Magnetic resonance was performed on a 1.5–T MRI unit with a quadrature head coil. T1-weighted sequences were analyzed for this study. From the axial slice of structural neuroimaging (Magnetic Resonance Imaging), the BFI was measured on a plane parallel to the temporal lobe plane at the level of the maximum width between the tips of the frontal horns of the lateral ventricles, and defined as the ratio of this value to the diameter of the inner skull table at the same level. The resulting ratio was then multiplied by 100 and expressed as a percentage (Figure 1).15,16,23,24 A graded caliper with a 0.1 mm scale was used for this linear measurement on film copy.