Testicular mixed germ cell tumors are, as the name suggests, testicular tumors composed of two or more types of germ cell tumor. They are considered to be part of non-seminomatous germ cell tumors, as it is that component which dictates prognosis and treatment.
Overall they account for over 10...
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 tumors and account for ~45% of all primary testicular tumors. 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 mediastina...
Testicular teratoma, unlike ovarian teratoma, is often aggressive in its biological behavior, and often exists as part of testicular mixed germ cell tumors.
Pure testicular teratomas account for only 4-9% of all testicular tumors. A similar number are seen in the context of test...
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 ischemia/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 tumors (also known as endodermal sinus tumor of the testis) is the most common childhood testicular tumor (80%), with most cases occurring before the age of two years 1. In adults, pure yolk sac tumor is extremely rare, however mixed germ cell tumor are commonly seen.
The testes (singular: testis), 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 vol...
Tethered cord syndrome is a neurological disorder caused by tissue attachments that limit the movement of the spinal cord within the spinal canal.
Tethered cord syndrome is a clinical diagnosis based on neurologic deterioration involving the lower spinal cord 7. Patients ...
Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart condition with many cases presenting after the newborn period. It has been classically characterized by the combination of ventricular septal defect (VSD), right ventricular outflow tract obstruction (RVOTO), overriding aorta...
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
Texture analysis is a non-invasive, mathematical method assessing the spatial heterogeneity of regions of interest in medical imaging, its primary application is in the assessment of tumors. Although not a new topic of research, the past decade has seen a significant resurgence of texture analys...
The thalamencephalon is an anatomic region that includes the thalamus, metathalamus and epithalamus. It is one of the components that form the diencephalon.
Thalamic hemorrhages or thalamic hemorrhagic 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 fibers and has a role in memory thus the clinical presentation ...
Thalamic infarcts refer to ischemic strokes which affect the subcortical grey matter complex of nuclei known as the thalamus.
Pure thalamic infarcts are reported to make up 3-4% of cerebral ischemic events 1.
Most of the risk factors are common to all types of isch...
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 hemorrhage. This ...
The thalamus (plural: thalami) is the largest of the structures comprising the diencephalon.
The thalamus acts as a relay center, receiving and distributing information between the peripheries and higher centers such as the cerebral cortices. It contributes to functions such as:
Thalassemia is an autosomal recessive hemoglobinopathy 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 hemoglobin molecules. The resultant microcytic anemia is the characteristic prese...
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.
Thalidomide-induced pneumonitis is a rare from of drug-induced lung disease. It could be suspected in patients who develop dyspnea, cough, and fever after taking thalidomide, without a definite cause, with chest radiographs +/- CT shows supportive findings. Many publications suggest this is reve...
Thallium-201 (Th-201) is a radiopharmaceutical used for scintigraphy, primarily of the myocardium. The element thallium is treated by the body as an analog of potassium; it is produced in a cyclotron by bombarding thallium-203 with protons.
thallium is a monovalent cation
Thanatophoric dysplasia 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 fibroblast gro...
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 Pre-Conception and Pre-Natal Diagnostic Techniques (Prohibition Of Sex Selection) Act (PCPNDT) is a statute enacted to stop the female feticide that has resulted in declining female sex ratio in India.
As per census 2011, adult sex ratio in India is 943 females per 1000 males and child sex...
Therapy-related myeloid leukaemias, also referred to as therapy-related myeloid neoplasms, occur as a late complication after cytotoxic therapies (e.g. chemotherapy, immunosuppressive therapy, and radiation therapy) performed to treat other conditions. They represent hematological malignancies w...
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 p...
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 aluminum card with TLD discs
the discs are made of a thermoluminescent material, commonly calcium sulphate doped...
The Thessaly test is a clinical examination technique useful in the detection of meniscal tears.
Meniscal tears are commonly the result of twisting injuries or degenerative change where patients experience medial or lateral joint line pain. MRI is the most commonly used non-invasive...
Thiamine deficiency is caused by a low level of thiamine (vitamin B1) in the body, and when severe, a deficiency may manifest in adults as beriberi.There are two main forms:
wet beriberi: high-output cardiac failure predominates
Shoshin beriberi 3: severe acute wet form with high mortality
Thickening of bronchovascular bundles is a chest CT imaging feature that can be observed in a number of entities. It has some overlap with the terms peribronchovascular interstitial thickening and peribronchovascular thickening.
Conditions that can result in bronchovascular b...
Thiemann disease (also called familial osteoarthropathy of the fingers or osteonecrosis of the base of phalanx) is a non-inflammatory disorder of unknown etiology and refers to osteonecrosis of the epiphyses of the phalanges which leads to deformity of the fingers.
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.
The thin postcentral gyrus sign is an anatomic landmark useful for identifying the central sulcus on cross-sectional imaging.
The anteroposterior dimension of the postcentral gyrus surface is less than that of the precentral gyrus surface, as seen in the axial or sagittal planes. Identifying tw...
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.
Third branchial cleft cysts ...
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...
Third inflow refers to anatomical variants leading to an additional venous inflow to the liver apart from the usual dual blood supply (portal vein and hepatic artery). They tend to be associated with parenchymal pseudolesions (focal hyperenhancement on post-contrast imaging, focal fat infiltrati...
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 anteriorly and the hypothalamus and subthalamus posteriorly. Its anterior wall ...
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 over one thousand US patents; however, this article will focus on his work on fluoroscopy.
Early life and career
Thomas Alva Edison was born on 11 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 allogeneic haematopoetic stem cell transplant recipients with chronic graft versus host disease. Thoracic air leakage refers to spontaneous pneumomediastinum, pneumothorax, pneumopericardium, and/or interstitial emphysema. The...
Thoracic amyloidosis can have different manifestations depending on the specific anatomic site:
nodular parenchymal amyloidosis
diffuse parenchymal amyloidosis
Thoracic anatomy encompasses the anatomy of all structures of the thorax.
This anatomy section promotes the use of the Terminologia Anatomica, the international standard of 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 third intercostal space. It term...
Thoracic aortic aneurysms are relatively uncommon compared to abdominal aortic aneurysms. There is a wide range of causes, and the ascending aorta is the segment most commonly affected. Both CTA and MRA are the modalities of choice to image this condition.
The normal aortic diamete...
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 vessel for the return of chyle/lymph to the systemic 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 supe...
Thoracic duct embolization (TDE) is a safe, efficacious treatment for chylothorax 1. Chylothoraces with a low drain output (<1L/day) are traditionally managed conservatively with dietary change, while high output (>1L/d) are managed with surgical thoracic duct (TD) ligation 2.Thoracic duct embo...
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 hemoptysis: when...
A thoracic endovascular aneurysm repair (TEVAR) is a type of endovascular aneurysm repair that involves the thoracic aorta.
It is a commonly applied treatment strategy for the a various thoracic aortic pathologies inclusive of both
type A and type B thoracic aortic dissections
Thoracic (or pulmonary) histoplasmosis refers to pulmonary manifestations from infection with the organism Histoplasma capsulatum which is an organism endemic to the Central American state of El Salvador but can be found widely in other parts of both North and South America. It can have variable...
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)
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...
Thoracic pleomorphic adenoma can include
pleomorphic adenoma which has metastased to the lungs
primary pulmonary pleomorphic adenoma - extremely rare 1
primary pleomorphic adenoma of bronchial/tracheal origin - extremely rare 4,5
Thoracic sarcoidosis can be staged on a chest radiograph with implications for prognosis although HRCT and FDG-PET provide more information to help guide treatment.
Chest radiographs have been the mainstay of staging thoracic sarcoidosis for many decades with fair interobserver concord...
The thoracic spine (often shortened to T-spine) forms the middle part of the vertebral column. It extends from below C7 of the cervical spine to above L1 of the lumbar spine. There are 12 thoracic vertebra, termed T1-T12.
The thoracic spine is unique due to its articulation with ribs via costal...
The thoracic spine AP view images the thoracic spine, which consists of twelve vertebrae. It is utilized in many imaging contexts including trauma, postoperatively, and for chronic conditions.
the patient is erect or supine, depending on clinical history
ideally, spinal imag...
Thoracic spine fracture-dislocations are severe forms of spinal column injuries that occur secondary to high-energy trauma, in which there is vertebral fracture concomitant with dislocation of facet joints and/or the intervertebral disc space. They are mechanically unstable and are associated wi...
The thoracic spine lateral view images the thoracic spine, which consists of twelve vertebrae. It is utilized 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 checklist is just one of the many pathology checklists that can be used when reporting to ensure that you always actively exclude pathology that is commonly missed; this is particularly helpful in the examination setting, e.g. the FRCR 2B rapid-reporting.
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 utilized in the context of trauma, postoperative imaging and for chronic conditions.
Radiographs of the thoracic spine are consi...
The thoracic spine sign, or spine sign, on lung ultrasound is an indirect indicator of the presence of a pleural effusion or hemothorax. It represents the visualization of the vertebral bodies in the thoracic cavity above the diaphragm which are usually not seen unless there is a fluid collectio...
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 fibers...
The thoracoepigastric vein provides a communication between the superficial epigastric vein and the lateral thoracic vein as it ascends superficially on the anterolateral chest and abdominal wall. It, therefore, drains into both the superior vena cava via the axillary vein and the inferior vena ...
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 etiology 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...
Thoracolumbar spinal fracture classification systems are numerous and represent attempts by various authors to create systems that allow uniform and reproducible classification and description of thoracolumbar fractures which in turn can help with treatment decision making and prognostication.
Thoracolumbar spine fractures are often the result of significant blunt trauma such as motor vehicle accidents or falling from a height. Fractures in this region range from non-complex to highly complex and will vary in prognosis.
Males are affected more commonly than females wit...
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 . It involved resection of multiple ribs, allowed the apposition of parietal to the visceral or mediastinal pleura. Until...
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. Umbrathor was another thori...
The threads and streaks sign refers to an angiographic appearance of a vascularized tumor 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.