Radiation Injury to the Normal Brain Measured by 3D‐Echo‐Planar Spectroscopic Imaging and Diffusion Tensor Imaging: Initial Experience

Chawla, Sanjeev; Wang, Sumei; Kim, Sungheon; Sheriff, Sulaiman; Lee, Peter; Rengan, Ramesh; Lin, Alexander P.; Melhem, Elias R.; Maudsley, Andrew A.; Poptani, Harish

doi:10.1111/jon.12070

Cited by 39 publications

(43 citation statements)

References 45 publications

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“…Short-term changes in FA indices after treatment have been reported in previous studies on adult patients with brain tumor treated by photon therapy (9,15,16,25). In contrast to our results, however, more severe and progressive changes were often observed.…”

Section: Comparison To Previous Dti Studies Of Photon Therapycontrasting

confidence: 95%

Effects of Surgery and Proton Therapy on Cerebral White Matter of Craniopharyngioma Patients

Hua

Ogg

et al. 2014

International Journal of Radiation Oncology*Biology*Physics

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Purpose-To determine the radiation dose-effect on the structural integrity of cerebral white matter in craniopharyngioma patients receiving surgery and proton therapy.Methods and Materials-Fifty-one patients (aged 2.1-19.3 years) with craniopharyngioma underwent surgery and proton therapy in a prospective therapeutic trial. Anatomical magnetic resonance images acquired after surgery but before proton therapy were inspected to identify white matter structures intersected by surgical corridors and catheter tracks. Longitudinal diffusion tensor imaging (DTI) was performed to measure microstructural integrity changes in cerebral white matter. Fractional anisotropy (FA) derived from DTI was statistically analyzed for 51 atlasbased white matter structures of the brain to determine radiation dose-effect. FA in surgeryaffected regions in the corpus callosum was compared to that in its intact counterpart to determine whether surgical defects affect radiation dose-effect.Results-Surgical defects were seen most frequently in the corpus callosum because of transcallosal resection of tumors and insertion of ventricular or cyst catheters. The longitudinal DTI data indicated reductions in FA 3 months after therapy, which was followed by a recovery in most white matter structures. A greater FA reduction was correlated with a higher radiation dose in 20 white matter structures, indicating a radiation dose-effect. The average FA in the surgery- Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. HHS Public Access Author Manuscript Author ManuscriptAuthor ManuscriptAuthor Manuscript affected regions before proton therapy was smaller (P =0.0001) than that in their non-surgery affected counterparts with more intensified subsequent reduction of FA (P=0.0083) after therapy, suggesting that surgery accentuated the radiation dose-effect.Conclusions-DTI data suggest that mild radiation dose-effects occur in patients with craniopharyngioma receiving surgery and proton therapy. Surgical defects present at the time of proton therapy appear to accentuate the radiation dose-effect longitudinally. This study supports consideration of pre-existing surgical defects and their locations in proton therapy planning and studies of treatment effect.

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Section: Comparison To Previous Dti Studies Of Photon Therapycontrasting

confidence: 95%

Effects of Surgery and Proton Therapy on Cerebral White Matter of Craniopharyngioma Patients

Hua

Ogg

et al. 2014

International Journal of Radiation Oncology*Biology*Physics

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“…MRSI data were obtained using a volumetric acquisition resulting in full coverage of the brain with field of view (FOV) 280 × 280 × 180 mm 3 and 64 × 64 × 32 voxels with effective voxel size ~1.0 mL (16). A second MRSI dataset from the water signal, referred to as the “water reference,” was acquired simultaneously in an interleaved fashion and with parameters identical to those for the metabolite MRSI signal.…”

Section: Methods and Methodsmentioning

confidence: 99%

Volumetric Spectroscopic Imaging of Glioblastoma Multiforme Radiation Treatment Volumes

Parra¹,

Maudsley²,

Gupta³

et al. 2014

International Journal of Radiation Oncology*Biology*Physics

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Purpose Magnetic resonance (MR) imaging and computed tomography (CT) are used almost exclusively in radiation therapy planning of glioblastoma multiforme (GBM), despite their well-recognized limitations. MR spectroscopic imaging (MRSI) can identify biochemical patterns associated with normal brain and tumor, predominantly by observation of choline (Cho) and N-acetylaspartate (NAA) distributions. In this study, volumetric 3-dimensional MRSI was used to map these compounds over a wide region of the brain and to evaluate metabolite-defined treatment targets (metabolic tumor volumes [MTV]). Methods and Materials Volumetric MRSI with effective voxel size of ~1.0 mL and standard clinical MR images were obtained from 19 GBM patients. Gross tumor volumes and edema were manually outlined, and clinical target volumes (CTVs) receiving 46 and 60 Gy were defined (CTV46 and CTV60, respectively). MTVCho and MTVNAA were constructed based on volumes with high Cho and low NAA relative to values estimated from normal-appearing tissue. Results The MRSI coverage of the brain was between 70% and 76%. The MTVNAA were almost entirely contained within the edema, and the correlation between the 2 volumes was significant (r=0.68, P=.001). In contrast, a considerable fraction of MTVCho was outside of the edema (median, 33%) and for some patients it was also outside of the CTV46 and CTV60. These untreated volumes were greater than 10% for 7 patients (37%) in the study, and on average more than one-third (34.3%) of the MTVCho for these patients were outside of CTV60. Conclusions This study demonstrates the potential usefulness of whole-brain MRSI for radiation therapy planning of GBM and revealed that areas of metabolically active tumor are not covered by standard RT volumes. The described integration of MTV into the RT system will pave the way to future clinical trials investigating outcomes in pa tients treated based on metabolic information.

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“…3D‐echo planar spectroscopic imaging (EPSI) allows acquisition of volumetric metabolite maps with high spatial resolution, minimizing partial volume effects . The potential of 3D‐EPSI has been reported in characterizing glioma grades, mapping glycine distribution in gliomas, planning radiation therapy for GBM patients, identifying residual tumor following radiation therapy, evaluating response to epigenetic modifying agents in recurrent GBM, evaluating treatment response to tumor treating fields (TTFields), and assessing the effect of whole brain radiation therapy on normal brain parenchyma in patients with metastases . However, its utility in differentiating between TP and PsP has not been investigated.…”

Section: Introductionmentioning

confidence: 99%

Three‐dimensional echo planar spectroscopic imaging for differentiation of true progression from pseudoprogression in patients with glioblastoma

et al. 2018

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Accurate differentiation of true progression (TP) from pseudoprogression (PsP) in patients with glioblastomas (GBMs) is essential for planning adequate treatment and for estimating clinical outcome measures and future prognosis. The purpose of this study was to investigate the utility of three‐dimensional echo planar spectroscopic imaging (3D‐EPSI) in distinguishing TP from PsP in GBM patients. For this institutional review board approved and HIPAA compliant retrospective study, 27 patients with GBM demonstrating enhancing lesions within six months of completion of concurrent chemo‐radiation therapy were included. Of these, 18 were subsequently classified as TP and 9 as PsP based on histological features or follow‐up MRI studies. Parametric maps of choline/creatine (Cho/Cr) and choline/N‐acetylaspartate (Cho/NAA) were computed and co‐registered with post‐contrast T 1 ‐weighted and FLAIR images. All lesions were segmented into contrast enhancing (CER), immediate peritumoral (IPR), and distal peritumoral (DPR) regions. For each region, Cho/Cr and Cho/NAA ratios were normalized to corresponding metabolite ratios from contralateral normal parenchyma and compared between TP and PsP groups. Logistic regression analyses were performed to obtain the best model to distinguish TP from PsP. Significantly higher Cho/NAA was observed from CER (2.69 ± 1.00 versus 1.56 ± 0.51, p = 0.003), IPR (2.31 ± 0.92 versus 1.53 ± 0.56, p = 0.030), and DPR (1.80 ± 0.68 versus 1.19 ± 0.28, p = 0.035) regions in TP patients compared with those with PsP. Additionally, significantly elevated Cho/Cr (1.74 ± 0.44 versus 1.34 ± 0.26, p = 0.023) from CER was observed in TP compared with PsP. When these parameters were incorporated in multivariate regression analyses, a discriminatory model with a sensitivity of 94% and a specificity of 87% was observed in distinguishing TP from PsP. These results indicate the utility of 3D‐EPSI in differentiating TP from PsP with high sensitivity and specificity.

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Radiation Injury to the Normal Brain Measured by 3D‐Echo‐Planar Spectroscopic Imaging and Diffusion Tensor Imaging: Initial Experience

Abstract: Our preliminary findings suggest that 3D-EPSI and DTI may provide quantitative measures of radiation induced injury to the normal brain.

Cited by 39 publications

References 45 publications

Effects of Surgery and Proton Therapy on Cerebral White Matter of Craniopharyngioma Patients

Effects of Surgery and Proton Therapy on Cerebral White Matter of Craniopharyngioma Patients

Volumetric Spectroscopic Imaging of Glioblastoma Multiforme Radiation Treatment Volumes

Three‐dimensional echo planar spectroscopic imaging for differentiation of true progression from pseudoprogression in patients with glioblastoma

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