Propagation Map Research Articles

Shear-wave elastography of canine patellar tendons in healthy dogs and the influence of stifle joint angle.

Elastography is a sonographic modality that measures tissue stiffness, a mechanical property of tissues, and a biomarker for disease. Canine musculoskeletal application to the patellar tendon has been limited to semiqualitative strain elastography. This prospective study aimed to quantitatively evaluate patellar tendon stiffness using shear-wave elastography with a color map superimposed over the tendon, a propagation map for quality control, and measurements at specific regions of interest in 16 clinically normal sedated dogs weighing 25kg or greater. Tendon stiffness using shear-wave elastography (SWE) was assessed at different stifle angles and in three regions to determine if angle and location affected stiffness. All dogs were screened with general and orthopedic exams, lateral stifle radiographs, and patellar tendon 2D ultrasound. Shear-wave elastography was performed from a long axis at various stifle angles at the proximal, middle, and distal tendon segments. Quality diagnostic SWE results varied significantly with stifle angle, and 150° of extension was the only angle found to be clinically useful based on the ease of obtaining measurable results and a quality control propagation wave. Patellar tendons were primarily stiff with a red color elastogram. The proximal and middle segments, measured at various angles, had a mean SWE velocity of 7.32±0.90m/s. Tendon stiffness did not differ along tendon length when measured in greater extension. However, stiffness decreased in the middle segment of the tendon at 150° when compared with 120°. This study establishes a quantitative baseline of normal patellar tendon stiffness to compare with pathologic states.

Shear wave trajectory detection in ultra-fast M-mode images for liver fibrosis assessment: A deep learning-based line detection approach

Stiffness measurement using shear wave propagation velocity has been the most common non-invasive method for liver fibrosis assessment. The velocity is captured through a trace recorded by transient ultrasonographic elastography, with the slope indicating the velocity of the wave. However, due to various factors such as noise and shear wave attenuation, detecting shear wave trajectory on wave propagation maps is a challenging task. In this work, we made the first attempt to use deep learning methods for shear wave trajectory detection on wave propagation maps. Specifically, we adopted five deep learning models in this task and evaluated them by using a well-acknowledged metric based on EA-Angular-Score (EAA) and task-specific metric based on Young s-Score (Ys) in the line-detection field. Furthermore, we proposed an end-to-end framework based on a Transformer and Hough transform, named Transformer-enhanced Hough Transform (TEHT). It took a wave propagation map as input image and directly output the slope of the shear wave trajectory. The framework extracts multi-scale local features from wave propagation maps, employs a deformable attention mechanism for feature fusion, identifies the target line using the Hough transform’s voting mechanism, and calculates the contribution of each scale through channel attention. Wave propagation maps from 68 patients were utilized in this study, with manual annotation performed by a rater who was trained as a radiologist, serving as the reference value. The evaluation revealed that the SLNet model exhibited F-measure of EA and Ys values as 40.33 % and 40.72 %, respectively, while the TEHT model showed F-measure of EA and Ys values as 80.96 % and 98.00 %, respectively. TEHT yielded significantly better performance than other deep learning models. Moreover, TEHT demonstrated strong concordance with the gold standard, yielding R2 values of 0.967 and 0.968 for velocity and liver stiffness, respectively. The present study therefore suggests the application of the TEHT model for assessing liver fibrosis owing to its superiority among the five deep learning models.

Voltage and propagation mapping: New tools to improve successful ablation of atrioventricular nodal reentry tachycardia.

Mapping system is useful in ablation of atrioventricular nodal reentry tachycardia (AVNRT) and localization of anatomic variances. Voltage mapping identifies a low voltage area in the Koch trianglecalled low-voltage-bridge (LVB); propagation mapping identifies the collision point (CP) of atrial wavefront convergence. We conducted a prospective study to evaluate the relationship between LVB and CP with successful site of ablation and identify standard value for LVB. Three-dimensional (3D) maps of the right atria were constructed from intracardiac recordings using the ablation catheter. Cut-off values on voltage map were adjusted until LVB was observed. On propagation map, atrial wavefronts during sinus rhythm collide in the site representing CP, indicating the area of slow pathway conduction. Ablation site was selected targeting LVB and CP site, confirmed by anatomic position on fluoroscopy and atrioventricular ratio. Twenty-seven consecutive patients were included. LVB and CP were present in all patients. Postprocedural evaluation identified standard cut-off of 0.3-1 mV useful for LVB identification. An overlap between LVB and CP was observed in 23 (85%) patients. Procedure success was achieved in all patient with effective site at first application in 22 (81%) patients. There was a significant correlation between LVB, CP, and the site of effective ablation (p = .001). We found correlation between LVB and CP with the site of effective ablation, identifying a voltage range useful for standardized LVB identification. These techniques could be useful to identify ablation site and minimize radiation exposure.

Non-invasive cardiac activation mapping and identification of severity of epicardial substrate in Brugada Syndrome: a case report

IntroductionIt has recently been shown that electrocardiographic imaging (ECGi) can be employed in individuals undergoing an ajmaline test who have Brugada Syndrome (BrS), to evaluate the extent of substrate-involved arrhythmia in the right ventricular overflow tract (RVOT). For the first time, we stratify the risk of sudden cardiac death (SCD) in BrS during ajmaline testing using the dST-Tiso interval (a robust predictor of the inducibility of ventricular arrhythmias (VAs) in the presence of drug-induced BrS type-1 pattern) in combination with ECGi technology.Case presentationWe studied a 48-year-old man with BrS ECG type-2 pattern and presence of J-wave without a family history of SCD but with a previous syncope. Transthoracic echocardiography and cardiac magnetic resonance imaging were performed, showing normal results. The ECG was performed to assess the novel ECG marker “dST-Tiso interval.” The 3D epicardial mapping of the RVOT surface was performed with the support of a non-contact cardiac mapping system in sinus rhythm during ajmaline infusion. The examination of the propagation map unveiled the presence of multiple conduction blocks in this pathologic epicardial region, and the conduction blocks were identified within the central part and/or near the boundary separating the normal and slow conduction areas.ConclusionThe dST-Tiso interval, which lies between the onset and termination of the coved ST-segment elevation and serves as a robust predictor of VA inducibility in cases of drug-induced BrS type-1 pattern, was utilized in conjunction with ECGi technology (employed for the non-invasive confirmation and identification of the pathological substrate area). This combined approach was applied to stratify the risk of SCD in BrS during ajmaline testing, alongside clinical scores.

Transcatheter ablation of atrioventricular nodal reentry tachycardia in children and congenital heart disease in the era of 3D mapping.

Atrioventricular nodal reentrant tachycardia (AVNRT) is a common supraventricular tachycardia in children and congenital heart disease (CHD) patients. Nowadays, in large enough children, chronic treatment for symptomatic and recurrent AVNRT episodes relies on transcatheter ablation. Indeed, many three-dimensional (3D) mapping strategies and ablation techniques have been developed and it helped to increase success rates and to reduce complications. Therefore, this study aimed to perform an updated comprehensive review of the available literature regarding contemporary management of AVNRT in children. A literature search was performed using Google Scholar, PubMed, Springer, Ovid, and Science Direct. We found that in recent times many investigations have demonstrated that 3D mapping systems allow to localize more precisely the ablation substrate, with minimal use of fluoroscopy. The most frequently employed mapping strategies are the low-voltage bridge strategy together with the search for the SP potential and the Sinus Rhythm Propagation Map with the identification of areas of Wave Collision or Pivot Points. For transcatheter ablation in pediatric settings, radiofrequency (RF) ablation was first used in the 1990s, while cryoablation was introduced in 2003 and nowadays represents the most used energy for AVNRT ablation in this population. Indeed, its specific features, such as reversible cryomapping, cryoadhesion and the precision in lesion delivery, made this technique very appealing to decrease complications and fluoroscopy time. As regards AVNRT in CHD patients, it represents the third most common form of arrhythmia in children with CHD. However, in this subgroup ablation remains challenging and experience limited, since anatomy may be atypical and the areas of ablation less predictable or less accessible.

Low voltage and low wave speed are rarely present outside the left atrium-pulmonary veins junction in paroxysmal atrial fibrillation but frequently present in persistent forms

Abstract Background and aim Multielectrode high-density catheters have enabled acquisition of comprehensive and dense maps of electrogram’s amplitude and timing. However, automated activation and voltage mapping are flawed by catheter orientation in relation to the wavefront activation. Omnipolar mapping technology (OT) uses both unipolar and bipolar signals to obtain OT signals and increases the accuracy of automatic point acquisition allowing for a high- density map in a quick and efficient way. The aim of this study was to automatically assess with OT, the left atrium (LA) voltage and wave speed propagation map in sinus rhythm (SR) according to the type of atrial fibrillation (AF). Methods We studied 14 consecutive patients referred for ablation of AF, either paroxysmal (PAF) (n=6) or persistent (Pers-AF) (n=8) using catheters with OT. Patients with Pers-AF were cardioverted, and a SR map was obtained before ablation in all patients and voltage and propagation wave speed maps were obtained. The cut-off for low voltage areas (LVAs) was less than 0.1 mV and for low wave speed (LWS) was less than 0.4 mm/ms. Results were compared according to the type of AF. Results The results are depicted in the Table. The median duration of AF in Pers-AF was 18 (5-24) months. Patients with Pers-AF had larger LA volumes and displayed presence of LVAs and LWS areas in 100% of cases in comparison with 17% and 33% of cases respectively for PAF patients (p=0.003 and p=0.015). Also, the total LVAs and LWS areas in cm2 were significantly higher, (p=0.001 and p=0.005)). The LVAs and the LWS areas were more frequently located outside the PV-LA junction in Pers-AF than in PAF, respectively 75% vs 0% and 88% vs 0%, p=0.010 and p=0.005 (Figure). Conclusions Patients with PAF never presented LVAs or LWS outside the PV-LA junction. On the contrary, patients with Pers-AF had frequently anatomical and electrophysiological abnormalities in the LA body. These findings may suggest the need for a wider ablation strategy in Pers-AF.Normal voltage in purple ; LWS in white

Clinical application of two dimensional shear wave elastography with a propagation map in evaluating liver fibrosis in patients with liver tumors.

This study aimed to evaluate the diagnostic performance of two-dimensional shear wave elastography (2D-SWE) with a propagation map in evaluating the degree of hepatic fibrosis in patients with liver tumors before resection. From January 2020 to April 2021, 128 patients with liver tumors were prospectively enrolled, including 20 benign liver tumors and 108 malignant liver tumors. 2D-SWE with a propagation map technology was used to measure the stiffness of liver parenchyma 2 cm away from the tumor. The median value of five measurements was used in this study. The stage of hepatic fibrosis was graded in accordance with Scheuer standard. Spearman correlation was used to analyze the correlation between liver fibrosis stage and the liver stiffness. Univariate and multivariate linear regression analyses were used to determine significant affecting factors for liver stiffness value. The diagnostic performance of 2D-SWE with a propagation map in predicting fibrosis stage was evaluated by receiver operating characteristic curve analysis. The median liver stiffness value in patients with benign liver tumors was lower than that in patients with malignant liver tumors (6.0 kPa vs. 9.4 kPa, p < 0.05). The median liver stiffness values in patients with primary liver cancer were higher than that in patients with benign liver tumors and other types of malignant liver tumors (9.6 kPa vs. 6.0 kPa, p < 0.05). The liver stiffness measured by 2D-SWE was highly correlated with the fibrosis stage confirmed by postoperative pathology (r = 0.834, p < 0.05). For the liver stiffness value, PLT,TB,ALB and fibrosis stage are significantly associated with liver stiffness. The median liver stiffness values in stages S0-S4 of fibrosis were 6.0, 7.2, 8.0, 9.4, and 12.6 kPa, respectively. The areas under the ROC curve of S≥1, S≥2, S≥3, and S = 4 as predicted by SWE were 0.932, 0.945, 0.945, and 0.916, respectively. According to the Youden index, the optimal critical values for predicting fibrosis S≥1, S≥2, S≥3, and S = 4 were 6.8 (sensitivity of 89.69% and specificity of 93.55%), 7.5 (sensitivity of 87.50 % and specificity of 95.00 %), 8.3 (sensitivity of 87.14 % and specificity of 87.93 %) and 9.8 (sensitivity of 79.55 % and specificity of 86.90 %) kPa. 2D-SWE with a propagation map could noninvasively and accurately predict the staging of liver fibrosis in patients with liver tumors before resection.

On the feasibility and performance of the ammonia/hydrogen/air rotating detonation engines

A series of numerical simulations were performed to investigate the feasibility and performance of the premixed ammonia/hydrogen/air rotating detonation engines. A 19 species and 80 reactions ammonia/hydrogen/air mechanism is adopted and validated for detonation simulations. The effects of injection total temperatures (T0) and ammonia/hydrogen equivalence ratios (φNH3 and φH2) are analyzed under a fixed global equivalence ratio of 1. The propagation map of rotating detonation waves is numerically outlined. The result indicates that a higher injection total temperature and a lower ammonia equivalence ratio are beneficial to the successful propagation of rotating detonation waves. The maximum φNH3 with successful propagation of rotating detonation waves reaches 0.6, achieved at T0 = 1000 K. High total temperatures and ammonia equivalence ratios can lead to lower detonation wave speeds. The detonation height is found to account for around 20%–36% of the engine axial length. The critical accommodated detonation cell number for successful propagation of rotating detonation waves is 5.9, below which the rotating detonation wave will have difficulty maintaining propagation. Mass-flow-averaged and area-averaged methods are adopted to evaluate the pressure gain performance of NH3/H2/air RDE. The results of the two methods both indicate that the total pressure gain is significantly affected by the injection total temperature but less affected by the equivalence ratio of NH3. In addition, it is found that NOx emission is dominated by NO. The NOx emission increases with increased injection total temperatures and ammonia equivalence ratios. Negligible NOx emission is produced in pure hydrogen-fueled RDE while it reaches the maximum (0.037) at φNH3 = 0.6 and T0 = 1000 K.

Voltage and propagation mapping: new tools to improve successful ablation of atrioventricular nodal reentry tachycardia

Abstract Funding Acknowledgements Type of funding sources: None. Background Ablation of atrioventricular nodal reentry tachycardia (AVNRT) has become the treatment of choice for AVNRT due to high success and low complication rate. A 3-D reconstruction of the atrial endocardial anatomy created by mapping system is useful because anatomic variances or unusual slow pathway locations may affect the effectiveness of classical anatomical approach. Voltage mapping is useful to identify a low voltage area in the Koch triangle (KT) called low-voltage-bridge (LVB); propagation mapping identifies the collision point (CP) of atrial wavefront convergence. These technique may be helpful to improve the localization of the slow pathway. Purpose Our purpose is to conduct a prospective study to evaluate the relationship of the propagation map to voltage mapping and successful site of ablation; moreover we would identify a cut-off value of LVB able to standardized the procedure. Methods Voltage maps of KT (at least 150 points) were obtained through the ablation catheter. Voltage values were adjusted until LVB was observed and classified in two types (Pic 1): Type I is a clear, large area; Type II is a narrow corridor or small areas. The collision point is the area in which the atrial wavefront during sinus rhythm collided on the propagation map indicating the area of slow pathway conduction. Ablation site was selected by LVB position or collision point, confirmed on anatomic position or AV ratio. Ablation of the slow pathway was performed using radio-frequency (RF) or cryotherapy. Results Eighteen consecutive patients were included; one patient was excluded because of inadequate voltage map. Ten patients were female. The median age was 51. In all patients inducible typical AVNRT was present. In 8 patients RF energy was used. Mean procedure time was 109 minutes; mean fluoroscopy time was 3,4 seconds (zero-fluoro procedure in 13 patients). Procedure success (no inducible AVNRT and no more than a single AV node echo beat) was achieved in all patient. No procedural complications were observed. No recurrence at 1 year follow up. The LVB was present in all patients; 9 patients had a type 1 LVB. Voltage map was created adjusting voltage high and low ranges in order to visualize LVB. Limited of LVB visualization is the leak of standard range of value for map creation. Post procedural evaluation identified standard cut-off of 0.3-1mv useful for LVB identification (only one patient had lower voltage range). The collision point was present in all patients. A correlation between LVB and CP was observed in 17/18 patients (Pic 2). In 16 patients successful ablation site was within 5mm of the wave collision. Conclusion In our prospective study, we found correlation between LVB and CP and the site of effective slow pathway ablation in most patients, and we identified a voltage range useful for standardized LVB identification during voltage mapping. Moreover, these techniques are useful to identify ablation site and minimize radiation exposure.

Evaluating the evolution of fiber-reinforced emulsified asphalt cold-recycled mixture damage using digital image correlation

ABSTRACT The cold recycled mixture has insufficient resistance to cracking, and the process of fracture is incompletely understood. This study used digital image correlation (DIC) technology and a semi-circular bending test to investigate the anti-crack performances and fracture propagation of basalt fiber-reinforced cold recycled mixture (BFCRM). The load-displacement, full-field strain, full-field displacement, displacement rate and crack propagation map were obtained to evaluate the BFCRM’s anti-crack performances. The control cold recycled mixture without fibers was also prepared for comparison. Meanwhile, the fracture process zone (FPZ) during loading were compared and quantitatively assessed by digital image correlation analyses, and the fiber distribution and microscopic features at fracture surface was observed by scanning electron microscopy. The results show that the formation of microcracks of BFCRM takes more time than that of the control group without fiber. Based on DIC observations, the basalt fibers maintain strong anti-crack performance in cold-recycled mixtures and reduce fracture damage. The fracture surface morphology also revealed that basalt fiber exhibited adsorption, bridging, anchoring, stability, and strengthening effects at micro/nano scale, which further improved anti-crack performance e and hindered crack development of cold recycled asphalt mixtures.

Using GIS techniques for modeling of anthropogenic noise propagation generated by a chainsaw in forest harvesting

Noise is an environmental pollution that negatively affects human health and reduces the performance of employees. Forest harvesting activities are one of the working environments where noise effect is intense. The most common equipment used in forest operations is chainsaw whose noise affects not only the operator but also the wildlife in the territory. The noise maps showing noise propagation can be effectively used in evaluating and controlling the noise effects. In this study, it was aimed to measure the anthropogenic noise levels &amp;#8203;&amp;#8203;resulting from the chainsaw used in tree felling and to map its noise propagation with SPreAD-GIS (System for Prediction of Acoustic Detectability) which is a GIS (Geographical Information Systems) based noise prediction software. The study was conducted in Karacabey Flooded Forest within the city of Bursa in Türkiye. The results indicated that the average noise level from the chainsaw was above the danger limit (90 dBA) that causes increased physiological reactions and headache on the workers. According to the noise propagation map, the noise exposure of the employees exceeded the warning limit (85 dBA) and the maximum noise level was 95.96 dBA during the harvesting activity. In some parts of the study area, the noise level was 45 dBA or above, causing negative effects on bird species. It can be concluded that the noise maps can be effectively used to determine noise propagation generated by a chainsaw and evaluate the noise effects on the operators and as well as on the bird species in the perimeter.

Targeted ablation of residual pulmonary vein potentials in atrial fibrillation ablation through ultra-high-density mapping: Insights from the CHARISMA registry.

Low-voltage activity beyond pulmonary veins (PVs) may contribute to the failure of ablation of atrial fibrillation (AF) in the long term. We aimed to assess the presence of gaps (PVG) and residual potential (residual antral potential [RAP]) within the antral scar by means of an ultra-high-density mapping (UHDM) system. We studied consecutive patients from the CHARISMA registry who were undergoing AF ablation and had complete characterization of residual PV antral activity. The Lumipoint™ (Boston Scientific) map-analysis tool was used sequentially on each PV component. The ablation endpoint was PV isolation (PVI) and electrical quiescence in the antral region. Fifty-eight cases of AF ablation were analyzed. A total of 86 PVGs in 34 (58.6%) patients and 44 RAPs in 34 patients (58.6%) were found. In 16 (27.6%) cases, we found at least one RAP in patients with complete absence of PV conduction. RAPs showed a lower mean voltage than PVG (0.3 ± 0.2 mV vs. 0.7 ± 0.5 mV, p < .0001), whereas the mean number of electrogram peaks was higher (8.4 ± 1.4 vs. 3.2 ± 1.5, p < .0001). The percentage of patients in whom RAPs were detected through Lumipoint™ was higher than through propagation map analysis (58.6% vs. 36.2%, p = .025). Acute procedural success was 100%, with all PVs successfully isolated and RAPs completely abolished in all study patients. During a mean follow-up of 453 ± 133 days, 6 patients (10.3%) suffered an AF/AT recurrence. Local vulnerabilities in antral lesion sets were easily discernible by means of the UHDM system in both de novo and redo patients when no PV conduction was present.

Long-term outcomes of non-contact multi-electrode balloon catheter mapping-guided ablation of ventricular arrhythmias originating from the outflow tract

IntroductionThe outflow tract (OT) regions of the ventricles are a common location of origin for idiopathic ventricular arrhythmias (VA). Non-contact mapping (NCM) with a multi-electrode balloon catheter Ensite-Array enables three-dimensional reconstruction of the geometry of the cardiac chambers and accurate mapping of the propagation map, based on a single beat analysis, facilitating the ablation and contributing procedure success. ObjectiveAssessment of the feasibility and long-term outcomes following NCM-guided OT VA ablation. MethodsSingle center retrospective analysis of patients admitted for symptomatic OT VA ablation. Demographic and clinical characteristics of patients, procedure data and long-term outcomes were assessed. ResultsFifty-eight patients (79.3% female, age 43.9±17.6 years) were considered, 89.7% without structural heart disease. In 85.7% of the cases left ventricle ejection fraction (LVEF) was preserved (LVEF≥50%), 8.6% had mild systolic dysfunction (LVEF 40%-49%) and 5.7% had moderate systolic dysfunction (LVEF 30%-39%). Twenty-four-hour Holter recording documented sustained VA episodes in 12.1% of the patients, non-sustained VA in 31.0%, and >10 000 premature ventricular complex (PVC)/24 h in 56.9%, with an ECG suggesting right ventricular OT origin in 84.5%. There was total elimination of PVC in 87.9% cases and a significant reduction in 3.4%. During a mean follow-up of 5.5 years, 87.9% patients remained asymptomatic without medication, 12.1% underwent re-ablation due to symptomatic PVC recurrence, and two cases underwent a third successful intervention. ConclusionNon-contact mapping-guided multi-electrode balloon catheter VA ablation is a highly effective and safe procedure, with a low rate of long-term recurrence.

Short-time ventricular tachycardia ablation for cardiac sarcoidosis using coherent map.

A 69‐year‐old woman with isolated cardiac sarcoidosis was hospitalized for frequent appropriate implantable converter defibrillator therapies for ventricular tachycardia (VT) despite of favorably controlled condition with oral prednisolone. The patient underwent urgent catheter ablation with CARTO 3D mapping system. Although the voltage map, activation map, and propagation map during VT could not visualize the tachycardia circuit, the coherent map clarified entrance and exit sites of the tachycardia circuit with slow or nonconducting (SNO) zones, which seemed like a figure‐of‐eight circuit. Considering the risk of VT termination or acceleration to rapid unstable VT, neither entrainment nor pacing studies were performed. The VT was terminated near the exit site of the isthmus where tiny pre‐systolic potential was detected. Any diastolic potentials could not be detected. This meant that the critical isthmus might be located at the epicardium or deep incite of the left‐ventricular myocardium where the coherent map showed as SNO zones. We should recognize coherent map as artificial that may represent VT circuit as if complete endocardial reentry even if not. The procedural time from mapping to termination of VT was only 22 minutes. The patient has been free from any cardiovascular events after the procedure. Coherent map might be feasible for revealing the critical isthmus of hemodynamically stable VTs without using electrophysiological techniques, including entrainment, pacing study, and voltage map during own beats, and would enable us to achieve successful VT ablation in a short time.

Evaluation of liver fibrosis in chronic hepatitis B patients with 2D shear wave elastography with propagation map guidance: a single-centre study

BackgroundThe aims of this study were to evaluate liver fibrosis with two-dimensional (2D) shear wave elastography (SWE) in patients with chronic hepatitis B (CHB), to compare 2D-SWE with histopathology and to determine the change in liver stiffness values after antiviral therapy.Material and methodsA total of 253 patients with CHB were included in this prospective study. 2D-SWE with propagation map guidance to measure liver stiffness, fibrosis-4 index (FIB-4) and aspartate aminotransferase to platelet ratio index (APRI) scoring and additional liver biopsy were performed in patients with CHB. Liver stiffness was measured again at 24 and 48 weeks in all patients. The Spearman rank correlation test was used to analyse the correlation between variables, and receiver operating curve analysis was used to evaluate the diagnostic performance in terms of fibrosis.ResultsLiver stiffness measurements made with 2D-SWE demonstrated a significant positive correlation with the fibrosis stage and FIB-4 score (rs = 0.774 and 0.337, respectively, p < 0.001 for both). The area under the curve value for kPa for the prediction of significant fibrosis was 0.956 (95% CIs) (0.920–0.991), and the optimal cut-off value was 8.2 kPa (sensitivity: 92.7% and specificity: 78.9%); these values were 0.978 (95% CIs, 0.945–1.000) and 10.1 kPa (sensitivity: 92.9% and specificity: 96.4%) for the prediction of severe fibrosis. After antiviral treatment, a decrease in liver stiffness values measured by 2D-SWE was detected (mean kPa values at 0 and 48 weeks; 9.24 and 7.36, respectively, p < 0.001).ConclusionIn conclusion, the measurement of liver stiffness with 2D-SWE has high diagnostic performance in the determination of hepatic fibrosis and can be used to evaluate the response to treatment in patients receiving antiviral therapy.

GMNN2CD: identification of circRNA-disease associations based on variational inference and graph Markov neural networks.

With the analysis of the characteristic and function of circular RNAs (circRNAs), people have realized that they play a critical role in the diseases. Exploring the relationship between circRNAs and diseases is of far-reaching significance for searching the etiopathogenesis and treatment of diseases. Nevertheless, it is inefficient to learn new associations only through biotechnology. Consequently, we present a computational method, GMNN2CD, which employs a graph Markov neural network (GMNN) algorithm to predict unknown circRNA-disease associations. First, used verified associations, we calculate semantic similarity and Gaussian interactive profile kernel similarity (GIPs) of the disease and the GIPs of circRNA and then merge them to form a unified descriptor. After that, GMNN2CD uses a fusion feature variational map autoencoder to learn deep features and uses a label propagation map autoencoder to propagate tags based on known associations. Based on variational inference, GMNN alternate training enhances the ability of GMNN2CD to obtain high-efficiency high-dimensional features from low-dimensional representations. Finally, 5-fold cross-validation of five benchmark datasets shows that GMNN2CD is superior to the state-of-the-art methods. Furthermore, case studies have shown that GMNN2CD can detect potential associations. The source code and data are available at https://github.com/nmt315320/GMNN2CD.git.

Simulation of forest fire spread based on artificial intelligence

This article aims to provide a more practical forest fire spread model for predicting and managing forest fires in Heilongjiang Province, China. Heilongjiang is dominated by spatially heterogeneous combustible forests with undulating terrain and steep slopes. In this article, an artificial neural network framework is used to generate an accurate flame propagation map. Considering inherent fire propagation uncertainties, a fire propagation model containing multidimensional physical and environmental variables is established. Based on fire propagation predictions, the physical fire propagation method is also effectively understood. Additionally, the artificial neural network model can analyse spatial time series patterns and is not a traditional fire spread model. Moreover, this study established a forest fire spread prediction model combining Heilongjiang's cellular automata and Wang Zhengfei's model for comparison with the artificial neural network model. After repeated training and testing, the forest fire prediction results based on the artificial neural network, were found to have average accuracy, sensitivity, and F-measure values of 85.02%, 95.26%, and 89.85%, respectively. The proposed model is suitable for prediction of fire spread beyond large forest fires (more than 1 ha and less than 100 ha of affected forest). Therefore, the model facilitates a better understanding of fire cover propagation behaviours and quickly generates fire peak profiles. The proposed model can enable forest managers and firefighting agencies to plan better firefighting operations and improved firefighting strategy effectiveness.

Propagation Map Reconstruction via Interpolation Assisted Matrix Completion

Constructing a propagation map from a set of scattered measurements finds important applications in many areas, such as localization, spectrum monitoring and management. Classical interpolation-type methods have poor performance in regions with very sparse measurements. Recent advance in matrix completion has the potential to reconstruct a propagation map from sparse measurements, but the spatial resolution is limited. This paper proposes to integrate interpolation with matrix completion to exploit both the spatial correlation and the potential low rank structure of the propagation map. The proposed method first enriches matrix observations using interpolation, and develops the statistics of the interpolation error based on a local polynomial regression model. Then, two uncertainty-aware matrix completion algorithms are developed to exploit the interpolation error statistics. It is numerically demonstrated that the proposed method outperforms Kriging and other state-of-the-art schemes, and reduces the mean squared error (MSE) of propagation map reconstruction by 10%-50% for a medium to large number of measurements.

Demonstration of Double-Wave-Like Reentry Using Activation and Propagation Map in a Patient with Atrial Flutter and Previous Atrial Septal Defect Surgery

Three-dimensional electroanatomic maps have revolutionized the management of complex arrhythmia. By providing a visual display of various arrhythmia mechanisms these maps have not only helped with the mechanism of the tachycardia but also allowed for precise localization of the critical isthmus. Herein, we present an interesting propagation map of a 55-year-old female with scar-related right-sided atrial flutter. The propagation map helped in localizing the critical isthmus and subsequent successful ablation.

Ultra-high resolution mapping of reverse typical atrial flutter: electrophysiological properties of a right atrial posterior wall and interatrial septum activation pattern.

We aimed to elucidate the right atrial posterior wall (RAPW) and interatrial septum (IAS) conduction pattern during reverse typical atrial flutter (clockwise AFL: CW-AFL). This study included 30 patients who underwent catheter ablation of CW-AFL (n = 11) and counter-clockwise AFL (CCW-AFL; n = 19) using an ultra-high resolution mapping system. RAPW transverse conduction block was evaluated by the conduction pattern on propagation maps and double potentials separated by an isoelectric line. The degree of blockade was evaluated by the %blockade, which was calculated by the length of the blocked area divided by the RAPW length. IAS activation patterns were also investigated dependent on the propagation map. The average %blockade of the RAPW was significantly smaller in patients with CW-AFL than those with CCW-AFL (25 [3-74]% vs. 67 [57-75]%, p < 0.05). CW-AFL patients exhibited 3 different RAPW conduction patterns: (1) a complete blockade pattern (3 patients), (2) moderate (> 25% blockade) blockade pattern (2 patients), and (3) little (< 25% blockade) blockade pattern (6 patients). In contrast, the little blockade pattern was not observed in CCW-AFL patients. Of 11 CW-AFL patients, 4, including all patients with an RAPW complete blockade pattern, had an IAS activation from the wavefront from the anterior tricuspid annulus (TA), and 6 had an IAS activation from the wavefronts from both the anterior TA and RAPW. One patient had IAS activation dominantly from the wavefront from the RAPW. RAPW transverse conduction blockade during CW-AFL was less frequent than during CCW-AFL, which possibly caused various IAS activation patterns.