Automatic mandibular canal detection using a deep convolutional neural network

The practicability of deep learning techniques has been demonstrated by their successful implementation in varied fields, including diagnostic imaging for clinicians. In accordance with the increasing demands in the healthcare industry, techniques for automatic prediction and detection are being widely researched. Particularly in dentistry, for various reasons, automated mandibular canal detection has become highly desirable. The positioning of the inferior alveolar nerve (IAN), which is one of the major structures in the mandible, is crucial to prevent nerve injury during surgical procedures. However, automatic segmentation using Cone beam computed tomography (CBCT) poses certain difficulties, such as the complex appearance of the human skull, limited number of datasets, unclear edges, and noisy images. Using work-in-progress automation software, experiments were conducted with models based on 2D SegNet, 2D and 3D U-Nets as preliminary research for a dental segmentation automation tool. The 2D U-Net with adjacent images demonstrates higher global accuracy of 0.82 than naïve U-Net variants. The 2D SegNet showed the second highest global accuracy of 0.96, and the 3D U-Net showed the best global accuracy of 0.99. The automated canal detection system through deep learning will contribute significantly to efficient treatment planning and to reducing patients’ discomfort by a dentist. This study will be a preliminary report and an opportunity to explore the application of deep learning to other dental fields.Peer reviewe

Comparison of lateral tunnel and extracardiac conduit Fontan procedure

The purpose of this study was to compare the outcomes of lateral tunnel (LT) and extracardiac conduit (ECC) Fontan procedures at a single institution. From April 1995 to December 2006, 165 Fontan procedures were performed (67 LT, 98 ECC). Pre-, intra- and postoperative variable values were compared between two different techniques. Operative mortality was 5 (3 LT, 2 ECC). Immediate postoperative transpulmonary gradient (LT 8.5+/-ECC 2.5 vs. 6.6+/-2.4 mmHg) and central venous pressure (LT 18.3+/-3.8 vs. ECC 15.6+/-2.4 mmHg) showed significant difference (P<0.001). The LT patients had a higher incidence of sinus node dysfunction in the postoperative period (22.4% vs. ECC 11.2%; P=0.05). Mean follow-up was 74.1+/-31.5 months in LT, and 31.7+/-28.1 months in ECC patients. There was one late death. Actuarial survival at 10 years is 92% for LT, and 89% for ECC patients (P=0.796). The LT and ECC, both, showed comparable early and mid-term outcomes in operative morbidity and mortality, postoperative hemodynamics, survival. Use of ECC for modified Fontan operation reduces the risk of sinus node dysfunction and shows better outcome of immediate postoperative hemodynamics

Trends in Deceased Organ Donation and Utilization in Korea: 2000-2009

Continuous efforts have been made by the organ donation and transplantation community in Korea to increase organ donation by the deceased. The authors detailed trends of organ donation and utilization over the past 10 yr using data provided by the KONOS. The yearly number of deceased donors has grown gradually since 2003. The number and percentage of old donors (≥50 yr) and donors dying from intracranial hemorrhage has increased continuously. Therefore, the percentage of standard criteria donors (SCD) has been declining significantly, from 94% in 2000 to 79.2% in 2009. The number of organs transplanted per donor (OTPD) has also declined slightly since 2007, from 3.28 in 2007 to 2.95 in 2009. This decline may be attributable to increases in the number and percentage of extended criteria donors (ECD) and donors after cardiac death (DCD), since the OTPD was 2.25 for DCD, 2.5 for ECD, and 3.09 for SCD in 2009. In summary, the makeup of donors has changed significantly. There is an urgent need for establishment of an institutional framework including an independent organ procurement organization and for improvement for the National Transplant Act to increase deceased donor pool and to optimize management of ECD and DCD

Temperature-dependent steady and transient emission properties of InGaN/GaN multiple quantum well nanorods

We observed different temperature-dependent behaviors of steady and transient emission properties in dry-etched InGaN/GaN multiple-quantum-well (MQW) nanorods and the parent MQWs. To clarify the impacts of nanofabrication on the emission properties, time-resolved photoluminescence spectra were recorded at various temperatures with carrier density in different regimes. The confinement of carrier transport was observed to play an important role to the emission properties in nanorods, inducing different temperature-dependent photoluminescence decay rates between the nanorods and MQWs. Moreover, together with other effects, such as surface damages and partial relaxation of the strain, the confinement effect causes faster recombination of carriers in nanorods.Comment: 13 pages, 4 figure

c-Fos Expression in the Nucleus of the Solitary Tract in Response to Salt Stimulation in Rats

Salt signals in tongue are relayed to the nucleus of the solitary tract (NST). This signaling is very important to determine whether to swallow salt-related nutrition or not and suggests some implications in discrimination of salt concentration. Salt concentration-dependent electrical responses in the chorda tympani and the NST were well reported. But salt concentration-dependency and spatial distribution of c-Fos in the NST were not well established. In the present study, NaCl signaling in the NST was studied in urethane-anesthetized rats. The c-Fos immunoreactivity in the six different NST areas along the rostral-caudal axis and six subregions in each of bilateral NST were compared between applications of distilled water and different concentrations of NaCl to the tongue of experimental animals. From this study, salt stimulation with high concentration (1.0 M NaCl) induced significantly higher c-Fos expression in intermediate NST and dorsal-medial and dorsal-middle subregions of the NST compared to distilled water stimulation. The result represents the specific spatial distribution of salt taste perception in the NST

The Effect of Direct Communication between Emergency Physicians and Interventional Cardiologists on Door to Balloon Times in STEMI

We developed an institutional protocol mandating emergency physicians to contact the interventional cardiologist directly in all cases of ST-segment elevation myocardial infarction (STEMI) and hypothesized that this would reduce door-to-balloon-times (DTBT). From January 2004 to July 2006, 208 patients with STEMI were treated with primary percutaneous coronary intervention (PCI). A total of 144 patients were treated before implementing the new protocol ("before") and 64 patients were treated after the implementation ("after"). The DTBT was significantly reduced from 148±101 min to 108±56 min (p<0.05). While only 25% of the "before" patients received PCI within 90 min after arrival, 50% of the "after" patients received PCI within 90 min (p<0.05). There were no significant differences between two groups in other outcomes (postprocedural TIMI flow, mortality, subsequent stroke, heart failure, shock, reinfarction, length of stay in intensive care unit, and the total hospital length of stay). In conclusion, mandating emergency physicians to directly notify interventional cardiologists of all STEMI patients reduces DTBT