title: Subregional Pattern of Striatal Dopamine Transporter Loss on 18F FP-CIT Positron Emission Tomography in Patients With Pure Akinesia With Gait Freezing.
abstract: OBJECTIVE
  Pure akinesia with gait freezing (PAGF) is a clinical syndrome characterized by freezing of gait, handwriting, and speech without abnormal eye movement or cognitive impairment. Several studies have suggested that PAGF may be a variant of progressive supranuclear palsy (PSP). However, the characteristics of striatal dopamine transporter loss in PAGF are unknown.
  
  
  OBJECTIVE
  To investigate the subregional pattern of striatal dopamine transporter loss in patients with PAGF in comparison with patients with PSP and those with Parkinson disease (PD).
  
  
  METHODS
  This retrospective case-control study included 15 patients with PAGF, 27 with PD, 20 with PSP, and 11 healthy controls who underwent F-18-fluorinated-N-3-fluoropropyl-2β-carboxymethoxy-3β-(4-iodophenyl)-nortropane (18F FP-CIT) positron emission tomography between September 1, 2008, and July 31, 2014. The positron emission tomographic images were analyzed with 12 striatal subregional and 1 occipital volume-of-interest templates. The specific to nonspecific binding ratio (SNBR) and intersubregional ratio (ISR) in patients with PAGF were compared with those in patients with PD and those with PSP.
  
  
  METHODS
  Comparisons of SNBRs of striatal subregions and ISR among patients with PAGF, PD, and PSP and healthy controls.
  
  
  RESULTS
  The mean (SD) SNBRs (1.4 [0.7]) of the whole striatum in the 15 patients with PAGF (mean [SD] age, 71.4 [6.6] years; 7 men and 8 women) were similar to those in the 20 patients (mean [SD] age, 70.6 [4.5] years; 11 men and 9 women) with PSP (1.5 [0.5]) but significantly lower than those in the 27 patients (mean [SD] age, 67.7 [5.3] years; 10 men and 17 women) with PD (3.0 [1.3]). The mean (SD) SNBRs of the caudate nuclei in patients with PAGF (1.3 [0.9]) were significantly lower than those in patients with PD (3.5 [1.5]; P < .001) but slightly higher than those in patients with PSP (1.2 [0.5]). The mean [SD] anterior caudate to ventral striatum ISRs in patients with PAGF (0.5 [0.3]) were similar to those in patients with PSP (0.4 [0.2]) but not in patients with PD (1.0 [0.2]). The mean (SD) posterior to anterior putamen ISRs in patients with PAGF (0.4 [0.2]) were similar to those in patients with PD (0.5 [0.2]) and those with PSP (0.4 [0.2]).
  
  
  CONCLUSIONS
  On 18F FP-CIT positron emission tomography, patients with PAGF show a pattern of preferential dopaminergic loss similar to that seen in patients with PSP. These results suggest a similar distribution of regional neuronal loss in the substantia nigra pars compacta between PAGF and PSP. This finding may be one of the pathophysiological results suggesting that PAGF is a phenotypic variant of PSP.
authors.affiliation: Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Sangwon
authors.initials: S
authors.lastname: Han
authors.affiliation: Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Minyoung
authors.initials: M
authors.lastname: Oh
authors.affiliation: Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Jungsu S
authors.initials: JS
authors.lastname: Oh
authors.affiliation: Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Sang Ju
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Seung Jun
authors.initials: SJ
authors.lastname: Oh
authors.affiliation: Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Sun Ju
authors.initials: SJ
authors.lastname: Chung
authors.affiliation: Department of Neurology, Inje University Ilsan-Paik Hospital, Goyang, Republic of Korea.
authors.forename: Hee Kyung
authors.initials: HK
authors.lastname: Park
authors.affiliation: Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Jae Seung
authors.initials: JS
authors.lastname: Kim
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D003342:Corpus Striatum / Q000000981:diagnostic imaging*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism*; D005260:Female; D020233:Gait Disorders, Neurologic / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000000981:diagnostic imaging*; D010300:Parkinson Disease / Q000000981:diagnostic imaging*; D065842:Pars Compacta / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography / Q000379:methods*; D013494:Supranuclear Palsy, Progressive / Q000000981:diagnostic imaging*; D013577:Syndrome; D014326:Tropanes
chemical_list: D050483:Dopamine Plasma Membrane Transport Proteins; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane