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.
336 results found
Article
Acute lymphoblastic leukemia
Acute lymphoblastic leukemia (ALL) is a malignant disorder of the bone marrow characterized by the proliferation of the lymphoid progenitor cells, typically of the B cell lineage.
Epidemiology
Acute lymphoblastic leukemia is the commonest form of childhood leukemia, accounting for ~80% of pedi...
Article
Acute myeloid leukemia
Acute myeloid leukemia (AML), also referred to as acute myelogenous leukemia, is a hematological malignancy characterized by the abnormal clonal proliferation of immature myeloid precursors (myeloblasts) or poorly differentiated cells of the hematopoietic system. It primary infiltrates the bone ...
Article
Acute promyelocytic leukemia
Acute promyelocytic leukemia (APML) is a distinct subtype of acute myeloid leukemia.
Pathology
Genetics
It is defined by a balanced translocation between chromosomes 15 and 17 resulting in fusion of the promyelocytic leukemia gene (PML) on chromosome 15 with the retinoic acid receptor alpha g...
Article
Adenoid tonsil
The adenoid tonsils, or often just simply the adenoids (also known as the nasopharyngeal or pharyngeal tonsils), are paired foci of lymphatic tissue located on the superoposterior wall of the nasopharynx and form part of Waldeyer's ring.
Article
Afibrinogenemia
Afibrinogenemia, also called congenital afibrinogenemia, is a rare autosomal recessive inherited blood disorder due to deficiency of the clotting protein fibrinogen. The disorder is associated with increased risk of spontaneous hemorrhage1.
Epidemiology
Afibrinogenemia has an estimated prevale...
Article
Agammaglobulinemia
Agammaglobulinemia is a rare inherited immunodeficiency disorder, characterized by a complete absence of mature B cells, which can result in severe antibody deficiency and recurrent infections 1. This is in contrast to hypogammaglobulinaemia where there is a reduction in all types of gammaglobul...
Article
Agranulocytosis
Agranulocytosis refers to a situation where the absolute neutrophil count (ANC) falls to less than 100 neutrophils per microliter of blood. It predisposes to a very high risk of severe infection.
Pathology
It can be hereditary or acquired.
hereditary: usually due to genetic mutations in the ...
Article
AIDS-defining illness
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:
Infectious
bacterial infections: multiple or recurrent
ca...
Article
AIDS-related diffuse large B-cell lymphoma
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 antire...
Article
AIDS-related pulmonary lymphoma
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.
Pathology
ARPL is typically a high-grade B-cell non-Hodgkin's lymphoma and the majority of patients have advanced HIV infection,...
Article
All-trans-retinoic acid syndrome
All-trans-retinoic acid (ATRA) syndrome, is the more common cause of differentiation syndrome 8. Acute promyelocytic leukemia (APL) cells respond to therapeutic levels of this normal plasma derivative of vitamin A by maturating into normal granulocytes which can cause capillary leakage and organ...
Article
Anemia
Anemia is the presence of reduced hemoglobin in the blood. Formally, the World Health Organizatiοn (WHO) defines anemia by the hemoglobin concentration in the blood according to age and sex 1:
adult men: <130 g/L
adult women: <120 g/L
Values for pregnant women and children are different.
Cli...
Article
Anaplastic large cell lymphoma (ALK+/ALK-)
Anaplastic large cell lymphomas (ALCL) are group of mature T-cell lymphoma first described in 1985 as a large-cell neoplasm with anaplastic morphology immunostained by the Ki-1 antibody, which recognizes CD30.
The WHO classification of haematolymphoid tumors recognizes three distinct entities:
...
Article
Anaplastic lymphoma kinase (ALK) gene rearrangements
Anaplastic lymphoma kinase (ALK) gene rearrangements are known to occur in association with several tumors. The genes code for an enzyme called anaplastic lymphoma kinase (ALK) or ALK tyrosine kinase receptor (also known as CD246) which is thought to play a role in brain development and exerts i...
Article
Anatomy curriculum
The anatomy curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core anatomy knowledge for radiologists and imaging specialists.
General anatomy
Neuroanatomy
Head and neck anatomy
Thoracic anatomy
Abdominal and pelvic anatomy
Spinal anat...
Article
Anemia of chronic disease
Anemia of chronic disease, also known as anemia of inflammation, is a type of anemia caused by chronic inflammation.
Terminology
According to some sources, the term 'anemia of inflammation' should replace, or has already replaced, the terms 'anemia of chronic disease' and 'anemia of chronic d...
Article
Angioimmunoblastic T cell lymphoma
Angioimmunoblastic T-cell lymphoma (AITL) (previously known as angioimmunoblastic lymphadenopathy with dysproteinemia (AILD)) is a rare, aggressive (fast-growing) form of peripheral T-cell lymphoma. It only accounts for around 1-2% of all non-Hodgkin lymphoma. It is one of the more common subtyp...
Article
Anion gap metabolic acidosis causes (mnemonic)
A mnemonic to remember the commonest causes of anion gap metabolic acidosis is:
GOLDMARK
Mnemonic
G: glycols (ethylene glycol and propylene glycol)
O: oxoproline
L: L-lactate
D: D-lactate
M: methanol
A: aspirin
R: renal failure
K: ketoacidosis
Article
Ann Arbor staging system (historical)
The Ann Arbor staging system was the landmark lymphoma staging classification system for both Hodgkin lymphoma and non-Hodgkin lymphoma. It is named after the town of Ann Arbor in the US state of Michigan where the Committee on Hodgkin's Disease Staging Classification met in 1971 to agree on it....
Article
Antiphospholipid syndrome
Antiphospholipid syndrome (APLS) is a systemic autoimmune disorder. It is usually defined as the clinical complex of vascular occlusion and ischemic events occurring in patients with circulating antiphospholipid antibodies.
Clinical presentation
Antiphospholipid syndrome is characterized by ve...
Unable to process the form. Check for errors and try again.