Optimal C-arm angulation during transcatheter aortic valve replacement: Accuracy of a rotational C-arm computed tomography based three dimensional heart model

Table 1 Operator variability and model-operator agreement of rotational C-arm computed tomography-based view planning data

n = 57	Average AD (ND)	Average AD (MC)
Operator 1 vs operator 2	7.05°± 3.06°	12.96°
RCT model vs both operators	6.84°± 3.78°	13.82°
RCT model vs operator 1	7.14°± 4.12°	14.37°

To measure the error between two sample C-arm views the angular deviations (AD) are computed and evaluated assuming normal distribution (ND) of the samples and using Monte Carlo (MC) methods. RCT: Rotational C-arm computed tomography.

Table 2 Model-operator agreement for rotational C-arm computed tomography-based diameter measurements

n = 57	Annulus			Sinus			STJ
	Bias	LoA	r	Bias	LoA	r	Bias	LoA	r
Operator vs operator 1	0.32	-3.17-3.81	0.81	-0.45	-3.61-2.71	0.91	-0.59	-3.29-2.10	0.92
RCT model vs operator 1	-0.44	-4.09-3.20	0.79	1.05	-1.64-3.75	0.93	-1.53	-4.21-1.15	0.92
RCT model vs operator 2	-0.76	-3.75-2.23	0.81	1.51	-0.61-3.62	0.96	-0.94	-3.41-1.53	0.93

To assess bias and deviation of measurements the Bland-Altman analysis is used; in addition the Pearson correlation coefficient is computed to evaluate the inter-measurement agreement considering a significance level of P < 0.01. RCT: Rotational C-arm computed tomography; LoA: Limits of agreement (Bland-Altman analysis).