Silent brain damage caused by reduced blood flow, known as ischemic injury, appears to be much more common in cerebral small vessel disease than previously thought. Researchers from Radboudumc and collaborating centers found that these hidden lesions are frequently visible on advanced MRI scans, even in patients who have no clear stroke symptoms.
Cerebral small vessel diseases affect the brain’s smallest blood vessels and are a major cause of stroke and cognitive decline. Yet it is often difficult to measure how active these diseases are before symptoms become noticeable. The new findings suggest that ongoing, silent brain injury may be an important feature of these conditions and could help doctors monitor disease activity more effectively.
Studying two different small vessel diseases
The researchers focused on small recent injuries to brain tissue that can be detected with diffusion-weighted imaging, or DWI, a specialized MRI technique. These lesions are usually discovered by chance, and patients are often unaware they have occurred. Until now, it was unclear how often these lesions appear and what they mean for disease progression.
The team studied MRI data from two prospective research cohorts in the Netherlands and Germany. One group included patients with probable cerebral amyloid angiopathy, or CAA, a disease in which amyloid protein builds up in the walls of blood vessels in the brain. CAA mainly affects older adults and is best known for causing bleeding in the brain. The second group included patients with CADASIL, a rare inherited form of small vessel disease.
Using high-resolution MRI scans, the researchers examined how often these silent injuries occurred, where they appeared in the brain, and whether they were linked to other signs of disease severity.
Frequent lesions with distinct patterns
The results showed clear differences between the two diseases. More than half of the patients with CAA had silent ischemic lesions, compared with about one in five patients with CADASIL. The location of the lesions also differed strongly. In CAA, most were found in the cerebral cortex, the outer layer of the brain. In CADASIL, they were found almost entirely in deeper brain regions.
Patients with these silent lesions also had higher levels of neurofilament light chain, or NfL, a biomarker that increases when nerve cells are damaged. In patients with CADASIL, the lesions were also linked to other MRI signs of more advanced disease.
The findings suggest that silent ischemic brain injury is a common and previously underrecognized feature of cerebral small vessel disease. These lesions may offer a useful way to track active disease and to better understand how these conditions progress over time.
Future studies will investigate whether silent brain lesions can predict long-term outcomes such as stroke, cognitive decline, or response to treatment. If so, they could become an important biomarker for monitoring disease activity and evaluating new therapies in clinical trials.
About the publication
The study was published in Neurology as: Incidental DWI-Positive Lesions in 2 Cohorts of CAA and CADASIL: Prevalence, Distribution, and Associations With Clinical Variables, by ter Telgte A, de Kort AM, Dewenter A, Kopczak A, Gesierich B, Kuiperij HB, Klijn CJM, Duering M, Verbeek MM, and Schreuder FHBM.
