Figure 4
Nomogram plotting the coefficient of signal variation (C v ) across the region of interest for all body types. An average decrease of 42 ± 13% is seen (P < 0.000001; paired Student t test), corresponding to a more uniform B1 field in case of subject-specific radiofrequency (RF) shimming. Changes in Cv with body mass index (BMI) (A), body surface area (BSA) (B), and anterior-posterior/right-left ratio (AP/LR) (C) are shown. As with the mean flip angle, a reduction in Cv is not dependent on body type. The number of subjects with 1a) BMI < 25 kg/m2:14; 1b) BMI = 25.1–30 kg/m2:9; 1c) BMI =30.1–35 kg/m2: 7; 1d) BMI > 35 kg/m2:7; 2a) BSA < 1.9 m2: 11; 2b) BSA = 1.9–2.1 m2: 11; 2c) BSA> 2.1 m2: 15; 3a) AP/RL < 0.6:8; 3b) AP/RL = 0.6–0.7:22 ; 3c) AP/RL >0.7: 7. W/o, without.