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 edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

41 results found
Article

ABC/2

ABC/2 is a fast and simple method for estimating the volume of intracerebral haemorrhage (or any other ellipsoid lesion for that matter) which does not require volumetric 3D analysis or software. Intracerebral haemorrhage volume is an important predictor of morbidity and mortality (and thus tria...
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Ageing blood on MRI

The imaging characteristics of blood on MRI can be variable and change with the age of the blood. In general, five stages of haematoma evolution are recognised: hyperacute intracellular oxyhaemoglobin isointense on T1 isointense to hyperintense on T2 acute (1 to 2 days) intracellular deo...
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Canadian CT head rule

The Canadian CT head rule (CCTHR) is a validated clinical decision rule to determine the need for CT head in adult emergency department patients with minor head injuries. Inclusion criteria Patient has suffered minor head trauma with resultant: loss of consciousness GCS 13-15 confusion amn...
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Cases in radiology (video tutorials)

The cases featured in these video lectures are specifically selected to teach important concepts in radiology over a broad range of topics. The tutorials vary in difficulty from basic to advanced. For maximum learning, try the cases for yourself in Radiopaedia quiz mode first.  We love this ser...
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Cerebral oedema (summary)

This is a basic article for medical students and other non-radiologists Cerebral oedema describes the collection of additional fluid within the white matter of the brain. It is the brain's response to an insult and may take one of two broad forms: vasogenic (white matter) and cytotoxic (grey an...
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CHALICE rule

The Children’s Head injury ALgorithm for prediction of Clinically Important Events (CHALICE) clinical decision rule was developed to predict clinically important brain injuries in children with head trauma. This rule identifies high-risk criteria and divides them into history, examination and me...
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Concurrent suprasellar and pineal region lesions (differential)

Concurrent suprasellar and pineal region lesions have a relatively short differential to be considered, including:  germinoma other germ cell tumours choriocarcinoma embryonal cell carcinoma yolk sac tumour (endodermal sinus tumour) primary CNS lymphoma cerebral metastasis quadrilateral ...
Article

CT angiography of the cerebral arteries

CT angiography of the cerebral arteries is a noninvasive technique allows visualization of the internal and external carotid arteries and vertebral arteries and can include just the intracranial compartment or also extend down to the arch of the aorta. By using multidetector CT (MDCT) after int...
Article

CT cisternography

Computed tomography (CT) cisternography is an imaging technique used to diagnose CSF rhinorrhoea or CSF otorrhoea (CSF leaks), as CT allows the assessment of the bones of the base of skull.  Procedure pre-contrast CT is performed with thin slices 3-10 mL of an iodinated non-ionic low-osmolar ...
Article

CT head (an approach)

The approach taken to interpreting a CT scan of the head is no doubt different depending on the circumstances and the reading clinician, however, most radiologists will go through the same steps. What follows is merely a suggested approach to interpreting a CT of the head.  An important aspect ...
Article

CT head (subdural window)

The subdural (blood) window can be used when reviewing a CT brain as it makes intracranial haemorrhage more conspicuous, and may help in the detection of thin acute subdural haematomas that are against the calvaria. It is a wider setting than the standard non-contrast window, and there are a num...
Article

CT perfusion in ischaemic stroke

CT perfusion in ischaemic stroke has become established in most centres with stroke services as an important adjunct, along with CT angiography (CTA), to conventional unenhanced CT brain imaging.  It enables differentiation of salvageable ischaemic brain tissue (the penumbra) from irrevocably d...
Article

Denver criteria for blunt cerebrovascular injury

The Denver criteria are a set of screening criteria for blunt cerebrovascular injury (BCVI) in trauma used to reduce the need for CT angiography and its associated radiation exposure.  Screening criteria The screening protocol criteria 1,3 for BCVI are divided into signs and symptoms of BCVI a...
Article

Extradural haematoma vs subdural haematoma

Differentiating extradural (EDH) from subdural (SDH) haemorrhage in the head is usually straightforward, but occasionally it can be challenging. SDHs are more common and there are a few distinguishing features which are usually reliable. Pathology History and mechanism of injury Extradural ha...
Article

Focal areas of signal intensity (brain)

Focal areas of signal intensity (FASI), alternatively called focal abnormal signal intensity or unidentified bright objects (UBO), are bright areas on T2-weighted images commonly identified in the basal ganglia (often the globus pallidus), thalamus, brainstem (pons), cerebellum, and subcortical ...
Article

Frontal horn width to intercaudate distance ratio

Frontal horn width to intercaudate distance ratio (FH/CC) is used in assessing patients with suspected Huntington disease.  On the same axial plane obtained on the ACPC (anterior commissure and posterior commissure) line, the ratio between the distance between the caudate heads (where they are ...
Article

Glioblastoma vs cerebral metastasis

Differentiating a glioblastoma (GBM) from a cerebral metastasis is a frequent challenge, with profound surgical, workup and treatment implications. Unfortunately distinguishing between the two entities is not always straightforward.  This article addresses helpful imaging features to aid in dis...
Article

Global cortical atrophy scale

The global cortical atrophy (GCA) scale, also known as the Pasquier scale, is a qualitative rating system developed to assess cerebral atrophy, especially in the context of neurodegenerative diseases. It evaluates atrophy in 13 brain regions assessed separately in each hemisphere and resulting i...
Article

Haemorrhagic infarct vs intracerebral haemorrhage

Haemorrhagic infarct or haemorrhagic transformation of an infarct is seen following breakdown of the lamina of the microvessels. Intracerebral haemorrhage (ICH) may overlap with a haemorrhagic infarct and hence needs to be differentiated as the line of treatment will vary. Differentiating poin...
Article

Haemorrhagic intracranial tumours

Various types of brain tumours may cause haemorrhage. Increased tumour vascularisation with dilated, thin-walled vessels and tumour necrosis are the most important mechanisms of haemorrhage. The list includes: glioblastoma pituitary adenoma ependymoma central neurocytoma choroid plexus carc...
Article

Imaging of gunshot injuries

Gunshot injuries often require imaging assessment, and this evaluation has both clinical relevance (assessment of organ damage, surgical planning and prognostication), and often also forensic implications. Epidemiology Incidence of gunshot injuries to the head is increasing in some countries, ...
Article

Intercaudate distance to inner table width ratio

Intercaudate distance to inner table width ratio (CC/IT) is used in assessing patients with neurodegenerative diseases that affect the caudate nuclei. It is best known for assessing individuals with suspected Huntington disease but is in no way specific for the diagnosis, also seen in other less...
Article

Interseptal distance

The interseptal distance (ISD) is a measurement used to assess septal area atrophy as a marker for neurodegenerative conditions in patients with memory problems 1. It is proposed that atrophy of the septal nuclei can commonly be seen in conditions associated with hippocampal atrophy, particular...
Article

Intracranial nonneoplastic cysts

Intracranial nonneoplastic cysts are common findings in magnetic resonance (MR) and computed tomographic (CT) brain scans. Location-based diagnostic approach A location-based approach is useful in establishing an appropriate diagnosis; some locations are virtually pathognomonic for certain les...
Article

Intradural spinal mass lesions (an approach)

Intradural spinal mass lesions are relatively uncommon, compared to intracranial or extradural masses, and can be challenging to diagnose. Additionally, the need for a pre-operative/non-operative diagnosis is in many ways greater as biopsy of lesions within the cord has the potential of devastat...
Article

Intraventricular masses (an approach)

The ventricular system of the brain plays host to a variety of unique tumours, as well as tumours that are more frequently seen elsewhere (e.g. meningiomas). Besides, some intra-axial (parenchymal) masses can be mostly exophytic and thus appear mostly intraventricular. A systematic approach taki...
Article

Medial temporal lobe atrophy score

The medial temporal lobe atrophy (MTA) score is useful in distinguishing patients with mild cognitive impairment and Alzheimer disease from those without impairment 2 is helpful in the assessment of patients with possible dementia (see neurodegenerative MRI brain - an approach). Classification ...
Article

Myelination pattern on MRI

Myelination of the brain during infancy progresses in an orderly and predictable fashion which can be assessed with MRI.  At term (40 weeks corrected gestation) only certain structures are myelinated: dorsal brainstem ventrolateral thalamus lentiform nuclei central corticospinal tracts pos...
Article

Neurodegenerative MRI brain (an approach)

Imaging of the brain in patients with suspected neurodegenerative conditions is common and challenging, as in patients with subtle and equivocal signs and symptoms, the imaging findings are also subtle and equivocal. In many instances, by the time imaging findings are clear cut, then the patient...
Article

Optic nerve sheath diameter

Optic nerve sheath diameter has significance in the assessment of papilloedema in cases of elevated intracranial pressure. Pathology The optic nerve sheath demonstrates changes in diameter with CSF pressure changes as there is a layer of subarachnoid space between the nerve and its sheath, whi...
Article

PECARN traumatic brain injury algorithm

The PECARN (Paediatric Emergency Care Applied Research Network) traumatic brain injury algorithm is a clinical decision rule that aims to identify children at very low risk of clinically important traumatic brain injury (ci-TBI) 1. This validated paediatric algorithm predicts likelihood of the a...
Article

Pineal region (an approach)

A systematic approach to the pineal region is crucial as it is at the confluence of many intracranial structures/regions and is the site of origin of a number of unique pathologies as well as playing host to many entities which are more frequently encountered elsewhere. As such an understanding ...
Article

Pituitary MRI (an approach)

A systematic approach to the pituitary region is crucial as small lesions can have a profound impact on the patient, and can be subtle even on high quality dedicated MRI imaging. Successful assessment of the pituitary region relies not only on a clear understanding of the local anatomy but also ...
Article

RANO criteria for glioblastoma

Response assessment in neuro-oncology criteria (RANO), published in 2010 1, are used to assess response to first-line treatment of glioblastoma (as well as lower grade astrocytoma 3) and have largely superseded the older Macdonald criteria (which only dealt with glioblastoma multiforme) 2. For ...
Article

Sagittal midline of the brain (an approach)

The sagittal midline of the brain is one of the most important sectional planes in neuroimaging. A good working knowledge of the normal neuroanatomy of the sagittal midline is essential so that the subtle abnormalities that may manifest here can be recognised. The neuroembryological development...
Article

Spinal cord injury

Spinal cord injury (SCI) can be traumatic or non-traumatic (i.e. neoplastic/stenosis) but the syndromes associated with spinal cord injury can be seen in all aetiologies. Injury to the spinal cord can be incomplete or complete and depends upon the mechanism of injury. This is important as diffe...
Article

Supratentorial intracranial mass in an adult (an approach)

The identification of a supratentorial intracranial mass in an adult is a fairly common clinical scenario, the appropriate management of which relies heavily on preoperative imaging. Often important clues will be present in the clinical history (e.g. immunosuppression, systemic malignancy, durat...
Article

Tentorial angle

The tentorial angle is measured between a line connecting the nasion with the tuberculum sellae and the the angle of the straight sinus. Normally it should measure between 27° and 52°. Abnormalities of the posterior fossa / base of skull can alter this. For example this angle is elevated in ach...
Article

Tumour pseudoresponse

Tumour pseudoresponse, also known just as pseudoresponse, refers to the phenomenon of tumours appearing to respond to a specific treatment on imaging criteria, when the lesion actually remains stable or has even progressed. The term is largely used in brain tumours imaging follow-up, especially...
Article

Ventral cord syndrome

Ventral cord syndrome (also known as anterior cord syndrome) is one of the incomplete cord syndromes and affects the anterior parts of the cord resulting in a pattern of neurological dysfunction dominated by motor paralysis and loss of pain, temperature and autonomic function. Anterior spinal ar...
Article

Vermian maturity assessment (approach)

Radiological evaluation of the posterior fossa is an essential part of the routine fetal assessment, including vermian maturity assessment. Radiographic features Ultrasonography is a readily available diagnostic tool in the assessment of the fetal posterior fossa but is sometimes limited due t...

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