A meta-analysis of diffusion tensor imaging of substantia nigra in patients with Parkinson’s disease

Deng, Xiaoyan; Wang, Li; Yang, Tingting; Li, Rui; Yu, Gang

doi:10.1038/s41598-018-20076-y

Cited by 30 publications

(31 citation statements)

References 32 publications

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“…TheT2 weighted images capture the elevated levels of iron mainly in SNr (Du et al, ; Langley et al, ; Langley et al, ; Langley, Huddleston, Sedlacik, Boelmans, & Hu, ). A study by Langley et al demonstrated that T2‐weighted and NMS‐MRI are sensitive to different sub regions of SN (Langley et al, ), and the hypo‐intensity observed on T2 images is unreliable in localizing SNc (Deng et al, ; Langley et al, ; Wypijewska et al, ). A recent study also demonstrated that increase in T2* weighted hypo intense signal is an indication of increase in iron deposition related to PD pathology (Langley et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…For example, studies have employed T2 weighted, proton density weighted spin echo and inversion recovery based contrasts to precisely localize the SNc ROIs (Atasoy et al, 2004;Duguid, De La Paz, & DeGroot, 1986;Geng, Li, & Zee, 2006;Hutchinson & Raff, 2000;Oikawa, Sasaki, Tamakawa, Ehara, & Tohyama, 2002;Pujol, Junque, Vendrell, Grau, & Capdevila, 1992;Stern, Braffman, Skolnick, Hurtig, & Grossman, 1989;Tuite, Mangia, & Michaeli, 2013). However, in a conventional T2 weighted MRI, there is variability in the hypo-intensity associated with the SNc as a result of increased iron deposition, in addition to the reduction in neuromelanin content (Deng, Wang, Yang, Li, & Yu, 2018;Langley et al, 2015;Langley et al, 2016;Wypijewska et al, 2010). This often leads to an inaccurate marking of SNc boundaries and a false pathological representation of dopamine degeneration (Langley et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Microstructural abnormalities of substantia nigra in Parkinson's disease: A neuromelanin sensitive MRI atlas based study

Safai

Prasad

Chougule

et al. 2019

Human Brain Mapping

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Microstructural changes associated with degeneration of dopaminergic neurons of the substantia nigra pars compacta (SNc) in Parkinson's disease (PD) have been studied using Diffusion Tensor Imaging (DTI). However, these studies show inconsistent results, mainly due to methodological variations in delineation of SNc. To mitigate this, our work aims to construct a probabilistic atlas of SNc based on a 3D Neuromelanin Sensitive MRI (NMS‐MRI) sequence and demonstrate its applicability to investigate microstructural changes on a large dataset of PD. Using manual segmentation and deformable registration we created a novel SNc atlas in the MNI space using NMS‐MRI sequences of 27 healthy controls (HC). We first quantitatively evaluated this atlas and then employed it to investigate the micro‐structural abnormalities in SNc using diffusion MRI from 133 patients with PD and 99 HCs. Our results demonstrated significant increase in diffusivity with no changes in anisotropy. In addition, we also observed an asymmetry of the diffusion metrics with a higher diffusivity and lower anisotropy in the left SNc than the right. Finally, a multivariate classifier based on SNc diffusion features could delineate patients with PD with an average accuracy of 71.7%. Overall, from this work we establish a normative baseline for the SNc region of interest using NMS‐MRI while the application on PD data emphasizes on the contribution of diffusivity measures rather than anisotropy of white matter in PD.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microstructural abnormalities of substantia nigra in Parkinson's disease: A neuromelanin sensitive MRI atlas based study

Safai

Prasad

Chougule

et al. 2019

Human Brain Mapping

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“…Earlier DTI studies on PD have been based on contrast obtained from T2 weighted images (Du et al, 2011;Langley et al, 2016;Prakash et al, 2012;Rolheiser et al, 2011;Schwarz et al, 2013;Vaillancourt et al, 2009). Comparative studies (Du et al, 2011;Langley et al, 2015)on contrast generating MR sequence for SNc have shown that T2w sequences and NMS-MRI sequences are both sensitive to different sub regions of SNc, although hypo-density observed on T2 images in PD could also indicate iron deposition apart from dopaminergic loss in the SNc, making it highly unreliable (Deng et al, 2018;Langley et al, 2016;Wypijewska et al, 2010). Recent work by Visser et al (Visser et al, 2016) has employed the FLASH sequence on 7T MRI to delineate the substantia nigra.…”

Section: Discussionmentioning

confidence: 99%

“…More importantly, the techniques employed for delineating the SNc may have a significant bearing on the variability in the observed results. For instance, in a conventional T2 weighted MRI, there is variability in the hypointensity associated with the SNc as a result of increased iron deposition, in addition to the reduction in neuromelanin content (Deng, Wang, Yang, Li, & Yu, 2018;Langley et al, 2016;Wypijewska et al, 2010).This often leads to an inaccurate marking of SNc boundaries, false pathological representation of dopamine degeneration and also a poor contrast of the SNc (Langley et al, 2016). Diffusion tractography based techniques to localize the SNc are more complicated and may depend upon the choice of diffusion MRI protocol and the fiber tracking algorithm.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Abnormalities of Substantia Nigra in Parkinson’s disease: A Neuromelanin Sensitive MRI Atlas Based Study

Safai

Prasad

Saini

et al. 2019

Preprint

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Microstructural changes associated with degeneration of dopaminergic neurons of the substantia nigra pars compacta (SNc) in Parkinson"s disease (PD) have been studied using Diffusion Tensor Imaging (DTI). However, these studies show inconsistent results, mainly due to methodological variations in delineation of SNc. To mitigate this, our work aims to construct a probabilistic atlas of SNc based on a Neuromelanin sensitive MRI (NMS-MRI) sequence and demonstrate its applicability to investigate microstructural changes on a large dataset of PD. Using manual segmentation and deformable registrations, we create a novel SNc atlas in the MNI space using NMS-MRI sequences of 27 healthy controls (HC). We employ this atlas to evaluate the diffusivity and anisotropy measures, derived from diffusion MRI in the SNc of 135 patients with PD and 99 HCs. Our observations of significantly increased diffusivity measures provide evidence of microstructural abnormalities in PD.However, no changes in the anisotropy were observed. Moreover, the asymmetry in abnormalities is prominent as the left SNc showed significant increase in diffusivity, and a reduction in FA when compared to the right SNc. Further the diffusivity and FA values also demonstrated a trend when correlated with the PD severity scores. Overall, from this work we establish a normative baseline for the SNc region of interest using NMS-MRI while the application on PD data emphasizes on the contribution of diffusivity measures rather than anisotropy of white matter in PD.

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“…We used the Newcastle-Ottawa Scale (NOS) criteria to assess the quality of all included studies [5]. Three studies showed high quality (≥8 points) [6], and all studies scored six points or more according to the NOS criteria, indicating the quality of all included studies was good [7]. Any disagreements on the quality assessment and data extraction would be resolved by consensus or consultation of a third party.…”

Section: Methodsmentioning

confidence: 99%

The relationship between time to surgery(TTS) after neoadjuvant chemotherapy (NAC)and survival in breast cancer patients: meta-analysis

Zheng

2020

Preprint

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PURPOSE: This meta-analysis aims to evaluate the impact of delaying surgery in operable breast tumor patients after neoadjuvant chemotherapy (NAC) on survival.METHODS: An electronic literature retrieval was conducted on PubMed/Medline and EMBASE((between January 2000 and June 2020).The primary end point was overall survival(OS),secondary end points included disease-free survival (DFS) or recurrence-free survival (RFS).The HR with 95% confidence intervals were calculated using a random-effects or fixed-effects model.RESULTS: The combined HR for OS was 1.52(95% CI 1.29-1.78; P = 0.000) by fixed-effects model.No statistically significant heterogeneity was found (P=0.114;I2=39.8%).The pooled HR for RFS/DFS was 1.47 (95%CI: 1.27- 1.71,I2=61.9%) by random-effects model, with significant heterogeneity.CONCLUSION: Our meta-analysis revealed a significant adverse association between longer TTS after NAC and more inferior OS and RFS/DFS in patients with breast cancer.Clinicians and patients should minimize surgical delay after NAC as much as possible.

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A meta-analysis of diffusion tensor imaging of substantia nigra in patients with Parkinson’s disease

Cited by 30 publications

References 32 publications

Microstructural abnormalities of substantia nigra in Parkinson's disease: A neuromelanin sensitive MRI atlas based study

Microstructural abnormalities of substantia nigra in Parkinson's disease: A neuromelanin sensitive MRI atlas based study

Microstructural Abnormalities of Substantia Nigra in Parkinson’s disease: A Neuromelanin Sensitive MRI Atlas Based Study

The relationship between time to surgery(TTS) after neoadjuvant chemotherapy (NAC)and survival in breast cancer patients: meta-analysis

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