Improving diagnosing performance for malignant parotid gland tumors using machine learning with multifeatures based on diffusion-weighted magnetic resonance imaging.

In this study, the performance of machine learning in classifying parotid gland tumors based on diffusion-related features obtained from the parotid gland tumor, the peritumor parotid gland, and the contralateral parotid gland was evaluated. Seventy-eight patients participated in this study and underwent magnetic resonance diffusion-weighted imaging. Three regions of interest, including the parotid gland tumor, the peritumor parotid gland, and the contralateral parotid gland, were manually contoured for 92 tumors, including 20 malignant tumors (MTs), 42 Warthin tumors (WTs), and 30 pleomorphic adenomas (PMAs). We recorded multiple apparent diffusion coefficient (ADC) features and applied a machine-learning method with the features to classify the three types of tumors. With only mean ADC of tumors, the area under the curve of the classification model was 0.63, 0.85, and 0.87 for MTs, WTs, and PMAs, respectively. The performance metrics were improved to 0.81, 0.89, and 0.92, respectively, with multiple features. Apart from the ADC features of parotid gland tumor, the features of the peritumor and contralateral parotid glands proved advantageous for tumor classification. Combining machine learning and multiple features provides excellent discrimination of tumor types and can be a practical tool in the clinical diagnosis of parotid gland tumors.

Tracking the Progress of Wireless Infusion Pump Drug Library Updates- A Data-Driven Analysis of Pump Update Delays.

Modern smart infusion pumps are wirelessly connected to a network server for easy data communications. The two-way communication allows uploading of infusion data and downloading of drug library updates. We have discovered significant delays in library updates. This research aimed at studying the drug library update process of one vendor pump and the contributing factors of pump update delays. Our data included BD Alaris™ pump status and infusion reports of two hospital systems (92 and 80 days, respectively, in 2015). We analyzed drug library update progressions at the individual device and fleet levels. To complete a library update, a pump goes through two status transitions: from noncurrent to a new library pending, and from pending to current. On average it took five to nine days for 50% of a pump fleet to become current after a new drug library was disseminated. We confirmed factors that affect noncurrent-to-pending time to include time to first power-on and total power-on time. We also found that high pump utilization promotes shorter pending-to-current time. Two distinctive and important steps of a drug library update on Alaris™ pumps are pending a new library and completing the library installation. To avoid potential patient harm caused by infusion pumps without appropriate drug limits due to update delays, hospitals should monitor the progression of a drug library update on its pump fleet. Potential ways to improve drug library updates on a fleet of pumps include better technologies, improved pump user-interface design, and more staff training.

Proton change of parotid glands after gustatory stimulation examined by magnetic resonance imaging.

The aim of this study was to investigate proton changes of the parotid gland after gustatory stimulation by semi-quantitative parameters and an empirical mathematical model (EMM) using high-temporal-resolution, double-echo, echo-planar imaging (EPI). Approved by a local institutional review board, this study examined 20 parotid glands from 10 healthy volunteers (male:female = 6: 4; age ± standard deviation =35.1 ± 14.1 years) with written informed consent obtained. All participants underwent 1.5-T, double-echo EPI with gustatory stimulation. Semi-quantitative parameters, including maximal drop ratio (MDR), time to peak (TTP), drop slope (DS), recovery slope (RS) and recovery ratio (RR), were calculated. The effect of temporal resolution on parotid functional parameters was evaluated. An EMM comprising an output function ( Sot=Aoe-kot+B) and an input function ( Sint=Ain1-e-kint) was also applied to fit all dynamic curves. Kruskal-Wallis test, Wilcoxon test, linear regression analysis and goodness of fit were used for statistical analysis. p < 0.05 was considered to be statistically significant. The signal intensity dropped significantly after gustatory stimulation on the proton density (PD) image (p < 0.01). MDR was 8.26% in the PD image. MDR and RR were negatively associated with time interval, whereas DS and TTP were significantly positively associated with time interval (all p < 0.05). EMM parametric values derived from PD-time curves of parotid glands were 12.04 ± 6.81%, 6.43 ± 4.23 min-1 , 88.73 ± 6.18%, 8.41 ± 4.86 min-1 and 1.09 ± 1.35 for Ao , ko , B, Ain and kin , respectively. Semi-quantitative functional parameters and EMM parameters using high-temporal-resolution, double-echo EPI allow the quantification of parotid proton changes after gustatory stimulation.

The Synthesis and Assembly Mechanism of Micro/Nano-Sized Polystyrene Spheres and Their Application in Subwavelength Structures.

The following study involved the utilization of dispersion polymerization to synthesize micron/nano-sized polystyrene (PS) spheres, which were then deposited onto a silicon substrate using the floating assembly method to form a long-range monolayer. Subsequently, dry etching techniques were utilized to create subwavelength structures. The adjustment of the stabilizer polyvinylpyrrolidone (PVP), together with changes in the monomer concentration, yielded PS spheres ranging from 500 nm to 5.6 µm in diameter. These PS spheres were suspended in a mixture of alcohol and deionized water before being arranged using the floating assembly method. The resulting tightly packed particle arrangement is attributed to van der Waals forces, Coulomb electrostatic forces between the PS spheres, and surface tension effects. The interplay of these forces was analyzed to comprehend the resulting structure. Dry etching, utilizing the PS spheres as masks, enabled the exploration of the effects of etching parameters on the resultant structures. Unlike traditional dry etching methods controlling RF power and etching gases, in the present study, we focused on adjusting the oxygen flow rate to achieve cylindrical, conical, and parabolic etched structures.

Discernible interindividual patterns of global efficiency decline during theoretical brain surgery.

The concept of functional localization within the brain and the associated risk of resecting these areas during removal of infiltrating tumors, such as diffuse gliomas, are well established in neurosurgery. Global efficiency (GE) is a graph theory concept that can be used to simulate connectome disruption following tumor resection. Structural connectivity graphs were created from diffusion tractography obtained from the brains of 80 healthy adults. These graphs were then used to simulate parcellation resection in every gross anatomical region of the cerebrum by identifying every possible combination of adjacent nodes in a graph and then measuring the drop in GE following nodal deletion. Progressive removal of brain parcellations led to patterns of GE decline that were reasonably predictable but had inter-subject differences. Additionally, as expected, there were deletion of some nodes that were worse than others. However, in each lobe examined in every subject, some deletion combinations were worse for GE than removing a greater number of nodes in a different region of the brain. Among certain patients, patterns of common nodes which exhibited worst GE upon removal were identified as "connectotypes". Given some evidence in the literature linking GE to certain aspects of neuro-cognitive abilities, investigating these connectotypes could potentially mitigate the impact of brain surgery on cognition.

Results and Complications After Single-Stage Repair of Aortopulmonary Window and Interrupted Aortic Arch in a 32-Week Preterm and a Full-Term Neonate.

BACKGROUND An aortopulmonary window (APW) is an uncommon congenital defect of the septation between the ascending aorta and pulmonary trunk. The combination of APW and interrupted aortic arch (IAA) is even rarer, with the hallmark characteristics of high peri-operative mortality and postoperative obstruction of the aortic arch, pulmonary artery, and left main bronchus. These complications often need re-interventions. CASE REPORT We present 2 cases with diagnoses of APW and IAA that were treated with single-stage repair. Case 1: A male 32-week premature newborn (weight 1789 g) had APW type I and IAA type A. He had severe postoperative aortic arch obstruction on postoperative day 1, and we re-intervened promptly. He was still asymptomatic after 6 years. Case 2: A male term neonate had APW type III and IAA type A. He had left vocal cord paralysis and left bronchial compression postoperatively. We applied prolonged noninvasive respiratory supports. The complications resolved without re-intervention on postoperative day 66. Progressive arch stenosis at anastomosis after operation required close follow-up with echocardiography. CONCLUSIONS These 2 reports highlight the feasibility of single-stage surgical repair while addressing 2 challenges: (1) Recurrent arch stenosis: Lower body weight and direct end-to-side anastomosis without patch augmentation could be risk factors for re-intervention. (2) Bronchial compression: Presentation of the second reported case implied that bronchial compression may not warrant immediate re-intervention unless there is complete obstruction, persistent atelectasis, or recurrent infection. Further studies on long-term outcomes of different surgical procedure would help us to clarify the proper way to avoid re-intervention.

Associated factors with parental pregnancy decision-making and use of consultation after a prenatal congenital heart disease diagnosis.

BACKGROUND: Prenatal diagnosis of congenital heart disease (CHD) often leads affected families to experience psychological stress. Pediatric cardiology consultation is important in providing parents with sufficient information and reducing their anxiety to make an informed pregnancy decision. Involving a fetal nurse coordinator may optimize fetal anomaly care. Our study aimed to identify factors associated with parental decision-making for choosing to use pediatric cardiology consultations and pregnancy termination. METHODS: From September 2017 to December 2018, all fetal CHD cases diagnosed in the second trimester from a primary screening clinic in Taiwan were included (n = 145). Univariate and multivariate logistic regression were performed to analyze maternal, fetal, and medical factors for predictors of parental decisions for consultation use and pregnancy termination. RESULTS: Acceptance for fetal nurse coordinator care and pediatric cardiology consultation were 84.8% (n = 123) and 83.4% (n = 121), respectively. Predictors for termination of pregnancy included the following: multiple anomalies (OR: 10.6; 95% CI: 3.6-35.7), chromosomal/genetic abnormalities (OR: 20.2; 95% CI: 3.1-395.8), severe CHDs (OR: 9.8; 95% CI: 4.3-23.4), CHDs that required surgery (OR: 32.4; 95% CI: 11.4-117.8), and physiological single-ventricle (OR: 47.3; 95% CI: 12.4-312.5). Parents who had pediatric cardiology counseling were less likely to terminate the pregnancy (OR: 0.1; 95% CI: 0.0-0.7). Parents with fetal diagnosis having multiple anomalies (OR: 0.2; 95% CI: 0.1-0.7) or chromosomal/genetic abnormalities (OR: 0.1; 95% CI: 0.03-0.9) were less likely to make use of cardiology consultation. Parents who accepted fetal nurse coordinator care were more likely to have pediatric cardiology consultation before pregnancy decision (OR: 149.5, 95% CI: 37.8-821.5). CONCLUSIONS: Anomaly complexity appeared to be a strong predictor for termination of pregnancy beyond non-acceptability of prenatal cardiology consultation. Prenatal cardiology counseling may help support the parental decision to continue with the pregnancy. Incorporation of a fetal nurse coordinator care into the multidisciplinary fetal medicine team improved the acceptability of prenatal consultation.

Clinical outcomes of handmade polytetrafluoroethylene trileaflet-valved conduit used for pulmonary valve replacement.

OBJECTIVES: To mitigate the shortage of homograft sources, the use of handmade trileaflet expanded polytetrafluoroethylene valves in pulmonary valve replacement has shown excellent results from multicentre studies conducted in Japan. However, world-wide data outside Japan are relatively insufficient. This study presents the long-term results of a single surgeon's use of flipped-back trileaflet method in a 10-year case series. METHODS: We have developed an efficient way to make a trileaflet-valved conduit utilizing flipped-back method for pulmonary valve replacement and have employed the technique since 2011. Retrospective data were studied between October 2010 and January 2020. Echocardiography, electrocardiogram, Pro-Brain Natriuretic Peptide and Magnetic Resonance Imaging data were analysed. RESULTS: Fifty-five patients were reviewed and median follow-up duration was 2.9 years. The majority of diagnoses was Tetralogy of Fallot (n = 41), and these patients subsequently underwent secondary pulmonary valve replacement at a median age of 15.6 years. Survival was 92.7% with the longest follow-up period being 10 years. There was no need for reoperation, and freedom from reintervention was 98.0% at 10 years. There were 4 deaths (3 in-hospital and 1 outpatient). One patient eventually received transcatheter pulmonary valve implantation. Postoperative echocardiography showed mild or less pulmonary stenosis and pulmonary regurgitation degree in 92.2% and 92.0% of patients, respectively. Comparable magnetic resonance imaging data (n = 25) showed significant reduction in right ventricular volumes but not in ejection fractions. CONCLUSIONS: Our series showed satisfactory long-term function of handmade flipped-back trileaflet-valved conduit used in our patients. The simple design is efficiently reproducible without complex fabrication process.

Comparative genotoxicity of nitrosamine drinking water disinfection byproducts in Salmonella and mammalian cells.

Nitrosamine water disinfection byproducts (DBPs) are an emerging class of non-halogenated, nitrogen-containing water contaminants. Five nitrosamine DBPs were analyzed for genotoxicity (N-nitrosodimethylamine (NDMA), N-nitrosopiperidine (NPIP), N-nitrosopyrrolidine (NPYR), N-nitrosomorpholine (NMOR) and N-nitrosodiphenylamine (NDPhA). Using Salmonella typhimurium strain YG7108 the descending rank order of mutagenicity was NDMA>NPIP>NMOR>NPYR; NDPhA was not mutagenic. We developed and calibrated an exogenous S9 mix that was highly effective in activating NDMA in Chinese hamster ovary (CHO) cells using the SCGE (Comet) assay. The descending rank order for genotoxicity was NDMA>NPIP>NMOR. NDPhA was genotoxic only at one concentration and NPYR was not genotoxic. The genotoxic potencies in S. typhimurium and CHO cells were highly correlated. Based on their comparative genotoxicity attention should be focused on the generation and occurrence of NDMA, NPIP and NMOR. Current drinking water disinfection processes may need to be modified such that the generation of nitrosamine DBPs is effectively limited in order to protect the environment and the public health.

Improving performance of deep learning models using 3.5D U-Net via majority voting for tooth segmentation on cone beam computed tomography.

Deep learning allows automatic segmentation of teeth on cone beam computed tomography (CBCT). However, the segmentation performance of deep learning varies among different training strategies. Our aim was to propose a 3.5D U-Net to improve the performance of the U-Net in segmenting teeth on CBCT. This study retrospectively enrolled 24 patients who received CBCT. Five U-Nets, including 2Da U-Net, 2Dc U-Net, 2Ds U-Net, 2.5Da U-Net, 3D U-Net, were trained to segment the teeth. Four additional U-Nets, including 2.5Dv U-Net, 3.5Dv5 U-Net, 3.5Dv4 U-Net, and 3.5Dv3 U-Net, were obtained using majority voting. Mathematical morphology operations including erosion and dilation (E&D) were applied to remove diminutive noise speckles. Segmentation performance was evaluated by fourfold cross validation using Dice similarity coefficient (DSC), accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV). Kruskal-Wallis test with post hoc analysis using Bonferroni correction was used for group comparison. P < 0.05 was considered statistically significant. Performance of U-Nets significantly varies among different training strategies for teeth segmentation on CBCT (P < 0.05). The 3.5Dv5 U-Net and 2.5Dv U-Net showed DSC and PPV significantly higher than any of five originally trained U-Nets (all P < 0.05). E&D significantly improved the DSC, accuracy, specificity, and PPV (all P < 0.005). The 3.5Dv5 U-Net achieved highest DSC and accuracy among all U-Nets. The segmentation performance of the U-Net can be improved by majority voting and E&D. Overall speaking, the 3.5Dv5 U-Net achieved the best segmentation performance among all U-Nets.

Aortotracheal fistula after slide tracheoplasty in a patient with dextrocardia, left pulmonary artery sling and tracheal stenosis: a case report.

BACKGROUND: Aortotracheal fistula (ATF) is an uncommon and fatal complication of tracheal or aortic surgery, especially among pediatric patients. CASE PRESENTATION: We reported a case in a 1-year-old boy with dextrocardia, left pulmonary artery sling and long segment tracheal stenosis. He received slide tracheoplasty at 9 months of age and had post-operative refractory granulation at distal trachea status post repeated balloon dilatation and laser vaporization. Episodes of hemoptysis occurred on post-operative day 81. Bronchoscopy revealed a pulsating pseudoaneurysm at lower trachea which ruptured during the procedure Urgent surgical repair under cardiopulmonary bypass with deep hypothermic circulatory arrest was done. No recurrent bleeding or significant neurologic deficits noticed at a 4-month follow-up. CONCLUSION: Congenital anomaly that changes the spatial relationship between trachea and aorta could have contributed to formation of ATF. This warrant future attention when managing tracheal granulation with this not uncommon anatomy.

Evolution of pulmonary valve reconstruction with focused review of expanded polytetrafluoroethylene handmade valves.

OBJECTIVES: Many surgeons develop unique techniques for unmet needs for right ventricular outflow reconstruction to resolve pulmonary regurgitation after corrective surgery for congenital heart diseases. Expanded polytetrafluoroethylene (ePTFE) stands out as a reliable synthetic material, and clinical results with handmade ePTFE valves have been promising. This review focuses on the historical evolution of the use of ePTFE in pulmonary valve replacement and in the techniques for pioneering the translation of the handmade ePTFE trileaflet design for the transcatheter approach. METHODS: We searched for and reviewed publications from 1990 to 2020 in the Pubmed database. Nineteen clinical studies from 2005 to 2019 that focused on ePTFE-based valves were summarized. The evolution of the ePTFE-based valve over 3 decades and recent relevant in vitro studies were investigated. RESULTS: The average freedom from reintervention or surgery in the recorded ePTFE-based valve population was 90.2% at 5 years, and the survival rate was 96.7% at 3 years. CONCLUSIONS: Non-inferior clinical results of this ePTFE handmade valve were revealed compared to allograft or xenograft options for pulmonary valve replacement. Future investigations on transferring ePTFE trileaflet design to transcatheter devices should be considered.

Successful Rescue of a Ruptured Tracheoinnominate Fistula with Extracorporeal Membrane Oxygenation, Endovascular Stents, and Debranching Surgical Bypass.

We reported a case of ruptured tracheoinnominate fistula in a 14-year-old boy with history of repeated sternotomy. Tracheostomy was performed at age 2 years. Slide tracheoplasty was done at age 13 years. He presented to outpatient clinic with episodic hemosputum. Massive blood emanated from stoma during bronchoscopy evaluation. Venous-arterial extracorporeal membrane oxygenation was installed for resuscitation. A contrast-enhanced computed tomography (CT) and angiography confirmed the diagnosis. Immediate control of bleeding was achieved by an endovascular stent graft deployed at innominate artery. Massive hemorrhage recurred on day 7. An aortic arch stent was inserted and all arch vessels debranching via supraclavicular collar excision was performed. A covered stent was used to fenestrate the aortic stent and establish antegrade blood flow to all neck vessels via left common carotid artery. The patient remained stable at 10-month follow-up. Combination of extracorporeal membrane oxygenation, endovascular intervention, and surgical bypass could be effective in treating critical patients.

In vitro study of trileaflet polytetrafluoroethylene conduit and its valve-in-valve transformation.

OBJECTIVES: Handmade trileaflet expanded polytetrafluoroethylene valved conduit developed using the flip-over method has been tailored for pulmonary valve reconstruction with satisfactory outcomes. We investigated the in vitro performance of the valve design in a mock circulatory system with various conduit sizes. In our study, the design was transformed into a transcatheter stent graft system which could fit in original valved conduits in a valve-in-valve fashion. METHODS: Five different sizes of valved polytetrafluoroethylene vascular grafts (16, 18, 20, 22 and 24 mm) were mounted onto a mock circulatory system with a prism window for direct leaflets motion observation. Transvalvular pressure gradients were recorded using pressure transducers. Mean and instant flows were determined via a rotameter and a flowmeter. Similar flip-over trileaflet valve design was then carried out in 3 available stent graft sizes (23, 26 and 28.5 mm, Gore aortic extender), which were deployed inside the valved conduits. RESULTS: Peak pressure gradient across 5 different sized graft valves, in their appropriate flow setting (2.0, 2.5 and 5.0 l/min), ranged from 4.7 to 13.2 mmHg. No significant valve regurgitation was noted (regurgitant fraction: 1.6-4.9%) in all valve sizes and combinations. Three sizes of the trileaflet-valved stent grafts were implanted in the 4 sizes of valved conduits except for the 16-mm conduit. Peak pressure gradient increase after valved-stent graft-in-valved-conduit setting was <10 mmHg in all 4 conduits. CONCLUSIONS: The study showed excellent in vitro performance of trileaflet polytetrafluoroethylene valved conduits. Its valved stent graft transformation provided data which may serve as a reference for transcatheter valve-in-valve research in the future.

Unintended Patient Safety Risks Due to Wireless Smart Infusion Pump Library Update Delays.

OBJECTIVE: Our previous study showed that the issue of drug library update delays on wireless intravenous (IV) infusion pumps of one major vendor was widespread and significant. However, the impact of such a delay was unclear. The objective of this study was to quantify the impact of pump library update delays on patient safety in terms of missed and false infusion programming alerts. METHODS: The study data sets included infusion logs and drug libraries from three hospitals of one health system from January 2015 to December 2016. We identified limit setting changes of any two consecutive drug library versions. We quantified the impact of using outdated drug limit settings by missed and false infusion programming alerts. RESULTS: Twenty-five updates of the drug library were released within the health system during the 2-year period with an average interval of 28.8 days. After a new library version was issued, it took at least 6 days for 50% of all pumps to become up-to-date and 15 days or more to reach 80%. All three hospitals had at least 16% of all IV infusions programmed with outdated libraries. This resulted in 18%, 24.4%, and 27% of false alerts in the three hospitals, respectively. We identified two cases of missed alert infusions of high-risk medications, propofol, and potassium chloride, which could have negatively impacted patient safety. CONCLUSIONS: These findings support our assumption that potential serious harm can happen when IV infusions are administered with outdated drug limit settings due to delays in drug library updates on the pump.

Prevalence of wireless smart-pump drug library update delays.

PURPOSE: Results of a study to estimate the prevalence and severity of delays in wireless updates of smart-pump drug libraries across a large group of U.S. hospitals are reported. METHODS: A prolonged smart-pump drug library update may result in patient harm if a pump is programmed with an incorrect limit setting at the time of drug administration. A retrospective study was conducted using smart-pump alert data extracted from the Regenstrief National Center for Medical Device Informatics (REMEDI) database. The study sample consisted of 49 hospitals in 5 states across the Midwest and Kentucky operated by 12 health systems; all the facilities used a specific brand of smart pump (BD Alaris, Beckton, Dickinson and Company) capable of generating alert data and had consistently contributed alert data to the REMEDI database over a 2-year period. An update delay was defined as the interval from the time a drug library version was replaced to the time of the last infusion alert triggered by the previous version during the study period. RESULTS: Of the 12 health systems, 11 were found to have had drug library update delays during the study period, with delay medians ranging from 22 to 192 days. The overall delay minimum and maximum durations were 0 and 661 days. CONCLUSION: Substantial delays in completion of wireless updates of smart-pump drug libraries were common across a group of hospitals of various sizes.

Prenatal diagnosis of coarctation of the aorta with ventricular septal defect: A case report.

OBJECTIVE: To present an accurate prenatal diagnosis of coarctation of the aorta with ventricular septal defect and to illustrate how early diagnosis in prenatal period with proper referral and counseling can optimize management. CASE REPORT: A case with coarctation of the aorta with ventricle septal defect was found to have an abnormal three vessel view at 12 weeks, and with close follow-ups, coarctation of the aorta with ventricle septal defect was diagnosed at 24 weeks. Following the support from a multidisciplinary team that provided counseling, diagnosis, and follow-ups, the pregnant woman decided to continue with the pregnancy and had a vaginal delivery at a medical center. The newborn made an uneventful recovery after undergoing cardiac surgery on day 9. CONCLUSION: The case demonstrates the role a fetal medicine team plays in diagnosing, supporting, and seamlessly transferring the congenital heart disease case from the first line obstetrician to the cardiac surgeon. A multi-disciplinary team approach was able to lead to improved perinatal outcome of the congenital heart disease case.

Investigating Delays in Updates to Infusion Pump Drug Limit Libraries.

Interoperability is a major challenge in current healthcare systems. It brings big hope for data exchange, but also raises some concern about patient safety. We study the wireless updating of modern infusion pumps and demonstrate the possible flaws in this process. Through analyzing data on drug limit libraries (DLL) versions in one hospital we could identify the delays in distributing DLL updates and the impact these delays might have on patient safety. We found that 31% of all started infusions had used outdated DLL versions, and 22.6% of all alerts were triggered by outdated DLLs. These findings suggest that clinical and operational stakeholders in healthcare systems must address the unreliable interoperability of medical technologies such as seen on infusion pumps. The impact of information inconsistency across healthcare systems might result in use error which would impair patient safety.

17-year experience in surgical management of congenitally corrected transposition of the great arteries: a single-centre's experience.

OBJECTIVES: We report our surgical experience in congenitally corrected transposition of great arteries (CCTGAs) and the long-term follow-up result. METHODS: From January 1995 to February 2012, 56 patients with CCTGA received definite surgical repair; 15 patients received conventional repair (Group I), 18 patients received anatomical repair (Group II) and 23 patients received single ventricular palliation (Group III). They were followed for early and late mortality, long-term survival, postoperative morbidity and reintervention or reoperation. RESULTS: The overall survival rate was 80% at 16 years in Group I, 53% at 13 years in Group II and 100% at 13 years in Group III. After excluding the early surgical mortality, the long-term survival rate was 92% at 16 years in Group I, 64% at 13 years in Group II and 100% at 13 years in Group III. Patients with significant tricuspid valve regurgitation showed the worst outcome after surgery. CONCLUSIONS: Our series showed good results with single ventricular palliation (SVP) in CCTGA with complex anatomy, but the long-term result should be followed. Anatomical repair is the choice of operation only for those with favourable anatomy. The more complicated intracardiac repair may result in late left ventricular outflow tract obstruction, various degrees of atrioventricular block, systemic or pulmonary venous return obstruction and the lack of an ideal conduit (e.g. homograft) for Rastelli reconstruction. Therefore, we preferred SVP in patients with complex and unfavourable anatomy.

A potential risk of overestimating apparent diffusion coefficient in parotid glands.

OBJECTIVES: To investigate transient signal loss on diffusion weighted images (DWI) and overestimation of apparent diffusion coefficient (ADC) in parotid glands using single shot echoplanar DWI (EPDWI). MATERIALS AND METHODS: This study enrolled 6 healthy subjects and 7 patients receiving radiotherapy. All participants received dynamic EPDWI with a total of 8 repetitions. Imaging quality of DWI was evaluated. Probability of severe overestimation of ADC (soADC), defined by an ADC ratio more than 1.2, was calculated. Error on T2WI, DWI, and ADC was computed. Statistical analysis included paired Student t testing and Mann-Whitney U test. A P value less than 0.05 was considered statistically significant. RESULTS: Transient signal loss was visually detected on some excitations of DWI but not on T2WI or mean DWI. soADC occurred randomly among 8 excitations and 3 directions of diffusion encoding gradients. Probability of soADC was significantly higher in radiotherapy group (42.86%) than in healthy group (24.39%). The mean error percentage decreased as the number of excitations increased on all images, and, it was smallest on T2WI, followed by DWI and ADC in an increasing order. CONCLUSIONS: Transient signal loss on DWI was successfully detected by dynamic EPDWI. The signal loss on DWI and overestimation of ADC could be partially remedied by increasing the number of excitations.