Medical devices in the thorax are regularly observed by radiologists when reviewing radiographs and CT scans.
tubing, clamps, syringes, scissors, lying on or under the patient
rubber sheets, foam mattresses, clothing, hair braids, nipple piercings, etc., may also b...
Dilated ducts on breast imaging may be seen on many breast imaging modalities and can arise from a number of causes which can be both benign or malignant.
physiological lactational changes
mammary duct ectasia
breast neoplasm 2-3
Certain well-defined breast cancers tend to lack the characteristic spiculation and can give false reassurance of more benign entities on both ultrasound and mammography. These include:
certain high grade invasive ductal carcinomas: not enough time for a desmoplastic reaction to form spiculatio...
There are a number of lesions that appear hyperechoic on ultrasound. Such lesions can be either completely or partly hyperechoic and include both benign and malignant entities.
fat containing breast lesions
lipoma of the breast
fibroadenolipoma (hamartoma) of the breast
A cystic breast mass is a mass that contains both solid and fluid components. This can occur from both benign and malignant causes.
complex breast hematoma
complex breast abscess
breast cyst with associated inflammation and hemorrhage
fibrocystic changes and oil cysts 2...
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
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...
Calcific axillary lymphadenopathy is in general, more concerning than axillary lymphadenopathy alone and is particularly so if it contains microcalcifications. While this is concerning for malignancy, it can also occur from occasional nonmalignant causes.
Unilateral axillary lymphadenopathy while being more concerning than bilateral axillary lymphadenopathy can still arise from a variety of benign, as well as malignant, causes.
other regional infective causes
ipsilateral arm infection, e.g. cellulitis
The presence of skin thickening on mammography is variably defined, usually being more than 2 mm in thickness. It can result from a number of both benign and malignant causes. They include:
inflammatory breast cancer: one of the most concerning causes of skin thickening: this usually...
Asymmetries in mammography represent a spectrum of morphological descriptors for a unilateral fibroglandular-density finding seen on one or more mammographic projections that do not meet criteria for a mass. The term refers to a density finding and should not be confused with asymmetry in breast...
The term high-risk breast lesion is given to a breast lesion that carries an increased risk for the future development of breast cancer or carries suspicion of a more sinister pathology around or in association with the lesion. The term has some overlap with borderline breast disease. Many radio...
Coarse macrocalcifications within the breast are a morphological descriptive term for a type of breast calcification.
involuting fibroadenomas (classic popcorn calcification)
chronic renal disease with hypercalcemia 1
rarely seen in malignancy 2
invasive breast c...
Milk of calcium within a breast cyst is a mammographic feature observed when there is dependent calcium layering within breast cysts. It is typically observed as "tea cup" or "crescent shaped" calcifications on a true lateral (LM or ML) view or occasionally on a MLO view. On a CC view, these cal...
Bone-forming tumors are a subset of bone tumors that are characterized by their propensity to form excess osteoid. They can be further subdivided into benign and malignant tumors.
ossifying fibroma 1
Demyelinating disorders are a subgroup of white matter disorders characterized by the destruction or damage of normally myelinated structures. These disorders may be inflammatory, infective, ischemic or toxic in origin and include 1-7:
multiple sclerosis (MS)
Hypomyelinating disorders are a heterogeneous subset of white matter disorders characterized by abnormally low amounts of myelination.
In distinction to other myelin disorders, hypomyelination is a permanent deficiency in myelin deposition rather than myelin destruction (i.e. demyelination) or ...
Amorphous calcifications, previously known as indistinct calcifications, are a morphological descriptor for breast calcifications that are small and/or hazy such that no clearly defined shape/form can be ascribed.
Many benign and malignant conditions may be seen in association with ...
Transalar (transsphenoidal) herniation describes herniation of brain matter in and around the middle cranial fossa across the greater sphenoid wing and can be ascending or descending. Compression of structures against the sphenoid bone results in symptoms.
Transalar herniation is not...
Fetal cardiac tumors refer to primary cardiac tumors that can present in the in utero population.
Fetal cardiac tumors are rare; the prevalence, reported from autopsy studies of patients of all ages, varies from 0.0017-0.28 % 2.
Known cardiac tumor types that present ...
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.
This feature can be seen in many conditions (in alphabetical order):
Non-visualization of the fetal stomach on ultrasound can occur with various physiological as well as pathological processes. It becomes a significant sonographic observation >14 weeks of gestation (about the time the fetus begins to swallow).
physiological emptying: transient
Fetal intracranial hemorrhage may occur either within the cerebral ventricles, subdural space or infratentorial fossa.
Hemorrhages can occur in a number of situations:
mechanical trauma, e.g. maternal abdominal blunt or birth trauma
severe fetal hypoxia
background fetal thrombocyt...
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
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...
Pneumatoceles are intrapulmonary gas-filled cystic spaces that can have a variety of sizes and appearances. They may contain gas-fluid levels and are usually the result of ventilator-induced lung injury in neonates or post-infectious. They should not be mistaken for a cavitating lung mass.
Pulmonary blebs are small subpleural thin-walled air-containing spaces, not larger than 1 or 2 cm in diameter (with the precise limit varying by source). Their walls are less than 1 mm thick. If they rupture, they allow air to escape into the pleural space resulting in a spontaneous pneumothorax...
Uterine enlargement can occur in a number of situations from both diffuse and focal processes. These include:
gestation related events
normal intrauterine pregnancy
molar pregnancy - gestational trophoblastic disease
postpartum uterus - still larger than usual
Right lower lobe (RLL) collapse has distinctive features, and is usually relatively easily identified. The smaller overlying heart shadow obscures less lung compared with left lower lobe collapse.
Findings of lower lobe collapse can be grouped together as they are almost identical on both side...
Right upper lobe collapse has distinctive features, and is usually easily identified on frontal chest radiographs; much more so than left upper lobe collapse.
For a general discussion please refer to the article on lobar collapse.
Collapse of the right ...
Right middle lobe collapse (or simply termed middle lobe collapse) has distinctive features, but can be subtle on frontal chest radiographs.
For a general discussion please refer to the article on lobar collapse.
It is important to note that of all the lobes, the right middle lobe is the mo...
The term grouped calcifications is used in mammography when relatively few breast microcalcifications reside within a small area. There must be at least five calcifications present within 1 cm of each other 3. At the most, it may refer to a larger number of calcifications present within 2 cm of ...
A multicentric breast cancer is a term given to a breast cancer where there are two or more breast cancers separated by normal breast tissue (often taken as 5 cm of separation 4). It is related to but distinct from the term multifocal breast cancer.
At a pathological level It can also mean 2
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)
anterior mediastinal mass
prominent epicardial fat pad
AP projection (e.g supine radiographs taken w...
Papillary lesions of the breast comprise a wide group and range from benign to malignant.
They develop as tufts of epithelium with a ﬁbrovascular core that arborizes into branching papillae and protrude into the duct lumen.
papilloma of breast / intraductal papilloma of the ...
A small placenta if observed on antenatal ultrasound can arise from a number of situations. They include:
variation in placental morphology: where only part of the placenta is seen
bilobed placenta: with only one lobe seen
succenturiate lobe: with either main lobe or succenturiate lobe not se...
Multifocal breast cancer refers to two or more individual breast cancers diagnosed at the same time within the same quadrant of the same breast 1.
Soft tissue calcification is commonly seen and caused by a wide range of pathology.
There is a wide range of causes of soft tissue calcification 1:
dystrophic soft tissue calcification (most common)
chronic venous insufficiency 2
Fetal bowel dilatation can occur from many causes, which include:
intestinal atresias: mainly distal
apple-peel intestinal atresia
megacystis microcolon hyperperistalsis syndrome 4
congenital chloride d...
Asymmetry in breast size can arise from a number of factors.
Breasts are rarely absolutely the same size or volume. Normal variation is common. Most females have slight discrepancies in breast size. Asymmetric progressive breast enlargement is unusual but known. The role of the breas...
Abnormally thickened endometrium on imaging may occur for a number of reasons which may be categorized based on whether or not they are related to pregnancy. Etiologies may also be classified based on whether the patient is premenopausal or postmenopausal.
The differential diagnosis for a vertebral body mass is broad and may range from a completely benign bone island to a malignant primary bone tumor.
Broadly, these lesions can be separated into:
primary bone tumors
secondary metastatic disease
Fetal intracranial cystic lesions can arise from a number of pathologies, including:
fetal arachnoid cyst
fetal choroid plexus cyst
fetal connatal cyst
fetal porencephalic cyst
fetal interhemispheric cyst
fetal subependymal cyst
dorsal cyst of holoprosencephaly
Lethal skeletal dysplasias form a heterogeneous group that is commonly characterized as being non-survivable for prolonged periods ex-utero. They include (in alphabetical order):
chondrodysplasia punctata: lethal variants
Carotid pacemakers, also known as implantable carotid sinus stimulators, are devices that deliver activation energy, via carotid leads, to the carotid baroreceptors. This is sometimes offered for drug-resistant hypertension. The baroreceptors send signals to the brain and the signals are interpr...
Congenital renal anomalies comprise of vast spectrum of pathologies and include:
congenital renal hypoplasia
congenital cystic renal disease
infantile polycystic renal disease: autosomal recessive polycystic ki...
Mammographic screening detects early breast cancers and thereby reduces potential mortality. However, its sensitivity is inversely related to breast density 1.
Altered density between two mammograms can arise in a number of situations:
Affecting both breasts:
interval commencement/cessation ...
Fetal intra-abdominal cystic lesions can arise from a number of physiological and pathological causes.
fetal gastric dilatation / fetal gastric bubble (can be pathological if there is a gastric outlet obstruction
normal fetal gallbladder
No color flow
The (absent) pedicle sign, also called the winking owl sign, occurs on plain radiograph of the spine when a pedicle is absent 5.
The term, winking owl sign, where the missing pedicle corresponds to the closed eye, the contralateral pedicle to the other round open eye, and the spinous process to...
A narrow fetal thorax on antenatal ultrasound can be present with a number of anomalies which include:
Jeune syndrome - asphyxiating thoracic dysplasia
short rib polydactyly syndro...
Calcified pulmonary nodules are a subset of hyperdense pulmonary nodules and a group of nodules with a relatively narrow differential.
The most common cause of nodule calcification is granuloma formation, usually in the response to healed infection.
A pulmonary mass is any area of pulmonary opacification that measures more than 30 mm, an arbitrary but useful measurement. The commonest cause of a pulmonary mass is primary lung cancer 1-3:
granuloma: most common non-malignant cause
Interstitial lung disease (ILD) is an umbrella term that encompasses a large number of disorders that are characterized by diffuse cellular infiltrates in a periacinar location. The spectrum of conditions included is broad, ranging from occasional self-limited inflammatory processes to severe de...
There are relatively few causes of low signal intensity renal parenchyma. Causes include:
paroxysmal nocturnal hemoglobinuria
mechanical: malfunctioning prosthetic cardiac valve
sickle cell disease
hemorrhagic fever with renal syndrome (HFRS)
The differential diagnosis of a cystic mass adjacent to the angle of mandible includes:
2nd branchial cleft cyst
lymphatic malformation (lymphangioma)
from metastatic squamous cell carcinoma
from metastatic papillary thyroid cancer
Breast calcifications are deposits of calcium salts in the breast, which are radio-opaque on mammography. The majority are benign, but they can be associated with cancer. The ability to diagnose and appropriately manage the significant microcalcifications and differentiate them from innocuous fi...
Fetal anterior abdominal wall defects can occur with a number of pathologies.
limb body wall complex
omphalocele-radial ray (ORR) complex
Pentalogy of Cantrell
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)
congenital tracheal stenosis
Spinal cord compression (SCC) is a surgical emergency, usually requiring prompt surgical decompression to prevent permanent neurological impairment. If the spinal roots below the conus medullaris are involved, and there are characteristic symptoms and signs, it is termed cauda equina syndrome.
A shortened fetal humerus is a morphological description and is usually defined when the humeral length falls below the 5th percentile or less than 0.9 as predicted by the biparietal diameter (BPD). It can occur in isolation or in association with a number of other anomalies.
The humeral length...
Spinal metastasis is a vague term which can be variably taken to refer to metastatic disease to any of the following:
vertebral metastases (94%)
may have epidural extension
intradural extramedullary metastases (5%)
intramedullary metastases (1%)
Each of these are discussed separately. Below...
Syndactyly (plural: syndactylies) refers to a congenital fusion of two or more digits. It may be confined to soft tissue (soft tissue syndactyly / simple syndactyly) or may involve bone (bony syndactyly / complex syndactyly).
The overall estimated incidence is at ~1 per 2500 to 50...
Cutaneous calcifications in breast imaging can form in dermal sweat glands after low grade folliculitis and inspissation of sebaceous material. Calcifications may also form in moles and other skin lesions. The vast majority of calcifications are coincidental findings on mammography.
Placentomegaly is a term applied to an abnormally-enlarged placenta.
It can be associated with a number of maternal and fetal disorders which include:
chronic intrauterine infections
A coup-contrecoup injury is a term applied to head injuries and most often cerebral contusions and traumatic subarachnoid hemorrhage. It refers to the common pattern of injury whereby damage is located both at the site of impact (often less marked) and on the opposite side of the head to the poi...
A shortened fetal femur is a morphological descriptor and is usually defined when the femoral length falls below the 5th centile for gestational age (some define it when it is under the 2.5th centile 5) or less than 0.91 predicted by the biparietal diameter (BPD). It can occur in isolated or in ...
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.
A fetal pleural effusion can occur as part of hydrops fetalis, in association with other anomalies without hydrops or in isolation - pr...
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 ...
There are a wide range of causes for subarachnoid FLAIR hyperintensity, both pathological and artifactual.
FLAIR vascular hyperintensities in acute stroke 1,4,8
Fetal ascites refers to the accumulation of free fluid in the fetal abdomen. It is often considered under the same spectrum of hydrops fetalis.
any condition that results in hydrops fetalis
additional causes include
bowel perforation (e.g. meconium peritonitis...
Fat containing breast lesions generally have some radiolucent component on mammography.
They are generally classified at BIRADS II lesions.
fat necrosis within the breast/oil cyst
intramammary lymph node: classically has a cen...
Per vaginal (PV) bleeding during pregnancy is a common clinical presentation that often necessitates obstetric ultrasound for the assessment of the hemorrhage, and of fetal well being.
The potential causes vary with the stage of gestation.
Bleeding in the first trimester
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...
Umbilical cord cysts can refer to any cystic lesion associated with the umbilical cord. They can be single (more common) or multiple.
They may be seen in ~3% of pregnancies in the first trimester 8.
There are associations (especially when there are additional sonogr...
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.
Several syndromic conditions are associated with this observation including:
Cystic retroperitoneal lesions carry a relatively broad differential, which includes:
retroperitoneal lymphatic malformation
retroperitoneal mucinous cystadenoma
retroperitoneal cystic teratoma
retroperitoenal cystic mesothelioma
pseudomyxoma retroperitonei with cystic change
The World Health Organization (WHO) classification of tumors of the uterine corpus is a commonly used classification system for uterine tumors. It is part of the 5th edition WHO classification of female genital tumors, published in 2020 1.
Endometrial epithelial tumors and prec...
Basal ganglia and thalamus signal abnormalities occur in a wide variety of conditions. Ischemia/hypoxia, metabolic disorders and toxins, particularly those that affect the respiratory chain, have a predilection for affecting the basal ganglia as they are highly metabolically active.
They can b...
Patella alta, or a high-riding patella, describes a situation where the position of the patella is considered high. It may be idiopathic or may result secondary to a patellar tendon rupture.
Several conditions are known to be associated with patella alta, including:...
Lesions of both middle cerebellar peduncles is uncommon, but has a relatively long list of differential diagnoses, including 1,2:
multiple systemic atrophy (MSA)
fragile X-associated tremor/...
Differential diagnosis for calcified masses in the mandible includes:
calcifying odontogenic cyst (Gorlin cyst)
calcifying epithelial odontogenic tumor (Pindborg tumor)
Right atrial (RA) enlargement is less common, and harder to delineate on chest radiograph, than left atrial (LA) enlargement.
Enlargement of the right atrium (RA) can result from a number of conditions, including:
raised right ventricular pressures
pulmonary arterial hype...
A cavernous sinus mass has a wide differential, including:
orbital apical inflammation with cavernous sinus involvement (Tolosa-Hunt syndrome)
any of the cranial nerves traversing the cavernous sinus: III, IV, V (V1 and V2) and VI
trigeminal schwannoma is...
Common causes of polyostotic bone lesions in adults include:
arthritic or synovial-based lesions
non-ossifying fibromas (fibroxanthomas)
polyostotic fibrous dysplasia (McCune-Albright syndrome)
An obstructive uropathy is a catch-all term encompassing any cause of complete or partial, congenital or acquired, and permanent or intermittent obstruction of the urinary tract. Depending on the severity of obstruction and extent, it may result in permanent change in both the collecting system ...
Coronal vertebral clefts refer to the presence of radiolucent vertical defects on a lateral radiograph.
It is most often seen in premature male infants 1,3. As they can occur as part of normal variation (especially in the lower thoracic-upper lumbar spine of premature infants) t...
A diffuse homogeneous bone marrow FDG uptake usually reflects hyperplastic bone marrow which can be seen in the following conditions:
granulocyte colony-stimulating factor (G-CSF)
Periportal hyperechogenicity can result from many causes including:
schistosomiasis of the portal region
recurrent pyogenic cholangitis (oriental)
inflammatory bowel disease: has been described to give "echo-rich" periportal cuffing 2
Periportal hypoechogenicity can result from many causes:
orthotopic liver transplant rejection
malignant lymphatic obstruction
Breast density refers to the amount of fibroglandular tissue in a breast relative to fat. It can significantly vary between individuals and within individuals over a lifetime.
There are four descriptors for breast density on mammography in the 5th edition of BI-RADS 1,2:
Retained gallstones, also called dropped or slipped gallstones, are common during a laparoscopic cholecystectomy, with a reported incidence of 0.1–20%, and occur when gallstones are inadvertently spilled into the peritoneal cavity.
Many cases of dropped gallstones will be...
Cardiomegaly is a catch-all term to refer to enlargement of the heart, and should not be confused with causes of enlargement of the cardiomediastinal outline, or enlargement of the cardiac silhouette.
There are many etiologies for cardiomegaly:
congestive heart failure...
Intracranial cystic lesions in the perinatal period can carry a relatively wide differential which includes:
Supratentorial cystic lesions
choroid plexus cyst