Testicular germ cell tumours account for 90% of primary tumours of the testes. They are the most common nonhaematologic malignancy in men 15-49 years old.
They are divided into:
testicular seminoma: 40% of germ cell tumours 1
non-seminomatous germ cell tumour: 60% of germ cell tumours
Testicular leukaemia can be seen in patients during and after acute leukaemia. The blood-testis barrier limits chemotherapy from reaching the testicle, and therefore the testicle can act as a harbor for leukaemic cells.
Typically presents with painless testicular enlargem...
Testicular lipomatosis is a rare condition characterised by homogeneously hyperechoic non-shadowing lesions within the testes on ultrasound without flow on colour Doppler. It is seen as a component of PTEN (phosphatase and tensin homolog (gene)) hamartoma tumour syndrome which includes:
Testicular lymphoma is an uncommon testicular malignancy. Lymphoma can involve the testes in three ways:
primary site of extranodal disease (primary testicular lymphoma)
secondary involvement of systemic disease
primary manifestation of subclinical systemic disease
This article is concerned ...
Testicular microlithiasis (TM) is a relatively common condition that represents the deposition of multiple tiny calcifications throughout both testes.
The most common criterion for diagnosis is that of five microcalcifications in one testicle, although definitions have varied in the past. In t...
Testicular mixed germ cell tumours are, as the name suggests, testicular tumours composed of two or more types of germ cell tumour. They are considered to be part of non-seminomatous germ cell tumours, as it is that component which dictates prognosis and treatment.
Overall they account for ove...
Testicular sarcoidosis is a rare manifestation of sarcoidosis. In cases of urogenital sarcoidosis, more commonly the epididymis is affected.
Testicular sarcoidosis is more common in African-American patients, as are other forms of sarcoidosis 1. Up to 5% of patients with chronic s...
Testicular seminomas are the most common testicular tumours and account for ~45% of all primary testicular tumours. This article concerns itself only with testicular seminomas, however, seminomas can arise outside of the testicle most often within the anterior mediastinum, e.g. anterior mediasti...
Testicular teratoma, unlike ovarian teratoma, is often aggressive in its biological behaviour, and often exists as part of testicular mixed germ cell tumours.
Pure testicular teratomas account for only 4-9% of all testicular tumours. A similar number are seen in the context of t...
Testicular torsion occurs when a testicle torts on the spermatic cord resulting in the cutting off of blood supply. The most common symptom is acute testicular pain and the most common underlying cause, a bell-clapper deformity. The diagnosis is often made clinically but if it is in doubt, an ul...
Testicular trauma is the third most-common cause of acute scrotal pain and may result in various degree of damage to the testes.
Testicular rupture and testicular ischaemia/infarct are two severe complications which need to be ruled out. Other injuries that can occur include 1:
Testicular vasculitis can occur as either part of a systemic vasculitis or an isolated vasculitis involving only the testes with both having roughly equal prevalence.
The mean age of onset is approximately 40 years.
Symptoms can include a testicular mass w...
Testicular yolk sac tumours (also known as endodermal sinus tumour of the testis) is the most common childhood testicular tumour (80%), with most cases occurring before the age of two years 1. In adults, pure yolk sac tumour is extremely rare, however mixed germ cell tumour are commonly seen.
The testes, also known as the testicles, are the male gonads and are contained within the scrotum. The testes are responsible for the production of sperm and testosterone.
At birth, testes measure approximately 1.5 cm (length) x 1 cm (width), reaching ~4 mL volume at puberty 1.
Tethered spinal cord syndrome, also known as an occult spinal dysraphism sequence, is a neurological disorder caused by tissue attachments that limit the movement of the spinal cord within the spinal column.
The condition is closely linked to spina bifida, and as such pre...
Tetralogy of Fallot (TOF) is the overall most common cyanotic congenital heart condition with many cases presenting after the newborn period. It has been classically characterised by the combination of ventricular septal defect (VSD), right ventricular outflow tract obstruction (RVOTO), overridi...
A mnemonic for the underlying anatomic defects in tetralogy of Fallot is:
P: pulmonary stenosis
R: right ventricular hypertrophy
O: overriding aorta
V: ventricular septal defect
The thalamencephalon is an anatomic region that includes the thalamus, metathalamus and epithalamus. It is one of the components that form the diencephalon.
Thalamic haemorrhages or thalamic haemorrhagic strokes are often the result of chronic hypertension. The thalamus transmits or prevents transmission of sensory signals from sensory areas of the cerebral cortex through internal capsule fibres and has a role in memory thus the clinical presentatio...
Thalamostriate veins are formed by the joining of anterior caudate vein and the vein of stria terminalis. They join the septal veins and form internal cerebral veins.
The thalamostriate veins can be compressed in preterm neonates who have had germinal matrix haemorrhage. This...
The thalamus is the largest of the structures comprising the diencephalon.
The thalamus acts as a relay centre, receiving and distributing information between the peripheries and higher centres such as the cerebral cortices. It contributes to functions such as:
Thalassaemia is an autosomal recessive haemoglobinopathy that originated in the Mediterranean region. The genetic defect causes a reduction in the rate of globin chain synthesis which causes the formation of abnormal haemoglobin molecules. The resultant microcytic anaemia is the characteristic p...
Thalidomide embryopathy refers to a syndrome resulting from in utero exposure to thalidomide, and is characterized by multiple fetal anomalies. Fetal exposure to thalidomide occurred primarily from 1957 to 1961, when it was used as a treatment for nausea in pregnant women.
Thallium-201 chloride is a radiopharmaceutical used primarily in cardiac imaging.
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
Thanatophoric dysplasia (TD) is a lethal skeletal dysplasia. It is the most common lethal skeletal dysplasia followed by osteogenesis imperfecta type II.
The estimated incidence is around 1:25,000-50,000 3.
It results from a mutation coding for the fibroblas...
The air gap technique is a radiographic technique that improves image contrast resolution through reducing the amount of scattered radiation that reaches the image detector. In select situations, this technique can be used instead of an anti-scatter grid as the primary scatter reduction method i...
Theca lutein cysts (TLC), also known as hyperreactio luteinalis (HL), are a type of functional ovarian cysts. They are typically multiple and seen bilaterally.
They are thought to originate due to excessive amounts of circulating gonadotrophins such as beta-hCG. Hyperplasia of the th...
The four "Ds" of radiology reporting are the basic sequential tasks that a radiologist performs when reporting/reading a case, whether it be in training, the exam environment or in day-to-day clinical practice.
The 4 "Ds"
Diagnosis or differential diagnoses
In January 2012, we started sharing themed case collections with our facebook and twitter followers. These are a series of selected cases set on a particular subject which we think would be useful for residents, registrars to be familiar with. Below is a list of the case collections posted thus ...
The thenar eminence is the muscular bulge on the radial side of the palm due to the thenar muscles. They are innervated by median nerve, except FPB which also provided by ulnar nerve. Together the muscle group primarily acts to oppose the thumb. The four muscles are:
The thermal index (TI) is intended as a measure of an ultrasound beam's thermal bioeffects. It is often displayed on ultrasound screens (along with the mechanical index).
Absorption of sound waves may cause heating in tissue. The thermal index depends on:
a measure of time-averaged acoustic po...
Thermionic emission is the emission of electrons from a heated metal (cathode). This principle was first used in the Coolidge tube and then later in the modern day x-ray tubes. Before the discovery of the principle, gas tubes were used for x-ray production.
The cathode has its filament circuit ...
Thermoluminescent dosimeter (TLD) is a passive radiation detection device that is used for personal dose monitoring or to measure patient dose.
nickel-coated aluminium card with TLD discs
the discs are made of a thermoluminescent material, commonly calcium sulphate dope...
Thickening of bronchovascular bundles is a chest CT imaging feature that can be observed in a number of entities.
Conditions that can result in bronchovascular bundle thickening include:
sarcoidosis - see pulmonary manifestations of sarcoidosis 1
classical condition to giv...
Thiemann disease (also called familial osteoarthropathy of the fingers or osteonecrosis of the base of phalanx) is a non-inflammatory disorder of unknown aetiology and refers to osteonecrosis of the epiphyses of phalanges which leads to deformity of fingers.
Thiemann disease is a ...
Thigh refers to the portion of the lower limb between the hip and knee joints. Note that in an anatomical context "leg" refers to the portion between the knee and ankle joints and not to the entire lower limb.
Thimble bladder is a descriptive term for extreme fibrosis and contracture of the bladder walls, resulting in a tiny bladder. The term is usually used to describe changes from advanced genitourinary tuberculosis.
Third branchial cleft cysts are a very rare type of branchial cleft cysts. Although they are extremely rare, they remain the second most common congenital lesion of the posterior cervical region after cervical lymphatic malformations or cystic hygromas 3.
By definition, a t...
The third condyle (also known as condylus tertius or median occipital condyle) is a rare anatomic variant of the occipital condyles. It is a small separate ossicle at the anteromedial margin of the occipital condyle formed by the failure of the embryonic proatlas (4th occipital sclerotome) to un...
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...
The third occipital nerve (TON) is a branch of the posterior root of C3, which provides cutaneous sensation to a small portion of the occipital scalp.
Occipital region of the scalp close to the midline.
The posterior root of C3 (the third cervical nerve) gives...
The third ventricle is one of the four CSF-filled cavities that together comprise the ventricular system.
The third ventricle is a median cleft between the two thalami and is bounded laterally by them and the hypothalamus. Its anterior wall is formed by the lamina terminalis, and...
A third ventriculostomy is a type of surgical treatment for obstructive hydrocephalus, especially when obstruction is located at the level of the aqueduct of Sylvius (e.g. aqueduct stenosis). A permanent defect is created in the floor of the third ventricle anterior to the mammillary bodies, thu...
Thomas Edison (1847-1931) was a prolific inventor, considered by many to be the greatest inventor in American history. Edison holds around 1093 US patents; however, this article will focus on his work on fluoroscopy.
Early Life and career
Thomas Alva Edison was born on the 11th February 1897 ...
Thoracentesis, commonly known as a pleural tap or chest tap, is a procedure where excess pleural fluid is drained from the pleural space for diagnostic and/or therapeutic reasons. Ultrasound-guided thoracentesis performed by radiologists has been shown to have fewer complications than blind thor...
Thoracic actinomycosis refers to an uncommon indolent infection caused principally by the genus Actinomyces (higher prokaryotic bacteria belonging to the family Actinomyceataceae).
While it is rare in general, the thoracic form actinomycosis constitutes ∼15% of the total burden of...
Thoracic air leak syndrome (TALS) is an uncommon late complication in haematopoetic stem cell transplant recipients with chronic graft verses host disease. These patient led to develop features of thoracic air-leakage (i.e. spontaneous pneumomediastinum, spontaneous pneumothorax, pneumopericardi...
Thoracic anatomy encompasses the anatomy of all structures of the thoracic cavity.
This anatomy section promotes the use of the Terminologia Anatomica, the global standard for correct gross anatomical nomenclature.
The thoracic aorta is the most superior division of the aorta and is divided into three sections:
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 ...
Thoracic aortic aneurysms are relatively uncommon compared to abdominal aortic aneurysms. There is a wide range of causes, and the ascending aorta is most commonly affected. CTA and MRA are the modalities of choice to image this condition.
The normal aortic diameter varies based on...
There are a number of causes and mimics of thoracic aortic dilatation.
post-stenotic dilatation, e.g. bicuspid aortic valve
thoracic aortic aneurysm
atherosclerosis (usually descending thoracic aorta)
Thoracic aortic injury is the most common type of traumatic aortic injury and is a critical life-threatening, and often life ending event.
Approximately 80% of patients with thoracic aortic injury die at the scene of the trauma. In those who make it to hospital, clinical...
The differential for thoracic aortic stenosis includes:
aortitis (especially Takayasu arteritis)
Williams syndrome: supravalvular aortic stenosis
congenital rubella syndrome: supravalvular aortic stenosis
The thoracic cage refers to the skeleton of the thorax:
thoracic vertebral column
12 pairs of ribs
The thoracic duct is the main lymphatic channel for the return of chyle to the venous system. It drains lymph from both lower limbs, abdomen (except the convex area of the liver), left hemithorax, left upper limb and left face and neck.
The thoracic duct is the superior continua...
Pleural-thoracic empyema (commonly referred simply as an empyema) or pyothorax refers to an infected purulent and often loculated pleural effusion, and is a cause of a large unilateral pleural collection. It is a potentially life-threatening condition requiring prompt diagnosis and treatment.
Thoracic endometriosis is an uncommon location for endometriosis and the main cause of catamenial pneumothorax.
Most often occurs in the third and fourth decades of life 3.
Symptoms may include:
catamenial pleuritic chest pain
catamenial haemoptysis: whe...
Thoracic (or pulmonary) histoplasmosis refers to pulmonary manifestations from infection with the organism Histoplasma capsulatum which is an organism endemic to El Salvador but can be found widely in other parts of North, Central and South America. It can have variable clinical and radiographic...
High resolution CT (HRCT) of the lungs has specific terminology relating to pulmonary anatomy with which one needs to be comfortable.
secondary pulmonary lobule
interlobular septal thickening
Thoracic lymph nodes are divided into 14 stations as defined by the International Association for the Study of Lung Cancer (IASLC) 1, principally in the context of oncologic staging. For the purpose of prognostication, the stations may be grouped into 7 zones. The IASLC definitions leave some a...
Thoracic myelolipomas are extremely rare entities; only ~3% of myelolipomas are thought to occur in the thorax. When do occur in the thorax they can manifest as
mediastinal myelolipoma: most occur in the posterior mediastinum
intrapulmonary myelolipoma (much less common)
As with my...
Thoracic outlet syndrome (TOS) refers to a group of clinical syndromes caused by congenital or acquired compression of the brachial plexus or subclavian vessels as they pass through the superior thoracic aperture.
Clinical presentation will depend on the structure compre...
The thoracic plane, also known as the transthoracic plane or the plane of Ludwig is an artificial horizontal plane used to divide the mediastinum into the superior mediastinum and the inferior mediastinum.
It is defined as a horizontal line that runs from the manubriosternal joint (sternal angl...
A handy mnemonic to remember the structures found at the level of the thoracic plane (also known as the plane of Ludwig) is:
C: cardiac plexus
L: ligamentum arteriosum
A: aortic arch (inner concavity)
P: pulmonary trunk
T: tracheal bifurcation (carin...
The thoracic spine forms the middle part of the vertebral column. It extends from below C7 on the cervical spine to above L1 on the lumbar spine. There are 12 thoracic vertebra, termed T1-T12 (some older doctors and texts refer to the dorsal spine and D1-D12).
The thoracic spine is unique due ...
The thoracic spine AP view images the thoracic spine, which consists of twelve vertebrae. It is utilised in many imaging contexts including trauma, postoperatively, and for chronic conditions.
the patient is erect or supine, depending on clinical history
ideally, spinal imag...
The thoracic spine lateral view images the thoracic spine, which consists of twelve vertebrae. It is utilised in many imaging contexts including trauma, postoperatively, and for chronic conditions. It is used in conjunction with the thoracic spine AP view to complete a thoracic spine series.
The thoracic spine series is comprised of two standard projections along with a range of additional projections depending on clinical indications. The series is often utilised in the context of trauma, postoperative imaging and for chronic conditions.
Radiographs of the thoracic spine are consi...
The thoracic spine sign on lung ultrasound is an indirect indicator of the presence of a pleural effusion or haemothorax. It represents the visualisation of the vertebral bodies in the thoracic cavity above the diaphragm which are usually not seen unless there is a fluid collection.
Thoracic splenosis refers to autotransplantation of splenic tissue into the pleural space which typically occurs after trauma. It may occur in approximately 18% of patients with combined diaphragmatic and splenic injuries and is more common after penetrating injuries.
Splenic tissue ...
Thoracoabdominal sign, a variation of the silhouette sign, is a frontal chest radiograph sign which helps to localize a thoracic lesion.
Since the posterior costophrenic sulcus is more caudal than the anterior lung, a thoracic lesion must be posterior if its caudal end is visible below the dome...
The thoracoacromial artery is a vessel arising from the axillary artery at the axilla.
origin: first branch of the second part of the axillary artery 1
supply: pectoralis major and minor, anterior part of the deltoid, and dermal sensation overlying the clavipectoral ...
A useful mnemonic to remember the branches of the thoracoacromial artery is:
The thoracodorsal nerve also known as the middle subscapular or long subscapular nerve arises from the posterior cord of the brachial plexus and supplies the latissimus dorsi muscle.
The thoracodorsal nerve arises from the posterior cord of the brachial plexus with fibres...
The thoracoepigastric vein provides a communication between the superficial epigastric vein and the lateral thoracic vein as it ascends superficially on anterolateral chest and abdominal wall. It, therefore, drains into both the superior vena cava via the axillary vein and the inferior vena cava...
Thoracoliths are rare, calcified pleural-based nodules that are almost always incidental findings. They are usually considered mobile, and more common on the left.
The exact aetiology is unknown and theories include 1,2:
calcified fibrin body
degenerated pleural lipoma
The thoracolumbar injury classification and severity score (TLICS), also sometimes known as the thoracolumbar injury severity score (TISS), was developed by the Spine Trauma Group in 2005 to overcome some of the perceived difficulties regarding the use of other thoracolumbar spinal fracture clas...
The two most commonly currently used thoracolumbar spinal fracture classification systems are the AO classification and the TLICS although a number of other classification systems have been proposed over the years 1. Each has benefits and drawbacks and each incorporates various features in an at...
Thoracopagus conjoined twins are, as the name suggests, conjoined twins united at their thorax.
Fusion is typically face-to-face, at the upper thorax to the umbilicus with a common sternum, diaphragm, and upper abdominal wall. Very often a common pericardial sac is present as well as a degree o...
Thoracoplasty is a surgical procedure that was originally designed to permanently collapse the cavities of pulmonary tuberculosis by removing the ribs from the chest wall 1-3 . The resection of multiple ribs, allows the apposition of parietal to the visceral or mediastinal pleura. Until supplant...
Thorotrast is a suspension of radioactive thorium dioxide first produced in Germany in 1928 and used as a contrast agent until the 1950s. Its principal use was for cerebral angiography: 90% of the estimated 50,000-100,000 patients treated received it for this purpose.
The threads and streaks sign refers to an angiographic appearance of a vascularised tumour thrombus extending into the ipsilateral renal vein or the inferior vena cava from a renal cell carcinoma. This gives an appearance of linear, thread-like or string-like appearance of the involved vessel.
Threatened miscarriage (or threatened abortion) is mainly a clinical term, used when a pregnant woman in first 20 weeks of gestation presents with spotting, mild abdominal pain and contractions, with a closed cervical os.
It occurs in 20-25% of pregnancies and is associated with ...
The three column concept of thoracolumbar spinal fractures was initially devised by Francis Denis and presently CT is mandatory for an accurate classification.
While initially developed for classification of thoracolumbar spinal fractures, it can also be applied to the lower cervical spine 3 as...
The three line sign refers to an MRI term that describes the appearance of roundworm Ascaris lumbricoides within the CBD lumen which appears as two hypointense lines representing the worm walls and hyperintense centre which represents the worm gut.
The three vessel and trachea view (or 3VT view) is one of the fetal echocardiography views. In this view, aortic and ductal arches are combined into the DAo and appear as a V-shaped confluence. Both arches tend to be of similar size and are located towards the left of the trachea. The thymus is ...
Throckmorton sign, also known as John Thomas sign, refers to when the penis points in the direction of unilateral disease, typically of the pelvis or hip.
Throckmorton sign is a slang term used humorously by medical students and residents.
According to the first serious study of the sign publ...
Thrombocytopenia with absent radius (TAR) syndrome is primarily characterised by the following two features:
absent fetal radii (bilaterally) with the presence of both thumbs
The condition is extremely rare with an estimated incidence of 0.4 per 100,000 bi...
The thrombolysis in cerebral infarction (TICI) grading system was described in 2003 by Higashida et al. 1 as a tool for determining the response of thrombolytic therapy for ischaemic stroke. In neurointerventional radiology it is commonly used for patients post endovascular revascularisation. Li...
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...
Thrombotic thrombocytopaenic purpura (TTP) is a rare but life-threatening condition characterised by thrombocytopaenia, microangiopathic haemolytic anaemia and end-organ damage.
The prevalence of TTP is ten cases per one million people 2. Ninety-percent of cases occur in adulthood...
Thrombus fissuration is a sign of impending rupture of an aortic aneurysm. It reflects blood dissecting into the intramural thrombus. This sign is observed on contrast-enhanced CT as linear contrast infiltrations from the aneurysm lumen through the intramural thrombus. Thrombus fissurations exte...
The thumb AP (anteroposterior) view is one of the standard views for assessment of the thumb. The PA (posteroanterior) view can be utilised when the patient is unable to achieve the position required for the AP view. They are one part of the three view thumb series.
There will be some magnific...