Images of several samples with and without EuDOTA-from observation pulses. (gly)4. Right column irradiated at agent resonance frequency, which is 3.3 kHz greater than water. Left column is the control experiment irradiated 3.3 kHz below water resonance. The center column is the difference between images, which shows only samples containing Eu (III)–1,4,7,10-tetrazacyclododecane–1,4,7,10-tetrakis (acetamidoacetic acid).