MRI - Teenage Brian Tumours
Assessment of the structure and function of brain tumours in teenagers using MRI before and following treatment.
Overview:
Gliomas account for approximately 50% of all brain tumours in the adolescent and young adult population. Although most of these patients have an excellent outcome, a small but significant proportion will either relapse or experience tumour progression after definitive treatment. The traditional and accepted criteria to determine tumour response in oncology, namely the Response Evaluation Criteria in Solid Tumours (RECIST) and Macdonald criteria, use decrease in tumour size and lesion enhancement as an indicator of successful therapy. As more aggressive combined modality treatments are being investigated for the management of gliomas, it has become increasingly important to identify earlier indicators of regional response or regression. This would enable earlier initiation of effective treatment options, and thereby optimize patient outcome.
Although considerable work has been done in this area using CT in body tumours, several areas within the field of MRI have seen considerable advances making MRI an ideal tool: modern contrast media, advanced morphologic approaches and several functional techniques, in the visualization of tumour perfusion or tumour cell metabolism. Proton magnetic resonance spectroscopy (MRS) allows the non-invasive detection of brain metabolites. Increasing lactate to creatine and choline to creatine levels are associated with tumour recurrence in adult gliomas, noted before progression on conventional neuroimaging. MRI perfusion characterizes tumour vasculature and has been shown to correlate with tumour grade. Recent studies have demonstrated the value of this technique in predicting survival in high-grade gliomas during radiotherapy and as an imaging biomarker for early cancer outcome. Diffusion weighted imaging (DWI) assesses free water movement in tissues and a recent study in glioblastoma multiforme treated with bevacizumab has shown that the Apparent Diffusion Coefficent (ADC) of tumours prior to treatment can stratify progression-free survival.
The success or failure of new and/or augmented treatments will be closely linked to appropriate patient selection. Fortunately, the clinical proliferation of “functional” MRI capable scanners and techniques provides an opportune time for the development of new and likely improved patient stratification methods. Our study will assess a multitude of functional MRI features in order to determine those that are predictive of tumour response to chemoradiotherapy. In addition, we will establish the ranges of these parameters found in disease, which could lead to potential improvements in imaging diagnosis of glioma.
Finally, an important correlation to imaging and clinical outcome data will be the histological phenotype and the molecular profile of the brain tumour. It will be key to improving clinical management and ultimately patient survival.
Primary Study Aims:
- To evaluate whether pre-chemoradiotherapy and/or early post-chemoradiotherapy functional MRI features (diffusion, dynamic contrast enhancement, spectroscopy and blood oxygenation level dependent contrast) can predict subsequent tumour response in adolescents/young adult patients with glioma.
Secondary Study Aims:
- To identify the ranges of individual functional MRI parameters associated with the presence of disease prior to and following treatment.