A special type of magnetic resonance imaging (MRI) can depict changes in blood volume in the brain that often precede cancerous transformation of brain tumors, according to a new study published in the April issue of the journal Radiology.
“We found that increases in blood volume within the tumor measured noninvasively by perfusion MRI precede other markers of malignant transformation by a year or more,” said study co-author Adam Waldman, Ph.D., M.R.C.P., F.R.C.R., consultant neuroradiologist and imaging research director at Imperial College NHS Trust and honorary senior lecturer at Imperial College and University College, London.
Low-grade gliomas are primary brain tumors that grow slowly over several years. Eventually, almost all low-grade gliomas progress to high-grade gliomas, which carry a poor prognosis.
“Patients with low-grade gliomas are often young and may remain clinically well for many years but, at an unpredictable time their tumor will transform to an aggressively high-grade glioma,” Dr. Waldman said.
For the study, the researchers performed perfusion MRI on 13 patients with low-grade gliomas to determine whether relative cerebral blood volume (rCBV) changes are an indicator of future malignant transformation.
Brain tumors can bring about the formation of new blood vessels, a process known as angiogenesis. These vessels are abnormal and lead to changes in blood volume and flow. Using perfusion MRI, radiologists can detect these changes well before they become apparent on contrast-enhanced MR images.