Heart-health risks show up in brain MRI as early predictors of Alzheimer’s

Drinking, smoking and chronic overeating are among the risky behaviors known to hurt not only the heart but also the brain. A new study combining cognitive testing with 3D brain MRI provides a clearer picture of this gradual undoing of the mind in process.

The work may help both cardio and neuro docs point patients toward warding off, or at least slowing the advance of, dementia and Alzheimer’s disease.

Led by Rajiv N. Srinivasa, MD, a radiologist with the University of Texas Southwestern Medical Center in Dallas, study authors were able to associate particular cardiovascular risk factors with loss of gray matter in particular brain regions before the onset of symptoms.

For example, among other region-specific insights into how to identify actionable early predictors of cognitive impairment, they found that smoking and obesity correlated with size reductions in the posterior cingulate cortex. This is the part of the brain known to handle memory retrieval, emotional functioning and social behavior.

The study, just released in Radiology, analyzed results from 1,629 participants in the Dallas Heart Study.

After evaluating clinical and lab data from initial baseline visits, the researchers looked at follow-up data gleaned seven years later in brain MRI scans and cognitive tests.

About half the study group (805 individuals) comprised people under 50 years old; the other group (824) fell in on the upper side of that divide.  

According to the study report, one key clinical takeaway was the finding that associations of brain volumes with risk factors and cognitive impairments were observed even in participants younger than 50.

“This may corroborate the importance of clinical strategies to preserve brain health beginning in midlife,” the authors write.

‘Ideal’ MRI

In an email exchange with Health Imaging, Srinivasa described the imaging component of the study.

Neither PET nor CT was considered for the study, as the original design of the Dallas Heart Study used exclusively MRI for brain imaging. That was a good thing, Srinivasa said.

“MRI was the ideal choice for this study as it allowed for a quantitative approach by obtaining 3D data for use in volumetric analysis,” he explained. “Further, it allowed for the automated parcellation of the brain in to distinct anatomic regions to detect regional differences in susceptibility to cardiovascular risk factors.”

All images were obtained without contrast on a 3T MR scanner utilizing a T1-weighted gradient echo sequence called 3D-MPRAGE (Magnetization-Prepared Rapid Acquisition with Gradient Echo), Srinivasa said.

The images were reviewed by a board-certified neuroradiologist prior to volumetric analysis, he added, and individuals with structural defects, imaging evidence of stroke, hydrocephalus or with any acquisition errors such as metallic susceptibility artifact, motion or significant noise were excluded.

Actionable patient info ahead

How close is radiology to using these kinds of imaging exams to help clinicians provide patients with information they can use in their fight against the twin foes of lifestyle-related cardiovascular disease and debilitating cognitive decline?

“The goal of utilizing MRI in the clinical setting would be to follow individuals over years and detect subtle changes in regional brain volume,” responded Srinivasa. “Subtle changes in volume may be detectable early in the course of disease, and this would allow us one method for quantifying the efficacy of any interventions.

“There are already vendors who have created such software for quantitative analysis, and they are beginning to be utilized at our institution and others.

“Further longitudinal studies are necessary to determine the impact that lifestyle modifications have on brain volumes,” said Srinivasa, “and the increased utilization of quantitative brain volume analysis software will help to answer these questions.”