More articles from ADULT BRAIN
- Responses of the Human Brain to Mild Dehydration and Rehydration Explored In Vivo by 1H-MR Imaging and Spectroscopy
Serial T1WI and 1H-MR spectroscopy data were acquired in 15 healthy individuals at normohydration, at 12 hours of dehydration, and during 1 hour of oral rehydration. Osmotic challenges were monitored by serum measures, including osmolality and hematocrit. With dehydration, serum osmolality increased by 0.67% and brain tissue fluid decreased by 1.63%. MR imaging morphometry demonstrated corresponding decreases of cortical thickness and volumes of the whole brain, cortex, white matter, and hypothalamus/thalamus. These changes reversed during rehydration. The authors conclude that it is essential to control for hydration levels in studies on brain morphometry and metabolism in order to avoid confounding the findings.
- Optimal Diagnostic Indices for Idiopathic Normal Pressure Hydrocephalus Based on the 3D Quantitative Volumetric Analysis for the Cerebral Ventricle and Subarachnoid Space
Patients with suspected idiopathic normal pressure hydrocephalus (NPH) on the basis of the ventriculomegaly and a triad of symptoms underwent the CSF tap test. CSF volumes were extracted from a T2-weighted 3D spin-echo SPACE sequence on 3T MR imaging and were quantified semiautomatically. Twenty-four patients with tap-positive idiopathic NPH, 25 patients without response to the tap test, and 23 age-matched controls were included. The CSF volume of the parietal convexity had the highest area under the ROC curve in the discrimination of the tap-test response (0.768), followed by the z-Evans Index (0.758), and the upper-to-lower subarachnoid space ratio index (0.723). CSF volume of the parietal convexity of less than 38 mL, upper-to-lower subarachnoid space ratio of less than 0.33, and a z-Evans Index of greater than 0.42 are the newly proposed useful indices for idiopathic NPH diagnosis.