Week 3 - MRI

Question 1

MRI Procedure

Answer 1

Does not use ionising radiation - uses the force of the magnet, the proton axes line up

Question 2

MRI T1

Answer 2

Anatomically detailed with high resolution. fat is bright, fluid and calcium are black

Question 3

MRI T2

Answer 3

fluid is bright, muscles are dark

Question 4

MRI STIR

Answer 4

Suitable for highlighting fluid (bone bruising, effusion

Question 5

MRI Intravenous gadolinium

Answer 5

Generally not needed on routine bases. May improve sensitivity for small abscesses or sinus tract

Question 6

MRI indications

Answer 6

• soft tissue pathology - infections, ligament damage, tendonitis, masses, cysts or tumours, MSK trauma
• bone pathology - tumours, bruising, stress and insufficiency fractures

Question 7

MRI contradictions

Answer 7

• metallic fragments in the eye
• pacemakers
• aneurysm clips
• orthopaedic and dental hardware
• patient too large
• claustrophobic
• cochlear implants
• spinal stimulators
• inserted pumps
• some artificial valves

Question 8

MRI advantages

Answer 8

• Non ionising radiation is used
• superficial soft tissue contrast
• can scan in any plane
• MRI systems can also image flowing blood in virtually any part of the body without an injection of contract

Question 9

MRI disadvantages

Answer 9

patients with metallic/surgical impants may be contradicted
- can not scan very large patients
- long and loud scans
- expensive

Question 10

Difference between CT and MRI

Answer 10

Both:
- post processing options
- multi planar imaging
- cross sectional detail

CT:
- accessible
- fast
- IV contrast
- Good for MSK
- Good for patients that cant have MRI

MRI:
- no radiation
- can use IV contrast
- good for soft tissue, MSK system
- Good for patients that cant have CT