Adhesive capsulitis of the shoulder, also known as frozen shoulder, is a condition characterised by thickening and contraction of the shoulder joint capsule and surrounding synovium. Adhesive capsulitis can rarely affect other sites such as the ankle 8.
The incidence in the genera...
Adhesive otitis media is a form of chronic otitis media where there is a adhesion of medial ear structures as a result of chronic inflammation. There are often complete or partial adhesions between the thin retracted and atrophic pars tensa and the medial wall of the middle ear.
Adie pupil (also known as tonic pupil) is caused by idiopathic degeneration of the ciliary ganglion, which sometimes occurs following a viral or bacterial illness. It is usually unilateral and typically affects young females 1.
Adie pupil represents a large dilated "tonic pupil", which does not...
Adie syndrome consists of a classic triad of:
absent deep tendon reflexes, e.g. ankle jerk
an Adie pupil: tonically dilated and responds poorly or not at all to light
It is thought to result from damage to the ciliary ganglion and the dorsal root ganglion by viral or bacterial in...
The ADIR (ADduction and Internal Rotation) position relates to MR arthrography of the shoulder joint.
When added to a neutral-position shoulder protocol, MR arthrography in the ADIR position facilitates the diagnosis of labroligamentous lesions in patients with recurrent shoulder dislocations, ...
Adjacent level ossification is a complication of anterior cervical discectomy and fusion (ACDF) with anterior plate stabilisation. It represents pathological heterotopic ossification of the soft tissues above or below the ends of the plate, contiguous with the adjacent vertebral body. It occurs ...
Adjacent segment degeneration is a common complication of spinal fusion occurring at the adjacent unfused level above or below the fused segment. It is usually encountered in the cervical spine or lumbar spine and occurs with an incidence of roughly between 2% and 4% per year 4.
Adnexa is a general term that refers to the accessory structures of an organ.
Adnexa have been described with:
hair follicles, sweat glands, nails
structures in the mastoid (posterior) wall of the middle ear, e.g. mastoid antrum, aditus ad antrum, mast...
The term adnexal torsion refers to torsion of the pelvic adnexal structures. This can encompass ovarian torsion + / - tubal torsion.
Adrenal abscesses are rare lesions affecting the adrenal glands and are usually encountered in the setting of disseminated infection.
Although cases have been described in both neonates and adults, no systematic literature is available on the epidemiology of adrenal abscesses.
Adrenal adenomas are the most common adrenal mass lesion and are often found incidentally during abdominal imaging for other reasons. In all cases, but especially in the setting of known current or previous malignancy, adrenal adenomas need to be distinguished from adrenal metastases or other ad...
The adrenal glands are supplied by three adrenal (suprarenal) arteries:
superior adrenal artery: arises from ipsilateral inferior phrenic artery
middle adrenal artery: arises from lateral side of abdominal aorta
inferior adrenal artery: arises from the ipsilateral renal artery
Adrenal calcification is not a rare finding in healthy asymptomatic people and is usually the result of previous haemorrhage or tuberculosis. Addison disease patients only occasionally develop calcification.
sepsis: Waterhouse-Friderichsen syndrome
An adrenal collision tumour or collision tumour of the adrenal gland is an uncommon condition where two histologically distinct tumours abut each other or are in close proximity in the same adrenal gland.
Collision tumours have been reported in nearly every organ, for example, collis...
Primary adrenal cortical carcinoma is a highly malignant but rare neoplasm. It may present as a hormonally active or inactive tumour.
Although men and women are affected equally, functioning tumours are more common in females, who are also more likely to have an associated endocr...
Adrenal cysts are rare lesions and are commonly incidental findings.
Adrenal cysts are reported to be rare with an incidence of <1% 1.
Patients can present with pain or swelling, although a significant portion (~40%) are incidental findings 1,3.
The adrenal (suprarenal) glands are paired organs of the endocrine system, often asymmetric in shape.
Each gland is enclosed in the perirenal fascia and each has a body and two limbs: a medial limb and a lateral limb. However, the right adrenal gland is usually more pyramidal in...
Adrenal gland trauma most commonly results from blunt force trauma.
Adrenal gland trauma is present on 1-2% of CT imaging in blunt trauma although the occurrence is thought to be much higher as injury has been demonstrated at 28% in one autopsy series 1-4.
The right adrenal glan...
Despite its small size, the adrenal gland is affected by a relatively large number of neoplastic entities:
adrenal cortical carcinoma
adrenal lesions: for a more general list of...
Adrenal haemangiomas are rare benign tumours that are usually incidentally identified (one example of an adrenal incidentaloma). Its significance mainly relates to the difficulty in differentiation from other malignant lesions.
Although these can be found at any age, they are mos...
Adrenal haemorrhage can result from a variety of traumatic and non-traumatic causes. When unilateral, it is often clinically silent. In contrast, bilateral adrenal haemorrhage can lead to catastrophic adrenal insufficiency.
The large majority of patients with unilateral a...
Adrenal hyperplasia refers to nonmalignant growth (enlargement) of the adrenal glands and is a rare cause of ACTH-independent Cushing syndrome, with unilateral adrenal cortical adenomas being the commonest. 20% of Conn syndrome cases are secondary to adrenal hyperplasia. In diffuse hyperplasia, ...
Adrenal insufficiency refers to inadequate secretion of corticosteroids (glucocorticoids and mineralocorticoids).
It may occur from partial or complete destruction of the adrenal cortex, in which case it is termed primary adrenal insufficiency (also known as Addison disease). Secon...
Adrenal lesions cover a broad spectrum from benign to neoplastic entities. Due to increased use of cross-sectional imaging they are frequently detected as incidental lesions ("incidentalomas"). If found incidentally, please refer to the Management of incidental adrenal masses: American College o...
Adrenal lymphangiomas, also known as cystic adrenal lymphangiomas, are rare, benign cystic adrenal lesions.
Adrenal lymphangiomas are extremely rare; prevalence is estimated at 0.06% 8. They can occur at any age, with a peak incidence between the 3rd and 6th decades of life. Accor...
Adrenal metastases are the most common malignant lesions involving the adrenal gland. Metastases are usually bilateral but may also be unilateral. Unilateral involvement is more prevalent on the left side (ratio of 1.5:1).
They are present at autopsy in up to 27% of patients with ...
Adrenal myelolipomas are rare benign, and usually asymptomatic, tumours of the adrenal gland characterised by the predominance of mature adipocytes.
On imaging, they usually present as large masses with a variable amount of fat-containing components.
Rare tumours with estimated ...
Adrenal pseudocysts account for ~40% of adrenal cysts and are more likely than simple adrenal cysts to be symptomatic.
Pseudocysts do not have an epithelial lining and typically arise after an episode of adrenal haemorrhage. There is an ~7% association with malignancy (e.g. from haem...
The venous drainage of the adrenal (suprarenal) glands is typically comprised of a single vein draining each adrenal gland. Like the gonadal veins each side drains differently:
left suprarenal vein drains into the left renal vein 1.
right suprarenal vein drains directly into the inferior vena ...
Adrenal vein sampling (AVS) is a procedure where blood is collected from the adrenal veins via catheter to confirm autonomous hormone production, if it is unilateral or bilateral, and to guide further treatment.
AVS is commonly performed in primary aldosteronism, being indicated to ...
Adrenal washout can be calculated using the density value of an adrenal mass on non-enhanced, portal venous phase and 15 minutes delayed CT-scans (density measured in Hounsfield units (HU)). It is primarily used to diagnose adrenal adenoma.
[(HUportal venous phase) - (HUdelaye...
Adrenocorticotropin independent macronodular adrenocortical hyperplasia (AIMAH) is considered a rare form of macronodular adrenal hyperplasia. It is an uncommon cause of primary adrenal hypercortisolism.
Patients with AIMAH tend to present 10 years earlier on average than...
Adrenoleukodystrophy (ALD) is an X-linked inherited metabolic peroxisomal disorder characterised by a lack of oxidation of very long chain fatty acids (VLCFAs) that results in severe inflammatory demyelination of the periventricular deep white matter with posterior-predominant pattern and early ...
Cervical lymphadenopathy in an adult can result from a vast number of conditions. They include:
from head and neck tumours
other neoplastic lesions
Adult chest radiograph common exam pathology is essential to consider in the build up to radiology exams. The list of potential diagnoses is apparently endless, but there are some favourites that seem to appear with more frequency.
When dealing with the adult chest radiograph in the exam settin...
A chest radiograph in the exam setting may contain a vast variety of pathology. However, consider the history and correlate the likely diagnoses that may be demonstrated on film. Furthermore, check your review areas to ensure that the abnormality isn't at the corner of the film.
The adult chest radiograph pathology checklist is just a pathology checklist of things not to miss when reviewing a chest radiograph, especially in the exam setting.
standard review areas
below the diaphragm
right descending pulmonary artery (like a l...
There are a number of adult chest radiograph set-pieces. These are based on common patterns of disease that are seen on chest radiographs. Make sure that you have relevant differentials for these appearances and a quick aural set-piece for them when they come up.
Adult cystic renal disease comprises multiple distinct hereditary and non-hereditary disease processes.
adult polycystic kidney disease (APCKD), a.k.a. autosomal dominant polycystic kidney disease (ADPCKD)
medullary cystic kidney disease
von Hippel-Lindau di...
Whenever you look at an adult elbow x-ray, review:
Check the anterior humeral line:
drawn down the anterior surface of the humerus
should intersect the middle 1/3 of the capitellum
if it doesn't, think distal humeral fracture
Adult granulosa cell tumour of the ovary is a type of ovarian sex cord / stromal tumour. They are by far the most frequent subtype of granulosa cell tumours of the ovary (95%) and are commoner than the juvenile granulosa tumour of the ovary.
Approximately two-thirds of this subtyp...
Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP), also known as hereditary diffuse leukoencephalopathy with spheroids (HDLS) and pigmentary orthochromatic leukodystrophy (POLD), refers to a rare inherited autosomal dominant disease characterised by an adult-onset l...
Adult-onset Still disease is a rare multisystem inflammatory disorder.
Still disease in adults is rare affecting around 1.5 per 100,000 people, it occurs in a bimodal distribution with one peak around the age of 15-25 years old and another around the age of 35-45 years old 1. It a...
Adventitial bursae are those bursae that develop later in life in response to pressures developed as a result of acquired bony prominences or deformities 1. These bursa can become inflamed resulting in adventitious bursitis.
Adventitious or adventitial bursitis refers to inflammation associated with adventitious bursae.
Adventitious bursae are not permanent native bursae. They can develop in adulthood at sites where subcutaneous tissue becomes exposed to high pressure and friction.
Adynamic ileus is the failure of passage of enteric contents through the small bowel and colon that are not mechanically obstructed. Essentially it represents the paralysis of intestinal motility.
Patients may be asymptomatic or present with symptoms similar to a mechanic...
Afferent loop syndrome is an intermittent partial or complete mechanical obstruction of the afferent limb of a gastrojejunostomy.
The syndrome classically refers to obstruction of the upstream limb of a side-to-side gastrojejunostomy, but has also been used to refer to the biliopancreatic limb ...
Aflatoxins are naturally occuring mycotoxins that are produced by Aspergillus species, especially Aspergillus flavus. They are acutely toxic and carcinogenic.
High-level aflatoxin exposure can result in acute aflatoxicosis with acute hepatic necrosis, leading to cirrhosis, and p...
Human alpha fetoprotein (AFP) elevation may occur in a vast number of conditions:
liver tumours (hepatocellular carcinoma, hepatoblastoma)
<10 ng/ml is within normal limits
>20 ng/ml is above normal limits but has low specificity for tumour since it may occur in a setting of diffuse liver inj...
Human AFP (alpha-fetoprotein) reduction is seen in pregnancy where it can be associated with:
certain chromosomal anomalies
Cornelia de-Lange syndrome 2
Agatston score is a semi-automated tool to calculate a score based on the extent of coronary artery calcification detected by an unenhanced low-dose CT scan, which is routinely performed in patients undergoing cardiac CT. Due to an extensive body of research, it allows for an early risk stratifi...
The imaging characteristics of blood on MRI can be variable and change with the age of the blood.
In general, five stages of haematoma evolution are recognised:
isointense on T1
isointense to hyperintense on T2
acute (1 to 2 days)
Ageing blood on MRI is dependent on the varying MRI signal characteristics of haemorrhagic collections with time and can be very useful in correlating the imaging findings with the clinical picture. However, as it can be complicated to recall the MRI features of ageing blood through the five sta...
Agenesis of the diaphragm is a congenital diaphragmatic developmental anomaly where all or part of diaphragm fails to form. It can sometimes be thought of as an extreme form congenital diaphragmatic herniation 1.
The agenesis can either be unilateral or bilateral. Herniation of abdom...
Agenesis of the left hepatic lobe is a rare variation in liver anatomy. It is clinically asymptomatic and discovered during imaging or surgery.
absence of the left hepatic lobe (left of the falciform ligament, Couinaud segments II and III)
absence of left hepatic artery,...
Agenesis of the right hepatic lobe is a rare variation in liver anatomy.
absence of the right hepatic lobe
absence of right hepatic artery, right portal vein, and right hepatic biliary system
compensatory hypertrophy of the left hepatic lobe and caudate lobe
Agger nasi air cells are the most anterior ethmoidal air cells lying anterolateral and inferior to the frontal recess and anterior and above the attachment of the middle turbinate. They are located within the lacrimal bone and therefore have as lateral relations the orbit, the lacrimal sac and t...
Aggressive angiomyxomas are rare tumours that arise in the pelvis and typically cross the levator ani muscles. Despite its name, it is essentially a benign tumour and the term "aggressive" is given due to a predilection for local recurrence. Only rarely does it metastasise.
It is ...
Aggressive fibromatosis is a type of musculoskeletal fibromatosis. While it is a non-metastasising fibrous lesion, it is thought to be a true neoplasm that arises from the fascial and musculoaponeurotic coverings, sometimes at the site of a traumatic or post-surgical scar.
Aggressive granulomatosis post hip replacement is a potential complication of a hip joint replacement. Some authors use the same term for particle disease - if you are an expert on this we would love your help.
Aggressive granulomas consist of well organised connective tissue contain...
Agnosia is a neurological disorder characterised by an inability to identify an object despite both having knowledge of that object and functional sensory input. For example, a patient with posterior cortical atrophy who characteristically have visual agnosia, will be unable to identify a hammer...
This classification was proposed by Ahlback et al. in 1968.
According to Ahlbäck system, knee joint osteoarthritis is classified as:
grade 1: joint space narrowing (less than 3 mm)
grade 2: joint space obliteration
grade 3: minor bone attrition (0-5 mm)
grade 4: moderate bone attrition (5-1...
AICA-PICA dominance refers to the principle that the cerebellar vascular territory supplied by the anterior inferior cerebellar artery and posterior inferior cerebellar artery have a reciprocal arrangement. That is the size of the AICA and the subsequent territory it supplies is inversely propor...
Aicardi syndrome is a rare severe developmental disorder. It results from an X-linked genetic defect that is fatal in males and therefore only manifests in females (except for rare 47-XXY cases).
The typical presentation in infancy is with a triad of:
infantile spasms: salaa...
AIDS cholangiopathy refers to an acalculous, secondary opportunistic cholangitis that occurs in AIDS patients as a result of immunosuppression.
Characterised by multiple irregular strictures essentially indistinguishable from primary sclerosing cholangitis (PSC). There are four path...
AIDS-defining illnesses are conditions that in the setting of a HIV infection confirm the diagnosis of AIDS, and do not commonly occur in immunocompetent individuals 2. According to the CDC surveillance case definition 1, they are:
bacterial infections: multiple or recurrent
Acquired immuno deficiency syndrome (AIDS) embryopathy is characterised by a group of dysmorphic features, which manifests either before or after birth in offsprings of women who are infected by HIV virus. The diagnosis however is in disfavour according to some authors 2.
AIDS-related diffuse large B-cell lymphomas are one of the immunodeficiency-associated CNS lymphomas, and in western countries represented a dramatic increase in primary CNS lymphoma during the HIV/AIDS epidemic of the 1980s, although the incidence is likely lower in patients treated with HAART ...
AIDS-related pulmonary lymphoma (ARPL) is classified as a distinct form of pulmonary lymphoma. Pulmonary involvement is a common extranodal site in AIDS-related NHL.
ARPL is typically a high-grade B-cell non-Hodgkin's lymphoma and the majority of patients have advanced HIV infection,...
Ainhum ("dactylolysis spontanea") is a rare cutaneous condition in which a hyperkeratotic band partially or totally encircles a digit. The constriction thins the underlying bone, which is then prone to fracture. Some cases result in autoamputation.
Some have suggested that the dis...
Air bronchogram refers to the phenomenon of air-filled bronchi (dark) being made visible by the opacification of surrounding alveoli (grey/white). It is almost always caused by a pathologic airspace/alveolar process, in which something other than air fills the alveoli. Air bronchograms will not ...
This is a basic article for medical students and other non-radiologists
Air-bronchograms are gas-filled bronchi surrounded by alveoli filled with fluid, pus or other material. It is a very useful sign because it is highly sensitive and specific for the presence of lung consolidation rather than...
The air bubble sign is seen in CT of complicated (ruptured or infected) pulmonary hydatid cyst and refers to small bubbles of gas within the periphery of pulmonary mass and is helpful, particularly in endemic areas, in suggesting the diagnosis over other masses (e.g. metastases or primary lung t...
The air bubble sign is seen on CT of the brain and represents multiple small foci of air within the subarachnoid space, especially the Sylvian fissure.1
Although described as a sign of tension pneumocephalus it is also seen in pneumocephalus without elevated pressures.2
It should not be con...
An air crescent sign describes the crescent of air that can be seen in invasive aspergillosis, semi-invasive aspergillosis or other processes that cause pulmonary necrosis. It usually heralds recovery and is the result of increased granulocyte activity.
In angioinvasive fungal infection, the no...
The air gap technique is utilised for the magnification mammography view.
Magnification mammography is a high dose imaging technique which is generally utilised as a follow-up to a standard mammogram image series when a focal area needs to be more clearly examined 1. The air gap technique is ut...
The utilisation of the air gap technique in general radiography is limited due to the need for equipment facilitation to create the air gap when it is not inherent in the standard technique.
Horizontal-beam lateral hip
There are many different methods of performing the horizontal beam lateral ...
Air space disease, or alveolar lung disease, is a process in which there is a filling of the lung's alveoli / acini.
lobar or segmental distribution
tendency to coalesce
bat's wing (butterfly) distribution...
An air space nodule is a small (few millimeters to 1 cm), ill-defined, nodular opacity that is often centrilobular in location and is non-specific, seen in many conditions. Commonly it represents a focal area of consolidation or peribronchiolar inflammation, and can indicate endobronchial spread...
Airspace nodules are irregularly marginated nodular opacities with air bronchograms that tend to measure 8 mm in diameter. They are quite separate from pulmonary nodules that range in size, are homogeneous and well-defined (being surrounded by normal lung).
Air space opacification is a descriptive term that refers to filling of the pulmonary tree with material that attenuates x-rays more than the surrounding lung parenchyma. It is one of the many patterns of lung opacification and is equivalent to the pathological diagnosis of pulmonary consolidati...
This is a basic article for medical students and other non-radiologists
Air-space opacification is a descriptive term that refers to filling of the lung parenchyma with material that attenuates x-rays more than the unaffected surrounding lung tissue. It is the radiological correlate of the path...
The differential for air space opacities is extensive, and needs to be interpreted in context of chronicity (previous imaging) and clinical context. It is therefore useful to divide airspace opacities as follows:
acute airspace opacities with lymph node enlargement
acute airspace opacities: un...
Air trapping in chest imaging refers to retention of excess gas (“air”) in all or part of the lung, especially during expiration, either as a result of complete or partial airway obstruction or as a result of local abnormalities in pulmonary compliance. It may also sometimes be observed in norma...
Airway foreign bodies in children are potentially fatal, which is why immediate recognition is important. Unfortunately, delayed diagnosis is common.
Children under the age of four years are at increased risk of foreign body (FB) aspiration, with a slight male predominance 1.
Airway invasive aspergillosis refers to a form of invasive aspergillosis that affects the airways as the major or only feature.
It usually occurs in immunocompromised neutropenic patients, particularly AIDS patients. Aspergillosis affecting the airways as the major or only feature...
Airway pressure release ventilation (APRV) is an alternative mode for mechanical ventilation. It can be adopted as a method of alternative method for difficult-to-oxygenate patients with acute lung injury / acute respiratory distress syndrome (ALI/ARDS).
Its is usually not recommended in patien...
Alagille syndrome (AGS) is a congenital genetic multi-system disorder.
Infants typically present with symptoms relating to the liver where it is one of the most common causes of hereditary cholestasis.
AGS is inherited in an autosomal fashion with a mutation of...
Alanine is one of the compounds examined in MR spectroscopy. It resonates at 1.48 ppm chemical shift. It is elevated in meningiomas.
The alar ligaments join the lateral margins of the sloping upper posterior margin of the dens of C2 to the lateral margins of the foramen magnum (adjacent to the occipital condyles) and lie on either side of the apical ligament. They may be oblique or vertical and are thickest at the occipital a...
The Alberta stroke programme early CT score (ASPECTS) 1 is a 10-point quantitative topographic CT scan score used in patients with middle cerebral artery stroke. It has also been adapted for the posterior circulation (see below).
Segmental assessment of the MCA vascular territo...
Albert Salomon (1883-1976), a German surgeon, was the first physician to study x-rays of breast tissue.
to be completed
Development of mammography
Salomon worked at the Royal Surgical University Clinic in Berlin and from about 1913 x-rayed 3000 breast specimens obtained from the ...
Albert Soiland (1873-1946), was a key figure in the establishment of radiology as an independent medical specialty in the United States. He is most famously remembered for his crucial role in the founding of the American College of Radiology. He was also a pioneering radiotherapist.