Effects of acute dehydration on brain morphology in healthy humans.
Dehydration can affect brain structure which has important implications for human health. In this study, we measured regional changes in brain structure following acute dehydration. Healthy volunteers received a structural MRI scan before and after an intensive 90-min thermal-exercise dehydration protocol. We used two techniques to determine changes in brain structure: a manual point counting technique using MEASURE, and a fully automated voxelwise analysis using SIENA. After the exercise regime, participants lost (2.2% +/- 0.5%) of their body mass. Using SIENA, we detected expansion of the ventricular system with the largest change occurring in the left lateral ventricle (P = 0.001 corrected for multiple comparisons) but no change in total brain volume (P = 0.13). Using manual point counting, we could not detect any change in ventricular or brain volume, but there was a significant correlation between loss in body mass and third ventricular volume increase (r = 0.79, P = 0.03). These results show ventricular expansion occurs following acute dehydration, and suggest that automated longitudinal voxelwise analysis methods such as SIENA are more sensitive to regional changes in brain volume over time compared with a manual point counting technique.
Centre for Neuroimaging Sciences, Institute of Psychiatry, King's College London, London, United Kingdom. matthew.kempton@iop.kcl.ac.uk
Matthew J
MJ
Kempton
Ulrich
U
Ettinger
Anne
A
Schmechtig
Edward M
EM
Winter
Luke
L
Smith
Terry
T
McMorris
Iain D
ID
Wilkinson
Steven C R
SC
Williams
Marcus S
MS
Smith
D000208:Acute Disease; D000328:Adult; D001835:Body Weight / Q000502:physiology; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D001928:Brain Diseases, Metabolic / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D048429:Cell Size; D002552:Cerebral Ventricles / Q000473:pathology / Q000503:physiopathology*; D003681:Dehydration / Q000150:complications / Q000503:physiopathology*; D015444:Exercise / Q000502:physiology; D005081:Exercise Therapy / Q000009:adverse effects; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology; D011237:Predictive Value of Tests; D020542:Third Ventricle / Q000473:pathology / Q000503:physiopathology; D014882:Water-Electrolyte Balance / Q000502:physiology; D055815:Young Adult