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16,880 results found

Intrahepatic arterioportal shunt

Intrahepatic arterioportal shunts, also known as arterioportal fistulas, represent abnormal flow between the portal venous system and a hepatic arterial system within the liver. They can be a reversible cause of portal hypertension. Clinical presentation Clinical features will depend on the si...

Trichilemmal cyst

Trichilemmal cysts, also known as pilar cysts, are benign accumulations of keratin along the outer hair root sheath, most commonly on the scalp. They are the most common subcutaneous nodule incidentally found on head imaging and are of no clinical relevance when asymptomatic 1. Uncommonly, they ...

Schistosomiasis (urinary tract manifestations)

Bladder schistosomiasis, also known as bilharzia of the bladder, is an infection by the Schistosoma flukeworm and is a major health problem in developing parts of the world predisposing individuals to bladder squamous cell carcinoma. Epidemiology Schistosomiasis is very common, affecting over ...

Arachnoid cyst

Arachnoid cysts are relatively common benign and asymptomatic lesions occurring in association with the central nervous system, both within the intracranial compartment (most common) as well as within the spinal canal. They are usually located within the subarachnoid space and contain CSF.  On ...

Superior mesenteric artery syndrome

Superior mesenteric artery (SMA) syndrome, also known as Wilkie syndrome, cast syndrome or aortomesenteric duodenal compression syndrome, is a rare acquired vascular compression disorder in which acute angulation of the superior mesenteric artery (SMA) results in compression of the third part of...

Mucinous adenocarcinoma of the prostate

Mucinous adenocarcinomas of the prostate or colloid adenocarcinomas of the prostate are a variant of acinar adenocarcinoma and characterized by mucinous features. Epidemiology Mucinous adenocarcinomas of the prostate are rare and account for less than 0.5% of prostate cancers 1-4. Diagnosis ...

Neurofibromatosis type 1

Neurofibromatosis type 1 (NF1), also known as von Recklinghausen disease, is a multisystem neurocutaneous disorder, the most common phakomatosis, and a RASopathy. Additionally, it is also one of the most common inherited CNS disorders, autosomal dominant disorders, and inherited tumor syndromes....


Grids are placed between the patient and the x-ray film to reduce the scattered radiation reaching the detector (produced mainly by the Compton effect) and thus improve image contrast. They are made of parallel strips of high attenuating material such as lead with an interspace filled with low ...

Choroid plexus papilloma

Choroid plexus papillomas are an uncommon, benign (WHO grade 1) neuroepithelial intraventricular tumor, which can occur in both the pediatric (more common) and adult population.  On imaging, these tumors are usually identified in the fourth ventricle in adults and in the lateral ventricles in t...

Tuberous sclerosis (mnemonic)

The findings of tuberous sclerosis can be remembered with the help of the following mnemonic: HAMARTOMAS Mnemonic H: hamartomas (CNS, retinal and skin) A: angiofibroma (facial) or adenoma sebaceum M: mitral regurgitation A: ash-leaf spots R: rhabdomyoma (cardiac) T: tubers (cortical, sub...

Sturge-Weber syndrome (mnemonic)

Some key findings pertaining to Sturge-Weber syndrome may be recalled using the following mnemonics: STURGE CAPS 8 Cs Mnemonics STURGE CAPS S: seizures, sporadic T: tram-track gyriform calcification; trigeminal territory port-wine stain U: unilateral weakness (hemiparesis contralateral to...

Superior medullary velum

The superior (or anterior) medullary velum is a thin layer of tissue that is suspended between the superior cerebellar peduncles forming the roof of the fourth ventricle along with the inferior medullary velum. It is enclosed by pia mater dorsally and ependyma ventrally. The lingula of the vermi...

Ischemic stroke

Ischemic stroke is an episode of neurological dysfunction due to focal infarction in the central nervous system attributed to arterial thrombosis, embolization, or critical hypoperfusion. While ischemic stroke is formally defined to include brain, spinal cord, and retinal infarcts 1, in common u...

Hemorrhagic transformation of ischemic stroke

Hemorrhagic transformation is a complication of cerebral ischemic stroke and can significantly worsen prognosis. Terminology The term hemorrhagic transformation is somewhat variably used and collectively refers to two different processes, which have different incidence, appearance and prognost...

CT angiographic spot sign (intracerebral hemorrhage)

The spot sign is a CTA sign in acute intracerebral hemorrhage representing the focal accumulation/pooling/extravasation of contrast containing blood within the hematoma. It is an important feature to identify during the evaluation of acute intracerebral hemorrhage as it significantly increases t...

Blumcke classification of focal cortical dysplasia

Blumcke et al. proposed the widely adopted International League Against Epilepsy (ILAE) consensus classification system for focal cortical dysplasia in 2011 2, which shares many features with the previously described classification systems by Palmini (2004) and Barkovich (2005).  In 2022, an up...

Calcaneal apophysitis

Calcaneal apophysitis, also known as Sever disease, is the painful inflammation of the apophysis of the calcaneus. Epidemiology It typically presents in active young children and adolescents, especially those who enjoy jumping and running sports.  Associations High plantar foot pressures are...

Developmental venous anomaly

Developmental venous anomaly (DVA), also known as cerebral venous angioma, is a congenital malformation of veins which drain normal brain. They were thought to be rare before cross-sectional imaging but are now recognized as being the most common cerebral vascular malformation, accounting for ~5...

Diffuse astrocytoma grading

Grading of diffuse astrocytic tumors in adults has been done according to a number of systems over the years, although by far the most popular now being the WHO grading system. Historically these grading systems focussed on the presence or absence of a number of histological features, although ...

EWSR1-SMAD3-positive fibroblastic tumor

EWSR1-SMAD3-positive fibroblastic tumors are benign mesenchymal neoplasms with different morphologies and a provisional name 1-4 that was and added to the WHO classification of soft tissue tumors in 2020 2,3. Epidemiology EWSR1-SMAD3-positive fibroblastic tumors are sporadic soft tissue neopla...

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