Articles

External auditory canal exostoses, also known as surfer's ear, are benign bony overgrowths of the bony external auditory canal brought about by exposure to cold wind and water combined. Epidemiology The estimated prevalence in cold-water surfers is thought to range between 70-80% 5,6,8. Clini...

Heel fat pad syndrome, also known as plantar fat pad syndrome or heel fat pad atrophy is a common but not well-known cause of heel pain in the adult population. Epidemiology Heel fat pad syndrome is common. It is the second most common cause of plantar heel pain after plantar fasciitis. It is ...

Portal venous flow is normally towards the liver (hepatopetal), with the normal main portal vein peak systolic velocities usually measuring 20-40 cm/s. In pathological situations, the flow velocity may decrease or even invert resulting in hepatofugal flow. The flow waveform is usually smooth b...

This is a basic article for medical students and other non-radiologists Chest x-ray lines and tubes can be easily assessed and should be the first thing that you look at when reviewing a chest x-ray. Assessment of their position is important, but they also give you an idea about how sick the pa...

The basilar transverse fissure, also known as Saucer's fissure, is a potential channel through the clivus in the basilar part of the occipital bone. It is considered a normal anatomical variant and should not be confused with clival clefts that can be seen with certain syndromes such CHARGE synd...

Splenic epithelial cysts, also known as splenic epidermoid cysts or primary splenic cysts, are unilocular fluid lesions with thin and smooth walls and no enhancement. They represent ~20% of cysts found in the spleen, and are usually an innocuous incidental imaging finding. Note that most (~80%)...

Splenic pseudocysts, also known as secondary splenic cysts, are acquired cystic lesions not delineated by a true epithelial wall. They represent the majority of the splenic cystic lesions, corresponding to approximately 80% of them (cf. splenic epithelial cysts). The main causes are:  splenic t...

Doppler shift or Doppler effect is defined as the change in frequency of sound wave due to a reflector moving towards or away from an object, which in the case of ultrasound is the transducer. Terminology When sound of a given frequency is discharged and subsequently reflected from a source th...

Modified Choi classification of common bile duct duplication is a widely used system for classifying the rare duplication of the extrahepatic biliary tree. 1-3: type I: distal septum splitting the bile duct lumen type II: bifurcation of the distal bile duct with each lumen draining independent...

Dual-energy CT has a number of clinical applications in the assessment of the musculoskeletal system particularly in the realm of artefact reduction and material composition. Detection of bone marrow edema Similar to the concept of using virtual non-contrast imaging, virtual non-calcium images...

The amplitude and intensity of ultrasound waves decrease as they travel through tissue, a phenomenon known as attenuation. Given a fixed propagation distance, attenuation affects high frequency ultrasound waves to a greater degree than lower frequency waves. This dictates the use of lower freque...

Refraction of a sound wave occurs if it travels between tissues with different propagation speeds. As the incident pulse or returning echo strikes an interface of different density or elasticity and therefore a different propagation speed, the direction of the wave changes according to Snell’s l...

Optical density is a measure of the degree of radiographic film darkening, and is related to the proportion of incident x-ray photons that are transmitted through the tissue and strike the film 1. Usage Optical density is used to describe the level of film exposure in film-screen radiography. ...

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...

Reverse rugger jersey spine describes the low endplate densities at multiple contiguous vertebral levels producing an alternating lucent-sclerotic-lucent appearance. It's the reverse counterpart of the Rugger jersey spine and also mimics the horizontal stripes of a rugby jersey. Pathology This...

The terms major edit and minor edit are used to describe article edits and are used in a variety of ways on the site. Minor edits Minor edits are changes that do not significantly alter the substance or meaning of the content. They are typically superficial in nature and focus on improving rea...

Elastofibroma dorsi, a benign soft-tissue tumor, is distinctly situated in the infrascapular or subscapular region, being bilateral close to a third of cases. On imaging, it presents as a poorly defined soft-tissue mass with CT attenuation closely resembling adjacent skeletal muscle. Epidemiol...

This article lists examples of normal imaging of the genitourinary tract and surrounding structures, divided by modality. Kidneys Plain radiograph KUB: example 1 abdominal x-ray: example 1 Intravenous Urogram (IVU) and Intravenous Pyelogram (IVP) IVU: example 1, example 2 Ultrasound rena...

Cracking thyroid is a term given to a very rare complication of thyroid fine needle aspiration (FNA) biopsy where there is acute pain and transient but marked thyroid swelling characterized by hypoechoic avascular septations on ultrasound 1,2. Onset is within a few minutes to a few hours post pr...

Connective tissue disease-interstitial lung disease (CTD-ILD) has various manifestations however the most frequent patterns seen on CT are NSIP or UIP. CTD-ILD should be suspected in younger patients especially women and never-smokers and particulary if there is involvement of pleura, airways or...