Keywords: Atherosclerosis, Heart

Motivation: Compared with primary percutaneous coronary intervention (PPCI), it is not known whether patients with ST-elevation myocardial infarction (STEMI) benefit from thrombolysis prior to PCI within 120 minutes of symptom onset.

Goal(s): This study was to compare the short-term performance between STEMI patients with and without a single bolus recombinant staphylokinase (r-SAK) prior to PCI by Cardiac Magnetic Resonance (CMR) imaging.

Approach: The global and segmental [mainly focusing on LGE+ segment (transmural extent >50%)] CMR parameters were compared between r-SAK group and control group. 

Results: Patients can benefit from thrombolysis prior to PCI with better myocardial function and smaller extent of edema.

Impact: This study investigated the short-term advantages of adjunctive thrombolysis with r-SAK for STEMI patients undergoing PCI. A single bolus r-SAK intravenously prior to PCI for STEMI improves myocardial function and reduces the extent of edema.

Keywords: Myocardium, Myocardium, myocardial delayed enhancement, deep learning reconstruction

Motivation: Myocardial delayed enhanced (MDE) imaging is the gold standard for assessing myocardial viability in various cardiac pathologies. However, long breath-hold is needed for MDE to achieve reasonable spatial resolution, hampering its utility for patients with insufficient breath-hold capability.

Goal(s): The goal for this study is to optimize a variable-density undersampling pattern to achieve highly accelerated MDE imaging combined with deep learning reconstruction. 

Approach: The optimization was conducted with phantom and post-contrast in vivo studies.

Results: The optimized undersampling pattern and deep learning reconstruction enable 4-time acceleration for phase-sensitive MDE imaging with comparable image quality to the reference image.

Impact: The optimized variable-density undersampling pattern combined with deep learning reconstruction can potentially expand the clinical utility of MDE imaging to especially patient with insufficient breath-hold capability, and improve the patient comfort.

Keywords: Machine Learning/Artificial Intelligence, Cardiovascular, Scan planning, Cardiovascular MR acquisition, Computational geometry

Motivation: Manual planning for cardiac MRI (CMR) involving complex oblique views is time-consuming and introduces intra- and inter-technologist variability.

Goal(s): To develop a fast and robust model that automatically predicts the standard CMR views from a 3D survey scan (SS) image. 

Approach: We use a deep learning (DL) based approach to map the 3D-SS image to four standard CMR using an instance segmentation strategy that identifies all planes followed by a finetuning strategy, which potentially offers improved robustness.  

Results: We achieved mean angulation and offset errors of 3.72±2.1 degrees and 2.36±1.8 mm, respectively across four standard CMR views averaged across 100 test subjects.

Impact: Plane estimation as instance segmentation problem understands the spatial conformations of the planes and can adapt to various heart shapes and sizes and can go a long way in reducing intra- and inter-technologist variability and more importantly reducing scanning time.

Keywords: Flow, Cardiovascular, Exercise, diastolic function

Motivation: Exercise testing is important in evaluation of diastolic dysfunction but there is little use of exercise for diagnosis.

Goal(s): Test if MR phase-contrast and cine techniques can identify changes in E, A, and e’ with hand-grip exercise.

Approach: Five healthy subjects underwent diastolic function evaluation by MRI, during isometric handgrip exercise.  E, A and e’ were evaluated.

Results: In this group, E/A decreased with exercise, and recovered after a period of rest. Isometric handgrip exercise is promising approach for revealing diastolic dysfunction in patients.

Impact: Isometric hand-grip exercise may be a useful tool in exercise cardiac MRI  for diagnosis in patients with heart failure with preserved ejection fraction.

Keywords: Myocardium, Cardiovascular, SWIN, ESPIRiT, Resnet, CINE

Motivation: Cardiac CINE MRI is used clinically for characterizing heart morphology and function, but requires multiple breath-holds to minimize motion artifacts from respiration.

Goal(s): Deep learning based ESPIRiT (DL-ESPIRiT) is able to reconstruct dynamic MRI data with high reconstruction accuracy. However, the method still has difficulty resolving fine anatomic structures. We aim to improve reconstruction accuracy using newer transformer architecture.

Approach: We replace the ResNet deep learning backbone by a modified Swin Image Restoration network (SwinIR) with video Swin transformers, called DL-ESPIRiT VSwinIR

Results: DL-ESPIRiT VSwinIR has substantially improved reconstruction accuracy and can accelerate acquisitions by up to 20x.

Impact: Fast CINE acquisitions using our DL-ESPIRiT VSwinIR may enable multiple CINE slices to be acquired in a  shortened breath-hold, which will allow heart morphology and function assessment in patients with difficulty breath-holding or following instructions.

Keywords: Myocardium, Cardiovascular, 3D real-time imaging

Motivation: To achieve high-temporal-resolution 3D whole-heart MR cine without the need for ECG, allow direct visualization of physiological motions, and assess cardiac function in clinical practice.

Goal(s): To attain 3D multi-slice whole-heart real-time imaging with <50 ms temporal resolution, while preserving adequate spatial resolution for cardiac functional analysis.

Approach: We employed golden-angle rotated spiral-in/out trajectory with 32× acceleration, and randomized variable density k_z phase-encoding in the bSSFP sequence, and harnessed an iterative reconstruction algorithm.

Results: We attained a groundbreaking achievement in advancing MRI capabilities, obtaining an ECG-free 3D real-time cardiac cine with complete 12-slice whole-heart coverage and an impressive sub-50 ms temporal resolution.

Impact: We've employed advanced techniques to triumph over MRI's historical disadvantage of slower acquisition compared to other modalities. Pioneering a groundbreaking approach, we achieve high temporal resolution for 3D real-time imaging without ECG, breath-holding, or data segmentation, revolutionizing cardiac motion capture.

Keywords: Myocardium, Data Acquisition

Motivation: Cine imaging is important for CMR quantification of left ventricular (LV) function, but conventional breath-held techniques are time consuming. 

Goal(s): This study aims to improve continuous spiral-based cardiac cine acquisition efficiency.

Approach: A CAIPIRINHA-based SMS imaging using spiral acquisition with respiratory correction and cardiac self-gating strategy is proposed.

Results: By optimizing the phase modulation pattern with robust self-gating signal extraction, cine images covering the whole LV are obtained in approximately 30s free breathing without ECG gating. The proposed technique yielded comparable LVEF to the clinical gold-standard. Although image quality was slightly inferior to the clinical technique, SMS-SPARCS produced diagnostically acceptable image quality.

Impact: This study furthers our insight into designing phase modulation and reconstruction techniques for continuous spiral-based multi-slice self-gated acquisition. This technique improves efficiency of cine acquisition and does not require ECG or breath-holding.

Keywords: Myocardium, Myocardium, pulmonary hypertension; mechanical dyssynchrony;

Motivation: The ability of layer-specific intraventricular mechanical dyssynchrony (M-dys) to predict prognosis in pulmonary arterial hypertension (PAH) has not been investigated.

Goal(s): To illustrate the existence and prognostic values of layer-specific intraventricular M-dys and its associations with electronical dyssynchrony in PAH.

Approach: The biventricular volumetric and layer-specific intraventricular M-dys were analyzed by calculating strain and strain rate based on cine cardiac magnetic resonance images.

Results: The layer-specific intraventricular M-dys had varying impacts on biventricular functions in PAH.

Impact: This study was novel in reporting that the layer-specific intraventricular M-dys had various distribution patterns in both ventricles in patients with PAH.

Keywords: Myocardium, Cardiovascular, Ventricular remodeling· Magnetic resonance imaging· ST elevation myocardial infarction· Left atrial reservoir strain rate

Motivation: Understanding reverse left ventricular remodeling (r-LVR) after ST-segment elevation myocardial infarction (STEMI) is important for patients. It is unknown whether left atrium (LA) volume and function can predict r-LVR.

Goal(s): The aim of study was to evaluate the changes in left heart structure and function by performing two cardiac magnetic resonance (CMR) scans and then to explore the value of LA in predicting r-LVR.

Approach: A total of 105 STEMI patients were studied. The predictors of r-LVR were analyzed by logistic regression method.

Results: LV end diastolic volume (LVEDV), total enhanced mass and LA reservoir strain rate were significantly predictors of r-LVR.

Impact: Our study described the natural course of the left heart over time in patients with STEMI, evaluated predictors of left heart for r-LVR, and found that LA reservoir strain rate and LV longitudinal displacement had similar value for predicting r-LVR.

Keywords: Myocardium, Cardiovascular

Motivation: Deep-learning image reconstruction is promising for improving image quality and may enable higher acceleration for cardiac CINE MR.

Goal(s): To investigate deep-learning-based image reconstruction for accelerating cardiac CINE MRI over compressed sensing (CS) reconstructions without affecting quantitative measures of ejection fraction.

Approach: Cardiac CINE MR with CS factors 2-5 were acquired in 15 volunteers and reconstructed with one standard and two AI methods. Ejection fractions were calculated, and a subset of images were graded for image quality.

Results: CS-factors did not materially affect ejection fractions (left-ventricle p=0.969, right-ventricle p=0.998). Blurring (p<0.01) and perceived SNR (p<0.01) were improved by AI reconstruction at high acceleration.

Impact: Deep learning MR reconstruction reduces penalties from high acceleration in cardiac MRI CINE imaging, allowing for shorter breath-holds, shorter exams, non-compromised image quality, and preserved quantitative measurements.

Keywords: Myocardium, Cardiomyopathy

Motivation: CMR, the gold standard for diagnosing myocardial diseases, is known for its ability to assess local myocardial fibrosis through LGE imaging. However, this imaging technique requires a contrast agent, limiting its use in patients with allergies or renal dysfunction.

Goal(s): The purpose of this study is to assess the ability of MVs/MVd as a new indicator to measure the extent of myocardial fibrosis.

Approach: Explore the correlation between MVs/MVd and LGE% in patients with hypertrophic cardiomyopathy.

Results: The results indicate that MVs/MVd may possess the ability to indicate myocardial fibrosis without the need for a contrast agent.

Impact: MVs/MVd, in contrast to traditional methods, directly measures the entire cardiac cycle, offering valuable insights into myocardial properties. Importantly, it can gauge myocardial fibrosis to some extent without requiring a contrast agent, making it clinically significant for diagnosis and treatment.

Keywords: Heart Failure, Cardiovascular

Motivation: To investigate the potential of different CMR parameters as non-invasive, indirect indicators of NT-proBNP levels in HEpEF patients and to assess their utility in enhancing disease prognosis and assessment.

Goal(s): The objective of this study is to explore the relationship between NT-proBNP and left ventricular functional parameters, T1 mapping, ECV, and myocardial strain parameters in CMR.

Approach: A retrospective study was conducted with a cohort of HEpEF patients. Advanced cardiac MRI techniques were utilized to ascertain each CMR parameter.

Results: A notable correlation was discerned between myocardial stress parameters and Native T1 values with serum NT-proBNP levels.

Impact: NT-proBNP is a fundamental biomarker for assessing and predicting alterations in left ventricular function. Myocardial stress parameters and Native T1 showcase potential as non-invasive indicators.Future research must focus on multi-center, prospective studies to validate and expand on these findings.

Keywords: Myocardium, Cardiovascular

Motivation: The two-dimensional (2D) cine balanced steady-state free precession (SSFP) sequence requires multiple breath-holds for cardiac imaging. A three-dimensional (3D) cine Enhanced sensitivity encoding (SENSE) by Static Outer-volume Subtraction (ESSOS) sequence was introduced to reduce the acquisition time.

Goal(s): To explore the diagnostic value of the 3D cine sequence in patients with hypertrophic cardiomyopathy (HCM).

Approach: All patients with HCM were scanned for cine imaging using conventional 2D SSFP and 3D ESSOS sequences. Cardiac structure and function parameters measured by 3D cine and 2D cine were compared.

Results: The 3D cine can rapidly obtain cardiac parameters with good diagnostic accuracy in patients with HCM.

Impact: The 3D ESSOS cine has good diagnostic accuracy for HCM. This sequence can acquire whole-heart images in a single breath hold, greatly improving efficiency and reducing patient discomfort. It should be used to screen people at high risk for HCM.

Keywords: Myocardium, Brain, cardiac function

Motivation: Impaired cardiac function has been associated with cognitive deterioration. However, the correlation of cardiovascular function to cerebral structures remains unclear. 

Goal(s): We studied whether the ventricular function is associated with measures of subcortical volumes in a general patient population. 

Approach: All participants were imaged using a 3T MRI systems. Cardiac 2D SSFP CINE was acquired for cardiac function. Brain structural images were acquired using a 3D MPRAGE.

Results: Among seven subcortical structures examined in 101 healthy adults, only the thalamic volume demonstrated a positive association with left ventricular stroke volume and right ventricular end diastolic volume.

Impact: In healthy adults, the thalamic volume demonstrated a positive association with left and right ventricular stroke volume. 

Keywords: Vascular, Blood vessels

Motivation: The prognosis of advanced pulmonary hypertension (PH) is poor, and incorrect treatment methods may accelerate this process.

Goal(s): To comprehensively investigate the characteristics of PH by employing various imaging sequences, including 4D Flow, cardiac cine, T1/T2mapping. 

Approach:  CMR imaging was performed on different cardiac index (CI) of PH patients and healthy volunteers to calculate various parameters of the heart and pulmonary arteries. Wilcoxon rank test was used to evaluate inter group differences.

Results: A multi-sequence MRI approach effectively detects and characterizes abnormal heart and pulmonary artery features in PH of different CI, offering insights for early diagnosis and clinical management.

Impact: The research has provided initial insights into the cardiac characteristics of high-CI and low-CI PH patients using magnetic resonance imaging (MRI) technology. It offers new data and perspectives to better understand the physiological and pathological changes in these patients.