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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 edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

13 results found

Diffuse T1 bone marrow signal loss

Diffuse T1 vertebral bone marrow signal loss is associated with replacement of fatty marrow by edema or cellular tissue. T1-weighted imaging without fat suppression is one of the most important sequences for distinguishing between normal and abnormal bone marrow. In the case of homogenous involv...


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. Definition Absolute erythrocytosis is defined as a red cell mass which is >125% predicted for sex and age 2. Although the...

Gallbladder cholesterol polyps

Gallbladder cholesterol polyps are the most common subtype of gallbladder polyps, representing more than 50% of all polyps. They are frequently seen in middle-aged women and are benign lesions, with no malignant potential.  For further details, please refer to the parental article on gallbladde...

Hemolytic anemia

Hemolytic anemia is a form of anemia where red blood cells (RBCs) are destroyed either intravascularly or extravascularly. Clinical presentation The patient presents with anemia and jaundice. Diagnosis is based on several laboratory parameters 1: reticulocytosis increased unconjugated biliru...


Hepatosplenomegaly is simply the simultaneous presence of a pathologically-enlarged liver (hepatomegaly) and spleen (splenomegaly). Pathology Etiology Infection Many, many infections can produce a mild concurrent enlargement of the liver and spleen. This list is by no means exhaustive! vira...

Lead poisoning

Lead poisoning or plumbism is a multisystem condition due to the way in which lead interferes with the function of virtually every organ system. Plumbism most severely manifests due to its devastating effects on the CNS, but it also has important deleterious consequences on the skeletal, renal, ...

Mediastinal lymph node enlargement

Mediastinal lymph node enlargement can occur from a wide range of pathologies, either by its own or in association with other lung pathology. Historically a size cut-off of 10 mm short-axis diameter was used.  Terminology Although mediastinal lymphadenopathy is used interchangeably - by some -...

PET-CT indications

PET-CT is a combination of cross-sectional anatomic information provided by CT and the metabolic information provided by positron emission tomography (PET). PET is most commonly performed with 2-[F-18]fluoro-2-deoxy-D-glucose (FDG). Fluorine-18 (F-18) is an unstable radioisotope and has a half-...

Pleural lymphoma

Pleural involvement with lymphoma can occur in two situations: primary pleural lymphoma primary effusion lymphoma secondary involvement of the pleura with lymphoma

Primary immunodeficiency states

The primary immunodeficiency states are a heterogenous group of disorders that occur when there is an impairment of humoral or cell-mediated immunity in the absence of any recognized precipitating cause such as drug therapy or infective agent such as human immunodeficiency virus (HIV). Epidemio...

Splenic cyst

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 pseudocyst

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:  splen...


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...

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