Journal of the Louisiana State Medical Society
Figure 1: MR images. Axial FLAIR (a), axial T2W (b), and coronal T2 (c) demonstrate a mass in the superior cerebellar hemisphere on the right with characteristic striations. DWI (d) and ADC (e) reveal no evidence of diffusion restriction. Sagittal T1W post- administration of Gd-DTPA (f) revealed the striating mass with no significant enhancement.
was performed on the abnormal area in the right superior cerebellar hemisphere using both short and long echo times (TE) of 144 and 35 ms, respectively (Figure 2). 6 The lesion was compared with normal comparable tissue in the left hemisphere. 7 Within the lesion, there was maintenance of N-acetyl-aspartate (NAA), choline (Cho) and myo-inositol (MI), as well as maintenance of the creatine/choline ratio (Cr/Cho). Abnormal elevated lactate was demonstrated with both TE times and was most likely due to increased glucose metabolism. 8 DISCUSSION
lesions, allowing non-invasive assessment of the meta- bolic characteristics of abnormal tissue. Proton magnetic resonance spectroscopy ( 1 HMRS) is useful in analyzing the central nervous system (CNS), due to the high hydrogen concentration in brain tissue. 9 In MR spectroscopy, varying amounts of metabolite are displayed as peaks on a spectral graph. The greater the area under the curve, the larger the amount of metabolite is present in the sample. 10 In order to obtain this spectrum, free induction decay (FID) signal is acquired following the application of radio frequency (RF) pulse. The FID signal is analyzed and converted to a spectrumof unique resonance frequencies corresponding to different metabolites. 10,11 These unique resonance frequen- cies are determined by the chemical shifts of the protons
MRS can be a valuable tool in the analysis of intracranial
194 J La State Med Soc VOL 166 September/October 2014
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