Adult glioma managment with selective biopsy, voxel-wise radiomics, and simultaneous PET/MR imaging

2020-07-30T00:48:42Z (GMT) by Emily Diller
Every year more than fourteen-thousand adults in the United States are diagnosed with glioma, the most common malignant tumor of the central nervous system. Gliomas arise from glue like glial cells and present with a range of grade and prognosis. Glioblastoma multiforme (GBM), a grade IV glioma, is the most common glioma subtype and carries dismal prognosis with fewer than one half of patients surviving one year after diagnosis. The standard treatment for GBM is resection followed by a cocktail of chemo and radiation therapy. Unfortunately, complete surgical resection is impossible for GBM, and intra-tumor heterogeneity, a GBM hallmark, negatively impacts chemo and radiation therapy efficacy. This thesis contains six chapters that evaluate advanced imaging and statistical methods that may be used to improve glioma management. Chapter one presents background information to establish the relationship of four subsequent studies with ranging topics on advanced imaging techniques, biopsy sampling, and radiomic analysis. In chapter two, a case report is presented that demonstrates the importance of advanced magnetic resonance imaging (MRI) such as arterial spin labeled (ASL) perfusion sequences. In this case, a patient with a benign cerebral lesion presents with receptive aphasia and of the imaging data acquired, only ASL showed decrease cerebral aphasia. Chapter three describes the impact biopsy selection has on correlation between prognostic and histologic features in 35 patients with GBM. Multiple biopsy selection methods were compared, resulting in a wide range in correlation significance. Chapter four presents different voxel-wise radiomic models in adult glioma patients. From one voxel-wise radiomic model, predicted disease compositions (PDC) were computed in 17 glioma patients and were able to significantly (α = 0.05) predict overall survival, tumor grade, and endothelial proliferation. Chapter five describes the feasibility and hardware constraints of simultaneous PET/MR imaging protocols. A dynamic infusion of fluorodeoxyglucose (FDG) was administered with simultaneous MR imaging including echo planar imaging (EPI) based sequences used for functional MRI (fMRI). Heat from the EPI sequences deposited in the PET detector hardware and resulted in significant hardware failure. Finally, chapter six provides outlook and application to glioma clinical management considering the methods and findings presented in each study.

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