论文信息 - Left ventricular 4D imaging with low radiation dose through optimised interphase registration of rotational angiography images

Left ventricular 4D imaging with low radiation dose through optimised interphase registration of rotational angiography images

Cardiologia CROATICA Objectives: VT ablations could benefit from dynamic 3D (i.e. 4D) visualisation of the left ventricle (LV) as roadmap for anatomy-guided procedures, e.g. by means of rotational angiography (3DRA). To limit radiation burden, low-dose, noisy 3DRA image datasets have to be used. Our aim was to develop an algorithm combining information of several cardiac phases to filter out noise, enabling accurate semi-automatic segmentation (SAS) and generation of multi-phase segmentation surfaces. Methods and Results: We explored non-rigid interphase registration (IPR) using image warping and subsequent image averaging of 4 cardiac phases in low-dose 3DRA images from 5 porcine experiments, acquired with a novel protocol of slow atrial pacing. IPR parameter settings were optimised against manual delineations of the LVs using a score (Q) composed of standardised similarity measures. SAS was done for varying voxel intensity thresholds (ISO). Figure A shows a 4D posterior view sequence of 4 LV phases constructed with and without IPR, after SAS at ISO = 0 relative to optimal ISO. Relevant structures are the apex (1), LV inflow (2), LV outflow tract (3) and posterior papillary muscle (4). Distances to the manual delineations were reduced to 3 mm for 95.6 ± 2,7% of model surfaces (d3mm) at optimal ISO with IPR. Post-SAS IPR and non-IPR models were compared using 3 quality measures (Q; d3mm and Hausdorff Distance [HD, reflecting maximum error]). Improved quality was proven by significant increases in d3mm (illustrated in Figure B for the experiment of Figure A) and Q irrespective of ISO (mean increase at optimal ISO was 7.75% (95%CI 4.60-10.90, p<0.0001) for d3mm and 7.57% (95%CI 4.65-10.50, p < 0.0001) for Q). HD decreased significantly (-21.35%; 95%CI -18.61—24.10, p<0.0001). 4D model generating time was ±11.5min with IPR vs. ±22min without. CARDIAC IMAGING Proπireni saaeetak / Extended abstract

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