Reduction of Neuromelanin-Positive Nigral Volume in Patients with MSA, PSP and CBD

Abstract

Objective Diseases presenting extrapyramidal symptoms are accompanied by nigral cell loss. In the previous study, we demonstrated the reduction of the neuromelanin-positive volume of substantia nigra (SN) pars compacta (SNc) in patients with Parkinson's disease (PD) using 3-Tesla MRI. In the present study we investigated the neuromelanin-positive SNc volume in patients with the other parkinsonian disorders including multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) and compared the results with those with PD, spinocerebellar ataxia (SCA) and controls. Patients and Methods Axial T1-weighted (T1W) images were obtained with a 3-Tesla MRI scanner. The border of the neuromelanin-positive region of the SNc was traced manually on these images with a pentablet pointing device and the SNc volume was calculated. The SNc volumes of 28 patients with MSA, 11 patients with PSP and 10 patients with CBD were compared with those of 80 patients with PD, 9 patients with SCA and 54 patients who had suffered mild acute ischemic stroke as controls. The mean volumes for the left and right SN were used for statistical analyses. Results The volumes of the neuromelanin-positive SNc region in patients with MSA, PSP and CBD, but not SCA were reduced to the same extent as PD patients compared with controls. Conclusion Reduced volume of the neuromelanin-positive SNc region of patients with MSA, PSP and CBD was detected by neuromelanin MR imaging. Volumetric evaluation of neuromelanin MR imaging may provide a biomarker of nigral degeneration in patients with MSA, PSP and CBD as in patients with PD.

Neuromelanin Magnetic Resonance Imaging in Parkinson's Disease and Multiple System Atrophy

“…More recently, Kashihara et al [18] reported that reduced volume of neuromelanin-positive SNc was found in patients with MSA using neuromelanin imaging based on the signal decrease of SNc compared with that of surrounding brain tissue. However, no report in the relevant literature has described neuromelanin imaging regarding the LC in MSA, although MSA patients exhibit autonomic symptoms and neuronal loss and gliosis in the SNc and LC (more predominantly in the latter) [27].…”

“…Neuronal loss and gliosis occur in the SNc of MSA patients, but in a more delayed fashion compared to that in PD [3], which might account for the discrepant results from a decreased contrast ratio of the SNc in MSA in a previous study [18]. In the early stage of PD, the contrast ratio of SNc mi decreased more markedly than that of SNc me .…”

“…Second, we used contrast ratios of the SNc and LC to evaluate the loss of neuromelanin-containing neurons, as originally reported by Sasaki et al [15]. More recently, Kashihara et al [16,18] estimated nigral volume, and Schwarz et al [17] used the T1 hyperintensity area in the SNc for the evaluation of neuromelanin-containing neuron loss, assuming that volume or area measurement is a more sensitive indicator for neurodegeneration than the contrast ratio method. However, 2D neuromelanin imaging with a thick slice and slice gap is inappropriate to evaluate the volume or area of SNs.…”

“…Recent reports suggest that advanced MRI techniques such as diffusion-weighted imaging [10,11], magnetic resonance spectroscopy [12,13], and susceptibility weighted imaging are useful in the differential diagnosis of parkinsonian disorders [14]. More recently, reports have described that the neuromelanin signal is decreased in the LC and SNc of PD patients [15,16,17] and in the SNc in patients with MSA, corticobasal degeneration, and progressive supranuclear palsy [18]. We attempted to correlate neurological and radiological findings with neuromelanin MRI in patients with PD and MSA, and thereby reveal the diagnostic significance of this method in the differentiation of MSA from PD.…”

Simultaneous imaging of locus coeruleus and substantia nigra with a quantitative neuromelanin MRI approach

“…Sasaki and colleagues reported that both LC and SN can be imaged by using a T 1 -weighted turbo spin echo (TSE) sequence [8]. Other groups have also successfully applied similar spin echo techniques to study the LC and/ or SN [4,5,[9][10][11][12]. The size of the LC (a rod-shaped structure approximately 2-mm wide and 15-mm long) [13,14] dictates the need for an acquisition with high spatial resolution.…”