MR Spectroscopy May Help Avoid Invasive Procedures for Recurrent Brain Lesions

A clinical decision model that uses magnetic resonance (MR) spectroscopy to help physicians differentiate between recurrent tumors and changes in the brain tissue due to radiation treatments, may help patients avoid invasive procedures and treatments.

A study performed at the University of Michigan Health System (Ann Arbor, MI, USA) included 33 patients who had undergone radiation treatment for brain tumors and had MRI examinations that revealed new lesions (either a recurrent tumor or radiation changes). Patients then underwent MR spectroscopy and ratios of three metabolites, choline (Cho), creatine (Cr), and n-acetylaspartate (NAA) were calculated. A receiver operator characteristic (ROC) curve and prediction model was then created, which determined the post-test probability of a patient having a recurrent tumor. For the study, the final number of patients with recurrent tumors was 20 and those with post-radiation change were 13.

"MR spectroscopy looks inside each area of the brain and determines concentrations of metabolites that are there,” said Ethan Smith, M.D., lead author of the study, which was published in the February 2007 issue of the American Journal of Roentgenology (AJR). "Choline, creatine, and NAA are the three metabolites that are most commonly looked at. They are found inside the cells of the brain and the ratios between each change depending on if the cells are malignant or benign. With further work, this technique could save some patients from unnecessary brain biopsies,” said Dr. Smith.

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