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

Figure 1. Tomography pipeline. (A)—all sequential steps; (B)—Topogram; red line—carina level for test bolus; green box—heart borders; (C)—adding a marker in the ascending aorta in DynEva Siemens application to form a graphic; (D)—automatic detection time-to-peak in the ascending aorta on the curve during the contrast test bolus; (E)—DS_CorAdSeq (venous phase during contrast enhancement to visualize coronary sinus with tributaries); (F)—3D image of the heart with contrast-enhanced coronary sinus veins.

Figure 2. Example to set a final individual calculated scanning delay for DS-CorAdSeq series: 16 (time-to-peak in the aorta) plus 20 (constant extra value) equals 36 s (final delay in this example).

Figure 3. Visualization of veins during different rhythms. (A)—patient with atrial fibrillation and heart frequency 112 per minute during acquisition with final scan delay 50 s; (B)—patient with sinus rhythm and heart frequency 105 per minute during acquisition with final scan delay 58 s.

Figure 4. Visualization of cases selected for alternative implantation. (A)—blind pocket instead of typical ostial part of coronary sinus. Thin and tortuous ostial part which is connected atypically with right atrium. (B)—thin and short target vein (inappropriate for implantation).

Figure 5. Scatter plot showing the association between heart rate and total venous visualization score. Colored lines represent linear regression fits with 95% confidence intervals for each rhythm group: sinus (sinus rhythm), AF (atrial fibrillation), and RV pace (right ventricular pacing). R2 (coefficient of determination) indicates the proportion of variance in the total score explained by heart rate; the p-value indicates the statistical significance of the linear relationship. No significant linear association was observed in any rhythm group.

Figure 6. Distribution of time-to-peak contrast opacification in the ascending aorta. (A)—the initial data analysis, performed via a histogram with an overlaid density curve, revealed a positive skewness in the distribution. (B)—log (time-to-peak in ascending aorta). The distribution was close to normal.

Figure 7. Scatter plot presenting the Spearman correlation between Hounsfield unit and the time-to-peak contrast opacification in ascending aorta.

Figure 8. Variation in Hounsfield unit (HU) at identical time-to-peak contrast opacification in ascending aorta. (A)—case N1, HU= 88 at the time-to-peak= 22 s; (B)—case N2, HU= 52 at the time-to-peak= 22 s; (C)—case N2 with final view of coronary sinus veins; (D)—case N1 with final view of coronary sinus veins.