Figure 2.

Reference line and region of interests set for correlation coefficient measurement of the acetone dilution phantoms and of the volunteers. (a) A healthy 35‐yr‐old man. Coronal sections of volunteers, pure water, and diluted acetone were obtained. The coronal section was arranged to cross the anterior commissure ‐ posterior commissure line; (b) the magnetic resonance image (TI 2000 ms) shows a 4.75‐mm diameter region of interest (white open circle) set in the lateral ventricular anterior horn, in pure water, and in acetone (10–100 v/v%).