273 research outputs found
Deep learning-based algorithm for assessment of knee osteoarthritis severity in radiographs matches performance of radiologists
A fully-automated deep learning algorithm matched performance of radiologists
in assessment of knee osteoarthritis severity in radiographs using the
Kellgren-Lawrence grading system.
To develop an automated deep learning-based algorithm that jointly uses
Posterior-Anterior (PA) and Lateral (LAT) views of knee radiographs to assess
knee osteoarthritis severity according to the Kellgren-Lawrence grading system.
We used a dataset of 9739 exams from 2802 patients from Multicenter
Osteoarthritis Study (MOST). The dataset was divided into a training set of
2040 patients, a validation set of 259 patients and a test set of 503 patients.
A novel deep learning-based method was utilized for assessment of knee OA in
two steps: (1) localization of knee joints in the images, (2) classification
according to the KL grading system. Our method used both PA and LAT views as
the input to the model. The scores generated by the algorithm were compared to
the grades provided in the MOST dataset for the entire test set as well as
grades provided by 5 radiologists at our institution for a subset of the test
set.
The model obtained a multi-class accuracy of 71.90% on the entire test set
when compared to the ratings provided in the MOST dataset. The quadratic
weighted Kappa coefficient for this set was 0.9066. The average quadratic
weighted Kappa between all pairs of radiologists from our institution who took
a part of study was 0.748. The average quadratic-weighted Kappa between the
algorithm and the radiologists at our institution was 0.769.
The proposed model performed demonstrated equivalency of KL classification to
MSK radiologists, but clearly superior reproducibility. Our model also agreed
with radiologists at our institution to the same extent as the radiologists
with each other. The algorithm could be used to provide reproducible assessment
of knee osteoarthritis severity
Economic evaluation of access to musculoskeletal care: The case of waiting for total knee arthroplasty
BACKGROUND: The projected demand for total knee arthroplasty is staggering. At its root, the solution involves increasing supply or decreasing demand. Other developed nations have used rationing and wait times to distribute this service. However, economic impact and cost-effectiveness of waiting for TKA is unknown. METHODS: A Markov decision model was constructed for a cost-utility analysis of three treatment strategies for end-stage knee osteoarthritis: 1) TKA without delay, 2) a waiting period with no non-operative treatment and 3) a non-operative treatment bridge during that waiting period in a cohort of 60 year-old patients. Outcome probabilities and effectiveness were derived from the literature. Costs were estimated from the societal perspective with national average Medicare reimbursement. Effectiveness was expressed in quality-adjusted life years (QALYs) gained. Principal outcome measures were average incremental costs, effectiveness, and quality-adjusted life years; and net health benefits. RESULTS: In the base case, a 2-year wait-time both with and without a non-operative treatment bridge resulted in a lower number of average QALYs gained (11.57 (no bridge) and 11.95 (bridge) vs. 12.14 (no delay). The average cost was 1,810 less than wait-time with non-operative bridge. The incremental cost-effectiveness ratio comparing wait-time with no bridge to TKA without delay was $2,901/QALY. When comparing TKA without delay to waiting with non-operative bridge, TKA without delay produced greater utility at a lower cost to society. CONCLUSIONS: TKA without delay is the preferred cost-effective treatment strategy when compared to a waiting for TKA without non-operative bridge. TKA without delay is cost saving when a non-operative bridge is used during the waiting period. As it is unlikely that patients waiting for TKA would not receive non-operative treatment, TKA without delay may be an overall cost-saving health care delivery strategy. Policies aimed at increasing the supply of TKA should be considered as savings exist that could indirectly fund those strategies
Gated pipelined folding ADC based low power sensor for large-scale radiometric partial discharge monitoring
Partial discharge is a well-established metric for condition assessment of high-voltage plant equipment. Traditional techniques for partial discharge detection involve physical connection of sensors to the device under observation, limiting sensors to monitoring of individual apparatus, and therefore, limiting coverage. Wireless measurement provides an attractive low-cost alternative. The measurement of the radiometric signal propagated from a partial discharge source allows for multiple plant items to be observed by a single sensor, without any physical connection to the plant. Moreover, the implementation of a large-scale wireless sensor network for radiometric monitoring facilitates a simple approach to high voltage fault diagnostics. However, accurate measurement typically requires fast data conversion rates to ensure accurate measurement of faults. The use of high-speed conversion requires continuous high-power dissipation, degrading sensor efficiency and increasing cost and complexity. Thus, we propose a radiometric sensor which utilizes a gated, pipelined, sample-and-hold based folding analogue-todigital converter structure that only samples when a signal is received, reducing the power consumption and increasing the efficiency of the sensor. A proof of concept circuit has been developed using discrete components to evaluate the performance and power consumption of the system
Effects of Genetic Variants Previously Associated with Fasting Glucose and Insulin in the Diabetes Prevention Program
Common genetic variants have been recently associated with fasting glucose and insulin levels in white populations. Whether these associations replicate in pre-diabetes is not known. We extended these findings to the Diabetes Prevention Program, a clinical trial in which participants at high risk for diabetes were randomized to placebo, lifestyle modification or metformin for diabetes prevention. We genotyped previously reported polymorphisms (or their proxies) in/near G6PC2, MTNR1B, GCK, DGKB, GCKR, ADCY5, MADD, CRY2, ADRA2A, FADS1, PROX1, SLC2A2, GLIS3, C2CD4B, IGF1, and IRS1 in 3,548 Diabetes Prevention Program participants. We analyzed variants for association with baseline glycemic traits, incident diabetes and their interaction with response to metformin or lifestyle intervention. We replicated associations with fasting glucose at MTNR1B (P<0.001), G6PC2 (P = 0.002) and GCKR (P = 0.001). We noted impaired β-cell function in carriers of glucose-raising alleles at MTNR1B (P<0.001), and an increase in the insulinogenic index for the glucose-raising allele at G6PC2 (P<0.001). The association of MTNR1B with fasting glucose and impaired β-cell function persisted at 1 year despite adjustment for the baseline trait, indicating a sustained deleterious effect at this locus. We also replicated the association of MADD with fasting proinsulin levels (P<0.001). We detected no significant impact of these variants on diabetes incidence or interaction with preventive interventions. The association of several polymorphisms with quantitative glycemic traits is replicated in a cohort of high-risk persons. These variants do not have a detectable impact on diabetes incidence or response to metformin or lifestyle modification in the Diabetes Prevention Program
Estimating the bispectrum of the Very Small Array data
We estimate the bispectrum of the Very Small Array data from the compact and
extended configuration observations released in December 2002, and compare our
results to those obtained from Gaussian simulations. There is a slight excess
of large bispectrum values for two individual fields, but this does not appear
when the fields are combined. Given our expected level of residual point
sources, we do not expect these to be the source of the discrepancy. Using the
compact configuration data, we put an upper limit of 5400 on the value of f_NL,
the non-linear coupling parameter, at 95 per cent confidence. We test our
bispectrum estimator using non-Gaussian simulations with a known bispectrum,
and recover the input values.Comment: 17 pages, 16 figures, replaced with version accepted by MNRAS.
Primordial bispectrum recalculated and figure 11 change
Automated Grading of Radiographic Knee Osteoarthritis Severity Combined with Joint Space Narrowing
The assessment of knee osteoarthritis (KOA) severity on knee X-rays is a
central criteria for the use of total knee arthroplasty. However, this
assessment suffers from imprecise standards and a remarkably high inter-reader
variability. An algorithmic, automated assessment of KOA severity could improve
overall outcomes of knee replacement procedures by increasing the
appropriateness of its use. We propose a novel deep learning-based five-step
algorithm to automatically grade KOA from posterior-anterior (PA) views of
radiographs: (1) image preprocessing (2) localization of knees joints in the
image using the YOLO v3-Tiny model, (3) initial assessment of the severity of
osteoarthritis using a convolutional neural network-based classifier, (4)
segmentation of the joints and calculation of the joint space narrowing (JSN),
and (5), a combination of the JSN and the initial assessment to determine a
final Kellgren-Lawrence (KL) score. Furthermore, by displaying the segmentation
masks used to make the assessment, our algorithm demonstrates a higher degree
of transparency compared to typical "black box" deep learning classifiers. We
perform a comprehensive evaluation using two public datasets and one dataset
from our institution, and show that our algorithm reaches state-of-the art
performance. Moreover, we also collected ratings from multiple radiologists at
our institution and showed that our algorithm performs at the radiologist
level.
The software has been made publicly available at
https://github.com/MaciejMazurowski/osteoarthritis-classification
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Aging is associated with positive responding to neutral information but reduced recovery from negative information
Studies on aging and emotion suggest an increase in reported positive affect, a processing bias of positive over negative information, as well as increasingly adaptive regulation in response to negative events with advancing age. These findings imply that older individuals evaluate information differently, resulting in lowered reactivity to, and/or faster recovery from, negative information, while maintaining more positive responding to positive information. We examined this hypothesis in an ongoing study on Midlife in the US (MIDUS II) where emotional reactivity and recovery were assessed in a large number of respondents (N = 159) from a wide age range (36–84 years). We recorded eye-blink startle magnitudes and corrugator activity during and after the presentation of positive, neutral and negative pictures. The most robust age effect was found in response to neutral stimuli, where increasing age is associated with a decreased corrugator and eyeblink startle response to neutral stimuli. These data suggest that an age-related positivity effect does not essentially alter the response to emotion-laden information, but is reflected in a more positive interpretation of affectively ambiguous information. Furthermore, older women showed reduced corrugator recovery from negative pictures relative to the younger women and men, suggesting that an age-related prioritization of well-being is not necessarily reflected in adaptive regulation of negative affect
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Aging is associated with a prefrontal lateral-medial shift during picture-induced negative affect
The capacity to adaptively respond to negative emotion is in part dependent upon lateral areas of the prefrontal cortex (PFC). Lateral PFC areas are particularly susceptible to age-related atrophy, which affects executive function (EF). We used structural and functional magnetic resonance imaging (MRI) to test the hypothesis that older age is associated with greater medial PFC engagement during processing of negative information, and that this engagement is dependent upon the integrity of grey matter structure in lateral PFC as well as EF. Participants (n = 64, 38–79 years) viewed negative and neutral scenes while in the scanner, and completed cognitive tests as part of a larger study. Grey matter probability (GMP) was computed to index grey matter integrity. FMRI data demonstrated less activity in the left ventrolateral PFC (VLPFC) and greater ventromedial PFC (VMPFC) activity with increasing age during negative-picture viewing. Age did not correlate with amygdala responding. GMP in VLPFC and EF were negatively associated with VMPFC activity. We conclude that this change from lateral to medial PFC engagement in response to picture-induced negative affect reflects decreased reliance on executive function-related processes, possibly associated with reduced grey matter in lateral PFC, with advancing age to maintain emotional functioning
Molecular Characterization of Haemaphysalis Species and a Molecular Genetic Key for the Identification of Haemaphysalis of North America
Haemaphysalis longicornis (Acari: Ixodidae), the Asian longhorned tick, is native to East Asia, but has become established in Australia and New Zealand, and more recently in the United States. In North America, there are other native Haemaphysalis species that share similar morphological characteristics and can be difficult to identify if the specimen is damaged. The goal of this study was to develop a cost-effective and rapid molecular diagnostic assay to differentiate between exotic and native Haemaphysalis species to aid in ongoing surveillance of H. longicornis within the United States and help prevent misidentification. We demonstrated that restriction fragment length polymorphisms (RFLPs) targeting the 16S ribosomal RNA and the cytochrome c oxidase subunit I (COI) can be used to differentiate H. longicornis from the other Haemaphysalis species found in North America. Furthermore, we show that this RFLP assay can be applied to Haemaphysalis species endemic to other regions of the world for the rapid identification of damaged specimens. The work presented in this study can serve as the foundation for region specific PCR-RFLP keys for Haemaphysalis and other tick species and can be further applied to other morphometrically challenging taxa
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