Cryptococcomas distinguished from gliomas with MR spectroscopy: An experimental rat and cell culture study

PURPOSE: To use magnetic resonance (MR) spectroscopy to characterize clinic al isolates of Cryptococcus neoformans and a glioma cell line in culture an d in experimental rats. MATERIALS AND METHODS: One- and two-dimensional hydrogen 1 MR spectra were acquired from fungi cultured in vitro (16 isolates of C. neoformqns, three of Candida albicans, three of Aspergillus fumigatus, three of Saccharomyces cerevisiae) and a C6 glioma cell line. Cerebral biopsy specimens were obta ined from healthy rats and animals with experimental infections or gliomas (19 healthy brains, 20 cryptococcomas, and 19 gliomas). Unequivocal signal assignment was performed for cell suspensions and tissue samples by using h omo- and heteronuclear two-dimensional correlation spectra. RESULTS: MP spectra of C neoformans and cerebral cryptococcomas - but not o f other fungi, healthy brains, or gliomas - were dominated by resonances fr om the cytosolic disaccharide alpha,alpha-trehalose. This spectral pattern was different from that of gliomas, which was dominated by lipids and an in creased choline-creatine ratio, and that of healthy brain. CONCLUSION: A remarkably high concentration of alpha,alpha-trehalose in rel ation to other metabolites that are visible with MR spectroscopy is diagnos tic of C neoformans. Cerebral cryptococcomas are an uncommon but serious ma nifestation of cryptococcosis in humans. Application of these results to th e noninvasive diagnosis of cerebral cryptococcomas would help reduce the ri sk and expense of unnecessary surgery or biopsy and expedite patient treatm ent.