Fast pseudo-CT synthesis from MRI T1-weighted images using a patch-based approach

MRI-based bone segmentation is a challenging task because bone tissue and air both present low signal intensity on MR images, making it difficult to accurately delimit the bone boundaries. However, estimating bone from MRI images may allow decreasing patient ionization by removing the need of patient-specific CT acquisition in several applications. In this work, we propose a fast GPU-based pseudo-CT generation from a patient-specific MRI T1-weighted image using a group-wise patch-based approach and a limited MRI and CT atlas dictionary. For every voxel in the input MR image, we compute the similarity of the patch containing that voxel with the patches of all MR images in the database, which lie in a certain anatomical neighborhood. The pseudo-CT is obtained as a local weighted linear combination of the CT values of the corresponding patches. The algorithm was implemented in a GPU. The use of patch-based techniques allows a fast and accurate estimation of the pseudo-CT from MR T1-weighted images, with a similar accuracy as the patient-specific CT. The experimental normalized cross correlation reaches 0.9324±0.0048 for an atlas with 10 datasets. The high NCC values indicate how our method can accurately approximate the patient-specific CT. The GPU implementation led to a substantial decrease in computational time making the approach suitable for real applications

Sequence variant at 8q24.21 associates with sciatica caused by lumbar disc herniation.

Efst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked FilesLumbar disc herniation (LDH) is common and often debilitating. Microdiscectomy of herniated lumbar discs (LDHsurg) is performed on the most severe cases to resolve the resulting sciatica. Here we perform a genome-wide association study on 4,748 LDHsurg cases and 282,590 population controls and discover 37 highly correlated markers associating with LDHsurg at 8q24.21 (between CCDC26 and GSDMC), represented by rs6651255[C] (OR=0.81; P=5.6 × 10(-12)) with a stronger effect among younger patients than older. As rs6651255[C] also associates with height, we performed a Mendelian randomization analysis using height polygenic risk scores as instruments to estimate the effect of height on LDHsurg risk, and found that the marker's association with LDHsurg is much greater than predicted by its effect on height. In light of presented findings, we speculate that the effect of rs6651255 on LDHsurg is driven by susceptibility to developing severe and persistent sciatica upon LDH.European Commission National Institutes of Healt

Randomized Clinical Trials and Observational Tribulations: Providing Clinical Evidence for Personalized Surgical Pain Management Care Models

Proving clinical superiority of personalized care models in interventional and surgical pain management is challenging. The apparent difficulties may arise from the inability to standardize complex surgical procedures that often involve multiple steps. Ensuring the surgery is performed the same way every time is nearly impossible. Confounding factors, such as the variability of the patient population and selection bias regarding comorbidities and anatomical variations are also difficult to control for. Small sample sizes in study groups comparing iterations of a surgical protocol may amplify bias. It is essentially impossible to conceal the surgical treatment from the surgeon and the operating team. Restrictive inclusion and exclusion criteria may distort the study population to no longer reflect patients seen in daily practice. Hindsight bias is introduced by the inability to effectively blind patient group allocation, which affects clinical result interpretation, particularly if the outcome is already known to the investigators when the outcome analysis is performed (often a long time after the intervention). Randomization is equally problematic, as many patients want to avoid being randomly assigned to a study group, particularly if they perceive their surgeon to be unsure of which treatment will likely render the best clinical outcome for them. Ethical concerns may also exist if the study involves additional and unnecessary risks. Lastly, surgical trials are costly, especially if the tested interventions are complex and require long-term follow-up to assess their benefit. Traditional clinical testing of personalized surgical pain management treatments may be more challenging because individualized solutions tailored to each patient’s pain generator can vary extensively. However, high-grade evidence is needed to prompt a protocol change and break with traditional image-based criteria for treatment. In this article, the authors review issues in surgical trials and offer practical solutions

The Changing Environment in Postgraduate Education in Orthopedic Surgery and Neurosurgery and Its Impact on Technology-Driven Targeted Interventional and Surgical Pain Management : Perspectives from Europe, Latin America, Asia, and The United States

Personalized care models are dominating modern medicine. These models are rooted in teaching future physicians the skill set to keep up with innovation. In orthopedic surgery and neurosurgery, education is increasingly influenced by augmented reality, simulation, navigation, robotics, and in some cases, artificial intelligence. The postpandemic learning environment has also changed, emphasizing online learning and skill- and competency-based teaching models incorporating clinical and bench-top research. Attempts to improve work–life balance and minimize physician burnout have led to work-hour restrictions in postgraduate training programs. These restrictions have made it particularly challenging for orthopedic and neurosurgery residents to acquire the knowledge and skill set to meet the requirements for certification. The fast-paced flow of information and the rapid implementation of innovation require higher efficiencies in the modern postgraduate training environment. However, what is taught typically lags several years behind. Examples include minimally invasive tissue-sparing techniques through tubular small-bladed retractor systems, robotic and navigation, endoscopic, patient-specific implants made possible by advances in imaging technology and 3D printing, and regenerative strategies. Currently, the traditional roles of mentee and mentor are being redefined. The future orthopedic surgeons and neurosurgeons involved in personalized surgical pain management will need to be versed in several disciplines ranging from bioengineering, basic research, computer, social and health sciences, clinical study, trial design, public health policy development, and economic accountability. Solutions to the fast-paced innovation cycle in orthopedic surgery and neurosurgery include adaptive learning skills to seize opportunities for innovation with execution and implementation by facilitating translational research and clinical program development across traditional boundaries between clinical and nonclinical specialties. Preparing the future generation of surgeons to have the aptitude to keep up with the rapid technological advances is challenging for postgraduate residency programs and accreditation agencies. However, implementing clinical protocol change when the entrepreneur–investigator surgeon substantiates it with high-grade clinical evidence is at the heart of personalized surgical pain management

Rare SLC13A1 variants associate with intervertebral disc disorder highlighting role of sulfate in disc pathology.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked DownloadBack pain is a common and debilitating disorder with largely unknown underlying biology. Here we report a genome-wide association study of back pain using diagnoses assigned in clinical practice; dorsalgia (119,100 cases, 909,847 controls) and intervertebral disc disorder (IDD) (58,854 cases, 922,958 controls). We identify 41 variants at 33 loci. The most significant association (ORIDD = 0.92, P = 1.6 × 10-39; ORdorsalgia = 0.92, P = 7.2 × 10-15) is with a 3'UTR variant (rs1871452-T) in CHST3, encoding a sulfotransferase enzyme expressed in intervertebral discs. The largest effects on IDD are conferred by rare (MAF = 0.07 - 0.32%) loss-of-function (LoF) variants in SLC13A1, encoding a sodium-sulfate co-transporter (LoF burden OR = 1.44, P = 3.1 × 10-11); variants that also associate with reduced serum sulfate. Genes implicated by this study are involved in cartilage and bone biology, as well as neurological and inflammatory processes.European Commission European Commission Joint Research Centre Novo Nordisk Foundation Novocure Limite

Gray mold caused by Botrytis cinerea limits grape production in Chile

Gray mold (GM) caused by Botrytis cinerea is a major disease of grapes (Vitis vinifera) that substantially reduces the yield and quality of grape production in temperate and humid regions of the world. B. cinerea is a necrotrophic fungus that attacks the non-lignified aerial organs of grapes; in particular, berries are highly susceptible during ripening. The polycyclic nature and exponential progress exhibited by GM at the beginning of the its epidemic, as well as the abundant inoculum production, the high dissemination efficiency, the wide host range and the high genetic variability of B. cinerea, explain the difficulties encountered in attempting to control GM. At present, integrated disease management, including cultural and chemical control, is the main control strategy. These control measures can be used to reduce the initial inoculum or to lower the disease infection rate. However, control measures that reduce the infection rate are the most effective means of controlling GM. Important progress toward understanding the complexity of the biology and epidemiology of this pathogen has occurred in recent decades. This has allowed the improvement and development of more effective and sustainable control strategies against B. cinerea. This review article provides a recent update regarding grape GM, with special emphasis on Chilean production conditions.La pudrición gris (PG) causada por Botrytis cinerea, es una de las principales enfermedades de la vid (Vitis vinifera) que limita la producción y reduce los rendimientos y la calidad de la fruta en zonas templadas y húmedas a nivel mundial. B. cinerea es un hongo necrótrofo que ataca órganos aéreos no lignificados de la vid, siendo las bayas altamente susceptibles durante la maduración. La naturaleza policíclica y el desarrollo exponencial de las epidemias de PG, junto con la abundancia de inóculo, la eficiente dispersión más el amplio rango de hospederos y gran variabilidad genética que presenta B. cinerea, explican las dificultades para lograr un control satisfactorio. Ante lo cual se hace necesario realizar una estrategia de control integrado que combine medias de control cultural y químico. Estas medidas pueden estar orientadas a reducir el inoculo inicial o la tasa de progreso de la enfermedad, siendo las medidas de control destinadas a reducir la tasa de progreso las que más aporta al control de PG. En las últimas décadas se han producido importantes progresos en el conocimiento de la compleja biología de este patógeno y de los aspectos epidemiológicos de la PG. Esto ha permitido mejorar las estrategias de control logrando alternativas más efectivas y sustentables. En este artículo se revisan los aportes científicos recientes realizados en relación con la PG de la vid, teniendo especial énfasis en la situación del viñedo chileno

Operative Mortality After Arthroplasty for Femoral Neck Fracture and Hospital Volume

Background: The purpose of the present study is to use a statewide, population-based data set to identify mortality rates at 30-day and 1-year postoperatively following total hip arthroplasty (THA) and hemiarthroplasty (HA) for displaced femoral neck fractures. The secondary aim of the study is to determine whether arthroplasty volume confers a protective effect on the mortality rate following femoral neck fracture treatment. Methods: New York’s Statewide Planning and Research Cooperative System was used to identify 45 749 patients older than 60 years of age with a discharge diagnosis of femoral neck fracture undergoing THA or HA from 2000 through 2010. Comorbidities were identified using the Charlson comorbidity index. Mortality risk was modeled using Cox proportional hazards models while controlling for demographic and comorbid characteristics. High-volume THA centers were defined as those in the top quartile of arthroplasty volume, while low-volume centers were defined as the bottom quartile. Results: Patients undergoing THA for femoral neck fracture rather than HA were younger (79 vs 83 years, P < .001), more likely to have rheumatoid disease, and less likely to have heart disease, dementia, cancer, or diabetes (all P < .05). Thirty-day mortality after HA was higher (8.4% vs 5.7%; P < .001) as was 1-year mortality (25.9% vs 17.8%; P < .001). After controlling for age, gender, ethnicity, and comorbidities, risk of mortality following THA was 21% lower (hazard ratio [HR] 0.79; P = .003) at 30 days and 22% lower (HR 0.78; P < .001) at 1 year than HA. Patients undergoing THA at high-volume arthroplasty centers had improved 1-year mortality when compared to those undergoing THA at low-volume hospitals (HR 0.55; P = .008). Conclusions: Based on this large, population-based study, there is no basis to assume THA carries a greater mortality risk after hip fracture than does standard HA, even when accounting for institutional volume of hip arthroplasty

Update on pediatric gastroparesis: A review of the published literature and recommendations for future research

Background Due to scarcity of scientific literature on pediatric gastroparesis, there is a need to summarize current evidence and identify areas requiring further research. The aim of this study was to provide an evidence‐based review of the available literature on the prevalence, pathogenesis, clinical presentation, diagnosis, treatment, and outcomes of pediatric gastroparesis. Methods A search of the literature was performed using the Preferred Reporting Items for Systematic Reviews and Meta‐analyses guidelines with the following databases: PubMed, EMBASE, Cochrane Database of Systematic Reviews, Database of s of Reviews of Effects, Cochrane Central Register of Controlled Trials, and Web of Science. Two independent reviewers screened s for eligibility. Key Results Our search yielded 1085 original publications, 135 of which met inclusion criteria. Most articles were of retrospective study design. Only 12 randomized controlled trials were identified, all of which were in infants. The prevalence of pediatric gastroparesis is unknown. Gastroparesis may be suspected based on clinical symptoms although these are often non‐specific. The 4‐hour nuclear scintigraphy scan remains gold standard for diagnosis despite lack of pediatric normative comparison data. Therapeutic approaches include dietary modifications, prokinetic drugs, and postpyloric enteral tube feeds. For refractory cases, intrapyloric botulinum toxin and surgical interventions such as gastric electrical stimulation may be warranted. Most interventions still lack rigorous supportive data. Conclusions Diagnosis and treatment of pediatric gastroparesis are challenging due to paucity of published evidence. Larger and more rigorous clinical trials are necessary to improve outcomes. Overview of suggested, step‐wise approach to pediatric gastroparesis

Serum amyloid A renal amyloidosis in a chronic subcutaneous ("skin popping") heroin user

Background: Systemic AA amyloidosis is a long-term complication of several chronic inflammatory disorders. Organ damage results from the extracellular deposition of proteolytic fragments of the acute-phase reactant serum amyloid A (SAA) as amyloid fibrils. Drug users that inject drug by a subcutaneous route ("skin popping") have a higher chance of developing secondary amyloidosis. The kidneys, liver, and spleen are the main target organs of AA amyloid deposits. More than 90% of patients with renal amyloidosis will present with proteinuria, nephrotic syndrome, or renal dysfunction. Case presentation: A 37 year-old female presented to the hospital with a one-week history of pain and redness in her right axilla. Her relevant medical history included multiple skin abscesses secondary to "skin popping", heroin abuse for 18 years, and hepatitis C. The physical examination revealed "skin popping" lesions, bilateral costovertebral angle tenderness, and bilateral knee swelling. The laboratory workup was significant for renal insufficiency with a serum creatinine of 5 mg/dL and 14.8 grams of urine protein per 1 gram of urine creatinine. The renal biopsy findings were consistent with a diagnosis of renal amyloidosis due to serum amyloid A deposition and acute tubulointerstitial nephritis. Conclusions: AA renal amyloidosis among heroin addicts seems to be associated with chronic suppurative skin infection secondary to "skin popping". It is postulated that the chronic immunologic stimulation by one or more exogenous antigens or multiple acute inflammatory episodes is an important factor in the pathogenesis of amyloidosis in these patients. Therefore, AA renal amyloidosis should always be considered in chronic heroin users presenting with proteinuria and renal impairment