Evaluation of MR signal index for the assessment of occupational manganese exposure of welders by measurement of local proton T1 relaxation time

Choi, Dae Seob; Kim, Eun A; Cheong, Hae-Kwan; Khang, Hyun Soo; Ryoo, Jae Wook; Cho, Jae Min; Sakong, Joon; Park, Injeong

doi:10.1016/j.neuro.2006.05.020

Cited by 36 publications

(42 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Discussioncontrasting

confidence: 74%

“…The average blood Mn level, however, was considerably lower compared to other studies (e.g., blood Mn>14.2 ng/mL, (Choi et al, 2007), but this may have been due to blood collection on the day of the study visit rather than directly after welding. In addition, the PI in our welders (mean PI =109) also was lower compared to several other studies (PI> 112) (Choi et al, 2007, Chang et al, 2009), suggesting that the welders in this study probably had overall lower Mn exposure. Many welders in our study worked only intermittently during the 90-day exposure period (data not shown), and this likely was a factor in keeping blood Mn levels and MRI indices (PI and R1 values) low relative to other studies (Dorman et al, 2006, Chang et al, 2009).…”

Section: Discussioncontrasting

confidence: 74%

“…In addition, past studies (Dietz et al, 2001, Choi et al, 2007, Chang et al, 2010, Baker et al, 2015a, Lee et al, 2015) have interrogated the effects of low-level Mn exposure that typically does not correspond to a clinical phenotype. Previous longitudinal studies in welders found preserved motor function (i.e., using the grooved pegboard and UPDRS-III scores) in welders over short time-frames (90 days; Baker et al, 2015b) but decreased targeted functional outcomes over long time periods (~6 years; Ellingsen et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Longitudinal T1 relaxation rate (R1) captures changes in short-term Mn exposure in welders

et al. 2016

View full text Add to dashboard Cite

Objectives We demonstrated recently that the T1 relaxation rate (R1) captured short-term Mn exposure in welders with chronic, relatively low exposure levels in a cross-sectional study. In the current study, we used a longitudinal design to examine whether R1 values reflect the short-term dynamics of Mn exposure. Methods Twenty-nine welders were evaluated at baseline and 12 months. Occupational questionnaires estimated short-term welding exposure using welding hours in the 90 days prior to each study visit (HrsW90). In addition, blood Mn levels, the pallidal index (PI; globus pallidus T1-weighted intensity (T1WI)/frontal white matter T1WI), and R1 values in brain regions of interest (ROIs) were determined as Mn biomarkers at each visit. Associations between changes in estimated welding exposure and changes in purported Mn biomarkers were assessed by Spearman’s correlations with adjustment for age and baseline R1, HrsW90, and blood Mn values. Results Changes in welding hours (HrsW90: the short-term welding exposure estimate), was associated significantly with changes in R1 values in the putamen (r=0.541, p=0.005), caudate (R=0.453, p=0.023), globus pallidus (R=0.430, p=0.032), amygdala (R=0.461, p=0.020), and hippocampus (R=0.447, p=0.025), but not with changes in blood Mn levels or the PI. Discussion Changes in R1 values correlated with changes in the short-term welding exposure estimate, but not with more traditional measures of Mn exposure (blood Mn levels or PI). These results suggest that R1 may serve as a useful marker to capture the short-term dynamics in Mn brain accumulation related to welding exposure.

show abstract

Section: Discussioncontrasting

confidence: 74%

Section: Discussioncontrasting

confidence: 74%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Longitudinal T1 relaxation rate (R1) captures changes in short-term Mn exposure in welders

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Indicators weighed T1 and pI in MRI still continue to be used as a non-invasive and sensitive biomarker for assessing exposure to manganese in workers 47 . The usefulness of MRI in studies also is approved 11, [63][64][65][66][67] . Only in one article of uric acid, urine is investiagted as a biomarker of manganese 52 .…”

Section: Discussionmentioning

confidence: 99%

Biomarkers of Occupational Manganese Toxicity

Bahrami¹,

Jafari²,

Arslanoğlu³

et al. 2015

Biosci., Biotech. Res. Asia

View full text Add to dashboard Cite

show abstract

“…In 2007, Choi et al found in human MRI studies that the blood Mn level correlated only with the T1 relaxation time, but not with the PI, and that the T1 correlation with PI was only present at higher levels of the PI. 63 Similarly, Sen et al reported group differences in T1 relaxation times and normalized T1w signal intensities (not using a ratio) in several brain regions between welders and non-exposed workers in the US, yet saw no differences in the PI. 21 Moreover, they found no correlations of the PI with fine motor measures, yet these correlations were present for the normalized signal intensities.…”

Section: Relaxometry To Quantify Brain Mnmentioning

confidence: 95%

Imaging Modalities for Manganese Toxicity

Dydak¹,

Criswell²

2014

Manganese in Health and Disease

View full text Add to dashboard Cite

Rapidly advancing imaging technology has been essential to the study of manganese (Mn) toxicity in vivo. Over the past few decades, imaging techniques have been effectively utilized as markers of Mn exposure and to investigate the biological effects of Mn neurotoxicity. This chapter will review several of the imaging modalities that have made an impact in Mn neurotoxicity research. The scope of this chapter will include discussions of magnetic resonance imaging (MRI), including magnetic resonance spectroscopy (MRS), diffusion weighted imaging (DWI), and functional MRI (fMRI), as well as positron emission tomography (PET), single photon emission computed tomography (SPECT), and X-ray fluorescence imaging. For each modality, the basic principle of the imaging technique will be briefly described to facilitate proper data interpretation and understanding of limitations. This will be followed by a discussion on the main research findings using that modality, and how they have shaped our understanding of Mn toxicity.

show abstract

Evaluation of MR signal index for the assessment of occupational manganese exposure of welders by measurement of local proton T1 relaxation time

Cited by 36 publications

References 11 publications

Longitudinal T1 relaxation rate (R1) captures changes in short-term Mn exposure in welders

Longitudinal T1 relaxation rate (R1) captures changes in short-term Mn exposure in welders

Biomarkers of Occupational Manganese Toxicity

Imaging Modalities for Manganese Toxicity

Contact Info

Product

Resources

About