Comprehensive motion‐compensated highly accelerated 4D flow MRI with ferumoxytol enhancement for pediatric congenital heart disease

Abstract

Purpose To develop and evaluate motion-compensation and compressed-sensing techniques in 4D flow MRI for anatomical assessment in a comprehensive ferumoxytol-enhanced congenital heart disease (CHD) exam. Materials and Methods A Cartesian 4D flow sequence was developed to enable intrinsic navigation and two sampling schemes: VDPoisson and VDRad. Four compressed-sensing methods were developed: A) VDPoisson scan reconstructed using spatial wavelets, B) added temporal total variation to A, C) VDRad scan using the same reconstruction as in B, and D) added motion compensation to C. With IRB approval and HIPAA compliance, 23 consecutive patients (8 females, mean 6.3 years) referred for ferumoxytol-enhanced CHD 3T MRI were recruited. Images were acquired and reconstructed using methods A–D. Two cardiovascular radiologists independently scored the images on a 5-point scale. These readers performed a paired wall motion and functional assessment between method D and 2D bSSFP CINE for 16 cases. Results Method D had higher diagnostic image quality for most anatomical features (mean 3.8–4.8) compared to A (2.0–3.6), B (2.2–3.7), and C (2.9–3.9) with P < 0.05 with good inter-observer agreement (κ ≥ 0.49). Method D had similar or better assessment of myocardial borders and cardiac motion compared to 2D bSSFP (P < 0.05, κ ≥ 0.77). All methods had good internal agreement in comparing aortic with pulmonic flow (BA mean < 0.02%, r > 0.85) and compared to method A (BA mean < 0.13%, r > 0.84) with P < 0.01. Conclusion Flow, functional, and anatomical assessment in CHD with ferumoxytol-enhanced 4D flow is feasible and can be significantly improved using motion compensation and compressed sensing.

Assessment of the precision and reproducibility of ventricular volume, function, and mass measurements with ferumoxytol‐enhanced 4D flow MRI

“…However, with the implementation of under-sampling methods including parallel imaging and compressed sensing, near-isotropic images can now be acquired in a scan time practical for clinical practice (9). Recent advances in motion-compensation and compressed sensing may further improve the temporal resolution of 4D flow imaging (31). Under-sampling methods and nonlinear reconstruction approaches have also been applied to real-time, free-breathing and single-breath hold cine acquisitions with promising results (32–34).…”

Current and potential imaging applications of ferumoxytol for magnetic resonance imaging

“…On the other hand, ferumoxytol supports the acquisition of 4-dimensional images of the beating heart with Four-Dimensional, Multiphase, Steady-State Imaging with Contrast Enhancement (MUSIC) (Figure 16) (99). Similarly, comprehensive motion-compensated highly accelerated 4D flow MRI with ferumoxytol enhances the quality of 4-dimensional flow information with reduced respiratory motion artifacts in children with congenital heart disease (100, 101). …”

“…A compelling advantage of ferumoxytol is that it enables volumetric temporally-resolved high resolution imaging without breath holding (99). Further, a free-breathing volumetric comprehensive MRI yielding flow, function, and anatomic assessment in less than 10 min has been achieved (100). Additionally, ventricular mass may be quantified with this same technique (101).…”

Comprehensive Multi-Dimensional MRI for the Simultaneous Assessment of Cardiopulmonary Anatomy and Physiology

“…Here, we focused on resolving pulsatile blood flow dynamics; thus, the acquisition scheme was optimized for cardiac-triggered imaging. This view-ordering design is described in detail in refs 25, 39 and is described briefly here. The VDRad scheme was first used to generate N c  ×  N e sampling masks where N c is the desired number of cardiac phases and N e is the number of different velocity-encoding echoes.…”