Table 1.

Comparison of Shimming Approaches

	No Blocks	With Blocks	RF Shimming	P 1	P 2
Transmit efficiency ( $\mu \mathrm{T}/\sqrt{\mathrm{W}}$)	0.09 ± 0.01	0.12 ± 0.02	0.11 ± 0.01	<10−4	0.0009
Receive sensitivity (A.U.)	983 ± 120	967 ± 88	1017 ± 88	0.6773	0.1492
T1 image quality	3.76 ± 0.39	4.23 ± 0.63	4.53 ± 0.29	0.0025	0.1188
T2 image quality	3.89 ± 0.39	4.25 ± 0.53	4.63 ± 0.21	0.0053	0.0258
Average power (W)	252 ± 53.9	201 ± 27.4	344 ± 46.3	0.0124	<10−4

Mean values ± standard deviations of the transmit efficiency and receive sensitivity averaged in the region of interest, of the average powers used, and of the scorings on image quality according to the 1 (very bad) to 5 (excellent) grading system. P ₁ values denote the likeliness of the hypothesis $H_0: {\mu }_{\text{no} \text{blocks}}={\mu }_{\text{with} \text{blocks}}$ and P ₂ values denote the likeliness of $H_0: {\mu }_{\text{with} \text{blocks}}={\mu }_{\text{RF} \text{shimming}}$, with values below 0.05 indicating statistically significant changes.

A.U., arbitrary units.