Resting Functional and Diffusion MRI Technologies Provide Clues on Dementia and Consciousness Disorders

New magnetic resonance imaging (MRI) advances have helped visualize the brain to a degree where neuroradiologists can now begin to see the mind at work.

Leading researchers recently discussed where these latest developments at the European Congress of Radiology (ECR), held March 2013 in Vienna (Austria). Recent advances with resting functional MRI (rfMRI) and diffusion MRI (dMRI) technology enable researchers to better clarify complex processes such as autism, dementia, and depression, and established these technologies increasingly to be key to the diagnosis of comas and chronic disorders of consciousness.

fMRI has been utilized for over 20 years to visualize alterations in brain activity by comparing a task versus a control task, and demonstrating and quantifying how much brain activity is involved in the process. The recent addition of rfMRI enables researchers to monitor networks that are randomly active and mine data what they call the default mode network.

They have already noticed that several networks work differently in autistic patients, noted Dr. Stefan Sunaert, professor of neuroradiology at Leuven University Hospital (Belgium) and chairman of the ECR session. “For instance, in autistic children with language impairment, the classical language network is disconnected from the cerebellum, which now becomes the focus of major structural and functional studies in autism,” he said.

Researchers are also speculating how rfMRI could help predict dementia and Alzheimer’s disease (AD). Presently, rfMRI cannot reveal if a patient will ever suffer from AD, but techniques will soon arise, he believes. “We hope to develop techniques within the next five to ten years to predict whether somebody aged 40 to 45 who complains about a slight impairment or memory deficit is going to develop dementia within 10 years or age normally,” said Dr. Sunaert, stressing that neuroscientists still need to find and learn precisely how the brain works to understand disease.

dMRI can visualize white matter architecture, i.e., major white matter tracts connecting the brain to the spine, and the connection between brain regions. Combined with rfMRI, it has become increasingly relevant in the differential diagnosis of patients with chronic disorders of consciousness.

In Belgium alone, as many as 150 patients with chronic disorders of consciousness are diagnosed yearly. In the European Union (EU), an estimated 100,000 patients suffer from one of these disorders, which include minimally conscious state, persistent vegetative state—now called unresponsive wakefulness syndrome—and locked-in syndrome.

The past 15 years have seen a major change in the scientific perception of comas, with key developments being made using electroencephalography (EEG), positron emission tomography (PET), and MRI. Clinicians are now able to validate that some patients who seem comatose are in reality conscious, but their ability to communicate with the outside world has been damaged, for instance, following a an anoxic or traumatic event.

In her presentation, Dr. Carol Di Perri, a neuroradiologist working at the Coma Science Group, at the department of neurology and Cyclotron Research Center, University Hospital of Liège (Belgium), clarified how locked-in syndrome patients are able to communicate through MRI technology, and show that they still hear, feel, and understand what is going on around them, a development which could dramatically improve their fate. She also focused on the intense ethical debate surrounding those questions.

Related Links:
Leuven University Hospital
University Hospital of Liège