Aim:Hypothermia is often induced to reduce brain injury in newborns, following perinatal hypoxic–ischaemic events, and in adults following traumatic brain injury, stroke or cardiac arrest. We aimed to devise a method, based on diffusion-weighted MRI, to measure non-invasively the temperature of the cerebrospinal fluid in the lateral ventricles.Methods:The well-known temperature dependence of the water diffusion constant was used for the estimation of temperature. We carried out diffusion MRI measurements on a 3T Philips Achieva Scanner involving phantoms (filled with water or artificial cerebrospinal fluid while slowly cooling from 41 to 32°C) and healthy adult volunteers.Results:The estimated temperature of water phantoms followed that measured using a mercury thermometer, but the estimates for artificial cerebrospinal fluid were 1.04°C lower. After correcting for this systematic difference, the estimated temperature within the lateral ventricles of volunteers was 39.9°C. Using diffusion directions less sensitive to cerebrospinal fluid flow, it was 37.7°C, which was in agreement with the literature.Conclusion:Although further improvements are needed, measuring the temperature within the lateral ventricles using diffusion MRI is a viable method that may be useful for clinical applications. We introduced the method, identified sources of error and offered remedies for each.

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Purpose: Our goal was to assess the utility of functional magnetic resonance imaging (fMRI) in simultaneous mapping of perceptual and neural visual field deficits, and in the assessment of neural plasticity processes underlying spontaneous and medication‐induced visual field recovery. Methods: Neural function of two patients with predominantly unilateral visual field deficits and three volunteers with simulated scotomas was assessed using fMRI retinotopic mapping procedures. In the patients behavioral testing has also been done by asking for reports in a forced choice manner on the color of a 1.66° diameter circle patch pseudo‐randomly overlaid on the standard fMRI retinopic mapping stimuli. Results: Retinotopic mapping provided a reliable voxel‐based quantification of the extent of both real and simulated visual field deficits. The pattern of BOLD responses in retinotopic visual cortical areas – in particular in the primary visual cortex – showed close correlation with the performance in the perimetry tests, and the behavioral responses obtained during scanning. Moreover, we found a marked difference between true and simulated visual field deficits. Conclusions: The presented fMRI retinotopic mapping techniques are suitable for the simultaneous assessment of the functional and behavioral aspects of visual field loss, thus providing an opportunity to investigate neural plasticity in affected patient populations.