MRI scans using diffusion tensor imaging can predict Alzheimer's disease

MRI scans using diffusion tensor imaging (DTI) show potential for predicting if a patient will develop Alzheimer’s disease later in life, according to findings to be presented at RSNA 2018 in Chicago.

"Alzheimer's disease is the most common cause of dementia in the world and is expected to increase globally, and especially in the US, as the population gets older," lead author Cyrus A. Raji, MD, PhD, of the Mallinckrodt Institute of Radiology at Washington University School of Medicine in St. Louis, said in a prepared statement. "As we develop new drug therapies and study them in trials, we need to identify individuals who will benefit from these drugs earlier in the course of the disease." 

DTI is able to provide data on white mater integrity, including a patient's fractional anisotropy (FA), which measures how water molecules move along white matter tracts within the brain. When those tracts are "not well connected," Raji noted, it can result in cognitive issues.

Raji and colleagues performed brain DIT exams on 61 patients from the Alzheimer’s Disease Neuroimaging Initiative. Half of those patients developed Alzheimer's later in life, and DTI was able to identify "quantifiable differences" in those patients' brains. 

The researchers noted that patients who developed Alzheimer’s had a lower FA in comparison to those who did not develop the disease. This implies there is white matter damage in people who develop Alzheimer’s. The researchers also noticed “statistically significant reductions” in some frontal white matter tracts.

"DTI performed very well compared to other clinical measures,” Raji said in the same statement. "Using FA values and other associated global metrics of white matter integrity, we were able to achieve 89 percent accuracy in predicting who would go onto develop Alzheimer's disease. The Mini-mental State Examination and APOE4 gene testing have accuracy rates of about 70 – 71 percent."

Upon further investigation of the white matter tracts in 40 patients from the original cohort, the researchers found their screening method had a 95 percent accuracy rate.

RSNA 2018 takes place at McCormick Place in Chicago from Nov. 25-30, 2018.