Phantom construction was based on a high-resolution (1mm isotropic voxels) low-noise data set that was created by registering 27 scans (T1-weighted gradient echo acquistions with TR/TE/FA=18ms/10ms/30deg) of the same individual in stereotaxic space where they were subsampled and intensity averaged . The volume contains voxels and covers the brain completely, extending from the top of the scalp to the base of foramen magnum (see Fig. 1). As a direct result of the high signal-to-noise ratio (SNR), this single subject average dataset, dubbed CJH27, exhibits fine anatomical details such as the claustrum, subthalamic nuclei, gray matter bridges between the caudate and putamen, and vessels passing through the lentiform nucleus; details normally obscured by noise in single images. The 3D, high-resolution, anatomically accurate human brain phantom was created by manually correcting an automatically classified and preprocessed version of the MRI volume. The following sections describe the process in more detail.