Fig. 14.

Comparison between ¹H and ²³Na cardiac images at 1.5 T of healthy volunteers. Registered axial ¹H MRI FSE images (A and C), cardiac-gated at 60–70 bpm, echo train length = 8, effective TE = 17 ms. Coil sensitivity adjusted axial slices from three-dimensional ²³Na TPI data sets of the heart (B and D) with TR/ TE = 100/0.17 ms, and adiabatic half passage (AHP) excitation from healthy human volunteers. The ²³Na image intensity was adjusted for the coil receiving sensitivity using a computer-generated B₁ field estimate of the coil. The ¹H image data were interpolated in three dimensions so that images (A and C) match the spatial positions of the images (B and D). The resulting in-plane resolution was 128 × 128, at the same slice spacing as the ²³Na data. The three-dimensional ²³Na image data were interpolated to 128 × 128 pixels in-plane to facilitate copying of contours and ROI. Yellow contours are drawn in the ¹H images (A and C) and copied to the ²³Na images (B and D) (shown as gray lines) to guide placement of the ROIs (black lines in the ²³Na images). ROIs were placed in the lateral LV wall, anterior LV wall, and septum (ROI numbers 1–3 or 1–4 in all images). Additional ROIs were placed in the left ventricle for LV blood (ROI number 5) and in the right ventricle for RV blood (ROI number 6). Reproduced with permission from Ref. [174].