An optimized method for estimating intracranial volume from magnetic resonance images

The accuracy and efficiency of protocols to measure intracranial volume (IC V) from volumetric magnetic resonance imaging (MRI) studies has not been fo rmally analyzed. The ICV of 30 control participants was obtained by tracing every slice of a MRI dataset on which the cranial cavity appeared, and com pared with estimated ICVs calculated by progressively selecting one of ever y x slices (i.e., "1-in-x") as a sampling strategy. The reliability and pre cision of each sampling strategy was then determined. There was virtually n o reduction in reliability at the 1-in-10 sampling strategy, with a reliabi lity exceeding 0.999. ICV can be confidently traced using a 1-in-10 samplin g strategy, which should result in significant time savings. (C) 2000 Wiley -Liss, Inc.