MR-Intracranial pressure (ICP): a method to measure intracranial elastance and pressure noninvasively by means of MR imaging: baboon and human study.

PURPOSE: To develop a noninvasive method for intracranial elastance and intracranial pressure (ICP) measurement. MATERIALS AND METHODS: Intracranial volume and pressure changes were calculated from magnetic resonance (MR) imaging measurements of cerebrospinal fluid (CSF) and blood flow. The volume change was calculated from the net transcranial CSF and blood volumetric flow rates. The change in pressure was derived from the change in the CSF pressure gradient calculated from CSF velocity. An elastance index was derived from the ratio of pressure to volume change. The reproducibility of the elastance index measurement was established from four to five measurements in five healthy volunteers. The elastance index was measured and compared with invasive ICP measurements in five patients with an intraventricular catheter at MR imaging. False-positive and false-negative rates were established by using 25 measurements in eight healthy volunteers and six in four patients with chronically elevated ICP. RESULTS: Th...