Articles
Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and continuously improved upon by countless contributing members. Our dedicated editors oversee each edit for accuracy and style. Find out more about articles.
16,834 results found
Article
Polycystic ovarian syndrome
Polycystic ovarian syndrome (PCOS), also known as hyperandrogenic anovulation, is a chronic anovulation syndrome associated with androgen excess.
The Rotterdam criteria is used to make the diagnosis of PCOS and require any two of the following three criteria for the diagnosis, as well as the e...
Article
Polycystic ovaries
Polycystic ovaries (PCO) or polycystic ovarian morphology (PCOM) is an imaging descriptor of a particular type of change in ovarian morphology. A proportion of women with polycystic ovaries will have the polycystic ovarian syndrome (PCOS), which in turn requires additional clinical, as well as b...
Article
Osteoporosis
Osteoporosis is a metabolic bone disease characterized by decreased bone mass and skeletal fragility.
The World Health Organization (WHO) operationally defines osteoporosis as a bone mineral density T-score less than -2.5 SD (more than 2.5 standard deviations under the young-adult mean), which ...
Article
Sonic hedgehog-activated hepatocellular adenoma
Sonic hedgehog-activated hepatocellular adenomas (sh-HCA) are a subtype of hepatocellular adenomas.
On imaging, it is still mostly diagnosed by exclusion of the other adenomas subtypes and other liver tumors.
Epidemiology
Most of sh-HCA were previously grouped under the unclassified adenomas,...
Article
Incidental thyroid nodule
Incidental thyroid nodules, sometimes called thyroid incidentalomas, are discrete lesions in the thyroid gland found on cross-sectional imaging performed for indications other than thyroid evaluation. They are common but occasionally represent thyroid cancer 1. This article discusses the epidemi...
Article
Brain metastases
Brain metastases are estimated to account for approximately 25-50% of intracranial tumors in hospitalized patients. Due to great variation in imaging appearances, these metastases present a common diagnostic challenge that can importantly affect the management approach for individual patients.
...
Article
CSF-venous fistula
CSF-venous fistulas are an underdiagnosed cause of spontaneous intracranial hypotension. They are direct communication between the spinal subarachnoid space and epidural veins allowing for the loss of CSF directly into the circulation and can be either iatrogenic or spontaneous in etiology.
Ep...
Article
Periprocedural anticoagulation
Periprocedural anticoagulation planning is essential when planning an interventional procedure so that the best balance between the risk of bleeding and thrombosis can be achieved.
The following must be considered in assessment of periprocedural anticoagulation:
bleeding risks associated with ...
Article
Pulmonary hypertension
Pulmonary hypertension is currently defined as a resting mean pulmonary arterial pressure of >20 mmHg at right heart catheterization, which is a hemodynamic feature that is shared by all types of pulmonary hypertension.
A resting mean pulmonary arterial pressure of ≤20 mmHg is considered normal...
Article
Lymphatic system
The lymphatic system (also known as the lymphoid system or systema lymphoideum in Terminologia Anatomica) is the collective term given to the lymphatic vessels and lymphoid tissues in the body 1,4.
Terminology
Occasionally the lymphatic system is considered with the reticuloendothelial system ...
Article
Nigrosomes
Nigrosomes are small clusters of dopaminergic cells within the substantia nigra that exhibit calbindin D28K negativity on immunohistochemistry. Five nigrosomes measuring up to a few millimeters in size have been described with the largest labeled as nigrosome-1 1.
Nigrosome-1
Nigrosome-1 withi...
Article
White coat hypertension
White coat hypertension (WCH or WCHT), and not to be confused with the white coat effect (WCE), is commonly defined as typical in-clinic blood pressure (BP) measurements of 140/90 mm Hg or more in the presence of multiple daytime out-of-clinic home or ambulatory BP readings averaging less than 1...
Article
Alzheimer disease
Alzheimer disease is a common neurodegenerative disease, responsible for 60-80% of all dementias, and imposing a significant burden on developed nations. It is associated with an accumulation and deposition of cerebral amyloid-β (Aβ) and is the most common cerebral amyloid deposition disease.
...
Article
Leber hereditary optic neuropathy
Leber hereditary optic neuropathy (LHON) is a mitochondrial genetic disorder characterized by bilateral, progressive, central vision loss secondary to loss of the retinal ganglionic cell layer 1,2.
Epidemiology
Leber hereditary optic neuropathy classically presents in young, Caucasian, adult m...
Article
Lobar intracerebral hemorrhage
Lobar intracerebral hemorrhage is a subtype of intracerebral hemorrhage defined by their location in the peripheral cerebral hemispheres. Compared to deep intracerebral hemorrhages (involving the deep grey nuclei or brainstem), lobar hemorrhages are less likely to be related to hypertension and ...
Article
Multinodular and vacuolating neuronal tumor
Multinodular and vacuolating neuronal tumors (MVNT) are lesions with distinct cytoarchitectural patterns. They are often considered part of the heterogeneous group of tumors known as long-term epilepsy-associated tumors (LEATs).
Radiologically, MVNTs appear as small "bubbly" indolent subcortica...
Article
Pool sign (intracranial; metastatic adenocarcinoma)
The pool sign describes the brain MRI appearance whereby an intracranial mass exhibits a T2 hyperintense rim adjacent to a solid mass surrounded by peritumoral edema. This appearance has suggested to be a feature characteristic of metastatic adenocarcinoma (with various primaries).
The "pool" p...
Article
Central vein sign
The central vein sign is a marker for multiple sclerosis (MS) and is the imaging manifestation of the perivenular nature of demyelinating plaques. It is not pathognomonic but can be useful in helping differentiate multiple sclerosis from mimics, such as cerebral small vessel disease, neuromyelit...
Article
Amyand hernia
Amyand hernias (alternative plural: herniae) are a rare form of inguinal hernia in which the vermiform appendix is located within the hernial sac. They are seen in less than 1% of inguinal hernias.
It should not be confused with an appendix-containing femoral hernia, known as a De Garengeot he...
Article
Esophageal web
Esophageal webs refer to an esophageal constriction caused by a thin mucosal membrane projecting into the lumen.
Epidemiology
Esophageal webs tend to affect middle-aged females.
Clinical presentation
Patients are usually asymptomatic and the finding may be incidental and unimportant. However...