Table 1.

LIC calibration formulas at 1.5 T and R2* thresholds from literature

Study/method	Sequence; TR; TE; delta-TE; echoes; fit; fs	Calibration formulas to convert R2*[s−1] into LIC in mg/g and in μmol/g	Threshold for LIC > 2 mg/g or 36 μmol/g
Wood [12]	Single-echo gradient-echo; 25 ms; 0.8 ms; 0.25 ms; 16; variable offset; no fs	Fe [mg/g] = 0.0254 × R2* + 0.202 Fe [μmol/g] = R2* / 2.18 + 3.6	71 s−1
Garbowski [27]	Multi-echo gradient-echo; 200 ms 0.93 ms; 0.8 ms; 20; truncation; fs	Fe [mg/g] = 0.032 × R2* − 0.14 Fe [μmol/g] = R2* / 1.74–2.5	67 s−1
Henninger [16]	Multi-echo gradient-echo; 200 ms; 0.99 ms; 1.41 ms; 12; truncation; fs	Fe [mg/g] = 0.024 × R2* + 0.277 Fe [μmol/g] = R2* / 2.31 + 4.8	70 s−1
Hankins [46]	Multi-echo gradient-echo; not mentioned; 1.1 ms; 0.81 ms; 20; truncation; no fs	Fe [mg/g] = 0.028 × R2* × 0.454 Fe [μmol/g] = R2* / 1.98–8.1	88 s−1

TR repetition time, TE echo time, fs fat saturation, LIC liver iron concentration, delta-TE time between two echoes