re...
Article

Vagoglossopharyngeal neuralgia

Vagoglossopharyngeal neuralgia is an uncommon presentation of glossopharyngeal neuralgia where the typical symptoms of pain are associated with cardiac symptoms including arrhythmias, asystole, and syncope. It is believed to be due to complex interconnections between the nervus intermedius, the...
Article

Valvular heart disease

Valvular heart diseases, or cardiac valvulopathies, describe any acquired or congenital disease affecting one or more of the four cardiac valves. This is a general index article that classifies cardiac valvulopathies depending on which valve(s) is affected 1. See individual articles for in-dept...
Article

Vein of Marshall

The vein of Marshall, oblique vein of Marshall or the oblique vein of the left atrium is a small vein that descends on and drains the posterior wall of the left atrium. It drains directly into the coronary sinus at the same end as the great cardiac vein, marking the origin of the sinus. It repr...
Article

Venae cordis minimae

The venae cordis minimae (smallest cardiac veins or thebesian veins) are a small group of valveless myocardial coronary veins within the walls of each of the 4 cardiac chambers that drain venous blood directly into each of the respective chambers. They are most frequent in the right atrium and t...
Article

Ventricular septal defect

Ventricular septal defects (VSD) represent defects in the interventricular septum that allow a haemodynamic communication between the right and left ventricles. It typically results in a left-to-right shunt. Epidemiology They represent one of the most common congenital cardiac anomalies and ma...
Article

Walking man sign (chest x-ray)

The walking man sign is seen on a lateral chest radiograph and is a sign of left atrial enlargement. It results from posterior displacement of the left main bronchus such that it no longer overlaps the right bronchus. The left and right bronchus thus appear as an inverted 'V', mimicking the legs...
Article

Watchman device

Watchman device is a permanent left atrial appendage closure device, which is percutaneously implanted to prevent embolisation of thrombus from the appendage into the systemic circulation in cases atrial fibrillation. It is used when there is contraindication to anticoagulation or high risk of l...
Article

Waterston shunt

A Waterston shunt is a form of palliative surgery performed in patients with tetralogy of Fallot prior to the ability to repair the defect. It consists of a shunt formed between the ascending aorta and the right pulmonary artery. This does not relieve the right ventricular outflow obstruction, ...
Article

Wellens syndrome

Wellens syndrome (also referred to as LAD coronary T-wave syndrome) refers to a specific ECG abnormality in the precordial T-wave segment. It can be associated with a critical stenosis of the proximal left anterior descending artery.
Article

Wells criteria for pulmonary embolism

The Wells criteria for pulmonary embolism is a risk stratification score and clinical decision rule to estimate the probability for acute pulmonary embolism (PE) in patients in which history and examination suggests acute PE is a diagnostic possibility. It provides a pre-test probability which, ...
Article

Williams syndrome

Williams syndrome (WS) is characterised by some or all or the following features: craniofacial dysmorphism (e.g. elfin facies) oral abnormalities short stature (50% of cases) mild to moderate mental retardation supravalvular aortic stenosis 2 pulmonary artery stenosis 3 renal insufficienc...

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