Pseudocirrhosis is a term used to recapitulate imaging findings of cirrhosis, but occurring in the setting of hepatic metastases. It is most commonly reported following chemotherapeutic treatment of breast cancer metastases, although has also been reported prior to treatment, and with other mali...
Here is a list of some of the most useful differential diagnoses in musculoskeletal imaging.
lucent/lytic bone lesions (FEGNOMASHIC)
multiple lucent/lytic bone lesions
benign lytic bone lesions in patients under 30
diffuse bony sclerosis
permeative process in bone
Nuchal fold thickness is a parameter that is measured on an obstetric second-trimester scan (at ~18-22 weeks) and should not be confused with nuchal translucency (which is measured in the first trimester).
The proposed aetiology of increased nuchal thickness is the result of hydrops...
Splenomegaly is a term which refers to enlargement of the spleen. The normal adult splenic length upper limit is usually around 12-15 cm. Also one should know how to calculate splenic index, volume and mass by CT and MR techniques. Massive splenomegaly is a term used when the spleen weighs >1000...
Endophthalmitis is a potentially sight-threatening condition that involves intraocular inflammation of any cause. It is distinguished from panopthalmitis in that is does not extend beyond the sclera. It is either infectious or noninfectious in aetiology, but in clinical practice, intraocular inf...
Diaphyseal lesions are unsurprisingly predominantly found centred in the diaphysis.
simple bone cyst
myeloma / plasmacytoma
round cell tumour, e.g. Ewing sarcoma (children)
Sclerotic clavicles have many causes:
trauma: fractured clavicle
arthritis: osteoarthritis, seronegative arthritides
osteitis condensans of the clavicle 1
The differential diagnosis for a dense base of the skull includes:
Van Buchem disease
Atraumatic or spontaneous splenic rupture is rare, especially when compared to traumatic splenic rupture.
The pathogenesis of atraumatic splenic rupture is not well understood. Splenomegaly is present in almost all patients (~95%), although rupture of normal spleens (both in size an...
Epiphyseal lesions comprise of tumours and other pathologies that occur around the epiphysis and any epiphyseal equivalent bone.
Common differential diagnoses include 2-4:
chondroblastoma: rare epiphyseal tumour found in young adults; it does not usually extend into the...
Fetal chylothorax is defined as the presence of lymphatic fluid within the pleural cavity.
may show echogenic fluid in the pleural cavities
Some of the de...
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 peritoniti...
Multiple criteria are used to detect extracapsular extension of prostate cancer. They include 3:
an irregular bulge in capsule
obliteration of the rectoprostatic angle
asymmetry of the neurovascular bundle
angulation/step-off appearance to the tumour
focal capsular retraction and or thicken...
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:
exostosis of the external audit...
Exophytic hepatic mass or tumour is a lesion which predominantly lies outside the margins of liver but originates from within the liver.
Causes include 1:
focal nodular hyperplasia
Hyperosmolar hyperglycaemic state (HHS) (previously known as hyperosmolar non-ketotic coma (HONK)) is a serious metabolic derangement that can occur in patients with diabetes mellitus, predominantly those with type 2. While there are no distinct imaging features, it is useful for a radiologist t...
Hyperdense pulmonary nodules are a subset of pulmonary nodules that have relatively increased attenuation, usually caused by calcification within the nodule. Here, we broadly refer to a nodule as a pulmonary opacity <30 mm.
calcified pulmonary nodules are a specific grou...
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...
High attenuation lymphadenopathy has been described with:
Kaposi sarcoma 1,6
angioimmunoblastic lymphadenopathy (AILD)
Kimura disease (due to nodal haemorrhage) 6
metastatic hypernephroma (presumed due to nodal haemorrhage) 6
If there is calcification associat...
Despite the vast majority of renal cancers being sporadic, there are a number of hereditary renal cancer syndromes:
von Hippel Lindau syndrome: predominantly clear cell type
tuberous sclerosis: predominantly clear cell type
hereditary leiomyomata renal cell cancer syndrome: described in ISUP ...
Hepatolithiasis is the presence of bile duct stones within the intrahepatic bile ducts, specifically before the confluence of the right and left hepatic ducts.
Hepatolithiasis is common Asia and the Pacific, with a prevalence of ~40%. It is rare in the West with a prevalence of ~...
Hepatic osteodystrophy is an often forgotten metabolic bone disease seen in patients with chronic liver disease, in particular cirrhosis, primary biliary cirrhosis, and primary sclerosing cholangitis. These patients have increased risk factors for developing osteoporosis such as hypogonadism, al...
A hepatic lymphangioma is a rare benign condition that corresponds to focally dilated lymphatic channels in the liver.
Most cases are asymptomatic.
A lymphangioma is a benign lesion that can occur at almost any location in the body. Hepatic involvement is les...
A hallux valgus is a fixed abduction of the first metatarsophalangeal joint of the great toe. It is usually due to metatarsus primus varus which is a medial deviation or adduction of the first metatarsal with an increased first - second metatarsal angle.
Haglund deformity, also known as a pump bump or Bauer bump or Mulholland deformity, is defined as bony enlargement formed at posterosuperior aspect of the calcaneum. This deformity leads to retrocalcaneal bursitis.
It may result secondary to chronic pressure of rigid shoes.
Haemothorax literally means blood within the chest, is a term usually used to describe a pleural effusion due to accumulation of blood. If a haemothorax occurs concurrently with a pneumothorax it is then termed a haemopneumothorax.
A tension haemothorax refers to haemothorax that results from ...
Haemosiderosis is a general term referring to accumulation of haemosiderin, which particularly occurs in the reticuloendothelial system (RES) and does not cause organ damage.
Some causes include:
mainly depositional siderosis in RES
if >40 units transfused: t...
Haemoptysis refers to coughing out blood. Generally, it appears bright red in colour as opposed to blood from gastrointestinal tract which appears dark red. It is considered an alarming sign of a serious underlying aetiology.
Massive haemoptysis is referred to as expectoration of >...
Haemopneumothorax is a term given when there is concurrent presence of a haemothorax and well as a pneumothorax. It is a variant of a hydropneumothorax.
Approximately 5% of patients with pneumothorax will have concomitant haemothorax 6 .
It is typically seen in the se...
There are a number of lesions that appear hyperechoic on ultrasound. Such lesions can be either completely or partly hyperechoic and comprise of both benign and malignant entities.
fat containing breast lesions
lipoma of the breast
fibroadenolipoma (hamartoma) of the breast
Hydroxyapatite crystal deposition disease (HADD) is a disease of uncertain aetiology characterised by periarticular and intra-articular deposition of hydroxyapatite (HA) crystals.
The shoulder is the most frequently involved site with classic calcific tendinitis presentation.
The CNS manifestations of HIV/AIDS (neuroAIDS) occur secondary to a wide range of neurodegenerative, infectious, inflammatory, or neoplastic processes.
Since the introduction of highly active antiretroviral therapy (HAART) in 1996, there has been a shift in the epidemiology of CN...
Cardiovascular manifestations are seen with increased frequency in the HIV/AIDS adult population, and include:
dilated cardiomyopathy (prevalence 8-30%)
endocarditis: either infective or non-bacterial thrombotic (marantic) which is associated with malignancy or HIV wasti...
Haemolytic anaemia is a form of anaemia where red blood cells (RBCs) are destroyed either intravascularly or extravascularly.
The patient presents with anaemia and jaundice. Diagnosis is based on several laboratory parameters 1:
increased unconjugated bi...
Hepatisation of the gallbladder is a sonographic entity in which the gallbladder lumen is entirely filled with tumefactive sludge giving the gallbladder a similar appearance to liver parenchyma. It is one of the causes of non-visualisation of the gallbladder on sonography.
In the set...
Haematospermia refers to the presence of blood in semen or ejaculatory fluid. It is a symptom that can cause great anxiety in patients despite commonly being of benign aetiology.
urogenital infections including sexually transmitted disease
commonest cause in patients <40 ...
There are many thoracic complications that can occur following haematopoietic stem cell transplantation. These can precipitate during various stages following transplantation and can be either infectious or noninfectious.
Hangman fracture, also known as traumatic spondylolisthesis of the axis, is a fracture which involves the pars interarticularis of C2 on both sides, and is a result of hyperextension and distraction.
Post-traumatic neck pain after a high-velocity hyperextension injury is ...
Haemoperitoneum is the presence of blood within the peritoneal cavity.
penetrating or non-penetrating abdominal trauma (often with associated organ injury) 1
ruptured ectopic pregnancy
ovarian cyst rupture
aneurysm or pseudoaneurysm rupture
Haemopericardium refers to the presence of blood within the pericardial cavity, i.e. a sanguineous pericardial effusion. If enough blood enters the pericardial cavity, then a potentially fatal cardiac tamponade can occur.
There is a very long list of causes 1,4 but some o...
Cardiac involvement in haemochromatosis typically occurs with primary haemochromatosis, as the organ is usually spared in the secondary form of the disease.
Cardiac involvement occurs in approximately 15-20% of the patients with haemochromatosis.
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...
Elevated hemidiaphragms can result from many causes:
above the diaphragm 1
decreased lung volume
phrenic nerve palsy
contralateral stroke: usually middle cerebral artery distribut...
Left upper lobe collapse has distinctive features but can be challenging to identify on chest radiographs by the uninitiated.
For a general discussion refer to the article on lobar collapse.
The left upper lobe collapses anteriorly becoming a thin sheet...
Epididymal masses are most commonly encountered on ultrasonography. Most epididymal masses are benign; malignant lesions are rare.
adenomatoid tumour of the scrotum (most common epididymal mass 4)
sperm granulomas / post vasectomy gra...
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.
chronic epididymitis: e.g. bacterial, granulomatous (TB) or genital filariasis
Thyrotoxicosis is a hypermetabolic clinical syndrome caused by a pathological excess of circulating free T4 (thyroxine) and/or free T3 (tri-iodothyronine).
Although commonly done, thyrotoxicosis should not be confused nor synonymised with hyperthyroidism, the latter of which is a g...
A number of inflammatory conditions can affect the thyroid gland, which are commonly described as thyroiditides:
acute suppurative thyroiditis (AST)
subacute lymphocytic thyroiditis: silent thyroiditis or painless subacute thyroiditis
Cardiovascular (cardiac) shunts are abnormal connections between the pulmonary and systemic circulations. Most commonly they are the result of congenital heart disease.
Blood can either be shunted from the systemic circulation to pulmonary circulation (i.e. 'left-to-right shunt') or ...
Carotid artery stenosis also referred as extracranial carotid artery stenosis, is usually caused by an atherosclerotic process and is one of the major causes of stroke and transient ischemic attack (TIA) 1.
This article refers to stenosis involving carotid bulb and the proximal segment of inte...
Tension pneumothoraces occur when intrapleural air accumulates progressively in such a way as to exert positive pressure on mediastinal and intrathoracic structures. It is a life-threatening occurrence requiring rapid recognition and treatment is required if a cardiorespiratory arrest is to be a...
Trauma is a leading cause of mortality in pregnancy. Pregnancy increases the incidence and severity of abdominal trauma in females.
Trauma affects up to 7% of pregnancies, and the incidence of pregnancy in level 1 trauma patients is estimated to be ~2% 1.
Gunshot injuries often require imaging assessment, and this evaluation has both clinical relevance (assessment of organ damage, surgical planning and prognostication), and often also forensic implications.
Incidence of gunshot injuries to the head is increasing in some countries, ...
Conditions associated with bone deformity from softening includes:
bowing of long bones
biconcave vertebral bodies / codfish vertebra
Tear drop sign of the superior mesenteric vein (SMV) is one of the important signs in the local staging of pancreatic adenocarcinoma. Its importance lies in its diagnostic, as well as prognostic, significance. This sign is used in assessing the resectability of pancreatic cancer.
There are a number of neoplasms that can involve the vermiform appendix, some of which are peculiar to this site.
Tumours involving the appendix have been found in only about 1% of all appendectomy specimens 9. Epithelial neoplasms and neuroendocrine tumours represent the vast maj...
Transient lesions of the splenium of the corpus callosum, also known as mild encephalitis/encephalopathy with a reversible isolated SCC lesion (MERS), are occasionally encountered on MRI studies and may be due to a number of underlying aetiologies.
Unlike other causes of ...
Crazy paving refers to the appearance of ground-glass opacity with superimposed interlobular septal thickening and intralobular reticular thickening, seen on chest HRCT. It is a non-specific finding that can be seen in a number of conditions.
Swan neck deformity is a deformity of the digits that consists of:
hyperextension of the proximal interphalangeal (PIP) joints
compensatory flexion of the distal interphalangeal (DIP) joints
Swan neck deformity is seen in 3,4:
rheumatoid arthritis (classical association)
Mucoid impaction, also referred to as mucus plugging or a bronchocele, is a commonly encountered pathological feature seen in chest radiography and thoracic CT scanning. It is usually defined as airway filling by mucoid secretions and can be obstructive or non-obstructive.
Bronchial atresia is a developmental anomaly characterised by focal obliteration of the proximal segment of a bronchus associated with hyperinflation of the distal lung.
On imaging, it commonly presents as a proximal focal tubular shaped opacity radiating from the hilum associated with a dista...
Hepatic attenuation on CT, reflected by Hounsfield values, depends on a combination of factors including the presence or absence, as well as the phase, of IV contrast administration.
Allowing for all these factors, the mean unenhanced attenuation value is around 55 HU 4.
Tonsillar herniation is a type of cerebral herniation characterised by the inferior descent of the cerebellar tonsils below the foramen magnum.
The terminology of caudally displaced tonsils is discussed in the article on cerebellar tonsillar ectopia.
It is a secondary sign of signif...
Medical devices in the neck are regularly observed by radiologists on plain film and CT reporting. They include devices which pass through the neck onto the chest and stomach.
Vascular access devices
peripherally inserted central catheters (PICC)
central venous catheters
Gastric band malposition is an early complication from laparoscopic gastric band procedures which are performed for obesity. It can occur as in isolation or with other gastric band complications.
As surgical experience of lap gastric banding has accumulated, it has become a relatively rare comp...
An Erlenmeyer flask deformity refers to a radiographic appearance typically on a femoral radiograph demonstrating relative constriction of the diaphysis and flaring of the metaphysis.
lysosomal storage disease
Gaucher disease - osteopenia with Leg...
The differential diagnosis of a solitary sclerotic bone lesion is heavily influenced by the age of the patient, and includes:
when solitary may be the only one visible of many or the only one imaged
enostosis (bone island)
Soft-tissue sarcomas are a heterogeneous group of malignant tumours of mesenchymal origin (sarcoma) that originate from the soft tissues rather than bone. They are classified on the basis of tissue seen on histology. The commoner sarcomas in the adult and paediatric population are listed below.
Regular, smooth generalised thickening
congestive cardiac failure (CCF)
anticoagulation or bleeding diathesis
IgA vasculitis (Henoch-Schonlein purpura)
Gastric band erosion or penetration is a potentially serious complication following laparoscopic gastric band surgery for obesity.
Gastric band erosion is a delayed complication observed in between 0.3-14% of patients 1-2.
Patients often present non-specif...
Skeletal dysplasias (osteochondrodysplasias) refer to an abnormality in bone formation. There is a very wide clinicopathological spectrum and any part of the skeleton can be affected.
The overall prevalence is estimated at ~2 per 10,000 live births 3.
At least 3...
Colpocephaly is a descriptive term to a disproportionate prominence of the occipital horns of the lateral ventricles. It can result from a wide range of congenital insults.
Patient may present with motor abnormalities, cognitive deficit, visual abnormalities, and seizures...
Generalised osteopenia refers to osteopenia diffusely affecting the bones.
The differential diagnosis is wide and includes includes:
osteoporosis: decreased osteoid production
osteomalacia: undermineralisation of osteoid
Basal ganglia calcification is common and is seen in approximately 1% of all CT scans of the brain, depending on the demographics of the scanned population. It is seen more frequently in older patients and is considered a normal incidental and idiopathic finding in an elderly patient but should ...
Posterior shoulder dislocations are far less common than anterior shoulder dislocations and can be difficult to identify if only AP projections are obtained. I high index of suspicion is helpful.
Posterior shoulder dislocations account for only 2-4% of all shoulder dislocations (t...
Airway foreign bodies in children are potentially fatal, which is why immediate recognition is important. Unfortunately, delayed diagnosis is common.
Children under the age of four years are at increased risk of foreign body (FB) aspiration, with a slight male predominance 1.
Kim lesions are superficial tears between the posterior glenoid labrum and glenoid articular cartilage without labral detachment. Failure to identify and treat this lesion may lead to permanent posterior instability.
It typically results from a postero-inferiorly directed force on t...
The capitolunate angle is the angle between the long axis of the capitate and the mid axis of the lunate on the sagittal imaging of the wrist. In a normal situation it should be less than 30o in the resting (neutral) position.
The angle is increased in carpal instability such as with a dorsal i...
Reverse bat wing pulmonary opacities refer to peripheral opacities of the lungs, sparing the perihilar region. It is a relatively unusual appearance with a relatively narrow differential:
chronic eosinophilic pneumonia
organising pneumonia (formerly bronchiolitis obliterans with organising pne...
Ultrasound appearance of liver metastases can have bewildering variation.Caveat: Presence of hepatic steatosis can affect the sonographic appearance of liver lesions.
Patterns do exist between ultrasound appearance of the liver metastases and the likely primary, which is sometimes helpful in di...
Visceral artery aneurysms (VAA) are abnormal focal dilatations of arteries supplying abdominal organs. Visceral artery aneurysms include both true aneurysms and pseudoaneurysms.
Owing to different clinical manifestations and a unique, specific, pathology, renal artery aneurysms are discussed se...
There is a wide range of causes for subarachnoid FLAIR hyperintensity, both pathological and artifactual.
FLAIR vascular hyperintensities in acute stroke 1,4,8
moya moya disease
This article aims to be a collection of articles that represent central nervous system infectious (CNS) diseases.
The organisms involved in CNS infections vary depending on the specific location of infection. Bacteria, viruses, fungi, parasites, and prions can all ...
Small bowel or mesenteric ischaemia may be a life-threatening condition, arising from any one of numerous causes of disturbance of the normal blood flow through the small bowel wall.
It can be divided into acute and chronic forms, with the main underlying aetiologies (each discussed...
Porcelain left atrium, also known as coconut left atrium, is a term used when a large part of or the entire left atrial wall becomes calcified. It can occur as a rare consequence of endocarditis (with underlying rheumatic heart disease). It has also been described in the setting of end-stage ren...
Shortening of the fourth/fifth metacarpals is seen in a variety of apparently disparate conditions.
Common causes 2:
post-infective (e.g. osteomyelitis, yaws, tuberculosis dactylitis)
Powers ratio is a measurement of the relationship of the foramen magnum to the atlas, used in the diagnosis of atlanto-occipital dissociation injuries.
The ratio, AB/CD, is measured as the ratio of the distance in the median (midsagittal) plane between the:
basion (A) and the posterior spinola...
Skeletal “don’t touch” lesions (also called leave me alone lesions) are so radiographically characteristic lesions that an additional diagnostic tests such as a biopsy are unnecessary and can be frankly misleading and lead to additional unnecessary surgery. Thus a radiologic diagnosis should be ...
Extension tear drop fracture typically occurs due to forced extension of the neck with resulting avulsion of the anteroinferior corner of the vertebral body. Extension teardrop fractures are stable in flexion, and unstable in extension as the anterior longitudinal ligament is disrupted. Extensio...
Pulmonary aspergillosis is a collective term used to refer to a number of conditions caused by infection with a fungus of the Aspergillus species (usually Aspergillus fumigatus).
There are a number of recognised pulmonary forms, the number depending on the author 1,3-4 . Each form has specific ...
Gynaecomastia refers to a benign excess of the male breast tissue, that is usually reversible. It is not a risk factor per se for developing male breast cancer.
While it can occur at any age, it tends to have greater prevalence in two groups: adolescent boys and older men (some pu...
Ground glass opacification/opacity (GGO) is a descriptive term referring to an area of increased attenuation in the lung on computed tomography (CT) with preserved bronchial and vascular markings. It is a non-specific sign with a wide aetiology including infection, chronic interstitial disease a...
Prostatic utricle cyst (PUC) is an area of focal dilatation that occurs within the prostatic utricle.
They are midline cystic masses in the male pelvis and can be very difficult or impossible to distinguish from a Mullerian duct cyst.
Utricle cysts are most often detected in the ...