A novel flavobacterial phage abundant during green tide, representing a new viral family, Zblingviridae.

Flavobacteriia are the dominant and active bacteria during algal blooms and play an important role in polysaccharide degradation. However, little is known about phages infecting Flavobacteriia, especially during green tide. In this study, a novel virus, vB_TgeS_JQ, infecting Flavobacteriia was isolated from the surface water of the Golden Beach of Qingdao, China. Transmission electron microscopy demonstrated that vB_TgeS_JQ had the morphology of siphovirus. The experiments showed that it was stable from -20°C to 45°C and pH 5 to pH 8, with latent and burst periods both lasting for 20 min. Genomic analysis showed that the phage vB_TgeS_JQ contained a 40,712-bp dsDNA genome with a GC content of 30.70%, encoding 74 open-reading frames. Four putative auxiliary metabolic genes were identified, encoding electron transfer-flavoprotein dehydrogenase, calcineurin-like phosphoesterase, phosphoribosyl-ATP pyrophosphohydrolase, and TOPRIM nucleotidyl hydrolase. The abundance of phage vB_TgeS_JQ was higher during Ulva prolifera (U. prolifera) blooms compared with other marine environments. The phylogenetic and comparative genomic analyses revealed that vB_TgeS_JQ exhibited significant differences from all other phage isolates in the databases and therefore was classified as an undiscovered viral family, named Zblingviridae. In summary, this study expands the knowledge about the genomic, phylogenetic diversity and distribution of flavobacterial phages (flavophages), especially their roles during U. prolifera blooms. IMPORTANCE: The phage vB_TgeS_JQ was the first flavobacterial phage isolated during green tide, representing a new family in Caudoviricetes and named Zblingviridae. The abundance of phage vB_TgeS_JQ was higher during the Ulva prolifera blooms. This study provides insights into the genomic, phylogenetic diversity, and distribution of flavophages, especially their roles during U. prolifera blooms.

Discrepancies between author- and industry-reported disclosures of financial relationships at an annual gynecologic oncology research meeting.

OBJECTIVE: Trillions of dollars pass to physicians from industry-related businesses annually, leading to many opportunities for financial conflicts of interest. The Open Payments Database (OPD) was created to ensure transparency. We describe the industry relationships as reported in the OPD for presenters at the 2019 Society of Gynecologic Oncology (SGO) Annual Meeting and evaluate concordance between author disclosures of their financial interests and information provided by the OPD. METHODS: This is an observational, cross-sectional study. Disclosure data were collected from authors with oral and featured abstract presentations in the 2019 SGO annual conference. These disclosures were compared to data available for each author in the 2018 OPD, which included the amount and nature of industry payments. RESULTS: We examined the disclosures of 301 authors who met inclusion criteria. Of 161 authors who had disclosure statements on their presentations,147 reported "no disclosures," and 14 disclosed industry relationships. The remaining 140 did not list any disclosure information. Sixty percent (184/301) of authors had industry relationships in the 2018 OPD, including 173 of 287 (60.3%) of authors who either reported no disclosures or did not have disclosure data available in their presentations. These transactions totaled over 43 million USD from 122 different companies, with most payments (46%) categorized as "Research or Associated Research." Accurate disclosure reporting was associated with receiving higher payments or research payments, and being a presenting author. CONCLUSIONS: Most authors at the SGO annual conference did not correctly disclose their industry relationships when compared with their entries in the OPD.

A low-cost approach to salpingectomy at cesarean delivery.

There is increasing adoption of opportunistic salpingectomy for ovarian cancer prevention at the time of gynecologic surgery, which includes the postpartum period. However, there is no consensus on an ideal surgical approach for the parturient vasculature. We describe a safe, low-cost, and accessible approach for bilateral salpingectomy during cesarean delivery that we call the "Mesosalpinx Isolation Salpingectomy Technique" (MIST) that can guide institutions to standardize their postpartum salpingectomy procedures when advanced vessel-sealing devices are not available. In the MIST technique, avascular windows are created within the mesosalpinx close to the tubal vessels. The vasculature is thus fully skeletonized and isolated from the adjacent mesosalpinx before suture ligation, which ensures security of the free-tie to the individual vessels and avoids sharp injury to the mesosalpinx. Not using vessel-sealing devices also eliminates the risk of thermal injury to the adjacent ovarian tissue and vasculature and potentially achieves a cost-savings for the hospital and patient. MIST has been performed in 141 cesarean deliveries in the past 4 years. There were no noted bleeding complications during the salpingectomy procedure, blood transfusions, or instances of postoperative surgical reexploration. In our experience, a surgeon who is new to the procedure takes approximately 15 minutes to complete a bilateral salpingectomy. Those surgeons who are experienced in MIST need only 5 minutes. A video is included that demonstrates the technique.

A Genome Resource of Setosphaeria turcica, Causal Agent of Northern Leaf Blight of Maize.

The heterothallic ascomycete Setosphaeria turcica (anamorph Exserohilum turcicum) causes northern corn leaf blight, which results in devastating yield losses and a reduction in feed value. Although genome sequences of two model strains of the pathogen are available (https://mycocosm.jgi.doe.gov/mycocosm/home), previous drafts were assembled using short read technologies, making evolutionary and genetic linkage inferences difficult. Here, race 23N of S. turcica strain Et28A was sequenced again using Illumina HiSeq and PacBio Sequel technologies, and assembled to approximately 43,480,261 bp on 30 scaffolds. In all, 13,183 protein-coding genes were predicted, 13,142 of them were well annotated. This S. turcica genome resource is important for understanding the genetics behind pathogen evolution and infection mechanisms.

Experimental study to optimize configurations of PCD Spectral CT.

BACKGROUND: High dose efficiency of photon counting detector based spectral CT (PCD-SCT) and its value in some clinical diagnosis have been well acknowledged. However, it has not been widely adopted in practical use for medical diagnosis and security inspection. OBJECTIVE: To evaluate the influence on PCD-SCT from multiple aspects including the number of energy channels, k-edge materials, energy thresholding, basis functions in spectral information decomposition, and the combined optimal setting for these parameters and configurations. METHODS: Basis material decomposition after spatial reconstruction is applied for PCD-SCT. A "one-step" synthesis method, merging decomposition with synthesis, is proposed to obtain virtual monochromatic images. An I-RMSE is computed using the bias part of I-RMSE to describe the difference of a synthesized signal from ground truth and the standard deviation part of I-RMSE to express the noise level. In addition, virtual monochromatic images commonly used in the medical area are also synthesized. Both numerical simulations and practical experiments are conducted for validation. RESULTS: Results indicated that the I-RMSE for matters significantly reduced with an increased number of energy channels compared with dual-energy channel. The maximum reduction is 6% for triple-, 18% for quadruple-and 24% for quintuple-energy, respectively. However, the improvement is not linear, and also slows down after the number of energy channels reaches a certain number. Contrast agents of high concentration can introduce up to 50% error to surrounding matters. Moreover, different energy partitions influence the total error, which demonstrates the necessity of energy threshold optimization. Last, the optimal basis-material combination varies according to targeted imaging matters and the interested monochromatic energies. CONCLUSIONS: Gain from more energy channels could be significant with the increase of energy channel number. Introduction of contrast agents in scanned objects will increase overall error in spectral CT imaging. Energy thresholding optimization is beneficial for information recovery. Moreover, the choice of basis materials could also be important to obtain low noise results. With these studies of the effect from various configurations for PCD-SCT, one may optimize the configuration of PCD-SCT accordingly.

Implantation rates subsequent to the transfer of embryos produced at different phases during double stimulation of poor ovarian responders.

To compare the implantation capacity of embryos obtained at different phases of double stimulation (DS) of poor ovarian responders, 153 DS cycles were analysed retrospectively. As part of the DS protocol, antral follicles were stimulated continuously during both the follicular and luteal phases. Fresh embryos obtained in both phases were cryopreserved and transferred in the next artificial cycle. The mean number of oocytes retrieved, MII oocytes and zygotes with two pronuclei was significantly higher for collections during luteal-phase stimulation. Furthermore, the dose of exogenous gonadotropin administered was higher during the luteal phase. The rate of clinical pregnancy and embryo implantation increased progressively from pure follicular phase embryos to mixed embryos to pure luteal phase embryos. Embryos produced during the luteal phase resulted in higher implantation rates.

Inpatient Laparoscopic Hysterectomy in the United States: Trends and Factors Associated With Approach Selection.

STUDY OBJECTIVE: To examine utilization patterns of different laparoscopic approaches in inpatient hysterectomy and identify patient and hospital characteristics associated with the selection of specific laparoscopic approaches. DESIGN: Using data from the 2007 to 2012 National (Nationwide) Inpatient Sample (NIS), we identified adult women undergoing inpatient laparoscopic hysterectomy for nonobstetric indications based on International Classification of Diseases, Ninth Revision, Clinical Modification codes. Benign cases were categorized based on laparoscopic approach, classified as total laparoscopic hysterectomy (TLH), laparoscopic-assisted vaginal hysterectomy (LAVH), or laparoscopic supracervical hysterectomy (LSH). We assessed changes in the use of these approaches during 2007 to 2012, and used multinomial logistic regression to examine the association of patient and hospital characteristics with the choice of laparoscopic approach in 2012. The NIS sample weights were applied to generate nationally representative estimates. DESIGN CLASSIFICATION: Retrospective study (Canadian Task Force classification III). SETTING: Hospital inpatient care nationwide. PATIENTS: Female adult patients in the NIS database who underwent an inpatient laparoscopic hysterectomy between 2007 and 2012. INTERVENTION: Inpatient laparoscopic hysterectomy. MEASUREMENTS AND MAIN RESULTS: Of the inpatient laparoscopic hysterectomies performed in 2012, 83.2% were for benign indications. The TLH approach accounted for 48.3% of all laparoscopic hysterectomies, followed by LAVH at 37.3% and LSH at 14.4%. Robotic assistance was reported in 45.0% of all cases and 72.3% of malignant hysterectomies. An examination of temporal trends during 2007 to 2012 demonstrates a shift in the laparoscopic approach from LAVH toward TLH, with a slight decrease in LSH. Patient race/ethnicity, income, indication for hysterectomy, and comorbid conditions, as well as hospital teaching status, urban/rural location, bed size, type of ownership, and geographic region, were significantly associated with the choice of laparoscopic approach. CONCLUSION: Benign laparoscopic hysterectomy is increasingly performed as TLH rather than LAVH. In addition to clinical factors, the selection of laparoscopic approach is influenced by patient socioeconomic and hospital characteristics.

Hindbrain regional growth in preterm newborns and its impairment in relation to brain injury.

Premature birth globally affects about 11.1% of all newborns and is a risk factor for neurodevelopmental disability in surviving infants. Histology has suggested that hindbrain subdivisions grow differentially, especially in the third trimester. Prematurity-related brain injuries occurring in this period may selectively affect more rapidly developing areas of hindbrain, thus accompanying region-specific impairments in growth and ultimately neurodevelopmental deficits. The current study aimed to quantify regional growth of the cerebellum and the brainstem in preterm neonates (n = 65 with individually multiple scans). We probed associations of the regional volumes with severity of brain injury. In neonates with no imaging evidence of injury, our analysis using a mixed-effect linear model showed faster growth in the pons and the lateral convexity of anterior/posterior cerebellar lobes. Different patterns of growth impairment were found in relation to early cerebral intraventricular hemorrhage and cerebellar hemorrhage (P < 0.05), likely explaining different mechanisms through which neurogenesis is disrupted. The pattern of cerebellar growth identified in our study agreed excellently with details of cerebellar morphogenesis in perinatal development, which has only been observed in histological data. Our proposed analytic framework may provide predictive imaging biomarkers for neurodevelopmental outcome, enabling early identification and treatment of high-risk patients. Hum Brain Mapp 37:678-688, 2016. © 2015 Wiley Periodicals, Inc.

Risk factors and management of perinatal genital hematoma: A single, tertiary medical center retrospective study in China.

OBJECTIVES: The goal of this study was to identify the risk factors associated with puerperal genital hematoma (PGHA) and analyze the management strategies employed and the resulting maternal outcomes. METHODS: This retrospective cohort study examined the pregnant women delivering vaginally with PGHA in Peking University Third Hospital during January 2002 to December 2021. Exploratory data analysis was performed to assess mean, standard deviation (SD), frequency, percentage and percentiles. Independent-samples t-test was performed for continuous variables. Chi-squared test was performed to compare categorical data. RESULTS: A total of 47 women with PGHA were included, and 94 matched controls were enrolled during the same study period. Compared with the control group, labor induction (34.0% vs. 9.6%, P = 0.000) and episiotomy (66.0% vs. 31.9%, P = 0.000) were more frequently performed in PGHA cases. There was a significantly higher incidence of postpartum hemorrhage (PPH) (53.2% vs. 6.4%, P = 0.000) in PGHA patients than in controls. Compared with the patients with <5 cm hematoma, the proportion of prenatal anemia (25.8% vs. 0.0%, P = 0.027) and the incidence of PPH (67.7% vs. 25.0%, P = 0.005) were significantly higher in patients with ≥5 cm hematoma. In comparison, the active period was significantly shorter (3.1 ± 1.9 vs. 5.1 ± 3.0, P = 0.031) in patients with ≥5 cm hematoma. There were significant differences in perineal pain and swelling (31.3% vs. 67.7%, P = 0.017), vulva hematoma (93.8% vs. 48.4%, P = 0.002) and surgical treatment (62.5% vs. 96.8%, P = 0.002). Nearly half of the patients in the ≥5 cm group underwent secondary suture (41.9% vs. 6.3%, P = 0.011). In patients with PGHA detected after more than 2 h, the body mass index was substantially higher (24.5 ± 4.3 vs. 21.4 ± 2.7, P = 0.011), and the weight gain during pregnancy (14.1 ± 4.3 vs. 11.4 ± 3.5, P = 0.021) was significantly lower. Compared with the patients in PGHA without PPH, age (31.7 ± 4.4 vs. 29.4 ± 2.6, P = 0.033) and newborn birth weight (3367 ± 390 g vs. 3110 ± 419 g, P = 0.045) were considerably higher in PGHA cases with PPH, and the platelet count ([182 ± 44] × 109/L vs. [219 ± 51] × 109/L, P = 0.015) was significantly lower. CONCLUSIONS: Pregnant women who underwent labor induction and episiotomy had a higher incidence of PGHA. The PGHA-related PPH rate is significantly increased. Active surgical treatment is recommended for patients with ≥5 cm hematoma.

Characteristics and treatment for severe postpartum haemorrhage in different midwifery hospitals in one district of Beijing in China: an institution-based, retrospective cohort study.

OBJECTIVE: To identify the characteristics and treatment approaches for patients with severe postpartum haemorrhage (SPPH) in various midwifery institutions in one district in Beijing, especially those without identifiable antenatal PPH high-risk factors, to improve regional SPPH rescue capacity. DESIGN: Retrospective cohort study. SETTING: This study was conducted at 9 tertiary-level hospitals and 10 secondary-level hospitals in Haidian district of Beijing from January 2019 to December 2022. PARTICIPANTS: The major inclusion criterion was SPPH with blood loss ≥1500 mL or needing a packed blood product transfusion ≥1000 mL within 24 hours after birth. A total of 324 mothers with SPPH were reported to the Regional Obstetric Quality Control Office from 19 midwifery hospitals. OUTCOME MEASURES: The pregnancy characteristics collected included age at delivery, gestational weeks at delivery, height, parity, delivery mode, antenatal PPH high-risk factors, aetiology of PPH, bleeding amount, PPH complications, transfusion volume and PPH management. SPPH characteristics were compared between two levels of midwifery hospitals and their association with antenatal PPH high-risk factors was determined. RESULTS: SPPH was observed in 324 mothers out of 106 697 mothers in the 4 years. There were 74.4% and 23.9% cases of SPPH without detectable antenatal PPH high-risk factors in secondary and tertiary midwifery hospitals, respectively. Primary uterine atony was the leading cause of SPPH in secondary midwifery hospitals, whereas placental-associated disorders were the leading causes in tertiary institutions. Rates of red blood cell transfusion over 10 units, unscheduled returns to the operating room and adverse PPH complications were higher in patients without antenatal PPH high-risk factors. Secondary hospitals had significantly higher rates of trauma compared with tertiary institutions. CONCLUSION: Examining SPPH cases at various institutional levels offers a more comprehensive view of regional SPPH management and enhances targeted training in this area.

ELTS-Net: An enhanced liver tumor segmentation network with augmented receptive field and global contextual information.

The liver is one of the organs with the highest incidence rate in the human body, and late-stage liver cancer is basically incurable. Therefore, early diagnosis and lesion location of liver cancer are of important clinical value. This study proposes an enhanced network architecture ELTS-Net based on the 3D U-Net model, to address the limitations of conventional image segmentation methods and the underutilization of image spatial features by the 2D U-Net network structure. ELTS-Net expands upon the original network by incorporating dilated convolutions to increase the receptive field of the convolutional kernel. Additionally, an attention residual module, comprising an attention mechanism and residual connections, replaces the original convolutional module, serving as the primary components of the encoder and decoder. This design enables the network to capture contextual information globally in both channel and spatial dimensions. Furthermore, deep supervision modules are integrated between different levels of the decoder network, providing additional feedback from deeper intermediate layers. This constrains the network weights to the target regions and optimizing segmentation results. Evaluation on the LiTS2017 dataset shows improvements in evaluation metrics for liver and tumor segmentation tasks compared to the baseline 3D U-Net model, achieving 95.2% liver segmentation accuracy and 71.9% tumor segmentation accuracy, with accuracy improvements of 0.9% and 3.1% respectively. The experimental results validate the superior segmentation performance of ELTS-Net compared to other comparison models, offering valuable guidance for clinical diagnosis and treatment.

[Research of placental vascular distribution and clinical outcome in monochorionic twins].

OBJECTIVE: To study the placental vascular distribution of monochorionic (MC) twins with twin-to-twin transfusion syndrome (TTTS) or birth weight discordance. METHODS: Twenty-eight MC placentas were injected in Peking University Third Hospital between Feb. 2010 and Feb. 2011. The vascular distribution type (parallel, crossed, mixed and monoamniotic), the anastomosis of vessels and the placental sharing were recorded. The outcome of pregnancy and the placental characteristics of birth weight discordance (birth weight discordance≥20%) in non-TTTS MC twins were analyzed. RESULTS: (1) The outcome of pregnancy: the miscarriage or gestational weeks of 28 MC twins were 20 to 38 weeks (median of 35 weeks). Six cases were TTTS, 3 of which received fetoscopic laser occlusion of communicating vessels (FLOC). There were 48 live births, with an average birth weight of (2036±623) g. (2) Type of placental vascular distribution:in the 28 MC placentas, number of parallel, crossed, mixed and monoamniotic type of placental vascular distribution were 4 (14%), 14 (50%), 6 (21%) and 4 (14%) cases, respectively. No parallel type was found in TTTS. There was no significant difference of vascular anastomosis or unequal placental sharing among the different placental vascular distribution types (P>0.05). (3) Characteristics of placental vascular distribution in birth weight discordance twins:there were 20 non-TTTS MC twin pregnancies, all of which got live births of both babies. Birth weight discordance equal to or more than 20% was found in 6 pairs of newborns, while birth weight discordance less than 20% was found in the rest 14 cases. Ratio of unequal placental sharing was significantly different between the two groups (P<0.01). There was no significant difference of umbilical cord insertion, placental vascular distribution and anastomosis in the two groups (P>0.01). CONCLUSIONS: Vascular distribution type of MC twins might be related to TTTS. Unequal placental sharing is a risk factor of birth weight discordance in non-TTTS MC twins.

Evaluation of Cesarean Rates for Term, Singleton, Live Vertex Deliveries in China in 2020 Among Women With No Prior Cesarean Delivery.

Importance: Substantial regional variation in cesarean delivery rates has been reported in China, but there is a lack of reports on hospital-level variation in these rates among low-risk deliveries. Objectives: To evaluate hospital variation in cesarean rates in China for term, singleton, live vertex deliveries among women with no prior cesarean delivery and to estimate contributions of individual and hospital factors. Design, Setting, and Participants: This nationwide cross-sectional study used data from maternal patient discharge records collected by the Hospital Quality Monitoring System in China from January 1 to December 31, 2020. Pregnant female individuals aged 15 to 49 years (referred to hereafter as women) with at least 1 live birth were included, and low-risk deliveries were defined as term, singleton, live, vertex deliveries with no prior cesarean delivery. Exposures: Birth by cesarean delivery. Main Outcomes and Measures: The main outcome was cesarean delivery rate by hospital. Hierarchical logistic regression analysis was used to calculate the adjusted cesarean rate and to estimate the percentage of hospital variation in low-risk deliveries explained by individual and hospital factors. Results: Among the 7 635 149 deliveries identified from 4359 hospitals in 31 provinces of mainland China, 6 599 468 (86.4%) were considered low risk. Of overall and low-risk deliveries, 3 400 162 and 2 638 097 were cesarean deliveries, corresponding to mean rates of 44.5% and 40.0%, respectively. The mean (SD) maternal age for overall and low-risk deliveries was 29.1 (4.0) and 28.8 (4.8) years, respectively, and mothers were more likely to be of Han ethnicity (89.5%). Cesarean rates varied widely among hospitals, with absolute differences between the 5th and 95th percentiles of 53.5% (19.4%-72.9%) for overall deliveries and 56.8% (14.3%-71.1%) for low-risk deliveries. Large absolute differences remained after adjusting for maternal characteristics, with rates of 47.4% (19.1%-66.5%) for overall deliveries and 52.6% (15.0%-67.6%) for low-risk deliveries. Among low-risk deliveries, hospital factors (eg, hospital province location) explained 31.3% of the hospital variation in cesarean rate and individual factors explained an additional 2.0%. Conclusions and Relevance: The findings of this cross-sectional study suggest that cesarean rates varied markedly among hospitals in China in 2020, which may be attributable to hospital rather than individual factors. Future work is needed to design hospital-level initiatives to optimize cesarean use, particularly among low-risk deliveries.

Hospital variations in caesarean delivery rates: An analysis of national data in China, 2016-2020.

Background: The impact of China's use of caesarean delivery on global public health has been a long-term concern. The number of private hospitals is increasing in China and likely driving up caesarean delivery rates, yet specifics remain unknown. We aimed to investigate variations in caesarean delivery rates across and within hospital types in China. Methods: We retrieved data on hospital characteristics and national hospital-level annually aggregated data on the number of deliveries and caesarean deliveries from 2016-2020, covering 7085 hospitals in 31 provinces of mainland China, from the National Clinical Improvement System. We categorized hospitals as public-non-referral (n = 4103), public-referral (n = 1805) and private (n = 1177). Among the private hospitals, 89.1% (n = 1049) were non-referral regarding obstetrical services for uncomplicated pregnancies. Results: Among 38 517 196 deliveries, 16 744 405 were caesarean, giving an overall rate of 43.5% with a minor range of 42.9%-43.9% over time. Median rates differed across hospital types, from 47.0% (interquartile range (IQR) = 39.8%-55.9%) in public-referral, 45.8% (36.2%-55.8%) in private, and 40.3% (30.6%-50.6%) in public-non-referral hospitals. The stratified analyses corroborated the results, except for the northeastern region, where the median rates did not differ across the public-non-referral (58.9%), public-referral (59.3%), and private (58.8%) hospitals, while all ranked higher than the other regions, regardless of hospital type and urbanization levels. The rates within hospital types differed as well, especially in the rural areas of the western region of China, where the difference of rates between the 5th and 95th percentiles was 55.6% (IQR = 4.9%-60.5%) in public-non-referral, 51.5% (IQR = 19.6%-71.1%) in public-referral, and 64.6% (IQR = 14.8%-79.4%) in private hospitals. Conclusions: Variation across hospital types in China was pronounced, with the highest rates either in public-referral or private hospitals, except in the northeastern region, where no variation was observed among the high rates of caesarean deliveries. Variation within each hospital type was pronounced, especially in rural areas of the western region.

[Left ovarian vein thrombosis after cesarean section: a case report].

To investigate the clinical presentation, diagnosis and therapy of the postpartum ovarian vein thrombosis. Retrospective analysis was made of one case in our hospital of postpartum ovarian vein thrombosis. Literature was reviewed to investigate the clinical presentation,diagnosis and therapy of postpartum ovarian vein thrombosis. The patient presented with fever, abdominal pain, lower back pain, and ultrasound showed pyelectasis. Her blood and urine bacterial culture was negative, and the antibiotic treatment had no significant effect, which was diagnosed by CT finally. The patient's blood routine returned to normal 3 days after anti-inflammatory and anticoagulant therapy, and thrombosis was significantly reduced. She was followed-up and her condition was stable. Postpartum ovarian vein thrombosis patients often present with high temperature with unknown causes and one side abdominal pain, and CT diagnosis is needed. Timely and effective anti-inflammatory and anticoagulant therapy can significantly improve the prognosis.

Analytical covariance estimation for iterative CT reconstruction methods.

Covariance of reconstruction images are useful to analyze the magnitude and correlation of noise in the evaluation of systems and reconstruction algorithms. The covariance estimation requires a big number of image samples that are hard to acquire in reality. A covariance propagation method from projection by a few noisy realizations is studied in this work. Based on the property of convergent points of cost funtions, the proposed method is composed of three steps, (1) construct a relationship between the covariance of projection and corresponding reconstruction from cost functions at its convergent point, (2) simplify the covariance relationship constructed in (1) by introducing an approximate gradient of penalties, and (3) obtain an analytical covariance estimation according to the simplified relationship in (2). Three approximation methods for step (2) are studied: the linear approximation of the gradient of penalties (LAM), the Taylor apprximation (TAM), and the mixture of LAM and TAM (MAM). TV and qGGMRF penalized weighted least square methods are experimented on. Results from statistical methods are used as reference. Under the condition of unstable 2nd derivative of penalties such as TV, the covariance image estimated by LAM accords to reference well but of smaller values, while the covarianc estimation by TAM is quite off. Under the conditon of relatively stable 2nd derivative of penalties such as qGGMRF, TAM performs well and LAM is again with a negative bias in magnitude. MAM gives a best performance under both conditions by combining LAM and TAM. Results also show that only one noise realization is enough to obtain reasonable covariance estimation analytically, which is important for practical usage. This work suggests the necessity and a new way to estimate the covariance for non-quadratically penalized reconstructions. Currently, the proposed method is computationally expensive for large size reconstructions.Computational efficiency is our future work to focus.

Vasectomy interest and awareness among patients and their partners in prenatal clinics in the United States.

OBJECTIVE: Although vasectomy is safer, more effective and less expensive than tubal ligation, rates of permanent contraception are consistently higher in women than in men. We sought to explore vasectomy interest and awareness in patients and their partners during prenatal visits, a time when contraceptive counselling is typically performed. METHODS: Anonymous surveys were distributed between January and July 2019 to a cross-sectional, convenience sample of pregnant women and their partners, if available, presenting for outpatient prenatal care at two hospitals (one public, one private) serving different patient populations in Chicago, Illinois, USA. Survey questions gauged participant awareness and interest in vasectomies. RESULTS: Surveys were completed by 436 individuals (78% female, 24% male). Seventy percent of respondents indicated interest in vasectomy after achieving optimal family size, but most respondents had never discussed it with their healthcare provider. Factors associated with vasectomy interest included being partnered, having a lower household income, and knowing someone who has had a vasectomy. Almost 50% of respondents would be interested in obtaining information about vasectomies from their obstetrician or prenatal care provider. CONCLUSIONS: Many patients and their male partners in the prenatal clinic setting were interested in vasectomy as a method for permanent contraception, but most respondents had never received counselling. Since comprehensive prenatal care includes contraceptive planning, obstetric providers are uniquely positioned to educate individuals on vasectomy.