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Title: Toward Distinguishing Recurrent Tumor From Radiation Necrosis: DWI and MTC in a Gamma Knife–Irradiated Mouse Glioma Model

Purpose: Accurate noninvasive diagnosis is vital for effective treatment planning. Presently, standard anatomical magnetic resonance imaging (MRI) is incapable of differentiating recurring tumor from delayed radiation injury, as both lesions are hyperintense in both postcontrast T1- and T2-weighted images. Further studies are therefore necessary to identify an MRI paradigm that can differentially diagnose these pathologies. Mouse glioma and radiation injury models provide a powerful platform for this purpose. Methods and Materials: Two MRI contrasts that are widely used in the clinic were chosen for application to a glioma/radiation-injury model: diffusion weighted imaging, from which the apparent diffusion coefficient (ADC) is obtained, and magnetization transfer contrast, from which the magnetization transfer ratio (MTR) is obtained. These metrics were evaluated longitudinally, first in each lesion type alone–glioma versus irradiation – and then in a combined irradiated glioma model. Results: MTR was found to be consistently decreased in all lesions compared to nonlesion brain tissue (contralateral hemisphere), with limited specificity between lesion types. In contrast, ADC, though less sensitive to the presence of pathology, was increased in radiation injury and decreased in tumors. In the irradiated glioma model, ADC also increased immediately after irradiation, but decreased as the tumor regrew. Conclusions: ADC ismore » a better metric than MTR for differentiating glioma from radiation injury. However, MTR was more sensitive to both tumor and radiation injury than ADC, suggesting a possible role in detecting lesions that do not enhance strongly on T1-weighted images.« less
Authors:
;  [1] ; ;  [2] ;  [3] ;  [4] ;  [2] ;  [5] ;  [2] ;  [6] ;  [5] ;  [5] ;  [1]
  1. Department of Radiology, Washington University, St. Louis, Missouri (United States)
  2. Department of Radiation Oncology, Washington University, St. Louis, Missouri (United States)
  3. Department of Neurosurgery, Washington University, St. Louis, Missouri (United States)
  4. Department of Neuropathology, Washington University, St. Louis, Missouri (United States)
  5. (United States)
  6. Department of Chemistry, Washington University, St. Louis, Missouri (United States)
Publication Date:
OSTI Identifier:
22423832
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 90; Journal Issue: 2; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; BIOMEDICAL RADIOGRAPHY; BRAIN; DELAYED RADIATION EFFECTS; DIAGNOSIS; GLIOMAS; IRRADIATION; MICE; NECROSIS; NMR IMAGING; PLANNING; RADIATION INJURIES; SPECIFICITY