DCE and DSC MR perfusion imaging in the differentiation of recurrent tumour from treatment-related changes in patients with glioma

Advanced magnetic resonance imaging methods for planning and monitoring radiation therapy in patients with high-grade glioma

This review explores how the integration of advanced imaging methods with high-quality anatomical images significantly improves the characterization, target definition, assessment of response to therapy, and overall management of patients with high-grade glioma. Metrics derived from diffusion-, perfusion-, and susceptibility-weighted magnetic resonance imaging in conjunction with magnetic resonance spectroscopic imaging, allows us to characterize regions of edema, hypoxia, increased cellularity, and necrosis within heterogeneous tumor and surrounding brain tissue. Quantification of such measures may provide a more reliable initial representation of tumor delineation and response to therapy than changes in the contrast-enhancing or T2 lesion alone and have a significant effect on targeting resection, planning radiation, and assessing treatment effectiveness. In the long term, implementation of these imaging methodologies can also aid in the identification of recurrent tumor and its differentiation from treatment-related confounds and facilitate the detection of radiationinduced vascular injury in otherwise normal-appearing brain tissue.

Permeability imaging in pediatric brain tumors

While traditional computed tomography (CT) and magnetic resonance (MR) imaging illustrate the structural morphology of brain pathology, newer, dynamic imaging techniques are able to show the movement of contrast throughout the brain parenchyma and across the blood-brain barrier (BBB). These data, in combination with pharmacokinetic models, can be used to investigate BBB permeability, which has wide-ranging applications in the diagnosis and management of central nervous system (CNS) tumors in children. In the first part of this paper, we review the technical principles underlying four imaging modalities used to evaluate BBB permeability: PET, dynamic CT, dynamic T1-weighted contrast-enhanced MR imaging, and dynamic T2-weighted susceptibility contrast MR. We describe the data that can be derived from each method, provide some caveats to data interpretation, and compare the advantages and disadvantages of the different techniques. In the second part of this paper, we review the clinical applications that have been reported with permeability imaging data, including diagnosing the nature of a lesion found on imaging (neoplastic versus non-neoplastic, tumor type, tumor grade, recurrence versus pseudoprogression), predicting the natural history of a tumor, monitoring angiogenesis and tracking response to anti-angiogenic agents, optimizing chemotherapy agent selection, and aiding in the development of new antineoplastic drugs and methods to increase local delivery of chemotherapeutics.