title: Evaluation of Parkinson disease and Alzheimer disease with the use of neuromelanin MR imaging and (123)I-metaiodobenzylguanidine scintigraphy.
abstract: OBJECTIVE
  Progressive changes in the substantia nigra pars compacta and locus ceruleus of patients with Parkinson disease and Alzheimer disease visualized by neuromelanin MRI and cardiac postganglionic sympathetic nerve function on (123)I-metaiodobenzylguanidine scintigraphy have not been fully evaluated. We compared the diagnostic value of these modalities among patients with early Parkinson disease, late Parkinson disease, and Alzheimer disease.
  
  
  METHODS
  We compared contrast ratios of signal intensity in medial and lateral regions of the substantia nigra pars compacta and locus ceruleus with those of the tegmentum of the midbrain and the pons, respectively, by use of neuromelanin MRI in patients with early Parkinson disease (n = 13), late Parkinson disease (n = 31), Alzheimer disease (n = 6), and age-matched healthy control subjects (n = 20). We calculated heart-to-mediastinum ratios on (123)I-metaiodobenzylguanidine scintigrams after setting regions of interest on the left cardiac ventricle and upper mediastinum.
  
  
  RESULTS
  The signal intensity of the lateral substantia nigra pars compacta on neuromelanin MRI was significantly reduced in early and late Parkinson disease, and that of the medial substantia nigra pars compacta was gradually and stage-dependently reduced in Parkinson disease. The signal intensity of the locus ceruleus was obviously reduced in late Parkinson disease. Signal reduction was not significant in the substantia nigra pars compacta and locus ceruleus of patients with Alzheimer disease. The heart-to-mediastinum ratio on (123)I-metaiodobenzylguanidine scintigrams was stage-dependently reduced in Parkinson disease and normal in Alzheimer disease. The signal intensity ratios in substantia nigra pars compacta and locus ceruleus on neuromelanin MRI positively correlated with the heart-to-mediastinum ratio on (123)I-metaiodobenzylguanidine scintigrams.
  
  
  CONCLUSIONS
  Both neuromelanin MRI and (123)I-metaiodobenzylguanidine scintigraphy can help to evaluate disease progression in Parkinson disease and are useful for differentiating Parkinson disease from Alzheimer disease.
authors.affiliation: Division of Radiology, Department of Pathophysiological Therapeutic Science.
authors.forename: F
authors.initials: F
authors.lastname: Miyoshi
authors.forename: T
authors.initials: T
authors.lastname: Ogawa
authors.forename: S-i
authors.initials: SI
authors.lastname: Kitao
authors.forename: M
authors.initials: M
authors.lastname: Kitayama
authors.forename: Y
authors.initials: Y
authors.lastname: Shinohara
authors.forename: M
authors.initials: M
authors.lastname: Takasugi
authors.forename: S
authors.initials: S
authors.lastname: Fujii
authors.forename: T
authors.initials: T
authors.lastname: Kaminou
mesh_terms: D019797:3-Iodobenzylguanidine / Q000493:pharmacokinetics*; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000378:metabolism*; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008543:Melanins / Q000378:metabolism*; D008875:Middle Aged; D057054:Molecular Imaging / Q000379:methods; D010300:Parkinson Disease / Q000175:diagnosis* / Q000378:metabolism*; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution
chemical_list: D008543:Melanins; D019275:Radiopharmaceuticals; C014121:neuromelanin; D019797:3-Iodobenzylguanidine