Multicenter Test-Retest and Acquisition Protocol Reproducibility of Liver Iron Quantification

Author

Lu Mao

Statistical analysis

A placeholder for description of methods.

Repeatability analysis

The number of pairs for test-retest repeatability analysis by protocol, field strength, and lobe is listed below.

Number of test-retest pairs in analysis
Protocol Field Lobe n
P01 1.5T Left lobe 480
P01 1.5T Right lobe 384
P01 3.0T Left lobe 470
P01 3.0T Right lobe 376
P02 1.5T Left lobe 480
P02 1.5T Right lobe 384
P02 3.0T Left lobe 460
P02 3.0T Right lobe 368
P04 1.5T Left lobe 475
P04 1.5T Right lobe 380
P04 3.0T Left lobe 430
P04 3.0T Right lobe 344
P08 1.5T Left lobe 455
P08 1.5T Right lobe 364
P08 3.0T Left lobe 430
P08 3.0T Right lobe 344

The test-retest bias, coefficient of repeatability (CR), intra-class correlation (ICC) coefficient and 95% confidence interval (CI) are summarized by protocol, field strength, and lobe in Table 1 below.

Table 1: Test-retest repeatability analysis by protocol, field strength, and lobe.
Protocol Field Lobe Bias CR ICC (95% CI) p-value
P01 1.5T Left 2.8 74.4 0.989 (0.986, 0.99) < 0.001
P01 1.5T Right -1.1 52.6 0.995 (0.994, 0.996) < 0.001
P01 3.0T Left -9.4 247.9 0.968 (0.962, 0.974) < 0.001
P01 3.0T Right -5.9 131.2 0.992 (0.99, 0.993) < 0.001
P02 1.5T Left 0.4 108.5 0.97 (0.964, 0.975) < 0.001
P02 1.5T Right 0.1 72.1 0.989 (0.987, 0.991) < 0.001
P02 3.0T Left 1.9 266.9 0.959 (0.951, 0.966) < 0.001
P02 3.0T Right -6.8 119.0 0.992 (0.991, 0.994) < 0.001
P04 1.5T Left -2.4 107.2 0.968 (0.961, 0.973) < 0.001
P04 1.5T Right 0.8 70.3 0.989 (0.987, 0.991) < 0.001
P04 3.0T Left 14.6 281.8 0.887 (0.865, 0.905) < 0.001
P04 3.0T Right 9.3 208.9 0.964 (0.956, 0.971) < 0.001
P08 1.5T Left -1.7 123.5 0.948 (0.938, 0.957) < 0.001
P08 1.5T Right 0.7 98.7 0.974 (0.968, 0.979) < 0.001
P08 3.0T Left 5.0 235.3 0.854 (0.826, 0.878) < 0.001
P08 3.0T Right 10.7 312.2 0.869 (0.84, 0.892) < 0.001

Bland-Altman plots of test-retest repeatability by protocol and lobe for 1.5T and 3.0T are shown in Figure 1 and Figure 2, respectively.

Figure 1: Bland-Altman plot of test-retest repeatability of R2* in 1.5T by protocol and lobe.
Figure 2: Bland-Altman plot of test-retest repeatability of R2* in 3.0T by protocol and lobe.