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functional magnetic resonance imaging (fMRI)
Indications:
- may be useful as objective measure of pain [1]
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:
1) alternating on-off block design (i.e. talk, rest)
2) event-related fMRI
Advantages:
1) potential for high temporal & spatial resolution
2) no radioactive agents
3) can be repeated multiple times per session (no contrast agent given)
Disadvantages:
1) extremely sensitive to head movements
2) awkward environment
3) cannot perform receptor-ligand studies
4) orbitofrontal & medial temporal lobes vulnerable to air- tissue artifacts
Notes:
- BOLD-fMRI (blood oxygen-dependent level)
General
magnetic resonance imaging (MRI, diffusion-weighted MRI)
References
- Wager TD et al
An fMRI-Based Neurologic Signature of Physical Pain.
N Engl J Med 2013; 368:1388-1397April 11, 2013
PMID: 23574118d
http://www.nejm.org/doi/full/10.1056/NEJMoa1204471
- Jaillard A and Ropper AH.
Pain, heat, and emotion with functional MRI.
N Engl J Med 2013 Apr 11; 368:1447
PMID: 23574124
http://www.nejm.org/doi/full/10.1056/NEJMe1213074