How Accurate Is Brain Volumetry? A Methodological Evaluation.

We evaluate the accuracy and precision of different techniques for measuring brain volumes based on MRI. We compare two established software packages that offer an automated image analysis, EMS and SIENAX, and a third method, which we present. The latter is based on the Interactive Watershed Trans- form and a model based histogram analysis. All methods are evaluated with respect to noise, image inhomogeneity, and resolution as well as inter-examination and inter-scanner characteristics on 66 phantom and volunteer images. Furthermore, we evaluate the N3 nonuniformity correction for improving robustness and re- producibility. Despite the conceptual similarity of SIENAX and EMS, important differences are revealed. Finally, the volumetric accuracy of the methods is inves- tigated using the ground truth of the BrainWeb phantom.