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 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.

67 results found
Article

Submandibular gland enlargement

Submandibular gland enlargement refers to an increase in the volume of the submandibular gland, exceeding "normal" values of 7.4 ± 1.8 mL 1. Pathology Causes Obstruction sialolithiasis submandibular duct stenosis (e.g. tumor, granulomatous disease) Infection acute sialadenitis: following ...
Article

Optic nerve calcification

Optic nerve calcification is a rare radiological finding, with only a short differential diagnosis, many of which have only been described in isolated case reports 1-4. Differential diagnosis optic nerve meningioma optic nerve head drusen idiopathic dural optic nerve sheath calcification ca...
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Leave alone lesions - maxillodental

Maxillodental leave alone lesions are usually incidental findings that do not require treatment nor follow-up if the patient is asymptomatic. This article includes findings from orthopantomogram, cone-beam CT, and sinus CT studies. Do not touch: benign lesions tooth ankylosis hypercementosi...
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Leave alone lesions - skull base

Leave alone lesions of the skull base refers to incidental findings that do not require treatment nor follow-up. This article includes findings from brain CT, HRCT of the temporal bone, and MRI studies. Do not touch: arrested pneumatization of the skull base - sphenoid benign fatty lesion 1 ...
Article

Leave alone lesions - paranasal sinuses

Leave alone lesions are findings that are usually discovered incidentally and do not require any specific treatment or follow-up if the patient is asymptomatic. This article includes findings from paranasal sinus CT and MRI studies. physiological process nasal cycle anatomical variants conc...
Article

Epiglottic enlargement

Epiglottic enlargement is often seen on lateral neck radiographs and it's accepted to confirm clinical suspicion of acute epiglottitis only on this finding 1. However, an enlarged epiglottitis has a wide range of differentials that should be considered. neoplasm hemangioma lymphangioma carci...
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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

Periapical radiolucency (teeth)

Periapical radiolucencies are commonly observed findings on OPG and other dental/head and neck imaging modalities. Differential diagnosis They can represent a number of pathologies: periapical lucency related to apical periodontitis periapical granuloma periapical abscess periapical cyst ...
Article

Calcific cervical lymphadenopathy (differential)

Calcific cervical lymphadenopathy is uncommon and has a limited differential diagnosis, including malignant and benign etiologies. The most frequent causes include 1: malignancies (more common) metastatic thyroid carcinoma (most common; papillary or medullary types) 2,5 metastatic adenocarcin...
Article

Lacrimal sac mass

Lacrimal sac masses are very uncommon and more commonly have a malignant (~80%) rather than benign (~20%) etiology.  Pathology Etiology inflammatory granulomatosis with polyangiitis sarcoidosis orbital pseudotumor IgG4-related disease Sjogren syndrome neoplastic epithelial tumors beni...
Article

Mastoid air cell opacification

Mastoid air cell opacification can occur in a number of situations and can include a spectrum of inflammatory, neoplastic, vascular, fibro-osseous, and traumatic changes. Possible causes include: otomastoiditis acute otomastoiditis chronic otomastoiditis radiation 3 trauma (temporal bone f...
Article

Epiphora

Epiphora (plural: epiphoras) represents excessive tearing of the eye and is a common clinical presentation to ophthalmological practice. It is most frequently due to an obstruction of the nasolacrimal drainage apparatus. Less commonly, overproduction of tears may be responsible.  Epidemiology ...
Article

Pediatric nasal cavity masses

Pediatric nasal cavity masses can occur within the nose or the nasopharynx. These masses are often found incidentally on imaging but can be readily apparent clinically. Clinical presentation The clinical features of these lesions tend to mimic upper respiratory processes and may result in dela...
Article

Hypoglobus

Hypoglobus refers to the inferior displacement of the globe in the orbit. It may or may not be associated with enophthalmos. Causes include: fracture of the orbital floor (most common) silent sinus syndrome orbital masses orbital foreign bodies thyroid ophthalmopathy
Article

Calcification of the external ear (differential)

Calcification of the external ear (auricular cartilage) may arise from a number of causes, including: hyperparathyroidism gout and pseudogout relapsing polychondritis frostbite trauma ochronosis sarcoidosis diabetes mellitus adrenal insufficiency osteoprotegerin (OPG)-deficiency juveni...
Article

Intrasinus calcification

Intrasinus calcification is a phenomenon whereby calcification is formed within the paranasal sinuses. It can occur to varying extents, therefore leading to varying degrees of attenuation on CT. Such calcification may occur either concurrently within an opacified sinus or in an aerated sinus, de...
Article

Congenital calvarial defects

Congenital calvarial defects are a group of disorders characterized by congenital calvarial bone defects that vary in severity. Radiographic features CT with 3D shaded surface reformats is the best imaging tool as it demonstrates calvarial defects and bone margins: parietal foramina parietal...
Article

Focal calvarial thinning

Focal calvarial thinning can result from a number of causes. They include: bilateral thinning of the parietal bones (normal variant) most common arachnoid cyst mega cisterna magna peripherally located tumors (e.g. oligodendroglioma) See also calvarial thinning calvarial thickening
Article

Hyperattenuating paranasal sinus opacification

Hyperattenuating paranasal sinus opacification can arise in a number of situations: fungal sinus disease inspissated secretions acute hemorrhage into sinus (hemosinus) Differential diagnosis In some situations can consider early calcification within the sinus - intrasinus calcification.
Article

Obstruction of nasolacrimal drainage apparatus

Obstruction of nasolacrimal drainage apparatus results in epiphora and can be primary or secondary, congenital or acquired. Obstruction can occur at canalicular, lacrimal saccular, or nasolacrimal ductal (post-saccular) levels. Causes of obstruction Congenital obstruction persistence of the m...
Article

Mandibular periostitis

There are many causes for mandibular periostitis: Langerhans cell histiocytosis malignancy (both primary and metastatic) necrosis, e.g. radiation osteonecrosis osteomyelitis pyogenic Garre's sclerosing osteomyelitis actinomycosis (uncommon) syphilis (uncommon) tuberculosis (uncommon) r...
Article

Valsalva maneuver

The Valsalva maneuver is the forced expiration of air against a closed airway, resulting in increased intra-abdominal, intrathoracic, and pharyngeal pressure. It can be performed against a closed glottis or by one closing the mouth and pinching the nose while forcibly exhaling. It is commonly u...
Article

Torticollis

Torticollis, also known as wry neck, is a clinical finding of head tilt with or without rotational spinal malalignment. It is not a diagnosis in itself and there are a wide range of underlying conditions. It is most common in the pediatric age group.  Pathology Torticollis can be acute (<1 wee...
Article

Medical devices in the head and neck

Medical devices in the head and neck are regularly seen by radiologists on plain film, CT and MRI. They include devices which pass through the neck into the chest and stomach or ascend to/into the head. Vascular access devices dialysis catheters peripherally inserted central catheters (PICC) ...
Article

Enlarged extraocular muscles (differential)

There is a short list of causes for enlarged extraocular muscles. The differential can be narrowed by the clinical history, known systemic illness, pattern of specific muscles involved, the muscle morphology, as well as concurrent findings outside the muscles 3: inflammatory, infectious, and de...
Article

Jugular fossa masses

Jugular fossa masses comprise a range of pathological lesions that arise from or extend into the jugular fossa in the skull base. Although not a common location for tumors it is not unusual for jugular fossa lesions to be discovered incidentally on cross-sectional imaging. Terminology Although...
Article

Orbital cystic lesions

Several cystic and cyst-like orbital lesions may be encountered in imaging of the orbits: developmental orbital cysts choristoma dermoid: commonest benign orbital tumor in childhood  epidermoid teratoma  congenital cystic eye colobomatous cyst acquired abscess hematoma lacrimal gland ...
Article

Extraconal orbital lesions

Extraconal orbital lesions include lesions which arise from structures within the extraconal orbital space and those extending from adjacent structures into the orbits. Differential diagnosis Intraorbital lesions dermoid cyst: most common lesion in pediatrics  lacrimial gland lesions dacryo...
Article

Intraconal orbital lesions

Intraconal orbital lesions are broadly divided into two main groups; those with or without involvement of the optic nerves. Lesions with optic nerve involvement: optic nerve glioma optic nerve meningioma optic neuritis pseudotumor lymphoma and leukemia intracranial hypertension retinobla...
Article

Developmental orbital cysts

Developmental orbital cysts correspond to a heterogeneous group of congenital orbital developmental anomalies with a cystic component, ranging from closed sacs lined by an ectodermal epithelium, such as epidermoid and dermoid, to neoplasms such as teratoma 1: choristoma: benign tumors formed by...
Article

Telecanthus

Telecanthus (rare plural: telecanthi) represents an increased intercanthal distance. It is often used interchangeably with hypertelorism, referring to increased distance between the eyes. Causes and associations trauma: naso-orbitoethmoidal (NOE) fractures ethnic variation acquired sinus an...
Article

Heterogeneous thyroid echotexture

Heterogeneous echogenicity of the thyroid gland is a non-specific finding and is associated with conditions diffusely affecting the thyroid gland. These include: Hashimoto thyroiditis Graves disease The presence of heterogenous thyroid echogenicity may reduce sensitivity of detection of thyro...
Article

Pulsatile exophthalmos

Pulsatile exophthalmos, a.k.a. pulsatile proptosis, is a clinical symptom characterized by protrusion - i.e. exophthalmos (proptosis) - and pulsation of the eyeball that can occur due to various causes: caroticocavernous fistulas neurofibromatosis type 1 (with sphenoid wing dysplasia) 2 arter...
Article

Vestibular line of Lapayowker

The vestibular line of Lapayowker refers to a vertical line passing down the most lateral aspect of vestibular apparatus. The petrous part of internal carotid artery lies medial to this line but lies lateral to it in the case of an aberrant internal carotid artery which is the characteristic ang...
Article

Wackenheims line

Wackenheims line (also known as the clivus canal line or basilar line) is formed by drawing a line along the clivus and extending it inferiorly to the upper cervical canal. Normally the tip of the dens is ventral and tangential to this line. In basilar invagination odontoid process transects th...
Article

Proptosis

Proptosis (rare plural: proptoses) refers to forward protrusion of the globe with respect to the orbit. Proptosis can be relative (to the contralateral eye), comparative (to a prior measurement of the same eye), or absolute (based on normal population reference values). Terminology Exophthalmo...
Article

Frontal bossing

Frontal bossing is a calvarial radiographic feature where the front of the skull appears protruding anteriorly. It is best appreciated on a sagittal or lateral image. Pathology This feature can be seen in many conditions (in alphabetical order): 18q syndrome acromegaly achondroplasia ß-tha...
Article

Cystic mass adjacent to the angle of mandible (differential)

The differential diagnosis of a cystic mass adjacent to the angle of mandible includes: 2nd branchial cleft cyst lymphatic malformation (lymphangioma) cystic lymphadenopathy from tuberculosis from metastatic squamous cell carcinoma  from metastatic papillary thyroid cancer See also cys...
Article

Hypotelorism

Hypotelorism refers to an abnormal decrease in distance between any two organs although some authors use the term synonymously with orbital hypotelorism meaning an abnormal decrease in the distance between the two eyes (the eyes appear too close together). The article mainly focuses on the latte...
Article

Differential diagnosis for calcified masses in the mandible

Differential diagnosis for calcified masses in the mandible includes: calcifying odontogenic cyst (Gorlin cyst) calcifying epithelial odontogenic tumor (Pindborg tumor) fibrous dysplasia foreign body odontoma cemento-ossifying fibroma osteoma synovial osteochondromatosis focal sclerosi...
Article

Lacrimal gland masses

Lacrimal gland masses​ can be classified into two broad groups - inflammatory (~50%) and neoplastic, either lymphoma (25%) or salivary gland type tumors (~25%).  Pathology Inflammatory sarcoidosis affects ~25% of patients with systemic disease orbital inflammatory pseudotumor lacrimal glan...
Article

Adult cervical lymphadenopathy (differential)

Cervical lymphadenopathy in an adult can result from a vast number of conditions. They include: malignancy metastases  from head and neck tumors lymphoma other neoplastic lesions Castleman disease Kaposi sarcoma infection bacterial infection viral infection Epstein-Barr virus herpes ...
Article

Petrous apex lesions (differential)

There is a wide differential diagnosis of petrous apex lesions: pseudolesions asymmetrical marrow/asymmetrical pneumatization non-expansile fat signal intensity on all sequences simple effusion petrous apex cephalocele 4 CSF signal intensity on all sequences petrous apicitis congenital ...
Article

Ocular metastasis

Ocular metastases, also termed uveal metastases, account for over 80% of all ocular pathology, and need to be distinguished from extraocular metastasis, which are quite different groups of tumors. This article will discuss metastatic lesions affecting the orbits. For other intracranial metastat...
Article

Ocular pathology

Ocular pathology covers a wide range of conditions and therefore represents the cause of a wide range of symptoms, signs and radiographic features. Ocular metastases account for over 80% of all ocular pathology. With regard to the remainder of ocular lesions, the primary differentiating factor ...
Article

Parotid gland enlargement

Parotid gland enlargement (also known as parotidomegaly) has a wide differential given the significant breadth of pathology that can affect the parotid gland. These can be separated by a standard surgical sieve approach into infective, inflammatory, immune, neoplastic, infiltrative, and congenit...
Article

Ophthalmoplegia

Ophthalmoplegia describes the abnormal eye movement that occurs because of paralysis of one or more of the six extraocular muscles involved in eye movements. Classification can be based on the cause of the ophthalmoplegia or the directions of the affected movements. There are numerous causes of...
Article

Orbital vascular lesions

Orbital vascular lesions may be difficult to distinguish on imaging. However, the following conditions have been described: arteriovenous malformation (AVM) capillary hemangioma cavernous hemangioma orbital lymphangioma / lymphangiovenous malformation / venolymphatic malformation orbital ve...
Article

Pediatric cervical lesions (differential)

The differential diagnosis of pediatric cervical lesions is commonly encountered in practice, unfortunately, the list is long. Differential diagnosis Inflammatory Most lesions tend to be inflammatory 3: non-tuberculous mycobacterial lymphadenitis scrofula sialodochitis abscess infected ...
Article

Dysphagia

Dysphagia refers to subjective awareness of difficulty or obstruction during swallowing. It is a relatively common and increasingly prevalent clinical problem. Odynophagia is the term for painful swallowing. Fluoroscopy is the mainstay of imaging assessment but manometry can help evaluate the e...
Article

Optic nerve enlargement

Enlargement of the optic nerves is uncommon. Swelling of the optic nerves has a surprisingly broad differential. Etiology neoplastic optic nerve glioma optic nerve meningioma leukemia orbital lymphoma metastases juvenile xanthogranuloma medulloepithelioma involvement by retinoblastoma ...
Article

Meckel cave lesions (differential)

Meckel cave lesions are numerous. The aim of this article is to list them in an easy way for revision and assessment of differential diagnosis.  Neoplastic Meckel cave tumors account for only 0.5% of all intracranial tumors. The most common histologies are: trigeminal schwannoma: most common,...
Article

Midline neck mass

Midline neck masses have a relatively narrow differential, as few structures are present in the midline. Dividing the causes according to structure of origin is a useful schema. lymph node(s): Delphian node(s) inflammatory adenopathy malignancy thyroid gland thyroglossal duct cyst thyroid ...
Article

Temporomandibular joint effusion

Temporomandibular joint (TMJ) effusions are unusual in asymptomatic patients, and thus should trigger a careful search for underlying pathology. It usually precedes osteoarthritis of the TMJ. Effusions are seen in: TMJ dysfunction septic arthritis rheumatoid arthritis (RA) Radiographic featu...
Article

Skull tumors

Skull tumors can be (as with tumors anywhere else) both primary and secondary, and benign or malignant. Primary Benign osteoma ossifying fibroma osteoblastoma hemangioma giant cell tumor (GCT) aneurysmal bone cyst (ABC) epidermoid and dermoid cysts chondroma Malignant osteosarcoma c...
Article

Pedunculated intratracheal mass

A pedunculated intratracheal mass has a variety of differential diagnoses: benign tumor, e.g. hamartoma, chondroma, lipoma hemangioma inspissated mucus metastasis to tracheal mucosa, e.g. renal cell carcinoma, melanoma polyp, e.g. inflammatory, antrochoanal papilloma post-intubation trach...
Article

Orbital mass

An orbital mass carries a wide differential. Differential diagnosis tumors lymphoma metastasis lacrimal gland or duct tumors rhabdomyosarcoma of the orbit retinoblastoma optic nerve meningioma optic nerve glioma schwannoma (of trigeminal or other cranial nerves except optic) neurofibr...
Article

Clival masses

The differential of a mass involving or arising from the clivus is a relatively narrow one and can be divided into whether the lesion arises from the skull base itself, the intracranial compartment above or the base of skull below. When evaluating the clivus it is important to compare the marro...
Article

Macrophthalmia

The increased globe size or macrophthalmia may have many differentials: buphthalmos (congenital glaucoma) axial myopia macrophthalmus in neurofibromatosis type 1 (NF1) connective tissue disorders: Marfan syndrome, Ehlers-Danlos syndrome Focal enlargement: staphyloma coloboma See also mi...
Article

Salivary gland tumors

Salivary gland tumors are variable in location, origin, and malignant potential.  Pathology In general, the ratio of benign to malignant tumors is proportional to the gland size; i.e. the parotid gland tends to have benign neoplasms, the submandibular gland 50:50, and the sublingual glands and...
Article

Middle ear tumors

There are a range of middle ear tumors, which are more likely to be benign than malignant.  Pathology The three most common middle ear tumors are (not in any particular order as there are differences in the literature) 1-3:  glomus tympanicum paraganglioma congenital cholesteatoma middle ea...
Article

Mandibular lesions

Mandibular lesions are myriad and common. The presence of teeth results in lesions that are specific to the mandible (and maxilla) and a useful classification that defines them as odontogenic or non-odontogenic. While it may often not be possible to make a diagnosis on imaging alone, this classi...
Article

Hyperostosis of the skull (differential)

Hyperostosis of the skull has many causes, broadly divided into focal or diffuse. Diffuse Paget disease of bone metastatic disease, especially prostate carcinoma chronic, severe anemia hyperparathyroidism acromegaly osteopetrosis hyperostosis frontalis interna long-term phenytoin use g...
Article

Cystic (necrotic) lymph nodes

Cystic or necrotic appearing lymph nodes can be caused by a number of infectious, inflammatory or malignant conditions: Systemic squamous cell carcinoma metastases treated lymphoma leukemia plasmacytoid T-cell leukemia acute myeloid leukemia viral lymphadenitis herpes simplex lymphadenit...
Article

Multiple cystic neck lesions (differential)

The differential diagnosis for multiple cystic neck lesions is different to that for a solitary cystic neck mass. Differential diagnosis Cystic neck lesions are seen in: metastatic squamous cell carcinoma: older patient, M>F metastatic papillary thyroid carcinoma: usually a younger patient, ...
Article

Cystic parotid lesions

The differential for cystic parotid lesions includes: bilateral cystic parotid lesions Warthin tumor benign lymphoepithelial lesions of HIV Sjögren syndrome sialoceles dysgenetic polycystic disease of salivary glands unilateral cystic parotid lesion(s) Warthin tumor sialocele first bra...
Article

Calcification of the globe (differential)

Calcification of the globe has many causes, varying from the benign to malignant. When calcification is seen of the posterior half of the globe, it could relate to any of the layers (scleral, choroidal or retinal), as it is not possible to separate them out on CT. Retinal drusen: 1% population...

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