Arrhythmia insensitive rapid cardiac T₁ mapping pulse sequence

Abstract

Purpose To develop an arrhythmia‐insensitive rapid (AIR) cardiac T1 mapping pulse sequence for quantification of diffuse fibrosis. Methods An arrhythmia‐insensitive cardiac T1 mapping pulse sequence was developed based on saturation recovery T1 weighting, which is inherently insensitive to heart rate and rhythm, and two single‐shot balanced steady‐state free precession image acquisitions with centric k‐space ordering, where T1 calculation is inherently insensitive to T2 effects. Its performance against conventional cardiac T1 mapping based on inversion recovery (i.e., MOLLI) is compared. Phantom experiments (T1 ranging from 535 to 2123 ms) were performed with heart rate and rhythm simulated at 60 and 120 beats per minute (bpm) and arrhythmia using an external triggering device. Ten human subjects and 17 large animals were scanned precontrast and 5, 10, and 15 min after contrast agent administration. Results Compared with the reference T1 mapping, AIR yielded lower normalized root‐mean‐square error than MOLLI (8% vs. 3%, respectively, at 60 bpm, 28% vs. 3%, respectively, at 120 bpm, and 22% vs. 3%, respectively, at arrhythmia). In vivo studies showed that T1 measurements made by MOLLI and AIR were strongly correlated (r = 0.99) but in poor agreement (mean difference = 161.8 ms, upper and lower 95% limits of agreements = 347.5 ms and −24.0 ms). Conclusion Our AIR pulse sequence may be clinically useful for assessment of diffuse myocardial fibrosis in patients. Magn Reson Med 70:1274–1282, 2013. © 2012 Wiley Periodicals, Inc.

Clinical recommendations for cardiovascular magnetic resonance mapping of T1, T2, T2* and extracellular volume: A consensus statement by the Society for Cardiovascular Magnetic Resonance (SCMR) endorsed by the European Association for Cardiovascular Imaging (EACVI)

“…The majority of sequences utilize multiple single-shot bSSFP acquisitions, using inversion preparation (MOLLI [3–5], ShMOLLI [6], ANGIE [7], STONE [8]), saturation preparation (AIR [9], SASHA [10], SAP-T1 [11]) or a combination of the two (SAPPHIRE [12]).…”

Gadolinium free cardiovascular magnetic resonance with 2-point Cine balanced steady state free precession

“…Thus, our results likely reflect the influence of both motion correction artifacts on T1-estimation and regional T1 heterogeneity of healthy tissue that were not included in prior studies. Additionally, our scanner was equipped only with a MOLLI acquisition scheme that has demonstrated sensitivity to MT-effects [ 13 ], and thus the sensitivity of native T1-mapping may have improved with other mapping methods now available [ 15 ], including recently developed arrhythmia insensitive T1 mapping protocols [ 17 ].…”

“…Recent studies using native T1-mapping to identify fibrosis are highly promising [ 12 – 14 ]. However, measured myocardial T1-relaxation times vary between T1-mapping pulse sequences [ 15 ] and myocardial regions [ 16 ], require special sequence modifications to reduce arrhythmia sensitivity [ 17 ], and reconstruction of T1-maps requires motion correction [ 18 ] that has limited some prior measurements to the septum [ 9 , 11 , 19 , 20 ]. In contrast, cine balanced steady state free precession (bSSFP) is ubiquitously used to image ventricular structure and function.…”

How Accurate Is MOLLI T1 Mapping In Vivo? Validation by Spin Echo Methods

“…Other potential factors limiting MOLLI accuracy in vivo, but not studied here, were reviewed in [13] and may include, but are not limited to deviation from the nominal flip angle profile [24], [26], heart rate variability [18], [27], [28], magnetization transfer (MT) effect [26], [29]–[31], motion [19], and B 0 inhomogeneity [13], [32]. Recent works have proposed acquiring MT sensitive data (e.g., by varying RF pulse length) and including MT effect in the signal model [26], [29], [30] for accurate T 1 fitting; however, the utility of this approach for cardiac T 1 mapping using MOLLI remains to be investigated.…”