Functional MRI scans – the future of MR imaging:
The latest in imaging has arrived, in the form of Functional Magnetic Resonance Imaging or F- MRI scans.
Imaging remained largely a means to study anatomical lesions of the body, such as tumours, infections etc. But now, F- MRI is set to change all that. F- MRI is a technique that actually maps hemodynamic changes (read blood flow changes) in response to
neural stimuli or neural activity, in the brain and spinal cord. This is based on the fact that that there are changes in blood flow patterns in regions of the brain that are active; for example moving the fingers would produce more blood flow and oxygenation in the region of the brain called the motor cortex. The MR signals of the blood vary according to the degree of oxygenation. This fact is made use of to color code the brain’s activity. F- MRI can thus non-invasively detect human brain tissue activity, without the fear of radiation.
I had the chance to see a slide show, where an F- MRI scan of a patient with anxiety disorder, was displayed. Multiple areas (colored red) were seen along both cerebral hemispheres. After making the same patient relax, listening to gentle music, a repeat F MRI scan showed a near normal appearance. Thus, the role of this technique, in neurology and psychiatry is obvious. A more controversial use of the technique in comatose patients, found that in some such cases, in so called minimally conscious states,
the brain showed responses to speech and external stimuli, similar to those in normal persons. This raises many questions, indeed a Pandora’s box of legal and ethical issues regarding the conventional definition of death.