Objectives: We aimed to establish the feasibility of acquiring 3.0-T cardiac MRIs without sedation, anesthesia, or breath-holding for preterm infants and to obtain preliminary quantitative data on left ventricular function in this population.
Methods: Twelve preterm infants underwent 3.0-T cardiac MRI without sedation or breath-holding. The median gestational age was 29 weeks (range: 26-33 weeks), the median birth weight was 1240 g (range: 808-2200 g), and the median postconceptional age at the time of cardiac MRI was 33 weeks (range: 31-40 weeks). Anatomic images were acquired with T2-weighted spin-echo sequences, and ventricular function was assessed with balanced steady-state free precession cine sequences. We assessed left ventricular function by using the area-length ejection fraction method on horizontal long-axis images and the volumetric Sergeant's discs method of analysis on short-axis images.
Results: Imaging was successful for 10 of 12 infants. For those 10, the area-length ejection fraction method in the horizontal long-axis plane estimated median stroke volume at 2.9 mL, cardiac output at 0.4 L/minute, end-diastolic volume at 3.8 mL, end-systolic volume at 0.3 mL, and ejection fraction at 74.6%. Short-axis volumetric estimations were made for 4 infants. With this approach, the median stroke volume was 2.4 mL, cardiac output 0.35 L/minute, end-diastolic volume 4.3 mL, end-systolic volume 2.1 mL, and ejection fraction 56%.
Conclusions: Three-tesla cardiac MRI is feasible for preterm infants without sedation, anesthesia, or breath-holding and has the potential to provide a wide range of precise quantitative data that may be of great value for the investigation of cardiac function in preterm infants.