A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Significance: Contrast‐enhanced (CE) and Fluid attenuation inversion recovery (FLAIR) MRI are current standard of care tools for delineating radiation treatment targets in high‐grade glioma (HGG) patients. However, in the setting of retreatment, tumor regrowth and non‐tumor therapy‐related inflammation, known as post‐treatment radiation effect (PTRE), have identical MRI appearances. As a result, FLAIR MRI can be an unreliable tool for treatment planning. Surgical biopsy can definitively distinguish recurrent tumors from PTRE but has many disadvantages, namely operative risk and cost. Dynamic Susceptibility‐weighted Contrast‐ Enhanced (DSC) MRI Perfusion can non‐invasively detect distinct characteristics of tumor and PTRE through measurements of relative cerebral blood volume (rCBV). PTRE exhibits decreased microvascular density, whereas tumor recurrence displays angiogenesis and microvascular proliferation. Thus, DSC‐MRI affords the opportunity to better define tumor burden within and possibly outside of these nonspecific regions.
Objective: To assess the extent with which rCBV maps correlate with re‐radiation treatment
plans in patients with recurrent tumor in order to identify potential differences in treatment planning.
Design: This study enrolled 8 previously treated HGG patients presenting for re‐irradiation of suspected recurrent tumor at a single hospital on an IRB‐approved trial. All patients underwent DSC‐MRI and routine MRI imaging prior to re‐irradiation treatment planning, and underwent treatment as per routine clinical protocol. Following therapy, rCBV and radiation dose maps were overlaid on conventional MR to delineate differences in identified tumor burden.
Results: Of the 8 patients, four rCBV images showed evidence of tumor outside of the RT
planning volumes, while the other 4 showed fully treated tumor but with large volumes of uninvolved brain receiving radiation.
Conclusion: DSC‐MRI better identified unique regions of potential tumor burden in recurrent HGG patients compared to conventional MRI and could be used to improve radiation treatment planning in re‐radiated patients.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/528207 |
| Date | 04 1900 |
| Creators | Kim, Nathan |
| Contributors | The University of Arizona College of Medicine - Phoenix, Brachman, David MD |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
| Rights | Copyright © is held by the author. Digital access to this material is made possible by the College of Medicine - Phoenix, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
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