Direct Visualization of Parkinson's Disease by In Vivo Human Brain Imaging Using 7.0T Magnetic Resonance Imaging

Neuroscience Research Institute, Gachon University of Medicine and Science, Namdong-gu, Incheon, South Korea.
Movement Disorders (Impact Factor: 5.68). 03/2011; 26(4):713-8. DOI: 10.1002/mds.23465
Source: PubMed


Parkinson's disease (PD) is a neurodegenerative disorder resulting from progressive loss of dopaminergic neurons in the substantia nigra (SN) pars compacta. Therefore, imaging of the SN has been regarded to hold greatest potential for use in the diagnosis of PD. At the 7.0T magnetic resonance imaging (MRI), it is now possible to delineate clearly the shapes and boundaries of the SN. We scanned eight early and two advanced PD patients, along with nine age-matched control subjects, using a 7.0T MRI in an attempt to directly visualize the SN and quantify the differences in shape and boundaries of SN between PD subjects in comparison with the normal control subjects. In the normal controls, the boundaries between the SN and crus cerebri appear smooth, and clean "arch" shapes that stretch ventrally from posterior to anterior. In contrast, these smooth and clean arch-like boundaries were lost in PD subjects. The measured correlation analyses show that, in PD patients, there is age-dependent correlation and substantially stronger UPDRS motor score-dependent correlation. These results suggest that, by using 7.0T MRI, it appears possible to use these visible and distinctive changes in morphology as a diagnostic marker of PD.

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Available from: Se-Hong Oh, Jan 02, 2015
    • "Multiple studies have shown an increase in R 2 in the SN for PD groups over controls (German et al., 1992; Gorell et al., 1995; Peran et al., 2007, 2010) while another study found no change in R 2 between early stage PD, late stage PD, and control groups (Aquino et al., 2014). Other studies using SWI have shown that the concentration of brain iron correlates with unified Parkinson's disease rating scale (UPDRS) score (Zhang et al., 2010) or differentiated PD from atypical Parkinsonian disorders (Gupta et al., 2010); also recent work has used T 2 -weighted methods at high magnetic field strengths (7 T) to image nigrosome 1 within the SN (Blazejewska et al., 2013; Cho et al., 2011; Schwarz et al., 2014). "
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    ABSTRACT: We characterize the contrast behavior of substantia nigra (SN) in both magnetization transfer (MT) imaging, which is believed to be sensitive to neuromelanin (NM), and susceptibility weighted imaging (SWI). Images were acquired with a MT prepared dual echo gradient echo sequence. The first echo was taken as the MT contrast image and the second was used to generate the SWI image. SN volumes were segmented from these two types of images using a thresholding method. The spatial and signal characteristics of the extracted SWI and MT volumes were compared. Both images showed the presence of SN but the volumes of the SN identified in the two are spatially incongruent. The MT volume was more caudal than the SWI volume and with only a 12% overlap between the two volumes. Considering the SN volumes in each hemisphere separately, the average distances between the centers of mass of the volumes from the two types images are 5.1±1.1mm and 4.1±1.2mm, respectively. The frequency offsets (homodyne filtered phase/echo time) for the volumes derived from MT (NM) images and SWI images are 0.09±0.32 radians/s and -1.12±0.57 radians/s (p<0.0001), respectively. The MT contrasts for the two volumes are 0.16±0.02 and 0.10±0.03 (p<0.001), respectively. Our results indicate that the two contrasts are sensitive to different portions of the SN, with MT seeing the more caudal portion of the SN than SWI, likely due to variations of NM and iron content in the SN. Despite the small overlap, these regions are complementary. Our results provide a new understanding of the contrast behavior of the SN in the two imaging approaches commonly used to image it and indicate that using both may yield a more comprehensive visualization of the SN. Copyright © 2015. Published by Elsevier Inc.
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    • "Significantly reduced volumes of the whole SN in PD have also been reported at 3T [Menke et al., 2009], but with limited specificity for diagnostic potential. Recently, two promising studies carried out at 7T field strength detected nigral boundary and volumetric differences in small samples of PD patients and controls [Cho et al., 2011; Kwon et al., 2012], suggesting that to date clinically elusive ultra-high field structural MRI that enables excellent visualization of the SN may be able to provide a diagnostic marker for PD in the future. "
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    ABSTRACT: Previous imaging studies that investigated morphometric group differences of subcortical regions outside the substantia nigra between non-demented Parkinson's patients and controls either did not find any significant differences, or reported contradictory results. Here, we performed a comprehensive morphometric analysis of 20 cognitively normal, early-stage PD patients and 19 matched control subjects. In addition to relatively standard analyses of whole-brain grey matter volume and overall regional volumes, we examined subtle localized surface shape differences in striatal and limbic grey matter structures and tested their utility as a diagnostic marker. Voxel-based morphometry and volumetric comparisons did not reveal significant group differences. Shape analysis, on the other hand, demonstrated significant between-group shape differences for the right pallidum. Careful diffusion tractography analysis showed that the affected parts of the pallidum are connected subcortically with the subthalamic nucleus, the pedunculopontine nucleus, and the thalamus and cortically with the frontal lobe. Additionally, microstructural measurements along these pathways, but not along other pallidal connections, were significantly different between the two groups. Vertex-wise linear discriminant analysis, however, revealed limited accuracy of pallidal shape for the discrimination between patients and controls. We conclude that localized disease-related changes in the right pallidum in early Parkinson's disease, undetectable using standard voxel-based morphometry or volumetry, are evident using sensitive shape analysis. However, the subtle nature of these changes makes it unlikely that shape analysis alone will be useful for early diagnosis. Hum Brain Mapp, 2013. © 2013 Wiley-Periodicals, Inc.
    Full-text · Article · Apr 2014 · Human Brain Mapping
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    • "This was followed by Gorell et al. in 1995 who utilized T2 and T2* imaging of the substantia nigra and showed a separation between those with PD from control participants by using a change in relaxation time constants as a surrogate for increased iron in PD [3]. The focus on T2*or its reciprocal R2*has remained an important aspect of nigral imaging protocols, and an excellent demonstration of macroscopic nigral changes attributable to iron was shown by Cho et al. in their 7 Tesla (T) imaging study [4]. One crucial assumption about “iron” based imaging is that the methods reflect upon non-heme iron as opposed to heme-iron, and that while the small pool of free labile iron may be pathogenic - imaging methods are presently sensitive to the more prevalent bound iron that is stored as ferritin or neuromelanin [5]. "
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    ABSTRACT: Recent developments in brain imaging methods are on the verge of changing the evaluation of people with Parkinson's disease (PD). This includes an assortment of techniques ranging from diffusion tensor imaging (DTI) to iron-sensitive methods such as T2 (*), as well as adiabatic methods R1ρ and R2ρ, resting-state functional MRI, and magnetic resonance spectroscopy (MRS). Using a multi-modality approach that ascertains different aspects of the pathophysiology or pathology of PD, it may be possible to better characterize disease phenotypes as well as provide a surrogate of disease and a potential means to track disease progression.
    Full-text · Article · Mar 2013
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