Keywords:
Pathology, Image verification, Dementia, Technology assessment, Statistics, Experimental investigations, Nuclear medicine conventional, MR, Nuclear medicine, Neuroradiology brain, CNS
Authors:
F. Miyoshi, S. Kitao, M. Takasugi, Y. Shinohara, Y. Kanasaki, S. Fujii, T. Kaminou, T. Ogawa; Yonago/JP
DOI:
10.1594/ecr2013/C-1200
Purpose
Neuromelanin is a dark pigment that locates within certain catecholamine neurons of the human brain,
such as the dopaminergic neurons of the substantia nigra pars compacta (SNc) and the noradrenergic neurons of the locus ceruleus (LC).1 It is thought to be formed as a by-product of the catecholamine metabolism cascade via enzymatic and/or oxidative polymerization.1,2 Parkinson’s disease (PD) is characterized by the progressive loss of dopaminergic neurons that contain neuromelanin in the SNc and of noradrenergic neurons in the LC.
Several pathological studies have shown the selective loss of ventral intermediate and lateral cell groups of the SNc in PD.3,4,5 Noradrenergic neurons are also lost in the LC of patients with Alzheimer’s disease (AD).6
Sasaki et al.
reported that neuromelanin magnetic resonance imaging (NmMRI) could visualize decreased signal intensity in regions that reflect the loss of neurons containing neuromelanin.7,8 They also reported that the signal intensity in the SNc and LC was greatly reduced on NmMR images from patients with PD.
Several investigators subsequently reported that NmMRI can show a reduction in the contrast ratio and volume of the SNc.9,10
The physiological analogue of noradrenaline,123I-metaiodobenzylguanidine (MIBG),
traces uptake and transports both in noradrenaline presynaptic sympathetic nerve terminals and in subsequent vesicular storage.11 Postganglionic presynaptic cardiac sympathetic nerve endings can be non-invasively assessed by MIBG scintigraphy as a reduction of MIBG uptake indicates postganglionic sympathetic dysfunction.
Cardiac MIBG uptake is reduced in patients with Lewy body diseases such as PD,
as well as dementia with Lewy bodies,
and MIBG scintigraphy can also help to differentiate PD from other types of parkinsonism.12,13
PD in its early stages can easily be mistaken for any number of disorders.
AD can also be mistaken for PD.14 However,
the prognosis is completely different among these disorders,
and the choice of treatment strategy becomes very important.
Because early differentiation of PD and other neurodegenerative parkinsonism is crucial,
there is an important need to improve the diagnostic accuracy.
The purpose of this study was to determine the usefulness of these modalities for the diagnosis of PD and AD by analyzing changes in signal intensity in the SNc and LC and MIBG uptake in the left cardiac ventricle,
and examined the results for correlations between NmMRI and MIBG scintigraphy findings.