International Journal of Radiation Oncology*Biology*Physics
Poster Viewing AbstractEchoplanar Magnetic Resonance Spectroscopic Imaging Before and Following Radiation Therapy in Patients With High-Grade Glioma
Section snippets
Purpose/Objective(s)
To determine if volumetric echo-planar spectroscopic imaging (EPSI) performed at 1.5T can be used to identify residual post-operative tumor in patients with high grade glioma, and to monitor the effects of radiation therapy.
Materials/Methods
Twenty patients (10F, 53.9±14.3 years) with high grade glioma were evaluated post-surgery but prior to initiating radiation therapy (RT, 60 Gy) and concomitant temozolomide (TMZ). A follow-up scan was performed after 6 weeks of RT. Water and lipid suppressed spin-echo EPSI was performed with the following parameters: TR/TE = 2000/70 ms, nominal voxel size ≈ 0.5 ml. ROIs were selected in the lesion (as identified on both the choline (Cho) map and conventional MR images) or in the peri-cavity
Results
Mean NAA/Crc was significantly lower in the lesions compared to the contralateral hemisphere on both pre and post scans (P<0.0001, 2-tailed unpaired t-test). Also, on the pre scan, mean Cho/Crc in lesion was significantly higher than control (P = 0.016), but was not significantly different from control post-RT (P = 0.419). Lesion NAA/Crc was similar between the pre (0.74 ± 0.08, mean ± SEM) and post (0.68 ± 0.10) scans (P = 0.360). Cho/Crc ratio was significantly reduced from the pre (0.41 ±
Conclusion
This study confirms that post-surgical, residual tumor (i.e. elevated Cho) can be detected by EPSI performed at 1.5T prior to RT. In addition, there was a significant reduction of tumor Cho/Crc ratio following 6 weeks of RT, suggesting that EPSI may be useful for monitoring treatment response. Lesion NAA/Crc increases post-treatment may reflect decreased tumor infiltration and/or recovery of neuronal tissue within the lesion ROI, and correlated with longer PRS.
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Author Disclosure: D.D. Lin: None. Y. Lin: None. K. Link: None. A. Marsman: None. A. Zessler: None. S. Usama: None. S. Sheriff: None. A.A. Maudsley: None. L.R. Kleinberg: None. P.B. Barker: None.