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12. Assessment of myocardial lipomatous metaplasia using an optimized out‐of‐phase cine steady‐state free‐precession sequence: Validation and clinical implementation

Author

Azevedo, Clerio F., primary, Jenista, Elizabeth R., additional, Kaolawanich, Yodying, additional, Kim, Han W., additional, Wendell, David C., additional, Alenezi, Fawaz, additional, Chen, Enn‐ling, additional, Parker, Michele A., additional, Judd, Robert M., additional, and Kim, Raymond J., additional

Published
2022
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13. Double spectral attenuated inversion recovery (DSPAIR)—an efficient fat suppression technique for late gadolinium enhancement at 3 tesla

Author

Jenista, Elizabeth R., primary, Jensen, Christoph J., additional, Wendell, David, additional, Spatz, Deneen, additional, Darty, Stephen, additional, Kim, Han W., additional, Parker, Michele, additional, Klem, Igor, additional, Chen, Enn‐Ling, additional, Kim, Raymond J., additional, and Rehwald, Wolfgang G., additional

Published
2021
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14. Noninvasive cineangiography by magnetic resonance global coherent free precession

Author

Rehwald, Wolfgang G, Chen, Enn-Ling, Kim, Raymond J, and Judd, Robert M

Abstract

Cardiovascular disease is primarily diagnosed using invasive X-ray cineangiography. Here we introduce a new concept in magnetic resonance imaging (MRI) that, for the first time, produces similar images noninvasively and without a contrast agent. Protons in moving blood are 'tagged' every few milliseconds as they travel through an arbitrary region in space. Simultaneous with ongoing tagging of new blood, previously tagged blood is maintained in a state of global coherent free precession (GCFP), which allows acquisition of consecutive movie frames as the heart pushes blood through the vascular bed. Body tissue surrounding the moving blood is never excited and therefore remains invisible. In 18 subjects, pulsating blood could be seen flowing through three-dimensional (3D) space for distances of up to 16 cm outside the stationary excitation region. These data underscore that our approach noninvasively characterizes both anatomy and blood flow in a manner directly analogous to invasive procedures., Author(s): Wolfgang G Rehwald [1, 2]; Enn-Ling Chen [1]; Raymond J Kim [1]; Robert M Judd (corresponding author) [1] Since the 1950s, X-ray angiography has been the primary method for [...]

Published
2004
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17. The use of contrast-enhanced magnetic resonance imaging to identify reversible myocardial dysfunction

Author

Kim, Raymond J., Wu, Edwin, Rafael, Allen, Chen, Enn-Ling, Parker, Michele A., Simonetti, Orlando, Klocke, Francis J., Bonow, Robert O., and Judd, Robert M.

Subjects
Magnetic resonance imaging -- Evaluation, Heart attack -- Research, Heart muscle
Abstract

Magnetic resonance imaging of the heart can identify areas of heart muscle that may have reversible damage. This will allow doctors to determine the prognosis of patients who have had a heart attack.

Published
2000

20. A Motion and Flow Insensitive Adiabatic T2-Preparation Module for Cardiac MR Imaging at 3 Tesla

Author

Jenista, Elizabeth R., Rehwald, Wolfgang G., Chen, Enn-Ling, Kim, Han W., Klem, Igor, Parker, Michele A., and Kim, Raymond J.

Subjects
Male, Movement, Magnetic Resonance Imaging, Cine, Reproducibility of Results, Middle Aged, Image Enhancement, Coronary Vessels, Sensitivity and Specificity, Article, Image Interpretation, Computer-Assisted, Humans, Female, Artifacts, Algorithms, Blood Flow Velocity, Magnetic Resonance Angiography
Abstract

A versatile method for generating T2-weighting is a T2-preparation (T2-prep) module, which has been used successfully for cardiac imaging at 1.5T. Although it has been applied at 3T, higher fields (B0 ≥ 3T) can degrade B0 and B1 homogeneity and result in non-uniform magnetization preparation. For cardiac imaging, blood flow and cardiac motion may further impair magnetization preparation. In this study, a novel T2-prep module containing multiple adiabatic B1-insensitive refocusing (BIREF-1) pulses is introduced and compared with three previously described modules (a: composite MLEV4, b: modified BIR-4 (mBIR-4), and c: Silver-Hoult–pair). In the static phantom, the proposed module provided similar or better B0 and B1 insensitivity than the other modules. In human subjects (n=21), quantitative measurement of image signal coefficient of variation (CV), reflecting overall image inhomogeneity, was lower for the proposed module (0.10) than for MLEV4 (0.15, p

Published
2012

25. Prevalence of myocardial scarring in congenital heart disease - comparison between left ventricular pressure and volume overload using a novel black-blood delayed enhancement imaging technique

Author

Huang, Sihong, primary, Campbell, Michael J, additional, Barker, Piers C, additional, Kim, Han W, additional, Wendell, David C, additional, Jenista, Elizabeth, additional, Parker, Michele, additional, Darty, Stephen, additional, Hayes, Brenda D, additional, Chen, Enn-Ling, additional, and Kim, Raymond, additional

Published
2016
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28. Relationship of T2-Weighted MRI Myocardial Hyperintensity and the Ischemic Area-At-Risk

Author

Kim, Han W., primary, Van Assche, Lowie, additional, Jennings, Robert B., additional, Wince, W. Benjamin, additional, Jensen, Christoph J., additional, Rehwald, Wolfgang G., additional, Wendell, David C., additional, Bhatti, Lubna, additional, Spatz, Deneen M., additional, Parker, Michele A., additional, Jenista, Elizabeth R., additional, Klem, Igor, additional, Crowley, Anna Lisa C., additional, Chen, Enn-Ling, additional, Judd, Robert M., additional, and Kim, Raymond J., additional

Published
2015
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29. Suppression of ghost artifacts arising from long T1 species in segmented inversion-recovery imaging.

Author

Jenista, Elizabeth R., Rehwald, Wolfgang G., Chaptini, Nayla H., Kim, Han W., Parker, Michele A., Wendell, David C., Chen, Enn ‐ ling, and Kim, Raymond J.

Abstract

Purpose We demonstrate an improved segmented inversion-recovery sequence that suppresses ghost artifacts arising from tissues with long T1 ( > 1.5 s). Theory and Methods Long T1 species such as pericardial fluid can create bright ghost artifacts in segmented, inversion-recovery MRI because of oscillations in longitudinal magnetization between segments. A single dummy acquisition at the beginning of the sequence can reduce oscillations; however, its effectiveness in suppressing long T1 artifacts is unknown. In this study, we systematically evaluated several test sequences, including a prototype (saturation post-pulse readout to eliminate spurious signal: SPPRESS) in simulations, phantoms, and patients. Results SPPRESS reduced artifact signal 90% ± 25% and 74% ± 28% compared with Control and Single-Dummy methods in phantoms. SPPRESS performed well at 1.5 Tesla (T) and 3T, with steady-state free precession (SSFP) and fast low-angle shot (FLASH) readout, with conventional and phase-sensitive reconstruction, and over a range of physiologic heart rates. A review of 100 consecutive clinical cardiac MRI scans revealed large fluid collections (eg, regions with long T1) in 14% of patients. In a prospectively enrolled cohort of 16 patients with visible long T1 fluids, SPPRESS appreciably reduced artifacts in all cases compared with Control and Single-Dummy methods. Conclusion We developed and validated a new robust method, SPPRESS, for reducing artifacts due to long T1 species across a wide range of imaging and physiologic conditions. Magn Reson Med 78:1442-1451, 2017. © 2016 International Society for Magnetic Resonance in Medicine. [ABSTRACT FROM AUTHOR]

Published
2017
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37. Nuclear magnetic relaxation of water protons in protein solutions and tissue: Insights into mechanism and application in MRI using low-frequency dispersion

Author

Chen, Enn-Ling and Chen, Enn-Ling

Abstract

As demonstrated by bulk water proton T$\sb{1\rho}$ dispersion results, protein crosslinking revealed the existence of very slow motion (10 $\mu$sec $\le\tau\sb{\rm c}\le10$ msec) in solution, presumably previously concealed by rapid tumbling motion of the protein molecules. Rates of direct chemical exchange of protons between solvent molecules and protein, characterized by a time scale within the T$\sb{1\rho}$-sensitive range, was likely not necessary for the observed proton T$\sb{1\rho}$ dispersion above 10 kHz $\rm\gamma B\sb1$ in tissue and solutions of crosslinked protein, as inferred from their relative independence from solvent substitution with DMSO and from pH variations. Power law behavior was characterized for T$\sb{1\rho}$ dispersion acquired in tissues and crosslinked protein and were found to be associated with parameter values similar to those found in tissue T$\sb1$ dispersion. However, soluble proteins do not follow the power law, indicating crosslinked proteins rather than soluble proteins are good model for tissue, a characteristic more apparent at low frequencies since crosslinking altered T$\sb2$ and T$\sb{1\rho}$ significantly more than T$\sb1.$ A mechanism of relaxation not previously considered for tissues is proposed here and found to be able to predict rates of relaxation (T$\sb1)$ utilizing data (T$\sb{1\rho})$ acquired at frequencies 3 orders of magnitude lower. Results of analysis suggest that the proposed mechanism can account for relaxation data acquired here in tissue and crosslinked protein solutions. Finally, application of T$\sb{1\rho}$ as a contrast mechanism is demonstrated for the heart in the study of acute infarcts.

Published
1998

46. Motion and flow insensitive adiabatic T2-preparation module for cardiac MR imaging at 3 tesla.

Author

Jenista, Elizabeth R., Rehwald, Wolfgang G., Chen, Enn‐Ling, Kim, Han W., Klem, Igor, Parker, Michele A., and Kim, Raymond J.

Abstract

A versatile method for generating T2-weighting is a T2-preparation module, which has been used successfully for cardiac imaging at 1.5T. Although it has been applied at 3T, higher fields ( B0 ≥ 3T) can degrade B0 and B1 homogeneity and result in nonuniform magnetization preparation. For cardiac imaging, blood flow and cardiac motion may further impair magnetization preparation. In this study, a novel T2-preparation module containing multiple adiabatic B1-insensitive refocusing pulses is introduced and compared with three previously described modules [(a) composite MLEV4, (b) modified BIR-4 (mBIR-4), and (c) Silver-Hoult-pair]. In the static phantom, the proposed module provided similar or better B0 and B1 insensitivity than the other modules. In human subjects ( n = 21), quantitative measurement of image signal coefficient of variation, reflecting overall image inhomogeneity, was lower for the proposed module (0.10) than for MLEV4 (0.15, P < 0.0001), mBIR-4 (0.27, P < 0.0001), and Silver-Hoult-pair (0.14, P = 0.001) modules. Similarly, qualitative analysis revealed that the proposed module had the best image quality scores and ranking (both, P < 0.0001). In conclusion, we present a new T2-preparation module, which is shown to be robust for cardiac imaging at 3T in comparison with existing methods. Magn Reson Med 70:1360-1368, 2013. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Published
2013
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47. Contrast-enhanced magnetic resonance imaging of myocardium at risk Distinction between reversible and irreversible injury throughout infarct healing

Author

Fieno, David S, Kim, Raymond J, Chen, Enn-Ling, Lomasney, Jon W, Klocke, Francis J, and Judd, Robert M

Abstract

OBJECTIVESWe sought to determine the relationship of delayed hyperenhancement by contrast magnetic resonance imaging (MRI) to viable and nonviable myocardium within the region at risk throughout infarct healing.BACKGROUNDThe relationship of delayed MRI contrast enhancement patterns to injured but viable myocardium within the ischemic bed at risk has not been established.METHODSWe compared in vivo and ex vivo MRI contrast enhancement to histopathologic tissue sections encompassing the entire left ventricle in dogs (n = 24) subjected to infarction with (n = 12) and without (n = 12) reperfusion at 4 h, 1 day, 3 days, 10 days, 4 weeks and 8 weeks. In vivo MR imaging was performed 30 min after contrast injection.RESULTSThe sizes and shapes of in vivo myocardial regions of elevated image intensity (828 ± 132% of remote) were the same as those observed ex vivo (241 slices, r = 0.99, bias = 0.05 ± 1.6% of left ventricle [LV]). Comparison of ex vivo MRI to triphenyltetrazolim chloride–stained sections demonstrated that the spatial extent of hyperenhancement was the same as the spatial extent of infarction at every stage of healing (510 slices, lowest r = 0.95, largest bias = 1.7 ± 2.9% of LV). Conversely, hyperenhanced regions were smaller than the ischemic bed at risk defined by fluorescent microparticles at every stage of healing (239 slices, 35 ± 24% of risk region, p < 0.001). Image intensities of viable myocardium within the risk region were the same as those of remote, normal myocardium (102 ± 9% of remote, p = NS).CONCLUSIONSDelayed contrast enhancement by MRI distinguishes between viable and nonviable regions within the myocardium at risk throughout infarct healing.

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48. Motion Robust Segmented Delayed Enhancement MRI by Partially Reversed ReOrdering for GeneRal SupprESSion of Motion Induced Variable Errors

Author

Rehwald, Wolfgang, primary, Rojas, Rafael, additional, Mena, Nestor, additional, Seward, Ryan, additional, Gamoneda, George, additional, Dement, Jeana, additional, Jenista, Elizabeth, additional, Wendell, David, additional, Kim, Han, additional, Chen, Enn-Ling, additional, Klem, Igor, additional, Kimbrell, Vera, additional, and Kim, Raymond, additional

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50. Suppression of ghost artifacts arising from long T 1 species in segmented inversion-recovery imaging.

Author

Jenista ER, Rehwald WG, Chaptini NH, Kim HW, Parker MA, Wendell DC, Chen EL, and Kim RJ

Subjects
Artifacts, Contrast Media, Gadolinium, Heart diagnostic imaging, Humans, Phantoms, Imaging, Image Processing, Computer-Assisted methods, Magnetic Resonance Imaging methods
Abstract

Purpose: We demonstrate an improved segmented inversion-recovery sequence that suppresses ghost artifacts arising from tissues with long T 1 ( > 1.5 s)., Theory and Methods: Long T 1 species such as pericardial fluid can create bright ghost artifacts in segmented, inversion-recovery MRI because of oscillations in longitudinal magnetization between segments. A single dummy acquisition at the beginning of the sequence can reduce oscillations; however, its effectiveness in suppressing long T 1 artifacts is unknown. In this study, we systematically evaluated several test sequences, including a prototype (saturation post-pulse readout to eliminate spurious signal: SPPRESS) in simulations, phantoms, and patients., Results: SPPRESS reduced artifact signal 90% ± 25% and 74% ± 28% compared with Control and Single-Dummy methods in phantoms. SPPRESS performed well at 1.5 Tesla (T) and 3T, with steady-state free precession (SSFP) and fast low-angle shot (FLASH) readout, with conventional and phase-sensitive reconstruction, and over a range of physiologic heart rates. A review of 100 consecutive clinical cardiac MRI scans revealed large fluid collections (eg, regions with long T 1 ) in 14% of patients. In a prospectively enrolled cohort of 16 patients with visible long T 1 fluids, SPPRESS appreciably reduced artifacts in all cases compared with Control and Single-Dummy methods., Conclusion: We developed and validated a new robust method, SPPRESS, for reducing artifacts due to long T 1 species across a wide range of imaging and physiologic conditions. Magn Reson Med 78:1442-1451, 2017. © 2016 International Society for Magnetic Resonance in Medicine., (© 2016 International Society for Magnetic Resonance in Medicine.)

Published
2017
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