At the University of California San Diego (UCSD), we have developed a premier advanced clinical cardiovascular imaging program, which is a critical component of our Adult Congenital Heart Association (ACHA)-accredited adult congenital heart program. Central to these programs is 4D Flow MRI, which enables hemodynamic assessment of patients with repaired and unrepaired congenital heart disease. Adults with congenital heart disease require routine MRI for surveillance and management of complications of disease and repairs, and 4D Flow allows us to reliably perform these exams efficiently and accurately. Multiple works by our group, and confirmed by others, have highlighted the value of 4D Flow MRI for evaluating this patient population, and for vascular imaging applications beyond the heart.
Gadopiclenol is a recently FDA-approved intravenous, extracellular gadolinium contrast agent indicated for use in MRI. Though it has been shown to be effective in detection of central nervous system (CNS) lesions and of lesions outside the CNS, its performance in cardiovascular imaging is unknown, particularly in cardiac MRI performed for evaluation of adult congenital heart disease. We therefore seek to evaluate whether use of gadopiclenol results in superior image quality compared to, and therefore may be used in place of, gadobenate dimeglumine, our current standard of care in 4D Flow MRI and MR Angiography (MRA).
In our current clinical practice, like many others, gadobenate dimeglumine at 0.3 mL/kg (0.15 mmol/kg) is our standard of care for vascular enhancement and cardiac MRI, favored due to its long blood pool residence time, which parallels the longer acquisition time for 4D Flow MRI (\~10 minutes), and its strong T1 shortening properties. Gadopiclenol, with its stronger T1 shortening properties and similar pharmacokinetics, may achieve similar effects but as a macrocyclic agent is a more stable gadolinium agent, and theoretically may have a better retention profile than older linear agents due to its lower approved dose. We therefore seek to determine whether gadopiclenol may be used in place of gadobenate dimeglumine for contrast-enhanced 4D Flow MRI and MRA. Since the optimal dose of gadopiclenol for this purpose is unknown, we will assess the relative performance of gadopiclenol across a dose range.
Standard dosing for gadopiclenol for CNS and abdominal imaging in adult and pediatric patients is 0.05 mmol/kg actual body weight (equivalent to 0.1 mL/kg). However, its safety has been evaluated at doses ranging from 0.025 mmol/kg to 0.3 mmol/kg. We therefore plan to assess the signal to noise ratio and image quality of patients undergoing cardiac MRI using gadopiclenol at three doses (0.075 mmol/kg, 0.10 mmol/kg, 0.15 mmol/kg) against our standard of care (gadobenate dimeglumine at 0.3 mL/kg (0.15 mmol/kg)). We hypothesize that gadopiclenol at each dose will be non-inferior to gadobenate dimeglumine, achieving similar qualitative image quality, similar SNR, and similar standard deviation amongst flow measurements with 4D Flow MRI. There is a strong possibility that gadopiclenol at an equimolar gadolinium dose to gadobenate dimeglumine will provide superior qualitative image quality and superior SNR in contrast-enhanced MRA and reduce standard deviation amongst flow measurements with 4D Flow MRI.