Brain Water Measured by Magnetic Resonance Imaging

In vivo estimation of water content in cerebral white matter of brain tumour patients and normal individuals: Towards a quantitative brain oedema definition

“…The calculated water content in WM is in agreement with the known tissue water content in normal human WM obtained by invasive measurements [8,17,20,23]. Secondly, the water Mean T1 and one SD in contralateral WM of the brain tumour patients.…”

“…As invasive measurements of brain water content in normal human brain are impossible for obvious reasons, we employed MR RT imaging, because firstly, the "pure" RT's are closely correlated with in vivo tissue water content [8,12,17,20], and secondly, the high spatial resolution of the MR scanner could be utilized in order to compare different areas of the human brain, and thirdly, in order to obtain a comparable quantity, RT's were used, as they are constant for a given biological system in a given environment [9]. Conventional diagnostic imaging modalities, such as T1-or T2-weighted spin echo images, are inappropriate when quantitative measurements are required, as these types of images only yield arbitrary signal intensities consisting of both T1, T2 and the proton density and have a multiparametric dependence on machine constants and instrumental settings, such as the pulse sequence and the repetition time.…”

“…The magnetic resonance relaxation time (RT) imaging provides a solution to these requirements: it can be done in vivo, it is non-invasive and has a good spatial resolution in order to take normal regional variations of cerebral water content into account. Furthermore, the "building stones" of the RT image, namely the nuclear magnetic RT's of tissue protons, has been shown to correlate well with tissue water content; in fact, in vivo tissue water content can be estimated with an accuracy error within _+ 2% [8,12,17,22], provided careful optimisation of the imaging technique is achieved.…”

Recommendations for the Management of Intracranial Haemorrhage – Part I: Spontaneous Intracerebral Haemorrhage

“…Measuring the osmolar gap correlates better with mannitol serum concentrations than osmolality. A normal osmolar gap concentration was shown to indicate sufficient clearance for repeating mannitol [102,103,104]. …”

Management of Patients with Renal Failure Complicated by Cerebral Oedema

“…The fits recurred despite dexamethasone ther apy in 2 patients and mannitol in the other. Dexamethasone, although producing clinical improvement in patients with cerebral oe dema due to tumours, has not been shown to be effective in reducing the cerebral oedema by nuclear magnetic resonance imaging [11]. Similarly, mannitol has been shown to have little effect in reducing intracranial pressure when either the intracranial pressure has been elevated above 60 mm Hg or in patients with oliguric renal failure [12].…”