Articles

Gastric metastases are rare, found in less than 2% of patients who die of a carcinoma 6. Epidemiology Usually affects the middle-aged and elderly population. Affects males and females equally without predilection. Clinical presentation The patient may be asymptomatic, but the most common sig...

Intradiploic epidermoid cysts refer to epidermoid cysts that occur in the diploë of the skull. Clinical presentation Painless slowly progressive scalp swelling. Pathology epidermoid cysts may be congenital (most common, arising from ectodermal inclusion during neural tube closure and subsequ...

The atlas (plural: atlases) is the first cervical vertebra, commonly called C1. It is an atypical cervical vertebra with unique features. It articulates with the dens of the axis and the occiput, respectively allowing rotation of the head, and flexion, extension and lateral flexion of the head. ...

Fat embolism syndrome (FES) is an uncommon clinical manifestation of a minority of individuals who have fat emboli. It is the result of innumerable small fat emboli leading to a multisystem dysfunction, classically characterized by the triad of: respiratory distress cerebral abnormalities pet...

Pulmonary fat embolism is a specific subtype of pulmonary embolism where the embolic particles are composed of fat. Pathology It usually occurs in the context of a long bone fracture and may occur in 1-3% of patients with simple tibial or femoral fractures and up to 20-33% of individuals with ...

The grey matter heterotopias are a relatively common group of conditions characterized by interruption of normal neuronal migration from near the ventricle to the cortex, thus resulting in "normal neurons in abnormal locations" 2. They are a subset of disorders of cortical formation 3-4. Grey m...

X-ray artifacts can present in a variety of ways including abnormal shadows noted on a radiograph or degraded image quality, and have been produced by artificial means from hardware failure, operator error and software (post-processing) artifacts.  There are common and distinct artifacts for fi...

Riedel lobe is a common anatomical variant of the liver to be aware of because it can simulate a mass. Its misidentification as a pathologic abdominal mass has led to surgery. Pathology can also occur within it (e.g. malignancy or even torsion) and cause atypical hepatic symptoms low in the pelv...

Per-oral esophageal myotomy (POEM) is a natural orifice endoscopic surgery that has been gaining increasing use as an alternative to traditional esophageal myotomies (e.g. Heller myotomy and Nissen fundoplication) to treat achalasia by weakening the lower esophageal sphincter. Technique The en...

Likelihood ratios (LR) are an alternative to positive and negative predictive values for estimating the likelihood of disease after diagnostic testing. The general formula for a likelihood ratio is the probability (P) that someone with a disease will have a particular test result divided by the ...

Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, is a syndrome with signs and symptoms of increased intracranial pressure but where a causative mass or hydrocephalus is not identified. Terminology The older term benign intracranial hypertension is generally frowne...

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. They account for ~5% of all sarcomas and are mostly found within the stomach and mid-distal small bowel. They respond remarkably well to chemotherapy. Terminology Previously these tumo...

Acute appendicitis (plural: appendicitides) is an acute inflammation of the vermiform appendix. It is a very common condition in general radiology practice and is one of the main reasons for abdominal surgery in young patients. CT is the most sensitive modality to detect appendicitis. Terminolo...

The skull base angle (of Boogard) allows the diagnosis of platybasia and basilar kyphosis. There are several different techniques that may be used on sagittal images from MRI or CT. Traditionally, basal angle measurements were based on plain skull images. With the advent and generalization of M...

Recurrent artery of Heubner, also known as the medial striate artery or long central artery, is the largest perforating branch from the proximal anterior cerebral artery (ACA) and is the only one routinely seen on angiography. Gross anatomy Origin and course The origin is from the anterior ce...

Hypothesis testing is a statistical method used to evaluate clinical trial results and consists of 4 steps. Step 1 Specify the null hypothesis (H0) and the alternative hypothesis (HA). The null hypothesis is that there is no difference between groups being evaluated, while the alternative hypo...

The anterior cerebral artery (ACA), along with the middle cerebral artery (MCA) forms at the termination of the internal carotid artery (ICA). It is the smaller of the two and arches anteromedially to pass anterior to the genu of the corpus callosum, dividing as it does so into its two major bra...

Primary lung cancer is a broad term referring to the main histological subtypes of primary lung malignancies that are mainly linked with inhaled carcinogens, with tobacco smoke being a key risk factor.  This article will broadly discuss all the histological subtypes as a group, focussing on the...

A patent urachus is one of the spectrum of congenital urachal anomalies. It has occasionally been termed "urachal fistula". Clinical presentation A patent urachus is often diagnosed in neonates when urine is noted leaking from the umbilicus. The umbilicus may also have an abnormal appearance o...

Intracranial arterial variants, of which there are many, are collectively common. Their clinical significance may be variable but knowledge and recognition of these variants is fundamental, especially if surgical or endovascular treatments (e.g. for acute stroke, aneurysms or other vascular path...