Lorenz plot (LP) method which gives a global view of long-time electrocardiogram signals, is an efficient simple visualization tool to analyze cardiac arrhythmias, and the morphologies and positions of the extracted attractors may reveal the underlying mechanisms of the onset and termination of arrhythmias. But automatic diagnosis is still impossible because it is lack of the method of extracting attractors by now. We presented here a methodology of attractor extraction and recognition based upon homogeneously statistical properties of the location parameters of scatter points in three dimensional LP (3DLP), which was constructed by three successive RR intervals as X, Y and Z axis in Cartesian coordinate system. Validation experiments were tested in a group of RR-interval time series and tags data with frequent unifocal premature complexes exported from a 24-hour Holter system. The results showed that this method had excellent effective not only on extraction of attractors, but also on automatic recognition of attractors by the location parameters such as the azimuth of the points peak frequency (APF) of eccentric attractors once stereographic projection of 3DLP along the space diagonal. Besides, APF was still a powerful index of differential diagnosis of atrial and ventricular extrasystole. Additional experiments proved that this method was also available on several other arrhythmias. Moreover, there were extremely relevant relationships between 3DLP and two dimensional LPs which indicate any conventional achievement of LPs could be implanted into 3DLP. It would have a broad application prospect to integrate this method into conventional long-time electrocardiogram monitoring and analysis system.
Objective To investigate the validity of improving the femur’s mechanical characteristics by implanting calcium phosphate ceramic screws after removing dynamic hip screw (DHS). Methods The three dimensional finite element model of the femur was built based on the CT scanning of a normal male volunteer. Then the models of the femur with and without DHS were established. According to calcium phosphate ceramic screws with porosity and apparent elastic modulus, 80% and 0.1 GPa were set as group A, 50% and 1.0 GPa as group B, and 30% and 1.5 GPa as group C. Von Mises stress distribution and maximum stress were recorded when the joint was maximally loaded in a gait cycle. Results The Von Mises in normal femoral shaft was uniform; no phenomena of stress concentration was observed and the maximum stress located at the joint load-bearing site of the proximal femur. The stress concentration was observed in the femur without DHS, and the maximum stress located at the distal femur around the screw hole. By comparing several different calcium phosphate ceramic screws, the stress distribution of group B was similar to normal femur model, and the maximum stress located at the joint load-bearing site. The other screws of groups A and C showed varying degrees of stress concentration. Conclusion Implanting calcium phosphate ceramic screw can improve the mechanical characteristics of the femur after removing dynamic hip screw, and the calcium phosphate ceramic screw with 50% porosity and 1.0 GPa apparent elastic modulus is suitable for implanting.
As an interface between external electronic devices and internal neural nuclei, microelectrodes play an important role in many fields, such as animal robots, deep brain stimulation and neural prostheses. Aiming at the problem of high price and complicated fabrication process of microelectrode, a microelectrode twisting machine based on open source electronic prototyping platform (Arduino) and three-dimensional printing technology was proposed, and its microelectrode fabrication performance and neural stimulation performance were verified. The results show that during the fabrication of microelectrodes, the number of positive twisting turns of the electrode wire should generally be set to about 1.8 times of its length, and the number of reverse twisting rings is independent of the length, generally about 5. Moreover, compared with the traditional instrument, the device is not only inexpensive and simple to manufacture, but also has good expandability. It has a positive significance for both the personalization and popularization of microelectrode fabrication and the reduction of experimental cost.
摘要:目的:探討三維電解剖標測系統(CARTO)指導下進行房性心動過速射頻消融的方法及效果。方法:對40例房性心動過速患者應用CARTO標測心房, 構建三維電解剖圖,分析房性心動過速的電生理機制。局灶性房速消融最早激動點,大折返性房速消融折返環的關鍵性峽部。選擇利用常規方法行消融的28 例患者作為對照組。比較兩組消融的成功率、X線曝光時間。結果:38例患者CARTO三維標測系統標測提示為局灶性房性心動過速, 最早激動點位于右心房35例,其中冠狀靜脈竇口8例(20%)、間隔部10例(25%)、側壁8例(20%)、上腔靜脈口附近4例(10%)、后壁4例(10 %),1例患者(2.5%)有3種類型房速(分別為間隔部、上腔靜脈口的局灶房速和三尖瓣峽部依賴的大折返房速)。位于左心房的局灶房速3例,分別位于右上肺靜脈口(2.5%)、左上肺靜脈口(2.5%)及左心耳(2.5%)。2例患者為大折返房速(5%),1例為三尖瓣峽部依賴性,1例為圍繞界嵴的大折返房速。均消融成功(100%),隨訪4~16個月,均無復發。常規消融組成功率為89.3%(Plt;0.05)。CARTO組X線曝光時間比常規組明顯縮短,分別為(13.8±5.5 ) min 和( 30.4±12.9 ) min,差異有統計學意義（Plt;0.05）。結論:應用CARTO標測房性心動過速, 對分析房性心動過速的機制準確快速, 能有效指導射頻消融。Abstract: Objective: To evaluate the methods and effects of radiofrequency ablation of atrial tachycardia guided by CARTO. Methods: The atria of 40 cases were mapped by three dimensional electroanatomic mapping system. In order to analyse the mechanism of atrial tachycardia and perform the ablation of the earliest excited point in focal atrial tachycardia and isthmus in macroreentry atrial tachycardia. 28 cases ablated by conventional procedure were selected as controlled group. The success rate and fluoroscopic time were compared between the two groups. Results: Focal atrial tachycardia was seen in 38 patients. The sites of origin from right atrium were at the coronary sinus ostium in 8 cases (20%), septal in 10 cases (25%), lateral wall in 8 cases (20%), superior vena cava ostium in 4 cases (10%), posterior wall in 4 cases (10%). One case had 3 types of atrial tachycardia (2.5%). The sites of origin from left atrium were at right pulmonary vein ostium in 1 case (2.5%), left pulmonary vein ostium in 1 case (2.5%), left auricular appendage in 1 case (2.5%). 2 cases were macroreentry atrial tachycardia (5%). Ablation was performed successfully (100%) without any complication. No recurrence was found during a followup of 416 months. Success rate in conventional group was 89.3%(Plt;0.05)。Comparing the CARTO group and conventional group, the fluoroscopic time was shorter, ( 13.8±5.5 ) min vs ( 30.4±12.9 ) min （Plt;0.05).Conclusion: The mechanism of atrial tachycardia can be evaluated quickly and accurately. Ablation can be performed safely and effectively guided by CARTO.
ObjectiveTo analyze the difference of location identification of pulmonary nodules in two dimensional (2D) and three dimensional (3D) images, and to discuss the identification methods and clinical significance of pulmonary nodules location in 3D space.MethodsThe clinical data of 105 patients undergoing sublobectomy in the Department of Thoracic Surgery, the First Affiliated Hospital with Nanjing Medical University from December 2018 to December 2019 were analyzed retrospectively. There were 28 males and 77 females, with an average age of 57.21±13.19 years. The nodule location was determined by traditional 2D method and 3D depth ratio method respectively, and the differences were compared.ResultsA total of 30 nodules had different position identification between the two methods, among which 25 nodules in the inner or middle zone of 2D image were located in the peripheral region of 3D image. The overall differences between the two methods were statistically significant (P<0.05). The diagnostic consistency rates of two methods were 66.67% in the right upper lung, 83.33% in the right middle lung, 73.68% in the right lower lung, 75.76% in the left upper lung, and 64.71% in the left lower lung. In each lung lobe, the difference between the two methods in the right upper lung (P=0.014) and the left upper lung (P=0.019) was statistically significant, while in the right middle lung (P=1.000), right lower lung (P=0.460) and left lower lung (P=0.162) were not statistically significant.ConclusionThe 3D position definition of lung nodules based on depth ratio is more accurate than the traditional 2D definition, which is helpful for preoperative planning of sublobectomy.
Three dimensional (3D) bioprinting is a new biological tissue engineering technology in recent years. The development of 3D bioprinting is conducive to solving the current problems of clinical tissue and organ repairing. This article provides a review about the clinical and research status of 3D bioprinting and urinary system reconstruction. Furthermore, the feasibility and clinical value of 3D bioprinting in urinary system reconstruction will be also discussed.
ObjectiveTo explore the value of artificial intelligence (AI) diagnostic imaging system and three dimensional computed tomographic bronchoangiography (3D-CTBA) surgical planning system in the management of multiple primary lung cancer (MPLC).MethodsThe clinical data of 53 patients with MPLC treated surgically in our hospital from January 2018 to August 2020 were retrospectively analyzed, including 16 males and 37 females, with a median age of 60 (39-75) years. The patients' preoperative CT was analyzed by AI and manually, and the data of patients who underwent 3D-CTBA were compiled to evaluate the value of AI and 3D-CTBA in the diagnosis and treatment of MPLC, respectively.Results The sensitivity of AI screening for MPLC was 84.91%. The sensitivity (91.90% vs. 83.78%) and accuracy (85.60% vs. 84.00%) of AI diagnosis of high-risk MPLC infiltrative lesions were better than those of manual diagnosis. 3D-CTBA was used for planning the surgery in 12 patients, and the intraoperative situation was generally consistent with the reconstructed results.ConclusionAI is of high value in identifying infiltrative lesions of MPLC. 3D-CTBA reconstruction of anatomical structures is accurate and can guide preoperative planning.
Objective To compare surgical results between real-time three dimensional echocardiography（RT-3DE） guided closure of atrial septal defect （ASD） through a right minithoracotomy and traditional surgical repair under cardiopulmonary bypass （CPB）. Methods Sixty-four patients with secundum ASD received surgical repair in the First People’s Hospital of Honghe Autonomous Prefecture from April 2009 to April 2012. According to different surgical approach, all the patients were divided into group A and B. In group A, 35 patients underwent traditional ASD repair under CPB including 20males and 15 females with their age of 12-56 （16.4±4.0） years. In group B, 29 patients received real-time RT-3DE guidedASD closure through a right minithoracotomy without CPB, including 20 males and 15 females with their age of 15-50 （18.5±0.2） years. Operation time，postoperative mechanical ventilation time，hospital stay，chest drainage，mortality，morbidity and follow-up outcomes were compared between the 2 groups. Results Operation time （110.47±35.90 minutesvs. 159.32±20.60 minutes），postoperative mechanical ventilation time （10.40±22.30 hours vs. 16.40±12.20 hours），chestdrainage （106.71±85.20 ml vs. 146.70±75.63 ml）and postoperative hospital stay （4.0±1.0 days vs. 7.0±1.0 days）ofgroup B were significantly shorter or less than those of group A. In group A, 1 patient died postoperatively and 7 patientshad postoperative complications. In group B, there was no in-hospital mortality and 3 patients had postoperative complications.Postoperative morbidity of group A was significantly higher than that of group B （20.0% vs. 10.3%，P＜0.05） . ConclusionFor ASD patients with definite surgical indications，RT-3DE guided ASD closure through a right minithoracotomy has more advantages over traditional surgical repair under CBP.
Objective To introduce a novel classification method for pectus excavatum. Methods A retrospective review of 569 operative patients with pectus excavatum between January 2015 and September 2017 in our hospital was performed. The malformations were described and classified from three dimensions: symmetry (abbreviated as S), depth (abbreviated as D) and position (abbreviated as P). The final integral was calculated according to the deformity index, so that the severity of the deformity could be evaluated. All patients underwent Nuss or modified Nuss surgery. Results All pectus excavatum deformities were classified into 24 types. The most common type was S1D2P1, accounting for 27.2% of the total patients followed by S1D2P2, S1D1P2 and S2D2P2, accounting for 12.0%, 11.6% and 11.4% of all patients respectively. S1D3P3, S1D3P4 and S2D3P3 were not found in our patients. According to the integral, 321 patients were mild, 23 severe, and the rest were moderate. The appearance of all patients improved after the operation. Among them, 405 patients were implanted with a plate, 159 with two plates and 5 with three plates. The length of hospital stay was 5-12 d, with an average of 7.3±1.5 d. Conclusion This classification method is a more comprehensive classification, but its scientific and practical characteristics need to be further confirmed.
More and more medical devices can capture different features of human body and form three dimensional (3D) images. In clinical applications, usually it is required to fuse multiple source images containing different and crucial information into one for the purpose of assisting medical treatment. However, traditional image fusion methods are normally designed for two dimensional (2D) images and will lead to loss of the third dimensional information if directly applied to 3D data. Therefore, a novel 3D magnetic image fusion method was proposed based on the combination of newly invented beyond wavelet transform, called 3D band limited shearlet transformand (BLST), and four groups of traditional fusion rules. The proposed method was then compared with the 2D and 3D wavelet and dual-tree complex wavelet transform fusion methods through 4 groups of human brain T2* and quantitative susceptibility mapping (QSM) images. The experiments indicated that the performance of the method based on 3D transform was generally superior to the existing methods based on 2D transform. Taking advantage of direction representation, shearlet transform could effectively improve the performance of conventional fusion method based on 3D transform. It is well concluded, therefore, that the proposed method is the best among the methods based on 2D and 3D transforms.