Neurological Imaging

x-rays / radiographs

assess hard bony tissues which can help determine if there is a fracture by looking at the skull and spine

how do x-rays work

external radiation is used to produce images of the body by passing through soft tissues more (black on film) and dense bone or tumors less (white appearance on film)

CT scans work by

taking a series of x-ray images from various angles. Computer technology creates cross sectional images.

Ct scans can diagnose

fractures, tumors, infections, blood clots, and hemorrhages

CT scan advantages

more detailed than x-ray, safe, cost effective, high availability, quick

CT scan disadvantage

more radiation exposure than x-ray, potential reaction to contrast dye.

how does MRI work

by using magnetic fields and computer generated radio waves to take detailed images of organs and tissues.

MRI assess for

tumors, abscesses, infarcts, demyelinating diseases, and soft tissue imaging.

MRI advantages

no radiation exposure and improved resolution of images

MRI disadvantages

claustrophobic and loud, susceptible to movement artifact, contraindicated with pacemakers, require special housing, takes longer, more expensive, metal in the body.

FRMI

measures brain activity by detecting changes associated with blood flow during a task. Brain maps active areas of the brain.

angiography

provides intra and extra cranial circulation via x-ray imaging to assess for blood flow restrictions to the brain. uses a dye injection and is performed via fluoroscopy machine.

agniography risk

embolism and stroke, allergy to dye, vascular spasm

agnopgraphy diagnoses

aneurysms, vessel malformations, vessel dissections, angiitis

MRA is

magnetic resonance angiogram which uses MRI to assess blood flow which is less painful and invasive than traditional angiogram.

MRA risks

allergy to the dye, claustrophobia in MRI scanner, no metal, no pacemaker

PET scan

a noninvasive assessment of the function of organs by using radioactive tracer to show activity. It can catch pathology before images. Good for metabolic problems such as cancer and brain disorders.

ultrasound works by

providing imaging of the brain via sound waves. It is most commonly performed in infants

ultrasound in the brain can help detect

tumors, bleeding, and hydrocephalus in infants. Stenosis of blood vessels in adults.

EEG

evaluates electrical activity in the brain by tracking and recording brain wave patterns.

EEG with electrodes attached to the scalp can help diagnose

seizures of epilepsy, brain tumors, stroke, sleep disorders, and brain damage after a head injury.

evoked potnetials measure

the time it takes for nerves to respond to stimulation that may be visual, auditory, or somatosensory.

evoked potentials can help detect

demyelinating disorders, tumors, MS, or coma

lumbar puncture

an invasive outpatient procedure to remove CSF from the subarachnoid space by inserting a needle between two lumbar vertebrae.

what are the purposes of lumbar punctures

obtain pressure measurements, CSF sample, and mobility assessment

normal intracranial pressures in adults

100-180 mm H20

increased intracranial pressure in adults

>200 mm H20

hypotensive intracranial pressure in adults

normal intracranial pressure in children

30-60 mm H20

lumbar puncture risks

headaches, back pain, bleeding, brainstem herniation

EMG

assess health of muscles and their motor neurons.

EMG can help detect

muscle dysfunction, nerve dysfunction, or problems with muscle to nerve signal transmition

when are EMGs ordered

when a patient reports weakness, tingling or numbness, muscle pain or cramps

EMG can help diagnose

ALS, muscular dystrophies, neuropathies