Imaging of Head/Neck Flashcards
This type of imaging is produced by sudden deceleration of electrons hitting anode.
X-Ray (Radiograph)
In an X-ray, tissues will differentially absorb radiation of…
Gas
Fat
Water
Mineral
What can X-rays indicate?
Trauma (fractures)
Degenerative Diseases (i.e., RA)
Post-Operative
What are the types of X-Ray?
PA
AP
Lateral
What are adverse effects of X-Rays?
Radiation
What are contraindications of X-Rays?
Pregnancy
This type of X-Ray is most accurate in determining heart size when a person can stand.
PA
***Can use AP when a patient cannot stand
This is type of imaging is when continuous X-Ray radiation passes through the body onto a fluorescent screen creating a moving X-Ray image.
Fluoroscopy/Angiography
What are fluoroscopy/angiography indications?
Swallow study
Interventional radiology
Arthrography
Cardiac Catheterization
Angiography involves injection of contrast into vasculature, such as…
Barium
Iodine
What are adverse effects of fluoroscopy/angiography?
Allergic reaction (to contrast)
What are contraindications of fluoroscopy/angiography?
Acute kidney injury
Known allergy
Certain medications (Metformin)
Pregnancy
This is a form of fluoroscopy intended to evaluate peripheral vasculature.
Angiography
What can angiography indicate?
Aneurysm Vascular malformations Fistulae Stenosis Thrombosis Dissection Stenting Thrombolysis
What are the pros of angiography?
Fast
Diagnostic and therapeutic
What are the cons of angiography?
Invasive
Contrast
Radiation
This is a type of fluoroscopy that uses an intrathecal injection of contrast.
Myelography
What can myelography indicate?
Spinal stenosis
Nerve root compression
CSF leak
What are the pros of myelography?
Defines subarachnoid space
Identifies spinal block
What are cons of myelography?
Invasive
CSF Leak, Headache
Radiation
Contrast
What are contraindications of myelography?
Pregnancy
Kidney damage
Allergies to contrast
This type of imaging is a series of X-rays scanned axially. The X-rays are digitally re-sliced in any plane.
Computer Tomography (CT)
In CT, radiodensity is measured in…
Hounsfield Units (HU)
How many HU is water?
0
In CT, all densities are compared to water (0 HU). Hyperdense things appear (WHITE/BLACK), while hypodense things appear (WHITE/BLACK).
White
Black
***Bone would be hyperdense (+1000), and air would be hypodense (-1000)
In CT, how are scans read?
As if looking at the patient from the feet
What can CT be used for?
Skull, skull base and vertebrae Ventricles Intracranial masses, mass effect Hemorrhage, ischemia Calcification
What are the pros of CT?
Fast
Relatively inexpensive
Good at detecting large pathology
What are the cons of CT?
Less detail than MRI
Radiation exposure
Low sensitivity in posterior fossa
When should contrast be used in CT?
Neoplasm Infection Vascular disease Inflammatory disease More than 3 hours after onset of symptoms
When should non-contrast CT be used?
Trauma Hemorrhage Hydrocephalus Dementia Epilepsy Within 3 horus of symptoms
T/F. Non-contrast CT is used in patients with head/spine trauma and acute stroke. It is the fastest test to use in emergent situations to provide an appropriate level of detail.
True
This usually keeps IV contrast out of the brain (gray and white matter). Enhancement of brain parenchyma indicates the absence of this or its pathology.
Blood Brain Barrier
What structures will enhance with IV contrast outside of the Blood Brain Barrier?
Cerebral blood vessels Meninges (Dura, Arachnoid, Pia Mater) Pineal Gland Pituitary Gland Choroid Plexus
This creates a rapid IV contrast bolus and is scanned during the arterial phase. It can be digitally reconstructed into 2D and 3D images.
CT Angiography
What can CT angiography be used for?
Atherosclerosis
Dissection
Aneurysm
Trauma
What are pros of CT angiography?
Non-invasive
Examine vessels from origin
What are cons of CT angiography?
Contrast
Radiation
Lower resolution
For this type of imaging the patient lies in a large magnet which aligns all the protons in the body. Radio waves are then passed through the patient and the returning signals are converted into an image.
Magnetic Resonance Imaging (MRI)
MRI is measured by its radiodensity. Hyperintense things appear (BLACK/WHITE) while hypointense things appear (BLACK/WHITE).
White
Black
What can MRIs be used for?
Further evaluation of CT findings
Tumors
Infections
Joint Imaging (i.e., TMJ)
What are the pros of MRI?
High level of detail
Safe to use in pregnancy
Vessel imaging can be obtained without use of contrast
What are the cons of MRI?
Time consuming
Contraindications (metal/implantable devices)
Expensive
Claustrophobia
This type of MRI is when CSF is dark (hypointense) and white matter is bright (hyperintense). It is good for imaging normal anatomy.
T1 Weighted MRI
This type of MRI is when CSF is bright (hyperintense) and white matter is dark (hypointense). It is good for visualizing pathology.
T2 Weighted MRI
This type of MRI is an inversion recovery set to null fluids.
FLAIR (Fluid Attenuated Inversion Recovery)
This type of MRI removes CSF from T2 MRI (CSF is bright in this type). Enhances fluid with high protein content, such as edema/abscess.
T2 FLAIR
This a noninvasive imaging technique that has a transducer that emits ultrasound waves into the body. The transducer then function as a receiver that records the energy.
Ultrasound
What are uses for ultrasound?
Evaluation of Carotid arteries
Placement of central lines
What pros of using ultrasound?
Non-invasive
Cheap
No radiation
What cons of using ultrasound?
Learning curve
Review the practice cases (slides 22-33)
Review 10 minutes!
