Whole-heart MR Imaging in One Minute: 3D fast cardiac MRI technique employing the non-Cartesian Ultra-short echo time sequence.

Background: Three-dimensional (3D) cardiovascular magnetic resonance angiography (MRA) produces detailed images of the heart and its vascular surroundings. However, the technique is challenged in clinical settings for pediatric patients primarily due to the uncooperative nature of pediatric patients, especially those at young age. This work is to propose and assess a one-minute 3D whole-heart MRI technique for pediatric patients with congenital heart diseases (CHD) based on a non-Cartesian gradient-echo-based ultra-short echo time (UTE) sequence together with the ferumoxytol contrast.

Methods: Both the 3D fast whole-heart MRI sequence and the clinical 3D bSSFP whole-heart sequence were used for acquiring the whole-heart imaging post ferumoxytol contrast. Image quality assessment in reformatted angiograms was performed between the 3D bSSFP and 3D UTE sequence by two readers independently. Statistical analysis was also performed using the paired t-test to assess the statistical significance for image quality. The p-value < 0.05 was considered indicative of a statistically significant difference. Case studies were provided to visually compare images from the proposed technique and the clinical 3D bSSFP sequence.

Results: Thirty-eight studies were performed in 38 consecutive children with a mean age of 10 years [range 5 months - 24 years]. The 3D UTE sequence achieved higher scores in 7 of 10 cardiac structures chosen for comparison. Through statistical analysis, it was determined that the 3D UTE sequence offers superior image quality for all pulmonary veins and maintains comparable quality for the superior vena cava, left atrium, and pulmonary arteries compared to the 3D bSSFP sequence. While for left atrial appendage and ventricular anatomy, the 3D bSSFP sequence was found to yield better image quality compared to the 3D UTE sequence.

Conclusion: The ferumoxytol enhanced 3D UTE sequence enables whole-heart imaging in less than one minute with clinical-acceptable image quality and hence can be used as a supplemental tool for the 3D bSSFP sequence in clinical practice.