Contrast Agents
Patrick Doeblin, MD
Cardiologist
German Heart Center Charité, Germany
Patrick Doeblin, MD
Cardiologist
German Heart Center Charité, Germany
Fridolin Steinbeis, MD
Physician
Charité – Universitätsmedizin Berlin, Germany
Martin Witzenrath, MD
Physician
Charité – Universitätsmedizin Berlin, Germany
Dawid Hashemi, MD
Cardiologist
German Heart Center Berlin, Germany
Wensu Chen, MD, PhD
Physician
Affiliated Hospital of Xuzhou Medical University, China (People's Republic)
Karl Jakob Weiss, MD
Physician
German Heart Center of the Charité
Berlin, Berlin, Germany
Burkert Pieske, MD
Head of Departement
Charité – Universitätsmedizin Berlin, Berlin, Germany
Sebastian Kelle, MD, FSCMR
Cardiologist
German Heart Center Berlin
Berlin, Berlin, Germany
Cardiac magnetic resonance (CMR) imaging with gadolinium-based contrast agents offers unique non-invasive insights into cardiac tissue composition. Myocardial extracellular volume (ECV) has evolved as an objective and robust parameter with broad diagnostic and prognostic implications. For the gadolinium compound gadobutrol, the recommended dose for cardiac imaging, including ECV measurements, is 0.1 mmol/kg (single dose). This dose was optimized for late enhancement imaging, a measure of focal fibrosis. Whether a lower dose is sufficient for ECV measurements is unknown. We aim to evaluate the accuracy of ECV measurements using a half dose of 0.05 mmol/kg gadobutrol compared to the standard single dose of 0.1 mmol/kg.
Methods:
A retrospective analysis of 18 examinations with available T1 mapping before and after both 0,05 and 0.1 mmol/kg gadobutrol (Gadovist®, Bayer Healthcare, Leverkusen, Germany) was performed. All patients were examined with a clinical 3 Tesla MRI scanner (Ingenia, Philips Healthcare, Best, The Netherlands) equipped with a body receiver coil. T1-mapping was performed using a modified Look-Locker (MOLLI) 5s(3s)3s – scheme.
T1 measurements were performed in the midventricular septum and ECV values calculated from pre- and post-contrast T1 relaxation times.
Results:
Basic demographic parameters and CMR results are given in Table 1. A Bland-Altman plot of ECV values 10 minutes after the first dose of 0.05 mmol/kg and 15 minutes after the second dose of 0.05 mmol/kg (for a total dose of 0.1 mmol/kg) is depicted in Figure 1.
ECV values after 0.05 and 0.1 mmol/kg gadobutrol were correlated (r = .835, P < .001). ECV values after 0.05 mmol/kg gadobutrol had a bias of +1.1% (95%-CI [0.1;2.0], P = .031) compared to 0.1 mmol/kg gadobutrol, with limits of agreement from -2.8 to 4.9 %. There was no correlation between bias and hematocrit (r = -.051, P = .841)
Conclusion:
ECV measurements with a reduced dose of 0.05 mmol/kg gadobutrol are an acceptable alternative in situations where the contrast dose must be minimized, late enhancement imaging is not necessary and clinical relevant alterations in ECV are expected, as in cardiac amyloidosis.