On the accuracy and precision of cardiac magnetic resonance T<sub>2</sub> mapping: A high‐resolution radial study using adiabatic T<sub>2</sub> preparation at 3 T

Bano, Wajiha; Feliciano, Hélène; Coristine, Andrew J.; Stuber, Matthias; Heeswijk, Ruud B. van

doi:10.1002/mrm.26107

Cited by 17 publications

(22 citation statements)

References 47 publications

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“…Retrospective analysis of the 4 discarded maps showed that the main cause of insufficient image quality was most likely insufficient communication with the performing technologist, because in 3 of the 4 patients, only routine shimming was performed, whereas cardiac shimming is essential for balanced steady-state free precession–based cardiac pulse sequences at 3 T. 14 This resulted in several dark-band artifacts (banded signal voids) through the heart, which in turn caused the self- navigation to perform suboptimally. In addition, in 2 of the 4 patients, the timing was most likely not set to the correct phase of the heart, resulting in too noisy and blurred data.…”

Section: Discussionmentioning

confidence: 99%

Three-Dimensional Self-Navigated T2 Mapping for the Detection of Acute Cellular Rejection After Orthotopic Heart Transplantation

Heeswijk¹,

Piccini²,

Tozzi³

et al. 2017

Transplantation Direct

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BackgroundT2 mapping is a magnetic resonance imaging technique measuring T2 relaxation time, which increases with the myocardial tissue water content. Myocardial edema is a component of acute cellular rejection (ACR) after heart transplantation. This pilot study compares in heart transplantation recipients a novel high resolution 3-dimensional (3D) T2-mapping technique with standard 2-dimensional (2D) T2-mapping for ACR detection.MethodsConsecutive asymptomatic patients (n = 26) underwent both 3D T2 mapping and reference 2D T2 mapping magnetic resonance imaging on the day of endomyocardial biopsy (EMB). 3D T2 maps were obtained at an isotropic spatial resolution of 1.72 mm (voxel volume 5.1 mm3). 2D and 3D maps were matched anatomically, and maximum segmental T2 values were compared blinded to EMB results. In addition, all 3D T2 maps were rendered as 3D images and inspected for foci of T2 elevation.ResultsT2 values of segments from 2D and reformatted 3D T2 maps agreed (p > 0.5). The highest 2D segmental T2 values were 49.9 ± 4.0 ms (no ACR = 0R, n = 18), 48.9 ± 0.8 ms (mild ACR = 1R, n = 3), and 65.0 ms (moderate ACR = 2R). Rendered 3D T2 maps of cases with 1R showed foci with significantly elevated T2 signal (T2 = 58.2 ± 3.6 ms); 5 cases (28%) in the 0R group showed foci with increased T2 values (>2 SD above adjacent tissue) that were not visible on the 2D T2 maps.ConclusionsThis pilot study in a small cohort suggests equivalency of standard segmental analysis between 3D and 2D T2-mapping. 3D T2 mapping provides a spatial resolution that permits detection of foci with elevated T2 in patients with mild ACR.

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Section: Discussionmentioning

confidence: 99%

Three-Dimensional Self-Navigated T2 Mapping for the Detection of Acute Cellular Rejection After Orthotopic Heart Transplantation

Heeswijk¹,

Piccini²,

Tozzi³

et al. 2017

Transplantation Direct

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“…The optimized LIBRE‐Iso3DGRE protocol was then used to acquire the four input images (TE T2prep = 0–23–38–53 msec) that are needed in order to calculate a T 2 map. TE T2prep = 23 msec was the minimum possible duration of the T 2 preparation module, which was incremented in steps of 15 msec to cover the physiological range of cartilage T 2 values and to maximize T 2 fitting precision . The empirical fit offset was chosen to minimize the intercept value in the linear regression between the SE and the LIBRE‐Iso3DGRE T 2 values.…”

Section: Methodsmentioning

confidence: 99%

Simultaneous fat‐free isotropic 3D anatomical imaging and T₂ mapping of knee cartilage with lipid‐insensitive binomial off‐resonant RF excitation (LIBRE) pulses

Colotti

Omoumi

Heeswijk

et al. 2018

Magnetic Resonance Imaging

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Background Improved knee cartilage morphological delineation and T2 mapping precision necessitates isotropic 3D high‐resolution and efficient fat suppression. Purpose To develop and assess an isotropic 3D lipid‐insensitive T2 mapping technique of the knee for improved cartilage delineation and precise measurement of T2 relaxation times. Study Type Prospective. Phantom/Subjects Phantoms (n = 6) used in this study were designed to mimic the T1 and T2 relaxation times of cartilage and fat. The study cohort comprised healthy volunteers (n = 7) for morphometry and T2 relaxation time measurements. Field Strength/Sequence A high‐resolution isotropic 3D T2 mapping technique that uses sequential T2‐prepared segmented gradient‐recalled echo (Iso3DGRE) images and lipid‐insensitive binomial off‐resonant radiofrequency (RF) excitation (LIBRE) at 3T. Assessment Numerical simulations and phantom experiments were performed to optimize the LIBRE pulse. Phantom studies were carried out to test the accuracy of the technique against reference standard spin‐echo (SE) T2 mapping. Subsequently, T2 maps with and without LIBRE pulses were acquired in knees of healthy volunteers and the T2 relaxation time values in different cartilage compartments were compared. Statistical Tests A two‐tailed paired Student's t‐test was used to compare the average T2 values and the relative standard deviations (inverse measurement of the precision) obtained with and without LIBRE pulses. Results A LIBRE pulse of 1 msec suppressed fat with an RF excitation frequency offset of 1560 Hz and optimal RF excitation angle of 35°. These results were corroborated by phantom and knee experiments. Robust and homogeneous fat suppression was obtained (a fat signal‐to‐noise ratio (SNR) decrease of 86.4 ± 2.4%). In phantoms, T2 values were found in good agreement when comparing LIBRE‐Iso3DGRE with SE (slope 0.93 ± 0.04, intercept 0.11 ± 1.6 msec, R2 >0.99). In vivo, LIBRE excitation resulted in more precise T2 estimation (23.7 ± 7.4%) than normal excitation (30.5 ± 9.9%, P < 0.0001). Data Conclusion Homogeneous LIBRE fat signal suppression was achieved with a total RF pulse duration of 1 msec, allowing for the removal of chemical shift artifacts and resulting in improved cartilage delineation and precise T2 values. Level of Evidence: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:1275–1284.

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“…However, with a combined signal model, the accuracy of T 1 and T 2 are dependent on each other, which may make the results more susceptible to noise, imperfect modeling (e.g., neglecting the efficiency of saturation pulse) 27 and the bias caused by the T 1 relaxation or readout-induced decay after the T 2 -prep pulse. 21,29,30 Previous work, 17 in which a similar T 2 -prep was used for 3D T 2 mapping, showed that comparable T 2 values were observed when either three or four volumes were used for fitting, in both phantoms and in vivo. The inherent high SNR of 3D acquisition makes it possible to use a reduced number of T 1 -weighted volumes for T 1 estimation (e.g., 3) without sacrificing the accuracy.…”

Section: Magnetic Resonance In Medicinementioning

confidence: 97%

A three‐dimensional free‐breathing sequence for simultaneous myocardial T₁ and T₂ mapping

Guo

Chen

Herzka

et al. 2018

Magnetic Resonance in Med

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Purpose: The aim of this study was to develop, test and validate a 3D free‐breathing technique for simultaneous measurement of native myocardial T1 and T2. Methods: The proposed 3D technique acquires five fat‐suppressed electrocardiogram‐triggered respiratory navigator‐gated spoiled gradient echo volumes in an interleaved manner. Four volumes are prepared using a combination of nonselective saturation and T2 preparation. One volume is acquired with fully recovered longitudinal magnetization for accuracy during parametric fitting. Performance of the technique was validated through numerical simulations, phantom experiments and in vivo experiments in 15 healthy human subjects. Results: Simulations and phantom experiments show that the measured T1 and T2 are largely insensitive to heart rate. In vivo whole‐heart maps with a voxel size of 1.5 × 1.5 × 16 mm3 were acquired without parallel imaging within ~ 8 min including respiratory gating efficiency. The in vivo parametric maps were homogeneous (coefficients of variation of left ventricle myocardium were 6.0% ± 0.8% and 10.2% ± 3.4% for T1 and T2 maps, respectively), with an average T1 value of 1470 ± 59.2 ms and T2 value of 41.6 ± 1.8 ms Conclusions: The proposed 3D technique allows for measurement of whole‐heart T1 and T2 with preserved accuracy and precision in a single scan.

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On the accuracy and precision of cardiac magnetic resonance T₂ mapping: A high‐resolution radial study using adiabatic T₂ preparation at 3 T

Abstract: This evaluation of the accuracy and precision of cardiac T mapping characterizes the major vulnerabilities of the technique and will help guide protocol definition of studies that include T mapping. Magn Reson Med 77:159-169, 2017. © 2016 Wiley Periodicals, Inc.

Cited by 17 publications

References 47 publications

Three-Dimensional Self-Navigated T2 Mapping for the Detection of Acute Cellular Rejection After Orthotopic Heart Transplantation

Three-Dimensional Self-Navigated T2 Mapping for the Detection of Acute Cellular Rejection After Orthotopic Heart Transplantation

Simultaneous fat‐free isotropic 3D anatomical imaging and T₂ mapping of knee cartilage with lipid‐insensitive binomial off‐resonant RF excitation (LIBRE) pulses

A three‐dimensional free‐breathing sequence for simultaneous myocardial T₁ and T₂ mapping

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On the accuracy and precision of cardiac magnetic resonance T2 mapping: A high‐resolution radial study using adiabatic T2 preparation at 3 T

Abstract: This evaluation of the accuracy and precision of cardiac T mapping characterizes the major vulnerabilities of the technique and will help guide protocol definition of studies that include T mapping. Magn Reson Med 77:159-169, 2017. © 2016 Wiley Periodicals, Inc.

Cited by 17 publications

References 47 publications

Three-Dimensional Self-Navigated T2 Mapping for the Detection of Acute Cellular Rejection After Orthotopic Heart Transplantation

Three-Dimensional Self-Navigated T2 Mapping for the Detection of Acute Cellular Rejection After Orthotopic Heart Transplantation

Simultaneous fat‐free isotropic 3D anatomical imaging and T2 mapping of knee cartilage with lipid‐insensitive binomial off‐resonant RF excitation (LIBRE) pulses

A three‐dimensional free‐breathing sequence for simultaneous myocardial T1 and T2 mapping

Contact Info

Product

Resources

About

On the accuracy and precision of cardiac magnetic resonance T₂ mapping: A high‐resolution radial study using adiabatic T₂ preparation at 3 T

Simultaneous fat‐free isotropic 3D anatomical imaging and T₂ mapping of knee cartilage with lipid‐insensitive binomial off‐resonant RF excitation (LIBRE) pulses

A three‐dimensional free‐breathing sequence for simultaneous myocardial T₁ and T₂ mapping