Contour Map Point Distribution and Surgeon Experience Level Affect Accuracy of Surgical Navigation in a Pilot Study

2021 ◽  
pp. 000348942110059
Author(s):  
Jason Talmadge ◽  
Zi Yang Jiang ◽  
Denna A. Zebda ◽  
William C. Yao ◽  
Amber U. Luong ◽  
...  
Keyword(s):  
Surgical Navigation ◽  
Wide Field ◽  
Contour Map ◽  
Point Distribution ◽  
Field Mapping ◽  
Contour Maps ◽  
Experienced Surgeon ◽  
Surgeon Experience ◽  
Resident Surgeon ◽  
The Impact

Background: Reliable use of surgical navigation depends upon the registration process. The gold standard is paired-point registration with bone-anchored fiducials, but contour-map registration is more practical. Surgeons may employ variable contour maps and less experienced team members often perform this critical step. The impact of these practices on target registration error (TRE) is not well-studied. Methods: A dry lab set-up consisting of a navigation system (Fusion ENT, Medtronic, Jacksonville, FL) and a sinus phantom with 2 mm radiopaque spheres in the sphenoid and ethmoid regions was developed. A CT (0.625 mm slice thickness) was obtained. Registration was performed with a contour-based protocol. Accuracy was determined using the software’s distance measurement tool. Registration was performed with narrow-field (NF; forehead points medial to the mid-pupillary line) and wide field (WF; entire forehead) contour maps. An experienced rhinologist and a resident surgeon performed each registration in triplicate and TRE at the sphenoid and ethmoid markers was measured in triplicate. Results: WF mapping had a lower TRE than NF (1.09 mm [95% Confidence Interval (CI) 0.96-1.22] vs 1.68 mm [95% CI 1.50-1.86]). The experienced surgeon had a lower TRE compared to the resident (1.21 mm [95% CI 1.08-1.34] vs 1.54 mm [95% CI 1.35-1.74]). Conclusions: In this navigation model, wide field mapping offers better accuracy than narrow-field mapping, and an experienced surgeon seemed to achieve better accuracy than a resident surgeon. These observations have potential implications for the use of this technology in the operating room.

scholarly journals Blending and obscuration in weak lensing magnification

2021 ◽  
Author(s):  
E Gaztanaga ◽  
S J Schmidt ◽  
M D Schneider ◽  
J A Tyson
Keyword(s):  
Systematic Errors ◽  
Weak Lensing ◽  
Wide Field ◽  
Photometric Redshifts ◽  
Field Surveys ◽  
Systematic Effects ◽  
The Impact ◽  
Close Pairs ◽  
Mass Profiles

Abstract We test the impact of some systematic errors in weak lensing magnification measurements with the COSMOS 30-band photo-z Survey flux limited to Iauto < 25.0 using correlations of both source galaxy counts and magnitudes. Systematic obscuration effects are measured by comparing counts and magnification correlations. We use the ACS-HST catalogs to identify potential blending objects (close pairs) and perform the magnification analyses with and without blended objects. We find that blending effects start to be important (∼ 0.04 mag obscuration) at angular scales smaller than 0.1 arcmin. Extinction and other systematic obscuration effects can be as large as 0.10 mag (U-band) but are typically smaller than 0.02 mag depending on the band. After applying these corrections, we measure a 3.9σ magnification signal that is consistent for both counts and magnitudes. The corresponding projected mass profiles of galaxies at redshift z ≃ 0.6 (MI ≃ −21) is Σ = 25 ± 6M⊙h3/pc2 at 0.1 Mpc/h, consistent with NFW type profile with M200 ≃ 2 × 1012M⊙h/pc2. Tangential shear and flux-size magnification over the same lenses show similar mass profiles. We conclude that magnification from counts and fluxes using photometric redshifts has the potential to provide complementary weak lensing information in future wide field surveys once we carefully take into account systematic effects, such as obscuration and blending.

scholarly journals Intravitreal Anti-Vascular Endothelial Growth Factor Agents for the Treatment of Diabetic Retinopathy: A Review of the Literature

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1137
Author(s):  
Irini Chatziralli ◽  
Anat Loewenstein
Keyword(s):  
Diabetic Retinopathy ◽  
Vitreous Hemorrhage ◽  
Fundus Photography ◽  
Panretinal Photocoagulation ◽  
Wide Field ◽  
Vascular Endothelial ◽  
Keywords Diabetic Retinopathy ◽  
Anti Vegf ◽  
The Impact

Background: Diabetic retinopathy (DR) is the leading cause of blindness in the working-age population. The purpose of this review is to gather the existing literature regarding the use of the approved anti-vascular endothelial growth (anti-VEGF) agents in the treatment of DR. Methods: A comprehensive literature review in PubMed engine search was performed for articles written in English language up to 1 July 2021, using the keywords “diabetic retinopathy”, “ranibizumab”, “aflibercept”, and “anti-VEGF”. Emphasis was given on pivotal trials and recent robust studies. Results: Intravitreal anti-VEGF agents have been found to significantly improve visual acuity and reduce retinal thickness in patients with diabetic macular edema (DME) in a long-term follow-up ranging from 1 to 5 years and are considered the standard-of-care in such patients. Regarding DR, intravitreal anti-VEGF agents provided ≥2-step improvement in DR severity on color fundus photography in about 30–35% of patients with NPDR at baseline, in the majority of clinical trials originally designed to evaluate the efficacy of intravitreal anti-VEGF agents in patients with DME. Protocol S and CLARITY study have firstly reported that intravitreal anti-VEGF agents are non-inferior to panretinal photocoagulation (PRP) in patients with proliferative DR (PDR). However, the use of new imaging modalities, such as optical coherence tomography-angiography and wide-field fluorescein angiography, reveals conflicting results about the impact of anti-VEGF agents on the regression of retinal non-perfusion in patients with DR. Furthermore, one should consider the high “loss to follow-up” rate and its devastating consequences especially in patients with PDR, when deciding to treat the latter with intravitreal anti-VEGF agents alone compared to PRP. In patients with PDR, combination of treatment of intravitreal anti-VEGF agents and PRP has been also supported. Moreover, in the specific case of vitreous hemorrhage or tractional retinal detachment as complications of PDR, intravitreal anti-VEGF agents have been found to be beneficial as an adjunct to pars plana vitrectomy (PPV), most commonly given 3–7 days before PPV, offering reduction in the recurrence of vitreous hemorrhage. Conclusions: There is no general consensus regarding the use of intravitreal anti-VEGF agents in patients with DR. Although anti-VEGF agents are the gold standard in the treatment of DME and seem to improve DR severity, challenges in their use exist and should be taken into account in the decision of treatment, based on an individualized approach.

scholarly journals D2 Lymphadenectomy for Gastric Adenocarcinoma: Long-term Results and the Impact of Surgeon Experience on the Survival Rates

Chirurgia ◽  
2018 ◽  
Vol 113 (6) ◽  
pp. 772
Author(s):  
Stefan Tudor ◽  
Traian Dumitrascu ◽  
Mircea Manuc ◽  
Bogdan Trandafir ◽  
Mihnea Ionescu ◽  
...  
Keyword(s):  
Gastric Adenocarcinoma ◽  
Survival Rates ◽  
Long Term Results ◽  
D2 Lymphadenectomy ◽  
Surgeon Experience ◽  
The Impact

scholarly journals Surgeon Reliability for the Assessment of Lumbar Spinal Stenosis on MRI: The Impact of Surgeon Experience

10.14444/4034 ◽  
2017 ◽  
Vol 11 (5) ◽  
pp. 34 ◽  
Author(s):  
Satyajit V. Marawar ◽  
Ian A. Madom ◽  
Mark Palumbo ◽  
Richard A. Tallarico ◽  
Nathaniel R. Ordway ◽  
...  
Keyword(s):  
Spinal Stenosis ◽  
Lumbar Spinal Stenosis ◽  
Surgeon Experience ◽  
Lumbar Spinal ◽  
The Impact

VALMAP2.0: contour maps using the bond-valence-sum method

1999 ◽  
Vol 32 (2) ◽  
pp. 341-344 ◽  
Author(s):  
Javier González-Platas ◽  
Cristina González-Silgo ◽  
Catalina Ruiz-Pérez
Keyword(s):  
Arbitrary Point ◽  
Bond Valence ◽  
Steric Effects ◽  
Contour Map ◽  
Structural Investigations ◽  
Disorder Phase Transition ◽  
Contour Maps ◽  
Bond Valence Sum ◽  
Bond Valence Model ◽  
Microsoft Windows

VALMAP2.0 is a Microsoft-Windows-based program designed to assist material scientists in accurate structural investigations. The aim ofVALMAPis to calculate the sum of bond valences that a particular atom would have if it were placed at any arbitrary point in the crystal. By movement of this atom through all possible points, its valence-sum contour map can be displayed. Parameters of the bond-valence model are available and may be modified. The program was tested in a number of cases and two examples of applications are reported: (i) finding probable atom sites in crystal structures; (ii) displacive and order–disorder phase transition mechanisms, analysing steric effects.

Deriving Traffic-Performance Measures and Levels of Service from Second-Order Statistical Features of Spatiotemporal Traffic Contour Maps

2003 ◽  
Vol 1858 (1) ◽  
pp. 148-157 ◽  
Author(s):  
Sherif Ishak
Keyword(s):  
Intelligent Transportation Systems ◽  
Traffic Management ◽  
Performance Monitoring ◽  
Transportation Systems ◽  
Second Order ◽  
Level Of Service ◽  
Large Set ◽  
Contour Map ◽  
Contour Maps ◽  
Statistical Measures

Little information has been successfully extracted from the wealth of data collected by intelligent transportation systems. Such information is needed for the efficiency of operations and management functions of traffic-management centers. A new set of second-order statistical measures derived from texture characterization techniques in the field of digital image analysis is presented. The main objective is to improve the data-analysis tools used in performance-monitoring systems and assessment of level of service. The new measures can extract properties such as smoothness, homogeneity, regularity, and randomness in traffic operations directly from constructed spatiotemporal traffic contour maps. To avoid information redundancy, a correlation matrix was examined for nearly 14,000 15-min speed contour maps generated for a 3.4-mi freeway section over a period of 5 weekdays. The result was a set of three second-order measures: angular second moment, contrast, and entropy. Each measure was analyzed to examine its sensitivity to various traffic conditions, expressed by the overall speed mean of each contour map. The study also presented a tentative approach, similar to the conventional one used in the Highway Capacity Manual, to evaluate the level of service for each contour map. The new set of level-of-service criteria can be applied in real time by using a stand-alone module that was developed in the study. The module can be readily implemented online and allows traffic-management center operators to tune a large set of related parameters.

Innovative Method for Efficient Real Time Online Well Monitoring to Enhance Crew Respond Time in Marginal Field

2021 ◽  
Author(s):  
Dias Anugrah Massewa ◽  
Muhammad Rifaat ◽  
Ferdyan Ihza Akbar ◽  
Rahmanda Fadri ◽  
Denny Mulia Akbar ◽  
...  
Keyword(s):  
Real Time ◽  
Human Error ◽  
Smart Phone ◽  
Wide Field ◽  
C Language ◽  
Measurement Tools ◽  
Production Crew ◽  
Marginal Field ◽  
The Impact ◽  
Smart Phone Application

Abstract Previously, well monitoring in Siak block relied on production crew scheduled tour that needed six hours to complete one cycle of all wells in Lindai field. This paper describes the utilization of digital technology to observe well parameters while sending notification if there is any anomaly regarding those parameters through smart phone application or website. Smart microcontroller was installed in wellhead panel and three sensors are mounted in desired point around wellhead to perform online Intelligent Well Monitoring (IWM) for well’s parameters. If abnormality occurs, real time notification would be sent to user’s smart phone application or website by using global mobile communication system (GSM) signal. The parameters monitored were pressure, temperature, and load because they are essential to be analyzed as initial diagnosis of well problem. Based on the readings, production team could quickly perform troubleshooting to prevent loss production opportunity (LPO). The programming of this smart microcontroller used C language as data compiler. This method was tested in one of the wells in Lindai field, which has the highest oil production. After three months of surveillance, in terms of data quality, the values shown by this tool had only five percent differences compared to manual survey using calibrated measurement tools. Additionally, the parameters could be monitored online, real time, and gave the notification directly to users should there be any issues. Moreover, this tool could reduce the response time of the field crew significantly from six hours following the conventional field tour to only in five minutes by relying on real time notification. In addition, the operational cost of this tool was 82% cheaper compared to other well-known online monitoring tool available in the market so it is considered economical. In the long term, this tool will be implemented on all wells in Siak block for integrated real time monitoring. Furthermore, the impact of field scale implementation will be much greater such as increasing data accuracy by eliminating human error from manual well checking and improving safety of the crew by reducing the possibility of fatigue. The utilization of smart microcontroller for online well monitoring is beneficial for marginal field with high number of wells and wide field coverage. Earlier, real time well monitoring is usually considered expensive investment that rarely become priority. However, the implementation of IoT (Internet of Things) by using this tool can be the game changer in marginal field and maximize the well’s production by reducing LPO.

scholarly journals Optical characterization of WISE selected blazar candidates

2019 ◽  
Vol 630 ◽  
pp. A55 ◽  
Author(s):  
Raniere de Menezes ◽  
Harold A. Peña-Herazo ◽  
Ezequiel J. Marchesini ◽  
Raffaele D’Abrusco ◽  
Nicola Masetti ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Optical Spectra ◽  
Sloan Digital Sky Survey ◽  
Wide Field ◽  
Large Area ◽  
Bl Lac Objects ◽  
True Nature ◽  
Normal Galaxies ◽  
Data Release ◽  
The Impact

Context. Over the last decade more than five thousand γ-ray sources have been detected by the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope. Given the positional uncertainty of the telescope, nearly 30% of these sources remain without an obvious counterpart at lower energies. This has motivated the release of new catalogs of γ-ray counterpart candidates and several follow up campaigns in the last decade. Aims. Recently, two new catalogs of blazar candidates were released. These are the improved and expanded version of the WISE Blazar-Like Radio-Loud Sources (WIBRaLS2) catalog and the Kernel Density Estimation selected candidate BL Lacs (KDEBLLACS) catalog, both selecting blazar-like sources based on their infrared colors from the Wide-field Infrared Survey Explorer (WISE). In this work we characterize these two catalogs, clarifying the true nature of their sources based on their optical spectra from SDSS data release 15, thus testing their efficiency in selecting true blazars. Methods. We first selected all WIBRaLS2 and KDEBLLACS sources with available optical spectra in the footprint of Sloan Digital Sky Survey data release 15. We then analyzed these spectra to verify the nature of each selected candidate and to measure the fraction of the catalogs composed by spectroscopically confirmed blazars. Finally, we evaluated the impact of selection effects, especially those related to optical colors of WIBRaLS2/KDEBLLACS sources and their optical magnitude distributions. Results. We found that at least ∼30% of each catalog is made up of confirmed blazars, with quasars being the major contaminants in the case of WIBRaLS2 (≈58%) and normal galaxies in the case of KDEBLLACS (≈38.2%). The spectral analysis also allowed us to identify the nature of 11 blazar candidates of uncertain type (BCUs) from the Fermi-LAT fourth Point Source Catalog (4FGL) and to find 25 new BL Lac objects.

Developing Decision Boundaries for Left-Turn Treatments

2020 ◽  
Vol 2674 (5) ◽  
pp. 315-326
Author(s):  
Michael Adamson ◽  
Grant G. Schultz ◽  
Mitsuru Saito ◽  
Michael D. Stevens
Keyword(s):  
Linear Regression Analysis ◽  
Simulation Models ◽  
Assessment Model ◽  
Final Decision ◽  
Contour Map ◽  
Left Turn ◽  
Contour Maps ◽  
Traffic Volumes ◽  
Decision Boundaries ◽  
Statistical Analysis Software

The purpose of this research was to evaluate the interaction of left-turn and opposing through traffic volumes for permitted and protected left-turn phasing at intersections and develop boundaries that help identify when to switch from permitted to protected phasing at signalized intersections. Permitted phasing allows vehicles to turn left after yielding to opposing vehicles; protected phasing provides an exclusive phase for vehicles to turn left without opposition; and protected-permitted phasing combines these phasing alternatives, allowing both permitted and protected turning movements. Intersections with 1, 2, and 3 opposing-lane configurations with permitted and protected-permitted models (split into green times of 10, 15, and 20 s) were analyzed for a total of 12 simulation models. Each model was divided into 100–225 different volume scenarios, with incremental increases in left-turn and opposing volumes. By exporting trajectory files from VISSIM and importing these into the Surrogate Safety Assessment Model, crossing conflicts for each volume combination in each model were extracted. MATLAB was then used to create contour maps representing the number of crossing conflicts per hour associated with different combinations of left-turn and opposing volume. Basic decision boundaries were examined in each contour map. Statistical analysis software was used to perform a linear regression analysis on transformed data and to develop natural log-based equations that form the decision boundaries for each configuration and phase alternative. These equations were graphed and final decision boundaries developed for the 1-, 2-, and 3-lane configurations between permitted and protected-permitted phasing as well as between protected-permitted and protected phasing.

Sign in / Sign up

Export Citation Format

Share Document