The olfactory bulb volume in patients with idiopathic Parkinson's disease.
OBJECTIVE
This study addresses the question of whether the neuropathological findings on the olfactory bulb (OB) in idiopathic Parkinson's disease (IPD) correspond to a detectable change in volume of the OB. Additionally, the relationship between OB volume and residual olfactory function, clinical disease characteristics and age are investigated.


METHODS
Fifty-two IPD patients were investigated and compared to 31 healthy age-matched controls. All participants were scanned using a 3 T magnetic resonance imaging MRI scanner including a T2 DRIVE sequence in coronal slices through the OB. The OB volumes were measured via manual segmentation of the OB. Olfactory testing was carried out using the Sniffin' Sticks test battery.


RESULTS
The OB volume in the IPD group was 42.1 mm³ (SD ± 11.6) for the right and 41.5 mm³ (SD ± 11.7) for the left OB and showed no difference from the controls. Additionally, there were no significant correlations between OB volume and disease characteristics such as disease duration or Unified Parkinson's Disease Rating Scale motor score. Likewise, patients' residual smell function did not correlate with their OB volume. In contrast, controls indicated a correlation between smell function and OB volume.


CONCLUSIONS
The study shows that high resolution MRI does not show a detectable volume loss of the OB in PD patients. It is concluded that OB measurement using in vivo high resolution MRI at 3 T is not helpful to identify IPD.
Department of Neurology, University Hospital Schleswig-Holstein, Kiel Campus, Christian-Albrechts-University Kiel, Kiel, Germany.
L
L
Paschen
Department of Neurology, University Hospital Schleswig-Holstein, Kiel Campus, Christian-Albrechts-University Kiel, Kiel, Germany.
N
N
Schmidt
Department of Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Kiel Campus, Christian-Albrechts-University Kiel, Kiel, Germany.
S
S
Wolff
Department of Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Kiel Campus, Christian-Albrechts-University Kiel, Kiel, Germany.
C
C
Cnyrim
Department of Neurology, University Hospital Schleswig-Holstein, Kiel Campus, Christian-Albrechts-University Kiel, Kiel, Germany.
T
T
van Eimeren
Department of Neurology, University Hospital Schleswig-Holstein, Kiel Campus, Christian-Albrechts-University Kiel, Kiel, Germany.
K E
KE
Zeuner
Department of Neurology, University Hospital Schleswig-Holstein, Kiel Campus, Christian-Albrechts-University Kiel, Kiel, Germany.
G
G
Deuschl
Department of Neurology, University Hospital Schleswig-Holstein, Kiel Campus, Christian-Albrechts-University Kiel, Kiel, Germany.
K
K
Witt
D000368:Aged; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009830:Olfactory Bulb / Q000473:pathology* / Q000503:physiopathology; D010300:Parkinson Disease / Q000473:pathology* / Q000503:physiopathology; D012903:Smell / Q000502:physiology*
Lewy body pathology; MR volumetry; idiopathic Parkinson's disease; non-motor symptoms; olfaction; olfactory bulb volume; olfactory dysfunction; smell function