London, March 25 (IANS) A special kind of magnetic resonance imaging (MRI) can register changes in the brain’s blood volume that often precede tumours, according to a new study. “Patients with low-grade gliomas or primary brain tumours are often young and may remain clinically well for many years, but unpredictably their tumour will transform into an aggressively high-grade glioma,” said Adam Waldman of University of London and co-author of the study.

Brain tumours can spur formation of new blood vessels. They 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.

Researchers performed perfusion MRI on 13 patients with low-grade gliomas, every six months, up to three years, to determine whether relative cerebral blood volume (rCBV) changes indicate malignant transformation. Seven patients progressed to malignant gliomas within the period.

These findings suggest that significant changes in rCBV represent an important marker of malignant change in gliomas, reflecting the earliest stages of transformation process.

Further, the data support the likelihood that the cellular processes underlying malignant transformation may occur 12 months or more before visible on contrast MRI.

“We have shown that perfusion MRI provides a non invasive means of assessing the risk of transformation in individual patients,” Waldman said.

These findings have been published in the April issue of Radiology.