Improved coronary magnetic resonance angiography using gadobenate dimeglumine in pediatric congenital heart disease

Background: CMRA in pediatrics remains challenging due to the smaller vessel size, high heart rates (HR), potential image degradation caused by limited patient cooperation and long acquisition times. High-relaxivity contrast agents have been shown to improve coronary imaging in adults, but limited data is available in children. We sought to investigate whether gadobenate dimeglumine (Gd-BOPTA) together with self-navigated inversionprepared coronary magnetic resonance angiography (CMRA) sequence design improves coronary image quality in pediatric patients. Methods: Forty consecutive patients (mean age 6 +/- 2.8 years; 73% males) were prospectively recruited for a 1.5-T MRI study under general anesthesia. Two electrocardiographic-triggered free breathing steady-state free precession (SSFP) angiography sequences (A and B) with isotropic spatial resolution (1.3 mm(3)) were acquired using a recently developed image-based self-navigation technique. Sequence A was acquired prior to contrast administration using T2 magnetization preparation (T2prep). Sequence B was acquired 5-8 min after a bolus of Gd-BOPTA with the T2prep replaced by an inversion recovery (IR) pulse to null the signal from the myocardium. Scan time, signal-to noise and contrast-to-noise ratios (SNR and CNR), vessel wall sharpness (VWS) and qualitative visual score for each sequence were compared. Results: Scan time was similar for both sequences (5.3 +/- 1.8 vs 5.2 +/- 1.5 min, p = .532) and average heart rate (78 +/- 14.7 vs 78 +/- 14.5 bpm, p = .443) remained constant throughout both acquisitions. Sequence B resulted in higher SNR (12.6 +/- 4.4 vs 31.1 +/- 7.4, p < .001) and CNR (9.0 +/- 1.8 vs 13.5 +/- 3.7, p < .001) and provided improved coronary visualization in all coronary territories (VWS A = 0.53 +/- 0.07 vs B = 0.56 +/- 0.07, p = .001; and visual scoring A = 3.8 +/- 0.59 vs B = 4.1 +/- 0.53, p < .001). The number of non-diagnostic coronary segments was lower for sequence B [A = 42 (13.1%) segments vs B = 33 (10.3%) segments; p = .002], and contrary to the pre-contrast sequence, never involved a proximal segment. These results were independent of the patients' age, body surface area and HR. Conclusions: The use of Gd-BOPTA with a 3D IR SSFP CMRA sequence results in improved coronary visualization in small infants and young children with high HR within a clinically acceptable scan time.