functional magnetic resonance imaging (fMRI)

Indications

• may be useful as objective measure of pain

Advantages

• potential for high temporal & spatial resolution
• no radioactive agents
• can be repeated multiple times per session (no contrast agent given)

Disadvantages

• extremely sensitive to head movements
• awkward environment
• cannot perform receptor-ligand studies
• orbitofrontal & medial temporal lobes vulnerable to air- tissue artifacts

Procedure

• images are acquired to take advantage of the fact that oxy- hemoglobin (Hgb-O2) is paramagnetic, whereas deoxy-hemoglobin is not
• no contrast agent is needed

fMRI paradigms:

• alternating on-off block design (i.e. talk, rest)
• event-related fMRI

Notes

• BOLD-fMRI (blood oxygen-dependent level)

More general terms

• magnetic resonance imaging (MRI, diffusion-weighted MRI)