New imaging technique reveals early brain damage caused by hypertension

A new study has demonstrated that an advanced form of imaging can show brain damage caused by high blood pressure before any clear symptoms of damage become visible.

Diffusion tensor imaging (DTI), also known as tractography, is an enhancement of the more widely used magnetic resonance imaging (MRI) and is not currently performed in routine medical practice.

The study is due to be presented at the American Heart Association's (AHA) 2015 High Blood Pressure Conference being held in Washington, D.C.

"We already have clear ways to explore the damage high blood pressure can cause to the kidneys, eyes, and heart," states lead author Daniela Carnevale, an assistant professor at Sapienza University of Rome in Italy. "We wanted to find a way to assess brain damage that could predict the development of dementia associated with vascular diseases."

High blood pressure, also referred to as hypertension, is a known risk factor for vascular cognitive impairment. It can be difficult, however, to identify changes in the brain at an early stage that are associated with the future development of dementia.

For the study, the researchers examined 15 participants receiving medication for moderate or severe high blood pressure and 15 participants with normal blood pressure. Each participant underwent brain imaging with MRI and DTI, as well as cognitive assessment.

Prof. Carnevale explained to Medical News Today the differences between MRI and DTI. "With classic MRI we can only have information of global structural integrity of white matter," she said. "Through [DTI], we can isolate specific tracts and evaluate not only their structure but also their functionality."

While the MRIs did not reveal brain abnormalities in any of the participants, DTI revealed that those who had high blood pressure also had damage to several different areas of the brain. Fibers that affect nonverbal functions, executive functioning, emotional regulation and attention tasks were all damaged in the brains of these participants.

A new way to detect early signs of asymptomatic brain damage

Cognitive assessment showed that the participants with high blood pressure also performed significantly worse in tests examining cognitive function and memory compared with those with normal blood pressure.

Prof. Carnevale concludes that the new imaging technique could be used to identify predictive signs of vascular cognitive impairment caused by high blood pressure accurately:

"DTI provides a way to evaluate presymptomatic brain damage in people with high blood pressure in order to identify possible therapies to help control brain damage and reduce the eventual development of dementia. It is generally accepted that not all available medications have the same impact on different kinds of organ damage."

"We suggest to clinicians to start considering the potential brain damage in the clinical approach to hypertensive patients," Prof. Carnevale told MNT.

Although the study demonstrates the benefits of DTI and that it is a completely noninvasive examination, Prof. Carnevale explained it could be difficult to implement more widely in health care, stating that "the most challenging aspect of this technique is data reconstruction and analysis, together with cognitive assessment and clinical evaluations."

Such an approach, she said, implies the need for a multidisciplinary team that includes clinicians, biologists, informatics engineers and radiologists.

The participants in the study who had high blood pressure were also found to have damage to their hearts and kidneys after undergoing additional imaging and laboratory tests. This finding illustrates the extent of the impact that high blood pressure can have on the body.

Recently, MNT reported on a study that identified high blood pressure as the greatest avoidable risk factor for death and disease among adults worldwide, ahead of smoking and high body mass index (BMI).

Written by James McIntosh