Aortic velocity measurements derived from phase-contrast MRI are influenced by a cardiac implantable electronic device in both adult and pediatric human subjects

Purpose: Overall there is a lack of evidence on the accuracy and precision of phase-contrast (PC) MRI in patients with cardiac implantable electronic devices (CIEDs). The purpose of this study is to determine whether aortic velocity measurements are influenced by a CIED.

Methods: We scanned 21 adult patients and 8 pediatric volunteers using clinical standard PC and real-time PC (rt-PC) sequences with and without a CIED generator taped on human subjects (below the left clavicle for adults and children; also on the abdomen for children) to mimic image artifacts. Peak and mean velocities above the aortic valve were calculated.

Results: The Bland-Altman analyses on peak velocity measurements in pediatric subjects showed that both the accuracy and precision worsen as the distance between the CIED and aortic valve decreases (i.e., from abdomen to below the left clavicle). Specifically, both the bias and the coefficient of variation (CV) for both clinical PC and rt-PC increased from the abdominal position (clinical: bias = -1.1%, CV = 4.3%; rt-PC: bias = -0.3%, CV = 3.4%) to the clavicle position (clinical: bias = -4.0%, CV = 8.1%; rt-PC: bias = 8.2%, CV = 7.3%). A similar trend was observed for mean velocity. The mean difference in peak and mean velocity measurements between rt-PC with CIED (either position) and clinical standard PC with no CIED was within 7.5%. In adult patients, the mean difference between rt-PC with CIED and clinical standard PC with CIED in peak velocity was 6.9%, and the CV was 7.9%.

Conclusion: This study demonstrates that aortic velocity measurements are influenced by CIED in both adult and pediatric subjects.