Table 4.
Comparison of recently reported phantoms for cardiac T1 mapping quality assurance
| Dedicated T1 device | Combined T1/T2 device | |||
|---|---|---|---|---|
| Phantom | HCMR (cardiac specific) | Brompton (cardiac specific) | T1MES (cardiac specific) | ISMRM/NIST system phantom (not cardiac specific) |
| Field strength specificity | ☒ | ☒ | ☑ | ☒ |
| Tube ingredients | NiCl2-doped agar + carrageenan | NiCl2-doped agar | NiCl2-doped agar | NiCl2-doped water, MnCl2-doped agar |
| Structure | 9 T1/T2 tubes in an amber PVC sealed jar that is ~ 25% smaller in total volume compared to T1MES. | Air-filled box containing 4 duplicate T1/T2 glued glass tubes (total 8) requires cylindrical MRI test bottles on either side for B1 field/reference frequency calibration. | 9 plastic T1/T2 tubes in an amber PVC sealed jar with inter-tube gaps packed with a carefully specified agarose/ HDPE plastic macrobead/NiCl2-doped fill that flattened the B1 field and provided sufficient B0 homogeneity to obviate the need for side phantoms. | A layer of 14 T1 spheres and a separate layer of 14 T2 spheres so no unified T1/T2 compartment representing the relaxation parameters of the human heart. |
| Cardiac T1/T2coverage | Health and disease, 9 biologies but limited T2 coverage (57 and 75 ms). | Health only, 4 biologies: (1) native myocardium, (2) native blood, (3) post-GBCA myocardium, and (4) post-GBCA blood. | Health and disease, 9 biologies and broad T2 coverage (1.5 T, 44, 48, 50, 155, 189, and 243 ms). Also see Supplementary Table 3. | Health and disease, but of the 14 T1 spheres (ranging from 21 to 2038 ms), half are not useful to cardiac T1 mapping as T1 times are too short for either native or post-GBCA myocardium/blood. Half the T2 spheres (ranging from 11 to 581 ms) are also anti-physiological for cardiac mapping. Also, the T1/T2 ratio is not representative of cardiac tissue. |
| MT coverage | – | – | – | – |
| Regulatory clearance | – | – | FDA, CE-mark | – |
| Developers | Piechnik et al. | Vassiliou et al. | Captur et al. | NIST/ISMRM |
CE Conformitée-Europeen, FDA Food and Drug Administration, HDPE high-density polyethylene, MT magnetization transfer, PVC poly vinyl chloride