title: Usefulness of rCBF analysis in diagnosing Parkinson's disease: supplemental role with MIBG myocardial scintigraphy.
abstract: (123)I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy is a useful tool for differentiating idiopathic Parkinson's disease (PD) from parkinsonism (PS) caused by other disorders. However, cardiac MIBG uptake is affected by various causes. Alternatively, hypoperfusion in the occipital lobe of PD is reported recently.
  
  
  OBJECTIVE
  The objective is to clarify the correlation between regional cerebral blood flow (rCBF) alteration and cardiac MIBG uptake in PD. In addition, we examined whether additional brain perfusion analysis improved the differential diagnostic ability for PD from PS when compared with MIBG scintigraphy alone.
  
  
  METHODS
  Forty-nine patients with PD (27 mild groups: Hoehn and Yahr stages I, II; 22 severe groups: Hoehn and Yahr stages III, IV) and 28 patients with PS participated. We compared absolute rCBF values between PD and PS. In addition, we determined correlation between MIBG parameters and each rCBF value. Finally, we compared the diagnostic ability for the differentiation of PD from PS between two diagnostic criteria, each MIBG index abnormality alone [heart-to-mediastinum ratio, H/M (E) < 1.9, H/E (D) < 1.7, washout rate > 40%] and each MIBG index abnormality or occipital lobe hypoperfusion (<36 ml/100 g per min).
  
  
  RESULTS
  Absolute rCBF value of occipital lobe was significantly lower in severe PD as compared with PS or mild PD. In the correlation analysis, rCBF of occipital lobe correlated positively with MIBG parameters (H/M). Regarding the diagnostic ability, sensitivity improved by accounting for occipital hypoperfusion as compared with MIBG indices alone. In contrast, neither specificity nor accuracy improved by adding occipital lobe analysis.
  
  
  CONCLUSIONS
  MIBG parameters (H/M) correlated positively with occipital hypoperfusion in PD. In the differential diagnosis between PD and PS, although its usefulness might be limited, analysis of rCBF in the occipital lobe added to (123)I-MIBG myocardial imaging can be recommended.
authors.affiliation: Department of Radiology, Miyazaki Medical College, 5200 Kihara, Kiyotake, Miyazaki-gun, Miyazaki 889-1692, Japan. snagama@med.miyazaki-u.ac.jp
authors.forename: Shigeki
authors.initials: S
authors.lastname: Nagamachi
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Wakamatsu
authors.forename: Shogo
authors.initials: S
authors.lastname: Kiyohara
authors.forename: Seigo
authors.initials: S
authors.lastname: Fujita
authors.forename: Shigemi
authors.initials: S
authors.lastname: Futami
authors.forename: Shozo
authors.initials: S
authors.lastname: Tamura
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Nakazato
authors.forename: Syuichi
authors.initials: S
authors.lastname: Yamashita
authors.forename: Hideo
authors.initials: H
authors.lastname: Arita
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Nishii
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kawai