Introduction
Essential physics and evolution of T1 mapping sequences
Sequence | Building plan: 3 integral parts | Strength | Limitation | Reference | ||
---|---|---|---|---|---|---|
T1 preparation | Imaging readout | Respiratory motion compensation | ||||
Original MOLLI | IR pulse over multiple heartbeats | Single-shot end-diastolic bSSFP | Single breath-hold | – High-quality T1 maps – Good precision (noise resilience) – Widely available – High inter-center reproducibility | – T1 time dependence on T2, MT, and sequence parameters – HR dependence | [6] |
Fixed-recovery MOLLI | IR pulse over multiple heartbeats | Single-shot end-diastolic bSSFP | Single 11-s breath-hold | – Little HR variability – Separate optimization allows precision for both native and post-GBCA regimes | – Requires different protocols for native and post-GBCA scans | [7] |
ShMOLLI | IR pulse over multiple heartbeats | Single-shot end-diastolic bSSFP | Single short 9-s breath-hold | – Short breath-holds via short rest periods of 1 heartbeat – Incomplete magnetization recovery compensated for by conditional data fit – Unified sequence for pre-/post-GBCA scanning – Little HR variability | – Low number of fit images available for use especially in native mapping – Vulnerable to mistriggering as sampling sparse | [8] |
FLASH-MOLLI | IR pulse over multiple heartbeats | Single-shot end-diastolic FLASH | Single 11-s breath-hold | – Avoids off-resonance artifacts (good for high-field strengths) – No T2 dependence – Tailored fitting compensates for disruption of relaxation by FLASH pulses improving accuracy compared to original MOLLI | – Decreased SNR compared to SSFP schemes – Elaborate post-processing limits availability | [9] |
TRASSI | IR pulse over multiple heartbeats | Radial golden-angle FLASH | Single short 5-s breath-hold | – Inherent properties of the radial acquisition, short breath-hold, and HR-adaptable acquisition window provide high resilience to motion artifacts – Tailored fit improves accuracy | – Potential blurring due to view-sharing across heartbeats – Little baseline data – Elaborate post-processing limits availability | [10] |
SASHA | SR preparation over multiple heartbeats | Single-shot bSSFP | Single 10-s breath-hold | – Excellent accuracy as invariant to T2, MT, and inversion efficiency – Alternative reconstruction scheme has been proposed to trade off accuracy against precision – High-contrast imaging scheme available for free-breathing applications | – Still low precision compared to MOLLI – Low SNR baseline images more prone to artifacts – Low blood-myocardial imaging contrast makes post-processing with image registration challenging | [11] |
SMART1 MAP | A series of single-point SR experiments | Single-shot bSSFP | Single breath-hold (13 heartbeats) | – Intra-scan heart rate insensitivity by adapting recovery time to changing heart rates by measuring heartbeats in real time – Good accuracy compared to MOLLI | – Limited data on in vivo clinical applicability; has yet to be validated at scale and on other vendor platforms | |
SAPPHIRE | Hybrid SR/IR over multiple heartbeats | Single-shot bSSFP | Single 10-s breath-hold | – Good accuracy compared to MOLLI – Improved precision compared to SASHA | – Lower precision compared to MOLLI – Low SNR images are prone to artifacts | [14] |
STONE | IR pulse over multiple heartbeats | Single-shot bSSFP | Interleaved multi (5)-slice 55 s free-breathing + registration + real-time slice tracking | – No rest periods between breath-holds as free-breathing improves patient comfort – Improved accuracy due to slice-interleaved scanning | – Potential for slice-tracking failure in heavy breathing patients – Perturbation of blood T1 times due to crosstalk between slices | [15] |
ANGIE | IR pulse over multiple heartbeats | Segmented bSSFP | 41 s free-breathing + diaphragmatic navigator gating | – No rest periods between breath-holds as free-breathing improves patient comfort – Enables high-resolution scans – Motion compensation robust to heavy breathing | – Accuracy comparable to MOLLI (not superior) – Elaborate compressed sensing reconstruction needed before the fit which limits availability | [16] |
Biological basis of ECV
Condition | Native T1
a
[T; sequence; n] |
Z valueb
| Reference |
---|---|---|---|
Aortic stenosis | 1191 ± 34 [3 T; MOLLI; 20] | +0.4 | Chin et al. 2014 [28] |
Essential hypertension | 955 ± 30 [1.5 T; ShMOLLI; 40] | –0.3 | Treibel et al. 2015 [29] |
Hypertrophic cardiomyopathy | 1026 ± 64 [1.5 T; ShMOLLI; 46] | +1.7 | Fontana et al. 2014 [30] |
Dilated cardiomyopathy | 1056 ± 62 [1.5 T; MOLLI; 29] | +0.9 | aus dem Siepen et al. 2015 [31] |
Acute myocardial infarction | 1245 ± 75 [1.5 T; MOLLI; 40] | +9.8 ♦ | Bulluck et al. 2016 [32] |
Fabry disease | 853 ± 50 [1.5 T; ShMOLLI; 38] | –3.6 ♦ | Pica et al. 2014 [33] |
Iron overload | 863 ± 138 [1.5 T; ShMOLLI; 53] | –4.1 ♦ | Sado et al. 2015 [34] |
Light chain amyloidosis | 1130 ± 68 [1.5 T; ShMOLLI; 79] | +4.8 ♦ | Fontana et al. 2014 [30] |
Transthyretin amyloidosis | 1097 ± 43 [1.5 T; ShMOLLI; 85] | +3.8 ♦ | Fontana et al. 2014 [30] |
Acute myocarditis | 1064 ± 37 [1.5 T; MOLLI, 61] | +6.2 ♦ | Hinojar et al. 2015 [35] |
Convalescent myocarditis | 995 ± 19 [1.5 T; MOLLI; 67] | +2.8 ♦ | Hinojar et al. 2015 [35] |
Condition | ECVa (%) [T; n] | Reference |
---|---|---|
Acute myocardial infarction | ⇑ 56 ± 1.4 [1.5 T; 39] | Kidambi et al. 2016 [36] |
Aortic stenosis||
| ↔ 24.3 ± 1.9 [3 T; 50] ⇑ 28.3 ± 1.7 [3 T; 20] | Singh et al. 2015 [37] |
Chin et al. 2014 [28] | ||
Hypertrophic cardiomyopathy | ⇑ 37.1 ± 10.1 [3 T; 50] | Swoboda et al. 2017 [38] |
Dilated cardiomyopathy | ⇑ 27 ± 4 [1.5 T; 29] | aus dem Siepen et al. 2015 [31] |
Systolic heart failure | ⇑ 31.2, 29.0–34.1~
[3 T; 40] | Su et al. 2014 [39] |
Heart failure preserved ejection fraction | ⇑ 28.9, 27.8–31.3~
[3 T; 62] | Su et al. 2014 [39] |
Athletic adaptation | ↓ 22.5 ± 2.6 [1.5 T; 30] | McDiarmid et al. 2016 [40] |
Fabry disease | ↔ 21.7 ± 2.4 [1.5 T; 31] | Thompson et al. 2013 [41] |
Iron overload | ⇑ 31.3 ± 2.8 [1.5 T; 19] | Hanneman et al. 2016 [42] |
Light chain amyloidosis | ⇑ 54 ± 7 [1.5 T; 92] | Fontana et al. 2015 [43] |
Transthyretin amyloidosis | ⇑ 60 ± 7 [1.5 T; 44] | Fontana et al. 2015 [44] |
Acute myocarditis | ⇑ 30, 27–32§
[1.5 T; 48] | Bohnen et al. 2017 [45] |