Cardiac functional magnetic resonance imaging at 7T: Image quality optimization and ultra-high field capabilities

Figure 8 The effect of changing location of the dielectric pad on B1 field homogeneity in volunteers with small body habitus. The place of the pad is indicated by the orange arrow with respect to an axial cross-section of the subject’s chest region (white circle, where subject was scanned in the supine position; A: Anterior, P: Posterior, L: Left, R: Right). Results from an underweight volunteer [body mass index = 19 kg/m², chest expansions = 20 cm (AP) and 30 cm (LR)], as shown on long-axis (A) and short-axis (B) slices. Placing the pad at the anterior left position of the chest (image with red frame) resulted in improved B1 uniformity compared to other anterior and posterior positions, which showed regions of signal nulling (white arrows). This behavior was consistent in all scanned subjects with small body habitus.