Nevin Manimala

J Nucl Cardiol. 2021 Mar 2. doi: 10.1007/s12350-021-02555-4. Online ahead of print.

ABSTRACT

BACKGROUND: A variety of temporal sampling protocols is used worldwide to measure myocardial blood flow (MBF). Both the length and number of time frames in these protocols may alter MBF and myocardial flow reserve (MFR) measurements. We aimed to assess the effect of different clinically used temporal sampling protocols on MBF and MFR quantification in Rubidium-82 (Rb-82) PET imaging.

METHODS: We retrospectively included 20 patients referred for myocardial perfusion imaging using Rb-82 PET. A literature search was performed to identify appropriate sampling protocols. PET data were reconstructed using 14 selected temporal sampling protocols with time frames of 5-10 seconds in the first-pass phase and 30-120 seconds in the tissue phase. Rest and stress MBF and MFR were calculated for all protocols and compared to the reference protocol with 26 time frames.

RESULTS: MBF measurements differed (P ≤ 0.003) in six (43%) protocols in comparison to the reference protocol, with mean absolute relative differences up to 16% (range 5%-31%). Statistically significant differences were most frequently found for protocols with tissue phase time frames < 90 seconds. MFR did not differ (P ≥ 0.11) for any of the protocols.

CONCLUSIONS: Various temporal sampling protocols result in different MBF values using Rb-82 PET. MFR measurements were more robust to different temporal sampling protocols.

PMID:33655444 | DOI:10.1007/s12350-021-02555-4

Surg Endosc. 2021 Mar 2. doi: 10.1007/s00464-021-08353-w. Online ahead of print.

ABSTRACT

BACKGROUND: Achalasia is a rare, chronic, and morbid condition with evolving treatment. Peroral endoscopic myotomy (POEM) has gained considerable popularity, but its comparative effectiveness is uncertain. We aim to evaluate the literature comparing POEM to Heller myotomy (HM) and pneumatic dilation (PD) for the treatment of achalasia.

METHODS: We conducted a systematic review of comparative studies between POEM and HM or PD. A priori outcomes pertained to efficacy, perioperative metrics, and safety. Internal validity of observational studies and randomized trials (RCTs) was judged using the Newcastle Ottawa Scale and the Cochrane Risk of Bias 2.0 tool, respectively.

RESULTS: From 1379 unique literature citations, we included 28 studies comparing POEM and HM (n = 21) or PD (n = 8), with only 1 RCT addressing each. Aside from two 4-year observational studies, POEM follow-up averaged ≤ 2 years. While POEM had similar efficacy to HM, POEM treated dysphagia better than PD both in an RCT (treatment “success” RR 1.71, 95% CI 1.34-2.17; 126 patients) and in observational studies (Eckardt score MD – 0.43, 95% CI – 0.71 to – 0.16; 5 studies; I² 21%; 405 patients). POEM needed reintervention less than PD in an RCT (RR 0.19, 95% CI 0.08-0.47; 126 patients) and HM in an observational study (RR 0.33, 95% CI 0.16, 0.68; 98 patients). Though 6-12 months patient-reported reflux was worse than PD in 3 observational studies (RR 2.67, 95% CI 1.02-7.00; I² 0%; 164 patients), post-intervention reflux was inconsistently measured and not statistically different in measures ≥ 1 year. POEM had similar safety outcomes to both HM and PD, including treatment-related serious adverse events.

CONCLUSIONS: POEM has similar outcomes to HM and greater efficacy than PD. Reflux remains a critical outcome with unknown long-term clinical significance due to insufficient data and inconsistent reporting.

PMID:33655443 | DOI:10.1007/s00464-021-08353-w

Chin Med J (Engl). 2021 Feb 9;134(5):564-572. doi: 10.1097/CM9.0000000000001400.

ABSTRACT

BACKGROUND: The pathogenesis of osteosarcoma (OS) is still unclear, and it is still necessary to find new targets and drugs for anti-OS. This study aimed to investigate the role and mechanism of the anti-OS effects of miR-296-5p.

METHODS: We measured the expression of miR-296-5p in human OS cell lines and tissues. The effect of miR-296-5p and its target gene staphylococcal nuclease and tudor domain containing 1 on proliferation, migration, and invasion of human OS lines was examined. The Student’s t test was used for statistical analysis.

RESULTS: We found that microRNA (miR)-296-5p was significantly downregulated in OS cell lines and tissues (control vs. OS, 1.802 ± 0.313 vs. 0.618 ± 0.235, t = 6.402, P < 0.01). Overexpression of miR-296-5p suppressed proliferation, migration, and invasion of OA cells. SND1 was identified as a target of miR-296-5p by bioinformatic analysis and dual-luciferase reporter assay. Overexpression of SND1 abrogated the effects induced by miR-296-5p upregulation (miRNA-296-5p vs. miRNA-296-5p + SND1, 0.294 ± 0.159 vs. 2.300 ± 0.277, t = 12.68, P = 0.003).

CONCLUSION: Our study indicates that miR-296-5p may function as a tumor suppressor by targeting SND1 in OS.

PMID:33652459 | DOI:10.1097/CM9.0000000000001400

Phys Med Biol. 2021 Mar 2. doi: 10.1088/1361-6560/abeb32. Online ahead of print.

ABSTRACT

Virtual imaging trials (VITs), defined as the process of conducting clinical imaging trials using computer simulations, offer a time- and cost-effective alternative to traditional imaging trials for CT. The clinical potential of VITs hinges on the realism of simulations modeling the image acquisition process, where the accurate scanner-specific simulation of scatter in a time- feasible manner poses a particular challenge. To meet this need, this study proposes, develops, and validates a rapid scatter estimation framework, based on GPU-accelerated Monte Carlo (MC) simulations and denoising methods, for estimating scatter in single source, dual-source, and photon-counting CT. A CT simulator was developed to incorporate parametric models for an anti-scatter grid and a curved energy integrating detector (EID) with an energy-dependent response. The scatter estimates from the simulator were validated using physical measurements acquired on a clinical CT system using the standard single-blocker method. The MC simulator was further extended to incorporate a pre-validated model for a photon-counting detector and an additional source-detector pair to model cross scatter in dual-source configurations. To estimate scatter with desirable levels of statistical noise using a manageable computational load, two denoising methods using a (1) convolutional neural network and an (2) optimized Gaussian filter were further deployed. The viability of this framework for clinical VITs was assessed by integrating it with a scanner-specific ray-tracer program to simulate images for an image quality (Mercury) and an anthropomorphic phantom (XCAT). The simulated scatter-to-primary ratios agreed with physical measurements within 4.4%10.8% across all projection angles and kVs. The differences of ~121 HU between images with and without scatter, signifying the importance of scatter for simulating clinical images. The denoising methods preserved the magnitudes and trends observed in the reference scatter distributions, with an averaged rRMSE value of 0.91 and 0.97 for the two methods, respectively. The execution time of ~30 seconds for simulating scatter in a single projection with a desirable level of statistical noise indicates a major improvement in performance, making our tool an eligible candidate for conducting extensive VITs spanning multiple patients and scan protocols.

PMID:33652421 | DOI:10.1088/1361-6560/abeb32

Neural Netw. 2021 Feb 17;138:140-149. doi: 10.1016/j.neunet.2021.02.007. Online ahead of print.

ABSTRACT

Few-shot learning aims to classify unseen classes with a few training examples. While recent works have shown that standard mini-batch training with carefully designed training strategies can improve generalization ability for unseen classes, well-known problems in deep networks such as memorizing training statistics have been less explored for few-shot learning. To tackle this issue, we propose self-augmentation that consolidates self-mix and self-distillation. Specifically, we propose a regional dropout technique called self-mix, in which a patch of an image is substituted into other values in the same image. With this dropout effect, we show that the generalization ability of deep networks can be improved as it prevents us from learning specific structures of a dataset. Then, we employ a backbone network that has auxiliary branches with its own classifier to enforce knowledge sharing. This sharing of knowledge forces each branch to learn diverse optimal points during training. Additionally, we present a local representation learner to further exploit a few training examples of unseen classes by generating fake queries and novel weights. Experimental results show that the proposed method outperforms the state-of-the-art methods for prevalent few-shot benchmarks and improves the generalization ability.

PMID:33652370 | DOI:10.1016/j.neunet.2021.02.007

J Crit Care. 2021 Feb 20;63:98-103. doi: 10.1016/j.jcrc.2021.02.004. Online ahead of print.

ABSTRACT

PURPOSE: Vascular access patterns in the intensive care unit (ICU) have shifted from non-tunneled central venous catheters (CVCs) towards peripherally inserted central catheters (PICCs). We evaluated perceptions of critical care practitioners regarding these devices and variation in evidence-based practice.

MATERIALS: A 35-question survey on ICU vascular access was deployed in 13 Michigan hospitals. Descriptive statistics summarized responses. Differences in utilization, perceptions and evidence-based practices between PICCs and CVCs, by participant and site-level characteristics, were assessed.

RESULTS: 314 of 621 eligible providers responded to the survey (response rate 51%). 15% of providers reported not routinely using ultrasound when placing CVCs. Respondents whom were trainees, from larger hospitals, and from closed ICUs were more likely to use ultrasound (p < 0.001). Additionally, 21% of respondents stated they did not specify number of CVC lumens, while 46% did not specify number of PICC lumens (p < 0.001). The likelihood of specifying PICC lumens increased when vascular access protocols were in place (p = 0.001). 2/3 of respondents (n = 173, 66%) stated more research on ICU vascular access was needed.

CONCLUSION: Variation in guideline-based vascular access practices exists in the ICU. Defined local protocols may improve guideline adherence. Studies evaluating vascular access decisions and patient safety in the ICU appear necessary.

PMID:33652363 | DOI:10.1016/j.jcrc.2021.02.004

Sex Reprod Healthc. 2021 Feb 24;28:100608. doi: 10.1016/j.srhc.2021.100608. Online ahead of print.

ABSTRACT

OBJECTIVE: To examine the socio-demographic variations in overwhelming existence of C-section deliveries in south India, with a comparison to rest of India.

METHODS: This study analyses data collected from 51,136 mothers under National Family Health Survey (NFHS)-3 (2005-06) and 2,52,183 mothers under NFHS-4 (2015-16), those who have given births during last five years preceding the survey.

MAIN OUTCOME MEASURES: Descriptive statistics, bivariate analysis with Chi-squared tests and binary logistic regression models with 95% confidence intervals are used.

RESULTS: In south India at least one out of four women deliver through C-section and there was a notable rise in caesarean deliveries in public facilities as well as among tribal population. In aggregate, number of states exceeding 15% prevalence rate of C-section deliveries doubled to sixteen, while nineteen states registered more than 100% rise. Rural-urban difference is slim in south India, while likelihood for C-section deliveries for richest women as compared to poorest has gone down from 2.76 to 1.88 in south India and 7.75 to 4.58 in other regions during 2005-06 to 2015-16. The odds ratio for C-section is higher in private hospitals (3.26) of southern states with reference to public institutions, while the odds are 3.90 times higher for private facilities in other states. In south India, percentage of C-section deliveries were actually lower among those who reported about pregnancy complications.

CONCLUSIONS: Despite, several maternal and child health related programs being launched in India, their impact on improving the C-section scenario has remained microscopic, or they have continued to contribute towards a rising prevalence of C-section, especially in south India.

PMID:33652351 | DOI:10.1016/j.srhc.2021.100608

J Stroke Cerebrovasc Dis. 2021 Feb 27;30(5):105680. doi: 10.1016/j.jstrokecerebrovasdis.2021.105680. Online ahead of print.

ABSTRACT

INTRODUCTION: Body lateropulsion (BLP) is seen in neurological lesions involving the pathways responsible for body position and verticality. We report a case of isolated body lateropulsion (iBLP) as the presentation of lateral medullary infarction and conducted a systematic literature review.

METHODS: MEDLINE and EMBASE databases were searched up to December 3, 2020.

INCLUSION CRITERIA: age ≥ 18, presence of BLP, confirmed stroke on imaging.

EXCLUSION CRITERIA: age < 18, qualitative reviews, studies with inadequate patient data. Statistical analysis was performed using IBM® SPSS® Statistics 20.

RESULTS: A 64-year-old man presented with acute-onset iBLP. Brain MRI demonstrated acute infarction in the right caudolateral medulla. His symptoms progressed with ipsilateral Horner syndrome over the next 24 hours and contralateral hemisensory loss 10 days later. Repeat MRI showed an increase in infarct size. BLP resolved partially at discharge. Systematic review: 418 abstracts were screened; 59 studies were selected reporting 103 patients. Thirty-three patients had iBLP (32%). BLP was ipsilateral to stroke in 70 (68%) and contralateral in 32 (32%). The most common stroke locations were medulla (n = 63, 59%), pons (n = 16, 15%), and cerebellum (n = 16, 15%). Four strokes were cortical, 3 frontal and 1 temporoparietal (3%). The most common etiology was large-artery atherosclerosis (LAA) in 20 patients (32%), followed by small-vessel occlusion in 12 (19%). Seventeen (27%) had large-vessel occlusion (LVO), 12 involving the vertebral artery. Sixty (98%) had some degree of resolution of BLP; complete in 41 (70%). Median time-to-resolution was 14 days (IQR 10-21). There was no relationship between time-to-resolution and age, sex, side of BLP or side of stroke.

CONCLUSION: BLP was commonly seen with medullary infarction and was the isolated finding in one-third. LAA and LVO were the most common etiologies. Recovery of BLP was early and complete in most cases.

PMID:33652344 | DOI:10.1016/j.jstrokecerebrovasdis.2021.105680

Sci Total Environ. 2021 Feb 18;776:145935. doi: 10.1016/j.scitotenv.2021.145935. Online ahead of print.

ABSTRACT

Data-driven landslide susceptibility models formally integrate spatial landslide information with explanatory environmental variables that describe predisposing factors of slope instability. Well-performing models are commonly utilized to identify landslide-prone terrain or to understand the causes of slope instability. In most cases, however, the available landslide data is affected by spatial biases (e.g. underrepresentation of landslides far from infrastructure or in forests) and does therefore not perfectly represent the spatial distribution of past slope instabilities. Literature shows that implications of such data flaws are frequently ignored. This study was built upon landslide information that systematically relates to damage-causing and infrastructure-threatening events in South Tyrol, Italy (7400 km²). The created models represent three conceptually different strategies to deal with biased landslide information. The aims were to demonstrate why an inference of geomorphic causation from apparently well-performing models is invalid under common landslide data bias conditions (Model 1), to test a novel bias-adjustment approach (Model 2) and to exploit the underlying data bias to model areas likely affected by potentially damaging landslides (Model 3; intervention index), instead of landslide susceptibility. The study offers a novel perspective on how biases in landslide data can be considered within data-driven models by focusing not only on the process under investigation (landsliding), but also on the circumstances that led to the registration of landslide information (data collection effects). The results were evaluated in terms of statistical relationships, variable importance, predictive performance, and geomorphic plausibility. The results revealed that none of the models reflected landslide susceptibility. Despite partly high predictive performances, the models were unable to create geomorphically plausible spatial predictions. The impact-oriented intervention index, however, enabled to identify damage-causing landslides with high accuracy. We conclude that the frequent practice of inferring geomorphic causation from well-performing models without accounting for data limitations is invalid.

PMID:33652311 | DOI:10.1016/j.scitotenv.2021.145935

Sci Total Environ. 2021 Feb 18;776:145926. doi: 10.1016/j.scitotenv.2021.145926. Online ahead of print.

ABSTRACT

The estimation of geochemical background is complex in areas impacted by point sources of atmospheric emissions due to unknowns about pollutant dispersion, persistence of pollutants on the landscape, and natural concentrations of elements associated with parent material. This study combined mineralogical analysis with conventional statistical and geospatial methods to separate anthropogenically impacted soils from unimpacted soils in the Yellowknife area, Northwest Territories, Canada, a region that was exposed to 60 years of arsenic (As)-rich atmospheric mining emissions (1938-1999) and that hosts natural enrichments of As. High concentrations of As (up to 4700 mg kg^-1) were measured in publicly accessible soils near decommissioned roaster stacks in the region and strong relationships between As and distance from the main emission sources persisted in surface soils and soils at depth in the soil profile more than 60 years after the bulk of mining emissions were released. Mineralogical analysis provided unambiguous evidence regarding the source of As minerals and highlighted that most As in surface soils within 15 km of Yellowknife is hosted as anthropogenic arsenic trioxide (As₂O₃), produced by roaster stack emissions. Statistical protocols for the estimation of geochemical background were applied to an existing database of till geochemistry (N = 1490) after removing samples from mining impacted areas. Results suggested geochemical background for the region is 0.25-15 mg kg^-1 As, comparable to global averages, with upper thresholds elevated in volcanic units (30 mg kg^-1 As) that often host sulfide mineralization in greenstone belts in the region.

PMID:33652309 | DOI:10.1016/j.scitotenv.2021.145926