Splenic epithelial cysts, also referred as splenic epidermoid cysts or primary splenic cysts, are unilocular fluid lesions with thin and smooth walls and no enhancement. They represent ~20% of cysts found in the spleen, and are usually an innocuous incidental imaging finding.
Note that most (~8...
Splenic haemangiomatosis involves multiple, diffuse splenic hemangiomas replacing its entire parenchyma. It is a very rare entity.
It can occur as a manifestation of systemic angiomatosis or, less commonly, confined to the spleen (diffuse isolated splenic haemangiomatosis). There is ...
There are a number of splenic lesions and anomalies:
Benign mass lesions
splenic cyst (mnemonic)
splenic hemangioma: commonest benign spl...
Splenic pseudocysts, also referred as secondary splenic cysts, are acquired cystic lesions not delineated by a true epithelial wall. They represent the majority of the splenic cystic lesions, corresponding to approximately 80% of them (c.f. splenic epithelial cysts). The main causes are:
Splenomegaly refers to enlargement of the spleen. The upper limit of normal adult splenic length is traditionally cited at 12 cm, but lengths upwards of 14 cm can be seen in normal, taller males 7.
Massive splenomegaly is variably defined, including when the spleen is 5 standard deviations abov...
Spontaneous nipple discharge in a non lactating breast can result from many causes which include:
papillary lesions of breast: present in ~35-50% of cases with spontaneous nipple discharge
mammary duct ectasia
ductal carcinoma in situ: 5-21%
Spontaneous splenic rupture (SSR) (or atraumatic splenic rupture) is rare, especially when compared to traumatic splenic rupture.
The pathogenesis of atraumatic splenic rupture is not well understood. Splenomegaly is present in almost all patients (~95%), although rupture of normal ...
Cricket is a popular game in Commonwealth countries. Sports injuries in this game can be associated with three positional aspects of the game: bowling, batting or fielding. Radiologists should know the different kind of injuries related to this game for a better clinical association. Injuries ca...
Overhead elbow sports injuries are a group of pathologies seen in sports activities with overhead throwing or strokes, e.g. tennis, volleyball, baseball, javelin throwing. There has been a tremendous increase in the number of participants in these sports activities worldwide.
Snowsport injuries cover a broad range of activities from alpine or Nordic skiing, snowboarding, and recreational play (e.g. tobogganing, tubing).
Snowsports are popular with over 70 million people globally participating each year 1. While the injury rate varies depending on loca...
Sprue is the collective term for the malabsorptive gastrointestinal enteropathies although it may be used to refer directly to tropical sprue. It is composed of two entities:
non-tropical sprue / celiac disease
In each, the radiologic features are not sensitive enough to confir...
Storage disorders comprise a bewildering collection of inherited metabolic conditions which share the accumulation of a metabolite within various cells in the body due to dysfunction of specific enzymes or transport proteins. Accumulation of metabolites eventually results in cellular and/or orga...
Brain ischemia/infarction in children and young adults can result from several causes.
cyanotic heart disease
mitral valve prolapse
Subacromial impingement is by far the most common form of shoulder impingement and occurs secondary to attrition between the coracoacromial arch and the underlying supraspinatus tendon or subacromial bursa, leading to tendinopathy and bursitis respectively.
There are a wide range of causes for subarachnoid FLAIR hyperintensity, both pathological and artifactual.
FLAIR vascular hyperintensities in acute stroke 1,4,8
A subcutaneous abscess is a manifestation of a spectrum of soft tissue skin infection which includes cellulitis and necrotizing fasciitis. It is a form of abscess which lies within the dermis and subdermal cutaneous layers. Along with dental abscesses, subcutaneous abscesses are the most common ...
Subcutaneous calcification can be associated with a number of disorders. The list includes:
basal cell nevus syndrome
as a manifestation of systemic lupus erythematosus
Subdiaphragmatic free gas is one of the ways of detecting presence of free intraperitoneal gas (i.e. pneumoperitoneum). It is the presence of free, extraluminal gas in the anterior subhepatic space.
Subdiaphragmatic free gas is well appreciated as the g...
Subluxed facet joint is the mildest form of facet dislocation in which the ligamentous injury leads to partial uncovering of facet joint (c.f. complete uncovering in perched facet). This results in mild anterior displacement of one vertebral body on another (anterolisthesis).
Subperiosteal bone resorption is the most consistent and specific finding of hyperparathyroidism and is virtually pathognomonic of the condition.
While the terminal tufts of the phalanges are the most commonly involved bones, many others are involved:
tufts of the distal...
Subpulmonic effusions (also known as subpulmonary effusions) are pleural effusions that can be seen only on an erect projection. Rather than layering laterally and blunting the costophrenic angle, the pleural fluid lies almost exclusively between the lung base and the diaphragm.
Sunburst or sunray appearance describes two separate findings in the bone: a periosteal reaction and a trabeculation pattern. It should not be confused with the sunburst sign of meningioma vascularity.
Sunburst periosteal reaction reflects aggressive periostitis. The sunburst appearance occurs...
Superficial siderosis is a rare condition which results from the deposition of hemosiderin along the leptomeninges, with eventual neurological dysfunction.
On imaging, it is classically characterized on MRI as a rim of low signal coating the surface of the brain or spinal cord, particularly not...
Superficial thrombophlebitis, also called superficial venous thrombosis (SVT), is a pathological condition characterized by the presence of a thrombus in the lumen of a superficial vein, accompanied by inflammatory reaction of adjacent tissues.
Some authors, however, reserve the te...
Supernumerary ribs occur most commonly as a cervical rib arising from C7 or a lumbar rib arising from L1. In extremely rare situations, there can be sacral, coccygeal, intrathoracic, or aberrant lumbar ribs 3. Rarely supernumerary ribs (cervical and lumbar ribs aside) have been found as 'normal'...
Superscan is intense symmetric activity in the bones with diminished renal and soft tissue activity on a Tc99m diphosphonate bone scan.
This appearance can result from a range of etiological factors:
diffuse metastatic disease
transitional cell c...
The differential for suprasellar cystic lesions is large and predominantly includes developmental and neoplastic conditions.
Rathke's cleft cyst
enlarged perivascular spaces...
A surgical sieve is an approach to differential diagnosis that prompts the user to consider various types of pathologies systematically. A surgical sieve does not need to be a mnemonic 2, although many find it easier to remember it when a mnemonic is used. Various versions of this mnemonic exist...
Suspected physical abuse (SPA), also known as non-accidental injury (NAI) or inflicted injury, in infants and young children represents both ethical and legal challenges to treating physicians.
Radiologists may be the first clinical staff to suspect non-accidental injuries when confronted with ...
Suspicious breast calcifications are calcifications within the breast that have a morphology and/or distribution on mammography indicating a significant probability of malignancy. These merit further workup and biopsy 1.
Some calcifications may be more conspicu...
Swan neck deformity is a musculoskeletal manifestation of rheumatoid arthritis presenting in a digit, with the combination of:
hyperextension of a proximal interphalangeal (PIP) joint
flexion of a distal interphalangeal (DIP) joint
The swan neck deformity characterized by hyperexte...
There are a large number of causes for a symmetrical periosteal reaction 1,2:
chronic venous insufficiency
physiologic periostitis, most common cause before 6 months old
juvenile idiopathic arthritis
Syndactyly (plural: syndactylies) refers to a congenital fusion of two or more digits. It may be confined to soft tissue (soft tissue syndactyly/simple syndactyly) or may involve bone (bony syndactyly/complex syndactyly).
The overall estimated incidence is at ~1 per 2,500 to 5,000...
Syndesmophytes are calcifications or heterotopic ossifications inside a spinal ligament or of the annulus fibrosus. They are seen in only a limited number of conditions including:
They can be classified as...
Syringobulbia is a rare entity and refers to a syrinx that extends into the medulla oblongata 1.
Some authors use syringobulbia to refer to a syrinx present in any portion of the brainstem rather than specifically involving the medulla oblongata, and therefore encompassing syringop...
Syrinx (pl. syringes) is the collective name given to hydromyelia, syringomyelia, syringobulbia, syringopontia, syringomesencephaly, and syringocephalus.
The use of the general term 'syrinx' has grown out of the difficulty in distinguishing between hydromyelia and syringomyelia usi...
Talar body fractures are a subtype of talar fracture, subdivided into:
talar dome osteochondral fracture
posterior talar process fracture
lateral talar process fracture
There are many types of talar dislocation given its multiple articulations:
total talar dislocation
Talar fractures are an uncommon injury, accounting for <5% of all foot fractures. Recognition of the unique talar anatomy is important for correct diagnosis.
talar head fractures
talar neck fractures
talar body fractures
talar dome osteochondral fracture
Telecanthus (rare plural: telecanthi) represents an increased intercanthal distance. It is often used interchangeably with hypertelorism, referring to increased distance between the eyes.
Causes and associations
trauma: naso-orbito-ethmoidal (NOE) fractures
Destructive lesions of the temporal bone (petrous pyramid, middle ear and antrum) have a relatively broad differential including 1:
lesions affecting petrous pyramid
vestibular schwannoma (acoustic neuroma)
neuroma of trigeminal and facial nerve
glomus jugulare ...
Temporomandibular joint (TMJ) effusions are unusual in asymptomatic patients, and thus should trigger a careful search for underlying pathology. It usually precedes osteoarthritis of the TMJ. Effusions are seen in:
rheumatoid arthritis (RA)
Tension pneumothoraces occur when intrapleural air accumulates progressively in such a way as to exert positive pressure on mediastinal and intrathoracic structures. It is a life-threatening occurrence requiring both rapid recognition and prompt treatment to avoid a cardiorespiratory arrest.
The differential diagnosis for a terminal ileitis is quite extensive, and includes:
inflammatory bowel disease
Crohn disease (most common)
backwash ileitis due to ulcerative colitis
There is only a short list of terminal tuft masses, which can arise from the adjacent soft tissues and erode the terminal tuft as well as arising from the terminal tuft itself:
epidermal inclusion cyst: history of penetrating trauma
tenosynovial giant cell tumor: occur laterally
The terminal zones of myelination are located at the posterior aspect of the lateral ventricles (the peritrigonal regions) and are the only part of the cerebral white matter that may exhibit high T2 signal in a normal brain at 2 years of age, when myelination of cerebral white matter normally be...
Testicular cancers are the most common neoplasm in men between the ages of 20 and 34 years.
Testicular cancer is uncommon, accounting for less than 1% of all internal organ malignancies 2.
The demographics of affected individuals depends on the age of the histology of the tumor. ...
Testicular microlithiasis is a relatively uncommon 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 the ...
Testicular trauma is the third most-common cause of acute scrotal pain and may result in various degrees 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:
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
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...
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)
The differential for thoracic aortic stenosis includes:
aortitis (especially Takayasu arteritis)
Williams syndrome: supravalvular aortic stenosis
congenital rubella syndrome: supravalvular aortic stenosis
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 3.
It occurs in 20-25% of pregnancies and is associated with...
A number of inflammatory conditions can affect the thyroid gland, each commonly described as thyroiditis (plural: thyroiditides):
acute suppurative thyroiditis (AST)
subacute lymphocytic thyroiditis (a.k.a. silent thyroiditis or painless subacute th...
Thyroid malignancies are most commonly primary thyroid cancers but can rarely be metastatic deposits.
Thyroid malignancies can be categorized into the following key subtypes:
primary thyroid cancers
papillary thyroid carcinoma: 60-80% of carcinomas
Tibiotalar slant is the superolateral inclination of the tibial plafond, and results in an ankle valgus deformity. There are a number of causes 1:
trauma, i.e. distal tibial fractures
osteomyelitis and/or septic arthritis
juvenile idiopathic arthritis
sickle cell dis...
Tonsillar herniation is a type of brain herniation characterized by the inferior descent of the cerebellar tonsils below the foramen magnum >3mm 5. Clinically, the presence of tonsillar herniation is often called coning.
The terminology of caudally displaced tonsils is discussed in the article ...
Tonsillitis refers to inflammation of any of the tonsils and is one of the most common head and neck infections in adolescents and young adults.
Patients may present with a variety of symptoms including painful throat (may be unilateral), dysphagia, fevers, tender cervica...
Torsion in bone refers to as the rotation or contortion along the longitudinal axis of the bone.
The long bones, particularly the femur, humerus and tibia are most commonly affected and torsional abnormalities can be developmental or posttraumatic in nature or can arise from overuse 1.
Torticollis (wryneck) is a clinical finding of head tilt with or without rotational spinal malalignment. It is not a diagnosis in itself and there are a wide range of underlying conditions. It is most common in the pediatric age group.
Torticollis can be acute (<1 week) or chronic (...
Total hip arthroplasty (THA) or total hip replacement (THR) is an orthopedic procedure that involves the surgical excision of the femoral head and cartilage of the acetabulum and replacement of the joint with articulating femoral and acetabular components. It is a commonly performed procedure us...
Toxoplasmosis and lymphoma are frequently differential diagnoses in patients with HIV/AIDS, as these represent the most common brain lesions with mass effect in this population. As treatment is substantially different, distinguishing the two on imaging is important, particularly when the lesion ...
Primary tracheal and endobronchial lesions are generally rare and can be either malignant or benign. The majority of these lesions are malignant.
primary malignant endobronchial lesions
squamous cell carcinoma: commonest malignant lesion in th...
Tracheal buckling is a normal finding in young infants when it is more flexible. There is typically deviation of the trachea anteriorly and to the right (up to 90°) and any other configuration (i.e. to the left or posteriorly) should raise the possibility of underlying pathology.
The differential for tracheal masses can be rather wide.
For a single mass consider:
direct invasion from adjacent organ (lung, thyroid, esophagus and larynx)
distant metastasis (e.g. melanoma, breast, renal, and colon cancer)
squamous cell carcinoma: commone...
Tracheal wall thickening may have several causes. For diagnostic purposes, tracheal thickening may be categorized by length of airway involvement in order to narrow the differential diagnoses. Note that some etiologies may be associated with either focal or diffuse pattern of involvement.
Traction bronchiectasis refers to an etiological subtype of bronchiectasis where there is irreversible dilatation of bronchi and bronchioles within areas of pulmonary fibrosis or distorted lung parenchymal architecture.
It can arise from a number of underlying causes which result in ...
Transalar (transsphenoidal) herniation describes herniation of brain matter in and around the middle cranial fossa across the greater sphenoid wing and can be ascending or descending. Compression of structures against the sphenoid bone results in symptoms.
Transalar herniation is not...
Transient arterial phase respiratory motion-related artifact refers to common self-limited dyspnea observed immediately after the administration of gadoxetate disodium during liver MRI studies. The physiopathology behind this phenomenon is poorly understood and its incidence varies among differe...
Transient hepatic attenuation differences (THAD) lesions refer to areas of parenchymal enhancement visible during the hepatic artery phase on helical CT. They are thought to be a physiological phenomenon caused by the dual hepatic blood supply. Occasionally, they may be associated with hepatic t...
Transitional aneurysms, also referred to as transitional paraclinoid aneurysms, are saccular cerebral aneurysms arising from the clinoid-ophthalmic segment of the internal carotid artery (ICA) and near the distal dural ring with potential risk for subarachnoid hemorrhage.
After an anterior turn...
Transtentorial herniation is a type of cerebral herniation broadly divided into two major types based on the direction of herniation: downwards due to supratentorial mass effect and upward due to infratentorial mass effect.
Downward transtentorial herniation
Downward herniation occurs when the...
Trapped lung, also known as unexpandable/unexpanded lung, is a term used where there is non-expandable lung after fluid removal, often thoracentesis. It is similar to but not entirely synonymous with the term lung entrapment, which is a similar condition caused by active pleural disease rather t...
Trauma is a leading cause of mortality in pregnancy. Pregnancy increases the incidence and severity of abdominal trauma in females.
Trauma affects up to 7% of pregnancies, and the incidence of pregnancy in level 1 trauma patients is estimated to be ~2% 1.
Traumatic spinal cord injury can manifest as a wide variety of clinical syndromes resulting from damage to the spinal cord or its surrounding structures. It can result from minor injury if the spine is weakened from disease such as ankylosing spondylitis or if there is pre-existing spinal stenos...
Triphalangeal thumb is considered a form of pre-axial polydactyly.
Triphalangeal thumbs have an incidence of 1 in 25,000 7.
A triphalangeal thumb, as the name implies, has three phalanges instead of the usual two. There is an autosomal dominant genetic transmission 8,...
Troponin is a protein of key importance in the functioning of skeletal and cardiac muscle. It forms part of the contractile mechanism, and comprises three main subunits: troponin C, troponin I, and troponin T.
Elevation of serum troponin can occur from a number of causes an...
Tuberculosis of the central nervous system can result from either hematogenous spread from distant systemic infection (e.g. pulmonary tuberculosis) or direct extension from local infection (e.g. tuberculous otomastoiditis).
Intracranial manifestations of tuberculosis are protean and can affect ...
Tubulinopathies refer to a wide spectrum of cortical malformations that result from defects in genes encoding the tubulin protein that regulates neuronal migration during brain development.
Some series report a high prevalence of seizures during infancy which may the init...
Tumor ablation, or image-guided tumor ablation, is the direct application of chemical or energy-based (i.e. thermal and nonthermal) treatments to cause local tumor destruction. Techniques include:
radiofrequency ablation (RFA)
microwave ablation (MWA)...
There are a number of tumors of muscular origin, which overall are relatively uncommon, representing ~2% of benign soft tissue tumors and ~10% of malignant soft tissue tumors 1.
The tumors can be divided according to the type of muscle fiber:
Skeletal muscle origin
Tumors of the chest wall are varied, some of which are found most often in this region. They can be divided into benign and malignant tumors and into those which arise in the ribcage and those of soft tissue density.
Benign tumors include 1,3,4:
Tumors of the male urethra are uncommon. They can be categorized both on the grounds of histology and location.
squamous cell carcinoma of the urethra: 80%
urothelial/transitional cell carcinoma of the urethra: 15% (predominantly posterior urethra)
adenocarcinoma of the urethra: 5%...
The small intestine is rarely the site of malignant tumors, although it accounts for ~75% of the entire length of the GI tract and more than 90% of the mucosal surface. Approximately 40 different histologic tumor types have been described.
In this article, an overview will be given of the most...
Tumors that metastasize to bone may be remembered using the mnemonic "lead kettle" spelled PBKTL (lead is Pb on the Periodic Table).
For females, breast and lung are the most common primary sites; nearly 80% of cancers th...
Twin pregnancies are the most common multifetal pregnancies.
Multifetal pregnancies account for ~1% of all pregnancies but are seen in much higher numbers in populations where in vitro fertilisation (IVF) is a common practice.
A twin pregnancy can be broadly cate...
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 projec...
Ultrasound appearance of liver metastases can have bewildering variation, and the presence of hepatic steatosis can affect the sonographic appearance of liver lesions.
Patterns do exist between ultrasound appearance of the liver metastases and the likely prima...
Umbilical cord cysts can refer to any cystic lesion associated with the umbilical cord. They can be single (commoner) or multiple.
They may be seen in ~3% of pregnancies in the first trimester 8.
Umbilical cord cysts can represent either true or false cysts:
Unilateral axillary lymphadenopathy while being more concerning than bilateral axillary lymphadenopathy can still arise from a variety of benign, as well as malignant, causes.
other regional infective causes
ipsilateral arm infection, e.g. cellulitis
Unilateral facet dislocation is a relatively stable type of facet dislocation.
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...
Unilateral pulmonary edema represents only 2% of cardiogenic pulmonary edema with predilection for the right upper lobe and is strongly associated with severe mitral regurgitation 1, 2. It is hypothesized that the regurgitation jet is directed towards the right superior pulmonary vein thus prefe...