P4381Improvement of the PISA method in the setting of mitral regurgitation of complex geometry

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
C Papolla ◽  
J Adda ◽  
G Habib ◽  
R Rieu
Keyword(s):  
Mitral Regurgitation ◽  
Measurement Accuracy ◽  
Complex Geometry ◽  
Electromagnetic Flowmeter ◽  
Reference Value ◽  
Proximal Isovelocity Surface Area ◽  
Multiple Jets ◽  
Circular Orifice ◽  
Double Activation

Abstract Background Doppler echocardiographic methods, such as proximal isovelocity surface area (PISA) are used to quantify mitral regurgitations. However, their accuracy and reproducibility are still discussed, especially in case of mitral regurgitations of complex geometry. Purpose The aim of this study was to test in-vitro the accuracy of the PISA method depending on the shape and number of regurgitant flows. Methods Several regurgitant volumes (RV) were produced through various regurgitation severities and shapes in a left heart double activation simulator. Circular mitral regurgitation (MR) was performed with a circular orifice in a rigid plate. Triangular and oblong MR were performed by suturing the extremity of a bioprosthesis leaflet to the annulus. Multiple jets regurgitation was performed by suturing centrally the two leaflets of an anatomically shaped mitral valve made of hydrogel. A transesophageal echocardiography probe was used to acquire the data. The RV was calculated with the classical PISA method (hemispheric assumption), or by considering the PISA as a hemicylinder or a double hemisphere. It was then compared to a reference value obtained from an electromagnetic flowmeter measurement (accuracy ± 2 ml/min). Results A central and circular orifice was correctly quantified, as expected, with the hemispheric assumption (bias 0.2±1.9 ml, p=0.46). For a triangular central jet, the hemispheric assumption best estimated the RV (−3.5±14.8 ml, p=0.10). An oblong MR was underestimated with the hemispheric assumption (−18.3±14.9 ml, p<0.01) whereas the hemicylindrical assumption was more accurate (−0.2±5.8 ml, p=0.85). In case of 2 regurgitant jets, considering only the largest jet led to an important underestimation (−10.9±5.6 ml, p<0.01), whereas adding the two RV was more accurate (−1.2±8.2 ml, p=0.50). Conclusions In case of a single central orifice, the hemispheric assumption correctly quantified the MR. In case of an oblong orifice, the hemicylindrical assumption provided a good quantification with simple measurements. In case of multiple jets of different sizes, it was more accurate to consider both jets for RV calculation. Acknowledgement/Funding Képhalios part of Affluent Medical

scholarly journals The IG- file use to Gauge the Apical Diameter in Endodontics: An In Vitro Study

2018 ◽  
Vol 12 (1) ◽  
pp. 638-646 ◽  
Author(s):  
Massimo Amato ◽  
Alfredo Iandolo ◽  
Giuseppe Pantaleo ◽  
Dina Abtellatif ◽  
Michele Simeone ◽  
...  
Keyword(s):  
Measurement Accuracy ◽  
Reference Value ◽  
In Vitro Study ◽  
Vitro Study ◽  
Root Canals ◽  
New Instrument ◽  
Clinician Experience ◽  
Incorrect Measurement ◽  
The Difference

Aim: The aim of this study was to evaluate the efficacy of the IG-file, a new instrument designed for apical diameter gauging. Materials and Methods: After shaping with F1 Universal Protaper, 60 roots were randomly divided into two groups and assigned to two operators, One Expert in Endodontics (EO) and One Unexpert (UO). In each sample, after canal curvatures have been detected, the apical diameters were measured with the IG-file and the K-NiTi. The results were compared with the reference value obtained by retrograde apical gauging. The data were statistically analyzed. Results: Among 60 samples, 10% of errors were recorded when the IG-files were used; in the K-NiTi group the incorrect measurements were 70%. In both groups (expert and unexpert) the IG-file measurements were more accurate than the K-NiTi (90 vs 33 and 90 vs 26,7). The differences were statistically significant. In curved canals, the difference between measurement rates performed with both instruments was statistically significant (85,7% IG-file vs 28,6% K-NiTi) as well as for the samples without curvatures (92,3% IG file vs 30,8% NiTi file). In root canals without curvatures overestimation errors in K-NiTi file group are more frequent than underestimation errors. This difference was statistically significant. Conclusion: A proper gauging of the apical diameter has a key role in endodontic therapy; an incorrect measurement can lead to clinical failures. This “in vitro” study highlights that IG-file improves measurement accuracy independently from clinician experience. Furthermore, in curved canals, the IG-file is more accurate than K-NiTi.

Abstract 16560: Impact of Assuming a Circular Orifice on Flow Error Through Elliptical Regurgitant Orifices: A Computational Fluid Dynamics (CFD) Analysis

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Sumeet S Mitter ◽  
Gregory J Wagner ◽  
Alex J Barker ◽  
Michael Markl ◽  
James D Thomas
Keyword(s):  
Mitral Valve ◽  
Hydrodynamic Theory ◽  
Axis Ratio ◽  
Orifice Area ◽  
Proximal Isovelocity Surface Area ◽  
Valve Orifice ◽  
Circular Orifice ◽  
Flow Through ◽  
Valve Orifice Area

Introduction: Hydrodynamic theory predicts fluid approaches a point orifice with accelerating velocity in hemispheric shells, forming the basis for the proximal isovelocity surface area (PISA) method to quantify valve regurgitation. Previous CFD and in vitro work has shown that with a finite, non-point orifice, there is a small, systematic underestimation of flow that is approximately the ratio of contour velocity (va) to maximal orifice velocity (vo), e.g., roughly an 8% error if a 40 cm/s contour is used with a 5 m/s jet. The PISA method is further questioned in the setting of noncircular orifices, with concerns of further underestimation. We sought to quantify this impact with CFD. Hypothesis: Application of standard PISA analysis to an elliptical orifice leads to further flow underestimation, but the magnitude is negligible. Methods: Mathematical modeling of flow through a finite elliptical orifice was computed using the open-source incompressible flow solver Nalu. Forty-five permutations of valve flow were characterized by varying valve orifice area (0.1, 0.3 and 0.5 cm^2), ellipse axis ratios (1:1, 2:1, 3:1, 5:1, and 10:1), and max velocity (400, 500 and 600 cm/s). Computed hemispherical flow contours scaled to true orifice flow (Qc/Qo) and scaled computed area to true orifice area (Ac/Ao) were plotted against distance from the orifice scaled to a circular orifice with equivalent orifice area. Results: Qc/Qo and Ac/Ao for each ellipse axis ratio when plotted against normalized orifice distance produced the same curves for each permutation of valve orifice area and max velocity. Plotting Qc/Qo (or Ac/Ao) against va/vo reveals marginal underestimation of flow with physiologic elliptical axis ratios of 2:1 and 3:1 against a circular orifice with axis ratios of 1:1 (Figure 1). Conclusions: The added error in using PISA to approximate flow through an elliptical mitral valve orifice area is minimal compared to traditional assumptions of a circular mitral valve orifice.

500 An in vitro steady flow model of mitral regurgitation by three-dimensional Doppler

1999 ◽  
Vol 1 ◽  
pp. S86-S86
Author(s):  
R DESIMONE ◽  
G GLOMBITZA ◽  
C VAHL ◽  
H MEINZER ◽  
S HAGL
Keyword(s):  
Mitral Regurgitation ◽  
Steady Flow ◽  
Flow Model ◽  
Three Dimensional

scholarly journals Rectus Femoris Mimicking Ultrasound Phantom for Muscle Mass Assessment: Design, Research, and Training Application

2021 ◽  
Vol 10 (12) ◽  
pp. 2721
Author(s):  
Nobuto Nakanishi ◽  
Shigeaki Inoue ◽  
Rie Tsutsumi ◽  
Yusuke Akimoto ◽  
Yuko Ono ◽  
...  
Keyword(s):  
Measurement Accuracy ◽  
Rectus Femoris ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Phantom Model ◽  
Ultrasound Measurements ◽  
Ultrasound Phantom

Ultrasound has become widely used as a means to measure the rectus femoris muscle in the acute and chronic phases of critical illness. Despite its noninvasiveness and accessibility, its accuracy highly depends on the skills of the technician. However, few ultrasound phantoms for the confirmation of its accuracy or to improve technical skills exist. In this study, the authors created a novel phantom model and used it for investigating the accuracy of measurements and for training. Study 1 investigated how various conditions affect ultrasound measurements such as thickness, cross-sectional area, and echogenicity. Study 2 investigated if the phantom can be used for the training of various health care providers in vitro and in vivo. Study 1 showed that thickness, cross-sectional area, and echogenicity were affected by probe compression strength, probe angle, phantom compression, and varying equipment. Study 2 in vitro showed that using the phantom for training improved the accuracy of the measurements taken within the phantom, and Study 2 in vivo showed the phantom training had a short-term effect on improving the measurement accuracy in a human volunteer. The new ultrasound phantom model revealed that various conditions affected ultrasound measurements, and phantom training improved the measurement accuracy.

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