Radiation‐induced brain structural and functional abnormalities in presymptomatic phase and outcome prediction

Abstract

Radiation therapy, a major method of treatment for brain cancer, may cause severe brain injuries after many years. We used a rare and unique cohort of nasopharyngeal carcinoma patients with normal-appearing brains to study possible early irradiation injury in its presymptomatic phase before severe, irreversible necrosis happens. The aim is to detect any structural or functional imaging biomarker that is sensitive to early irradiation injury, and to understand the recovery and progression of irradiation injury that can shed light on outcome prediction for early clinical intervention. We found an acute increase in local brain activity that is followed by extensive reductions in such activity in the temporal lobe and significant loss of functional connectivity in a distributed, largescale, high-level cognitive function-related brain network. Intriguingly, these radiosensitive functional alterations were found to be fully or partially recoverable. In contrast, progressive late disruptions to the integrity of the related far-end white matter structure began to be significant after one year. Importantly, early increased local brain functional activity was predictive of severe later

Machine-learning based MRI radiomics models for early detection of radiation-induced brain injury in nasopharyngeal carcinoma

“…Conventional MR imaging can only be used to evaluate morphologic changes of late radiation injury to the temporal lobes. However, structural and functional MR imaging biomarker that is sensitive to early irradiation brain injury has been previously detected [19]. Leng X et al analyzed the microstructural dynamic alterations in all brain lobes after radiotherapy in NPC patients at different times, by using DTI for white matter and voxel-based morphometry for gray matter volume [20].…”

Local Diffusion Homogeneity Provides Supplementary Information in T2DM-Related WM Microstructural Abnormality Detection

“…Another widely used complementary non-invasive MRI technique is diffusion tensor imaging (DTI), which has higher resolution and better signal-to-noise ratio than fMRI and can sensitively detect changes of constrained molecular water diffusivity in the WM (Alexander et al, 2007). DTI has long been used as a sensitive and objective technique searching for subtle changes in WM in many diseases (O’Donnell and Westin, 2011; Guo W. et al, 2012; Wang et al, 2015; Ding et al, 2018). It is reasonable that WM changes in specific fiber tracts might have led to disrupted information exchange, thus deteriorating functional integration among brain regions (Wakana et al, 2004; Alexander et al, 2007; Reijmer et al, 2013b; Biessels and Reijmer, 2014; Moheet et al, 2015) and further causing cognitive deficits in T2DM.…”

Deep Longitudinal Feature Representations for Detection of Postradiotherapy Brain Injury at Presymptomatic Stage

“…Recently, functional imaging techniques, including functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), have been used to explore the invisible WM changes in the temporal lobes [9], [54]- [56]. However, three major drawbacks of these methods include time consumption for collecting additional nonstandard MRI sequences, unsatisfactory precision of current neck and head registration techniques, and limitation of the low spatial resolution for tract-based statistical analysis.…”