Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and continuously improved upon by countless contributing members. Our dedicated editors oversee each edit for accuracy and style. Find out more about articles.

More than 200 results
Article

What constitutes a perfect case

So, what should a perfect case look like? Over time, the quality of contributions to Radiopaedia has grown, and what is considered a "perfect case" has also evolved. Please refer to the case publishing guidelines for a general set of instructions. You also can get a sense of how close your case ...
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Epididymal appendix

Epididymal appendices, also known as appendix of the epididymis or appendix epididymis, are testicular appendages and are less common than appendix testes 5. Epidemiology Epididymal appendices reported frequency on ultrasound is ~12.5% (range 6-17.6%) 3,5. Clinical presentation Normally, epi...
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Online resources

Online resources can be used as references as the source of images/diagrams with certain provisos.  Images Images are a great way of supplementing articles and cases and, in some instances, these can be obtained from other sites and uploaded to Radiopaedia.org provided they are copyright-free ...
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Scalpel sign (spinal cord)

The scalpel sign is described in dorsal thoracic arachnoid web on sagittal MRI spine studies. It relates to focal distortion of the thoracic cord, appearing anteriorly displaced. The appearance of the cord resembles the profile of a surgical scalpel with the blade pointing posteriorly 1. It is...
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Tetralogy of Fallot

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart condition with many cases presenting after the newborn period. It has been classically characterized by the combination of ventricular septal defect (VSD), right ventricular outflow tract obstruction (RVOTO), overriding aorta...
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Double posterior cruciate ligament sign

The double posterior cruciate ligament (PCL) sign appears on sagittal MRI images of the knee when a bucket-handle meniscal tear (medial meniscus in 80% of cases) flips towards the center of the joint so that it comes to lie anteroinferior to the posterior cruciate ligament (PCL) mimicking a seco...
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Adrenal gland

The adrenal (suprarenal) glands (often shortened to just the adrenals) are paired organs of the endocrine system, often asymmetric in shape.  Gross anatomy The adrenal glands are located superior and anteromedial to the kidneys, within the perirenal space, and enclosed by perirenal fascia. Eac...
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Cephalocele

Cephalocele refers to the outward herniation of CNS contents through a defect in the cranium. The vast majority are midline. Epidemiology The estimated incidence is 0.8-4:10,000 live births 13 with a well recognized geographical variation between types; however, this has been speculated to be ...
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Pulmonary arterial aneurysm

Pulmonary arterial aneurysms refer to a focal dilatation of the pulmonary arterial system. Epidemiology Overall it is considered a rare entity with autopsy prevalence rates of around 1 in 14,000 to 100,000 4,5. Pathology A true pulmonary artery aneurysm results from dilatation of all three l...
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Right-sided aortic arch

Right-sided aortic arch is a type of aortic arch variant characterized by the aortic arch coursing to the right of the trachea. Different configurations can be found based on the supra-aortic branching patterns, with the two most common patterns being the right-sided aortic arch with mirror imag...
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Pituitary region mass with intrinsic high T1 signal

Pituitary region masses with intrinsic high T1 signal, also referred to as suprasellar hotspots, are relatively frequently encountered, and the presence of high T1 signal narrows the differential somewhat.  Differential diagnosis The differential can be divided by the substance causing the T1 ...
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Scaphoid impaction syndrome

Scaphoid impaction syndrome is a clinical syndrome characterized by pain or wrist tenderness caused by an impaction of the dorsal rim of the scaphoid against the dorsal lip of the radius in the setting of forced wrist hyperextension. It can occur as a consequence of repetitive stress or as a sin...
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Congenital anomalies of the posterior atlas arch

Congenital anomalies of the posterior arch of the atlas (C1) are relatively common anomalies. They may range from partial defects presenting as clefts to complete absence of the posterior arch (aplasia). These anomalies are classified according to Currarino (see below). It should not be confuse...
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Windowing (CT)

Windowing, also known as grey-level mapping, contrast stretching, histogram modification or contrast enhancement is the process in which the CT image greyscale component of an image is manipulated via the CT numbers; doing this will change the appearance of the picture to highlight particular st...
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Eggshell calcification (lymph nodes)

Eggshell calcification refers to fine calcification seen at the periphery of a mass and usually relates to lamellar lymph node calcification. For similar appearance in the breast, see eggshell calcification (breast). Terminology In 1967 Jacobsen and Felson published criteria to help "avoid ove...
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Mesenteric ischemia

Mesenteric ischemia, also commonly referred to as bowel or intestinal ischemia, refers to vascular compromise of the bowel and its mesentery that in the acute setting has a very high mortality if not treated expediently. Mesenteric ischemia is far more commonly acute than chronic in etiology. Th...
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Major and minor edits

The terms major edit and minor edit are used to describe article edits and are used in a variety of ways on the site. They focus on change of meaning, not necessarily length. Minor edits Minor edits are changes that do not significantly alter the substance or meaning of the content. They are t...
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Langerhans cell histiocytosis (gastrointestinal manifestations)

Gastrointestinal manifestations of Langerhans cell histiocytosis (LCH) involve the proliferation of Langerhans cells in the gastrointestinal tract 1-3. LCH usually occurs as part of multi-system disease (‘disseminated form’) in the pediatric population 4,5 but can also occur as a single-system d...
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Petrous apex cephalocele

Petrous apex cephalocele is a rare form of cephalocele centered typically in the posterolateral part of Meckel cave with variable extension into the petrous apex. They can be unilateral or bilateral (commoner). Epidemiology There may be a slight female predilection. Clinical presentation The...
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Percutaneous nephrostomy

Percutaneous nephrostomy is a form of nephrostomy in which percutaneous access to the kidney is achieved under radiological guidance. The access is then often maintained with the use of an indwelling catheter. Indications Percutaneous nephrostomy is usually reserved for when retrograde approac...

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