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.
742 results found
Article
Sagittal vertical axis
Sagittal vertical axis/alignment (SVA) is one of the simplest and most widely used methods to assess sagittal balance 1-3.
Measurement
This measurement is performed on lateral standing full-length spine x-rays. A plumb line is drawn vertically from the middle of the C7 vertebral body 1,2 or th...
Article
Spinopelvic balance
Spinopelvic balance is an important concept in adult spinal deformities. There are numerous ways of assessing spinopelvic balance, using various bony landmarks and angles to evaluate whether or not a normal distribution of weight and stresses is present through the axial skeleton, some incorpora...
Article
C1-C2 false localizing sign (spine)
C1-C2 false localizing sign, sometimes referred to merely as C1-C2 sign, is seen on spinal imaging and can lead to the mislocalization of a CSF leak in individuals with intracranial hypotension.
There are numerous reports of fluid at this location that have been interpreted as the actual site ...
Article
Heterozygous HTRA1-related cerebral small vessel disease
Heterozygous HTRA1-related cerebral small vessel disease, also known as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy type 2 (CADASIL2), is a very rare monogenic cerebral small vessel disease.
Heterozygous HTRA1-related cerebral small vessel disease ...
Article
Hypomyelination with brainstem and spinal cord involvement and leg spasticity
Hypomyelination with brainstem and spinal cord involvement and leg spasticity (HBSL) is a very rare inherited autosomal recessive leukodystrophy characterized mainly by progressive early-onset lower limb-predominant spasticity.
Epidemiology
HBSL is extremely rare, although the exact incidence ...
Article
Bagel sign (Behçet disease)
The bagel sign is a radiological sign appreciated on MRI spine that is described in patients with neuro-Behçet disease-associated myelitis.
The sign describes the involvement of the spinal cord as seen on axial T2 sequences in patients with myelitis, whereby there is a round hyperintense lesion...
Article
Heterogeneous bone marrow signal
Heterogeneous bone marrow signal is a common but challenging MRI finding. It is usually an incidental finding but in a small minority can represent a serious underlying condition such as malignancy. It is most commonly described in the lumbar spine 1-3.
Terminology
No uniform term is used in t...
Article
Fluoroscopic myelography
Fluoroscopic myelography is a technique that allows the visualization of the theca by the introduction of contrast medium into the CSF. This is usually accomplished by a lumbar puncture, or less commonly a suboccipital puncture.
The patient can then be tilted and rotated to cause the contrast, ...
Article
Prebasioccipital arch
The prebasioccipital arch is a rare anatomical variant of the occipital bone that is part of the spectrum of occipital vertebrae 1.
Epidemiology
The prebasioccipital arch is a very rare variant; one study reported a prevalence of 0.025% 2.
Clinical presentation
The prebasioccipital arch is a...
Article
Basilar process
The basilar process, also known as the mammillar or papillar process, is a rare anatomical variant of the occipital bone that is part of the spectrum of occipital vertebrae 1.
Epidemiology
The basilar process is a rare variant, with a reported prevalence of 4% 2.
Clinical presentation
A basi...
Article
Dry tap (lumbar puncture)
A dry tap refers to a lumbar puncture where cerebrospinal fluid (CSF) cannot be obtained despite the needle tip being in the thecal sac 1. Dry taps may be associated with needle misplacement or blockage, dehydration, low CSF pressure, severe spinal canal stenosis (including epidural lipomatosis)...
Article
Post-dural puncture headache
Post-dural puncture headache, previously known as post-lumbar puncture headache 4, is a common complication after lumbar puncture (LP), which is often performed for cerebrospinal fluid (CSF) sampling, spinal anesthesia, myelography, etc.
Epidemiology
Post-dural puncture headaches occur after ~...
Article
H sign (spinal cord)
The H sign is a radiological sign appreciated on MRI spine that is classically described in patients with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD).
The sign describes the involvement of spinal cord grey matter as seen on axial T2 sequences in patients with myelit...
Article
Acrodysotosis
Acrodysotosis, also known as Arkless-Graham syndrome, Maroteaux-Malamut syndrome or acrodysplasia, is a rare genetic disorder affecting bone growth.
Epidemiology
The true incidence is not known. There is no known gender predilection. The condition is often detected in early childhood.
Clinica...
Article
Trident sign (neurosarcoidosis)
The trident sign is a radiological (MRI) sign described in spinal cord neurosarcoidosis.
The sign is formed by the axial appearance of a longitudinally extensive transverse myelitis due to spinal cord neurosarcoidosis, whereby on a T1 post-contrast (gadolinium) MRI sequence, there is central ca...
Article
Pancake sign
The pancake sign represents flat, tranverse gadolinium enhancement at the midpoint of a hyperintense, spindle-shaped T2 signal and is seen on sagittal and axial MR imaging 1. The axial corollary is formed by circumferential enhancement with sparing the spinal gray matter 2. Of note, the enhancem...
Article
Lumbar canal stenosis
Lumbar canal stenosis is a general term that refers to the pathological narrowing of the spinal canal, nerve root canals and/or the intervertebral foramina in the lumbar spine 1-4,6,7,9,10.
Epidemiology
Lumbar canal stenosis is common, especially among individuals over 60 years old, and its pr...
Article
Laminoplasty
Laminoplasty, also known as osteoplastic reconstruction of the lamina, is a surgical procedure that involves the replacement of the lamina of the vertebral body following a laminectomy procedure in an attempt to provide better post-operative stabilization.
Indications
spinal stenosis
compress...
Article
Muhle staging system of cervical canal stenosis
The Muhle staging system is a classification system used to evaluate the severity of cervical canal stenosis.
The system was developed based on a study conducted by Muhle et al. who used kinematic MRI to assess the dynamic changes of the cervical spine in patients at different stages of degener...
Article
CT myelography
CT myelography (CTM) is a myelography technique used mainly to assess for potential spinal canal stenosis when MRI is contraindicated or when dynamic imaging is required.
History
CT myelography was first performed in 1976 2 and became the gold standard for imaging the spinal canal and cord unt...
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