Articles

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...

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...

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...

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...

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...

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...

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...

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...

The axillary lymph nodes, also known commonly as axillary nodes, are a group of lymph nodes in the axilla that receive lymph from vessels that drain the arm, the walls of the thorax, the breast and the upper walls of the abdomen. Gross anatomy There are five axillary lymph node groups, namely ...

A cascade stomach, also referred to as a cup and spill configuration, is an anatomic variant of the stomach involving an angulation separating the fundus and body of the stomach. It is named for its appearance on contrast swallow, where contrast may fill the proximal stomach before spilling over...

Plagiarism, the passing of someone else's work as one's own, is unacceptable on Radiopaedia and will result in content not being able to be published. Existing plagiarised content that is discovered will be deleted.   We know you all want to help, and you may be tempted to "cut and paste" secti...

This article lists a series of labeled imaging anatomy cases by body region and modality. Brain CT head: non-contrast axial CT head: non-contrast coronal CT head: non-contrast sagittal CT head: non-contrast axial with clinical questions CT head: angiogram axial CT head: angiogram coronal ...

Positive predictive value (PPV) is one of the 4 basic diagnostic test metrics in addition to sensitivity, specificity and negative predictive value. Positive predictive value is a measure of how often someone who tests positive for disease actually has disease and is calculated by dividing the n...

Negative predictive value (NPV) is one of the 4 basic diagnostic test metrics in addition to sensitivity, specificity and positive predictive value. Negative predictive value is a measure of how often someone who tests negative for disease does not have disease and is calculated by dividing the ...

Diffuse/distal esophageal spasm (DOS) is a motility disorder of the esophagus. On barium swallow, diffuse esophageal spasm may appear as a corkscrew esophagus, but this is uncommon. Manometry is the gold standard diagnostic test. Diffuse esophageal spasm differs from hypercontracting esophagus ...