Convolutional neural network-based single-shot speckle tracking for x-ray phase-contrast imaging.

X-ray phase-contrast imaging offers enhanced sensitivity for weakly-attenuating materials, such as breast and brain tissue, but has yet to be widely implemented clinically due to high coherence requirements and expensive x-ray optics. Speckle-based phase contrast imaging has been proposed as an affordable and simple alternative; however, obtaining high-quality phase-contrast images requires accurate tracking of sample-induced speckle pattern modulations. This study introduced a convolutional neural network to accurately retrieve sub-pixel displacement fields from pairs of reference (i.e., without sample) and sample images for speckle tracking. Speckle patterns were generated utilizing an in-house wave-optical simulation tool. These images were then randomly deformed and attenuated to generate training and testing datasets. The performance of the model was evaluated and compared against conventional speckle tracking algorithms: zero-normalized cross-correlation and unified modulated pattern analysis. We demonstrate improved accuracy (1.7 times better than conventional speckle tracking), bias (2.6 times), and spatial resolution (2.3 times), as well as noise robustness, window size independence, and computational efficiency. In addition, the model was validated with a simulated geometric phantom. Thus, in this study, we propose a novel convolutional-neural-network-based speckle-tracking method with enhanced performance and robustness that offers improved alternative tracking while further expanding the potential applications of speckle-based phase contrast imaging.

Loss of function of OTUD7A in the schizophrenia- associated 15q13.3 deletion impairs synapse development and function in human neurons.

Identifying causative gene(s) within disease-associated large genomic regions of copy-number variants (CNVs) is challenging. Here, by targeted sequencing of genes within schizophrenia (SZ)-associated CNVs in 1,779 SZ cases and 1,418 controls, we identified three rare putative loss-of-function (LoF) mutations in OTU deubiquitinase 7A (OTUD7A) within the 15q13.3 deletion in cases but none in controls. To tie OTUD7A LoF with any SZ-relevant cellular phenotypes, we modeled the OTUD7A LoF mutation, rs757148409, in human induced pluripotent stem cell (hiPSC)-derived induced excitatory neurons (iNs) by CRISPR-Cas9 engineering. The mutant iNs showed a ∼50% decrease in OTUD7A expression without undergoing nonsense-mediated mRNA decay. The mutant iNs also exhibited marked reduction of dendritic complexity, density of synaptic proteins GluA1 and PSD-95, and neuronal network activity. Congruent with the neuronal phenotypes in mutant iNs, our transcriptomic analysis showed that the set of OTUD7A LoF-downregulated genes was enriched for those relating to synapse development and function and was associated with SZ and other neuropsychiatric disorders. These results suggest that OTUD7A LoF impairs synapse development and neuronal function in human neurons, providing mechanistic insight into the possible role of OTUD7A in driving neuropsychiatric phenotypes associated with the 15q13.3 deletion.

Quantitative analysis of speckle-based X-ray dark-field imaging using numerical wave-optics simulations.

The dark-field signal measures the small-angle scattering strength and provides complementary diagnostic information. This is of particular interest for lung imaging due to the pronounced small-angle scatter from the alveolar microstructure. However, most dark-field imaging techniques are relatively complex, dose-inefficient, and require sophisticated optics and highly coherent X-ray sources. Speckle-based imaging promises to overcome these limitations due to its simple and versatile setup, only requiring the addition of a random phase modulator to conventional X-ray equipment. We investigated quantitatively the influence of sample structure, setup geometry, and source energy on the dark-field signal in speckle-based X-ray imaging with wave-optics simulations for ensembles of micro-spheres. We show that the dark-field signal is accurately predicted via a model originally derived for grating interferometry when using the mean frequency of the speckle pattern power spectral density as the characteristic speckle size. The size directly reflects the correlation length of the diffuser surface and did not change with energy or propagation distance within the near-field. The dark-field signal had a distinct dependence on sample structure and setup geometry but was also affected by beam hardening-induced modifications of the visibility spectrum. This study quantitatively demonstrates the behavior of the dark-field signal in speckle-based X-ray imaging.

Minimally Invasive Image-Guided Gut Transport Function Measurement Probe.

Introduction: Diseases such as celiac disease, environmental enteric dysfunction, infectious gastroenteritis, type II diabetes and inflammatory bowel disease are associated with increased gut permeability. Dual sugar absorption tests, such as the lactulose to rhamnose ratio (L:R) test, are the current standard for measuring gut permeability. Although easy to administer in adults, the L:R test has a number of drawbacks. These include an inability to assess for spatial heterogeneity in gut permeability that may distinguish different disease severity or pathology, additional sample collection for immunoassays, and challenges in carrying out the test in certain populations such as infants and small children. Here, we demonstrate a minimally invasive probe for real-time localized gut permeability evaluation through gut potential difference (GPD) measurement. Materials and Methods: The probe has an outer diameter of 1.2 mm diameter and can be deployed in the gut of unsedated subjects via a transnasal introduction tube (TNIT) that is akin to an intestinal feeding tube. The GPD probe consists of an Ag/AgCl electrode, an optical probe and a perfusion channel all housed within a transparent sheath. Lactated Ringer's (LR) solution is pumped through the perfusion channel to provide ionic contact between the electrodes and the gut lining. The optical probe captures non-scanning (M-mode) OCT images to confirm electrode contact with the gut lining. A separate skin patch probe is placed over an abraded skin area to provide reference for the GPD measurements. Swine studies were conducted to validate the GPD probe. GPD in the duodenum was modulated by perfusing 45 ml of 45 mM glucose. Results: GPD values of -13.1 ± 2.8 mV were measured in the duodenum across four swine studies. The change in GPD in the duodenum with the addition of glucose was -10.5 ± 2.4 mV (p < 0.001). M-mode OCT images provided electrode-tissue contact information, which was vital in ascertaining the probe's proximity to the gut mucosa. Conclusion: We developed and demonstrated a minimally invasive method for investigating gastrointestinal permeability consisting of an image guided GPD probe that can be used in unsedated subjects.

Anesthesia management of patients undergoing hyperthermic isolated limb perfusion with melphalan for melanoma treatment: an analysis of 17 cases.

BACKGROUND: Hyperthermic isolated limb perfusion (HILP) is used for patients with intractable or extensive in-transit metastatic melanoma of the limb to deliver high concentrations of cytotoxic agents to the affected limb and offers a treatment option in a disease stage with a poor prognosis when no treatment is given. METHODS: In a retrospective chart review of 17 cases, we studied the anesthetic and hemodynamic changes during HILP and its management. RESULTS: HILP was well tolerated except in one case that is described herein. We present summary data of all cases undergoing upper and lower limb perfusion, discuss our current clinical practice of preoperative, perioperative and intraoperative patient care including the management of HILP circuit. CONCLUSION: HILP is a challenging procedure, and requires a team effort including the surgical team, anesthesia care providers, perfusionists and nurses. Intraoperatively, invasive hemodynamic and metabolic monitoring is indispensable to manage significant hemodynamic and metabolic changes due to fluid shifts and release of cytokines.

Effectiveness of interventions for the assessment and prevention of falls in adult psychiatric patients: A systematic review.

BACKGROUND: Patient fall is among the top five sentinel events in hospitals due to the resultant functional loss and injury sustained. Precise fall risk assessment and prevention strategies are important components of a fall prevention program. Due to psychiatric conditions and medications, these patients may require a different fall management program compared to other patient populations. OBJECTIVE: The objective of this review was to identify the best available evidence for the effectiveness of nursing fall risk assessment tools, interventions to reduce incidence of falls, and common risk factors of adult psychiatric patients who fall. INCLUSION CRITERIA: Adults (19 to 64 years) diagnosed with mental illnessEvaluation of nursing fall risk assessment tools in adult psychiatric settings, and interventions, which minimised fall risk or fall rates.Number of patient falls during hospitalisation was the main outcome.Primary quantitative studies published in English language. SEARCH STRATEGY: The literature search sought published studies, and was limited to English language reports. There were no date restrictions applied to the search. Electronic databases searched included:CINAHLPubMedCochrane Central Register of Controlled TrialsPsycINFOScienceDirectScopusWeb of ScienceWiley-InterScienceProQuestMedNar METHODOLOGICAL QUALITY: Studies retrieved were assessed by two independent reviewers for methodological validity prior to inclusion in the review using standardised critical appraisal instruments from the Joanna Briggs Institute System for the Unified Management, Assessment and Review of Information (JBI-SUMARI). DATA EXTRACTION: Data including specific details about the methods, settings, purposes, populations, interventions, and outcomes significant to the review's objectives were extracted by two independent reviewers using standardised data extraction tools from JBI-SUMARI. RESULTS: Eleven studies were included in this review: three before-and-after studies, four descriptive studies, two case control studies and two cohort studies. Evidence with regards to the effectiveness of fall risk assessment tools and prevention strategies was inconclusive. Certain risk factors which were more frequently associated with falls included diagnoses of depression, bipolar disorder, and dementia / Alzheimer's disease, altered mental status, physiological symptoms, past history of falls, mobility and gait problems, concurrent medical conditions, polypharmacy, and taking of certain medications such as sedatives, antidepressants and mood stabilisers, particularly lithium. CONCLUSION: Evidence on the effectiveness of fall risk assessment tools and prevention strategies in psychiatric setting was inconclusive due to a paucity of studies. However, certain risk factors were found to be more commonly associated with falls in adult psychiatric patients (Level III Evidence).Constant observation of the side effects of medications, particularly orthostatic hypotension, and review of patients' medical profile by doctors or pharmacists may be helpful in preventing falls in psychiatric patients. Findings on common risk factors can better aid healthcare professionals in identifying psychiatric patients who are at risk for falls.More research is needed on the evaluation of fall risk assessment tools and fall prevention strategies, specifically for the adult psychiatric patients. More prospective and better quality studies examining fall risk factors in psychiatric patients are needed.

Transdermal scopolamine for the prevention of postoperative nausea and vomiting: a systematic review and meta-analysis.

BACKGROUND: Transdermal scopolamine (TDS) is a potential long-acting prophylactic antiemetic initially developed to prevent motion sickness. TDS is a centrally acting anticholinergic agent that was approved in 2001 by the US Food and Drug Administration for the prevention of postoperative nausea and vomiting (PONV). Although TDS has been reported to be clinically efficacious in the prevention of PONV, several adverse events (AEs), such as sedation, dry mouth, blurred vision, central cholinergic syndrome, and confusion (particularly in elderly patients with mild cognitive impairment), are potential concerns. OBJECTIVE: The aim of this study was to explore the efficacy and tolerability of TDS in the prevention of PONV in adults. METHODS: A systematic search of PubMed, EMBASE, and the Cochrane Library for randomized controlled trials in adults that compared the effects of TDS and placebo on postoperative nausea, vomiting, and PONV was conducted in March 2009, and an update was conducted in July 2010. Without any language restrictions, a search with the following terms was performed: postoperative, postoperative, postanesthe*, postanaesthe*, post-anesthe*, post-anaesthe*, anesthesia, anaesthesia, surgery, surgeries, surgical, nausea, vomiting, emesis, retching, scopolamine, and hyoscine. Identified studies were then hand-searched for further relevant literature. RESULTS: Data from 25 randomized controlled trials were analyzed (N = 3298). In the postanesthesia care unit, TDS was associated with a significantly reduced risk for postoperative nausea compared with placebo (relative risk [RR] = 0.77; 95% CI, 0.61-0.98; P = 0.03). TDS was also associated with a significantly reduced risk for postoperative nausea (RR = 0.59; 95% CI, 0.48-0.73; P < 0.001), postoperative vomiting (RR = 0.68; 95% CI, 0.61-0.76; P < 0.001), and PONV (RR = 0.73; 95% CI, 0.60-0.88; P = 0.001) during the first 24 hours after the start of anesthesia. TDS appeared to be effective compared with placebo in the prevention of postoperative nausea when treatment was initiated the night before (early application) (RR = 0.56; 95% CI, 0.41-0.75; P < 0.001) or on the day of surgery (late application) (RR = 0.61; 95% CI, 0.47-0.79; P < 0.001). TDS was associated with a higher prevalence of visual disturbances at 24 to 48 hours compared with placebo (RR = 3.35; 95% CI, 1.78-6.32). Analyses of confusion and other AEs did not show a significant association with TDS. CONCLUSIONS: In this systematic review and metaanalysis, TDS was associated with significant reductions in PONV with both early and late patch application during the first 24 hours after the start of anesthesia. TDS was associated with a higher prevalence of visual disturbances at 24 to 48 hours after surgery, but no other AEs, compared with placebo.