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.
16,861 results found
Article
Schneiderian papilloma
Schneiderian papillomas, also known as sinonasal papillomas, are benign sinonasal tumors that arise from the Schneiderian epithelium of the nasal cavity and paranasal sinuses.
Epidemiology
Schneiderian papillomas account for ~2.5% (range 0.4-4.7%) of sinonasal tumors 2.
Pathology
The WHO cl...
Article
Contrast-enhanced ultrasound
Contrast-enhanced ultrasound (CEUS) involves the administration of intravenous contrast agents consisting of microbubbles/nanobubbles of gas.
Clinical applications
liver
hepatic metastasis
cystadenoma/cystadenocarcinoma
cholangiocarcinoma
hepatocellular carcinoma
hepatic adenoma
focal no...
Article
Transient hepatic attenuation differences
Transient hepatic attenuation differences (THAD) lesions refer to areas of parenchymal enhancement visible during the hepatic artery phase on helical CT. They are thought to be a physiological phenomenon caused by the dual hepatic blood supply. Occasionally, they may be associated with hepatic t...
Article
Transient hepatic intensity difference
Transient hepatic intensity differences (THID) is a phenomenon observed on MRI imaging of the liver. They are considered a direct equivalent to transient hepatic attenuation differences (THAD) seen with CT and transient hepatic echogenicity differences (THED) with CEUS. They may be focal or non-...
Article
LI-RADS US Surveillance
Liver Imaging Reporting and Data System Ultrasound Surveillance (LI-RADS US Surveillance) is a standardized system with recommendations for imaging technique, interpretation and reporting for surveillance of hepatocellular carcinoma (HCC) using unenhanced ultrasound in patients at high risk for ...
Article
CT/MRI LI-RADS
CT/MRI Liver Imaging Reporting and Data System (LI-RADS) is an algorithm for diagnosing and staging hepatocellular carcinoma (HCC) (CT/MRI Diagnostic LI-RADS) or assessing the response of HCC to locoregional treatment (CT/MRI Treatment Response LI-RADS) using CT or MRI with extracellular contras...
Article
Spinoglenoid notch ganglion cyst
Spinoglenoid notch ganglion cysts are a location-specific form of ganglion cysts that arise in the region of the spinoglenoid notch.
Epidemiology
They are generally rare and may be slightly more common in males 2.
Associations
glenoid labral tears: especially SLAP lesions 5
Clinical present...
Article
Bone marrow
Bone marrow is ubiquitous throughout the skeleton, primarily composed of hematopoietic cells and fat cells between bony trabeculae and fibrous retinacula. It performs numerous physiological functions and dynamically changes during normal aging and in response to stressors and pathology. Although...
Article
Pituitary macroadenoma
Pituitary macroadenomas are the most common suprasellar mass in adults, and responsible for the majority of transsphenoidal hypophysectomies. They are defined as pituitary adenomas greater than 10 mm in size and are approximately twice as common as pituitary microadenomas.
On imaging, they usu...
Article
Sinding-Larsen-Johansson disease
Sinding-Larsen-Johansson disease, also known as Sinding-Larsen disease or Larsen-Johansson syndrome, affects the proximal end of the patellar tendon as it inserts into the inferior pole of the patella. It represents a chronic traction injury of the immature osteotendinous junction. It is a close...
Article
Posterior ciliary arteries
The posterior ciliary arteries are usually paired branches arising from the ophthalmic artery, one medial and one lateral, each giving off a number of branches that supply the uvea 1.
Close to the optic nerve, are the short posterior ciliary arteries, usually numbering 16-20; these supply the p...
Article
Thyroid-associated orbitopathy
Thyroid-associated orbitopathy, also known as thyroid-associated ophthalmopathy or thyroid eye disease, is the most common cause of proptosis in adults and is most frequently associated with Graves disease. On imaging, it is characterized by bilateral and symmetrical enlargement of the extraocul...
Article
Temozolomide
Temozolomide is an oral chemotherapeutic drug primarily used in the treatment of astrocytomas, oligodendrogliomas and glioblastoma, often in conjunction with radiotherapy (Stupp protocol).
Mechanism of action
Temozolomide is an alkylating agent. It adds a methyl group to the purine bases of DN...
Article
Monochorionic monoamniotic twin pregnancy
A monochorionic monoamniotic (MCMA) twin pregnancy is a subtype of monozygotic twin pregnancy. These fetuses share a single chorionic sac, a single amniotic sac, and, in general, a single yolk sac.
Epidemiology
It accounts for the minority (~5%) of monozygotic twin pregnancies and ~1-2% of al...
Article
Medical abbreviations and acronyms (N)
This article contains a list of commonly used medical abbreviations and acronyms that start with the letter N and may be encountered in medicine and radiology (please keep the main list and any sublists in alphabetic order).
A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R ...
Article
Electrical impedance tomography
Electrical impedance tomography (EIT) is a type of imaging based on sending small amounts of electrical current across tissue (when used for medical imaging), and measuring conductivity. Such measurements are done with electrodes around the object measured, and reconstruction algorithms are used...
Article
Infratemporal fossa
The infratemporal fossa is a complex space of the face that lies posterolateral to the maxillary sinus, below the skull base, and between the pharyngeal sidewall and mandibular ramus. It overlaps with the masticator space and prestyloid parapharyngeal space.
Gross anatomy
The infratemporal fos...
Article
Methylguanine-DNA methyltransferase (MGMT)
O6-Methylguanine-DNA methyltransferase (MGMT) is a DNA repair enzyme that is important in predicting the effects of alkylating chemotherapeutic agents (e.g. temozolomide) in the treatment of high-grade gliomas (astrocytomas and glioblastomas).
Mechanism of action
MGMT is an enzyme that removes...
Article
Stupp protocol
The Stupp protocol has become the standard of care for the treatment of high-grade astrocytoma and glioblastoma since its publication in 2005 and has led to significant survival improvements 1. It consists of radiotherapy and concomitant chemotherapy with temozolomide, an alkylating agent.
Prot...
Article
Lipoma
Lipomas are benign tumors composed of mature adipocytes. They are the most common soft tissue tumor, seen in ~2% of the population.
Epidemiology
Patients typically present in adulthood (5th-7th decades).
Associations
In some cases, multiple lipomas are associated with syndromes and other di...