Keywords: Flow, Cardiovascular

Motivation: Mitral valve regurgitation (MVR) is the most common heart valve diseases, but accurate quantification of MVR has been limited due to the dynamic motion of valves. 

Goal(s): We hypothesize that volumetric flow information by 4D flow MRI with the compensation of MV motion could address this challenge.

Approach: MVR was measured using a simulated-in vitro model by comparing with actual flow from pump, ultrasound, and 4D flow MRI with/without a mitral registration algorithm.

Results: PISA method overestimated MVR. 4D flow MRI without algorithm seems to have similar the amount of actual MVR, while it decreased with employing algorithm.
 

Impact: Accurate quantification of regurgitation plays an important role for diagnosing patients with valvular diseases. This study would have a chance to measure accurate MVR quantification and quantify complex intracardiac blood flow using 4D flow MRI.

Keywords: Heart Failure, Cardiovascular

Motivation: Heart failure is a clinical syndrome in which the heart is unable to pump blood efficiently, and Heart Failure with Reduced Ejection Fraction (HFrEF) with the left ventricular ejection fraction (LVEF) < 40% serve as high morbidity and mortality.

Goal(s): The aim of this study is to investigate the hemodynamic environment in left ventricle of different phases.

Approach: 4D flow technology could offer non-invasive method for quantifying the alternatives of intracardiac blood flow components in HFrEF with and without MACE.

Results: Results showed reduced DF-KEiESV, DEF-KEiESV, higher RVo and peak E-wave RVo-KEiEDV were confirmed in MACE+ group when compared with MACE- group.

Impact: The hemodynamic analysis in HFrEF when compared patients with and without MACE illustrated significant alternative of intracardiac blood flow components by using 4D flow technology, which could offer valuable insight for further assessment and treatment planning. 

Keywords: Myocardium, Cardiomyopathy

Motivation: The risk stratification for implantable cardioverter-defibrillators (ICD) placement in high-risk patients with hypertrophic cardiomyopathy (HCM) has challenges.

Goal(s): The aim of this study is to investigate the connection between left atrial and left ventricular strain and sudden cardiac death (SCD) risk stratification by feature-tracking CMR.

Approach: All patients were satisfied by the 2020 AHA/ACC HCM Risk-SCD model with feature-tracking CMR for assessing left atrial and left ventricular strain.

Results: Results demonstrated that both left atrial and left ventricular strain show obvious attenuation in high-risk group than low-risk group. LVGRS+LARS combined model exhibited a superior diagnostic value for identifying high-risk SCD.
 

Impact: The LVGRS+LARS combined model could provide additional predictive value for improving SCD risk stratification in clinical practice, which may provide vital insights into the judicious clinical utilization of ICD to reduce SCD in HCM.

Keywords: Myocardium, Cardiovascular

Motivation: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by progressive myocardial fibro-fatty infiltration accompanied by trabecular disarray. The prognostic value of trabecular disorder assessed by three-dimensional (3D) fractal dimension (FD) measurement is unclear.

Goal(s): To investigate the prognostic value of 3D right ventricular trabecular complexity of ARVC.

Approach: Using cine images, trabecular complexity was measured with 3D fractal analysis to calculate 3D-FD in ARVC patients retrospectively. Cox regression analyses and Kaplan-Meier survival analysis were performed to identify the prognostic value of 3D-FD.

Results: RV 3D-FD was a significant risk predictor for MACE in ARVC and provided incremental prognostic value to conventional predictors.

Impact: Based on the results, we suggested  3D  RV trabecular complexity, derived from non-invasive imaging examination, as a new biomarker for early clinical therapy in medication and ICD implantation in order to moderate the onset of adverse endpoints in ARVC patients.

Keywords: Flow, Data Analysis, 4D flow MRI, Compressed sensing

Motivation: Compressed sensing (CS) acceleration has improved the clinical applicability of 4D flow MRI. However, but no studies have investigated turbulent kinetic energy (TKE) assessment using CS-accelerated 4D flow MRI.

Goal(s): This study aims to validate TKE assessment in CS 4D flow MRI compared to conventional 4D flow MRI.

Approach: The effect of CS acceleration on TKE assessment was evaluated by in vitro coarctation model. In addition, TKE assessment was further validated in healthy subjects and aortic stenosis (AS) patients.

Results: TKE parameters had good agreement in AS patients at the ascending aorta, while healthy subjects had significant differences.

Impact: TKE estimation has been limited due to asymmetric velocity encoding scheme, requiring additional MR scans. This study firstly validates the reliability of TKE using CS 4D flow with reduced scan time in AS patients.

Keywords: Myocardium, Quantitative Imaging, Ex vivo applications, High field MRI, Small animals, Ischemia, Preclinical imaging

Motivation: Conventional CMR techniques have many limitations, such as slowness and inability to provide contrast-agent free 3-D assessments of myocardium in the cardiac diseases.

Goal(s): The aim of this study is to develop a faster, high-resolution 3-D CMR imaging method for quantitative imaging of the myocardium after myocardial infarction (MI).

Approach: Mice hearts were imaged ex vivo 7 days after the factitious MI by using an ultra-short echo time 3-D T_1ρ technique (MB-SWIFT-CS).

Results: The T_1ρ relaxation times were elevated in the infarct area. The findings were validated by 2-D CMR maps and histopathology to confirm ischemia, edema, and fibrosis in the myocardium.

Impact: This study presents a quantitative ultra short echo time 3-D CMR method for ex vivo assessment of myocardium after factitious myocardial infarction in mice. The method allowed rapid comprehensive 3-D myocardial evaluation by utilizing compressed sensing and relaxation time mapping.  

Keywords: Myocardium, Diffusion/other diffusion imaging techniques, acute myocardial infarction, reperfusion injury

Motivation: Cardiac diffusion-weighted(DW)imaging has proven to be an effective approach to explore ischemia reperfusion myocardium damage and inflammation induced by treatment after reperfusion.

Goal(s): The objective of this study was to investigate whether contrast agent (CA) administration significantly affects DWI in the evaluation of reperfused acute myocardial infarction.

Approach: The apparent diffusion coefficient (ADC) values,signal intensity(SI) and contrast-to-noise ratio(CNR) pre- and post-contrast were measured in the intramyocardial hemorrhage (IMH),edema area and remote regions, respectively. 

Results: The ADC values in IMH and edema area were not significantly changed between pre- and post-contrast (P>0.05), while the SI of remote myocardium was inhibited and CNRs were reduced.

Impact: To better assess ischemia reperfusion myocardium damage, DWI is recommended to perform as much as possible before the gadolinium-based contrast agent administration.

Keywords: Vascular, Brain, magnetic resonance imaging; TOF MRA; Anterior choroidal artery AChA; 5.0 T

Motivation:  Improved cerebrovascular disease diagnosis requires enhanced imaging of the anterior choroidal artery (AChA).

Goal(s): To evaluate the effectiveness of a 5.0T ultra-high-field MR scanner for cerebrovascular imaging compared to traditional 3.0T scanners.

Approach: Retrospective analysis using 5.0T MR imaging to assess AChA visualization in patients with cerebrovascular complaints.

Results: The 5.0T scanner significantly outperformed the 3.0T in image quality and detail, providing superior AChA delineation, which is essential for diagnosing related cerebrovascular diseases.

Impact: The 5.0T MR imaging's superior visualization of AChA paves the way for better diagnosis and management of deep brain vascular diseases, potentially influencing treatment outcomes and advancing neurovascular research.  

Keywords: Atherosclerosis, Atherosclerosis

Motivation: Cerebral small vessel disease (CSVD) is a common disease in the elderly with uncertain causes. We wanted to explore whether intracerebral macrovascular disease is related to CSVD.

Goal(s): This study was to explore the relationship between atherosclerotic plaque characteristics and wall changes and white matter hyperintensities (WMH) associated with CSVD.

Approach: As a non-invasive technique, high-resolution vessel wall magnetic resonance imaging can display   vascular image and measure plaque parameters and vascular wall changes. Using the tools, the differences between WMH groups were analyzed.

Results: WMH was associated with unstable plaques. Age, wide distribution and significant enhancement were independent factors affecting WMH.

Impact: Unstable atherosclerotic plaque may cause CSVD, suggesting that clinicians should pay more attention to patients with ischemic stroke. The plaque vulnerability parameter may be a new index to evaluate the degree of WMH.