Total Mapping Toolbox (TOMATO): An open source library for cardiac magnetic resonance parametric mapping

Werys, Konrad; Dragonu, Iulius; Zhang, Qiang; Popescu, Iulia A.; Hann, Evan; Puchta, Henrike; Kubik, Agata; Polat, Dogan; Wu, Cody; Moon, Niall; Barutçu, Ahmet; Ferreira, Vanessa M.

doi:10.1016/j.softx.2019.100369

Cited by 8 publications

(8 citation statements)

References 16 publications

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“…T1-maps were acquired based on the ShMOLLI sequence as previously published 19 , prototype version WIP1048. Quality assessment of ShMOLLI T1-maps using parametric goodness-of-fit (R 2 ) maps were available in-line at time of acquisition 19 , 28 , based on open source reconstruction 29 . MOLLI (MyoMaps, Siemens Healthcare, Erlangen, Germany) T1-maps were acquired from vendor-provided product protocols: “Long T1” MOLLI 5(3)3 was used for rest and stress native T1-mapping and “Short T1” MOLLI 4(1)3(1)2 was used for post-contrast T1-mapping.…”

Section: Methodsmentioning

confidence: 99%

Cardiac stress T1-mapping response and extracellular volume stability of MOLLI-based T1-mapping methods

Burrage

Shanmuganathan

Zhang

et al. 2021

Sci Rep

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Stress and rest T1-mapping may assess for myocardial ischemia and extracellular volume (ECV). However, the stress T1 response is method-dependent, and underestimation may lead to misdiagnosis. Further, ECV quantification may be affected by time, as well as the number and dosage of gadolinium (Gd) contrast administered. We compared two commonly available T1-mapping approaches in their stress T1 response and ECV measurement stability. Healthy subjects (n = 10, 50% female, 35 ± 8 years) underwent regadenoson stress CMR (1.5 T) on two separate days. Prototype ShMOLLI 5(1)1(1)1 sequence was used to acquire consecutive mid-ventricular T1-maps at rest, stress and post-Gd contrast to track the T1 time evolution. For comparison, standard MOLLI sequences were used: MOLLI 5(3)3 Low (256 matrix) & High (192 matrix) Heart Rate (HR) to acquire rest and stress T1-maps, and MOLLI 4(1)3(1)2 Low & High HR for post-contrast T1-maps. Stress and rest myocardial blood flow (MBF) maps were acquired after IV Gd contrast (0.05 mmol/kg each). Stress T1 reactivity (delta T1) was defined as the relative percentage increase in native T1 between rest and stress. Myocardial T1 values for delta T1 (dT1) and ECV were calculated. Residuals from the identified time dependencies were used to assess intra-method variability. ShMOLLI achieved a greater stress T1 response compared to MOLLI Low and High HR (peak dT1 = 6.4 ± 1.7% vs. 4.8 ± 1.3% vs. 3.8 ± 1.0%, respectively; both p < 0.0001). ShMOLLI dT1 correlated strongly with stress MBF (r = 0.77, p < 0.001), compared to MOLLI Low HR (r = 0.65, p < 0.01) and MOLLI High HR (r = 0.43, p = 0.07). ShMOLLI ECV was more stable to gadolinium dose with less time drift (0.006–0.04% per minute) than MOLLI variants. Overall, ShMOLLI demonstrated less intra-individual variability than MOLLI variants for stress T1 and ECV quantification. Power calculations indicate up to a fourfold (stress T1) and 7.5-fold (ECV) advantage in sample-size reduction using ShMOLLI. Our results indicate that ShMOLLI correlates strongly with increased MBF during regadenoson stress and achieves a significantly higher stress T1 response, greater effect size, and greater ECV measurement stability compared with the MOLLI variants tested.

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Section: Methodsmentioning

confidence: 99%

Cardiac stress T1-mapping response and extracellular volume stability of MOLLI-based T1-mapping methods

Burrage

Shanmuganathan

Zhang

et al. 2021

Sci Rep

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“…However, it is important to note that the way of implementation via the Python wrapper facilitated code readability and maintenance. It is noted that a C++ implementation for T1 mapping was recently demonstrated by Werys et al [28], although we did not compare their method with our methods.…”

Section: Discussionmentioning

confidence: 97%

Fast calculation software for modified Look-Locker inversion recovery (MOLLI) T1 mapping

Kim

Lee

et al. 2021

BMC Med Imaging

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Background The purpose of this study was to develop a software tool and evaluate different T1 map calculation methods in terms of computation time in cardiac magnetic resonance imaging. Methods The modified Look-Locker inversion recovery (MOLLI) sequence was used to acquire multiple inversion time (TI) images for pre- and post-contrast T1 mapping. The T1 map calculation involved pixel-wise curve fitting based on the T1 relaxation model. A variety of methods were evaluated using data from 30 subjects for computational efficiency: MRmap, python Levenberg–Marquardt (LM), python reduced-dimension (RD) non-linear least square, C++ single- and multi-core LM, and C++ single- and multi-core RD. Results Median (interquartile range) computation time was 126 s (98–141) for the publicly available software MRmap, 261 s (249–282) for python LM, 77 s (74–80) for python RD, 3.4 s (3.1–3.6) for C++ multi-core LM, and 1.9 s (1.9–2.0) for C++ multi-core RD. The fastest C++ multi-core RD and the publicly available MRmap showed good agreement of myocardial T1 values, resulting in 95% Bland–Altman limits of agreement of (− 0.83 to 0.58 ms) and (− 6.57 to 7.36 ms) with mean differences of − 0.13 ms and 0.39 ms, for the pre- and post-contrast, respectively. Conclusion The C++ multi-core RD was the fastest method on a regular eight-core personal computer for pre- or post-contrast T1 map calculation. The presented software tool (fT1fit) facilitated rapid T1 map and extracellular volume fraction map calculations.

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“…All reference T1 and T2 maps were calculated offline by a C++ library [11]. We analyzed the T1 and T2 using the robust mean values from the circular (15 mm Q. Zhang, K. Werys, I.A.…”

Section: Methodsmentioning

confidence: 99%

Quality assurance of quantitative cardiac T1-mapping in multicenter clinical trials – A T1 phantom program from the hypertrophic cardiomyopathy registry (HCMR) study

Zhang

Werys

Popescu

et al. 2021

International Journal of Cardiology

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Background: Quantitative cardiovascular magnetic resonance T1-mapping is increasingly used for myocardial tissue characterization. However, the lack of standardization limits direct comparability between centers and wider roll-out for clinical use or trials. Purpose: To develop a quality assurance (QA) program assuring standardized T1 measurements for clinical use. Methods: MR phantoms manufactured in 2013 were distributed, including ShMOLLI T1-mapping and reference T1 and T2 protocols. We first studied the T1 and T2 dependency on temperature and phantom aging using phantom datasets from a single site over 4 years. Based on this, we developed a multiparametric QA model, which was then applied to 78 scans from 28 other multi-national sites. Results: T1 temperature sensitivity followed a second-order polynomial to baseline T1 values (R 2 > 0.996). Some phantoms showed aging effects, where T1 drifted up to 49% over 40 months. The correlation model based on reference T1 and T2, developed on 1004 dedicated phantom scans, predicted ShMOLLI-T1 with high consistency (coefficient of variation 1.54%), and was robust to temperature variations and phantom aging. Using the 95% confidence interval of the correlation model residuals as the tolerance range, we analyzed 390 ShMOLLI T1-maps and confirmed accurate sequence deployment in 90%(70/78) of QA scans across 28 multiple centers, and categorized the rest with specific remedial actions. Conclusions: The proposed phantom QA for T1-mapping can assure correct method implementation and protocol adherence, and is robust to temperature variation and phantom aging. This QA program circumvents the need of frequent phantom replacements, and can be readily deployed in multicenter trials.

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Total Mapping Toolbox (TOMATO): An open source library for cardiac magnetic resonance parametric mapping

Cited by 8 publications

References 16 publications

Cardiac stress T1-mapping response and extracellular volume stability of MOLLI-based T1-mapping methods

Cardiac stress T1-mapping response and extracellular volume stability of MOLLI-based T1-mapping methods

Fast calculation software for modified Look-Locker inversion recovery (MOLLI) T1 mapping

Quality assurance of quantitative cardiac T1-mapping in multicenter clinical trials – A T1 phantom program from the hypertrophic cardiomyopathy registry (HCMR) study

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