title: Olfactory function combined with morphology distinguishes Parkinson's disease.
abstract: OBJECTIVE
  This study aimed to examine whether the volume of the olfactory bulbs and tracts (OB & T) on magnetic resonance imaging (MRI) is useful for differentiating Parkinson's disease (PD) from PD-related disorders.
  
  
  METHODS
  The study group comprised 13 patients with PD, 11 with multiple system atrophy (MSA), five with progressive supranuclear palsy, and five with corticobasal degeneration (PSP/CBD). All patients were evaluated using the odor stick identification test for Japanese (OSIT-J), (123)I-meta-iodobenzylguanidine (MIBG) scintigraphy, and brain MRI. OB & T areas on 1-mm-thick coronal images were measured and summed for volumes. We examined relationships between olfactory function and volume, and cardiovascular dysautonomia. We defined the cut-off values for OSIT-J score or MIBG uptake and OB & T volume to discriminate PD from PD-related disorders and calculated the proportional rate of PD in four categorized groups.
  
  
  RESULTS
  OB & T volume was smaller in PD than in MSA or PSP/CBD (p < 0.05 each). The cut-off for detecting PD patients was OSIT-J score <8, heart/mediastinum ratio <1.6, and OB & T volume <270 mm(3). In the group with OSIT-J score <8 and OB & T volume <270 mm(3), the proportion of PD patients among all patients with PD-related disorders was 91%. The rate of probable PD gradually increased as OSIT-J score and OB & T volume decreased (p < 0.001).
  
  
  CONCLUSIONS
  Although preliminary, these data obtained from a combined morphological and functional evaluation of OB or cardiovascular dysautonomia could be useful for further differential of PD and other PD-related disorders.
authors.affiliation: Department of Neurology, The Jikei University School of Medicine, Tokyo, Japan; Department of Neurology, Tokyo Metropolitan Geriatric Hospital, Tokyo, Japan. Electronic address: renpeis@gmail.com.
authors.forename: Renpei
authors.initials: R
authors.lastname: Sengoku
authors.affiliation: Department of Radiology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Matsushima
authors.affiliation: Department of Neurology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Bono
authors.affiliation: Department of Neurology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sakuta
authors.affiliation: Department of Neurology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Mikihiro
authors.initials: M
authors.lastname: Yamazaki
authors.affiliation: Department of Neurology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Miyagawa
authors.affiliation: Department of Neurology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Teppei
authors.initials: T
authors.lastname: Komatsu
authors.affiliation: Department of Neurology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Mitsumura
authors.affiliation: Department of Neurology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Kono
authors.affiliation: Department of Neurology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kamiyama
authors.affiliation: Department of Radiology, Tokyo Metropolitan Geriatric Hospital, Tokyo, Japan.
authors.forename: Kimiteru
authors.initials: K
authors.lastname: Ito
authors.affiliation: The Jikei University School of Nursing, Tokyo, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Mochio
authors.affiliation: Department of Neurology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Iguchi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009812:Odorants; D000857:Olfaction Disorders / Q000175:diagnosis* / Q000503:physiopathology; D009830:Olfactory Bulb / Q000473:pathology* / Q000502:physiology*; D009929:Organ Size; D010300:Parkinson Disease / Q000175:diagnosis* / Q000503:physiopathology
keywords: (123)I-MIBG scintigraphy; MRI; OB; OSIT-J; OT; Olfactory bulb and tract volume; Olfactory dysfunction; Parkinsonism; UPDRS; magnetic resonance imaging; meta-iodobenzylguanidine ((123)I-MIBG) scintigraphy; meta-iodobenzylguanidine scintigraphy; odor stick identification test for Japanese; olfactory bulb; olfactory tract; unified Parkinson's Disease Rating Scale