Blood T1* correction increases accuracy of extracellular volume measurements using 3T cardiovascular magnetic resonance: Comparison of T1 and T1* maps

Yongning Shang,Zhengwei Zhou,Andreas Greiser,Xiaochun Zhang,Debiao Li,Jian Wang,Xiaoyue Zhou

doi:10.1038/s41598-018-21696-0

Abstract

The goals were to compare the differences between ECVL (extracellular volume derived from myocardial T1 and blood T1), ECVc (combination of myocardial T1 and blood T1*), and ECVnL (derived from myocardium T1* and blood T1*), and to explore the diagnostic accuracy of these factors for discriminating between controls and patients. The Modified Look-Locker Inversion Recovery sequence was performed in 42 subjects to generate both T1 and T1* maps. Native and post-contrast T1 values for myocardium and blood pool were obtained, and ECVL, ECVc, and ECVnL were then calculated. The global ECVc values were smaller than the ECVL values (0.006, 2.11%, p < 0.001) and larger than the ECVnL values (0.06, 21.6%, p < 0.001) in all participants. The ECVc led to a 4–6% increase in the AUC value and a 24–32% reduction in the sample size to differentiate between the controls and other patients when compared with the ECVL. Blood T1* correction can improve the precision of blood T1 values and can consequently increase the accuracy of the extracellular volume fraction measurement. The ECVc can be used to improve diagnostic accuracy and reduce the sample size required for a clinical study.

Highlights

The global ECVc values were smaller than the ECVL values (0.006, 2.11%, p < 0.001) and larger than the ECVnL values (0.06, 21.6%, p < 0.001) in all participants
The effects of T2 sensitivity, magnetization transfer, and inversion efficiency lead to an underestimation of myocardial T1 values[11], the higher signal-to-noise ratio (SNR), which is due to IR preparation and a large number of images, permits MOLLI to more precisely measure T1 values than SASHA
We found that the blood T1* values were higher compared to the blood T1 values for the native T1 acquisitions and were mirrored by inverse effects in post-contrast acquisition in all the participants

Summary

Introduction

The global ECVc values were smaller than the ECVL values (0.006, 2.11%, p < 0.001) and larger than the ECVnL values (0.06, 21.6%, p < 0.001) in all participants. Blood T1* correction can improve the precision of blood T1 values and can increase the accuracy of the extracellular volume fraction measurement. The extracellular volume fraction (ECV), derived from native and post-contrast T1 mapping, reflects the size of the extracellular space in the myocardium and can be used as an important diagnostic biomarker of disease[2], as well as for observation of disease progression[3] and prognosis[4,5]. Modifications of MOLLI sampling schemes (such as 5(3)[3] and 4(1)3(1)[2] for native and post-contrast T1 mapping14) have been proposed to reduce breath-hold duration and reduce heart rate sensitivity, which incrementally increase the precision of T1 measurements. Parameters Age, years Gender, male/female Height, m Weight, kg Body mass index, kg/m2 Body surface area, m2 Systolic blood pressure, mmHg Diastolic blood pressure, mmHg Heart rate, bpm Ejection fraction, % End-diastolic volume index, ml/m2 End-systolic volume index, ml/m2 Stroke volume index, ml/m2 Cardiac index, l/min/m2 Myocardial mass index, g/m2 Hematocrit, % Late gadolinium enhancement positive, n (%)

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Results

Conclusion