week 2- Imaging

Question 1

what is the signal intensity of tissue in MRI based off of

Answer 1

Signal intensity of tissue depends on water content, ratio of free/bound water molecules, protein content, and blood flow.

Question 2

differentiate between T1/T2 and flair imaging

Answer 2

T1- best for anatomy and areas of contrast enhancement

• white matter is white
• grey matter is grey
• CSF is black

T2- best to ID fluid in CSF or IV discs. ID strokes, tumors, infections

• white matter is black
• grey matter is grey
• CSF is white

Flair- super T2, can better if the pathological processes from T2

• white matter is grey
• grey matter is lighter
• CSF is black

Question 3

differentiate between angiograms with CT and with MRI

Answer 3

CT you have to use contrast and it has a great deal of radiation exposure

MR you can do without contrast

Question 4

ID these structures of the brain

Answer 4

Question 5

what are the major cerebral vessels that branch from the internal carotid arteries

Answer 5

ACA- anterior cerebral

deep

MCA- middle cerebral

deep

PC - post communicating…?

Question 6

ID the major contraindications for MRI

Answer 6

•Contraindications

–electrically, magnetically, or mechanically activated implants, including cardiac pacemakers, insulin pumps, cochlear implants, neurostimulators, bone-growth stimulators, and implantable drug infusion pumps

–Patients with intracardia cpacing wires or Swan-Ganzcatheters are at risk for RF current–induced cardiac fibrillation and burns.

–Ferromagnetic implants, such as cerebral aneurysm clips, vascular clips, and skin staples, are at risk for movement and dislodgment, burns, and induced electrical currents.

–Bullets, shrapnel, and metallic fragments may move and cause additional injury or become projectiles in the magnetic field.

–Metal workers and patients with a history of penetrating eye injuries should be screened with radiographs of the orbits to detect intraocular metallic foreign bodies that may dislodge, tear the retina, and cause blindness.

SAFE:

–Non-ferromagnetic vascular clips, staples and orthopedic devices.

–Prosthetic heart valves with metal components and stainless steel Greenfield filters are considered safe because the in vivo forces affecting them are stronger than the deflecting forces of the electromagnetic field.

• Pregnancy

Question 7

Answer 7

Question 8

Answer 8

Question 9

Answer 9

Question 10

acute versus chronic stroke

Answer 10