Fig 2. Measurement of the AC and SI thicknesses. Coronal T2-weighted fast spin-echo (TR/TE, 3000/125.4 ms; section thickness, 2 mm) MR images show the AC thickness (bidirectional arrow) in a control subject (A; AC thickness, 4.30 mm), a patient with AD (B; AC thickness, 3.01 mm), and a patient with FTLD (C; AC thickness, 2.15 mm). The arrows indicate the measured part of the thickness of the SI. Thinning of the SI is noted in the patient with AD and to a lesser degree in the patient with FTLD.