| Transcatheter occlusion of left atrial appendage is an important way to prevent persistent atrial fibrillation in patients with cerebral embolism,due to the great variation of the left atrial appendage size and spatial form,evaluation of preoperative evaluation of left atrial appendage occlusion is essential for the intervention.Preoperative measurement of left atrial appendage occlusion mainly depends on transesophageal echocardiography,the spatial morphology is mainly accessed by CT angiography.With the appearance and rapid development of transesophageal three-dimensional echocardiography(3DTEE),the temporal and spatial resolution of ultrasound images has been significantly improved.At the same time,the application of ultrasonic image postprocessing technology has revealed a certain lag:common three-dimensional ultrasound imaging effect of conventional display cavity perspective and provide cardiac function and morphology of limited information,image information and more valuable is occluded or concealed.How to make full use of three-dimensional echocardiography in the clinical diagnosis and treatment is of great importance for 3DTEE.Since Charles Hull invented the 3D printer in the early of 1980s,3D printing technology developed rapidly in the automotive,aerospace,electronic products and other fields.3D printing is regarded as a major technological innovation manufacturing.Since 2000,3D printing has been used for t dental implants and custom-made prosthesis.In recent years,with the continuous development of technology,the heart 3D printing began to appea.Studies have shown that the cardiac 3D printing can significantly enhance the understanding of the pathological anatomy of the heart,guide the operation of complex and difficult cases,which is of great potential in the field of cardiac surgery and cardiac intervention.This study explores the new image postprocessing of 3DTEE imaging for the left atrial appendage occlusion and discuss the feasibility and clinical value of echocardiography 3D printing technology.To provide the basis for assessment of left atrial appendage occlusion preoperatively and occlusion strategy for the complex left atrial appendages.There are four parts in this study:Part 1:The role of Flexi Slice imaging by real time 3D Transesophageal Echocardiography in measurement of left atrial appendage in patients with atrial fibrillationPart 2:Volume Rendered Imaging of Three Dimensional Transesophageal Echocardiography with Grey Values Inverted in assessment of morphology of Left Atrial Appendage in patients with Atrial FibrillationPart 3:Guidance of Three-dimensional Printing Model of Left Atrial Appendage Derived from Transesophageal Echocardiography for Left Atrial Appendage ClosurePart 4:Establishment and assessment of an LAA occlusion preoperative simulation system based on 3DTEE and 3D PrintingPart 1:The role of Flexi Slice imaging by real time 3D Transesophageal Echocardiography in measurement of left atrial appendage in patients with atrial fibrillationObjectiveUsing Flexi Slice imaging by real time 3D Transesophageal Echocardiography(TEE)to measure left atrial appendage(LAA)in patients with atrial fibrillation,and compare with common multiplane TEE.MethodsForty-six patients with atrial fibrillation were performed 2-demensional and real time three dimensional TEE.Zero degree,forty-five degree,ninety degree and one hundred and thirty five degree plane were acquired by 2D TEE and Flexi Slice remolding.Maximum and minimum values of ostium of left atrial appendage were acquired in the short axis view of LAA by Flexi Slice remolding.ResultsCompared with 2D TEE,values acquire by Flexi Slice in measurement of LAA ostium showed no significant difference(P>0.05).The depth measurement by Flexi Slice in 45 and 90 degree plane showed significant difference with 2D TEE,(P-values were successively 0.045,0.002)and in 0 and 135 degree plane showed no difference.All values measured by 2D TEE and Flexi slices showed significant correlation.Bland-Altman plot showed that 94.29%of plots were among limits of agreement,which was(-2.5mm,2.9mm).The maximum values of LAA ostium values ranged from 30 to 160 degree,among which 87%(40/46 cases)distributed between 90 and 150 degree,and minimum values ranged from 0 to 160 degree,among which 85%(39/46 cases)distributed between 0 and 60 degree.ConclusionMeasurement of LAA can be well achieved by Flexi Slice imaging,which showed significant advantage compared with 2D TEE.Part 2:Volume Rendered Imaging of Three Dimensional Transesophageal Echocardiography with Grey Values Inverted in assessment of morphology of Left Atrial Appendage in patients with Atrial FibrillationObjectiveTo acquire volume rending images of left atrial appendage(LAA)chambers by three dimensional transesophageal echocardiography(3DTEE)using a novel image mode of Grey Values Inverted Imaging(GVI).This mode of imaging can achieve similar effects to cardiac computed tomography angiography(CCTA),and can assess morphology of LAAs accurately.Methods40 patients with Atrial Fibrillation were performed with TEE and Cardiac CT examination before intervention treatment.Three-dimensional Transesophageal Echocardiography images were acquired and were displayed as a gray values inverted mode.Threshold segmentation and Interactive segmentation were used to 3D digital replicas of LAA chambers.Morphology information including morphology type of LAAs and number of lobes and measurements of LAAs were recorded and were compared with CT-VR images.ResultsMorphology information and measurements were successfully acquired by CT and 3DTEE-GVI images in all 40 cases.The consistence of LAA morphology type by 3D-GVI and CT was 97.5%.The consistence of number of LAA lobes by 3D-GVI and CT was 92.5%.The measurements of long axis,short axis,area of ostiums of LAAs,and depth of LAAs by CT were larger than 3D-GVI(p<0.01).There were agreements between two methods of measurement.ConclusionLAA chambers can be reconstructed by 3D TEE-GVI,which can achieve similar VR effect to Cardiac CT.3DTEE-GVI promises to be one of the most effective methods in assessment of LAAs' morphology information for planning of LAA occlusion.Part 3:Guidance of Three-dimensional Printing Model of Left Atrial Appendage Derived from Transesophageal Echocardiography for Left Atrial Appendage ClosureObjectiveThis study aimed to investigate the feasibility of three dimensional printing LAA models from three dimensional transesophageal echocardiography(3D TEE)volume-rendered data and its value for guiding the placement of LAA occlusion device.MethodsTen patients with non-valvular atrial fibrillation(AF)were underwent TEE before LAA occlusion.3D full volume data and routine two dimensional images of the LAA were acquired.The 3DTEE data were post-processed by grey values inverted imaging and threshold segmentation to create volume rendered images of the LAA in STL format.The cardiac chamber model and the cardiac wall model of the LAA were printed out by 3D printer for the LAA morphology evaluation and measurement.Preoperative rehearsal was carried out on the printed 3D LAA models.ResultsIn all the patients,3DTEE full volume data of the LAA were successfully reprocessed and printed out.In terms of the LAA morphology classification based on cardiac chamber models there were 5 chicken wing,3 windsock,2 cauliflower.And there were 4 single-lobed,3 bi-lobed and 3 multi-lobed.The maximal ostium diameter and the depth of the main anchoring lobe were 20.30±3.53 mm and 28.26±5.51mm respectively,concordant well with the measurements of 2D TEE and CT.The LAmbreTM and the Lefort occlusion device could be implanted into the 3D LAA models for occlusion planning before the procedure.Occlusion success rate was 100%.Conclusion3D TEE full volume data is feasible and capable of creating LAA 3D models.3D models of LAA derived from 3D TEE have promising value in guiding the LAA occlusion procedure.Part 4:Establishment and assessment of an LAA occlusion preoperative simulatlion system based on 3DTEE and 3D PrintingObjectiveTo create an left atrial appendage(LAA)occlusion preoperative simulation system by three dimensional transesophageal echocardiography(3DTEE)and three dimensional printing(3DP),and to simulate the process of LAA occlusion including the selection and deployment of devices,leaks around devices and the compression rate of the devices in vitro.MethodsFifteen cases of left atrial appendage occlusion in patients with atrial fibrillation were selected in this study.Preoperative and intraoperative TEE was performed to acquire the volume data of LAA.Replicas of LAAs were created by 3DP.Then the simulation system was created by 3DTEE and the models.The models were scanned by 3DTEE to evaluate the accuracy of models,leaks around devices and the compression rate of the devices.The results were compared with intraoperative measurements.Results3DP models of 15 patients were created based on the 3DTEE data.There were no significant differences between measurements in models and in vivo by 3DTEE and there were agreements between these two methods.The compression rate of devices were higher in models than in vivo(P=0.04).Compression rate in models correlate with that in vivo(R=0.949 P<0.01).4 cases were observed with leaks in 3DP models and 6 cases were observed with leaks intraoperatively,the kappa value of agreement was 0.706.ConclusionsPreoperative exercise and evaluation of LAA occlusion can be acquired by the preoperative simulation system based on 3DTEE and 3DP,which can be an important supplement for preoperative preparation. |
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