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
Hemophagocytic lymphohistiocytosis
Hemophagocytic lymphohistiocytosis (HLH) is a non-malignant but often fatal disorder of immune dysregulation affecting multiple organs. It is also known as macrophage activation syndrome when occurring in the setting of a rheumatologic disorder.
Epidemiology
It typically affects infants and yo...
Article
Mantle cell lymphoma
Mantle cell lymphoma (MCL) is a type of non-Hodgkin lymphoma (NHL) and accounts for ~5% of all NHL. It is a malignant neoplasm of virgin B cells that closely resemble normal mantle zone B cells surrounding germinal centers.
Epidemiology
They occur in older adults (mean age ~60 years), and ther...
Article
Pyrexia
Pyrexia (or fever) is a clinical sign, indicated by an abnormally elevated core body temperature, which is defined by several medical societies as ≥38.3°C (≥≈101°F). The temperature elevation may be persistent or episodic. If the body temperature is greater than 41.5°C - a rare phenomenon - it i...
Article
Primary mediastinal large B-cell lymphoma
Primary mediastinal large B-cell lymphoma is a distinct entity, recognized in the WHO classification of lymphoma.
Epidemiology
Primary mediastinal large B-cell lymphoma accounts approximately 5% of large B-cell lymphoma, which is usually disseminated or found in the abdomen. There appears to b...
Article
Technetium-99m agents
Technetium agents based on the technetium-99m (Tc-99m) radioisotope are frequently used agents in medical imaging. A radiopharmaceutical labeled with Tc-99m constitutes a co-ordination complex in which ligands bond to a central atom of Tc-99m by co-ordinate covalent bonds 4 .
The radioactive te...
Article
Erythrocytosis
Erythrocytosis (or polycythemia) is the presence of an excessive number of red blood cells in the circulation. It can be primary or arise secondarily to another pathology.
Terminology
Absolute erythrocytosis is defined as a red cell mass which is >125% predicted for sex and age 2.
Although th...
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...
Article
Polycythemia vera
Polycythemia vera (older term: polycythemia rubra vera) is a myeloproliferative neoplasm that results in an excess of red blood cells in the bloodstream.
Terminology
The standalone word polycythemia, a.k.a. erythrocytosis, is the medical term for the presence of an excessive number of red bloo...
Article
Primary cutaneous lymphoma
Primary cutaneous lymphomas represent a group of extranodal non-Hodgkin lymphomas (T- or B-cell) primarily confined to the skin with no evidence of extracutaneous disease at the time of diagnosis (cf. secondary involvement of the skin).
Mycosis fungoides is the most prevalent type of primary c...
Article
Apheresis
Apheresis is an extracorporeal procedure in which the main components of blood (red blood cells, plasma, and plasma proteins) are separated and removed from the body. It is used as therapeutic measure for certain conditions.
Radiological implications
It is one of the indications of placement o...
Article
Secondary pulmonary lymphoma
Secondary pulmonary lymphomas refer to pulmonary involvement with lymphoma when the condition is not limited to the lung and has mediastinal lymph node involvement or evidence of extrathoracic dissemination for at least three months after the initial diagnosis. This is a more common form of pulm...
Article
Leukostasis
Leukostasis, also known as symptomatic hyperleukocytosis, is a medical emergency in patients with leukemia, particularly acute myeloid leukemia (AML) and in the blast phase of chronic myeloid leukemia (CML), characterized by the over-accumulation of leukemic cells within the small vessels. Altho...
Article
Thymic rebound hyperplasia
Thymic rebound hyperplasia is considered a form of true thymic hyperplasia.
Pathology
In periods of bodily stress the thymus may acutely shrink to 40% of its original volume (depending on the severity and duration of the stress). During the recovery phase it can grow back to its original size ...
Article
Mediastinal lymph node enlargement
Mediastinal lymph node enlargement can occur from a wide range of pathologies and can be isolated or associated with lung pathology. Historically, a size cut-off of 10 mm short-axis diameter was used.
Terminology
The term mediastinal lymphadenopathy implies lymph node disease and is not synon...
Article
Yttrium-90 ibritumomab tiuxetan
Yttrium-90 ibritumomab tiuxetan, also known by the trade name Zevalin (Acrotech Biopharma LLC, USA), is a theranostic radiopharmaceutical approved for the treatment of patients with relapsed or refractory low grade or follicular non-Hodgkin lymphoma (NHL). More specifically, it is a radioimmunot...
Article
Concentric target sign (cerebral toxoplasmosis)
The concentric target sign is a typical sign of cerebral toxoplasmosis. It is seen on T2 weighted MR imaging as a deep parenchymal lesion showing a series of concentric rings with hyperintense and hypointense/isointense signals alternatingly. Strong perifocal edema is usually visible on T2/FLAIR...
Article
Nezelof syndrome
Nezelof syndrome is a hereditary primary immunodeficiency state caused by thymic dysplasia, lack of T cell function and normal levels of immunoglobulins.
Epidemiology
Nezelof syndrome is extremely rare.
Clinical presentation
Common clinical features include 4,5
failure to thrive
metaphysea...
Article
Non-Hodgkin lymphoma
Non-Hodgkin lymphoma (NHL) is a neoplasm of the lymphoid tissues originating from B cell precursors, mature B cells, T cell precursors, and mature T cells. It includes all types of lymphomas apart from Hodgkin lymphoma.
See the WHO classification of haematolymphoid tumors for further informatio...
Article
Autosplenectomy
Autosplenectomy denotes spontaneous infarction of the spleen with resulting hyposplenism.
Epidemiology
Autosplenectomy is most frequently encountered in patients with homozygous sickle cell disease, although it has also been reported in pneumococcal septicemia 1, and systemic lupus erythematos...
Article
Deauville five-point scale
The Deauville five-point scale (Deauville 5PS) is an internationally-recommended scale for routine clinical reporting and clinical trials using FDG PET-CT in the initial staging and assessment of treatment response in Hodgkin lymphoma (HL) and certain types of non-Hodgkin lymphomas (NHL).
Incl...
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