a-magnetic-resonance-imaging-based-computational-protocol-for

A Magnetic Resonance Imaging-based Computational Protocol for Analysis of Plaque Morphology and Hemodynamics in Patients with Carotid Artery Stenosis

Current assessment and management of internal carotid artery (ICA) stenosis is based on the estimation of percentage stenosis via duplex ultrasound (DUS) ...

Cedars Sinai Medical Center

To perform fast 3D steady-state CEST (ss-CEST) imaging using MR Multitasking.

Whole-brain steady-state CEST at 3 T using MR Multitasking.

The aim of this study is to simultaneously quantify T1/T2 across three slices of the left-ventricular myocardium without breath-holds or ECG monitoring, all within a 3 min scan. Radial simultaneous multi-slice (SMS) encoding, self-gating, and image reconstruction was incorporated into the cardiovascular magnetic resonance (CMR) Multitasking framework to simultaneously image three short-axis slices. A T2prep-IR FLASH sequence with two flip angles was designed and implemented to allow B1+-robust T1 and T2 mapping. The proposed Multitasking-SMS method was validated in a standardized phantom and 10 healthy volunteers, comparing T1 and T2 measurements and scan-rescan repeatability against corresponding reference methods in one layer of phantom vials and in 16 American Heart Association (AHA) myocardial segments. In phantom, Multitasking-SMS T1/T2 measurements showed substantial correlation (  > 0.996) and excellent agreement [intraclass correlation coefficients (ICC) ≥ 0.999)] with reference measurements. In healthy volunteers, Multitasking-SMS T1/T2 maps reported similar myocardial T1/T2 values (1,215 ± 91.0/41.5 ± 6.3 ms) to the reference myocardial T1/T2 values (1,239 ± 67.5/42.7 ± 4.1 ms), with  = 0.347 and  = 0.296, respectively. Bland-Altman analyses also demonstrated good  repeatability in both the multitasking and references, with segment-wise coefficients of variation of 4.7% (multitasking T1), 8.9% (multitasking T2), 2.4% [modified look-locker inversion recovery (MOLLI)], and 4.6% (T2-prep FLASH), respectively. In summary, multitasking-SMS is feasible for free-breathing, non-ECG, myocardial T1/T2 quantification in 16 AHA segments over 3 short-axis slices in 3 min. The method shows the great potential for reducing exam time for quantitative CMR without ECG or breath-holds.

Simultaneous Multi-Slice Cardiac MR Multitasking for Motion-Resolved, Non-ECG, Free-Breathing T1-T2 Mapping.

To develop a free-breathing, non-electrocardiogram technique for simultaneous myocardial T , T , T *, and fat-fraction (FF) mapping in a single scan.

Free-breathing, non-ECG, simultaneous myocardial T , T , T *, and fat-fraction mapping with motion-resolved cardiovascular MR multitasking.

To develop a novel 3D abdominal CEST MRI technique at 3 T using MR multitasking, which enables entire-liver coverage with free-breathing acquisition.

Free-breathing 3D CEST MRI of human liver at 3.0 T.

 mapping is becoming a staple magnetic resonance imaging method for diagnosing myocardial diseases such as ischemic cardiomyopathy, hypertrophic cardiomyopathy, myocarditis, and more. Clinically, most  mapping sequences acquire a single slice at a single cardiac phase across a 10 to 15-heartbeat breath-hold, with one to three slices acquired in total. This leaves opportunities for improving patient comfort and information density by acquiring data across multiple cardiac phases in free-running acquisitions and across multiple respiratory phases in free-breathing acquisitions. Scanning in the presence of cardiac and respiratory motion requires more complex motion characterization and compensation. Most clinical mapping sequences use 2D single-slice acquisitions; however newer techniques allow for motion-compensated reconstructions in three dimensions and beyond. To further address confounding factors and improve measurement accuracy,  maps can be acquired jointly with other quantitative parameters such as , , fat fraction, and more. These multiparametric acquisitions allow for constrained reconstruction approaches that isolate contributions to  from other motion and relaxation mechanisms. In this review, we examine the state of the literature in motion-corrected and motion-resolved  mapping, with potential future directions for further technical development and clinical translation.

Motion-compensated T mapping in cardiovascular magnetic resonance imaging: a technical review.

High-intensity plaque (HIP) on magnetic resonance imaging (MRI) has been documented as a powerful predictor of periprocedural myocardial injury (PMI) following percutaneous coronary intervention (PCI). Despite the recent proposal of three-dimensional HIP quantification to enhance the predictive capability, the conventional pulse sequence, which necessitates the separate acquisition of anatomical reference images, hinders accurate three-dimensional segmentation along the coronary vasculature. Coronary atherosclerosis T-weighted characterization (CATCH) enables the simultaneous acquisition of inherently coregistered dark-blood plaque and bright-blood coronary artery images. We aimed to develop a novel HIP quantification approach using CATCH and to ascertain its superior predictive performance compared to the conventional two-dimensional assessment based on plaque-to-myocardium signal intensity ratio (PMR).

Rapid three-dimensional quantification of high-intensity plaques from coronary atherosclerosis T-weighted characterization to predict periprocedural myocardial injury.

The rotating Cartesian k-space multiphase steady-state imaging with contrast (ROCK-MUSIC) pulse sequence enables acquisition of whole-heart, cardiac phase-resolved images in pediatric congenital heart disease (CHD) without reliance on the ventilator gating signal. Multidimensional reconstruction with low rank tensor (LRT) has shown promise for resolving complex cardiorespiratory motion.

Ferumoxytol-Enhanced 5D Multiphase Steady-State Imaging Using Rotating Cartesian K-Space With Low-Rank Reconstruction for Pediatric Congenital Heart Disease.

Purpose To clarify the predominant causative plaque constituent for periprocedural myocardial injury (PMI) following percutaneous coronary intervention:  erythrocyte-derived materials, indicated by a high plaque-to-myocardium signal intensity ratio (PMR) at coronary atherosclerosis T1-weighted characterization (CATCH) MRI, or  lipids, represented by a high maximum 4-mm lipid core burden index (maxLCBI) at near-infrared spectroscopy intravascular US (NIRS-IVUS). Materials and Methods This retrospective study included consecutive patients who underwent CATCH MRI before elective NIRS-IVUS-guided percutaneous coronary intervention at two facilities. PMI was defined as post-percutaneous coronary intervention troponin T values greater than five times the upper reference limit. Multivariable analysis was performed to identify predictors of PMI. Finally, the predictive capabilities of MRI, NIRS-IVUS, and their combination were compared. Results A total of 103 lesions from 103 patients (median age, 72 years [IQR, 64-78]; 78 male patients) were included. PMI occurred in 36 lesions. In multivariable analysis, PMR emerged as the strongest predictor ( = .001), whereas maxLCBI was not a significant predictor ( = .07). When PMR was excluded from the analysis, maxLCBI emerged as the sole independent predictor ( = .02). The combination of MRI and NIRS-IVUS yielded the largest area under the receiver operating curve (0.86 [95% CI: 0.64, 0.83]), surpassing that of NIRS-IVUS alone (0.75 [95% CI: 0.64, 0.83];  = .02) or MRI alone (0.80 [95% CI: 0.68, 0.88];  = .30). Conclusion Erythrocyte-derived materials in plaques, represented by a high PMR at CATCH MRI, were strongly associated with PMI independent of lipids. MRI may play a crucial role in predicting PMI by offering unique pathologic insights into plaques, distinct from those provided by NIRS.  Coronary Plaque, Periprocedural Myocardial Injury, MRI, Near-Infrared Spectroscopy Intravascular US  © RSNA, 2024.

Coronary Plaque Characterization with T1-weighted MRI and Near-Infrared Spectroscopy to Predict Periprocedural Myocardial Injury.

To shorten CEST acquisition time by leveraging Z-spectrum undersampling combined with deep learning for CEST map construction from undersampled Z-spectra.

Accelerated CEST imaging through deep learning quantification from reduced frequency offsets.

Purpose To evaluate the performance of a high-dynamic-range quantitative susceptibility mapping (HDR-QSM) cardiac MRI technique to detect intramyocardial hemorrhage (IMH) and quantify iron content using phantom and canine models. Materials and Methods A free-running whole-heart HDR-QSM technique for IMH assessment was developed and evaluated in calibrated iron phantoms and 14 IMH female canine models. IMH detection and iron content quantification performance of this technique was compared with the conventional iron imaging approaches, R2*(1/T2*) maps, using measurements from ex vivo imaging as the reference standard. Results Phantom studies confirmed HDR-QSM's accurate iron content quantification and artifact mitigation ability by revealing a strong linear relationship between iron concentration and QSM values (, 0.98). In in vivo studies, HDR-QSM showed significantly improved image quality and susceptibility homogeneity in nonaffected myocardium by alleviating motion and off-resonance artifacts (HDR-QSM vs R2*: coefficient of variation, 0.31 ± 0.16 [SD] vs 0.73 ± 0.36 [ < .001]; image quality score [five-point Likert scale:], 3.58 ± 0.75 vs 2.87 ± 0.51 [ < .001]). Comparison between in vivo susceptibility maps and ex vivo measurements showed higher performance of HDR-QSM compared with R2* mapping for IMH detection (area under the receiver operating characteristic curve, 0.96 vs 0.75;  < .001) and iron content quantification (, 0.71 vs 0.14). Conclusion In a canine model of IMH, the fast and free-running cardiac QSM technique accurately detected IMH and quantified intramyocardial iron content of the entire heart within 5 minutes without requiring breath holding.  High-Dynamic-Range Quantitative Susceptibility Mapping, Myocardial Infarction, Intramyocardial Hemorrhage, MRI  ©RSNA, 2024.

Accurate Intramyocardial Hemorrhage Assessment with Fast, Free-running, Cardiac Quantitative Susceptibility Mapping.

To develop a deep subspace learning network that can function across different pulse sequences.

Generalizable, sequence-invariant deep learning image reconstruction for subspace-constrained quantitative MRI.

Multiparametric MRI (mpMRI) as a non-invasive imaging tool is important in prostate cancer (PCa) detection and localization. Combined with radiomics analysis, features extracted from mpMRI have been utilized to predict PCa aggressiveness. T2 mapping provides quantitative information in PCa diagnoses but is not routinely available in clinical practice. Previous work from our group developed a deep learning-based method to estimate T2 maps from clinically acquired T1- and T2-weighted images. This study aims to evaluate the added value of the estimated T2 map by combining it with conventional T2-weighted images for detecting clinically significant PCa (csPCa).

Retrospectively Quantified T2 Improves Detection of Clinically Significant Peripheral Zone Prostate Cancer.

Coronary computed tomography angiography (CCTA) and magnetic resonance imaging (MRI) can predict periprocedural myocardial injury (PMI) after percutaneous coronary intervention (PCI). We aimed to investigate whether integrating MRI with CCTA, using the latest imaging and quantitative techniques, improves PMI prediction and to explore a potential hybrid CCTA-MRI strategy.

Hybrid strategy of coronary atherosclerosis characterization with T1-weighted MRI and CT angiography to non-invasively predict periprocedural myocardial injury.

Article	Year
Whole-brain steady-state CEST at 3 T using MR Multitasking. Magnetic resonance in medicine\| PubMed ID: 34843114	2022
Simultaneous Multi-Slice Cardiac MR Multitasking for Motion-Resolved, Non-ECG, Free-Breathing T1-T2 Mapping. Frontiers in cardiovascular medicine\| PubMed ID: 35310971	2022
Free-breathing, non-ECG, simultaneous myocardial T , T , T *, and fat-fraction mapping with motion-resolved cardiovascular MR multitasking. Magnetic resonance in medicine\| PubMed ID: 35713184	2022
Free-breathing 3D CEST MRI of human liver at 3.0 T. Magnetic resonance in medicine\| PubMed ID: 36161668	2023
Motion-compensated T mapping in cardiovascular magnetic resonance imaging: a technical review. Frontiers in cardiovascular medicine\| PubMed ID: 37790594	2023
Rapid three-dimensional quantification of high-intensity plaques from coronary atherosclerosis T-weighted characterization to predict periprocedural myocardial injury. Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance\| PubMed ID: 38237903	2024
Ferumoxytol-Enhanced 5D Multiphase Steady-State Imaging Using Rotating Cartesian K-Space With Low-Rank Reconstruction for Pediatric Congenital Heart Disease. Journal of magnetic resonance imaging : JMRI\| PubMed ID: 39143805	2025
Coronary Plaque Characterization with T1-weighted MRI and Near-Infrared Spectroscopy to Predict Periprocedural Myocardial Injury. Radiology. Cardiothoracic imaging\| PubMed ID: 39145734	2024
Accelerated CEST imaging through deep learning quantification from reduced frequency offsets. Magnetic resonance in medicine\| PubMed ID: 39270056	2025
Accurate Intramyocardial Hemorrhage Assessment with Fast, Free-running, Cardiac Quantitative Susceptibility Mapping. Radiology. Cardiothoracic imaging\| PubMed ID: 39665631	2024
Generalizable, sequence-invariant deep learning image reconstruction for subspace-constrained quantitative MRI. Magnetic resonance in medicine\| PubMed ID: 39834093	2025
Retrospectively Quantified T2 Improves Detection of Clinically Significant Peripheral Zone Prostate Cancer. Cancers\| PubMed ID: 39941750	2025
Hybrid strategy of coronary atherosclerosis characterization with T1-weighted MRI and CT angiography to non-invasively predict periprocedural myocardial injury. European heart journal. Cardiovascular Imaging\| PubMed ID: 40241659	2025

Hsu-Lei Lee

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