Preoperative CT imaging as a tool to predict incisional hernia outcomes following abdominal wall reconstruction: A retrospective cohort analysis

INTRODUCTION

Ventral wall hernia often causes significant morbidity and requires complex abdominal wall reconstruction (AWR). This study aims to determine whether subcutaneous abdominal fat thickness (AFT) measured with preoperative CT scans could predict postoperative outcomes in patients undergoing AWR.

METHODS

A retrospective cohort study was conducted on all patients who underwent AWR at our institution between 2009 and 2021, with a minimum follow-up of 12 months. Using preoperative CT scans, AFT was measured at the xiphoid process, umbilicus, and pubic tubercle, as well as the hernia dimensions. Demographic, operative, and surgical outcome data were also collected and analyzed using statistical tests.

RESULTS

The results showed that 9 of 101 patients (8.9%) experienced hernia recurrence. Smoking was associated with an increased risk of hernia recurrence (p < 0.001) with a predictive odds ratio (OR) of 18.27 (p = 0.041). Increased AFT at the xiphoid (p = 0.005), umbilicus (p < 0.001), and pubic tubercle (p < 0.001) were also associated with hernia recurrence and risk of infection. Only AFT at the pubic tubercle reached significance in the regression model predicting recurrence (OR=1.10; p = 0.030) and infection (OR=1.04; p = 0.021). A cut-off value of 67 mm was associated with a positive predictive value of 42.14% (sensitivity of 67% and specificity of 91%). Hernia defect area was not associated with risk of recurrence or infection.

CONCLUSIONS

Smoking and increased AFT at the pubic tubercle are significant predictive factors for recurrence and infection in patients undergoing AWR, and preoperative optimization should focus on reducing these factors.

A National Referral Service for Paediatric Brachytherapy: An Evolving Practice and Outcomes Over 13 Years

AIMS

Most children requiring radiotherapy receive external beam treatment and few have tumours suitable for brachytherapy. No paediatric radiotherapy centre will treat enough patients from its own normal catchment population for expertise in brachytherapy to be developed and sustained. Following discussion and agreement in the national paediatric radiotherapy group, a service for paediatric brachytherapy in the UK has been developed. We report the process that has evolved over more than 10 years, with survival and functional outcome results.

MATERIALS AND METHODS

Since 2009, potential patients have been referred to the central paediatric oncology multidisciplinary team meeting, where imaging, pathology and treatment options are discussed. Since 2013, the National Soft Tissue Sarcoma Advisory Panel has also reviewed most patients, with the principal aim of advising on the most suitable primary tumour management for complex patients. Clinical assessment and examination under anaesthetic with biopsies may be undertaken to confirm the appropriateness of brachytherapy, either alone or following conservative surgery. Fractionated high dose rate brachytherapy was delivered to a computed tomography planned volume after implantation of catheters under ultrasound imaging guidance. Since 2019, follow-up has been in a dedicated multidisciplinary clinic.

RESULTS

From 2009 to 2021 inclusive, 35 patients (16 female, 19 male, aged 8 months to 17 years 6 months) have been treated. Histology was soft-tissue sarcoma in 33 patients and carcinoma in two. The treated site was pelvic in 31 patients and head and neck in four. With a median follow-up of 5 years, the local control and overall survival rates are 100%. Complications have been few, and functional outcome is good.

CONCLUSION

Brachytherapy is effective for selected paediatric patients, resulting in excellent tumour control and good functional results. It is feasible to deliver paediatric brachytherapy at a single centre within a national referral service.

New insights from nanotechnology in SARS-CoV-2 detection, treatment strategy, and prevention

The recent outbreak of SARS-CoV-2 resulted into the deadly COVID-19 pandemic, which has made a profound impact on mankind and the world health care system. SARS-CoV-2 is mainly transmitted within the population via symptomatic carriers, enters the host cell via ACE2 and TMPSSR2 receptors and damages the organs. The standard diagnostic tests and treatment methods implemented lack required efficiency to beat SARS-CoV-2 in the race of its spreading. The most prominently used diagnostic test,reverse transcription-polymerase chain reaction (a nucleic acid-based method), has limitations including a prolonged time taken to reveal results, limited sensitivity, a high rate of false negative results, and lacking specificity due to a homology with other viruses. Furthermore, as part of the treatment, antiviral drugs such as remdesivir, favipiravir, lopinavir/ritonavir, chloroquine, daclatasvir, atazanavir, and many more have been tested clinically to check their potency for the treatment of SARS-CoV-2 but none of these antiviral drugs are the definitive cure or suitable prophylaxis. Thus, it is always required to combat SARS-CoV-2 spread and infection for a better and precise prognosis. This review answers the above mentioned challenges by employing nanomedicine for the development of improved detection, treatment, and prevention strategies for SARS-CoV-2. In this review, nanotechnology-based detection methods such as colorimetric assays, photothermal biosensors, molecularly imprinted nanoparticles sensors, electrochemical nanoimmunosensors, aptamer-based biosensors have been discussed. Furthermore, nanotechnology-based treatment strategies involving polymeric nanoparticles, metallic nanoparticles, lipid nanoparticles, and nanocarrier-based antiviral siRNA delivery have been depicted. Moreover, SARS-CoV-2 prevention strategies, which include the nanotechnology for upgrading personal protective equipment, facemasks, ocular protection gears, and nanopolymer-based disinfectants, have been also reviewed. This review will provide a one-site informative platform for researchers to explore the crucial role of nanomedicine in managing the COVID-19 curse more effectively.

Monte Carlo simulations and phantom validation of low-dose radiotherapy to the lungs using an interventional radiology C-arm fluoroscope

PURPOSE

To use MC simulations and phantom measurements to investigate the dosimetry of a kilovoltage x-ray beam from an IR fluoroscope to deliver low-dose (0.3-1.0 Gy) radiotherapy to the lungs.

MATERIALS AND METHODS

PENELOPE was used to model a 125 kV, 5.94 mm Al HVL x-ray beam produced by a fluoroscope. The model was validated through depth-dose, in-plane/cross-plane profiles and absorbed dose at 2.5-, 5.1-, 10.2- and 15.2-cm depths against the measured beam in an acrylic phantom. CT images of an anthropomorphic phantom thorax/lungs were used to simulate 0.5 Gy dose distributions for PA, AP/PA, 3-field and 4-field treatments. DVHs were generated to assess the dose to the lungs and nearby organs. Gafchromic film was used to measure doses in the phantom exposed to PA and 4-field treatments, and compared to the MC simulations.

RESULTS

Depth-dose and profile results were within 3.2% and 7.8% of the MC data uncertainty, respectively, while dose gamma analysis ranged from 0.7 to 1.0. Mean dose to the lungs were 1.1-, 0.8-, 0.9-, and 0.8- Gy for the PA, AP/PA, 3-field, and 4-field after isodose normalization to cover ∼ 95% of each lung volume. Skin dose toxicity was highest for the PA and lowest for the 4-field, and both arrangements successfully delivered the treatment on the phantom. However, the dose distribution for the PA was highly non-uniform and produced skin doses up to 4 Gy. The dose distribution for the 4-field produced a uniform 0.6 Gy dose throughout the lungs, with a maximum dose of 0.73 Gy. The average percent difference between experimental and Monte Carlo values were -0.1% (range -3% to +4%) for the PA treatment and 0.3% (range -10.3% to +15.2%) for the 4-field treatment.

CONCLUSION

A 125 kV x-ray beam from an IR fluoroscope delivered through two or more fields can deliver an effective low-dose radiotherapy treatment to the lungs. The 4-field arrangement not only provides an effective treatment, but also significant dose sparing to healthy organs, including skin, compared to the PA treatment. Use of fluoroscopy appears to be a viable alternative to megavoltage radiation therapy equipment for delivering low-dose radiotherapy to the lungs.

Signal Processing and Classification for Electroencephalography Based Motor Imagery Brain Computer Interface

Brain Computer Interface (BCI) is a fast growing area of research to enable communication between our brains and computers. EEG based motor imagery BCI involves the user imagining movement, the subsequent recording and signal processing on the electroencephalogram signals from the brain, and the translation of those signals into specific commands. Ultimately, motor imagery BCI has the potential to be applied to helping those with special abilities recover motor control. This paper presents an evaluation of performance for EEG based motor imagery BCI with a classification accuracy of 80.2%, making use of features extracted using the Fast Fourier Transform and the Discrete Wavelet Transform, and classification is done using an Artificial Neural Network. It goes on to conclude how the performance is affected by the particular feature sets and neural network parameters.

Validity, reliability, and transcultural adaptations of the Bayley Scales of Infant and Toddler Development (BSID-III-NL) for children in Suriname

BACKGROUND

A valid and reliable measure of infant neurodevelopment is needed in Suriname, South America. The Bayley Scales of Infant and Toddler Development, 3rd edition (BSID-III), was created for evaluation of United States infants and toddlers and subsequently validated for use in Dutch speaking infants of the Netherlands (BSID-III-NL). Given that Suriname was a previous Dutch colony and Dutch remains the national language of Suriname, this study sought to evaluate the psychometric properties of the BSID-III-NL in Suriname.

AIMS

Given that the cultural context differs between Suriname, the United States, and the Netherlands, the aims of this study were to determine if any cultural adaptations of the BSID-III-NL were needed for Surinamese infants and to evaluate its psychometric properties.

METHODS

Two hundred and ninety-nine infants between the ages of 10 to 26 months were assessed in three geographic regions of Suriname between May 2018 and July 2019. Minor adaptations to the BSID-III-NL imagery were made based on the input of Surinamese pediatricians and neuropsychologists who were also involved in the administration of the BSID-III-NL in Suriname. Raw scores were collected for the cognitive, communicative, and motor subscales of the BSID-III-NL. Factor structure was evaluated with exploratory factor analysis and cluster analysis, and reliability of internal consistency was assessed using Cronbach's alpha coefficient for each subscale.

RESULTS

Content validity was endorsed by pediatricians and neuropsychologists in Suriname who participated in the administration of the BSID-III-NL. Construct validity was demonstrated through agreement of items from cluster analysis where at least 81.56% of all variability was explained by clustering with correct or incorrect responses and mean raw scores in subscales increased with age group. Cronbach's alpha coefficient was above 0.77 for all subscales.

CONCLUSIONS

This internationally validated developmental measure was found to be valid and reliable in assessing neurodevelopment of infants in Suriname.

Modulation of optical absorption in m-Fe1-xRuxS2 and exploring stability in new m-RuS2

A first-principle computational method has been used to investigate the effects of Ru dopants on the electronic and optical absorption properties of marcasite FeS2. In addition, we have also revealed a new marcasite phase in RuS2, unlike most studied pyrite structures. The new phase has fulfilled all the necessary criteria of structural stability and its practical existence. The transition pressure of 8 GPa drives the structural change from pyrite to orthorhombic phase in RuS2. From the thermodynamical calculation, we have reported the stability of new-phase under various ranges of applied pressure and temperature. Further, from the results of phonon dispersion calculated at Zero Point Energy, pyrite structure exhibits ground state stability and the marcasite phase has all modes of frequencies positive. The newly proposed phase is a semiconductor with a band gap comparable to its pyrite counterpart but vary in optical absorption by around 106 cm-1. The various Ru doped structures have also shown similar optical absorption spectra in the same order of magnitude. We have used crystal field theory to explain high optical absorption which is due to the involvement of different electronic states in formation of electronic and optical band gaps. Lӧwdin charge analysis is used over the customarily Mulliken charges to predict 89% of covalence in the compound. Our results indicate the importance of new phase to enhance the efficiency of photovoltaic materials for practical applications.

Paediatric Molecular Radiotherapy: Challenges and Opportunities

The common contemporary indications for paediatric molecular radiotherapy (pMRT) are differentiated thyroid cancer and neuroblastoma. It may also have value in neuroendocrine cancers, and it is being investigated in clinical trials for other diseases. pMRT is the prototypical biomarker-driven, precision therapy, with a unique mode of delivery and mechanism of action. It is safe and well tolerated, compared with other treatments. However, its full potential has not yet been achieved, and its wider use faces a number of challenges and obstacles. Paradoxically, the success of radioactive iodine as a curative treatment for metastatic thyroid cancer has led to a 'one size fits all' approach and limited academic enquiry into optimisation of the conventional treatment regimen, until very recently. Second, the specialised requirements for the delivery of pMRT are available in only a very limited number of centres. This limited capacity and geographical coverage results in reduced accessibility. With few enthusiastic advocates for this treatment modality, investment in research to improve treatments and broaden indications from both industry and national and charitable research funders has historically been suboptimal. Nonetheless, there is now an increasing interest in the opportunities offered by pMRT. Increased research funding has been allocated, and technical developments that will permit innovative approaches in pMRT are available for exploration. A new portfolio of clinical trials is being assembled. These studies should help to move at least some paediatric treatments from simply palliative use into potentially curative protocols. Therapeutic strategies require modification and optimisation to achieve this. The delivery should be personalised and tailored appropriately, with a comprehensive evaluation of tumour and organ-at-risk dosimetry, in alignment with the external beam model of radiotherapy. This article gives an overview of the current status of pMRT, indicating the barriers to progress and identifying ways in which these may be overcome.

Adequate antenatal care and ethnicity affect preterm birth in pregnant women living in the tropical rainforest of Suriname

Background

Adequate antenatal care (ANC) services are key for early identification of pregnancy related risk factors and maintaining women’s health during pregnancy. This study aimed to assess the influence of ANC provided by the Medical Mission Primary Health Care Suriname (MMPHCS) and of ethnicity on adverse birth outcomes in Tribal and Indigenous women living in Suriname’s remote tropical rainforest interior.

Method

From April 2017 to December 2018 eligible Tribal and Indigenous women with a singleton pregnancy that received ANC from MMPHCS were included in the study. Data on low birth weight (LBW < 2500 g), preterm birth (PTB < 37 weeks), low Apgar score (< 7 at 5 min), parity (≤1 vs. > 1) and antenatal visits utilization (≥8 vs. < 8) in 15 interior communities were retrospectively analyzed using descriptive statistics, crosstabs and Fisher’s exact tests.

Results

A total of 204 women were included, 100 (49%) were Tribal, mean age was 26 ± 7.2 years and 126 women (62%) had 8 or more ANC visits. One participant had a miscarriage; 22% had adverse birth outcomes: 16 (7.9%) LBW and 30 (14.8%) PTB; 7 women had a child with both PTB and LBW; 5 women had stillbirths. None of the newborns had low Apgar scores. Maternal age, ethnicity, ANC and parity were associated with PTB (χ² = 8,75, p = 0.003, χ² = 4,97, p = 0.025, χ² = 17,45, p < 0.001, χ² = 11,93, p < 0.001 respectively).

Conclusion

Despite an almost 100% study adherence over one fifth of women that received ANC in the interior of Suriname had adverse birth outcomes, in particular PTB and LBW. Younger nulliparous Indigenous women with less than the recommended 8 ANC visits had a higher risk for PTB. The rate of adverse birth outcomes highlights the need for further research to better assess factors influencing perinatal outcomes and to put strategies in place to improve perinatal outcomes. Exposure assessment of this sub-cohort and neurodevelopment testing of their children is ongoing and will further inform on potential adverse health effects associated with environmental exposures including heavy metals such as mercury and lead.

Delays and barriers to early treatment initiation for childhood tuberculosis in India

BACKGROUND: India accounts for 27% of global childhood tuberculosis (TB) burden. Understanding barriers to early diagnosis and treatment in children may improve care and outcomes.METHODS: A cross-sectional study was performed among 89 children initiated on anti-TB treatment from a public hospital in Pune during 2016, using a structured questionnaire and hospital records. Health care providers (HCPs) were defined as medical personnel consulted about the child's TB symptoms. Time-to-treatment initiation (TTI) was defined as the number of days between onset of TB symptoms and anti-TB treatment initiation. Based on Revised National TB Control Programme recommendations, delayed TTI was defined as >28 days.RESULTS: Sixty-seven (75%) of 89 enrolled children had significant TTI delays (median 51 days, interquartile range [IQR] 27-86). Sixty-six (74%) children visited 1-8 HCPs in the private sector before approaching the public sector. The median HCP delay was 28 days (IQR 10-75). Bacille Calmette-Guérin vaccination (aOR 10.96, P = 0.04) and loss of appetite (aOR 4.44, P = 0.04) were associated with delayed TTI.CONCLUSION: The majority of the children had TTI delays due to delays by HCPs in the private sector. Strengthening HCP competency in TB symptom screening and encouraging early referrals are crucial for rapid scaling up of early treatment initiation in childhood TB.

Study of half metallicity, structural and mechanical properties in inverse Heusler alloy Mn2ZnSi(1-x)Ge x and a superlattice

The electronic and magnetic properties of Mn₂ZnSi_(1−x)Ge_x (x = 0.0, 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, 0.875, and 1.0) inverse Heusler alloys and Mn₂ZnSi/Mn₂ZnGe superlattice have been investigated using first-principles calculations. All these alloys are stable in the fcc magnetic phase and satisfies the mechanical and thermal stability conditions as determined from the elastic constants and negative formation energy. The spin-polarized electronic band structures and the density of states indicate half-metallicity with 100% spin polarization at the Fermi energy level for x = 0.0, 0.125, 0.25, 0.50, and 1.0, with the integral values of the total magnetic moments per formula unit at their equilibrium lattice constants, following the Slater–Pauling rule. The electronic properties and the magnetic moments are mostly contributed by two Mn atoms and are coupled anti-parallel to each other, making them ferrimagnetic in nature. The presence of the half-metallic bandgap with an antiparallel alignment of Mn atoms makes these Heusler alloys a potential candidate for spintronic applications.

The electronic and magnetic properties of Mn₂ZnSi_(1−x)Ge_x (x = 0.0, 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, 0.875, and 1.0) inverse Heusler alloys and Mn₂ZnSi/Mn₂ZnGe superlattice have been investigated using first-principles calculations.

Flow-Pattern Details in an Aneurysm Model Using High-Speed 1000-Frames-per-Second Angiography

Traditional digital subtraction angiography provides rather limited evaluation of contrast flow dynamics when studying and treating intracranial brain aneurysms. A 1000-frames-per-second photon-counting x-ray detector was used to image detailed iodine-contrast flow patterns in an internal carotid artery aneurysm of a 3D-printed vascular phantom. High-speed imaging revealed differences in vortex and inflow patterns with and without a Pipeline Embolization Device flow diverter in more detail and clarity than could be seen in standard pulsed angiography. Improved temporal imaging has the potential to impact the outcomes of endovascular interventions by allowing clinicians to better understand and act on flow dynamics in real-time.

Electronic and Magnetic Properties of Fe Atomic Chain and Fe Atomic Plane: Anab initioStudy

The electronic and magnetic properties of Fe atomic wire and atomic plane have been theoretically investigated from full potential linearized augmented plane wave (FPLAPW) method within a frame work of density functional theory (DFT). This work is based on the comparative study of number of Fe nanochains with infinite length and infinitely spread Fe nanosheet. A most commonly adopted GGA approximation is used for electron exchange correlation. In our calculation, the property of Fe-chain is predicted to be magnetic metal with the presence of deep valley (in Spin-up DOS) and a peak (in Spin-down DOS) at Fermi level ([Formula: see text]) shows the antisymmetric DOS. The presence of antisymmetric DOS is a signature of exchange splitting between the degenerated d-states. The splitting between t[Formula: see text] states is very prominent in Fe-chain which enhances the magnetic moment. The magnetic moment decreases with the increase in number of Fe-chains.

Initial investigations of a special high-definition (Hi-Def) zoom capability in a new detector system for neuro-interventional procedures

Real-time visualization of fine details ranging to 100 um or less in neuro-vascular imaging guided interventions is important. A separate high-resolution detector mounted on a standard flat panel detector (FPD) was previously reported. This device had to be rotated mechanically into position over the FPD for high resolution imaging. Now, the new detector reported here has a high definition (Hi-Def) zoom capability along with the FPD built into one unified housing. The new detector enables rapid switching, by the operator between Hi-Def and FPD modes. Standard physical metrics comparing the new Hi-Def modes with those of the FPD are reported, demonstrating improved imaging resolution and noise capability at patient doses similar to those used for the FPD. Semi-quantitative subjective studies involving qualitative clinician feedback on images of interventional devices such as a Pipeline Embolization Device (PED) acquired in both Hi-Def and FPD modes are presented. The PED is deployed in a patient specific 3D printed neuro-vascular phantom embedded inside realistic bone and with tissue attenuating material. Field-of-view (FOV), exposure and magnification were kept constant for FPD and Hi-Def modes. Static image comparisons of the same view of the PED within the phantom were rated by expert interventionalists who chose from the following ratings: Similar, Better, or Superior. Generally, the Hi-Def zoomed images were much preferred over the FPD, indicating the potential to improve endovascular procedures and hence outcomes using such a Hi-Def feature.

Spectroscopy with a CdTe-based photon-counting imaging detector (PCD) having charge sharing correction capability

The spectroscopic capabilities of a newly upgraded version of a prototype imaging photon counting detector (PCD) was investigated. The XCounter Actaeon has four acquisition modes in which signal processing is varied including one mode having a charge sharing correction so that neighboring pixels that share a detected event will not be erroneously counted twice, hence it is designated the Anti-Coincidence Circuit On or ACC On mode. Since this CdTe-based direct conversion PCD has 100 μm pixels, such charge sharing may frequently occur for typical medical x-ray energies. Each pixel of this PCD has two scalers and two energy discriminators that enable counting without instrumentation noise of events above each threshold level; hence, a spectrum can be obtained by sequentially moving the thresholds of both discriminators. It became evident from the spectra for the various acquisition modes that only those obtained with the charge sharing correction enabled, compared favorably with theoretically predicted spectra. After verifying the energy calibration using the mono-energetic emissions from an Am-241 source, spectra at various kVps from a standard medical x-ray generator were obtained. The spectra generated by ACC On mode for 70 kVp and 110 kVp were the closest match to the theoretical spectra generated by SpekCal. For dual energy applications, ACC On mode with charge sharing correction circuitry would be the best choice among various acquisition modes. Also investigated was the dual energy imaging capability of the Actaeon PCD with ACC On mode to separate Aluminum and Iodine while imaging an artery stenosis phantom.

A Review of the Parenteral Nutrition Supply Service in an Irish Neonatal Unit

Background Neonatal Intensive Care (NICU) patients have individual nutritional requirements often requiring Patient Specific Parenteral Nutrition (PSPN). From October 2015, the national PSPN compounding service availability changed from 7 days per week service to 5 days per week (i.e. no weekend and limited bank holiday ordering available). The aim of this study was to examine the introduction of a 5 day only PSPN supply on neonatal patient parenteral nutrition availability in a tertiary NICU. Methods We performed a prospective assessment of the provision of a 5 day rather than 7 day ordering of PSPN over a one month period (June 2017). Results Fifteen neonatal patients received a cumulative 89 days of PN during June 2017. 10 (66%) patients received PSPN during this time period. There was same day availability of PSPN in 62 of 89 days of PN (69%). Conclusion Thorough education and training will help prescribers to make appropriate PSPN ordering decisions. Improvements to available stock bags may reduce the amount of PSPN that is required but a 7 day PSPN ordering service would improve efficient provision of clinically indicated PSPN to premature infants in NICU in Ireland.

The Triangular Sign, a Useful Diagnostic Marker for Biliary Atresia: A Case Series of Three Irish Infants

Background The triangular cord (TC) sign is the appearance of a triangular shaped echogenic density visualised immediately cranial to the portal vein bifurcation on ultrasonographic examination. Several studies have reported that this ultrasonographic sign is a reliable and helpful marker in identifying Biliary Atresia (BA). Aims To report the identification of the TC sign in three infants with BA in the Rotunda Hospital, Dublin. Methods A retrospective chart review was performed to evaluate the clinical presentation and imaging of the three patients with positive TC sign and BA. Discussion Timely, accurate diagnosis of BA is essential to minimise morbidity and optimise patient outcome. The TC is a valuable ultrasonographic sign to aid early diagnosis of BA.

Loss to follow-up and mortality among HIV-infected adolescents receiving antiretroviral therapy in Pune, India

OBJECTIVES

India has the highest number of HIV-infected adolescents in Asia, but little is known about their treatment outcomes. We assessed rates and factors associated with loss to follow-up (LTFU) and mortality among Indian adolescents.

METHODS

The analysis included adolescents (10-19 years old) starting antiretroviral therapy (ART) between 2005 and 2014 at BJ Government Medical College, Pune, India. LTFU was defined as missing more than three consecutive monthly visits. The competing-risks method was used to calculate subdistribution hazard ratios (SHRs) of predictors for LTFU, with death as the competing risk. Cox proportional hazard models were used to identify predictors of mortality.

RESULTS

Of 717 adolescents starting ART, 402 with complete data were included in the analysis. Of these, 61% were male and 80% were perinatally infected, and the median baseline CD4 count was 174 cells/μL. LTFU and mortality rates were 4.4 and 4.9/100-person years, respectively. Cumulative LTFU incidence increased from 6% to 15% over 6 years. Age ≥ 15 years [adjusted SHR (aSHR) 2.44; 95% confidence interval (CI) 1.18-5.02] was a risk factor for LTFU. Cumulative mortality increased from 9.5% to 17.9% over 6 years. World Health Organization (WHO) stages III and IV [adjusted hazard ratio (aHR) 2.26; 95% CI: 1.14-4.48] and an increase in CD4 count by 100 cells/μL (aHR: 0.59; 95% CI: 0.43-0.83) were associated with mortality.

CONCLUSIONS

A third of adolescents had been lost to follow-up or died by follow-up year 6. Older age was a risk factor for LTFU and advanced clinical disease for death. Strategies to improve retention counselling for older adolescents and closer clinical monitoring of all adolescents must be considered.

Gantry rotational motion-induced blur in cone-beam computed tomography

As neuro-endovascular image-guided interventions (EIGIs) make use of higher resolution detectors, gantry rotational motion-induced blur becomes more noticeable in acquired projections as well as reconstructed images by reducing the visibility of vascular and device features whose visualization could be critical in the treatment of vascular pathology. Motion-induced blur in projections views is a function of an object's position in the field-of-view (FOV), gantry rotational speed, and frame capture or exposure time. In this work different frame rates were used to investigate the effects of blurring from individual projections on the reconstructed image. To test the effects of these parameters on reconstructed images, a regular pattern phantom of small objects was simulated and projection views were generated at various different frame rates for a given simulated rotational velocity. The reconstruction was made using a linear interpolation of filtered backprojections. Images reconstructed from lower frame rates showed significant blurring in the azimuthal direction, increasingly worse towards the periphery of the image. However, those reconstructed from higher frame rates showed significantly less blur throughout the entire FOV. While lower frame rates could be used with slower gantry speeds this would increase the risk of voluntary or involuntary patient motion contributing to blur over the entire FOV. A high frame rate used with high gantry speeds could reliable provide images without gantry-motion blur while reducing the risk of patient-motion blur. Frame rates exceeding 2000 fps available with photon counting detectors such as the X-counter Actaeon¹ are available.

Evaluation of a new photon-counting imaging detector (PCD) with various acquisition modes

The prospect of improved low noise, high speed, and dual-energy imaging that may be associated with the use of photon-counting imaging detectors (PCD) has motivated this evaluation of a newly upgraded version of a prototype PCD. The XCounter Actaeon was evaluated in its four acquisition modes each based upon varying signal processing firmware including a mode with charge sharing correction that enables neighboring pixels that share the energy from one incident x-ray photon detection to be counted only once at the proper summed energy in the pixel with the largest charge deposition. Since this PCD is a CdTe-based direct detector with 100 μm pixels, such charge sharing for typical medical x-ray energy photons may occur frequently and must be corrected to achieve more accurate counts. This charge sharing correction is achieved with an Anti-Coincidence Circuit (ACC) which prevents double pixel counting from one event as well as prevents counting from either event if they are below a preset threshold. Various physical parameters of the PCD were evaluated including linearity, sensitivity, pulse pile-up effects, dark noise, spatial resolution, noise power spectrum, and detective quantum efficiency.

Major postoperative complications after pancreatic resection for P-NETS are not associated to earlier recurrence

BACKGROUND

The oncological impact of surgical complications has been studied in visceral and pancreatic cancer.

AIM

To investigate the impact of complications on tumour recurrence after resections for pancreatic neuroendocrine tumours.

METHODS

We have retrospectively analysed 105 consecutive resections performed at the Royal Free London Hospital from 1998 to 2014, and studied the long-term outcome of nil-minor (<3) versus major (≥3) Clavien-Dindo complications (CD) on disease-free (DFS) and overall survival (OS).

RESULTS

The series accounted for 41 (39%) pancreaticoduodenectomies, two (1.9%) central, 48 (45.7%) distal pancreatectomies, eight (7.6%) enucleations, four (3.8%) total pancreatectomies. Sixteen (15.2%) were extended to adjacent organs, 13 (12.3%) to minor liver resections. Postoperative complications presented in 43 (40.1%) patients; CD grade 1 or 2 in 23 (21.9%), grades ≥3 in 20 (19%). Among 25 (23.8%) pancreatic fistulas, 14 (13.3%) were grades B or C. Thirty-four (32.4%) patients developed exocrine, and 31 (29.5%) endocrine insufficiency. Seven patients died during a median 27 (0-175) months follow up. Thirty-day mortality was 0.9%. OS was 94.1% at 5 years. Thirty tumours recurred within 11.7 (0.8-141.5) months. DFS was 44% at 5 years. At univariate analysis, high-grade complications were not associated with shorter DFS (p = 0.744). At multivariate analysis, no parameter was independent predictor for DFS or OS. The comparison of nil-minor versus major complications showed no DFS difference (p = 0.253).

CONCLUSION

From our series, major complications after P-NETs resection are not associated to different disease recurrence; hence do not require different follow up or adjuvant regimens.

Prevalence of depression and anxiety disorder in cancer patients: An institutional experience

AIM

This study aimed to screen the patients with various malignancies for the presence of depressive disorders and anxiety disorder using standardized rating scales.

MATERIALS AND METHODS

Five hundred and thirty-four (n = 534) patients attending the radiotherapy outpatient services completed the Patient Health Questionnaire-9 and Generalized Anxiety Disorder-7 (GAD-7) Questionnaire.

RESULTS

About half (n = 248; 46.4%) of the patients had psychiatric morbidity either in the form of depressive disorder or in the form of GAD. Higher stage of malignancy (from early, advanced to metastasis) was associated with higher prevalence of depressive disorder and GAD. The presence of psychiatric morbidity, especially anxiety disorder, was associated with being from low socioeconomic status.

CONCLUSION

The present study suggests that psychiatric morbidity in the form of depressive and anxiety disorders is very common among patients with malignancies. Accordingly, there is a need for close liaison between oncologists and mental health professionals to improve the outcome of patients with various malignancies.

Focal spot size reduction using asymmetric collimation to enable reduced anode angles with a conventional angiographic x-ray tube for use with high resolution detectors

The high-resolution requirements for neuro-endovascular image-guided interventions (EIGIs) necessitate the use of a small focal-spot size; however, the maximum tube output limits for such small focal-spot sizes may not enable sufficient x-ray fluence after attenuation through the human head to support the desired image quality. This may necessitate the use of a larger focal spot, thus contributing to the overall reduction in resolution. A method for creating a higher-output small effective focal spot based on the line-focus principle has been demonstrated and characterized. By tilting the C-arm gantry, the anode-side of the x-ray field-of-view is accessible using a detector placed off-axis. This tilted central axis diminishes the resultant focal spot size in the anode-cathode direction by the tangent of the effective anode angle, allowing a medium focal spot to be used in place of a small focal spot with minimal losses in resolution but with increased tube output. Images were acquired of two different objects at the central axis, and with the C-arm tilted away from the central axis at 1° increments from 0°-7°. With standard collimation settings, only 6° was accessible, but using asymmetric extended collimation a maximum of 7° was accessed for enhanced comparisons. All objects were positioned perpendicular to the anode-cathode direction and images were compared qualitatively. The increasing advantage of the off-axis focal spots was quantitatively evidenced at each subsequent angle using the Generalized Measured-Relative Object Detectability metric (GM-ROD). This anode-tilt method is a simple and robust way of increasing tube output for a small field-of-view detector without diminishing the overall apparent resolution for neuro-EIGIs.

A CMOS-based high resolution fluoroscope (HRF) detector prototype with 49.5 μm pixels for use in endovascular image guided interventions (EIGI)

X-ray detectors to meet the high-resolution requirements for endovascular image-guided interventions (EIGIs) are being developed and evaluated. A new 49.5-micron pixel prototype detector is being investigated and compared to the current suite of high-resolution fluoroscopic (HRF) detectors. This detector featuring a 300-micron thick CsI(Tl) scintillator, and low electronic noise CMOS readout is designated the HRF-CMOS₅₀. To compare the abilities of this detector with other existing high resolution detectors, a standard performance metric analysis was applied, including the determination of the modulation transfer function (MTF), noise power spectra (NPS), noise equivalent quanta (NEQ), and detective quantum efficiency (DQE) for a range of energies and exposure levels. The advantage of the smaller pixel size and reduced blurring due to the thin phosphor was exemplified when the MTF of the HRF-CMOS₅₀ was compared to the other high resolution detectors, which utilize larger pixels, other optical designs or thicker scintillators. However, the thinner scintillator has the disadvantage of a lower quantum detective efficiency (QDE) for higher diagnostic x-ray energies. The performance of the detector as part of an imaging chain was examined by employing the generalized metrics GMTF, GNEQ, and GDQE, taking standard focal spot size and clinical imaging parameters into consideration. As expected, the disparaging effects of focal spot unsharpness, exacerbated by increasing magnification, degraded the higher-frequency performance of the HRF-CMOS₅₀, while increasing scatter fraction diminished low-frequency performance. Nevertheless, the HRF-CMOS₅₀ brings improved resolution capabilities for EIGIs, but would require increased sensitivity and dynamic range for future clinical application.

Cardiac cephalgia: a diagnostic headache

A 73-year-old man presented with a 6-month history of exertional headaches. Exercise tolerance test demonstrated progressive ischaemic changes concomitant with worsening headache. Cardiac cephalgia was diagnosed and his symptoms resolved after coronary artery bypass surgery. Cardiac cephalgia may occasionally present as exertional headache without chest symptoms.

Prevalence and Predictors of Non-Alcoholic Fatty Liver Disease in Morbidly Obese South Indian Patients Undergoing Bariatric Surgery

BACKGROUND

Numerous studies worldwide have identified a high prevalence of non-alcoholic fatty liver disease (NAFLD) among morbidly obese subjects. Several predictors have been found to be associated with NAFLD and its histological high-risk components. Similar data from India is lacking. We aimed to determine the prevalence and the predictors of NAFLD and its histological high-risk components in a cohort of Indians with morbid obesity undergoing bariatric surgery. Safety of a routine intraoperative liver biopsy was also assessed.

METHODS

There were 134 morbidly obese patients who underwent bariatric surgery with concomitant liver biopsy. These were assessed for NAFLD and its histological high-risk components. Clinical, biochemical, and histological features were evaluated, and predictors of NAFLD, non-alcoholic steatohepatitis (NASH), fibrosis, and advanced fibrosis were identified.

RESULTS

Mean BMI was 44.66 ± 9.81. Eighty-eight (65.7 %) showed NAFLD. Forty-five (33.6 %) showed NASH and 42 (31.3 %) showed fibrosis both not mutually exclusive. Nineteen (14.1 %) showed advanced fibrosis. Higher alanine aminotransferase (ALT) independently predicted NAFLD and was significantly associated with NASH and fibrosis. Type 2 diabetes mellitus (T2DM) and the metabolic syndrome were significantly associated with fibrosis. Systemic hypertension (HT) independently predicted NASH and fibrosis. There were no intraoperative or postoperative complications related to the liver biopsy.

CONCLUSIONS

NAFLD has a high prevalence among morbidly obese patients. Elevated ALT, HT, T2DM, and the metabolic syndrome are predictors for NAFLD and its high-risk histological components. Routine intraoperative liver biopsy is safe in morbidly obese undergoing bariatric surgery for diagnosing NAFLD.

Scatter estimation and removal of anti-scatter grid-line artifacts from anthropomorphic head phantom images taken with a high resolution image detector

In radiography, one of the best methods to eliminate image-degrading scatter radiation is the use of anti-scatter grids. However, with high-resolution dynamic imaging detectors, stationary anti-scatter grids can leave grid-line shadows and moiré patterns on the image, depending upon the line density of the grid and the sampling frequency of the x-ray detector. Such artifacts degrade the image quality and may mask small but important details such as small vessels and interventional device features. Appearance of these artifacts becomes increasingly severe as the detector spatial resolution is improved. We have previously demonstrated that, to remove these artifacts by dividing out a reference grid image, one must first subtract the residual scatter that penetrates the grid; however, for objects with anatomic structure, scatter varies throughout the FOV and a spatially differing amount of scatter must be subtracted. In this study, a standard stationary Smit-Rontgen X-ray grid (line density - 70 lines/cm, grid ratio - 13:1) was used with a high-resolution CMOS detector, the Dexela 1207 (pixel size - 75 micron) to image anthropomorphic head phantoms. For a 15 × 15cm FOV, scatter profiles of the anthropomorphic head phantoms were estimated then iteratively modified to minimize the structured noise due to the varying grid-line artifacts across the FOV. Images of the anthropomorphic head phantoms taken with the grid, before and after the corrections, were compared demonstrating almost total elimination of the artifact over the full FOV. Hence, with proper computational tools, anti-scatter grid artifacts can be corrected, even during dynamic sequences.

Quantitative comparison using Generalized Relative Object Detectability (G-ROD) metrics of an amorphous selenium detector with high resolution Microangiographic Fluoroscopes (MAF) and standard flat panel detectors (FPD)

A novel amorphous selenium (a-Se) direct detector with CMOS readout has been designed, and relative detector performance investigated. The detector features include a 25μm pixel pitch, and 1000μm thick a-Se layer operating at 10V/μm bias field. A simulated detector DQE was determined, and used in comparative calculations of the Relative Object Detectability (ROD) family of prewhitening matched-filter (PWMF) observer and non-prewhitening matched filter (NPWMF) observer model metrics to gauge a-Se detector performance against existing high resolution micro-angiographic fluoroscopic (MAF) detectors and a standard flat panel detector (FPD). The PWMF-ROD or ROD metric compares two x-ray imaging detectors in their relative abilities in imaging a given object by taking the integral over spatial frequencies of the Fourier transform of the detector DQE weighted by an object function, divided by the comparable integral for a different detector. The generalized-ROD (G-ROD) metric incorporates clinically relevant parameters (focal-spot size, magnification, and scatter) to show the degradation in imaging performance for detectors that are part of an imaging chain. Preliminary ROD calculations using simulated spheres as the object predicted superior imaging performance by the a-Se detector as compared to existing detectors. New PWMF-G-ROD and NPWMF-G-ROD results still indicate better performance by the a-Se detector in an imaging chain over all sphere sizes for various focal spot sizes and magnifications, although a-Se performance advantages were degraded by focal spot blurring. Nevertheless, the a-Se technology has great potential to provide breakthrough abilities such as visualization of fine details including of neuro-vascular perforator vessels and of small vascular devices.

Targeting Bone Marrow to Potentiate the Anti-Tumor Effect of Tyrosine Kinase Inhibitor in Preclinical Rat Model of Human Glioblastoma

Antiangiogenic agents caused paradoxical increase in pro-growth and pro-angiogenic factors and caused tumor growth in glioblastoma (GBM). It is hypothesized that paradoxical increase in pro-angiogenic factors would mobilize Bone Marrow Derived Cells (BMDCs) to the treated tumor and cause refractory tumor growth. The purposes of the studies were to determine whether whole body irradiation (WBIR) or a CXCR4 antagonist (AMD3100) will potentiate the effect of vatalanib (a VEGFR2 tyrosine kinase inhibitor) and prevent the refractory growth of GBM. Human GBM were grown orthotopically in three groups of rats (control, pretreated with WBIR and AMD3100) and randomly selected for vehicle or vatalanib treatments for 2 weeks. Then all animals underwent Magnetic Resonance Imaging (MRI) followed by euthanasia and histochemical analysis. Tumor volume and different vascular parameters (plasma volume (v_p), forward transfer constant (K^trans), back flow constant (k_ep), extravascular extracellular space volume (v_e) were determined from MRI. In control group, vatalanib treatment increased the tumor growth significantly compared to that of vehicle treatment but by preventing the mobilization of BMDCs and interaction of CXCR4-SDF-1 using WBIR and ADM3100, respectively, paradoxical growth of tumor was controlled. Pretreatment with WBIR or AMD3100 also decreased tumor cell migration, despite the fact that ADM3100 increased the accumulation of M1 and M2 macrophages in the tumors. Vatalanib also increased K^trans and v_e in control animals but both of the vascular parameters were decreased when the animals were pretreated with WBIR and AMD3100. In conclusion, depleting bone marrow cells or CXCR4 interaction can potentiate the effect of vatalanib.

Correction: Study of the enhanced electronic and thermoelectric (TE) properties of ZrxHf1−x−yTayNiSn: a first principles study

Correction for ‘Study of the enhanced electronic and thermoelectric (TE) properties of Zr_xHf_1−x−yTa_yNiSn: a first principles study’ by D. P. Rai et al., RSC Adv., 2015, 5, 95353–95359.

Successful return to high-level sports following early surgical repair of combined adductor complex and rectus abdominis avulsion

Hip and groin injuries are common in athletes who take part in high level sports. Adductor muscle tendon injuries represent a small but important number of these injuries. Avulsion of the tendons attached to the symphysis pubis has previously been described: these can be managed both operatively and non-operatively. We describe an uncommon variant of this injury, namely complete avulsion of the adductor sleeve complex: this includes adductor longus, pectineus and rectus abdominis. We go on to describe a surgical technique which promotes a full return to the pre-injury level of sporting activity.

Over a period of ten years, 15 high-level athletes with an MRI-confirmed acute adductor complex avulsion injury (six to 34 days old) underwent surgical repair. The operative procedure consisted of anatomical re-attachment of the avulsed tissues in each case and mesh reinforcement of the posterior inguinal wall in seven patients. All underwent a standardised rehabilitation programme, which was then individualised to be sport-specific.

One patient developed a superficial wound infection, which was successfully treated with antibiotics. Of the 15 patients, four complained of transient local numbness which resolved in all cases. All patients (including seven elite athletes) returned to their previous level of participation in sport.

Cite this article: Bone Joint J 2015;97-B:1488–92.