The aim of the work described in this thesis was to investigate the value of
conventional, perfusion- and diffusion-weighted magnetic resonance imaging (MRI)
in patients with histology-proven low-grade gliomas (LGG), and the potential role of
these methods in the management of patients with these brain tumours.
Thirty-six patients were studied at the National Hospital for Neurology and
Neurosurgery using conventional, perfusion-weighted and diffusion-weighted MRI
at study entry and 6 monthly intervals thereafter. At each visit, tumour volume,
maximum rCBV and ADC histogram measures were calculated. This is a unique
cohort, as patients were treatment free until malignant transformation was diagnosed,
which translates the natural history of these brain tumours. It is unlikely to find such
a specific cohort as most of the patients receive treatment after the initial diagnosis
of low grade gliomas.
Chapters 1 and 2 of this thesis describe the theoretical basis of the MRI techniques
used, and summarise the natural history and imaging aspects of cerebral gliomas.
Chapter 3 describes a methodological study relating to tumour perfusion
measurement: since the inclusion or exclusion of intratumoural vessels may
influence the quantification of relative cerebral blood volume (rCBV), a study was
conducted to choose the best ROI placement technique to be used for the rCBV
measurements included in this thesis. It was shown that only the approach which
excluded intratumoural vessels demonstrated a significant association between rCBV
values and tumour subtypes (astrocytomas, oligodendrogliomas and
oligoastrocytomas) and therefore this technique was used in all subsequent rCBV
measurements
