Keywords: Myocardium, Cardiovascular

Motivation: Prognostic value of radiomic features extracted from CMR  cine image remains to be investigated.

Goal(s): To evaluate the prognostic value of radiomic features derived from cine images in patients with ST-segment elevation myocardial infarction (STEMI).

Approach: Radiomic features were extracted from CMR cine images on STEMI patients, and LASSO -Cox regression used to select predictive features for MACE. Cox regression was applied to build models.

Results: RAD score provided an incremental prognostic value above baseline clinical factors and LVEF (C-index 0.78 vs 0.69; p=0.002) and outperformed the addition of CMR markers of infarct injury  (C-index: 0.78 vs 0.69, p<0.001).

Impact: Radiomic features provide incremental prognostic value to clinical and infarct size in the prediction of MACE, which would promote the development of the prognostic assessment with non-contrast enhanced CMR.

Keywords: Myocardium, Perfusion

Motivation: This research advances quantitative analysis of myocardial perfusion MRI, potentially enhancing the precision of coronary microvascular disease diagnosis.

Goal(s): To establish a novel spatiotemporal radiomics and fractal analysis approach, assessing myocardial perfusion patterns and complexity throughout all temporal frames of stress MRI.

Approach: Employing free-breathing stress myocardial perfusion MRI, we utilized a comprehensive pixel-by-pixel spatiotemporal feature extraction, alongside phase-specific analysis, to derive global and segmental perfusion insights.

Results: Preliminary results indicate our method's efficacy in motion correction and feature extraction, offering a new quantitative perspective on myocardial perfusion, potentially relevant for CMD assessment.

Impact: The study introduces a framework that quantitatively captures myocardial perfusion patterns, potentially paving the way for enhanced diagnostic methods in coronary microvascular disease and facilitating a more precise approach to patient assessment. 

Keywords: Myocardium, Perfusion, SMS, CAIPIRINHA

Motivation: Clinical cardiac perfusion captures a limited number of slices sequentially within each heartbeat, causing incomplete left ventricle coverage and potential quantification variability due to different cardiac phases.

Goal(s): To image multiple slices simultaneously thereby reducing quantification variability and improve heart coverage.

Approach: We apply highly accelerated Simultaneous Multi-slice Imaging via Linear phase modulated Extended field of view (SMILE) acquisition and reconstruction framework to cardiac perfusion.

Results: With a high multiband factor and accelerated rate, SMILE perfusion achieve whole heart coverage and allows for more slices to be in the same cardiac phase. Retrospective and prospective experiments validated its good quality.

Impact: The proposed methods can significantly enhance the heart coverage of clinical cardiac perfusion and potentially benefit reducing variability in quantitative perfusion assessment.

Keywords: Myocardium, Pulse Sequence Design, myocardial blood volume, ferumoxytol

Motivation: Intramyocardial blood volume (iMBV) variations during cardiac cycle can be an important marker for detecting ischemic heart disease. However, quantifying the change in iMBV from diastole to systole under MRI has challenges such as through-plane motion or in-flow of unsaturated spins.

Goal(s): Our goal is to perform accurate quantification of iMBV variations from diastole to systole.

Approach: We developed a novel hybrid 3D/2D pulse sequence with continuous golden-angle radial acquisition to suppress the confounding factors for distinguishing diastolic and systolic iMBV.

Results:  Our approach successfully showed that cyclic variations in iMBV can be correctly quantified under ferumoxytol-enhanced MRI.

Impact: We introduced, for the first time, an approach to quantify cyclic systolic and diastolic intramyocardial blood volume variations at rest on a clinical scanner with ferumoxytol-enhanced imaging. Our method has the potential to be used for detecting ischemic heart disease

Keywords: Myocardium, Cardiovascular

Motivation: Intramyocardial hemorrhage (IMH) staging can serve as a valuable reference point when exploring treatment options for this condition, but methodsfor detecting IMH staging has not been fully examined.

Goal(s): This study investigated whether BOOST, a novel iNAV-based free-breathing, multi-contrast 3D whole-heart MRI sequence could detect and stage IMH.

Approach: The efficacy of BOOST in diagnosing and staging IMH were compared with the performances of conventional T2* sequences.

Results: BOOST, used for IMH detection at 3T, demonstrates superior sensitivity and specificity, along with good quantitative consistency, relative to T2* alone. Additionally, BOOST has substantial potential for IMH staging.

Impact: The BOOST sequence can be used for future IMH staging, which will facilitate precise multi-dimensional IMH assessment, ultimately enabling accurate and targeted IMH treatment.

Keywords: Myocardium, Quantitative Imaging, Tissue characterization, myocardial infarction, black-blood imaging

Motivation: Bright-blood sequences are used to retrieve information about cardiac anatomy and function, while black-blood sequences have been exploited for focal scar detection. Moreover, contrast agent-free T1-rho (T1ρ) mapping has shown promise for scar quantification, particularly of diffuse nature.

Goal(s): We propose SPOT1ρ, a single-click joint bright-blood, black-blood, and T1ρ mapping sequence providing improved scar localization, detection, and quantification.

Approach: The proposed SPOT1ρ was compared to reference sequences in phantom and patients (three myocardial infarctions, one cardiac amyloidosis and one healthy control).

Results: Excellent correlation was observed between SPOT1ρ and reference T1ρ values, along with co-registered bright- and black-blood images in phantom and patients.

Impact: The proposed single-click SPOT1ρ permits easier and faster planning for MR technicians, more comfort for the patient, promoted by fewer breath-holds, and a simplified interpretation for the radiologists, through co-registered, qualitative, and quantitative images.

Keywords: Arrhythmia, Tissue Characterization, ventricular tachycardia, catheter ablation

Motivation: Catheter ablation is clinically indicated for targeting re-entrant ventricular tachycardia (VT) in patients with an implantable cardioverter defibrillator (ICD), but its 1-year VT recurrence rate is high. We hypothesize that 3D wideband LGE is useful for guiding VT ablation.

Goal(s): To determine whether 3D wideband LGE correlates with electroanatomic mapping (EAM) in ICD patients.

Approach: To develop a 3D isotropic wideband LGE pulse sequence and validate it against EAM in ICD patients.

Results: While myocardial scars and gray-zones in LGE correlated with the low voltage areas (<1.5 mV) in EAM, mid-myocardial non-ischemic scars was not correlated between LGE and EAM. 

Impact: High-resolution 3D isotropic wideband LGE has potential to increase the success rate of catheter ablation for re-entrant ventricular tachycardia in patients with an implantable cardioverter defibrillation, as well as decrease the procedural time by providing a roadmap prior to ablation.

Keywords: Inflammation, Infiltration, Cardiovascular, CMR

Motivation: Microvascular obstruction (MVO) after primary percutaneous coronary intervention (pPCI) is identifed as an independent risk factor for poor prognosis in patients with acute myocardial infarction (AMI). However, the clinical implications of Epicardial adipose tissue (EAT) in microvascular obstruction formation in patients with ST-segment elevation myocardial infarction (STEMI) remain unclear.

Goal(s): This study aimed to evaluate the correlation between EAT and MVO volume detected by CMR in STEMI patients.

Approach: Cardiac magnetic resonance (CMR) has emerged as the gold standard technique to detect the extent of MVO and evaluate EAT volume.

Results: Left atrioventricular EAT mass index is an independent predictor of MVO.

Impact: Measurement of EAT using CMR could be used for risk stratification and may be a promising target in developing new therapies to reduce myocardial reperfusion injury in patients with STEMI.

Keywords: Heart Failure, Fat, T1 Mapping

Motivation: Proinflammatory epicardial adipose tissue (EAT) contributes to heart failure (HF). MRI fatty acid composition (FAC) and T₁ of EAT may distinguish proinflammatory vs. healthy EAT. Applying separate FAC and T₁ mapping sequences is time consuming, motivating the development of accelerated methods.

Goal(s): Our goal was to create an accelerated joint EAT FAC and T₁-mapping method (FACT) for use in mice at 9.4 T.

Approach: An inversion-recovery multi-echo sequence and model-based mapping method was developed with acceleration along orthogonal time dimensions. 

Results: Results demonstrate feasibility of the FACT method with approximately rate 12 acceleration. 

Impact: The FACT method efficiently and accurately determines both EAT fat composition and T₁ and could be used in-vivo to investigate mechanisms and efficacy of novel therapies targeting proinflammatory EAT in the context of metabolic heart disease.

Keywords: Heart Failure, Cardiovascular

Motivation: The impact of high-altitude hypobaric hypoxia on myocardial infarction cardioprotection is a subject of ongoing research in cardiovascular studies. 

Goal(s): We aimed to assess the potential protective effects of high-altitude hypobaric hypoxia in a rat model of MI using 7.0T CMR strain analysis.

Approach: We used rats model and transporting some rats to an elevation of 4,250 meters, while control rats remained at 500 meters. Then surgically induced myocardial infarctions in the rats at each elevation.

Results: The finding was that rats with MI living at high altitude had significantly better preservation of heart function compared to control rats living at 500 meters. 

Impact: The outcomes of this study hold significance for the management of patients at risk of MI, particularly those residing in high-altitude environments or experiencing hypobaric hypoxia. Identifying the cardioprotective effects may result in the development of new therapeutic strategies.