Sodium magnetic resonance imaging in the setting of tumor and stroke treatment.

摘要

Determining the viability of cells subjected to adverse conditions is important to the diagnosis and monitoring of treatment for both acute stroke and malignant cerebral tumors. Acute stroke occurs when vital nutrients are blocked from reaching brain parenchyma, causing cell death. Diagnostic imaging commonly performed on acute stroke patients provides clear indication of the ischemic insult, but not of its progression to infarction. The decision to treat is currently based on patient status within a 3 hour window from first indication of symptoms, rather than the realized health of the affected cells. The additional diagnosis of the viability of the tissue involved can improve the effectiveness of patient treatment. High grade tumors are heterogeneous masses of cells that are excessively proliferating. Thus, survival of the patient depends on fully eradicating those tumor cells. Tumor treatment uses surgery, radiation, and chemotherapy to selectively remove neoplastic cells while minimizing collateral damage to normal brain parenchyma. The treatment is guided by historical data on population survival studies and not on the viability of the cells affected by the treatment. The intent of this engineering project is to develop the tools necessary for the in vivo measurement and monitoring of cell viability, and to demonstrate their usefulness in the setting of acute stroke and tumor treatment.;Cell viability can be monitored by quantitative imaging of a biomarker that quantifies the current functioning of the cell. One important biomarker is the macroscopic [Na] of a cell. Normal functioning cells continually expend significant energy maintaining cellular Na+ ion homeostasis. The macroscopic [Na] resulting from Na+ ion homeostasis, in both viable and nonviable cells, is determinable and measurable by 23Na Magnetic Resonance Imaging. The first hypothesis of this project is that tool(s) can be developed to accurately produce [Na] maps from acquired 23Na density weighted image acquisitions. Another measurable contribution to cell health is a sufficient supply of blood to the tissue. The second hypothesis is that tool(s) can be developed to efficiently and accurately extract perfusion measurements from Dynamic Susceptibility Contrast Magnet Resonance Imaging (DSC-MRI). The third hypothesis for the proposed research is that 23Na MRI can be used to monitor the viability of cells and in conjunction with DSC-MRI perfusion imaging provide clinically useful information in acute stroke and tumor treatment.