Assessment of left ventricular function and mass in dual-source computed tomography coronary angiography: influence of beta-blockers on left ventricular function: comparison to magnetic resonance imaging.

Purpose: To quantify left ventricular (LV) function and mass (LVM) derived from dual-source computed tomography (DSCT) and the influence of beta-blocker administration compared to cardiac magnetic resonance imaging (CMR).

Methods: Thirty-two patients undergoing cardiac DSCT and CMR were included, where of fifteen received metoprolol intravenously before DSCT. LV parameters were calculated by the disc-summation method (DSM) and by a segmented region-growing algorithm (RGA). All data sets were analyzed by two blinded observers. Interobserver agreement was tested by the intraclass correlation coefficient. RESULTS.: 1. Using DSM LV parameters were not statistically different between DSCT and CMR in all patients (DSCT vs. CMR: EF 63+/-8% vs. 64+/-8%, p=0.47; EDV 136+/-36 ml vs. 138+/-35 ml, p=0.66; ESV 52+/-21 ml vs. 52+/-22 ml, p=0.61; SV 83+/-22 ml vs. 87+/-19 ml, p=0.22; CO 5.4+/-0.9l/min vs. 5.7+/-1.2l/min, p=0.09, LVM 132+/-33 g vs. 132+/-33 g, p=0.99). 2. In a subgroup of 15 patients beta-blockade prior to DSCT resulted in a lower ejection fraction (EF), stroke volume (SV), cardiac output (CO) and increase in end systolic volume (ESV) in DSCT (EF 59+/-8% vs. 62+/-9%; SV 73+/-17 ml vs. 81+/-15 ml; CO 5.7+/-1.2l/min vs. 5.0+/-0.8 l/min; ESV 52+/-27 ml vs. 57+/-24 ml, all p<0.05). 3. Analyzing the RGA parameters LV volumes were not significantly different compared to DSM, whereas LVM was higher using RGA (177+/-31 g vs. 132+/-33 g, p<0.05). Interobserver agreement was excellent comparing DSM values with best agreement between RGA calculations.

Conclusion: Left ventricular volumes and mass can reliably be assessed by DSCT compared to CMR. However, beta-blocker administration leads to statistically significant reduced EF, SV and CO, whereas ESV significantly increases. DSCT RGA reliably analyzes LV function, whereas LVM is overestimated compared to DSM.