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.
746 results found
Article
Hemolytic anemia
Hemolytic anemia is a form of anemia where red blood cells are destroyed faster than they can be replaced. This may happen either intravascularly or extravascularly.
Clinical presentation
The patient presents with anemia and jaundice. Diagnosis is based on several laboratory parameters 1:
ret...
Article
Nerve root enhancement
Nerve root enhancement is a phenomenon described on post-contrast MRI scans that can be observed in a number of situations.
Common causes
post-operative nerve root enhancement 6
arachnoiditis
leptomeningeal metastases
disseminated spinal leptomeningeal metastases
neurolymphomatosis
HIV va...
Article
Dural ectasia
Dural ectasia refers to ballooning or widening of the dural sac which can result in posterior vertebral scalloping and is associated with herniation of nerve root sleeves.
Clinical presentation
Patients with dural ectasia may present with low back pain or radicular pain in the buttocks or legs...
Article
Spinal metastasis
Spinal metastasis is a vague term that can be variably taken to refer to metastatic disease to any of the following:
vertebral metastases (94%)
may have epidural extension
intradural extramedullary metastases (5%)
intramedullary metastases (1%)
Each of these are discussed separately. Below ...
Article
Perianal disease
Perianal disease, also known as anorectal disease, is the collective name given to a group of diseases that primarily affect the anal canal +/- rectum. The disease spectrum ranges from the typically benign, e.g. hemorrhoids, to the potentially more serious, e.g. perianal fistula 1-3.
hemorrhoid...
Article
Splenic lesions and anomalies
There are a number of splenic lesions and anomalies:
Gamuts
hypervascular splenic lesions
Congenital anomalies
accessory spleen
wandering spleen
asplenia
polysplenia
bipartite spleen
splenogonadal fusion
retrorenal spleen
Mass lesions
Benign mass lesions
splenic cyst
splenic pseudo...
Article
Pneumatocele
Pneumatoceles are intrapulmonary gas-filled cystic spaces that can have a variety of sizes and appearances. They usually occur as a result of a pneumonia or in neonates are the result of a ventilator-induced lung injury. They should not be mistaken for a cavitating lung mass.
Epidemiology
Alt...
Article
Pure ground glass nodules
Pure ground glass lung nodules (pGGN's) are a subtype of ground glass lung nodules where there is no associated solid component.
Pathology
Etiology
Apart from inflammatory foci they have been shown to represent various pathologies such as 1,3
adenocarcinoma in situ of lung
minimally-invasiv...
Article
Cardiac calcification
Cardiac calcification is a broad term for any calcification affecting the valves, coronary arteries, aortic root, endocardium, myocardium, and/or pericardium.
Pathology
Causes of cardiac calcification are:
coronary artery disease (most common)
coronary artery aneurysms, e.g. in Kawasaki dise...
Article
Terminal ileitis (differential)
The differential diagnosis for a terminal ileitis is quite extensive, and includes:
inflammatory bowel disease
Crohn disease (most common)
backwash ileitis due to ulcerative colitis
infectious colitis
Yersinia spp.
Yersinia enterocolitica
Yersinia pseudotuberculosis
Salmonella spp.
Sa...
Article
Reverse bat wing pulmonary opacities
Reverse bat wing pulmonary opacities refer to peripheral opacities of the lungs, sparing the perihilar region. It is a relatively unusual appearance with a fairly narrow differential 1:
common
chronic eosinophilic pneumonia 2,3
organizing pneumonia 3,5
rare
pulmonary contusion: in the setti...
Article
Surgical sieve (mnemonic)
A surgical sieve is an approach to differential diagnosis that prompts the user to consider various types of pathologies systematically. A surgical sieve does not need to be a mnemonic 2, although many find it easier to remember it when a mnemonic is used. Various versions of this mnemonic exist...
Article
Pituitary region mass with intrinsic high T1 signal
Pituitary region masses with intrinsic high T1 signal, also referred to as suprasellar hotspots, are relatively frequently encountered, and the presence of high T1 signal narrows the differential somewhat.
Differential diagnosis
The differential can be divided by the substance causing the T1 ...
Article
Shortening of the fourth/fifth metacarpals
Shortening of the fourth/fifth metacarpals (brachymetacarpia) and less commonly metatarsals (brachymetatarsia) is seen in a variety of apparently disparate conditions.
Pathology
Etiology
Common causes 2:
idiopathic
post-infective (e.g. osteomyelitis, yaws, tuberculosis dactylitis)
pseudoh...
Article
Nontoxic megacolon
Nontoxic megacolon refers to colonic dilatation without mural abnormality and signs of colon toxicity. Although the definition of a megacolon has varied in the literature, most use the measurement of greater than 12 cm for the cecum, 8 cm for the ascending and transverse colon, and 6.5 cm for th...
Article
Cerebral cortical calcification
Cerebral cortical calcification or gyral calcification refers to curvilinear calcifications involving the cerebral cortex.
Differential diagnosis
vascular
ischemic stroke sequelae
arteriovenous malformation
TORCH infection
congenital cerebral toxoplasmosis
congenital cytomegalovirus infec...
Article
Optic canal enlargement
Optic canal enlargement can be caused by numerous etiologies.
Pathology
The optic canal has an average transverse diameter of 3.6 ± 0.6 mm 1. The optic canal can be considered enlarged when it is >6.5 mm in transverse diameter 4.
Etiology
glioma of optic nerve
meningioma of optic nerve shea...
Article
Lumbar epidural gas
Lumbar epidural gas is a rare phenomenon where gas locules are observed within the central canal of the lumbar spine. It can arise from a number of factors:
due to regional degenerative disc disease with or without dorsal epidural disc migration: thought to be from gas leaking from the disc spa...
Article
Communicating hydrocephalus
Communicating hydrocephalus is a type of hydrocephalus where CSF is able to leave the ventricular system.
Terminology
Communicating hydrocephalus is commonly used as the opposite of obstructive hydrocephalus, which leads to much unnecessary confusion, as most causes of communicating hydroceph...
Article
Urinary bladder wall thickening
Urinary bladder wall thickening is a common finding and its significance depends on whether the bladder is adequately distended.
Radiographic features
Ultrasound
In both adults and children, the wall may be considered thickened on ultrasound if it measures 6:
>3 mm when distended (>25% expec...
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