Early volume reduction of the hippocampus after whole-brain radiation therapy: an automated brain structure segmentation study

Takeshita, Yohei; Watanabe, Keita; Kakeda, Shingo; Hamamura, Toshihiko; Sugimoto, Katsuhisa; Masaki, Hiromi; Ueda, Issei; Igata, Natsuki; Ohguri, Takayuki; Korogi, Yukunori

doi:10.1007/s11604-019-00895-3

Cited by 16 publications

(16 citation statements)

References 34 publications

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“…For SRS of the corticospinal tract, Maruyama et al (40) proposed a 5% risk of motor complication when the volume receiving 20 and 25 Gy exceeded 58 mm³ and 21 mm², respectively. Based on a neuroanatomical target theory for a patient collective treated by whole-brain radiotherapy with boost in conventional fractionation (1.8-2Gy/fraction), Pfeiffer et al (41) proposed that cognitive outcomes were affected by the volume of the left hippocampus receiving 10 Gy and by the volume of the left precentral gyrus receiving 40 Gy, among a range of other regions.…”

Section: Clinical Significance Of the Dosimetric Improvementsmentioning

confidence: 99%

“…For the hippocampus, recent radiotherapy optimization studies have aimed at reducing maximum dose to 16-17 Gy and minimum dose to 9 Gy in hippocampus-sparing whole-brain radiotherapy (14,25). However, while a significant correlation was observed between mean dose to the left hippocampus and cognitive deterioration (25) as well as hippocampal volume reduction (41), no dose cut-off was defined in these studies. Hippocampus volume loss was observed to be significant one year after high-dose radiotherapy (> 40 Gy), but not after low-dose radiotherapy (< 10 Gy) by Seibert et al (42).…”

Section: Clinical Significance Of the Dosimetric Improvementsmentioning

confidence: 99%

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Optimizing Adjuvant Stereotactic Radiotherapy of Motor-Eloquent Brain Metastases: Sparing the nTMS-Defined Motor Cortex and the Hippocampus

et al. 2021

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Brain metastases can effectively be treated with surgical resection and adjuvant stereotactic radiotherapy (SRT). Navigated transcranial magnetic stimulation (nTMS) has been used to non-invasively map the motor cortex prior to surgery of motor eloquent brain lesions. To date, few studies have reported the integration of such motor maps into radiotherapy planning. The hippocampus has been identified as an additional critical structure of radiation-induced deficits. The aim of this study is to assess the feasibility of selective dose reduction to both the nTMS-based motor cortex and the hippocampi in SRT of motor-eloquent brain metastases. Patients with motor-eloquent brain metastases undergoing surgical resection and adjuvant SRT between 07/2014 and 12/2018 were retrospectively analyzed. The radiotherapy treatment plans were retrieved from the treatment planning system (“original” plan). For each case, two intensity-modulated treatment plans were created: the “motor” plan aimed to reduce the dose to the motor cortex, the “motor & hipp” plan additionally reduce the dose to the hippocampus. The optimized plans were compared with the “original” plan regarding plan quality, planning target volume (PTV) coverage, and sparing of organs at risk (OAR). 69 plans were analyzed, all of which were clinically acceptable with no significant differences for PTV coverage. All OAR were protected according to standard protocols. Sparing of the nTMS motor map was feasible: mean dose 9.66 ± 5.97 Gy (original) to 6.32 ± 3.60 Gy (motor) and 6.49 ± 3.78 Gy (motor & hipp), p<0.001. In the “motor & hipp” plan, dose to the ipsilateral hippocampi could be significantly reduced (max 1.78 ± 1.44 Gy vs 2.49 ± 1.87 Gy in “original”, p = 0.003; mean 1.01 ± 0.92 Gy vs. 1.32 ± 1.07 Gy in “original”, p = 0.007). The study confirms the results from previous studies that inclusion of nTMS motor information into radiotherapy treatment planning is possible with a relatively straightforward workflow and can achieve reduced doses to the nTMS-defined motor area without compromising PTV coverage. Furthermore, we demonstrate the feasibility of selective dose reduction to the hippocampus at the same time. The clinical significance of these optimized plans yet remains to be determined. However, with no apparent disadvantages these optimized plans call for further and broader exploration.

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Section: Clinical Significance Of the Dosimetric Improvementsmentioning

confidence: 99%

Section: Clinical Significance Of the Dosimetric Improvementsmentioning

confidence: 99%

Optimizing Adjuvant Stereotactic Radiotherapy of Motor-Eloquent Brain Metastases: Sparing the nTMS-Defined Motor Cortex and the Hippocampus

et al. 2021

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“…Radiotherapy induced brain atrophy has been observed across the whole brain [4][5][6][7], hippocampus [8][9][10][11], amygdala [12] and cerebellum [13]. The findings show consistently that the amount of tissue loss is dose dependent [5,13,14].…”

Section: Introductionmentioning

confidence: 84%

Overestimation of grey matter atrophy in glioblastoma patients following radio(chemo)therapy

Gommlich

Raschke

Petr

et al. 2021

Magn Reson Mater Phy

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Objective Brain atrophy has the potential to become a biomarker for severity of radiation-induced side-effects. Particularly brain tumour patients can show great MRI signal changes over time caused by e.g. oedema, tumour progress or necrosis. The goal of this study was to investigate if such changes affect the segmentation accuracy of normal appearing brain and thus influence longitudinal volumetric measurements. Materials and methods T1-weighted MR images of 52 glioblastoma patients with unilateral tumours acquired before and three months after the end of radio(chemo)therapy were analysed. GM and WM volumes in the contralateral hemisphere were compared between segmenting the whole brain (full) and the contralateral hemisphere only (cl) with SPM and FSL. Relative GM and WM volumes were compared using paired t tests and correlated with the corresponding mean dose in GM and WM, respectively. Results Mean GM atrophy was significantly higher for full segmentation compared to cl segmentation when using SPM (mean ± std: ΔVGM,full = − 3.1% ± 3.7%, ΔVGM,cl = − 1.6% ± 2.7%; p < 0.001, d = 0.62). GM atrophy was significantly correlated with the mean GM dose with the SPM cl segmentation (r = − 0.4, p = 0.004), FSL full segmentation (r = − 0.4, p = 0.004) and FSL cl segmentation (r = -0.35, p = 0.012) but not with the SPM full segmentation (r = − 0.23, p = 0.1). Conclusions For accurate normal tissue volume measurements in brain tumour patients using SPM, abnormal tissue needs to be masked prior to segmentation, however, this is not necessary when using FSL.

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“…Quantitative volumetric MRI measurements have been used to observe radiationinduced anatomical differences. Several studies focused on volumetric changes of the whole brain (WB), white matter (WM), and grey matter (GM) [29][30][31][32][33][34][35][36][37], while other studies evaluated volume changes in specific brain structures such as the hippocampus [38][39][40][41][42][43][44], amygdala [44,45], corpus callosum [46], subregions of the cerebral cortex [47][48][49][50], and cerebellum [51,52]. Additionally, in some studies, the correlation of brain volume loss with cognitive decline [31,33,34,52], aging or patient age at radiation [30,32,33,36,37,42,45,46,[50][51][52] was investigated.…”

Section: Determination Of Anatomical/morphological Changes In Normal-mentioning

confidence: 99%

MR Image Changes of Normal-Appearing Brain Tissue after Radiotherapy

Witzmann

Raschke

Troost

2021

Cancers

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Radiotherapy is part of the standard treatment of most primary brain tumors. Large clinical target volumes and physical characteristics of photon beams inevitably lead to irradiation of surrounding normal brain tissue. This can cause radiation-induced brain injury. In particular, late brain injury, such as cognitive dysfunction, is often irreversible and progressive over time, resulting in a significant reduction in quality of life. Since 50% of patients have survival times greater than six months, radiation-induced side effects become more relevant and need to be balanced against radiation treatment given with curative intent. To develop adequate treatment and prevention strategies, the underlying cause of radiation-induced side-effects needs to be understood. This paper provides an overview of radiation-induced changes observed in normal-appearing brains measured with conventional and advanced MRI techniques and summarizes the current findings and conclusions. Brain atrophy was observed with anatomical MRI. Changes in tissue microstructure were seen on diffusion imaging. Vascular changes were examined with perfusion-weighted imaging and susceptibility-weighted imaging. MR spectroscopy revealed decreasing N-acetyl aspartate, indicating decreased neuronal health or neuronal loss. Based on these findings, multicenter prospective studies incorporating advanced MR techniques as well as neurocognitive function tests should be designed in order to gain more evidence on radiation-induced sequelae.

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Early volume reduction of the hippocampus after whole-brain radiation therapy: an automated brain structure segmentation study

Cited by 16 publications

References 34 publications

Optimizing Adjuvant Stereotactic Radiotherapy of Motor-Eloquent Brain Metastases: Sparing the nTMS-Defined Motor Cortex and the Hippocampus

Optimizing Adjuvant Stereotactic Radiotherapy of Motor-Eloquent Brain Metastases: Sparing the nTMS-Defined Motor Cortex and the Hippocampus

Overestimation of grey matter atrophy in glioblastoma patients following radio(chemo)therapy

MR Image Changes of Normal-Appearing Brain Tissue after Radiotherapy

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