Functional MRI: Emerging Uses for Neurological Diseases – Part 2

Despite the fact that functional MRI was discovered in the early 90′s, scientific research related to its clinical applications is still at an early stage. The first paper on the use of functional MRI (fMRI) in Alzheimer’s disease came out as late as 1999. Today, fMRI is being intensively studied in a number of other clinical areas like dyslexia, epilepsy, mood and anxiety disorders, pain management, rehabilitation after stroke and schizophrenia. Though the application of fMRI in routine neurological practice is still some years away, already our understanding of these disorders and knowledge about mapping progression and treatment effects with fMRI is rapidly progressing.

Alcohol and substance abuse, for example is another developing area. Studying the effect of pharmacological substances on MRI blood flow patterns is spearheaded by the rapidly growing area of pharmacological MRI (phMRI). Updated models of craving and addiction incorporating fMRI criteria demonstrate that over the course of addiction, as it becomes chronic, an orderly change in brain blood flow patterns sets in, as more and more areas get involved.

Pre-surgical planning with functional neuroimaging has been undergoing evaluation over the past few years, particularly in cases involving resections of brain tumors and arterio-venous malformations, as well as in surgery for epilepsy. One important problem with these procedures is the collateral damage inflicted by surgery on vitally important structures and tracts in the vicinity of the lesion. By a pre-operative fMRI evaluation, it is relatively easy to visualize what cognitive, motor or sensory functions are likely to be impaired following the resection, and counsel the patient accordingly. In addition a pre-operative ‘functional’ map might guide surgeons to limit the extent of damage by making them aware of the proximity of functionally important areas. One study found pre-surgical fMRI useful in 89% of tumor and 91% of epilepsy surgical patients.

The future for fMRI is bright. While the technology is still improving, there is a lot of research that needs to be done, along with statistical validation of brain maps from various sources. But it is already leading to a paradigm shift in our understanding of how the brain works in real-time, and perhaps for the first time, we have developed a visual probe in to our minds. As the logical next step, we are standing on the threshold of a new approach to the clinical practice of neurology and its allied behavioral sciences.

References

Ogawa, S. (1990). Brain Magnetic Resonance Imaging with Contrast Dependent on Blood Oxygenation. Proceedings of the National Academy of Sciences, 87(24), 9868-9872. DOI: 10.1073/pnas.87.24.9868

Small, S.A., Perera, G.M., DeLapaz, R., Mayeux, R., Stern, Y. (2001). Differential regional dysfunction of the hippocampal formation among elderly with memory decline and Alzheimer’s disease. Annals of Neurology, 45(4), 466-472. DOI: 10.1002/1531-8249(199904)45:4<466::AID-ANA8>3.0.CO;2-Q

PORRINO, L., SMITH, H., NADER, M., BEVERIDGE, T. (2007). The effects of cocaine: A shifting target over the course of addiction. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 31(8), 1593-1600. DOI: 10.1016/j.pnpbp.2007.08.040