MR spectroscopy shows promise in evaluating pediatric brain tumors

CONTEXT: Neuroradiology fellow Dr. Roula Hourani at Johns Hopkins University researched the ability of proton MR spectroscopy (MRS) to differentiate between benign brain neoplasia and tumors in children. Potentially, such a non-invasive diagnostic approach would most benefit children with non-neoplastic lesions and less accessible tumors that could be treated by radio- or chemotherapy.

RESULTS: MRI and high-resolution multislice proton MRS (three to four 15-mm slices separated by 2.5 mm) were performed on 36 children with primary brain lesions on a 1.5T scanner using a standard birdcage head coil. Resolution of 0.8-mL voxel size was the same in all experiments. MRS provided data on choline (Cho) and creatine (Cr), revealing that tumors and non-neoplastic lesions could be distinguished by differences in the Cho/Cr ratio, with tumors having a higher Cho/Cr ratio.

IMAGE: Comparison of proton MR spectra of a benign thalamic lesion (A: acute disseminated encephalomyelitis, nine-year-old female) and a tumor (B: pilocytic astrocytoma, 12-year-old male). A higher Cho/Cr ratio was detected in the tumor (Cho/Cr = 2.03) than in the benign lesion (Cho/Cr = 0.80).

IMPLICATIONS: This is the first study to apply multislice MRS sequences to differentiate nonneoplastic lesions from tumors in children. The study provides preliminary data that proton MRS can help evaluate pediatric brain lesions. The approach holds the most promise in identifying inaccessible and benign lesions (avoiding the need for biopsy). The next step in this work is a prospective study combining spectroscopy with other MRI techniques, such as perfusion, according to researcher Alena Horska, Ph.D, an assistant professor of radiology at Johns Hopkins.