Each patient received intravenous infusions of saline in an initial session, and physostigmine in a second session 48 hours later. Physostigmine is a short-acting cholinesterase inhibitor, used to test the functional integrity of the cholinergic system, a neurotransmitter system involved in the regulation of memory and learning.
"ASL scanning after giving this medication is particularly well suited to diagnosing Gulf War illness, because it picks up brain abnormalities too subtle for regular MRI to detect," said co-author Richard W. Briggs, Ph.D., professor of radiology at UT Southwestern. "This allows us to make the diagnosis in a single two-hour session without the need for exposure to ionizing radiation."
The findings replicated the results of the initial SPECT study of largely the same group of veterans. The results showed that abnormal hippocampal blood flow persisted and may have progressed 11 years after initial testing and nearly 20 years after the Gulf War, suggesting chronic alteration of hippocampal blood flow.
Physostigmine significantly decreased rCBF in control participants and veterans with syndrome 1, but significantly increased rCBF in the right hippocampus of veterans with syndrome 2 in the original study. The abnormal increase in rCBF was now found to have progressed to the left hippocampus with syndrome 2 and to both hippocampi of the veterans with syndrome 3.
"Having an objective diagnostic test allows researchers to identify ill veterans for future clinical trials to test possible treatments," Dr. Haley said. "It is also critical for ongoing genomic studies to see why some people are affected by chemical exposures, and why others are not."
|Contact: Linda Brooks|
Radiological Society of North America