Personalized Test Bolus MSCT Protocol for Optimal Coronary Sinus Venous Visualization in Candidates for Cardiac...

Background/Objectives: A thorough understanding of the anatomy of the coronary sinus (CS) and its tributaries provides valuable information for selecting the optimal left ventricular lead and may even prompt reconsideration of the endovascular implantation strategy when planning cardiac resynchronization therapy (CRT). Currently, there is no personalized multislice computer tomography (MSCT) protocol for CS veins visualization that is suitable for all diverse candidates. Methods: a single-center prospective study included 74 various adult patients with recommendation class I and IIA for CRT. Prior to implantation, all participants underwent contrast MSCT to evaluate the CS veins. The first aspect of MSCT involved the administration of a test bolus to enable the automated calculation of the time-to-peak contrast opacification within the ascending aorta. The second aspect consisted of adding a fixed extra value of 20 s. The resulting sum was then used as the final delay to scan CS veins. The final cardiac acquisition was performed with prospective gating and manual phase in the range of 200-400 ms. The contrast media involved a standard iodine concentration of 300 mg I/mL, an injection rate not exceeding 4.5 mL/s, and a total contrast dose of up to 115 mL. Results: in all patients presented, all first-order CS branches were detected. The analysis found no statistically significant effect of heart rate and heart rhythm on the quality of venous visualization. The coefficient of determination (r_s²) revealed that only 28.9% of the rank variability in time-to-peak contrast opacification can be explained by Hounsfield unit. This underscores that only the test-bolus protocol with definitively calculated time delay can ensure a personalized optimal enhancement of CS veins. Conclusions: a personalized, detailed test bolus MSCT protocol for coronary sinus veins visualization is presented. Multi-vendor, multi-center studies are warranted to confirm the generalizability and external validity of the proposed MSCT protocol.