9 Contrast dose reduction in clinical CMR at 3T MRI: impact on LGE image quality

Introduction Limited data exist on the optimum dose of contrast needed for tissue characterisation using CMR at 3T. We assessed whether reduced contrast dose could provide similar quality of late gadolinium enhanced (LGE) images in standard clinical CMR. Materials and Methods This analysis included patients undergoing clinical CMR scans at Glenfield hospital, Leicester for various indications between November 2022-June 2023. All participants had LGE imaging performed as per clinical practice (either segmented, single-shot or free-breathing motion-corrected) using a 3T scanner (either Siemens Skyra or Vida). Patients underwent CMR scans with a lower dose of contrast (Clariscan, GE HealthCare) at 0.1mmol/kg and were compared with patients receiving the standard dose of 0.15mmol/kg in the previous three months. Scan quality and LGE images were evaluated retrospectively with blinding to dose of contrast given using a grading of non-diagnostic, diagnostic, good or optimum. LGE-to-blood pool ratio was calculated for all participants who had LGE present. Cost-benefit analysis was assessed using standard contrast tariffs and number of vials used per patient. Results 101 participants with standard-dose and 100 participants with low-dose were compared. There was no significant difference in the type of LGE sequence used in the two groups. There was no significant difference in overall scan quality in the standard dose group (non-diagnostic 6%, diagnostic 20%, good 47%, optimum 28%) compared to low dose (non-diagnostic 3%, diagnostic 18%, good 44% and optimum 34%). Likewise, there was no difference in the LGE image quality in the standard dose group (non-diagnostic 3%, diagnostic 17%, good 42%, optimum 39%) compared to low dose (non-diagnostic 2%, diagnostic 7%, good 41%, optimum 50%). Proportion of patients with LGE present was similar between the two groups (Standard 44% vs. Low dose 39%). LGE-to-blood pool ratio was higher in the low-dose compared to the standard-dose group (1.12 [0.71–1.30] vs. 0.76 [0.55–1.05]; P=0.010). Amongst the low-dose group, there was a cost-saving of 29%. Discussion Conclusion The use of standard-dose contrast is not superior to using lower dose contrast when assessing LGE images. Low-dose contrast provides higher LGE-blood pool ratio and is associated with reduced service costs. Acknowledgements