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Is R2* a new MRI biomarker for the progression of Parkinson's disease? A longitudinal follow-up.

Ulla M, Bonny JM, Ouchchane L, Rieu I, Claise B, Durif F - PLoS ONE (2013)

Bottom Line: During the three-year evolution of PD, R2* increased in Substantia nigra (SN) (by 10.2% in pars compacta, p = 0.001, and 8.1% in pars reticulata, p = 0.013) and in the caudal putamen (11.4%, p = 0.011), without significant change in controls.Significant variation of R2* was longitudinally observed in the SN and caudal putamen of patients with PD evolving over a three-year period, emphasizing its interest as a biomarker of disease progression.Our results suggest that R2* MRI follow-up could be an interesting tool for individual assessment of neurodegeneration due to PD, and also be useful for testing the efficiency of disease-modifying treatments.

View Article: PubMed Central - PubMed

Affiliation: CHU Clermont-Ferrand, Service de Neurologie A, Clermont-Ferrand, France. mulla@chu-clermontferrand.fr

ABSTRACT

Purpose: To study changes of iron content in basal ganglia in Parkinson's disease (PD) through a three-year longitudinal follow-up of the effective transverse relaxation rate R2*, a validated MRI marker of brain iron content which can be rapidly measured under clinical conditions.

Methods: Twenty-seven PD patients and 26 controls were investigated by a first MRI (t0). Longitudinal analysis was conducted among the 18 controls and 14 PD patients who underwent a second MRI (t1) 3 years after. The imaging protocol consisted in 6 gradient echo images obtained at different echo-times for mapping R2*. Quantitative exploration of basal ganglia was performed by measuring the variation of R2* [R2*(t1) - R2*(t0)] in several regions of interest.

Results: During the three-year evolution of PD, R2* increased in Substantia nigra (SN) (by 10.2% in pars compacta, p = 0.001, and 8.1% in pars reticulata, p = 0.013) and in the caudal putamen (11.4%, p = 0.011), without significant change in controls. Furthermore, we showed a positive correlation between the variation of R2* and the worsening of motor symptoms of PD (p = 0.028).

Conclusion: Significant variation of R2* was longitudinally observed in the SN and caudal putamen of patients with PD evolving over a three-year period, emphasizing its interest as a biomarker of disease progression. Our results suggest that R2* MRI follow-up could be an interesting tool for individual assessment of neurodegeneration due to PD, and also be useful for testing the efficiency of disease-modifying treatments.

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ROI location in three different slices (A, B and C) in anatomic images.TR = 1100 ms, TE = 50 ms, field-of-view (FOV) = 280×280 mm, acquisition matrix = 256×256 1: Substantia nigra pars reticulata (SNr). 2: Substantia nigra pars compacta (SNc). 3: rostral putamen (rPut). 4: caudal putamen (cPut). 5: Globus Pallidus (GP). 6: gray matter (GM). 7: white matter (WM).
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pone-0057904-g001: ROI location in three different slices (A, B and C) in anatomic images.TR = 1100 ms, TE = 50 ms, field-of-view (FOV) = 280×280 mm, acquisition matrix = 256×256 1: Substantia nigra pars reticulata (SNr). 2: Substantia nigra pars compacta (SNc). 3: rostral putamen (rPut). 4: caudal putamen (cPut). 5: Globus Pallidus (GP). 6: gray matter (GM). 7: white matter (WM).

Mentions: Regions of interest (ROI) in which R2* was measured were defined manually on the anatomical images using ImageJ, a public domain software application (http://rsb.info.nih.gov/ij/). This approach was preferred to automatic segmentation because it is the only method able to subdivide SN into two parts (pars reticulata and pars compacta) [24]. The investigator responsible for ROI definition (M.U.) was unaware of subject group identification. The accurate position of each ROI was systematically controlled in the images obtained at the different TE and for the two MRI of the same subject based on relative distance of the ROI to the boundaries of the anatomical structure.The shape and size of the ROI were identical for a given structure in all subjects. Three BG structures were selected (Figure 1): the SN divided into two parts: pars reticulata and pars compacta (SNr and SNc respectively); according to recent data [5]; the putamen, also divided into two parts: rostral and caudal (rPut and cPut respectively); and the globus pallidus (GP). Grey matter (GM) and white matter (WM), both in the frontal lobe, were also studied. All ROI were placed bilaterally.


Is R2* a new MRI biomarker for the progression of Parkinson's disease? A longitudinal follow-up.

Ulla M, Bonny JM, Ouchchane L, Rieu I, Claise B, Durif F - PLoS ONE (2013)

ROI location in three different slices (A, B and C) in anatomic images.TR = 1100 ms, TE = 50 ms, field-of-view (FOV) = 280×280 mm, acquisition matrix = 256×256 1: Substantia nigra pars reticulata (SNr). 2: Substantia nigra pars compacta (SNc). 3: rostral putamen (rPut). 4: caudal putamen (cPut). 5: Globus Pallidus (GP). 6: gray matter (GM). 7: white matter (WM).
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585727&req=5

pone-0057904-g001: ROI location in three different slices (A, B and C) in anatomic images.TR = 1100 ms, TE = 50 ms, field-of-view (FOV) = 280×280 mm, acquisition matrix = 256×256 1: Substantia nigra pars reticulata (SNr). 2: Substantia nigra pars compacta (SNc). 3: rostral putamen (rPut). 4: caudal putamen (cPut). 5: Globus Pallidus (GP). 6: gray matter (GM). 7: white matter (WM).
Mentions: Regions of interest (ROI) in which R2* was measured were defined manually on the anatomical images using ImageJ, a public domain software application (http://rsb.info.nih.gov/ij/). This approach was preferred to automatic segmentation because it is the only method able to subdivide SN into two parts (pars reticulata and pars compacta) [24]. The investigator responsible for ROI definition (M.U.) was unaware of subject group identification. The accurate position of each ROI was systematically controlled in the images obtained at the different TE and for the two MRI of the same subject based on relative distance of the ROI to the boundaries of the anatomical structure.The shape and size of the ROI were identical for a given structure in all subjects. Three BG structures were selected (Figure 1): the SN divided into two parts: pars reticulata and pars compacta (SNr and SNc respectively); according to recent data [5]; the putamen, also divided into two parts: rostral and caudal (rPut and cPut respectively); and the globus pallidus (GP). Grey matter (GM) and white matter (WM), both in the frontal lobe, were also studied. All ROI were placed bilaterally.

Bottom Line: During the three-year evolution of PD, R2* increased in Substantia nigra (SN) (by 10.2% in pars compacta, p = 0.001, and 8.1% in pars reticulata, p = 0.013) and in the caudal putamen (11.4%, p = 0.011), without significant change in controls.Significant variation of R2* was longitudinally observed in the SN and caudal putamen of patients with PD evolving over a three-year period, emphasizing its interest as a biomarker of disease progression.Our results suggest that R2* MRI follow-up could be an interesting tool for individual assessment of neurodegeneration due to PD, and also be useful for testing the efficiency of disease-modifying treatments.

View Article: PubMed Central - PubMed

Affiliation: CHU Clermont-Ferrand, Service de Neurologie A, Clermont-Ferrand, France. mulla@chu-clermontferrand.fr

ABSTRACT

Purpose: To study changes of iron content in basal ganglia in Parkinson's disease (PD) through a three-year longitudinal follow-up of the effective transverse relaxation rate R2*, a validated MRI marker of brain iron content which can be rapidly measured under clinical conditions.

Methods: Twenty-seven PD patients and 26 controls were investigated by a first MRI (t0). Longitudinal analysis was conducted among the 18 controls and 14 PD patients who underwent a second MRI (t1) 3 years after. The imaging protocol consisted in 6 gradient echo images obtained at different echo-times for mapping R2*. Quantitative exploration of basal ganglia was performed by measuring the variation of R2* [R2*(t1) - R2*(t0)] in several regions of interest.

Results: During the three-year evolution of PD, R2* increased in Substantia nigra (SN) (by 10.2% in pars compacta, p = 0.001, and 8.1% in pars reticulata, p = 0.013) and in the caudal putamen (11.4%, p = 0.011), without significant change in controls. Furthermore, we showed a positive correlation between the variation of R2* and the worsening of motor symptoms of PD (p = 0.028).

Conclusion: Significant variation of R2* was longitudinally observed in the SN and caudal putamen of patients with PD evolving over a three-year period, emphasizing its interest as a biomarker of disease progression. Our results suggest that R2* MRI follow-up could be an interesting tool for individual assessment of neurodegeneration due to PD, and also be useful for testing the efficiency of disease-modifying treatments.

Show MeSH
Related in: MedlinePlus