Single-voxel Proton MR Spectroscopy of the Basal Ganglia in Patients with Neurofibromatosis Type 1

Sung, Nak Kwan; Kim, Jong Ki; Oh, Kyu Hyen; Lee, Young Hwan; Chung, Kuk Soo; Kim, Ok Dong; Lee, Dong Kuck; Hwang, Jin Bok

Abstract

PURPOSE: To demonstrate the proton MR spectroscopic characteristics of non-neoplastic focal basal ganglialesions with high signal intensity on long TR MR images in patients with neurofibromatosis type 1(NF-1), and tocompare them with those of normal-appearing basal ganglia in patients without focal lesions.
MATERIALS AND METHODS
Single-voxel proton MR spectroscopy was performed in six patients with NF-1 from two families(three with andthree without non-neoplastic focal brain lesions). All six individual spectra were obtained from basal gangliawith voxel sizes of about 1 x 1 x 1 cm, three from focal pallidal lesions in patients with focal lesions and threefrom normal-appearing basal ganglia in patients without focal lesions. Spectra were acquired using a 1.5T clinicalMR imager and stimulated echo acquisition mode sequence, with the following parameters: 30 ms of echo time, 13.7ms of mixing time, and 2560 ms of repetition time. Zero and first-order phase correction was performed.
RESULTS
N-acetyl aspartate(NAA)/creatine(Cr) ratios were similar between focal basal ganglia lesions and normal-appearingbasal ganglia, though the former showed slightly lower choline(Cho)/Cr ratios and slightly higher NAA/Cho ratiosthan the latter. Relatively enhanced resonances around 3.75 ppm, assigned as glutamate/glutamine, were observed inthe spectra of three focal lesions. Lipid resonances around slightly different positions were observed in all sixpatients, regardless of the presence or absence of focal lesions.
CONCLUSION
Slightly decreased Cho levels andrelatively enhanced glutamate/glutamine resonances are thought to characterize the focal basal ganglia lesions ofNF-1. Different mobile lipids appear to be present in the basal ganglia of NF-1 patients, regardless of thepresence of focal lesions.