The three-dimensional（3D） visualization of the functional bundles in the peripheral nerve provides direct and detailed intraneural spatial information. It is useful for selecting suitable surgical methods to repair ...The three-dimensional（3D） visualization of the functional bundles in the peripheral nerve provides direct and detailed intraneural spatial information. It is useful for selecting suitable surgical methods to repair nerve defects and in optimizing the construction of tissue-engineered nerve grafts. However, there remain major technical hurdles in obtaining, registering and interpreting 2D images, as well as in establishing 3D models. Moreover, the 3D models are plagued by poor accuracy and lack of detail and cannot completely reflect the stereoscopic microstructure inside the nerve. To explore and help resolve these key technical problems of 3D reconstruction, in the present study, we designed a novel method based on re-imaging techniques and computer image layer processing technology. A 20-cm ulnar nerve segment from the upper arm of a fresh adult cadaver was used for acetylcholinesterase（ACh E） staining. Then, 2D panoramic images were obtained before and after ACh E staining under the stereomicroscope. Using layer processing techniques in Photoshop, a space transformation method was used to fulfill automatic registration. The contours were outlined, and the 3D rendering of functional fascicular groups in the long-segment ulnar nerve was performed with Amira 4.1 software. The re-imaging technique based on layer processing in Photoshop produced an image that was detailed and accurate. The merging of images was accurate, and the whole procedure was simple and fast. The least square support vector machine was accurate, with an error rate of only 8.25%. The 3D reconstruction directly revealed changes in the fusion of different nerve functional fascicular groups. In conclusion. The technique is fast with satisfactory visual reconstruction.展开更多
Background Verapamil-sensitive, idiopathic left ventricular tachycardia （ILVT） with right bundle branch block configuration and left-axis deviation is known to be due to re-entry mechanism but the exact nature of re...Background Verapamil-sensitive, idiopathic left ventricular tachycardia （ILVT） with right bundle branch block configuration and left-axis deviation is known to be due to re-entry mechanism but the exact nature of reentrant circuit in ILVT is not fully elucidated. Radiofrequency （RF） ablation was applied during ventricular tachycardia （VT） and termination of the VT or abolishing the inducibility of the tachycardia was used as an endpoint for successful RF. In this study, the left posterior fascicular block in surface electrocardiogram （ECG） was used as a new endpoint of ablation to cure ILVT. Methods Electrophysiological studies and radiofrequency ablation were performed in 39 consecutive patients [30 men, 9 women; age ranging from 10 to 64 years, mean （29± 16） years] with verapamil-sensitive ILVT and structurally normal hearts. VT could be terminated by the intravenous adininistration of verapamil in all patients. The target site was the midseptum of LV where the earliest Purkinje potentials were recorded during VT. RF current was applied to the target site with or without late diastolic potential （LDP） during sinus rhythm in 37 patients and during VT in 2 patients to meet the ablation endpoint： the left posterior fascicuiar block in the surface ECG. Results Thirty-seven patients with ILVT had been treated by RF ablation during sinus rhythm and two had been treated during VT. All of them met the endpoint of the left posterior fascicuiar block. Thirty-eight cases were symptom-free without medications during the follow-up period （range from 3 to 95 months, median 17 months）. One patient developed a clinical recurrence and the left posterior fascicuiar block in surface ECG disappeared. The patient received another treatment. The endpoint was met and the procedure was successful. Conclusions The left posterior fascicuiar block in surface ECG used as an endpoint of RF ablation to treat ILVT is effective. It is important especially in those patients whose VT can not be induced or the inducible condition is unstable. The effective endpoint implied that the left posterior fascicle might be a critical part of the re-entrant circuit.展开更多
Left anterior fascicular block（LAFB） is a heart disease identifiable from an abnormal electrocardiogram（ECG）. It has been reported that LAFB is associated with an increased risk of heart failure. Non-specific intr...Left anterior fascicular block（LAFB） is a heart disease identifiable from an abnormal electrocardiogram（ECG）. It has been reported that LAFB is associated with an increased risk of heart failure. Non-specific intraventricular conduction delay due to the lesions of the conduction bundles and slow cell to cell conduction has also been considered as another cause of heart failure. Since the location and mechanism of conduction delay have notable variability between individual patients, we hypothesized that the impaired conduction in the ventricular myocardium may lead to abnormal ECGs similar to LAFB ECG patterns. To test this hypothesis, based on a computer model with a three dimensional whole-heart anatomical structure, we simulated the cardiac exciting sequence map and 12-lead ECG caused by the block in the left anterior fascicle and by the slowed conduction velocity in the ventricular myocardium. The simulation results showed that the typical LAFB ECG patterns can also be observed from cases with slowed conduction velocity in the ventricular myocardium. The main differences were the duration of QRS and wave amplitude. In conclusion, our simulations provide a promising starting point to further investigate the underlying mechanism of heart failure with LAFB, which would provide a potential reference for LAFB diagnosis.展开更多
The most common methods for three-dimensional reconstruction of peripheral nerve fascicles include histological and radiology techniques. Histological techniques have many drawbacks including an enormous manual worklo...The most common methods for three-dimensional reconstruction of peripheral nerve fascicles include histological and radiology techniques. Histological techniques have many drawbacks including an enormous manual workload and poor image registration. Micro-magnetic resonance imaging（Micro-MRI）, an emerging radiology technique, has been used to report results in the brain, liver and tumor tissues. However, micro-MRI usage for obtaining intraneural structures has not been reported. The aim of this study was to present a new imaging method for three-dimensional reconstruction of peripheral nerve fascicles by ~1T micro-MRI. Freshly harvested sciatic nerve samples from an amputated limb were divided into four groups. Two different scanning conditions（Mannerist Solution/GD-DTPA contrast agent, distilled water） were selected, and both T1 and T2 phases programmed for each scanning condition. Three clinical surgeons evaluated the quality of the images via a standardized scale. Moreover, to analyze deformation of the two-dimensional image, the nerve diameter and total area of the micro-MRI images were compared after hematoxylin-eosin staining. The results show that rapid micro-MRI imaging method can be used for three-dimensional reconstruction of the fascicle structure. Nerve sample immersed in contrast agent（Mannerist Solution/GD-DTPA） and scanned in the T1 phase was the best. Moreover, the nerve sample was scanned freshly and can be recycled for other procedures. MRI images show better stability and smaller deformation compared with histological images. In conclusion, micro-MRI provides a feasible and rapid method for three-dimensional reconstruction of peripheral nerve fascicles, which can clearly show the internal structure of the peripheral nerve.展开更多
基金supported by the National Natural Science Foundation of China,No.30571913a grant from the Science and Technology Project of Guangdong Province of China,No.2013B010404019+1 种基金the Natural Science Foundation of Guangdong Province of China,No.9151008901000006the Medical Scientific Research Foundation of Guangdong Province of China,No.A2009173
文摘The three-dimensional（3D） visualization of the functional bundles in the peripheral nerve provides direct and detailed intraneural spatial information. It is useful for selecting suitable surgical methods to repair nerve defects and in optimizing the construction of tissue-engineered nerve grafts. However, there remain major technical hurdles in obtaining, registering and interpreting 2D images, as well as in establishing 3D models. Moreover, the 3D models are plagued by poor accuracy and lack of detail and cannot completely reflect the stereoscopic microstructure inside the nerve. To explore and help resolve these key technical problems of 3D reconstruction, in the present study, we designed a novel method based on re-imaging techniques and computer image layer processing technology. A 20-cm ulnar nerve segment from the upper arm of a fresh adult cadaver was used for acetylcholinesterase（ACh E） staining. Then, 2D panoramic images were obtained before and after ACh E staining under the stereomicroscope. Using layer processing techniques in Photoshop, a space transformation method was used to fulfill automatic registration. The contours were outlined, and the 3D rendering of functional fascicular groups in the long-segment ulnar nerve was performed with Amira 4.1 software. The re-imaging technique based on layer processing in Photoshop produced an image that was detailed and accurate. The merging of images was accurate, and the whole procedure was simple and fast. The least square support vector machine was accurate, with an error rate of only 8.25%. The 3D reconstruction directly revealed changes in the fusion of different nerve functional fascicular groups. In conclusion. The technique is fast with satisfactory visual reconstruction.
文摘Background Verapamil-sensitive, idiopathic left ventricular tachycardia （ILVT） with right bundle branch block configuration and left-axis deviation is known to be due to re-entry mechanism but the exact nature of reentrant circuit in ILVT is not fully elucidated. Radiofrequency （RF） ablation was applied during ventricular tachycardia （VT） and termination of the VT or abolishing the inducibility of the tachycardia was used as an endpoint for successful RF. In this study, the left posterior fascicular block in surface electrocardiogram （ECG） was used as a new endpoint of ablation to cure ILVT. Methods Electrophysiological studies and radiofrequency ablation were performed in 39 consecutive patients [30 men, 9 women; age ranging from 10 to 64 years, mean （29± 16） years] with verapamil-sensitive ILVT and structurally normal hearts. VT could be terminated by the intravenous adininistration of verapamil in all patients. The target site was the midseptum of LV where the earliest Purkinje potentials were recorded during VT. RF current was applied to the target site with or without late diastolic potential （LDP） during sinus rhythm in 37 patients and during VT in 2 patients to meet the ablation endpoint： the left posterior fascicuiar block in the surface ECG. Results Thirty-seven patients with ILVT had been treated by RF ablation during sinus rhythm and two had been treated during VT. All of them met the endpoint of the left posterior fascicuiar block. Thirty-eight cases were symptom-free without medications during the follow-up period （range from 3 to 95 months, median 17 months）. One patient developed a clinical recurrence and the left posterior fascicuiar block in surface ECG disappeared. The patient received another treatment. The endpoint was met and the procedure was successful. Conclusions The left posterior fascicuiar block in surface ECG used as an endpoint of RF ablation to treat ILVT is effective. It is important especially in those patients whose VT can not be induced or the inducible condition is unstable. The effective endpoint implied that the left posterior fascicle might be a critical part of the re-entrant circuit.
基金Project supported by the National Natural Science Foundation of China(Nos.61527811 and 61701435)
文摘Left anterior fascicular block（LAFB） is a heart disease identifiable from an abnormal electrocardiogram（ECG）. It has been reported that LAFB is associated with an increased risk of heart failure. Non-specific intraventricular conduction delay due to the lesions of the conduction bundles and slow cell to cell conduction has also been considered as another cause of heart failure. Since the location and mechanism of conduction delay have notable variability between individual patients, we hypothesized that the impaired conduction in the ventricular myocardium may lead to abnormal ECGs similar to LAFB ECG patterns. To test this hypothesis, based on a computer model with a three dimensional whole-heart anatomical structure, we simulated the cardiac exciting sequence map and 12-lead ECG caused by the block in the left anterior fascicle and by the slowed conduction velocity in the ventricular myocardium. The simulation results showed that the typical LAFB ECG patterns can also be observed from cases with slowed conduction velocity in the ventricular myocardium. The main differences were the duration of QRS and wave amplitude. In conclusion, our simulations provide a promising starting point to further investigate the underlying mechanism of heart failure with LAFB, which would provide a potential reference for LAFB diagnosis.
基金supported by grants from the National Key Research and Development Plan of China,No.31670986(to QTZ)the Science and Technology Project of Guangdong Province of China,No.2014B020227001,2017A050501017(to QTZ)the Science and Technology Project of Guangzhou of China,No.201807010082(to QTZ),201704030041(to JQ)
文摘The most common methods for three-dimensional reconstruction of peripheral nerve fascicles include histological and radiology techniques. Histological techniques have many drawbacks including an enormous manual workload and poor image registration. Micro-magnetic resonance imaging（Micro-MRI）, an emerging radiology technique, has been used to report results in the brain, liver and tumor tissues. However, micro-MRI usage for obtaining intraneural structures has not been reported. The aim of this study was to present a new imaging method for three-dimensional reconstruction of peripheral nerve fascicles by ~1T micro-MRI. Freshly harvested sciatic nerve samples from an amputated limb were divided into four groups. Two different scanning conditions（Mannerist Solution/GD-DTPA contrast agent, distilled water） were selected, and both T1 and T2 phases programmed for each scanning condition. Three clinical surgeons evaluated the quality of the images via a standardized scale. Moreover, to analyze deformation of the two-dimensional image, the nerve diameter and total area of the micro-MRI images were compared after hematoxylin-eosin staining. The results show that rapid micro-MRI imaging method can be used for three-dimensional reconstruction of the fascicle structure. Nerve sample immersed in contrast agent（Mannerist Solution/GD-DTPA） and scanned in the T1 phase was the best. Moreover, the nerve sample was scanned freshly and can be recycled for other procedures. MRI images show better stability and smaller deformation compared with histological images. In conclusion, micro-MRI provides a feasible and rapid method for three-dimensional reconstruction of peripheral nerve fascicles, which can clearly show the internal structure of the peripheral nerve.
