Chronic interstitial pneumonitis is a broad descriptive term where an interstitial pneumonia has a prolonged course. It can arise of a range of etiologies. The term does not usually imply a specific radiographic pattern and includes UIP, NSIP or other pattern. As a general rule there is little o...
Chronic primary adrenal insufficiency has a number of causes. Primary adrenal insufficiency is termed Addison disease.
idiopathic atrophy: autoimmune adrenalitis 1
tuberculosis 1: 25% calcify
fungal disease 1
Chronic suppurative lung disease (CSLD) refers to a group of conditions which includes:
primary ciliary dyskinesia
This term is usually used in the context of pediatric patients.
Chronic unilateral airspace opacification is a subset of the differential diagnoses for airspace opacification. An exhaustive list of all possible causes of chronic unilateral airspace opacities is long, but a useful framework is as follows:
Cicatrisation atelectasis is a form of lung atelectasis which occurs as a result of scarring or fibrosis that reduces lung expansion. Cicatrisation atelectasis is classic in tuberculosis. The term is closely related to cicatrisation collapse when an entire lobe is collapsed from the same process...
There are several pulmonary complications that can arise in the setting of cirrhosis:
hepatopulmonary syndrome (HPS): considered the commonest
portopulmonary hypertension (POPH)
hepatic hydrothorax (HH)
intrathoracic portosystemic collateral vessel formation
The development of portal hypert...
Clavicle tumors may be malignant or benign.
osteoma: uncommon, sclerotic, hamartomatous surface lesion
enchondroma: rare, geographic, intramedu...
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...
Coal mine dust lung disease encompasses a number of occupational lung diseases 1,2:
coal workers' pneumoconiosis (CWP)
mixed dust pneumoconiosis
dust-related diffuse fibrosis
chronic obstructive pulmonary disease (COPD)
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...
Coarsened hepatic echotexture is a sonographic descriptor used when the uniform smooth hepatic echotexture of the liver is lost. This can occur due to a number of reasons which include:
conditions that cause hepatic fibrosis 1
various types of hepatitis 3
A Codman triangle is a type of periosteal reaction seen with aggressive bone lesions. The periosteum does not have time to ossify with shells of new bone (e.g. as seen in a single layer and multilayered periosteal reaction) in aggressive lesions, so only the edge of the raised periosteum will os...
A coin lesion refers to a round or oval, well-circumscribed solitary pulmonary lesion. It is usually 1-5 cm in diameter and calcification may or may not be present 1,3. Typically but not always the patient is asymptomatic 1.
The differential diagnosis for such lesions i...
Colonic strictures can be long (>10 cm) or short.
scirrhous colorectal carcinoma (apple core sign)
post surgical (anastamotic stricture)
scirrhous colorectal carcinoma
inflammatory bowel disease
Colpocephaly is a descriptive term for a disproportionate prominence of the occipital horns of the lateral ventricles. It can result from a wide range of congenital insults.
Patients may present with motor abnormalities, cognitive deficit, visual abnormalities, and seizur...
Communicating hydrocephalus is a type of hydrocephalus where CSF is able to leave the ventricular system.
Communicating hydrocephalus is commonly used as the opposite of obstructive hydrocephalus which leads to much unnecessary confusion, as most causes of communicating hydrocepha...
There are many complications that can occur following gastric banding. It is helpful to divide these into early and late post-surgical complications.
Although the exact mode of presentation can vary depending on the underlying complication common modes of presentation tha...
Complications of cranial radiation therapy are fairly common, particularly in long-term survivors, and especially in pediatric patients.
Cranial radiotherapy is used for a variety of brain tumors, either in isolation or in combination with concurrent chemotherapy. Complications from irradiation...
Complications of total hip arthroplasty are common and it is essential for the radiologist to be aware of them in the assessment of radiographs of total hip replacements. Complications are many and can occur at various time intervals following the initial surgery:
aseptic loosening: considered ...
Compressive atelectasis refers to a form of lung atelectasis due to compression by a space-occupying process.
Some authors describe it as a subtype of passive (relaxation) atelectasis where the reduction in lung volume is greater than its normal relaxed state 1. Whereas others describe it as th...
There are many conditions that can involve both skin and bone.
osteolytic bone lesions
basal cell nevus syndrome
langerhans cell histiocytosis
Congenital anomalies of the male urethra include various anomalies due to complex development of urethra. These anomalies can be isolated or in association with other coexisting anomalies. They can be categorized as following:
urethral agenesis (or atresia)
Congenital calvarial defects are a group of disorders characterized by congenital calvarial bone defects that vary in severity.
CT with 3D shaded surface reformats is the best imaging tool as it demonstrates calvarial defects and bone margins:
Congenital limb amputation is the absence of a fetal limb or part of a limb that usually occurs due to disruption of vascular supply.
Congenital amputations occur in 0.5 (range 0.03-1) per 1000 live births 2.
They are slightly more common in the upper limb (60%) than ...
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 kidney disease (ARPKD):...
Congenital ventriculomegaly can have a large number of syndromic associations.
fetal alcohol syndrome
Congestive hepatopathy includes a spectrum of hepatic derangements that can occur in the setting of right-sided heart failure (and its underlying causes). If there is subsequent hepatic fibrosis the term cardiac cirrhosis may be used. The condition can rarely occur as a result of non-cardiac cau...
Convexal subarachnoid hemorrhages (cSAH) are non-traumatic intracranial hemorrhages that occur within the surface sulci of the brain (cf. basal cisternal distribution of aneurysmal SAH).
There are various causes of convexal subarachnoid hemorrhage, some of which include:
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...
Renal cortical nephrocalcinosis is ~20 times less common than medullary nephrocalcinosis.
renal cortical necrosis: common 2
toxemia of pregnancy
extracorporeal shock wave lithotripsy (ESWL)
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...
Craniovertebral junction (CVJ) anomalies can be congenital, developmental or due to malformation secondary to any acquired disease process. These anomalies can lead to cranial nerve compression, vertebral artery compression, and obstructive hydrocephalus.
The craniovertebral junction...
Crazy paving refers to the appearance of ground-glass opacity with superimposed interlobular septal thickening and intralobular septal thickening, seen on chest HRCT. It is a non-specific finding that can be seen in a number of conditions.
Only a small number of pulmonary diseases are known to directly cross the lung fissures such that the lung pathology extends from one lobe via the interlobar fissure into an adjacent lobe 1. The finding is most commonly due to primary malignancy, however, some infections are also known to do so....
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.
A number of entities can present as cyanotic congenital heart disease. These can be divided into those with increased (pulmonary plethora) or decreased pulmonary vascularity :
increased pulmonary vascularity
total anomalous pulmonary venous return (TAPVR) (types I and II)
transposition of the...
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...
The musculoskeletal manifestations of cystic fibrosis are uncommon compared to the well known respiratory manifestations.
For general discussion of cystic fibrosis, and a discussion of its other manifestations, please refer to:
cystic fibrosis (parent article)
pulmonary manifestations of cys...
Cystic hepatic metastases are included in the differential for new cystic liver lesions. The internal cystic component may represent necrosis as the tumor outgrows its hepatic blood supply, or it may represent a mucinous component, similar to the primary tumor.
The liver and lungs are the most ...
There several cystic lesions around the vagina and female urethra; some of the imaging differential considerations would include:
Gartner duct cyst: at or above the level of the pubic symphysis anterior to the vaginal wall
Bartholin gland cyst: posterolateral to distal v...
Cystic lesions of the liver carry a broad differential diagnosis:
simple hepatic cyst
adult polycystic liver disease
ciliated hepatic foregut duplication cyst 6
infectious: inflammatory conditions
pyogenic hepatic abscess
The differential for cystic lesions of the pancreas includes:
intraductal papillary mucinous neoplasm (IPMN)
serous cystadenoma uncommonly uni/macrolocular
simple pancreatic cyst
pancreatic cysts occur in association with
von Hippel Lindau syndrome
Testicular cystic lesions are a relatively common occurrence on testicular ultrasound. They result from widely variable pathological entities ranging from benign to malignant. These entities include:
simple testicular cyst
tunica albuginea cyst (mesothelial cyst)
cystic transformation of rete...
Cystic lung disease is an umbrella term used to group the conditions coursing with multiple lung cysts.
The clinical presentation is an important clue to the differential diagnosis of cystic lung diseases 12.
Diseases that present with insidious dyspnea or spontaneous p...
Cystic lesions in pediatric patients are usually congenital lesions and, as such, can be seen antenatally and following delivery.
These congenital lesions are predominantly covered by the overarching diagnosis of bronchopulmonary foregut malformation. This is a ...
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
The differential diagnosis for cystic masses of the mediastinum include:
esophageal duplication cyst
cystic teratoma of mediastinum
cystic degeneration of an intrathoracic tumor
Cystic or necrotic appearing lymph nodes can be caused by a number of infectious, inflammatory or malignant conditions:
squamous cell carcinoma metastases
plasmacytoid T-cell leukemia
acute myeloid leukemia
herpes simplex lymphadenit...
The differential for cystic parotid lesions includes:
bilateral cystic parotid lesions
benign lymphoepithelial lesions of HIV
unilateral cystic parotid lesion(s)
first branchial cleft cyst
Cystic pulmonary metastases are atypical morphological form on pulmonary metastases where lesions manifest as distinct cystic lesions. It is slightly different from the term cavitating pulmonary metastases in that the lesions are extremely thin walled.
It has been reported with many ...
Cystic retroperitoneal lesions can carry a relatively broad differential, which includes:
retroperitoneal lymphatic malformation
retroperitoneal mucinous cystadenoma
retroperitoneal cystic teratoma
retroperitoenal cystic mesothelioma
pseudomyxoma retroperitonei with cystic change
A cystic spinal lesion can result from a number of disease entities. They include:
Dandy walker malformation
certain skeletal dysplasias 2
tricho-rhino-phalangeal syndrome type I
ependymal cysts 4
There is broad differential for cyst-like lesions around the knee.
popliteal synovial cyst - Baker cyst
intra-articular ganglion cyst
ACL ganglion cyst
PCL ganglion cyst
Hoffa fat pad ganglion cyst
extra-articular ganglion cyst
Cytotoxic lesions of the corpus callosum (CLOCCs) represent a collection of disparate conditions that can cause signal change in the corpus callosum, usually involving the splenium.
The term cytotoxic lesions of the corpus callosum (CLOCCs) has been proposed recently 12 as a more ...
A generalized retardation in skeletal maturation has different causative or etiological factors, these can be classified as follows:
chronic ill health
congenital heart disease (especially cyanotic)
chronic renal disease
inflammatory bowel disease
malnutrition: failure to thrive (FTT)
Delayed myocardial enhancement can occur in cardiac MR assessment due to a number of causes.
myocardial ischemia: typically subendocardial and follows a vascular territory 1
non-ischemic dilated cardiomyopathy
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)
The differential diagnosis for a dense base of the skull includes:
Van Buchem disease
The differential diagnosis of dense metaphyseal bands is wide.
chronic anemia, e.g. sickle cell disease, thalassemia
chemotherapy, e.g. methotrexate
growth acceleration lines following growth arrest due to systemic illness or stress in infancy or childhood, e.g...
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...
Diaphragmatic paralysis (also considered very similar to the term diaphragmatic palsy) can be unilateral or bilateral.
Clinical features are highly variable according to underlying etiological factor:
unilateral paralysis: asymptomatic in most of the patients as the othe...
Diaphragmatic rupture often results from blunt abdominal trauma. The mechanism of injury is typically a motor-vehicle collision.
Given that the most common mechanism is motor vehicle collisions, it is perhaps unsurprising that young men are most frequently affected. The estimated ...
Diaphyseal lesions are found centered in the diaphysis, the central tubular segment of long bones.
simple bone cyst
myeloma / plasmacytoma
round cell tumor, e.g. Ewing sarcoma (child...
Most tumors of the CNS can potentially occur in the temporal lobe, but entities with a predilection for being diagnosed in this location include:
pleomorphic xanthoastrocytoma (PXA)
dysembryoplastic neuroepithelial tumor (DNET)
multinodular and vacuolatin...
A small cardiothoracic ratio (CTR) is defined as <42%/0.42 when assessed on a PA chest radiograph, and is often called small heart syndrome. A pathologically-small heart is also known as microcardia.It can be due to/associated with a number of entities:
adrenal insufficiency, e.g. Addison disea...
Uterine 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
Differential diagnosis for calcified masses in the mandible includes:
calcifying odontogenic cyst (Gorlin cyst)
calcifying epithelial odontogenic tumor (Pindborg tumor)
Forefoot pain in the metatarsal region is a common complaint and may be caused by a number of conditions. It is worthwhile for a radiologist to have knowledge of the potential causes and their imaging features 1.
plantar plate disruption
The cul-de-sac, also known as the pouch of Douglas or rectouterine pouch, is an extension of the postero-inferior reflection of the peritoneal fold between the uterus (anteriorly) and rectum (posteriorly). It is the most inferior aspect of the peritoneal cavity and therefore the first location w...
The differential diagnosis of vascular calcification is very wide with many common and uncommon conditions.
end-stage renal failure 3
hemangioma; arteriovenous malformation
hyperparathyroidism, primary or secondary (renal osteodystrop...
An anterosuperior mediastinal mass can be caused by neoplastic and non-neoplastic pathology. As their name suggests, they are confined to the anterior mediastinum, that portion of the mediastinum anterior to the pericardium and below the level of the clavicles.
The differential diagnosis for a...
Diffuse airway narrowing can occur from a number of pathologies; these include:
granulomatosis with polyangiitis
various infections including
Diffuse alveolar hemorrhage (DAH) is a subset of diffuse pulmonary hemorrhage when bleeding is diffuse and directly into the alveolar spaces. It can occur in a vast number of clinical situations and can be life-threatening.
Blood tends to fill alveolar spaces at multiple sites.
A mnemonic to remember differentials causing diffuse bone marrow infiltration on MRI. It is best evaluated on T1 sequences which could be focal or diffuse. Focal infiltration seen in metastases and lymphoma. Diffuse pattern seen more in Multiple myeloma, Mastocytosis, Myelofibrosis, and Leukemia...
Diffuse atrophy of the cerebellum refers to a progressive and irreversible reduction in cerebellar volume. It is a relatively common finding and found in a wide variety of clinical scenarios.
Diffuse cerebellar atrophy can be difficult to distinguish from global cerebellar hypopla...
Diffuse colonic nodularity on barium enema or CT colonography has a range of possible etiologies:
lymphoid hyperplasia (tend to be small and discrete)
lymphoma (tend to be larger nodules and confluent)
urticaria (closely spaced polygonal lesions, history is often helpful)
Diffuse thickening of the gallbladder wall can occur in a number of situations:
gallbladder empyema 7
xanthogranulomatous cholecystitis 11
postprandial physiological state (pseudothickening)
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)
Diffuse pleural thickening refers to a morphological type of pleural thickening. It can occur from malignant as well as non-malignant causes, which include:
diffuse pleural fibrosis / fibrothorax 6
asbestos-related pleural disease: typically seen as a continuous sheet of pleural thickening oft...
Diffuse pulmonary hemorrhage (DPH) is a subtype of pulmonary hemorrhage where bleeding into the lung is diffuse. If the bleeding is into the alveolar spaces this can be further subclassified as diffuse alveolar hemorrhage (DAH).
While the exact presentation can vary is ha...
Diffuse pulmonary nodules are usually seen as multiple pulmonary nodular opacifications on a HRCT chest scan. They can signify disease processes affecting either the interstitium or the airspace. They can range from a few millimeters to up to 1 cm and when very small and numerous there can be so...
A number of differentials must be kept in mind while approaching diffuse or multiple pulmonary nodules. Interpretation is easier if nodules are the only abnormality.
These differentials can be narrowed down based on several criteria:
Based on appearance
Diffuse small bowel disease may be caused by a number of conditions may be generalized multisystem disorders or conditions that effect the bowel in a global fashion:
Diffuse T1 vertebral bone marrow signal loss is associated with replacement of fatty marrow by edema or cellular tissue. T1-weighted imaging without fat suppression is one of the most important sequences for distinguishing between normal and abnormal bone marrow. In the case of homogenous involv...
Conditions associated with diffuse tracheal narrowing or collapse include (in alphabetical order):
chronic obstructive pulmonary disease (COPD): saber sheath trachea
granulomatosis with polyangiitis
tracheobronchial tuberculosis 3
tracheomalacia/tracheobronchomalacia (due to col...
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
Disconnected pancreatic duct syndrome, also referred only as disconnected pancreatic duct, refers to the symptoms and complications due to the complete discontinuity of the main pancreatic duct between segments of viable secreting pancreatic tissue and the duodenum, usually seen as a sequela of ...
Discrete colonic ulcerations are nonspecific findings, and can be due to:
Disorganized or complex periosteal reaction has spicules with random orientation and appearance. It is often seen in highly aggressive processes.
It has been associated with:
malignant fibrous h...
Erosion or absence of the distal ends of the clavicles may be seen in a wide range of conditions.
atraumatic distal clavicular osteolysis: due to repetitive microtrauma; classically described in weightlifters, but can affect anyone performing repetiti...
The double bubble sign is seen in infants and represents dilatation of the proximal duodenum and stomach. It is seen in both radiographs and ultrasound, and can be identified antenatally 2.
Causes include 1,2:
A duodenal stricture refers to a segment of narrowing involving the duodenum. They can occur from a range of benign infective - inflammatory to malignant etiology. They can contribute to gastric outlet obstruction.
Dural arteriovenous shunts (DAVS) are rare congenital arteriovenous malformations (CAVMs). On the basis of clinical and anatomical features DAVS have three different types:
dural sinus malformations (DSMs)
infantile or juvenile DAVS (IDAVS)
adult DAVS (ADAVS)