Examples of three 1H CSI slices from a 3D CSI RESEGAW dataset in rat brain, positioned at +0.7 mm (A), −2.8 mm (B) and −6.2 mm (C) from bregma. The temperature distribution in these three slices was calculated using eq. [1]. The average temperature was 36.4 ± 0.3 °C, 36.5 ± 0.2 °C and 36.3 ± 0.3 °C, respectively. The presence of a temperature gradient of ~0.3°C across cortex was demonstrated by measuring the average temperatures in the upper (UC), middle (MC) and lower (LC) cortical layers, indicated by the three red boxes in (A). Moreover, significantly higher temperatures (>0.5°C compared to cortex) were measured in corpus callosum (CC, red oval in (A)), hippocampus (HC, red oval in (B)) and superior colliculus (SC, red oval in (C)). [R1.6] The location of the surface coil relative to the animal brain is also indicated. [R2.2]