Table 3.
List of all quantitative studies with corresponding correlation parameters.
| References | Iron quantification method/field strength (tesla) |
Resolution (mm) XxYxZa/ acquisition time/ number of echoes |
Fixation period before MRI | Histological or physical technique |
Linear regression arameters r = Pearson coefficient correlation r2 = coefficient of determination |
Linear correlation equation A x [Fe] + B |
|---|---|---|---|---|---|---|
| Chen et al., 1989 | T2 (1.5T) | 5 NA NA |
0 | Iron: AAS | p = 0.1 | No correlation |
| House et al., 2007 | R2 (4.7T) | 0.6 × 0.3 × 4 NA 7 |
0 | Iron: AAS | r = 0.797, p < 0.0001 | A = 0.098 B = 16.2 |
| House et al., 2008 | R1 (1.4T) R2 (1.4T) |
NA NA NA |
0 | Iron: ICP-AES | R1: r = 0.72, p < 0.0001 R2: r = 0.70, p < 0.0001 |
R1: A = 0.0034, B = 0.9 R2: A = 0.031, B = 10.0 |
| Yao et al., 2009b | R2* (1.5,3,7T) | 0.7x0.7x0.7 3h 00 min 00 s 5 |
NA | Iron: ICP-MS | r = 0.93, p < 0.05b | A = 0.0099bB = 1.71 |
| Langkammer et al., 2010 | R2 (3T) R2* (3T) |
1 × 1 × 4 0h 06 min 27 s 32 1 × 1 × 4 0h 07 min 35 s 12 |
0 | Iron: ICP-MS | R2: r = 0.67, p < 0.001 R2*: r = 0.90, p < 0.001 |
R2: A = 0.04, B = 8.5 R2*: A = 0.27, B = 14.3 |
| Hopp et al., 2010 | Phase (1.5T) | 0.5 × 0.5 × 2 NA NA |
NA | Iron: XRF | Phase: r2 = 0.81, p < 0.0001 | Phase: A = 0.0025, B = −0.13 |
| Antharam et al., 2012 | R2 (14.1T) R2* (14.1T) |
0.062 × 0.062 × 0.08 1h 40 min 00 s 15 0.062 × 0.062 × 0.08 1 h 30 min 00 s 18 |
0 | Iron: XRF | R2: r2 = 0.48 R2*: r2 = 0.43 |
NA NA |
| Langkammer, 2012 | QSM (3T) | 0.5 × 0.5 × 2 0 h18 min 00 s NA |
0 | Iron: ICP-MS | r = 0.87, p < 0.001 | A = 0.00097, B = −0.037 |
| Langkammer et al., 2012 | R2* (3T) Phase (3T) |
0.5 × 0.5 × 2 0 h 17 min 27 s 2 |
0 | Iron: ICP-MS | R2*: r = 0.37 p < 0.01 Phase: r = −0.14, p = 0.33 |
R2*: A = 0.12, B = 22.38 Phase: NA |
| Walsh et al., 2013 | T2 (4.7T) R2 (4.7T) R2* (4.7T) Phase (4.7T) |
0.25 × 0.25 × 1–2 0h 06 min 48 s NA 0.8–1 × 1 × 4–5 0 h 15 min 36 s 18–24 0.8–1 × 1 × 2 |
0 | Iron: Perls | T2: r2 = 0.511–0.650 p < 0.001 R2: r2 = 0.489–0.615 p < 0.001 R2*: r2 = 0.628–0.685 p < 0.001 Phase: r2 = 0.441–0.596 p < 0.001 |
NA NA NA NA |
| 0 h 08 min 54 s 10 0.5 × 0.5 × 2 0 h 06 min 36 s NA |
||||||
| Zheng et al., 2013 | QSM (3T) | 0.5 × 0.5 × 0.7 NA 11 |
6 hours | Iron: XRF | r = 0.74-0.87 p = NA | A = 0.79-0.80,B = −3.66-+10.81 |
| Stüber et al., 2014c | R1 (7T) R2* (7T) QSM (7T) |
0.2 × 0.2 × 0.2 NA 2 0.2 × 0.2 × 0.2 NA 8 0.2 × 0.2 × 0.2 NA 8 |
30 days | Iron: PIXE | R1c: r = 0.871 p < 0.001 R2*c: r = 0.933 p < 0.001 QSMc: r = 0.812 p < 0.001 |
A = 0.249d, B = 1.129 A = 0.0526d, B = 45.87 A = 0.000143d, B = −0.0251 |
| Tan et al., 2014 | QSM (3T) | NA × NA × 0.4 0 h 02 min 29 s NA |
NA | Iron: ICP-MS | r = 0.86 p < 0.01 | NA |
| Birkl et al., 2015 | R2' (3T) TcR2' (3T) |
1 × 1 × 2 0 h 20 min 0 s 6 (T2*) |
0 | Iron: ICP-MS | R2': r2 = 0.94 p < 0.001 TcR2': r2 = 0.98 p < 0.001 |
A = 0.11, B = 8.85 A = −0.004, B = 0.03 |
| Sun et al., 2015 | QSM (4.7T) | 0.8–1 × 1 × 2 0 h 08 min 54 s 10 |
0 | Iron: Perls | r2 = 0.62-0.86 p < 0.001 | NA |
| Wisnieff et al., 2015 | R2* (3T) QSM (3T) |
0.7 × 0.7 × 0.7 NA 12 |
NA | Iron: LA-ICP-MS | NA | NA |
| Dusek et al., 2016 | R2* (7T) | 0.5 × 0.5 × 2 0 h 35 min 00 s 8 |
NA | Iron:Turnbull + DAB + ammonium sulfide and AAS | Turnbull: r2 = 0.57-0.64 p = 0.01-0.02 AAS: r2 = 0.70, p < 0.001 | NA |
| Lee et al., 2016 | T2* (7T) | 0.136 × 0.136 × 0.5 0 h 25 min 0 s 10 |
3-5 months | Iron: Perls | r = −0.45 -−0.63 p < 0.001 | A = −8.05-−12.64eB = 10.83-11.95e |
| Wallace et al., 2016 | PSIR | 0.3 × 0.3 × 0.6 6 h 35 min 0 s NA |
Several months | Iron: Perls + DAB and Turnbull + DAB | r = 0.18 p = NA | NA |
| Birkl et al., 2017 | R2* (3T) TcR2* (3T) | 0.5 × 0.5 × 2 0 h 06 min 28 s |
NA | Ferritin: IHC (light chain) | R2*: r = 0.14 p = 0.36 TcR2*: r = −0.66 p < 0.001 |
A = 0.06, B = 37.51 A = −0.0032, B = −0.7756 |
| 6 | ||||||
| Wiggermann et al., 2017 | QSM (3T) | 0.4 × 0.4 × 0.8 0 h 14 min 20 s NA |
NA | Iron: Turnbull + ammonium sulfide + DAB | r2 = 0.02 p = 0.35 | NA |
| Bagnato et al., 2018 | R2* (7T) | 0.7 × 0.7 × 0.7 2 h 16 min 52 s 5 |
Several years | Iron: Turnbull + DAB+ ammonium sulfide | r = 0.42-0.86 p < 0.01 | NA |
| Bulk et al., 2018a | R2* (7T) | × 0.1 × 0.1 3 h 30 min 0 s 4 |
4 weeks – 3 years | Iron: EPR and SQUID | ρ = 0.12f p>0.05 | NA |
| Bulk et al., 2018b | T2* (7T) | / 3 h 30 min 0 s 1 |
NA | Iron: Perls + DAB | r = 0.6 p = NA | NA |
| Lee et al., 2018 | T1map (7T) T2map (7T) T2*map (7T) T2*/T2 (7T) T2*/T22 (7T) SWI (7T) QSM (7T) |
0.136 × 0.136 × 0.5 NA 10–15 |
NA | Iron: Perls | T1map: r = −0.37– −0.11 p < 0.001 T2map: r = −0.61– −0.35 p < 0.001 T2*map: r = −0.65– −0.11 p < 0.001 T2*/T2: r = −0.64– −0.15 p < 0.001 T2*/T22: r = −0.43– −0.26 p < 0.001 SWI: r = −0.65– −0.18 p < 0.005 QSM: r = 0.29–0.44 p < 0.001 |
NA |
| Hametner et al., 2018 | R2* (7T) QSM (7T) |
0.43 × 0.43 × 0.65 0 h 13 min10 s 4 |
0 | Iron: Turnbull + ammonium sulfide + DAB Ferrozine assay |
Turnbull: R2*: r = 0.619 p < 0.0001 Turnbull: QSM: r = 0.445 p < 0.0001 Ferrozine: R2*: r = 0.738 p = NA Ferrozine: QSM: r = 0.755 p = NA |
A = 0.51236, B = 15.2827 A = 0.0006723B = −0.04618 A = 1.10, B = −7.13 A = 0.00196B = −0.10 |
AAS, atomic absorption spectrometry; CAA, cerebral amyloid angiopathy; DAB, diaminobenzidine; EPR, electron paramagnetic resonance; ICP-AES, inductively coupled plasma atomic emission spectrometry; ICP-MS, inductively coupled plasma mass spectrometry; IHC, immunohistochemistry; LA-ICP-MS, laser ablation ICP-MS; MSA, multiple system atrophy; NA, not available; PIXE, particle induced X-ray emission; PSIR, T1 phase sensitive inversion recovery; QSM, quantitative susceptibility mapping; SQUID, superconducting quantum interference device magnetometer; SWI, susceptibility weighted images;TcR2*, temperature coefficient R2*; XRF, X-ray fluorescence.
a
XxY, in-plane resolution; Z, thick section
b
iron correlated with R2*/tesla rather than R2*
c
linear equation parameters determined with myelin inference
d
correlation with iron expressed in kg/mg dry weight determined by PIXE
e
linear equation parameters determined with neuromelanin inference
f
Spearman correlation coefficient.