3D Mapping Research Articles

Procedural findings and follow-up results of catheter ablation of atrial fibrillation in patients after radiation therapy for breast cancer

Abstract Backround Data on breast cancer radiation therapy (RT) associated atrial cardiomyopathy and its potential role in the pathophysiology of atrial fibrillation (AF) is very limited. Objectives To investigate the effect of breast cancer radiotherapy (RT) on atrial cardiomyopathy and its possible role in the pathophysiology of atrial fibrillation. What is the therapeutic success of antral pulmonary vein isolation (PVI) with possible substrate modifications (CFAE) in patients with breast cancer radiation therapy and paroxysmal or persistent atrial fibrillation. Methods We searched the institution’s data base for patients who received RT for breast cancer and underwent subsequently 3D mapping guided AF ablation. Intraprocedural mapping data and short- and long-term results of ablation were evaluated according to "no low voltage" and "low voltage" present. Low voltage amplitudes in bipolar electrograms were defined as <0.5 mV for endocardial maps created during SR and <0.3mV during AF. Ablation strategy comprised pulmonary vein isolation (PVI) ± additional substrate modification according to the mapping results. Follow Up (FU) was evaluated using repetitive 7-days Holter ECG and clinical visits. Results We included 45 patients (all female, 70.9±7.2 years) with paroxysmal or persistent AF (n=18 and n=27). In 3D mapping, 60% of the patients (27/45) showed left atrial low voltage (LV group) with the majority showing low voltage in the anterior wall of the left atrium (LA) in 18 of 45 patients (40%). PVI with ablation of complex fractionated signals (CFAE) was predominantly performed (18/27). After one ablation, 33.3% (9) of the patients in the LV group were recurrence-free and after an average of 1.9 ablations, freedom from recurrence was achieved in 21 patients with low voltage (77.8%). In 18 patients, no low voltage was detected (NLV group) and PVI only was performed in the majority (14/18). In this NLV group, 61.1% (11) of the patients were recurrence-free after one ablation and freedom from recurrence was achieved in 72.2% (13) after an average of 1.2 ablations. Conclusion Thoracic radiation therapy in patients with breast cancer can lead to low voltage in the LA with the predominant low voltage location being the anterior wall of the LA. An extended ablation strategy (PVI & CFAE) can show good treatment options in these patients with atrial fibrillation, with high freedom from recurrence after a mean of two ablation procedures.Freedom from recurrence after ablationCharacteristics of left atrium (LA)

The correlation between left atrium voltage mapping and 3D late gadolinium enhancement cardiac magnetic resonance imaging findings in naive AF ablation candidate

Abstract Introduction The extent of the efficacy of late gadolinium enhancement cardiac MR (LGE-CMR) in depicting left atrial (LA) fibrosis in atrial fibrillation (AF) patients, compared to invasive Electroanatomical Mapping (EAM), is ongoing research field, while the highest degree of accuracy found when using ADAS program. Earlier studies focused mainly on post-ablation patients, employing segmentation (quality) and point-by-point (PBP) comparison methods. The non-invasive LGE-CMR-based fibrosis map shows promise for preprocedural planning and real-time guidance. Aim Evaluate LGE-CMR-based LA fibrosis precision in ablation-naïve AF patients using ADAS software, comparing it to the gold standard EAM using CARTO-3, in both qualitative and quantitative methods. Methods Patients planned for first CARTO-based AF ablation, undergoing pre-ablation LGE-CMR. 3D substrate atrial maps were generated via ADAS based on LGE-CMR (CMR-fib) and via CARTO as EAM. Normal range LA voltage was defined by Image Intensity Ratio of 1.2-1.32 on ADAS and by 0.2-0.5mV on Carto. Comparison methods, qualitative segmentation and PBP quantitative, with EAM serving as the gold standard. Results 24 naive patients included in the study (mean age 63.5 ± 10.9 yrs; 7 females, 15 paroxysmal AF, 17 maps during sinus). Segmental qualitative analysis (384 segments) showed 77% scarred segments, predominantly small scars (up to ⅓ segment). Compared with EAM, the CMR had 68.4% agreement, with 80.4% sensitivity, 78% PPV, 36.6% specificity, 32.6% NPV , kappa 0.139 AUC 0.567. Better agreement was found for dense scar. PBP quantitative comparison (41,345 points) demonstrated 50% scarred points, with 89% accuracy between EAM and CMR, with 49.6% sensitivity, 99.7% specificity, 99.5% PPV, and 73.5% NPV kappa 0.53, AUC 0.747. In both methods, agreement was worse for LA roof and best for AP and septal wall. Conclusion LGE-CMR tends to underestimate scar presence in naive patients compared to EAM, potentially due to baseline voltage scars, which are less dense compared to iatrogenic scar, the voltage criteria for scar in literature. Sensitivity is higher in segmental comparison, while specificity is superior in PBP, consistent with expectations of minimizing the size of comparison (from a segment to point). Hence, qualitative segmental method is better when assessing overall scarring, while PBP for assessing smaller specific areas. PBP comparisons exhibit less bias than segmental comparisons, which are overly sensitive to small scars. The diminished reliability of the LA roof is probably due to the margin of the CMR scan. Our study result regarding low sensitivity and high specificity of PBP aligns with a prior study investigating naïve patients through PBP comparisons, highlighting the need for a larger-scale study to assess LGE-CMR accuracy, considering various wall thicknesses and establishing scar thresholds on ADAS and CARTO software, for ablation-naïve patients with LA body scars.PBP projection on LA bodyAUC for PBP comprasion

The long-term outcome of pulmonary vein isolation in paroxysmal atrial fibrillation is significantly influenced by diabetes mellitus in general as well as by an antidiabetic therapy

Abstract Introduction Over the last decades pulmonary vein isolation became a cornerstone in the interventional treatment of paroxysmal atrial fibrillation. Postprocedural recurrences of atrial fibrillation are present in patients with and without concomitant cardiovascular diseases. Purpose The aim of this study was to assess the influence of diabetes mellitus and an antidiabetic therapy on the long-term outcome, defined as freedom of atrial fibrillation, of pulmonary vein isolation in patients with paroxysmal atrial fibrillation Methods All patients underwent pulmonary vein isolation using the combination of a radiofrequency ablation catheter, a pulmonary mapping catheter and a 3D electroanatomic mapping system. Every procedure was carried out according to current clinical and scientific standards. Procedural, clinical and follow-up data were stored for later statistical analysis. All patients received 4 follow-ups in total. In the first 12 postprocedural months patients were followed up after 3, 6 and 12 months. Furthermore, there was one long-term follow-up up to 6 years after the procedure. Results A total of n=1282 patients were included in the study. 39.2% of the patients were female and 60,8% were male. At the timepoint of the procedure the mean age was 63.7 years. The mean follow-up time was 2.2 years. For n=1144 of the included patients the presence respectively the absence of diabetes mellitus was documented. 8.0% (n=92) of these patients had the diagnosis of diabetes mellitus, from which 73.9% (n=68) were and 26.1% (n=24) were not under an antidiabetic therapy. Regarding the long-term outcome, patients without diabetes mellitus had significantly better results (log rank p=0.039). The according Kaplan-Meier-Analysis is shown in figure 1. Patients with diabetes mellitus were significantly older (69.5 years) when compared to patients without diabetes mellitus (63.1 years). However, when data was adjusted for age and gender, diabetes mellitus was still an independent, significant predictor of the recurrence of atrial fibrillation after pulmonary vein isolation. In addition, diabetics under an antidiabetic therapy had a significantly better long-term outcome than the untreated ones (log rank p=0.011). Figure 2 shows the according Kaplan-Meier-Analysis. Conclusion Diabetes mellitus has a significant influence on the long-term outcome of pulmonary vein isolation in patients with atrial fibrillation (log rank p=0.039). Patients without diabetes mellitus showed significantly better outcomes when compared to patients with diabetes mellitus also when adjusting the data for age and gender. Furthermore, the presence of an antidiabetic therapy in diabetics influences the long-term outcomes significantly (log rank p=0.011).

Graph-based robust 3D point cloud map merging approach for large scale

Graph-based robust 3D point cloud map merging approach for large scale

Mechanical wave velocities in acute myocardial infarction: an exploratory study using three-dimensional high frame rate echocardiography

Abstract Background Evaluation of cardiac function is crucial for management of patients with acute myocardial infarction (AMI). Recently, high frame rate (HFR) echocardiography has enabled identification of fast-propagating mechanical waves (MW) within the myocardium. These waves have the potential to offer unique insights into myocardial tissue properties, including edema and fibrosis. However, the potential of 3D HFR echocardiography to accurately quantify MW velocities and thereby assess myocardial stiffness in AMI patients remains unexplored. Purpose To assess the feasibility of a novel method for estimating MW velocities using 3D HFR echocardiography in patients with AMI compared to healthy controls. Methods Twenty patients with first time ST-elevation myocardial infarction were included within 48 hours after reperfusion therapy. We used a commercially available ultrasound scanner to acquire conventional 3D high-quality (~20 frames per second) acquisitions and subsequent 3D HFR recordings (~820 frames per second). The high-quality recording was used to extract a myocardial mask to define the region of interest in the HFR acquisition to detect the atrial kick wave and generate a comprehensive 3D map of MW propagation and velocities. We compared MW velocities between these patients and twenty age- and sex-matched healthy controls. Results MW velocities were successfully measured in 93% of participants (17 patients and 20 controls). Global MW velocities were significantly higher in AMI patients compared to healthy controls (2.1±0.6m/s vs. 1.5±0.2m/s, p<0.001). Territorial values, corresponding to the theoretical perfusion area of the three main coronary arteries, were significantly higher in infarct-related territories in patients when compared to same territories in controls for all coronary territories: Right coronary artery: 1.9±0.7 m/s vs. 1.4±0.3m/s, p<0.05; Circumflex artery: 3.1±1.5m/s vs. 1.7±0.4m/s, p<0.01; and Left anterior descending artery: 1.8±0.5m/s vs. 1.4±0.2m/s, p<0.01. Conclusions Estimation of MW velocities using a novel 3D HFR echocardiography method was feasible in most patients with AMI and all healthy controls. MW velocities were higher in patients compared to healthy controls and infarcted compared to non-infarcted coronary territories. These findings confirm the potential of non-invasive myocardial tissue characterization by MW imaging.Boxplot of MW velocities3D HFR MW visualisation

Atrial pace mapping with automatic intracardiac pattern matching for non-pulmonary vein trigger ablation: accuracy and feasibility

Abstract Atrial pace mapping (APM) is an alternative method to localize non-pulmonary vein (non-PV) triggers of atrial fibrillation(AF) that are otherwise not eligible for activation mapping due to their instability. The technique applies pattern matching of p-waves and intracardiac signals of atrial trigger and pacing from the site of the suspected origin. A new automated algorithm for intracardiac (IC) pattern matching was recently introduced into the 3D mapping system using the unipolar signal of the reference catheter. The study aims to assess the accuracy and feasibility of APM using IC-pattern matching for localizing non-PV triggers. Methods We assessed the precision of APM using a single chamber and double chamber reference in 20 patients who underwent index pulmonary vein isolation. APM was performed at the anterior and posterior wall of the left atrium (LApost, Laant) and the posterior and lateral wall of the right atrium (Rapost, Ralat). The first pacing point was declared as the origin. The IC-pattern matching algorithm was applied to calculate the similarity of the IC-pattern of the origin to the paced IC-pattern across various distances. The distribution of IC-pattern similarities was analyzed in the Python environment. The feasibility of APM was tested in patients who underwent REDO ablation of AF if all PVs were isolated and no low-voltage substrate was detected. The induction protocol for non-PV triggers included programmed and burst atrial pacing, high-dose isoproterenol, and adenosine infusion. If the IC pattern of the trigger was reproducible, the IC pattern matching was conducted. Ablation was performed at the site of the best IC-pattern matching. Results Atrial PM with IC-pattern matching and a single referent catheter showed lower precision in the RA lateral region (the median[Q1; Q3 ]area of 5% best matching score 1.48 [0.76; 2.01], 0.62[0.15; 1.06], 0.6[0.38; 1.19] and 5.68[2.89; 11.1] cm2 for LApost, LAant, RApost, RAlat accordingly, p = 0.0316). IC-pattern matching with double referent catheter showed high precision at all four anatomical regions (the median [Q1; Q3] area of 5% best matching score 0.126 [0.0879; 0.356], 0.486 [0.205; 0.717], 0.269 [0.198; 0.719], and 0.257 [0.0740; 0.572] cm2 for LApost, LAant, RApost, RAlat accordingly, Fig. 1). Seven out of 37 patients referred to REDO ablation had all PV isolated and absence of low-voltage substrate. In 3 of them, sustained tachycardias (AVNRT, focal atrial tachycardia and typical atrial flutter) were induced, mapped, and ablated. Non-sustained FAT from the RA posterior wall and PAC in the RA septum were induced under the high-dose isoproterenol infusion in two patients. Atrial pace mapping with double chamber referent and successful ablation of these non-PV triggers were performed (Fig.2). Conclusion The atrial pace mapping of non-PV triggers employing the automatic intracardiac pace mapping algorithm is feasible with high accuracy if a double-chamber referent is used.Accuracy of atrial pace mappingNon-PV trigger pace mapping

Collision mapping enables accurate localization of the slow pathway in atrioventricular nodal reentrant tachycardia

Abstract Introduction Atrioventricular Node Reentry Tachycardia (AVNRT) is commonly treated with catheter ablation, with high success and low complication rates. However a small risk of complete AV block still remains. Recent studies could show that using collision map is a feasible approach in mapping the slow pathway. The aim of the current study is to show a reduction of the total ablation points needed to modify/ablate the slow pathway using the collision mapping compared to conventional 3D mapping guided slow pathway modulation/ablation and therefore minimize the risk of a complete heart block. Methods Patients diagnosed with AVNRT (n = 24) underwent collision mapping for slow pathway identification, compared to a historical cohort (n=76) using conventional mapping. For collision mapping a dynamic visualization of atrial propagation during sinus rhythm was condcted. Two propagation fronts were observed to collide at the triangle of Koch, one propagation through the slow and one through the fast pathway. The designated collision zone was considered ideal for catheter ablation (Figure 1). The endpoint after ablation in both groups was non-inducibility of AVNRTs. Results After propensity score matching the collision mapping group needed significantly fewer ablation impulses (2 (IQR 1 - 5) vs. 6 (IQR 2,5 - 11,5) p = 0.002) and shorter ablation time (p < 0.001) compared to the conventional group (Table 1). No significant differences were observed in procedure time (p = 0.209), fluoroscopy time (p = 0.296), or dose area product (p = 0.391). Conclusion Collision Mapping in AVNRT ablation showed a notable reduction in ablation points, suggesting enhanced procedural efficiency and safety.Figure 1Table1

Long-term patient clinical benefits and healthcare utilization after pulsed field ablation in paroxysmal atrial fibrillation: sub-analyses from the multicenter inspIRE trial

Abstract Background/Introduction The treatment of atrial fibrillation (AF) with pulsed field ablation (PFA) aims to prevent AF recurrence while reducing complications from the ablation modality. Similar to thermal ablation, PFA has proven to be safe and effective for treatment of paroxysmal AF (PAF); however, there is scarce evidence on patient-related clinical benefits, including healthcare utilization, using this new energy modality. Purpose The objective of this study is to assess long-term clinical improvements in patient care, symptoms, and quality-of-life (QOL) after PFA ablation in PAF. Methods InspIRE was a multicentre study evaluating the safety and efficacy of variable loop PFA catheters integrated with a 3D mapping system for treatment of symptomatic PAF. Patients were followed for up to 12 months for the following QOL and healthcare utilization endpoints: Atrial Fibrillation Effect on Quality-of-Life (AFEQT) score, Class I/III AAD utilization, repeat ablation, incidence of direct current cardioversion (DCCV), and cardiovascular (CV) hospitalization. Post-hoc Kaplan-Meier estimates for clinical benefit success at 12 months were provided. Success was defined as composite freedom from occurrence of the following events post-blanking: repeat ablation, CV hospitalization, AAD utilization, and DCCV post-blanking. Predictors of clinical benefit success were explored via multivariate logistic regression analysis. Results A total of 186 enrolled patients (59±10 years; 70.0% male; CHA2DS2-VASC score 1.3±1.2) underwent PVI. Compared to baseline: 1) improvements in the AFEQT composite score were seen at 12 months (P<0.001); 2) Class I/III AAD use was reduced from 81.7% to 20.1% at 6-12 months (P<0.05); and 3) the proportion of subjects with DCCV decreased from 13.7% up to 12 months before the index procedure to 3.3% up to 12 months after the index procedure (P<0.001, Figure 1). Minimal clinically important difference in QoL (≥5 points improvement in AFEQT) was achieved in 85.2% of patients. Patients free from 12-month AF/AT/AFL recurrence (asymptomatic and symptomatic) had significantly greater improvements in AFEQT scores from baseline to 12 months versus those with recurrence (P=0.01). The clinical benefit success rate at 12 months was 87.5% (Figure 2). Patients who failed the clinical benefit endpoint were counted, including those with repeat ablation (7.5%), those on new or higher dose of AAD (6.5%), those hospitalized for CV (4.8%), and those who had DCCV post-blanking (1.6%). Multivariate logistic regression analysis showed that left ventricle ejection fraction <60% (OR: 0.22; 95% CI: 0.08-0.62; P<0.05) and incidence of diabetes (OR: 7.25; 95% CI: 2.00, 26.3; p<0.05) were associated with a higher risk of clinical benefit failure. Conclusions PFA ablation of PAF patients led to a clinical benefit success rate of 87.5%, with clinically meaningful improvement in QOL, as well as a reductions in AAD use, cardioversion, and hospitalization.Figure 1.Improvements in QoL and HealthFigure 2.Kaplan-Meier Analysis of Time

Novel approach of slow pathway ablation in common atrioventricular nodal reentrant tachycardia by peak frequency map

Abstract Background It is difficult to visualize slow pathway in atrioventricular nodal reentrant tachycardia (AVNRT) even with recent high-density mapping. This could be because the slow pathway potential is buried by the potential of atrial working cells during sinus rhythm and tachycardia. In other words, it is extremely difficult for conventional 3D mapping systems to annotate slow pathway potential even though the histological run of slow pathway is known .[1], [2] Purpose The purpose of this study is to visualize the atrial myocardial junction of rightward inferior extension by the peak frequency map of Ensite X in common AVNRT and to evaluate whether relative high frequency (HF) sites in low voltage area extending from Koch's triangle to tricuspid annulus (TA) is effective targets of slow pathway ablation and the characteristics of junctional rhythm (JR) after radiofrequency application. Methods This study is single-center prospective cohort study. In 37 consecutive common AVNRT patients, novel approach and conventional approach of slow pathway ablation were performed in 17 and 20 patients, respectively. The conventional approach is anatomical and electrophysiological approach. Peak frequency map was performed during sinus rhythm with HD-grid catheter in novel approach patients. A frequency scanning is performed to locate relative HF sites on the tricuspid annulus. Radiofrequencey application is 30 W, 30-60 sec, and the end point was no inducibility or until one echo under load of isoproterenol. Results The success rate was 100 % with two approaches. The relative HF sites in low voltage area were distributed at the TA side from 4 to 5 o'clock in all novel approach patients, mean peak frequency in success site was 419 ± 87 Hz. The distance to His bundle from success site was farther (24.8 ± 4.9 vs. 12.8 ± 4.4 mm, p<0.001), JR was slower (93 ± 14 vs. 118 ± 10 bpm, p=0.013), time to JR occurrence was shorter (3.0 ± 1.3 vs. 7.6 ± 4.6 sec, p=0.003), and elimination rate of jump up (78 % vs. 40 %, p=0.06) was higher in novel approach. Conclusions The relative HF sites in low voltage area at TA side from 4 to 5 o'clock by peak frequency map could be novel target of slow pathway ablation with high success rate and sufficient safety and efficiency.peak frequency map

3D Map Combined with Transthoracic Echocardiography for Ablation of Premature Ventricular Contractions/Ventricular Arrhythmia from Papillary Muscle: A Technical Report.

Ventricular arrhythmias originating from the papillary muscle of the ventricles are complex clinical problems. Catheter ablation has the potential to cure these arrhythmias. However, the procedure is usually challenging due to the specific anatomy, catheter instability and difficulty in localization of the origin of the arrhythmias. Intracardiac echocardiography (ICE) has been reported to be the suitable imaging method for assessing the location of focus in papillary muscles. We used transthoracic echocardiography (TTE), as a noninvasive cost-effective imaging supporting modality, in combination with 3D mapping to guide the exact localization and successful ablation of papillary muscle-originating premature ventricular contractions (PVCs).

Stereo and LiDAR Loosely Coupled SLAM Constrained Ground Detection.

In many robotic applications, creating a map is crucial, and 3D maps provide a method for estimating the positions of other objects or obstacles. Most of the previous research processes 3D point clouds through projection-based or voxel-based models, but both approaches have certain limitations. This paper proposes a hybrid localization and mapping method using stereo vision and LiDAR. Unlike the traditional single-sensor systems, we construct a pose optimization model by matching ground information between LiDAR maps and visual images. We use stereo vision to extract ground information and fuse it with LiDAR tensor voting data to establish coplanarity constraints. Pose optimization is achieved through a graph-based optimization algorithm and a local window optimization method. The proposed method is evaluated using the KITTI dataset and compared against the ORB-SLAM3, F-LOAM, LOAM, and LeGO-LOAM methods. Additionally, we generate 3D point cloud maps for the corresponding sequences and high-definition point cloud maps of the streets in sequence 00. The experimental results demonstrate significant improvements in trajectory accuracy and robustness, enabling the construction of clear, dense 3D maps.

Ultraviolet extinction correlation with 3D dust maps using white dwarfs

ABSTRACT Accurate astrometric and photometric measurements from Gaia have led to the construction of 3D dust extinction maps which can now be used for estimating the integrated extinctions of Galactic sources located within 5 kpc. These maps based on optical observations may not be reliable for use in the ultraviolet (UV) which is more sensitive to reddening. Past studies have focussed on studying UV extinction using main-sequence stars but lack comparison with 3D dust maps. White dwarfs with well-modelled hydrogen-dominated (DA) atmospheres provide an advantage over main-sequence stars affected by magnetic activity. In this work, we study the variation of UV extinction with 3D dust maps utilizing Hubble Space Telescope (HST) and Galaxy Evolution Explorer (GALEX) observations of DA white dwarfs located within 300 pc. We used HST COS spectroscopic data of 76 sightlines to calculate the optical extinction from Si ii column densities and validate our results with the kinematic model predictions of the local interstellar medium. Also, we combined GALEX and Gaia photometric observations of 1158 DA white dwarfs to study UV reddening by comparing observed and modelled colour–colour relations. We calculated GALEX non-linearity corrections and derived reddening coefficients [$R(NUV-G)=6.52\pm 1.53$ and $R(FUV-G)=6.04\pm 2.41$] considering their variations with optical extinction ($\rm{A_{V}}\lt 0.1$ mag), and found them to be in good agreement with known extinction laws. HST analysis suggests a positive bias of 0.01–0.02 mag in the optical extinction from 3D maps depending on the Galactic latitude. These results independently confirm the validity of 3D dust maps to de-redden the optical and UV observations of white dwarfs.

Motion and anatomy dual aware lung ventilation imaging by integrating Jacobian map and average CT image using dual path fusion network.

Deep learning-based computed tomography (CT) ventilation imaging (CTVI) is a promising technique for guiding functional lung avoidance radiotherapy (FLART). However, conventional approaches, which rely on anatomical CT data, may overlook important ventilation features due to the lack of motion data integration. This study aims to develop a novel dual-aware CTVI method that integrates both anatomical information from CT images and motional information from Jacobian maps to generate more accurate ventilation images for FLART. A dataset of 66 patients with four-dimensional CT (4DCT) images and reference ventilation images (RefVI) was utilized to develop the dual-path fusion network (DPFN) for synthesizing ventilation images (CTVIDual). The DPFN model was specifically designed to integrate motion data from 4DCT-generated Jacobian maps with anatomical data from average 4DCT images. The DPFN utilized two specialized feature extraction pathways, along with encoders and decoders, designed to handle both 3D average CT images and Jacobian map data. This dual-processing approach enabled the comprehensive extraction of lung ventilation-related features. The performance of DPFN was assessed by comparing CTVIDual to RefVI using various metrics, including Spearman's correlation coefficients (R), Dice similarity coefficients of high-functional region (DSCh), and low-functional region (DSCl). Additionally, CTVIDual was benchmarked against other CTVI methods, including a dual-phase CT-based deep learning method (CTVIDLCT), a radiomics-based method (CTVIFM), a super voxel-based method (CTVISVD), a Unet-based method (CTVIUnet), and two deformable registration-based methods (CTVIJac and CTVIHU). In the test group, the mean R between CTVIDual and RefVI was 0.70, significantly outperforming CTVIDLCT (0.68), CTVIFM (0.58), CTVISVD (0.62), and CTVIUnet (0.66), with p<0.05. Furthermore, the DSCh and DSCl values of CTVIDual were 0.64 and 0.80, respectively, outperforming CTVISVD (0.63; 0.73) and CTVIUnet (0.62; 0.77). The performance of CTVIDual was also significantly better than that of CTVIJac and CTVIHU. A novel dual-aware CTVI model that integrates anatomical and motion information was developed to synthesize lung ventilation images. It was shown that the accuracy of lung ventilation estimation could be significantly enhanced by incorporating motional information, particularly in patients with tumor-induced blockages. This approach has the potential to improve the accuracy of CTVI, enabling more effective FLART.

Modified ICP based Framework for 3D Localization and Mapping in GNSS-denied Environments using LiDAR

Abstract. Lidar odometry and mapping has emerged as fundamental technology in various fields, including accurate positioning and mapping, autonomous vehicles, robotics, and environmental monitoring. The ability to create accurate maps and calculate trajectories is essential for localization and navigation in complex environments, particularly in scenarios where GNSS signal are unavailable. In this context, we propose a novel method for simultaneous localization and mapping (SLAM) specifically designed for GNSS-denied environments and without the need for high-accuracy ranging or inertial measurement units (IMUs). Our approach aims to address the challenges posed by GNSS-denied environments and the cost constraints associated with using multiple sensors. By using only lidar sensors, specifically the Velodyne VLP 16 sensor, we offer a cost-effective solution. Our method utilizes a modified version of the Iterative Closest Point (ICP) algorithm to handle consecutive lidar scans seamlessly. In addition to our method, we conducted thorough accuracy assessments on the created map. The reason behind extensive accuracy evaluation is to ensure the quality of registration. By comparing alignment between the features of different frames within the map and determining the error between the registered features and the original, we gain a more comprehensive understanding of registration quality.

Efficient Multi-floor Indoor Mapping with A Versatile Rotating LiDAR System

Abstract. Light Detection And Ranging (LiDAR) technology has provided an impactful way to capture 3D environmental map. However, consistent mapping in sensing-degenerated and perceptually-limited scenes (e.g. multi-story buildings) or under high dynamic sensor motion (e.g. rotating platform) remains a significant challenge. To this end, an efficient multi-floor indoor mapping system is proposed in this paper utilizing a versatile rotating LiDAR platform. In the front end, measurements from motor, IMU and LiDAR are tightly integrated to track the fast motion state of system, based on iterative Error State Kalman Filter (ESKF). Then linear and planar features are extracted from the point cloud map voxelized with adaptive resolutions. A sliding-window-based batch optimization is performed to simultaneously optimize the states of local frames with reference to the map consistency. In the experiments, we investigated the influence of rotating speed on the mapping performance as well as the superiority of rotating mechanism when compared to standard LiDAR setup. Moreover, comparative studies with one of the SOTA work, FAST-LIO2, have shown the competitive mapping results in multi-floor indoor environments.

A Spatiotemporal Empowerment Framework for China’s National 3D Mapping Program 3dRGLM

Abstract. China has launched a national 3D mapping program to build 3D Realistic geospatial Landscape Model (3dRGLm) over the whole country, covering both cities and countryside. The 3dRGLM is a digital description and representation of the real 3D geospatial spaces, and is defined as a new generation geospatial data product with 3D structures, realistic scenes, and geospatial entities. Such a national or local 3dRGLm will set up a digital 3D realistic geospatial space which can facilitate the vital connection with the real geospatial space, and will serve as a new generation of geospatial information infrastructure for our society. With the acquisition of complex 3D spatial data continues to advance, managing and utilizing the massive volumes of 3D data to provide spatiotemporal empowerment applications has become a significant technological challenge. This paper analyzes the technical characteristics of 3d realistic geospatial landscape model, and then proposes the main content and basic structure of a 3d realistic geospatial landscape model database, as well as the spatiotemporal service empowerment methods based on the database. Finally, a case analysis is provided to serve as a reference for the construction and application of 3d realistic geospatial landscape.

OFDM Transmission in Rayleigh Fading Channel for S-Box and 3D Chaotic Maps Based Encrypted Image

Data encryption is an important part of the communication system. The Chaos essential properties, make it a crucial candidate for encryption applications. There is a compromise between complexity and security in previous studies. In this study, high security was achieved with low complexity. This paper proposed a 3D chaotic map and S-Box has been cascaded to get a high efficiency as complex algorithms or multi-iteration schemes. The first stage is ciphering using 3D cat-map, the second stage is S-box based on 3D henon map, while the third stage is another ciphering stage using 3D henon map. In this study, various encryption techniques, including cipher algorithms and substitution box, are combined with the OFDM system to establish a secure image transmission over a Rayleigh fading channel. QPSK modulation is used to ensure the simplicity of the proposed system. Six gray images are used, Lena, the cameraman, Barbara, Baboon, pepper and Elaine for testing and comparing with previous works. Security analysis is performed to evaluate the quality and security of the encryption process, the entropy value reach 7.99, correlation coefficient is around zero and the histogram is uniform. In addition, the key size is 2630. For image transmission evaluation, the PSNR and BER are utilized and it reached 10-5 for BER. According to the statistical results, the proposed image encryption scheme is secure and efficient.

Detecting Indoor Tiny Autonomous Malicious Drones within Critical Infrastructures: An Innovative Algorithm based on Harmonic Radar-Equipped Mini-Drones

Critical infrastructures play a central role in the welfare of contemporary societies and they should properly function 24/7. Since their role is so important, they regularly become targets of malicious parties, terrorists, industrial spies, and even hostile governments. In this paper, the scenario of cyber or physical attacks to CIs from tiny autonomous malicious drones is analyzed. In particular, this work focuses on indoor spaces, protected by mini-drones. The mini-drones are equipped with harmonic radar and run a novel algorithm, which guides them to scan the whole area. Assuming that the malicious drones behave as non-linear systems, the mini-drones transmit signals and analyze the received signals, creating a non-linear system 3D location map for the whole space. In the consecutive scans, any changes on the 3D location map indicate that the malicious drone has changed location. Simulated results and comparisons to state-of-the-art approaches exhibit the cost-effectiveness and time efficiency of the proposed scheme as well as its limitations.

Real-time, dense UAV mapping by leveraging monocular depth prediction with monocular-inertial SLAM

We present a dense and metric 3D mapping pipeline designed for embedded operation on-board UAVs, by loosely coupling deep neural networks trained to infer dense depth single images with a SLAM system that restores metric scale from sparse depth. In contrast to computationally restrictive approaches that leverage multiple views, we propose a highly efficient, single-view approach without sacrificing 3D mapping performance. This enables real-time construction of a global 3D voxel map by iterative fusion of the rescaled dense depth maps obtained via raycasting from the estimated camera poses. Quantitative and qualitative experimentations of our framework in challenging environmental conditions show comparable or superior performance with respect to state-of-the-art approaches via a better effectiveness-efficiency trade-off.

Charge density mapping demonstrates superiority in catheter ablation of post-surgical atrial tachycardias.

Atrial tachycardia (AT) frequently occurs after cardiac surgery or surgical ablation procedures. The novel charge density-based mapping system (CDM) provides global chamber mapping and can detect crucial pathways of conduction; therefore, it has potential added value in catheter ablation (CA) of post-surgical ATs. We aimed to test the hypothesis that CDM-guided CA procedures are safe, feasible, and may improve outcome compared to conventional sequential 3D mapping (CARTO)-based CA. Consecutive patients undergoing CA for post-surgical AT guided by CDM or CARTO were enrolled. Procedural safety and efficiency were analyzed. Acute success, one-year outcome was assessed. A total of 35 patients (mean age 60.8 ± 10.6 years, 42.9% female) underwent CA of AT using CDM (n = 20) and CARTO (n = 15). A total of 61 ATs were mapped (35 in CDM and 26 in CARTO group). Four patients had focal ATs, 22 macro re-entrant, and 8 patients had ATs with both mechanisms. No differences were found in procedural complication (CDM 3 vs. CARTO 1 patient, p = 0.61). There were no differences in procedure duration (185.9 vs. 147.9 min, p = 0.09), fluoroscopy dose (165.0 vs. 155.0 mGy, p = 0.31), RF application number (28.0 vs. 18.0, p = 0.17) or duration (1,251.5 vs. 1,060.0 s, p = 0.54). Acute success was 95.0% in CDM and 73.3% in CARTO group (p = 0.14). Cumulative AT recurrence rates were lower in CDM group compared to CARTO group (10.0% vs. 46.7%, p = 0.02). The CDM system is feasible. Our data suggest that patients treated with CDM-guided CA developed fewer AT recurrences as compared to CARTO-guided procedures.