Brain Lesions After Stroke May Predict Future Episodes

different xray images of the brainIschemic stroke patients who have recurrent asymptomatic brain lesions within
three months of their initial stroke are at increased risk for subsequent
strokes, says a U.S. study in the December issue of the journal Archives of
Neurology
.

An ischemic stroke
occurs as a result of inadequate blood flow to the brain.

Previous research
found that asymptomatic (silent) brain lesions — changes in brain tissue that
occur in areas where blood flow is blocked or reduced — occur more frequently
than symptomatic lesions up to three months after a stroke, according to
background information in the article.

The authors of this
current study investigated whether silent brain lesions detected by MRI scans
could help predict stroke patients’ risk for subsequent
strokes.

Researchers at the
National Institute of Neurological Disorders and Stroke studied 120 ischemic
stroke patients. Each patient had an MRI brain scan within 24 hours of the
stroke and five days after the stroke. Of those patients, 68 had a follow-up MRI
after 30 days or up to 90 days after the stroke.

The study found that
patients who had silent ischemic lesions on the 30- or 90-day MRI were about 6.5
times more likely than other patients to suffer a subsequent ischemic stroke.
Patients with silent lesions on any of the MRI scans (24 hours, five days, 30
days, or 90 days) had an increased risk of death from vascular causes, recurrent
ischemic stroke or transient ischemic attack.

“It is a matter of circumstance, rather than tissue pathological
features, that determines whether cerebral ischemia is symptomatic or silent,”
the study authors wrote. “Clinical symptoms depend on the size, location and
number of new lesions. Thus, we assume that the pathological process that causes
silent lesion recurrence on MRI is the same as the process that causes clinical
recurrent strokes. Magnetic resonance imaging may depict pathological changes
before the development of clinical stroke symptoms.”

Childhood Cancer Survivors at Risk for Stroke

A smiling doctor having a conversation with a little girlSurvivors of childhood leukemia and brain tumors have an increased risk of
stroke later in life, a study shows. This is particularly true for children
treated with radiation therapy to the head at doses greater than 30 Gy.

These findings
justify the continuation of efforts to reduce radiation doses in children being
treated for leukemia or brain tumors when possible, conclude Dr. Daniel C.
Bowers from The University of Texas Southwestern Medical School, Dallas, and
colleagues.

The study, which was
published in the Journal of Clinical Oncology, included 4,828 leukemia survivors
and 1,871 brain tumor survivors. These subjects, who were younger than 21 years
when they were diagnosed between 1970 and 1986, were compared with a group of
3,846 of their siblings.

This is the first
study, the authors point out, to look at the risk of late-occurring stroke among
childhood leukemia survivors and is “by far the largest study” to examine the
risk of stroke in childhood brain tumor survivors.

According to the
team, 37 leukemia survivors and 63 brain tumor survivors experienced a stroke 5
or more years after diagnosis.

Compared with the
sibling group, the leukemia survivors had 6.4-fold greater risk of stroke, and
the risk for brain tumor survivors was increased by 29.0-fold.

In children who
received radiotherapy at an average dose of 30 Gy or greater had a stroke risk
that increased in a dose-dependent fashion.

“Importantly,
although the risk of stroke among leukemia and brain tumor survivors is
significantly increased, it is still a relatively uncommon event during the
first two decades after the cancer diagnosis,” the authors note.

The rate of
late-occurring stroke for leukemia survivors was 57.9 per 100,000 per year, and
267.6 per 100,000 per year for brain tumor survivors.

“How this risk will change as these cancer survivors age is not known,”
the study team points out.