Table 1.

The logarithmic ratio of the peak off-resonant signal to the mean background signal was measured on the positive-contrast images acquired with bSSFP and PARTS: water-suppressed (ws) and combined (comb). The first half of the measurements were performed on the water bottle and the agarose gel phantom data. For both cases, PARTS yields improved suppression compared with bSSFP. For the agarose gel phantom, the increasing background signal at α = 15° reduces the peak contrast for bSSFP as expected. Contrarily, PARTS maintains near-complete background suppression at both tip angles, and the noise level is comparable to the background signal at α = 5°. Therefore, the smaller peak contrast at α = 5° might be attributed to the inadvertent increase in the measured background signal due to noise. The peak contrast was also measured on in vivo mouse images. Similar to the phantom results, PARTS_ws achieves superior background suppression compared with bSSFP. PARTS_comb further improves the peak contrast by simultaneously suppressing the water and fat signals.

Method	bSSFP	PARTSws	PARTScomb
Phantom (water bottle)	7.46	20.04	24.96
Phantom (agarose, α = 5°)	9.51	17.00	–
Phantom (agarose, α = 15°)	7.27	23.45	–
Mouse (axial)	10.34	19.18	28.50
Mouse (coronal)	6.38	17.83	23.77