scholarly journals Anal canal to pubis angle: a novel clinical ultrasound technique for the assessment of the anorectal region

2021 ◽  
Author(s):  
Victoria Asfour ◽  
Kayleigh Gibbs ◽  
David Wertheim ◽  
Giuseppe Alessandro Digesu ◽  
Ruwan Fernando ◽  
...  
Keyword(s):  
Anal Canal ◽  
Angle Measurement ◽  
Observer Agreement ◽  
Posterior Compartment ◽  
Midsagittal Plane ◽  
Ultrasound Technique ◽  
Angle Measurements ◽  
2D Ultrasound ◽  
Anorectal Region ◽  
Posterior Prolapse

Abstract Introduction and hypothesis Posterior compartment prolapse is associated with severe morbidity including faecal incontinence and defaecation dysfunction. The aim of this study was to develop and validate a novel ultrasound marker (anal canal to pubis angle) for the assessment of the anal axis in the context of posterior compartment prolapse in women and in controls (healthy, nulliparous, non-pregnant volunteers). Methods Anal canal to pubis (AC/Pubis) angle is measured with 2D transperineal ultrasound in precisely the midsagittal plane. The image was inverted and zoomed out and the angle opened to 107° (maximum). The image includes the pubis, urethra and anal canal. The angle measurement starts from the anal canal, pivots on the anorectal junction and ends at the shadow of the pubis. Inter- and intra-observer agreement in AC/Pubis angle measurement was assessed and the angles measured in the two groups compared. Results Forty women with posterior prolapse and 17 controls were included. Close agreement was observed in inter- and intra-observer AC/Pubis angle measurements assessed with Bland-Altman analysis. AC/Pubis angle is significantly wider in prolapse patients compared to controls (t-test, p < 0.001), with mean AC/Pubis angle in prolapse patients 122.9° (SD 15.6°) and controls 98.2° (SD 15.9°). Conclusion The AC/Pubis angle is a novel validated 2D ultrasound technique for the assessment of the anorectal axis that potentially can be performed using equipment that is widely available in routine clinical practice. The AC/Pubis angle is significantly wider in prolapse patients compared to controls.

Goniometric Versus Computerized Angle Measurement in Assessing Hallux Valgus

2005 ◽  
Vol 26 (3) ◽  
pp. 234-238 ◽  
Author(s):  
Daniel C. Farber ◽  
James K. DeOrio ◽  
Maxwell W. Steel
Keyword(s):  
Hallux Valgus ◽  
Plain Film ◽  
Angle Measurement ◽  
Observer Agreement ◽  
Computer Assisted ◽  
Intraobserver Agreement ◽  
Digital Radiographs ◽  
Plain Films ◽  
Correct Alignment ◽  
Standard Radiographs

Background: Digital workstations with high-resolution monitors are replacing standard radiographs for image evaluation and interpretation. Radiographic angles in the foot have been evaluated for interobserver and intraobserver reliability with plain films, but use of digital workstations has not been validated. Because the 1-2 intermetatarsal (IM) and hallux valgus (HV) angles help determine the most appropriate bunion procedure, the reliability of these measurements is important. Methods: The HV and 1-2 IM angles were evaluated on preoperative radiographs of 25 patients who subsequently underwent bunion procedures. A standardized technique using a film marker and goniometer on plain film was compared with use of a mouse and computerized angle measurement software at a digital workstation. Three foot and ankle surgeons conducted these measurements at various intervals. Completion of three readings of each radiograph in each format by each observer totaled 1,800 measurements. Results: Computerized measurement gave better overall reliability. For the HV angle, inter-observer agreement (measurements within 2 degrees) improved from 66% with plain films to 81% with the digital workstation (p < 0.001). Intraobserver agreement increased from 72% to 80%. The 1-2 IM angle was similarly reliable with both methods for inter- and intraobserver agreement. Conclusions: This study validates the use of computer-assisted angle measurement on digital radiographs for assessment of HV and 1-2 IM angles. Computerized measurement may result in more reliable readings because it eliminates the error inherent with use of a goniometer and facilitates adjustment of radiographic lines on the computer to ensure correct alignment.

scholarly journals Ultrasound imaging of the perineal body: a useful clinical tool

2019 ◽  
Vol 31 (6) ◽  
pp. 1197-1202
Author(s):  
Victoria Asfour ◽  
Giuseppe Alessandro Digesu ◽  
Ruwan Fernando ◽  
Vik Khullar
Keyword(s):  
Body Height ◽  
Ultrasound Measurement ◽  
Control Group ◽  
Anatomical Location ◽  
Body Measurements ◽  
Perineal Body ◽  
Clinical Tool ◽  
Posterior Compartment ◽  
Cross Sectional ◽  
2D Ultrasound

Abstract Introduction and hypothesis The perineal body is a fibromuscular pyramidal structure located between the vagina and the anus. It has been difficult to image because of its small size and anatomical location. This study used 2D transperineal ultrasound to measure the perineal body and assess whether there is an association with prolapse. Methods An observational, cross-sectional study was carried out in a tertiary level Urogynaecology department and included prolapse patients and healthy nulliparous volunteers (control group). This was a clinical assessment, including POP-Q and trans-perineal 2D ultrasound measurement of the perineal body height, length, perimeter, and area. Parametric tests were used, as the data were normally distributed. Results are reported as mean and 95% confidence interval (±95% CI). Results A total of 101 participants were recruited of which 22 were nulliparous healthy volunteers. Mean perineal body measurements in controls were height 22.5 ± 3.3 mm, length 17.4 ± 2.7 mm, perimeter 7.5 ± 0.9 mm, and area 2.8 ± 0.38 cm2. Perineal body measurements in 79 prolapse patients: height 16.9 ± 1.7 mm, length 16.0 ± 1.4 mm, perimeter 6.5 ± 0.5 mm and area 2.1 ± 0.5 cm2. A small perineal body was strongly associated with posterior compartment prolapse (paired t test, p < 0.0001) and wider POP-Q GH (paired t test, p = 0.0003). Surprisingly, Pelvic Organ Prolapse Quantification Perineal Body (POP-Q PB) of the two groups was not significantly different. A perineal body mid-sagittal area of less than 2.4 cm2 has been shown to be associated strongly with posterior compartment prolapse. Conclusions It is possible to measure the perineal body on 2D ultrasound. This technique facilitates the objective diagnosis of perineal deficiency. POP-Q PB does not predict the length or area of the perineal body.

Angle Measurements with Laser

2012 ◽  
Vol 239-240 ◽  
pp. 206-213
Author(s):  
Yang Wang ◽  
Chang Xiang Yan ◽  
Zhi Liang Gao
Keyword(s):  
Ring Laser ◽  
Angle Measurement ◽  
Internal Reflection ◽  
Laser Interference ◽  
Reflection Effect ◽  
Angle Measurements

Laser is widely used in angle measurements. This paper presents several frequently used methods of angle measurement that utilize laser, including：autocollimation angle measurement, angle measurement based on internal-reflection effect, laser interference angle measurement, angle measurement with ring laser and angle measurement with CCD. The principle, actualities, application situation, superiority and defects of each method are discussed.

A Comparative Study of Basic Edge Angle Measurement Techniques

1980 ◽  
Vol 45 (4) ◽  
pp. 857-865 ◽  
Author(s):  
Harold L. Dibble ◽  
Mary C. Bernard
Keyword(s):  
Comparative Study ◽  
Measurement Techniques ◽  
Angle Measurement ◽  
Relative Accuracy ◽  
Statistical Analyses ◽  
Edge Angle ◽  
Angle Measurements ◽  
Measuring Techniques

Four methods of edge angle measurements, including one developed by the authors, are applied to a sample of unretouched flakes in order to determine their relative accuracy, reliability, and economy. The authors discuss various statistical analyses which are available and essential in evaluating the significance of variability between and within the different measuring techniques, applying them to the results obtained from this study.

From plane to spatial angles: PTB’s spatial angle autocollimator calibrator

2015 ◽  
Vol 4 (5-6) ◽  
Author(s):  
Oliver Kranz ◽  
Ralf D. Geckeler ◽  
Andreas Just ◽  
Michael Krause ◽  
Wolfgang Osten
Keyword(s):  
Contact Angle ◽  
Mathematical Modelling ◽  
Angle Measurement ◽  
Specific Measurement ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Calibration Device ◽  
Set Up

AbstractElectronic autocollimators are utilised versatilely for non-contact angle measurements in applications like straightness measurements and profilometry. Yet, no calibration of the angle measurement of an autocollimator has been available when both its measurement axes are engaged. Additionally, autocollimators have been calibrated at fixed distances to the reflector, although its distance may vary during the use of an autocollimator. To extend the calibration capabilities of the Physikalisch-Technische Bundesanstalt (PTB) regarding spatial angles and variable distances, a novel calibration device has been set up: the spatial angle autocollimator calibrator (SAAC). In this paper, its concept and its mechanical realisation will be presented. The focus will be on the system’s mathematical modelling and its application in spatial angle calibrations. The model considers the misalignments of the SAAC’s components, including the non-orthogonalities of the measurement axes of the autocollimators and of the rotational axes of the tilting unit. It allows us to derive specific measurement procedures to determine the misalignments

scholarly journals Synchronous Generator Out of Step Detection Using Real Time Load Angle Data

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3336
Author(s):  
Ivan Višić ◽  
Ivan Strnad ◽  
Ante Marušić
Keyword(s):  
Power System ◽  
Real Time ◽  
Synchronous Generator ◽  
Angle Measurement ◽  
Impedance Change ◽  
Generator Protection ◽  
Angle Measurements ◽  
Angle Data ◽  
Key Issues ◽  
Load Angle

Although the power system usually always appears stable and reliable to consumers, a lot of work and research goes into keeping the power system both stable and reliable under constantly changing conditions and in these increasingly demanding times. One of the key issues in the power system is maintaining stability after large disturbances in order to prevent the loss of synchronicity of the generators in the system. Today’s generator protection systems mostly use measurements of impedance change to detect generator out of step. This article discusses the possibility of detecting the loss of synchronicity by using real time load angle measurements. The authors propose a real time load angle measurement algorithm and present the results of the algorithm’s testing performed on a real hydrogenerator. The results show that the developed algorithm gives highly accurate real time load angle measurements with the maximum possible resolution and that the load angle can be used for detecting the synchronous generator out of step.

Measurement and improvement of the adhesion of copper to polyimide

1999 ◽  
Vol 14 (10) ◽  
pp. 4025-4034 ◽  
Author(s):  
M. Menezes ◽  
I. M. Robertson ◽  
H. K. Birnbaum
Keyword(s):  
Contact Angle ◽  
Interfacial Adhesion ◽  
Reasonable Agreement ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Polyimide Substrate ◽  
Copper Clusters ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Strength Of Adhesion

A contact angle measurement technique has been used to obtain an estimate of the interfacial energy and thermodynamic adhesive strength between copper and polyimide [pyromellitic dyanhydride oxydianalyn (PMDA-ODA) and p-phenylene biphenyltetracarboinide (BPDA-PDA)]. Values of the strength of adhesion from these contact angle measurements are in reasonable agreement with values calculated using the Girifalco–Good–Fowkes nonpolar interfacial adhesion theory. Based on the surface energy it was predicted and experimentally observed that small copper clusters would embed into the polymer matrix if heated under ultrahigh vacuum conditions at temperatures near Tg of the polymer. Controlled embedding of nanometer clusters was utilized to produce a textured interface, where the partially embedded clusters acted as “nanonails” to anchor a metal overlayer to the underlying polyimide substrate. These nanonails greatly increased the bonding between the copper overlayer and the polyimide, as demonstrated by mechanical debonding studies.

Comparison of MRI, CT, Dunn 45° and Dunn 90° alpha angle measurements in femoroacetabular impingement

2017 ◽  
Vol 28 (4) ◽  
pp. 450-455 ◽  
Author(s):  
Kevin M. Smith ◽  
Brayden J. Gerrie ◽  
Patrick C. McCulloch ◽  
David M. Lintner ◽  
Joshua D. Harris
Keyword(s):  
Femoroacetabular Impingement ◽  
Imaging Techniques ◽  
Alpha Angle ◽  
Sample Size Calculation ◽  
Test Sample ◽  
Angle Measurement ◽  
Angle Measurements ◽  
Labral Tears ◽  
Significant Difference ◽  
Cam Morphology

Purpose: To determine if a significant difference existed among alpha angle measurements between 4 imaging techniques, axial oblique CT and MRI, Dunn 45° and Dunn 90° plain radiographs, in patients with symptomatic cam femoroacetabular impingement (FAI) and labral tear. Methods: A single-surgeon prospective radiographic analysis of consecutive non-arthritic and non-dysplastic -patients with symptomatic FAI and labral tears who underwent surgery was performed. Alpha angle was measured using standard techniques as described by Nötzli. Cam morphology was defined via alpha angle measurement of >50.5 degrees. Group comparisons were made using ANOVA and chi-squared test. Sample size calculation was performed prior to study enrollment. Results: 31 subjects (16 female; 33.5 ± 10.5 years mean age) were included. There was a significant difference in alpha angle measurements between all 4 imaging techniques (F [3,120] = 8.144; p<0.001), with the Dunn 45° view (66.3 ± 11.4°) significantly greater than all 3 other techniques (Dunn 90° [57.5 ± 10.7°; p = 0.015], MRI [53.3 ± 11.5°; p<0.001], and CT (54.9 ± 11.6°; p = 0.001). There was no significant difference in alpha angle between Dunn 90°, MRI, and CT. There was a significant difference in the observed number of hips with cam morphology between imaging techniques (χ2 9.4; p = 0.025). Conclusions: The Dunn 45° radiograph yielded a significantly higher alpha angle than Dunn 90°, axial oblique MRI, and CT imaging modalities. Use of the Dunn 90° or axial oblique MRI or CT as the threshold for cam osteoplasty may result in untreated symptomatic cam FAI. The authors recommend the Dunn 45° radiograph as the most sensitive evaluation of cam morphology.

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