High-field MR imaging in pediatric congenital heart disease: Initial results

BackgroundComprehensive assessment of pediatric congenital heart disease (CHD) at any field strength mandates evaluation of both vascular and dynamic cardiac anatomy for which diagnostic quality contrast-enhanced magnetic resonance angiography (CEMRA) and cardiac cine are crucial.ObjectiveTo determine whether high-resolution (HR) CEMRA and steady-state free precession (SSFP) cine can be performed reliably at 3.0 T in children with CHD and to compare the image quality to similar techniques performed at 1.5 T.Materials and methodsTwenty-eight patients with a median age of 5 months and average weight 9.0 ± 7.8 kg with suspected or known CHD were evaluated at 3.0 T. SSFP cine (n = 86 series) and HR-CEMRA (n = 414 named vascular segments) were performed and images were scored for image quality and artifacts. The findings were compared to those of 28 patients with CHD of similar weight who were evaluated at 1.5 T.ResultsOverall image quality on HR-CEMRA was rated as excellent or good in 96% (397/414) of vascular segments at 3.0 T (k = 0.49) and in 94% (349/371) of vascular segments at 1.5 T (k = 0.36). Overall image quality of SSFP was rated excellent or good in 91% (78/86) of cine series at 3.0 T (k = 0.55) and in 81% (87/108) at 1.5 T (k = 0.47). Off-resonance artifact was common at both field strengths, varied over the cardiac cycle and was more prevalent at 3.0 T. At 3.0 T, off-resonance dark band artifact on SSFP cine was absent in 3% (3/86), mild in 69% (59/86), moderate in 27% (23/86) and severe in 1% (1/86) of images; at 1.5 T, dark band artifact was absent in 16% (17/108), mild in 69% (75/108), moderate in 12% (13/108) and severe in 3% (3/108) of cine images. The signal-to-noise ratio and contrast-to-noise ratio of both SSFP cine and HR-CEMRA images were significantly higher at 3.0 T than at 1.5 T (P < 0.001).ConclusionSignal-to-noise ratio and contrast-to-noise ratio of high-resolution contrast-enhanced magnetic resonance angiography and SSFP cine were higher at 3.0 T than at 1.5 T. Artifacts on SSFP cine were cardiac phase specific and more prevalent at 3.0 T such that frequency-tuning was required in one-third of exams. In neonates, high spatial resolution CEMRA was highly reliable in defining extracardiac vascular anatomy

Four-dimensional, multiphase, steady-state imaging with contrast enhancement (MUSIC) in the heart: a feasibility study in children

International audiencePURPOSE: To develop a technique for high resolution, four-dimensional (4D), multiphase, steady-state imaging with contrast enhancement (MUSIC) in children with complex congenital heart disease. METHODS: Eight pediatric patients underwent cardiovascular MRI with controlled mechanical ventilation after ferumoxytol administration. Breath-held contrast-enhanced MRA (CE-MRA) was performed during the first-pass and delayed phases of ferumoxytol, followed by a respiratory gated, 4D MUSIC acquisition during the steady state distribution phase of ferumoxytol. The subjective image quality and image sharpness were evaluated. Assessment of ventricular volumes based on 4D MUSIC was compared with those based on multislice 2D cardiac cine MRI. RESULTS: The 4D MUSIC technique provided cardiac-phase-resolved (65-95 ms temporal resolution) and higher spatial resolution (0.6-0.9 mm isotropic) images than previously achievable using first-pass CE-MRA or 2D cardiac cine. When compared with Ferumoxytol-based first-pass CE-MRA, the 4D MUSIC provided sharper images and better definition of the coronary arteries, aortic root, myocardium, and pulmonary trunk (P \textless 0.05 for all). The ventricular volume measurements were in good agreement between 4D MUSIC and 2D cine (concordance correlation coefficient \textgreater0.95). CONCLUSION: The 4D MUSIC technique may represent a new paradigm in MR evaluation of cardiovascular anatomy and function in children with complex congenital heart disease

MRI with ferumoxytol: A single center experience of safety across the age spectrum

PurposeTo summarize our single-center safety experience with the off-label use of ferumoxytol for magnetic resonance imaging (MRI) and to compare the effects of ferumoxytol on monitored physiologic indices in patients under anesthesia with those of gadofosveset trisodium.Materials and methodsConsecutive patients who underwent ferumoxytol-enhanced (FE) MRI exams were included. Adverse events (AEs) were classified according to the Common Terminology Criteria for Adverse Events v4.0. In a subgroup of patients examined under general anesthesia, recording of blood pressure, heart rate, oxygen saturation, and end-tidal CO2 was performed. A comparable group of 23 patients who underwent gadofosveset-enhanced (GE) MRI under anesthesia with similar monitoring was also analyzed.ResultsIn all, 217 unique patients, ages 3 days to 94 years, underwent FE-MRI. No ferumoxytol-related severe, life-threatening, or fatal AEs occurred acutely or at follow-up. Two patients developed ferumoxytol-related nausea. Between-group (FE- vs. GE-MRI) comparisons showed no statistical difference in heart rate (P = 0.69, 95% confidence interval [CI] 96-113 bpm), mean arterial blood pressure (MAP) (P = 0.74, 95% CI 44-52 mmHg), oxygen saturation (P = 0.76, 95% CI 94-98%), and end-tidal CO2 (P = 0.73, 95% CI 31-37 mmHg). No significant change in MAP (P = 0.12, 95% CI 50-58 mmHg) or heart rate (P = 0.25, 95% CI 91-105 bpm) was noted between slow infusion of ferumoxytol (n = 113) vs. bolus injection (n = 104).ConclusionIn our single-center experience, no serious AEs occurred with the diagnostic use of ferumoxytol across a wide spectrum of age, renal function, and indications. Because of the limited sample size, firm conclusions cannot be drawn about the generalizability of our results. Thus, vigilance and monitoring are recommended to mitigate potential rare adverse reactions.Level of evidence2 J. Magn. Reson. Imaging 2017;45:804-812

4D MUSIC CMR: value-based imaging of neonates and infants with congenital heart disease

Abstract Background 4D Multiphase Steady State Imaging with Contrast (MUSIC) acquires high-resolution volumetric images of the beating heart during uninterrupted ventilation. We aim to evaluate the diagnostic performance and clinical impact of 4D MUSIC in a cohort of neonates and infants with congenital heart disease (CHD). Methods Forty consecutive neonates and infants with CHD (age range 2 days to 2 years, weight 1 to 13 kg) underwent 3.0 T CMR with ferumoxytol enhancement (FE) at a single institution. Independently, two readers graded the diagnostic image quality of intra-cardiac structures and related vascular segments on FE-MUSIC and breath held FE-CMRA images using a four-point scale. Correlation of the CMR findings with surgery and other imaging modalities was performed in all patients. Clinical impact was evaluated in consensus with referring surgeons and cardiologists. One point was given for each of five key outcome measures: 1) change in overall management, 2) change in surgical approach, 3) reduction in the need for diagnostic catheterization, 4) improved assessment of risk-to-benefit for planned intervention and discussion with parents, 5) accurate pre-procedural roadmap. Results All FE-CMR studies were completed successfully, safely and without adverse events. On a four-point scale, the average FE-MUSIC image quality scores were >3.5 for intra-cardiac structures and >3.0 for coronary arteries. Intra-cardiac morphology and vascular anatomy were well visualized with good interobserver agreement (r = 0.46). Correspondence between the findings on MUSIC, surgery, correlative imaging and autopsy was excellent. The average clinical impact score was 4.2 ± 0.9. In five patients with discordant findings on echo/MUSIC (n = 5) and catheter angiography/MUSIC (n = 1), findings on FE-MUSIC were shown to be accurate at autopsy (n = 1) and surgery (n = 4). The decision to undertake biventricular vs univentricular repair was amended in 2 patients based on FE-MUSIC findings. Plans for surgical approaches which would have involved circulatory arrest were amended in two of 28 surgical cases. In all 28 cases requiring procedural intervention, FE-MUSIC provided accurate dynamic 3D roadmaps and more confident risk-to-benefit assessments for proposed interventions. Conclusions FE-MUSIC CMR has high clinical impact by providing accurate, high quality, simple and safe dynamic 3D imaging of cardiac and vascular anatomy in neonates and infants with CHD. The findings influenced patient management in a positive manner