ABSTRACT
PURPOSE: To use magnetic resonance (MR) spectroscopy to characterize clinical isolates of Cryptococcus neoformans and a glioma cell line in culture and 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 neoformans, three of Candida albicans, three of Aspergillus fumigatus, three of Saccharomyces cerevisiae) and a C6 glioma cell line. Cerebral biopsy specimens were obtained 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 homo- and heteronuclear two-dimensional correlation spectra. RESULTS: MR spectra of C neoformans and cerebral cryptococcomas--but not of other fungi, healthy brains, or gliomas--were dominated by resonances from the cytosolic disaccharide alpha,alpha-trehalose. This spectral pattern was different from that of gliomas, which was dominated by lipids and an increased choline-creatine ratio, and that of healthy brain. CONCLUSION: A remarkably high concentration of alpha,alpha-trehalose in relation to other metabolites that are visible with MR spectroscopy is diagnostic of C neoformans. Cerebral cryptococcomas are an uncommon but serious manifestation of cryptococcosis in humans. Application of these results to the noninvasive diagnosis of cerebral cryptococcomas would help reduce the risk and expense of unnecessary surgery or biopsy and expedite patient treatment.
Subject(s)
Brain Neoplasms/diagnosis , Central Nervous System Fungal Infections/diagnosis , Cryptococcosis/diagnosis , Cryptococcus neoformans/isolation & purification , Glioma/diagnosis , Magnetic Resonance Spectroscopy/methods , Animals , Biopsy, Needle , Diagnosis, Differential , Disease Models, Animal , Female , Male , Rats , Rats, Inbred F344 , Rats, Wistar , Reference Values , Sensitivity and Specificity , Tumor Cells, CulturedABSTRACT
The detection of breast cancer in women using magnetic resonance imaging (MRI) is increasingly used as a supplement to X-ray mammography. Furthermore, proton MR spectroscopy (1H MRS) has detected alterations in lipid profiles that are linked with tumor development and progression in human biopsy tissue. Because normal "resting" breast is highly active, it is necessary to consider that any alterations observed in lipid profiles may not be indicative of breast tumor development. The purpose of this study was to assess the changes in lipid composition in the breast throughout the menstrual cycle in "normals" using MRS at 4.0 T. Five women with no known history of breast disease were subject to biweekly MRS breast examinations. MRS results showing water and fat resonances revealed cyclic changes in the lipid content throughout the duration of the menstrual cycle. In particular, intensity changes were seen in methylene (-CH2-) and allylic methylene (CH2CH2*CH=) resonances at 2.1 ppm and 1.3 ppm, respectively. These intensity changes assumed a similar cyclic trend for each subject over the 28 days that correlate with the follicular, ovulatory, and luteal phases of the menstrual cycle. The results obtained may indicate cell synthesis or metabolic activity in the breast during the menstrual cycle and provide valuable information pertinent to lipid responses associated with breast disease.
