Items tagged “refs”

2,938 results found
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Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS)

Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) is one of many mitochondrial disorders. As mitochondria, which have their own DNA, are exclusively passed on from the mother these disorders are only inherited from the mother. On imaging, it manifests as mult...
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Multiple endocrine neoplasia type II

Multiple endocrine neoplasia type II (MEN2) is also known as mucosal neuroma syndrome or multiple endocrine adenomatosis. It is a collection of syndromes characterized by the presence of multiple endocrine tumors.  They are autosomal dominant in inheritance, and share medullary thyroid carcinom...
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Multiple endocrine neoplasia type IIa

Multiple endocrine neoplasia (MEN) type IIa, also known as Sipple syndrome, accounts for most cases of MEN2 and is characterized by: pheochromocytomas: in 50% of patients, often bilateral, and can be extra-adrenal medullary thyroid cancer: 100% of patients, aggressive, and may secrete calciton...
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MacEwen triangle

The MacEwen triangle (also called the suprameatal triangle or mastoid fossa) is a surgical landmark on the surface of the temporal bone just superior to the external auditory canal used to locate the level of the mastoid antrum. Three lines form the triangle: superior: inferior temporal line/s...
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Malignant vascular tumors

Malignant vascular tumors are rare, accounting for <1% of all sarcomas.  Pathology intermediate grade hemangioendothelioma Kaposi sarcoma high grade hemangiopericytoma angiosarcoma
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Malleus

The malleus (plural: mallei) is the most lateral middle ear ossicle, located between the tympanic membrane and the incus. Gross anatomy The malleus has a head, neck, and three distinct processes (manubrium (handle), anterior and lateral processes). The head is oval in shape, and articulates p...
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Mammography

Mammography is a dedicated radiographic technique for imaging the breast, and the resultant images are known as mammograms. Types of mammography In general terms, there are two types of mammography: screening and diagnostic. Mammography differs significantly in many respects from the rest of ...
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Megalencephaly

Megalencephaly (MEG) is a disorder characterized by an abnormally large brain. It is primarily a proliferative disorder of embryonic origin. It may involve all or part of the cerebral hemispheres and can be bilateral or unilateral. It is often associated with polymicrogyria or agyria.  Terminol...
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Congenital spinal meningocele

Congenital spinal meningoceles are developmental anomalies of meningothelial elements displaced into the skin and subcutaneous tissues. Please refer to the meningocele article for a broad overview of all types of this condition.  Pathology It is a defect of the neural tube, an embryonic struc...
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Middle ear effusion

Middle ear effusions are frequent in children due to prominent adenoids and horizontal Eustachian tubes. These do not require imaging and can be treated expectantly / medically / surgically with tympanostomy tubes. Eustachian tube dysfunction is the accepted etiology, with resorption of air and ...
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Middle ear granulation tissue

Development of granulation tissue in the middle ear cavity is a generalized response to injury/inflammation, chronic otomastoiditis. It can either be typical or go down the pathway of becoming a cholesterol granuloma. Radiographic features Typical granulation tissue is common, more so than cho...
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Middle lobe bronchiectasis

Middle lobe bronchiectasis is an imaging an imaging descriptor when bronchiectasis is confined to the middle lobe. When it (predominantly) involves the middle lobe it is sometimes is termed right middle lobe predominant (RMLP) bronchiectasis 2. Middle lobe bronchiectasis may be seen in: non-tu...
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Multilayered periosteal reaction

Multilayered periosteal reaction, also known as a lamellated or onion skin periosteal reaction, demonstrates multiple concentric parallel layers of new bone adjacent to the cortex, reminiscent of the layers on an onion. The layers are thought to be the result of periods of variable growth 2 and ...
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Muscles of the tongue

The muscles of the tongue are divided into 2 groups each comprising 4 muscles. They are classified as intrinsic (to the tongue) and extrinsic muscles. They allow for the complex movements of the tongue and are all innervated by the hypoglossal nerve (CN XII) except one:​ intrinsic muscles of th...
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Myelitis

Myelitis is a collective term simply referring to any inflammation of the spinal cord. It is a form of myelopathy. The two major sub types include: leukomyelitis multiple sclerosis ADEM transverse myelitis ideopathic transverse myelitis secondary transverse myelitis: viral, neurosyphilis ...
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Myoepithelioma

Myoepitheliomas and malignant myoepitheliomas were considered a variant of pleomorphic adenomas until 1991. However, these are also found in breast and bronchus and have gained recognition as separate entities. They account for less than 1% of salivary gland tumors, only rarely undergo malignant...
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Midline nasal region lesions

A variety of congenital midface anomalies occur in children. Although rare, these disorders are clinically important because of their potential for connection to the central nervous system. Lesions presenting as a midline nasal mass include: nasal glioma nasal encephalocele nasal dermoid cyst...
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Nephrocalcinosis

Nephrocalcinosis, previously known as Anderson-Carr kidney or Albright calcinosis, refers to the deposition of calcium salts in the parenchyma of the kidney. It is divided into several types, with differing etiologies, based on the distribution: medullary nephrocalcinosis: 95% cortical nephroc...
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Nerve to stapedius

The nerve to stapedius arises from the facial nerve to supply the stapedius muscle. The branch is given off in the facial nerve's mastoid segment, as it passes posterior to the pyramidal process. Damage to this branch with resulting paralysis of stapedius leads to hypersensitivity to loud noise...
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Nottingham classification

The Nottingham classification is used at the end of work up of a breast lesion to help guide management. A = malignant lesion needs surgical excision regardless of biopsy result B = indeterminate will accept a benign biopsy result, but only if it is congruent with imaging, i.e. a well circum...