Measuring Biventricular Function and Left Atrial Volume in a Single 5D Whole-Heart CMR Scan at 0.55T.

Abstract

Background: CMR has not seen widespread adoption beyond large urban academic centers. The reasons for this limited uptake include the cost, time-intensive nature and special expertise of CMR. Self-navigated 5D, x-y-z-cardiac-respiratory, free-funning whole-heart CMR using self-navigation (5D CMR) implemented on a low-field clinical scanner may help bridge this gap for bi-ventricular function assessment and left atrium volume index measurement.

Methods: Whole-heart 3D radial phyllotaxis bSSFP data were collected in 10 healthy adult subjects. Self-navigation was used to extract respiratory and cardiac motion signals and to generate motion-resolved 5D CMR datasets. The right- and left-ventricular ejection fraction (RVEF and LVEF), left atrial volume index (LAVI), contrast ratio, sharpness, perceived image quality, and total scan durations were ascertained and compared to those obtained with the reference 2D cine images.

Results: 5D CMR allowed for time-efficient and concordant measurements when compared to the 2D reference method. The 5D CMR images resulted in lower CR on 5D CMR images (3.3 ± 2.9) than on 2D cines (4.7 ± 1.2), and similarly lower perceived image quality (1.8 ± 0.8 for 5D CMR and 3.6 ± 0.9 for the 2D cines). However, the LVEF measurements were similar with no statistically significant differences (Mean: 58 ± 5% for 5D CMR and 59 ± 5% for 2D cine, p = 0.49) and the LoA were low (-2.81% to 3.81%). For the RVEF, the measurements were also in good agreement when RVEF was measured on the axial views (60 ± 3% for 5D CMR and 60 ± 4% for 2D cine, p = 0.85) and the LoA were also low (-2.87% to 3.07%).

Conclusion: 5D CMR without the need for ECG, breath-holding, navigators, or complex scan planning enables a highly simplified and time-efficient assessment of bi-ventricular cardiac function on a 0.55T clinical system in 7:50min.