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.
782 results found
Article
Dural enhancement
Pachymeningeal enhancement, also known as dura-arachnoid enhancement 4, refers to a dural and outer layer of arachnoid pattern of enhancement seen following contrast administration and may occur in the conditions listed below:
infection
intracranial tumor
metastases (meningeal carcinomatosis-...
Article
Dural masses
Dural masses can be the result of a number of different tumors and conditions, although meningiomas are by far the most common. The differential of a dural mass includes:
meningioma
hemangiopericytoma
primary dural lymphoma
Rosai-Dorfman disease
solitary fibrous tumor of the dura
primary i...
Article
Dynamic tracheal collapse
Dynamic tracheal collapse refers to collapse of the trachea during expiration. It is perhaps best assessed on CT in the end expiratory phase. An inspiratory series is also useful for comparative purposes. The term excessive dynamic airway collapse (EDAC) refers to abnormal and exaggerated bulgin...
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
Dystrophic soft tissue calcification
Dystrophic soft tissue calcification is a type of soft-tissue calcification, which occurs in damaged or necrotic tissue, while the serum level of calcium and phosphorus are normal. It may progress to ossification, in which case a cortical and trabecular bone pattern is visible.
An often cited a...
Article
Echogenic fetal lung lesions
Echogenic fetal lung lesions on antenatal ultrasound can be detected in a number of situations. They include:
Airway obstructions: lung are often enlarged and echogenic bilaterally
congenital high airways obstruction syndrome (CHAOS)
tracheal atresia
congenital tracheal stenosis
laryngeal a...
Article
Echogenic renal pyramids (differential)
Echogenic renal pyramids in children can be due to many different causes.
Differential diagnosis
Nephrocalcinosis
Iatrogenic (most common cause)
furosemide (frusemide)
vitamin D
steroids
Non-iatrogenic
idiopathic hypercalcemia
Williams syndrome
hyperparathyroidism
milk-alkali syndrom...
Article
Elevated diaphragm
Elevated diaphragm refers to the symmetrical elevation of both domes of the diaphragm.
Pathology
Etiology
There is some overlap with causes of an elevated hemidiaphragm.
Technical
supine position
poor inspiratory effort
Patient factors
obesity
pregnancy
Diaphragmatic pathology
paral...
Article
Elevated hemidiaphragm
An elevated hemidiaphragm may result from direct and indirect causes which include:
above the diaphragm 1
decreased lung volume
atelectasis/collapse
prior lobectomy or pneumonectomy
pulmonary hypoplasia
diaphragm 3-7
phrenic nerve palsy
diaphragmatic eventration
contralateral stroke: ...
Article
Elevated prolactin (differential)
Elevated prolactin can be due to a number of causes, including elevated production/secretion as well as reduced inhibition.
Prolactin is controlled by numerous homeostatic mechanisms, with tonic secretion of prolactin inhibitory hormone (dopamine) by the hypothalamus having a dominant effect 1...
Article
Empty gestational sac
Empty gestational sacs can be due to a number of causes:
anembryonic pregnancy (also known as "blighted ovum")
early pregnancy (intrauterine): by 5.5 weeks gestational age, a yolk sac should be identifiable by transvaginal ultrasound
pseudogestational sac with an ectopic pregnancy
gestationa...
Article
Empyema
Empyemas are purulent inflammatory collections within a body cavity. Contrast this with abscesses, which arise within parenchymal tissue, rather than occupying a pre-existing anatomical space.
Terminology
Colloquially, the standalone term empyema is used to refer to thoracic empyemas but there...
Article
Encephalitis due to herpesvirus family
Although sporadic viral encephalitis is most commonly due to herpes simplex virus 1 (HSV-1) the extended herpesvirus family consists of many other viruses many of which can also infect the central nervous system. Encephalitis due to herpesvirus family include 1:
herpes simplex virus 1 (HSV-1)...
Article
Endobronchial metastases
Endobronchial metastases are an uncommon form of intrathoracic metastases. They are much less common than intrapulmonary metastases.
Clinical presentation
The clinical presentation varies and includes:
hemoptysis
cough
post-obstructive pneumonitis from distal obstruction
Pathology
Frequen...
Article
Endometrial fluid
Fluid in the endometrial cavity can result from a number of causes if excessive and associated with distension.
Pathology
There are essentially three types of fluid:
hydrometra: simple fluid
hematometra: hemorrhagic content / clot
pyometra: pus
Premenopausal
normal (i.e. physiological)
...
Article
Endometrial microcalcifications
Endometrial microcalcifications can arise from a vast range pathologies but are usually of benign in etiology.
Epidemiology
They have an increased incidence with older age, postmenopausal state, atrophic endometrium, and endometrial polyps.
Associations
In some cases they are associated wit...
Article
Endosteal scalloping
Endosteal scalloping refers to the focal resorption of the inner layer of the cortex (i.e. the endosteum) of bones, most typically long bones, due to slow-growing medullary lesions.
It is important to note that although it is evidence of a slow non-infiltrative lesion, it does not equate to ben...
Article
Enlarged azygos vein
An enlarged/dilated azygos vein may result from a number of physiological as well as pathological causes. The enlarged azygos vein may be seen as a widened right paratracheal/paraspinal stripe on a frontal chest radiograph.
Terminology
Spelling it "azygous" when referring to the vein is incorr...
Article
Enlarged echogenic fetal kidneys
Enlarged echogenic fetal kidneys can be associated with a number of pathologies that include:
autosomal recessive polycystic kidney disease (ARPKD) 1
autosomal dominant polycystic kidney disease (ADPKD) 3: the large cysts may not form in utero and the kidneys may initially appear as enlarged a...
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
Enlarged posterior fossa 'CSF' space
An enlarged posterior fossa 'CSF' space posterior to the cerebellum has a number of differentials that include:
mega cisterna magna
epidermoid cyst
arachnoid cyst
Careful attention to the cerebellum needs to paid as also to be considered are:
cerebellar atrophy
Dandy-Walker malformations
...
Article
Enlarged pulmonary trunk on chest radiography (differential)
The differential of an enlarged pulmonary trunk/main pulmonary artery on chest radiography includes:
normal
may appear prominent in young patients especially women
projectional
rotation
lordotic view
rotation of the heart
pectus excavatum
left lower lobe collapse
pulmonary arterial hyp...
Article
Enlarged sella turcica (differential)
Enlargement of sella turcica can be seen in situations including the following:
empty sella syndrome
slight globular enlargement of the sella with no erosion, destruction or posterior displacement of dorsum sellae
intracranial hypertension
enlargement with erosion of anterior cortex of dorsu...
Article
Enlargement of the cardiac silhouette
Enlargement of the cardiac silhouette on a frontal (or PA) chest x-ray can be due to a number of causes 1:
cardiomegaly (most common cause by far)
pericardial effusion
anterior mediastinal mass
prominent epicardial fat pad
expiratory radiograph
AP projection (e.g supine radiographs taken w...
Article
Enteritis
Enteritis (plural: enteritides) refers to inflammation of the small bowel. When associated with inflammation of the stomach, the term gastroenteritis is used which is usually caused by infection.
Pathology
Etiology
infection
infective enteritis
eosinophilic enteritis
ischemia
inflammatory...
Article
Epididymal calcification
Epididymal calcification can be seen on ultrasound as hyperechoic foci within the epididymal head. If the calcifications are large enough, then they may demonstrate acoustic shadowing.
Differential diagnosis
chronic epididymitis, e.g. bacterial, granulomatous (TB) or genital filariasis
traum...
Article
Epididymal lesions
Epididymal lesions are most commonly encountered on ultrasonography. Most epididymal lesions are benign; malignant lesions are rare.
They can comprise of
Benign solid lesions
adenomatoid tumor of the scrotum: most common epididymal mass 4
epididymal leiomyoma
papillary cystadenoma of the e...
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...
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
Epiphyseal lesions (differential)
Epiphyseal lesions comprise tumors and other pathologies that occur around the epiphysis and any epiphyseal equivalent bone.
Differential diagnosis
Common differential diagnoses include the following 2-4:
chondroblastoma: rare epiphyseal tumor found in young adults; it usually does not extend...
Article
Epithelial ovarian tumors
Ovarian epithelial tumors account for the majority of all ovarian tumors (60-70%) and their malignant forms represent >90% of ovarian cancers 1. They can range from being benign to highly malignant.
Epidemiology
There is a difference in frequency of ovarian tumor subtypes depending on menopaus...
Article
Erlenmeyer flask deformity
Erlenmeyer flask deformity (EFD), also known as metaphyseal flaring, refers to a radiographic appearance typically on a femoral radiograph demonstrating relatively reduced constriction of the diaphysis and flaring of the metaphysis as a result of undertubulation.
The name refers to the resembl...
Article
Erosion of superior aspects of ribs (differential)
Differential diagnosis of erosion of the superior aspects of the ribs include:
hyperparathyroidism
rheumatoid arthritis
scleroderma
neurofibromatosis
poliomyelitis
progeria
Article
Erosion of the odontoid process (differential)
Erosion of the odontoid peg can result from a number of pathological entities:
inflammatory arthropathy
rheumatoid arthritis: classic 1,2
systemic lupus erythematosus
crystal arthropathy
calcium pyrophosphate arthropathy (CPPD): relatively common
gout
non-inflammatory arthropathy: osteoar...
Article
Erosive arthritis (differential)
Erosive arthritis has a broad differential:
erosive osteoarthritis
clinically an acute inflammatory attacks (swelling, erythema, pain) in postmenopausal woman
typically the interphalangeal joints, 1st carpometacarpal joint 6, but not the metacarpophalangeal (MCP) joints and large joints
clas...
Article
Exophytic hepatic mass
Exophytic hepatic mass or tumor is a lesion which predominantly lies outside the margins of liver but originates from within the liver.
Pathology
Causes include 1:
benign
hepatic hemangioma
hepatic adenoma
hepatic cyst
hepatic angiomyolipoma
focal nodular hyperplasia
malignant
hepati...
Article
Exostosis
Exostoses are defined as benign growths of bone extending outwards from the surface of a bone. It can occur in any bone and be triggered by a number of factors. There are a number of examples of exostoses that occur due to local irritant stimuli:
ivory exostosis
exostosis of the external audit...
Article
Expansile lytic lesions without cortical destruction of bone (differential)
Expansile lytic bone lesions without cortical destruction can result from various benign and malignant neoplastic pathologies, causes include 1:
unicameral bone cyst
aneurysmal bone cyst (eccentric)
enchondroma
chondromyxoid fibroma (eccentric)
non-ossifying fibroma (eccentric)
desmoplasti...
Article
Extra-axial masses (differential)
Extra-axial masses of the intracranial compartment have a wide range of differentials, ranging from benign developmental cysts to malignant tumors.
Differential diagnosis
neoplasms
chordoma
choroid plexus papilloma/carcinoma
cranial nerve schwannoma
meninges
meningioma
solitary fibrous ...
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
Extraneural spread of intracranial neoplasm
Extraneural spread of primary intracranial neoplasm is distinctly uncommon, occurring far less frequently than CSF spread.
The most frequent neoplasms to do so, in decreasing order of frequency, are:
glioblastoma (GBM)
meningioma
medulloblastoma
Article
Extraskeletal musculoskeletal lesions by compartment
Knowing extraskeletal musculoskeletal lesions by compartment is useful to help generate a meaningful differential diagnosis:
Intermuscular
extraskeletal myxoid chondrosarcoma
fibromatosis
ganglion
leiomyosarcoma
nodular fasciitis
neurogenic tumors
synovial cyst
Intra-articular
lipoma a...
Article
Extratesticular cystic lesions (differential)
The differential diagnosis for extratesticular cystic lesions includes:
hydrocele
epididymal cyst
spermatocele
hematoma
hematocele
loop of bowel from an inguinal hernia
abscess
pyocele
post-vasectomy
varicocele
Very rarely, a scrotal mesothelioma may present as a cystic mass.
Article
Extratesticular scrotal mass (differential)
Extratesticular scrotal masses (non-testicle and non-epididymis) are mostly mesenchymal in origin and benign 1.
Benign lesions
lipoma (most common)
leiomyoma of the scrotum
neurofibroma
granular cell tumor
angiomyofibroblastoma-like tumor
fibrous pseudotumor
fibrous hamartoma of infancy...
Article
Facial palsy
Facial palsy refers to the neurological syndrome of facial paralysis. It can result from a broad range of physiological insults to the facial nerve or its central nervous system origins. The most common causes of this is Bell palsy.
Terminology
While facial palsy refers to the clinical presen...
Article
Failed early pregnancy
Failed early pregnancy refers to the death of the embryo and therefore, miscarriage. The most common cause of embryonic death is a chromosomal abnormality.
Radiographic features
Ultrasound
Findings diagnostic of pregnancy failure
crown-rump length (CRL) of ≥7 mm and no heartbeat on a transva...
Article
Fat containing brain lesions
Intracranial fat is uncommon and a wide range of differentials should be considered.
Neoplastic
intracranial dermoid cyst
intracranial teratoma
intracranial lipoma
pericallosal lipoma
quadrigeminal cistern lipoma
suprasellar cistern lipoma
cerebellopontine angle lipoma
choroid plexus li...
Article
Fat containing breast lesions
Fat containing breast lesions generally have some radiolucent component on mammography.
Pathology
They are generally classified at BIRADS II lesions.
Common
breast lipoma
breast hamartoma
fat necrosis within the breast/oil cyst
intramammary lymph node: classically has a central fatty hilu...
Article
Fat containing cardiac lesions
Fat containing cardiac lesions have a limited differential diagnosis. These include 1-4:
normal aging/physiologic: mostly subepicardial, more in the right ventricle (especially right ventricular outflow tract) than left ventricle
lipomatous hypertrophy of the interatrial septum
chronic myocar...
Article
Fat containing liver lesions
Fat containing liver lesions represent a variety of benign and malignant liver lesions may contain macroscopic and/or intracytoplasmic fat in sufficient quantities enabling characterization on imaging studies. Most fat-containing liver lesions (80%) in patients with cirrhosis are malignant, most...
Article
Fat containing renal lesions
There are numerous fat-containing renal lesions, including:
renal angiomyolipoma
renal cell carcinoma (often has calcifications when contains macroscopic fat)
Wilms tumor
renal oncocytoma
renal or perirenal lipoma/liposarcoma
Non-mass lesions may also occasionally contain fat:
renal junct...
Article
Fat containing solitary pulmonary nodule
The differential of a fat containing solitary pulmonary nodule is very narrow.
In a well circumscribed smooth or lobulated mass (especially if it has been largely stable in size over time) presence of fat is essentially pathognomonic of a pulmonary hamartoma, and usually not further assessment ...
Article
Fat containing thoracic lesions
There is a long list of fat containing thoracic lesions. They may involve the mediastinum, lung, pleura or chest wall.
Differential diagnosis includes:
intrapulmonary: fat containing pulmonary lesions
pulmonary hamartoma
endobronchial lipoma
intrapulmonary lipoma
lipoid pneumonia
myeloli...
Article
Fatty mediastinal masses (differential)
Fatty mediastinal masses are relatively uncommon, and the differential diagnosis is brief, including 1-4:
lipoma
liposarcoma
thymolipoma
benign mature teratoma
lipoblastoma
extravasation of lipid-rich hyperalimentation fluid 3
fibrofatty replacement of the central portion of mediastinal l...
Article
Fetal anterior abdominal wall defects
Fetal anterior abdominal wall defects can occur with a number of pathologies.
Individual entities
omphalocele
gastroschisis
cloacal exstrophy
bladder exstrophy
Syndromes/complexes
limb body wall complex
OEIS complex
omphalocele-radial ray (ORR) complex
Pentalogy of Cantrell
amniotic ...
Article
Fetal ascites
Fetal ascites refers to the accumulation of free fluid in the fetal abdomen. It is often considered under the same spectrum of hydrops fetalis.
Pathology
Etiology
any condition that results in hydrops fetalis
additional causes include
idiopathic
bowel perforation (e.g. meconium peritonitis...
Article
Fetal bowel dilatation
Fetal bowel dilatation can occur from many causes, which include:
intestinal atresias: mainly distal
anal atresia
apple-peel intestinal atresia
ileal atresia
jejunal atresia
jejuno-ileal atresia
Hirschsprung disease
megacystis microcolon hyperperistalsis syndrome 4
congenital chloride d...
Article
Fetal brain tumors
Fetal brain tumors are uncommon and tends to have very different pathological spectrum than that observed in adults; in order of decreasing frequency:
fetal intracranial teratoma: most common tumor by far
astrocytoma/glioblastoma: next most common
craniopharyngioma: papillary type
primitive ...
Article
Fetal cardiac tumors
Fetal cardiac tumors refer to primary cardiac tumors that can present in the in utero population.
Epidemiology
Fetal cardiac tumors are rare; the prevalence, reported from autopsy studies of patients of all ages, varies from 0.0017-0.28 % 2.
Pathology
Known cardiac tumor types that present ...
Article
Fetal chylothorax
Fetal chylothorax is defined as the presence of lymphatic fluid within the pleural cavity of the fetus.
Pathology
Associations
pulmonary hypoplasia
hydrops fetalis
premature delivery
Radiographic features
Antenatal ultrasound
may show echogenic fluid in the pleural cavities
Treatment
S...
Article
Fetal clenched hands
Fetal clenched hands are an antenatal ultrasound observation where the fetal hands are in a constant (permanently) clenched position as if being unable to extend.
Pathology
Some authors 3 suggest that the abnormal posture results in part from:
muscle variations along the radial margin of the...
Article
Fetal death in utero
Fetal death in utero (FDIU), also known as intrauterine death (IUD), is the term used when the death of a fetus occurs after the 20th week of pregnancy. Prior to this, it is considered a miscarriage.
Terminology
IUD is often also used as an abbreviation for an intrauterine contraceptive device...
Article
Fetal intra-abdominal cysts (differential)
Fetal intra-abdominal cystic lesions can arise from a number of physiological and pathological causes.
Physiological
fetal gastric dilatation / fetal gastric bubble (can be pathological if there is a gastric outlet obstruction
normal fetal gallbladder
Pathological
No color flow
fetal chole...
Article
Fetal intracranial calcification
Fetal intracranial calcification refers to intracranial calcification detected in utero. This can arise from a number of pathologies which include:
in utero infections
fetal toxoplasmosis infection: calcification tends to be randomly distributed
fetal cytomegalovirus infection1: calcificatio...
Article
Fetal intracranial cystic lesions
Fetal intracranial cystic lesions can arise from a number of pathologies, including:
Non-tumourous
fetal arachnoid cyst
fetal choroid plexus cyst
fetal connatal cyst
fetal porencephalic cyst
fetal interhemispheric cyst
fetal subependymal cyst
dorsal cyst of holoprosencephaly
Blake pouc...
Article
Fetal intracranial hemorrhage
Fetal intracranial hemorrhage may occur either within the cerebral ventricles, subdural space or infratentorial fossa.
Pathology
Hemorrhages can occur in a number of situations:
mechanical trauma, e.g. maternal abdominal blunt or birth trauma
severe fetal hypoxia
background fetal thrombocyt...
Article
Fetal intrahepatic calcification
Fetal intrahepatic calcification can be a relatively common finding. Calcifications in the liver can be single or multiple and in most cases in which isolated hepatic calcific deposits are detected, there is usually no underlying abnormality.
The presence of isolated intrahepatic calcification ...
Article
Fetal limb bowing
Fetal limb bowing may be a feature of skeletal dysplasia, particularly if it is severe. A mild degree of lateral bowing of the femur can occur as part of normal variation.
Conditions associated with fetal limb bowing include:
campomelic dysplasia 1
thanatophoric dysplasia 2: particularly type...
Article
Fetal pleural effusion
Fetal pleural effusions (FPE) refer to an accumulation of pleural fluid in utero. It can refer to either a fetal chylothorax or a fetal hydrothorax.
Pathology
A fetal pleural effusion can occur as part of hydrops fetalis, in association with other anomalies without hydrops or in isolation - pr...
Article
Fetal rib fractures
Fetal rib fractures can be caused by certain skeletal dysplasias. These include:
osteogenesis imperfecta: type II - one of the classical causes of fetal rib fractures
achondrogenesis: type Ia - Houston-Harris sub type
Article
Fetal tumors
Although rare, a number of tumors may be diagnosed antenatally. These fetal tumors are a diverse and a unique group of conditions, and include:
neuroblastoma: most common tumor overall
teratomas
sacrococcygeal teratoma
head and neck teratoma/epignathus
mediastinal teratoma
intrapericardial...
Article
Fetal ventriculomegaly (differential)
Fetal ventriculomegaly (ventricle width >10 mm) is an important finding in itself and it is also associated with other central nervous system abnormalities. For more information, see the main article fetal ventriculomegaly.
Differential diagnosis
Fetal ventriculomegaly can be thought of in ter...
Article
Fibropolycystic liver disease
Fibropolycystic liver disease is a collective term for a group of congenital liver and biliary abnormalities resulting from abnormal development of the ductal plates. Disease in this group include:
congenital hepatic fibrosis
biliary hamartomas
autosomal dominant polycystic disease
Caroli d...
Article
Fibrous lesions
The differential for fibrous lesions is wide and includes:
non-ossifying fibroma
fibrous dysplasia
osteofibrous dysplasia / adamantinoma
desmoplastic fibroma
fibromatoses, e.g.
plantar fibromatosis
palmar fibromatosis
malignant fibrous histiocytoma / fibrosarcoma
dermatofibrosarcoma p...
Article
Floating meniscus
Floating meniscus (also known as meniscal avulsion) occurs in acute traumatic settings when the meniscotibial coronary ligaments get disrupted leading to avulsion of the meniscus from the tibial plateau.
Radiographic features
MRI
Displacement of the meniscus for 5 mm or more from the tibial p...
Article
Flowing ossifications
Flowing ossifications are seen in diffuse idiopathic skeletal hyperostosis (DISH).They are defined as heterotopic ossifications involving the anterior longitudinal ligament, paraspinal connective tissues and annulus fibrosus of at least four contiguous vertebral bodies and are originally describ...
Article
Fluid-fluid level containing bone lesions
Fluid-fluid level containing bone lesions are best seen on MRI, although with narrow window width they can also be appreciated on CT.
Epidemiology
Their prevalence is estimated at ~3% of bone and soft tissue tumors 1.
Differential diagnosis
Their presence is non-specific, as they are seen in...
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
Focal gallbladder wall thickening (differential)
Focal gallbladder wall thickening is an imaging finding that includes both benign and malignant etiologies.
cholecystoses
cholesterolosis
adenomyomatosis
masses
gallbladder polyps
gallbladder carcinoma: look for infiltration into adjacent organs, metastases, lymphadenopathy, bile duct dil...
Article
Focal gas collection in right upper quadrant (differential)
Focal gas collection in right upper quadrant on plain radiographs can occur from a number of pathologies. Things to consider are:
enterobiliary fistula: common types include cholecystoduodenal fistula and cholecystocolic fistula. It may occur with:
gallstone ileus (being most common) 3
perfor...
Article
Focal hypodense hepatic lesions on non-enhanced CT (differential)
Focal hypodense hepatic lesions on a non-contrast CT scan can result from a number of pathological entities, including:
neoplasms
benign
hepatic hemangioma
adenoma
biliary hamartoma: von Meyenberg complexes 2
malignant
hepatoma/hepatocellular carcinoma (HCC)
hepatic lymphoma
hepatic ha...
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
Gamut
Gamuts in radiology refer to the complete list of differential diagnoses for any radiological finding. We include gamut as a section for articles on Radiopaedia.org.
History and etymology
According to Maurice Reeder, writing in the preface of his own eponymous text on gamuts, it was the trailb...
Article
Gas in the urinary bladder
There are numerous causes of gas in the urinary bladder. In the hospital setting by far the most common is the recent placement of an indwelling urinary catheter. Other causes include 1:
iatrogenic
indwelling urinary catheter is by far the most common cause
cystoscopy, etc.
emphysematous cys...
Article
Gasless abdomen
A gasless abdomen refers to a paucity of gas on abdominal radiography, and the specific cause can usually be identified when the patient's history is known. Common causes include:
small bowel obstruction
bowel ischemia
congenital atresia
ascites
pancreatitis
gastroenteritis
large abdomina...
Article
Gastric outlet obstruction
Gastric outlet obstruction is a syndrome resulting from mechanical obstruction of stomach emptying.
Pathology
Etiology
Gastric outlet obstruction can be due to malignant or benign causes.
Malignant
adenocarcinoma (second most common 4)
GIST
lymphoma (less common than other malignancies as...
Article
Generalized increased bone density in adults
The causes of generalized increase in bone density in adult patients, also known as generalized or diffuse osteosclerosis, can be divided according to broad categories:
hematological disorders
myelosclerosis
marrow cavity is narrowed by endosteal new bone
patchy lucencies due to the persist...
Article
Generalized increased bone density in children
The causes of generalized increased bone density in pediatric patients can be divided according to a broad category of causes:
skeletal dysplasias
osteopetrosis
pyknodysostosis
metabolic
renal osteodystrophy
poisoning
lead
dense metaphyseal bands
cortex and flat bones may also be slight...
Article
Generalized increase in hepatic echogenicity
Causes of generalized increase in hepatic echogenicity include:
diffuse fatty change
cirrhosis: and/or coarsening
chronic hepatitis 3: and/or coarsening
diffuse infiltration or deposition
malignant process
granulomata
tuberculosis
brucellosis
sarcoidosis
glycogen storage disease
hemo...
Article
Generalized osteopenia
Generalized osteopenia refers to osteopenia diffusely affecting the bones.
Differential diagnosis
The differential diagnosis is wide and includes:
osteoporosis: decreased osteoid production
osteomalacia: undermineralisation of osteoid
hyperparathyroidism
multiple myeloma
diffuse metastase...
Article
Generalized periosteal reaction
The list of causes of a generalized periosteal reaction overlaps that of symmetrical periosteal reaction, and includes 1,2:
vascular stasis (common)
congenital syphilis
fluorosis
Gaucher disease
hypertrophic osteoarthropathy
pachydermoperiostosis
hypervitaminosis A
infantile cortical hyp...
Article
Generalized reduced hepatic echogenicity
Causes of generalized reduction of liver echogenicity on ultrasound include:
acute hepatitis
diffuse malignant infiltration
See also
generalized increase in liver echogenicity
hepatic attenuation on CT
Article
Giant cell carcinoma of the lung
Giant cell carcinomas of the lung are a rare type of non-small cell lung carcinomas (NSCLC) classified under sarcomatoid carcinomas of the lungs.
Epidemiology
They represent less than 0.5% of all NSCLC 2. There is a recognized association with smoking 1.
Clinical presentation
Symptoms are n...