Molecular MRI differentiation between primary central nervous system lymphomas and high-grade gliomas using endogenous protein-based amide proton transfer MR imaging at 3 Tesla

To show the ability of using the amide proton transfer-weighted (APTW) MRI signals as imaging biomarkers to differentiate primary central nervous system lymphomas (PCNSLs) from high-grade gliomas (HGGs). Eleven patients with lymphomas and 21 patients with HGGs were examined. Magnetization-transfer (MT) spectra over an offset range of +/- 6 ppm and the conventional MT ratio (MTR) at 15.6 ppm were acquired. The APTW signals, total chemical-exchange-saturation-transfer signal (integral between 0 and 5 ppm, CESTtotal), and MTR signal were obtained and compared between PCNSLs and HGGs. The diagnostic performance was assessed with the receiver operating characteristic (ROC) curve analysis. The PCNSLs usually showed more homogeneous APTW hyperintensity (spatially compared to normal brain tissue) than the HGGs. The APTW(max), APTW(max-min) and CESTtotal signal intensities were significantly lower (P < 0.05, 0.001 and 0.05, respectively), while the APTW(min) and MTR were significantly higher (both P < 0.01) in PCNSL lesions than in HGG lesions. The APTW values in peritumoral oedema were significantly lower for PCNSLs than for HGGs (P < 0.01). APTW(max-min) had the highest area under the ROC curve (0.963) and accuracy (94.1 %) in differentiating PCNSLs from HGGs. The protein-based APTW signal would be a valuable MRI biomarker by which to identify PCNSLs and HGGs presurgically. aEuro cent PCNSLs overall showed more homogeneous APTW hyperintensity than HGGs. aEuro cent Maximum APTW signals were lower in PCNSL lesions than in HGG lesions. aEuro cent MTR signals were higher in PCNSLs than in HGGs. aEuro cent APTW heterogeneity had the highest accuracy in differentiating PCNSLs from HGGs.