Proton MR spectroscopic imaging of basal ganglia and thalamus in neurofibromatosis type 1: correlation with T2 hyperintensities.
BACKGROUND
Neurofibromatosis type 1 (NF1) is frequently associated with hyperintense lesions on T2-weighted images called "unidentified bright objects" (UBO). To better characterize the functional significance of UBO, we investigate the basal ganglia and thalamus using spectroscopic imaging in children with NF1 and compare the results to anomalies observed on T2-weighted images.


METHODS
Magnetic resonance (MR) data of 25 children with NF1 were analyzed. On the basis of T2-weighted images analysis, two groups were identified: one with normal MR imaging (UBO- group; n = 10) and one with UBO (UBO+ group; n = 15). Within the UBO+ group, a subpopulation of patients (n = 5) only had lesions of the basal ganglia. We analyzed herein seven regions of interest (ROIs) for each side: caudate nucleus, capsulo-lenticular region, lateral and posterior thalamus, thalamus (lateral and posterior voxels combined), putamen, and striatum. For each ROI, a spectrum of the metabolites and their ratio was obtained.


RESULTS
Patients with abnormalities on T2-weighted images had significantly lower NAA/Cr, NAA/Cho, and NAA/mI ratios in the lateral right thalamus compared with patients with normal T2. These abnormal spectroscopic findings were not observed in capsulo-lenticular regions that had UBO but in the thalamus region that was devoid of UBO.


CONCLUSIONS
Multivoxel spectroscopic imaging using short-time echo showed spectroscopic abnormalities in the right thalamus of NF1 patients harboring UBO, which were mainly located in the basal ganglia. This finding could reflect the anatomical and functional interactions of these regions.
Department of Neuroradiology, CHRU & Tours University, Tours 37000, France.
Charlotte
C
Barbier
Camille
C
Chabernaud
Laurent
L
Barantin
Philippe
P
Bertrand
Catherine
C
Sembely
Dominique
D
Sirinelli
Pierre
P
Castelnau
Jean-Philippe
JP
Cottier
D000293:Adolescent; D001479:Basal Ganglia / Q000378:metabolism* / Q000473:pathology*; D015415:Biomarkers / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D009456:Neurofibromatosis 1 / Q000378:metabolism* / Q000473:pathology*; D011522:Protons; D013223:Statistics as Topic; D013788:Thalamus / Q000378:metabolism* / Q000473:pathology*
D015415:Biomarkers; D011522:Protons