Articles

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...

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 ...

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...

Skull vault hemangiomas (SVH), or hemangiomas of the calvaria, are benign slow-growing vascular lesions affecting the skull diploe in any location. They have been more recently renamed osseous venous (low-flow) vascular malformations given their nonneoplastic nature, but "hemangioma" remains com...

Spatial resolution in CT is the ability to distinguish between object or structures that differ in density. A high spatial resolution is important for one to discriminate between structures that are located within a small proximity to each other.  Factors affecting CT spatial resolution field...

The normal distribution (or bell curve or Gaussian distribution) is a type of data spread that is encountered frequently in radiology and in other sciences. Data that are normally distributed can be evaluated using parametric statistics. When data are not normally distributed (e.g. skewed, or m...

The power of a clinical trial is the probability that the trial will find a difference between groups if there is one. Power can be defined as the probability of a true positive trial result and is often written as: power = (1 - β) where β is the probability of missing a difference between gro...

Patient confidentiality and anonymity are of paramount importance. Under no circumstances should any information be uploaded either in the patient's presenting symptoms, case description or images themselves that could identify an individual patient.  In short, nothing in your images or accomp...

Lingula (plural: lingulae) can refer to a number of different anatomical structures: lingula (mandible) lingula (lung) lingula (cerebellum) lingula (sphenoid bone) lingula (hyoid bone) History and etymology Lingula is the diminutive form of lingua, Latin for the tongue. Thus lingula is us...

The hyoid bone is a midline "U or horseshoe-shaped" bone that serves as a structural anchor in the mid-neck. It is the only bone in the human body that does not directly articulate with another bone (other than sesamoids). It is a place of convergence of multiple small neck muscles that permit t...

Bile duct strictures are problematic in terms of management and distinction between benign and malignant. Pathology Etiology There are numerous causes of biliary duct strictures, including 1,2: malignant cholangiocarcinoma involvement by pancreatic head adenocarcinoma involvement by ampul...

Right bundle branch block is a finding on electrocardiogram due to an interruption or alteration in the His-Purkinje system and is characterized by widened QRS complexes and changes in R and S wave vectors 1,2. It can be complete or incomplete, with incomplete being the more common form of prese...