Early Detection of Radiation-Induced Injury and Prediction of Cognitive Deficit by MRS Metabolites in Radiotherapy of Low-Grade Glioma.

Zahra Alirezaei,Masoud Hassanpour,Fariba Davanian,Alireza Amouheidari,Mohammad-Reza Nazem-Zadeh,Parvaneh Shokrani,Sajjad Iraji,Adomas Bunevicius

doi:10.1155/2021/6616992

Abstract

Purpose To compare the sensitivity of MRS metabolites and MoCA and ACE-R cognitive tests in the detection of radiation-induced injury in low grade glioma (LGG) patients in early and early delayed postradiation stages. Methods MRS metabolite ratios of NAA/Cr and Cho/Cr, ACE-R and MoCA cognitive tests, and dosimetric parameters in corpus callosum were analyzed during RT and up to 6-month post-RT for ten LGG patients. Results Compared to pre RT baseline, a significant decline in both NAA/Cr and Cho/Cr in the corpus callosum was seen at the 4th week of RT, 1, 3, and 6-month post-RT. These declines were detected at least 3 months before the detection of declines in cognitive functions by ACE-R and MoCA tools. Moreover, NAA/Cr alterations at 4th week of RT and 1-month post-RT were significantly negatively correlated with the mean dose received by the corpus callosum, as well as the corpus callosum 40 Gy dose volume, i.e., the volume of the corpus callosum receiving a dose greater than 40 Gy. Conclusion MRS-based biomarkers may be more sensitive than the state-of-the-art cognitive tests in the prediction of postradiation cognitive impairments. They would be utilized in treatment planning and dose sparing protocols, with a specific focus on the corpus callosum in the radiation therapy of LGG patients.

Highlights

Radiation therapy (RT) plays a major role in treatment of low-grade glioma (LGG) patients
It was demonstrated that the alteration in MR spectroscopy (MRS) metabolites occurred earlier than the cognitive assessments measured by Addenbrooke Cognitive Examination (ACE)-R
This study specified a significant variation of MRS metabolite values in the corpus callosum starting at early phases after RT of LGG patients, which remained evident for early delayed and delayed phases

Summary

Introduction

Radiation therapy (RT) plays a major role in treatment of low-grade glioma (LGG) patients. Depending on the time between the onset of RT and the clinical manifestations, the effects are classified as early, early delayed, and late delayed. Effects occur during or shortly after the RT and characterized by symptoms of fatigue, dizziness, and increased intracranial pressure [3, 4]. Delayed injuries occurring one to six months after RT generally show reversible symptoms such as global weakness and somnolence, resulting from a temporary demyelination. The more severe late delayed brain injury usually develops in and about 6month postradiation. These injuries may lead to severe irreversible neurological consequences without any visible sign

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