title: Combined R2* and diffusion tensor imaging changes in the substantia nigra in Parkinson's disease.
abstract: Recent magnetic resonance imaging studies suggest an increased transverse relaxation rate and reduced diffusion tensor imaging fractional anisotropy values in the substantia nigra in Parkinson's disease. The transverse relaxation rate and fractional anisotropy changes may reflect different aspects of Parkinson's disease-related pathological processes (ie, tissue iron deposition and microstructure disorganization). This study investigated the combined changes of transverse relaxation rate and fractional anisotropy in the substantia nigra in Parkinson's disease. High-resolution magnetic resonance imaging (T2-weighted, T2*, and diffusion tensor imaging) were obtained from 16 Parkinson's disease patients and 16 controls. Bilateral substantia nigras were delineated manually on T2-weighted images and coregistered to transverse relaxation rate and fractional anisotropy maps. The mean transverse relaxation rate and fractional anisotropy values in each substantia nigra were then calculated and compared between Parkinson's disease subjects and controls. Logistic regression, followed by receiver operating characteristic curve analysis, was employed to investigate the sensitivity and specificity of the combined measures for differentiating Parkinson's disease subjects from controls. Compared with controls, Parkinson's disease subjects demonstrated increased transverse relaxation rate (P<.0001) and reduced fractional anisotropy (P=.0365) in the substantia nigra. There was no significant correlation between transverse relaxation rate and fractional anisotropy values. Logistic regression analyses indicated that the combined use of transverse relaxation rate and fractional anisotropy values provides excellent discrimination between Parkinson's disease subjects and controls (c-statistic=0.996) compared with transverse relaxation rate (c-statistic=0.930) or fractional anisotropy (c-statistic=0.742) alone. This study shows that the combined use of transverse relaxation rate and fractional anisotropy measures in the substantia nigra of Parkinson's disease enhances sensitivity and specificity in differentiating Parkinson's disease from controls. Further studies are warranted to evaluate the pathophysiological correlations of these magnetic resonance imaging measurements and their effectiveness in assisting in diagnosing Parkinson's disease and following its progression.
authors: Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033-0850, USA.
authors: Guangwei
authors: G
authors: Du
authors: Mechelle M
authors: MM
authors: Lewis
authors: Martin
authors: M
authors: Styner
authors: Michele L
authors: ML
authors: Shaffer
authors: Suman
authors: S
authors: Sen
authors: Qing X
authors: QX
authors: Yang
authors: Xuemei
authors: X
authors: Huang
references: AJNR Am J Neuroradiol. 2002 Nov-Dec;23(10):1747-56
references: 12427635
references: Mov Disord. 1996 May;11(3):243-9
references: 8723139
references: Neurology. 2008 Apr 15;70(16 Pt 2):1411-7
references: 18172063
references: Brain. 2010 Nov;133(11):3423-33
references: 20736190
references: Neurology. 1995 Jun;45(6):1138-43
references: 7783878
references: Radiology. 1999 Mar;210(3):759-67
references: 10207479
references: J Neurol Neurosurg Psychiatry. 2004 Mar;75(3):481-4
references: 14966170
references: J Neurol Neurosurg Psychiatry. 2007 Dec;78(12):1383-6
references: 17615165
references: Neuron. 2006 Sep 7;51(5):527-39
references: 16950152
references: Ann Neurol. 1992;32 Suppl:S125-7
references: 1510370
references: Neurobiol Dis. 2007 Jun;26(3):590-6
references: 17428671
references: J Neural Transm. 1988;74(3):199-205
references: 3210014
references: J Neuropathol Exp Neurol. 1968 Jan;27(1):1-14
references: 5656584
references: Neurobiol Aging. 2012 Jan;33(1):35-42
references: 20359780
references: J Magn Reson B. 1996 Jun;111(3):209-19
references: 8661285
references: J Neurochem. 1989 Jun;52(6):1830-6
references: 2723638
references: Med Image Anal. 2001 Jun;5(2):143-56
references: 11516708
references: Neurology. 2009 Apr 21;72(16):1378-84
references: 19129507
references: Neuroimage. 2010 Jun;51(2):512-20
references: 20211271
references: Brain. 1991 Oct;114 ( Pt 5):2283-301
references: 1933245
references: Neuroimage. 2004;23 Suppl 1:S208-19
references: 15501092
references: Magn Reson Med. 1994 Sep;32(3):335-41
references: 7984066
references: Neuroimage. 2006 Jul 1;31(3):1116-28
references: 16545965
references: Magn Reson Imaging. 2005 Jan;23(1):1-25
references: 15733784