Improved analysis of H-1-MR spectra in the presence of mobile lipids

Focal brain lesions can be associated with proton magnetic resonance spectr a (H-1-MRS)-detectable mobile lipids, reflecting severe tissue degradation and necrosis. However, advanced fitting procedures, such as the LCModel, fa il to adequately fit spectra in the presence of lipid resonances. To overco me this, different approaches to generate lipid model spectra were compared using a phantom, real in vivo data, and simulated data. Twenty-six in vivo short-echo time (TE) H-1-MRS from 21 malignant gliomas, four infections, a nd one ischemia were analyzed to evaluate the performance of the modified L CModel fit. Adding simulated aliphatic resonances at 1.3 and 0.9 ppm improv ed the overall fitting quality remarkably and allowed good separation of la ctate and alanine. Also, a better differentiation of glioblastomas and anap lastic gliomas was achieved. In conclusion, we propose a simple way to effi ciently include lipid resonances in the LCModel, allowing a better fit of i n vivo short-TE H-1-MRS, and demonstrate the diagnostic potential of quanti tative assessment of mobile lipids in brain tumors. (C) 2001 Wiley-Liss, In c.