Human brain tumours have been investigated using proton and phosphorus nuclear magnetic resonance (NMR). The localization technique, chemical shift imaging has been used to obtain phosphorus spectra of tumours in vivo. High resolution proton spectroscopy has been performed on biopsy samples and extracts of human brain tumours. To obtain the localized phosphorus spectra, one dimensional chemical shift imaging with a surface coil was adapted to a 1.5 T Siemens Magnetom imager. The ratios of areas, PDE/ATP and PME/ATP were found to be higher in glioblastomas and astrocytomas than in normal brain. Pi/ATP and PCr/ATP were also high in astrocytomas. The pH of brain tumours ranged from alkaline to neutral, with meningiomas consistently having alkaline pH. A three dimensional localization sequence was written and tested on the Magnetom and used to obtain phosphorus spectra from the brains of normal volunteers. One dimensional $\sp1$H spectra, COSY spectra and T$\sb2$ data were obtained from ex vivo biopsy samples. A parameter, P, was defined as the ratio of the area between 3.4 and 3.1. ppm over the area between 1.5 ppm and 1.1 ppm. The parameter distinguished glioblastomas from astrocytomas and normal brain. This area parameter, P, also appeared to be indicative of malignant potential or biological aggressiveness. Crosspeaks in the ex vivo proton COSY spectra of brain specimens could be used to classify glioblastomas, astrocytomas, metastases to the brain, meningiomas and normal brain in agreement with histopathological diagnosis. The T$\sb2$ values at 1.3 ppm were fitted to a two exponential equation. The longer component could be used to separate clearly glioblastomas from normal brain, normal brain having a much longer long T$\sb2$ component. Astrocytomas formed a continuum of values between glioblastomas and normal brain, with the grade of the astrocytoma roughly correlating with the value of the long T$\sb2$ component. High resolution $\sp1$H spectroscopy of perchloric acid extracts of biopsy samples was performed. The extracts confirmed that lactate, acetate, creatine and choline derivatives, NAA, glutamate, glutamine, alanine, valine and leucine were present in the samples. Comparisons of extract and ex vivo spectra indicated that the 1.3 ppm peak in the ex vivo spectra is predominantly due to the methylene moiety of lipids.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/7681 |
| Date | January 1992 |
| Creators | Rutter, Allison. |
| Contributors | Smith, I. C. P., |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Detected Language | English |
| Type | Thesis |
| Format | 233 p. |
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