FF Parametric Maps:

%FF parametric maps were obtained using both LP-1 (Fig.2a) and LP-2 protocols (Fig. 2b). Results on vials 1-12 were in good agreement with the expected values +- 0.62 and 1.82. In vials 13-15 %FF measurements were not reliable, due to their high percentage of fat (>50%). The %FF measurements on each vial are summarized in Table 1 along with their SDs.

Fig 2: Color-coded %FF maps in FF-MRI phantom using (a) LP-1 and (b) LP-2 protocol.

Statistical Analysis: The Bland-Altman analysis showed mean differences of 2.3% and 1.8% for LP-1 and LP-2, respectively. LP-1 comparison (Fig. 3a) showed a mean %FF value difference of +2.3%, with a 95% Confidence Interval (CI) standard deviation (SD) range of -7.1% to 11.7%. The SD span was 18.8% for the %FF range (1–50) %. For LP-2 comparison (Fig. 3b), the mean %FF value difference was +1.8%, with a 95% CI SD range of -13.0% to 16.6%. The SD span was 29.6% for the %FF range (1–50) %. CCC values were greater than 99.0% for both protocols, indicating strong agreement with the reference values.

Fig 3: Different Bland-Altman (BA) plots comparing mean %FF measurements between mean %FF from LP-1 and LP-2 protocols in reference to the FF-MRI phantom values which are used as the gold standard: (a) BA between the LP-1 and the FFMRI phantom, (b) BA between the LP-2 and FF-MRI phantom