The study led by Norbert Schuff, PhD, a Principle Investigator at the San Francisco VA Medical Center (SFVAMC), used arterial spin labelling to measure perfusion, or blood flow, in the areas of the brain affected by the two diseases. "Progression of frontotemporal dementia is usually faster than Alzheimer's, and the underlying pathology is different, so it is important to know the difference," said Schuff.
In arterial spin labelling, a technique invented by researchers at the University of Pennsylvania, protons in arterial blood are magnetically aligned in the opposite direction from the rest of the protons in blood and brain tissue. By measuring the intensity of the magnetic signal from these inversely polarised protons when they reach the brain, researchers can calculate the amount of blood flow, and thus neuron activity, in a particular section of the brain.
In the study, Schuff and his fellow researchers measured brain perfusion in 24 Alzheimer's patients, 21 FTD patients, and 25 control subjects without dementia. The subjects were 62 to 90 years old, with an average age of just under 63. They were studied using an MRI system with a magnetic field strength of 1.5 Tesla, a common system in clinics and hospitals in the United States.
The researchers successfully used arterial spin labelling to replicate PET and SPECT data on brain perfusion in all subjects. They also found that the perfusion data, added to structural information about the brain obtained with conventional MRI, significantly improved the classification of FTD from normal aging.
Thus, "we gained specificity and sensitivity," Schuff commented. The next step for future research, Schuff said, is to demonstrate that the perfusion abnormalities correlate with specific clinical symptoms.
MEDICA.de; Source: University of California - San Francisco