Jiaxin Shao

Myocardial T1 mapping at 3.0 tesla using an inversion recovery spoiled gradient echo readout and bloch equation simulation with slice profile correction (BLESSPC) T1 estimation algorithm

To develop an accurate and precise myocardial T1 mapping technique using an inversion recovery spoiled gradient echo readout at 3.0 Tesla (T).

Instantaneous signal loss simulation (InSiL): An improved algorithm for myocardial T1 mapping using the MOLLI sequence

To propose a T1 mapping algorithm for the modified Look‐Locker inversion‐recovery (MOLLI) sequence that can improve T1 estimation accuracy.

Cardiac MRI: a Translational Imaging Tool for Characterizing Anthracycline-Induced Myocardial Remodeling

Cardiovascular side effects of cancer therapeutics are the leading causes of morbidity and mortality in cancer survivors. Anthracyclines (AC) serve as the backbone of many anti-cancer treatment strategies, but dose-dependent myocardial injury limits their use. Cumulative AC exposure can disrupt the dynamic equilibrium of the myocardial microarchitecture while repeated injury and repair leads to myocyte loss, interstitial myocardial fibrosis, and impaired contractility. Although children are assumed to have greater myocardial plasticity, AC exposure at a younger age portends worse prognosis. In older patients, there is lower overall survival once they develop cardiovascular disease. Because aberrations in the myocardial architecture predispose the heart to a decline in function, early detection with sensitive imaging tools is crucial and the implications for resource utilization are substantial. As a comprehensive imaging modality, cardiac magnetic resonance (CMR) imaging is able to go beyond quantification of ejection fraction and myocardial deformation to characterize adaptive microstructural and microvascular changes that are important to myocardial tissue health. Herein, we describe CMR as an established translational imaging tool that can be used clinically to characterize AC-associated myocardial remodeling.

Myocardial T1 mapping for patients with implanted cardiac devices using wideband inversion recovery spoiled gradient echo readout

To develop and validate a technique for myocardial T1 mapping in patients with implantable cardioverter defibrillators (ICDs).

Accuracy, precision, and reproducibility of myocardial T1 mapping: A comparison of four T1 estimation algorithms for modified look‐locker inversion recovery (MOLLI)

To compare the accuracy and precision of four different T1 estimation algorithms for modified Look‐Locker inversion recovery (MOLLI).

Phase contrast MRI with flow compensation view sharing.

To develop and evaluate a technique for accelerating phase contrast MRI (PC‐MRI) acquisitions without significant compromise in flow quantification accuracy.

Phase-contrast MRI with hybrid one and two-sided flow-encoding and velocity spectrum separation.

To develop and evaluate a phase‐contrast MRI (PC‐MRI) technique with hybrid one and two‐sided flow‐encoding and velocity spectrum separation (HOTSPA) for accelerated blood flow and velocity measurement.

Hybrid One- and Two-sided Flow-Encodings Only (HOTFEO) to accelerate 4D flow MRI

Background 4D flow phase-contrast MRI (PC-MRI) has been extensively used for visualization and quantification of blood flow and velocity. It typically acquires one flow-compensated (FC) and three-directional (3D) flow-encoded (FE) echoes (FC/3FE) to update one cardiac phase, which often limits the achievable temporal resolution and temporal footprint for each cardiac phase. In this work, we propose a Hybrid Oneand Two-sided Flow-Encodes Only (HOTFEO) acquisition strategy (as shown in Figure 1) that incorporates with a velocity direction constraint (assuming the velocity direction, not magnitude, changes very little between two cardiac phases) to accurately calculate without acquiring FC data to achieve 4/ 3-fold acceleration. Retrospective and prospective in vivo studies were performed to validate the measurement accuracy of total volumetric flow and maximal total peak velocity.

Accelerated phase contrast MRI using hybrid one- and two-sided flow encodings only (HOTFEO)

The aim of this work was to develop and evaluate a fast phase contrast magnetic resonance imaging (PC‐MRI) technique with hybrid one‐ and two‐sided flow encodings only (HOTFEO) for accurate blood flow and velocity measurements of three‐directional velocity encoding PC‐MRI. Four‐dimensional (4D) PC‐MRI acquires flow‐compensated (FC) and three‐directional flow‐encoded (FE) echoes in an interleaved fashion. We hypothesize that the blood flow velocity direction (not magnitude) has minimal change between two consecutive cardiac phases. This assumption provides a velocity direction constraint that can achieve 4/3‐fold acceleration using three‐directional FE data to calculate FC data instead of acquiring them. The HOTFEO acquisition pattern can address the ill‐conditioned constraint and improve the calculation accuracy. HOTFEO was evaluated in healthy volunteers and compared with conventional two‐dimensional (2D) and 4D flow imaging techniques with FC and three‐directional FE acquisitions (FC/3FE). Compared with FC/3FE, Bland–Altman tests showed that the 4/3‐fold accelerated HOTFEO technique resulted in relatively small bias error for total volumetric flow (0.89% for prospective 2D data, –1.19% for retrospective 4D data and –3.40% for prospective 4D data) and maximum peak velocity (0.50% for prospective 2D data, –0.17% for retrospective 4D data and –2.00% for prospective 4D data) measurements in common carotid arteries. HOTFEO can accelerate three‐directional velocity encoding PC‐MRI whilst maintaining the measurement accuracy of the total volumetric flow and maximum peak velocity.

Improved myocardial T1 mapping for patients with implanted cardiac devices

Background Myocardial T1 mapping holds promise for non-invasive evaluation of diffuse fibrosis. Nevertheless, the widely used cardiac T1 mapping techniques, including MOLLI and SASHA, are generally not applicable to patients with implanted cardiac devices, such as implantable cardioverter defibrillators (ICDs) and pacemakers, due to large off-resonance induced by the device and the associated banding artifacts when using bSSFP readouts. We sought to develop and validate an improved technique for accurate myocardial T1 mapping in patients with implanted cardiac devices.