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Naoki Shikazono - One of the best experts on this subject based on the ideXlab platform.
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the effect of bubble acceleration on the liquid film thickness in micro tubes
International Journal of Heat and Fluid Flow, 2010Co-Authors: Naoki ShikazonoAbstract:Abstract Liquid film thickness is an important parameter for predicting boiling heat transfer in micro tubes. In the previous study ( Han and Shikazono, 2009a ), liquid film thickness under the steady condition was investigated and an empirical correlation for the initial liquid film thickness based on Capillary Number, Reynolds Number and Weber Number was proposed. However, under flow boiling conditions, bubble velocity is not constant but accelerated due to evaporation. It is necessary to consider this bubble acceleration effect on the liquid film thickness, since it affects viscous, surface tension and inertia forces in the momentum equation. In addition, viscous boundary layer develops, and it may also affect the liquid film thickness. In the present study, the effect of bubble acceleration is investigated. Laser focus displacement meter is used to measure the liquid film thickness. Ethanol, water and FC-40 are used as working fluids. Circular tubes with three different inner diameters, D = 0.5, 0.7 and 1.0 mm, are used. The increase of liquid film thickness with Capillary Number is restricted by the bubble acceleration. Finally, an empirical correlation is proposed for the liquid film thickness of accelerated flows in terms of Capillary Number and Bond Number based on the bubble acceleration.
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measurement of liquid film thickness in micro square channel
International Journal of Multiphase Flow, 2009Co-Authors: Naoki ShikazonoAbstract:Abstract In micro channels, slug flow becomes one of the main flow regimes due to strong surface tension. In micro channel slug flow, elongated bubble flows with the thin liquid film confined between the bubble and the channel wall. Liquid film thickness is an important parameter in many applications, e.g., micro heat exchanger, micro reactor, coating process etc. In the present study, liquid film thickness in micro square channels is measured locally and instantaneously with the confocal method. Square channels with hydraulic diameter of D h = 0.3, 0.5 and 1.0 mm are used. In order to investigate the effect of inertial force on the liquid film thickness, three working fluids, ethanol, water and FC-40 are used. At small Capillary Numbers, liquid film at the channel center becomes very thin and the bubble interface is not axisymmetric. However, as Capillary Number increases, bubble interface becomes axisymmetric. Transition from non-axisymmetric to axisymmetric flow pattern starts from lower Capillary Number as Reynolds Number increases. An empirical correlation for predicting axisymmetric bubble radius based on Capillary Number and Weber Number is proposed from the present experimental data.
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measurement of the liquid film thickness in micro tube slug flow
International Journal of Heat and Fluid Flow, 2009Co-Authors: Naoki ShikazonoAbstract:Slug flow is one of the representative flow regimes of two-phase flow in micro tubes. It is well known that the thin liquid film formed between the tube wall and the vapor bubble plays an important role in micro tube heat transfer. In the present study, experiments are carried out to clarify the effects of parameters that affect the formation of the thin liquid film in micro tube two-phase flow. Laser focus displacement meter is used to measure the thickness of the thin liquid film. Air, ethanol, water and FC-40 are used as working fluids. Circular tubes with five different diameters, D = 0.3, 0.5, 0.7, 1.0 and 1.3 mm, are used. It is confirmed that the liquid film thickness is determined only by Capillary Number and the effect of inertia force is negligible at small Capillary Numbers. However, the effect of inertia force cannot be neglected as Capillary Number increases. At relatively high Capillary Numbers, liquid film thickness takes a minimum value against Reynolds Number. The effects of bubble length, liquid slug length and gravity on the liquid film thickness are also investigated. Experimental correlation for the initial liquid film thickness based on Capillary Number, Reynolds Number and Weber Number is proposed.
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measurement of the liquid film thickness in micro tube slug flow
International Journal of Heat and Fluid Flow, 2009Co-Authors: Youngbae Han, Naoki ShikazonoAbstract:Slug flow is one of the representative flow regimes of two-phase flow in micro tubes. It is well known that the thin liquid film formed between the tube wall and the vapor bubble plays an important role in micro tube heat transfer. In the present study, experiments are carried out to clarify the effects of parameters that affect the formation of the thin liquid film in micro tube two-phase flow. Laser focus displacement meter is used to measure the thickness of the thin liquid film. Air, ethanol, water and FC-40 are used as working fluids. Circular tubes with five different diameters, D = 0.3, 0.5, 0.7, 1.0 and 1.3 mm, are used. It is confirmed that the liquid film thickness is determined only by Capillary Number and the effect of inertia force is negligible at small Capillary Numbers. However, the effect of inertia force cannot be neglected as Capillary Number increases. At relatively high Capillary Numbers, liquid film thickness takes a minimum value against Reynolds Number. The effects of bubble length, liquid slug length and gravity on the liquid film thickness are also investigated. Experimental correlation for the initial liquid film thickness based on Capillary Number, Reynolds Number and Weber Number is proposed.
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Theoretical and experimental study on liquid film thicknesses of unsteady slug flows in a Capillary tube
International Journal of Multiphase Flow, 2024Co-Authors: Young Jik Youn, Naoki Shikazono, Chan Kyu Lee, Hyun Wook KangAbstract:Abstract Liquid film thickness is an important parameter for predicting evaporation and condensation heat transfer performance of two-phase slug flow in a Capillary tube. Under flow boiling condition, the bubble of two-phase slug flow is elongated and accelerated. In the present study, the effect of acceleration on the liquid film thickness of unsteady two-phase slug flow is theoretically and experimentally investigated. It is first theoretically found that the accelerated slug flow is affected by the dimensionless Numbers of Capillary Number (Ca), Weber Number (We), and Bond Number (Bo). The relation of the dimensionless liquid film thickness with the Capillary Number, Weber Number, and Bond Number for unsteady accelerated slug flows was obtained. The liquid film thicknesses of two-phase slug flows under acceleration condition were directly measured using laser focus displacement metering technique. Circular Capillary tube with inner diameter of 1 mm was used for the test tube, and water, ethanol and FC-40 were used as working fluids. The novel prediction correlation of liquid film thickness for accelerated slug flows was proposed and it well predicts all the experimental data for all conditions. As the Bond Number increases, the liquid film thicknesses are gradually shifted in the direction of decreasing film thickness due to acceleration effect. At a fixed Capillary Number, initial liquid film thickness becomes thinner with increasing Bond Number.
Vanessa Smith - One of the best experts on this subject based on the ideXlab platform.
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ab1133 automated assessment autocapi of nailfold Capillary Number versus manual counting in systemic sclerosispatients with different capillaroscopic patterns
Annals of the Rheumatic Diseases, 2019Co-Authors: Maurizio Cutolo, Carmen Pizzorni, Vanessa Smith, Amber Vanhaecke, M Pendolino, Massimo Patane, V Tomatis, A SulliAbstract:Background The nailfold videocapillaroscopy (NVC) analysis allows microvascular detection of possible markers of severity and progression in systemic sclerosis (SSc), as reduced Capillary Number, which has been associated with a high risk of developing disease complications (i.e. digital ulcers over time) (1-2). A recent study validated an automated counting system (AUTOCAPI) for the absolute nailfold Capillary Number in SSc patients by analysing the capillaroscopic images (3). Objectives To evaluate the performance of this automated software for absolute nailfold Capillary Number counting, in SSc patients with different NVC patterns of microangiopathy. Methods 183 random SSc patients collected at both Genova and Ghent Divisions of Rheumatology were enrolled (LeRoy 2001 or ACR 2013 criteria, mean age 55±13 year, mean disease duration 5.5±6.8 years) and classified by NVC in the following patterns: 28 ”not specific”, 37 “early”, 89 “active”, 29 “late”). 8 fingers for each patient were analysed, counting the Number of nailfold capillaries manually and by the AUTOCAPI software (DS Medica, Italy) along a millimetre in each finger image. The mean Capillary Number value of the eight finger images was calculated. The software reliability was assessed through calculation of the intraclass correlation coefficient (ICC) between automatic and manual counting. Results The mean Number of capillaries assessed by manual vs automatic counting was as follows: 5.23±1.7 vs 5.47±1.3 in the total group of SSc patients, 5.91±1.2 vs 6.87±1.2 in the ”not specific”, 7.23±1.4 vs 5.67±1.1 in the “early”, 4.67±1.1 vs 5.16±1.2 in the “active” and 3.72±1.5 vs 4.85±1.1 in the “late” pattern of microangiopathy. The higher standard deviation observed for automatic counting was 1.23 in the ”not specific” group. The following ICC’s were obtained respectively for total patients, ”not specific”, “early”, “active”, and “late” NVC patterns: 0.53, 0.51, 0.48, 0.50 and 0.66. The mean values for the manual versus automatic Capillary counting assessed by the two centres in all SSc patients were respectively: 5.92±1.8 and 5.02±1.1 for Genova centre, and 4.71±1.5 and 5.83±1.4 for Ghent centre. The automatic counting confirmed that Capillary Number progressively reduces from ”early” to ”active” to ”late” NVC pattern of microangiopathy in SSc. Conclusion This study reports for the first time the good reliability of AUTOCAPI software in nailfold Capillary Number counting in SSc patients with different patterns of microangiopathy. The use of automated counting software need to standardize nailfold Capillary assessment among different Rheumatological centres. References [1] Smith V, et al. J Rheumatol. 2013;40:2023-8. 2. Cutolo M, et al. Arthritis Rheumatol. 2016;68:2527-39. 3. Cutolo M, et al. Microcirculation. 2018;25:e12447. Disclosure of Interests None declared
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automated assessment of absolute nailfold Capillary Number on videocapillaroscopic images proof of principle and validation in systemic sclerosis
Microcirculation, 2018Co-Authors: Maurizio Cutolo, A C Trombetta, Karin Melsens, Carmen Pizzorni, A Sulli, Barbara Ruaro, S Paolino, Ellen Deschepper, Vanessa SmithAbstract:Background: Absolute nailfold Capillary Number should be a putative biomarker in selected rheumatic diseases but could be time-consuming and not highly repeatable. Objective: To validate an automated software for absolute nailfold Capillary Number and density evaluation, on NVC images in SSc. Methods: An automated software to count nailfold Capillary Number (AUTOCAPI) had been constructed, through an exploratory image set. Subsequently, application rules have been created to define the ROI in NVC images, through a training images set. The software reliability was assessed through calculation of the ICC between automatic and manual counting, by four independent observers, on the same NVC images. Results: The following ICC's were obtained per observer, for the patients with SSc (40 images), the healthy (20 images), and the PRP subgroups (20 images), respectively: 0.94, 0.81, and 0.62 (observer 1); 0.94, 0.91, and 0.67 (observer 2); 0.88, 0.56, and 0.64 (observer 3); and 0.88, 0.85, and 0.85 (observer 4). Conclusions: The validation of an automated software for measuring absolute nailfold Capillary Number and density in SSc was achieved. The integration into the pre-existing imaging software should make the assessment of the Capillary Number in NVC easier, quicker, and standardized.
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sat0377 reliability of a new automated system for absolute Capillary Number counting autocapi on systemic sclerosis nailfold videocapillaroscopic images
Annals of the Rheumatic Diseases, 2017Co-Authors: Maurizio Cutolo, A C Trombetta, Karin Melsens, Carmen Pizzorni, A Sulli, Ellen Deschepper, Vanessa SmithAbstract:Background Nailfold Capillary density is a useful measure in systemic sclerosis (SSc) classification and evaluation. Its manual detection may be time-consuming, hampering its use in largescale investigations. We evaluated a new automated system to assess the absolute nailfold Capillary Number. Objectives To attest the instrumental reliability of automatic counting in SSc patients using nailfold video capillaroscopy (NVC) images. Methods 75 NVC random images, from SSc patients, were blindly analyzed by four raters (2 less and 2 more experienced; raters: 1,2,3,4) from two European centers. Each rater was asked to define the region of interest (ROI) on the NVC images and to manually count the Number of capillaries, according to the following instructions: upper bound placed on top of the longest Capillary head and lower bound placed on half of the length of that longest Capillary (figure 1); if the common branch of an abnormal shape (neoangiogenesis) is in ROI it is counted as being one; if the common branch is out of ROI it is counted as separate capillaries; if the Capillary is on the edge of the vertical line of ROI, it is only counted when the head of the Capillary is half in ROI; if the Capillary head is on the edge of lower bound, it is counted as soon as the “head” part is in the ROI; all “heads” in the ROI are counted (not only distal row). The dedicated automated system (AUTOCAPI-ds medica, IT) also counted the Number of capillaries in the same ROI (figure 1). Reliability between the manual and automatic counting was investigated per rater through intraclass correlation coefficient (ICC) and reported with 95% confidence interval (CI). External validation was obtained by multi-rating of the same set of images. Average difference between automated and manual counting per rater was calculated. Results The ICC (95% CI) of manual versus automatic counting in ROI was 0.77 (0.61–0.86) for rater 1 (p Conclusions This is a first study to attest the reliability of a new automated system to calculate the absolute Number of capillaries in a ROI arising from SSc NVC images. High performance of the new automated counting system was confirmed in pathological conditions (SSc). Disclosure of Interest None declared
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effects of longterm treatment with bosentan and iloprost on nailfold absolute Capillary Number fingertip blood perfusion and clinical status in systemic sclerosis
The Journal of Rheumatology, 2016Co-Authors: A C Trombetta, Carmen Pizzorni, A Sulli, S Paolino, Vanessa Smith, B Ruaro, Maurizio CutoloAbstract:Objective. To quantify in patients with systemic sclerosis (SSc) the absolute nailfold Capillary Number/mm (the absolute Number of capillaries, observable in the first row, in 1 mm per field) and fingertip blood perfusion (FBP) during longterm therapy with the endothelin receptor antagonist bosentan (BOSE) and the synthetic analog of prostacyclin PGI2 iloprost (ILO) by multiple diagnostic tools. Observed values were correlated with clinical outcomes. Methods. Thirty patients with SSc already receiving intravenous ILO (80 μg/day) for 5 continuous days (every 3 mos) were recruited in the clinic. Fifteen patients continued such treatment (ILO group), while in 15 patients BOSE (125 mg twice/day) was added (ILO + BOSE group) because of the onset of pulmonary arterial hypertension or digital ulcers (DU). The followup period was 4 years (T0–T4). Every year the following were evaluated: absolute nailfold Capillary Number/mm by nailfold videocapillaroscopy, FBP by laser Doppler flowmetry, DU incidence, DLCO, systolic pulmonary arterial pressure (sPAP), renal arterial resistive index, and other biomarkers. From T2 to T4, laser speckled contrast analysis was added. Nonparametric tests were used for statistical analysis. Results. Limited to the ILO + BOSE group, absolute Capillary Number/mm and FBP showed a progressive increase independently from other variables. In addition, during followup there was a significant reduction (80%) in the incidence of new DU, whereas DLCO and sPAP did not worsen. Conclusion. The study shows in patients with SSc with up to 4 years of combined therapy a progressive significant recovery in structure and function of microvasculature linked to improved clinical outcomes, independent of disease severity.
Maurizio Cutolo - One of the best experts on this subject based on the ideXlab platform.
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ab1133 automated assessment autocapi of nailfold Capillary Number versus manual counting in systemic sclerosispatients with different capillaroscopic patterns
Annals of the Rheumatic Diseases, 2019Co-Authors: Maurizio Cutolo, Carmen Pizzorni, Vanessa Smith, Amber Vanhaecke, M Pendolino, Massimo Patane, V Tomatis, A SulliAbstract:Background The nailfold videocapillaroscopy (NVC) analysis allows microvascular detection of possible markers of severity and progression in systemic sclerosis (SSc), as reduced Capillary Number, which has been associated with a high risk of developing disease complications (i.e. digital ulcers over time) (1-2). A recent study validated an automated counting system (AUTOCAPI) for the absolute nailfold Capillary Number in SSc patients by analysing the capillaroscopic images (3). Objectives To evaluate the performance of this automated software for absolute nailfold Capillary Number counting, in SSc patients with different NVC patterns of microangiopathy. Methods 183 random SSc patients collected at both Genova and Ghent Divisions of Rheumatology were enrolled (LeRoy 2001 or ACR 2013 criteria, mean age 55±13 year, mean disease duration 5.5±6.8 years) and classified by NVC in the following patterns: 28 ”not specific”, 37 “early”, 89 “active”, 29 “late”). 8 fingers for each patient were analysed, counting the Number of nailfold capillaries manually and by the AUTOCAPI software (DS Medica, Italy) along a millimetre in each finger image. The mean Capillary Number value of the eight finger images was calculated. The software reliability was assessed through calculation of the intraclass correlation coefficient (ICC) between automatic and manual counting. Results The mean Number of capillaries assessed by manual vs automatic counting was as follows: 5.23±1.7 vs 5.47±1.3 in the total group of SSc patients, 5.91±1.2 vs 6.87±1.2 in the ”not specific”, 7.23±1.4 vs 5.67±1.1 in the “early”, 4.67±1.1 vs 5.16±1.2 in the “active” and 3.72±1.5 vs 4.85±1.1 in the “late” pattern of microangiopathy. The higher standard deviation observed for automatic counting was 1.23 in the ”not specific” group. The following ICC’s were obtained respectively for total patients, ”not specific”, “early”, “active”, and “late” NVC patterns: 0.53, 0.51, 0.48, 0.50 and 0.66. The mean values for the manual versus automatic Capillary counting assessed by the two centres in all SSc patients were respectively: 5.92±1.8 and 5.02±1.1 for Genova centre, and 4.71±1.5 and 5.83±1.4 for Ghent centre. The automatic counting confirmed that Capillary Number progressively reduces from ”early” to ”active” to ”late” NVC pattern of microangiopathy in SSc. Conclusion This study reports for the first time the good reliability of AUTOCAPI software in nailfold Capillary Number counting in SSc patients with different patterns of microangiopathy. The use of automated counting software need to standardize nailfold Capillary assessment among different Rheumatological centres. References [1] Smith V, et al. J Rheumatol. 2013;40:2023-8. 2. Cutolo M, et al. Arthritis Rheumatol. 2016;68:2527-39. 3. Cutolo M, et al. Microcirculation. 2018;25:e12447. Disclosure of Interests None declared
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automated assessment of absolute nailfold Capillary Number on videocapillaroscopic images proof of principle and validation in systemic sclerosis
Microcirculation, 2018Co-Authors: Maurizio Cutolo, A C Trombetta, Karin Melsens, Carmen Pizzorni, A Sulli, Barbara Ruaro, S Paolino, Ellen Deschepper, Vanessa SmithAbstract:Background: Absolute nailfold Capillary Number should be a putative biomarker in selected rheumatic diseases but could be time-consuming and not highly repeatable. Objective: To validate an automated software for absolute nailfold Capillary Number and density evaluation, on NVC images in SSc. Methods: An automated software to count nailfold Capillary Number (AUTOCAPI) had been constructed, through an exploratory image set. Subsequently, application rules have been created to define the ROI in NVC images, through a training images set. The software reliability was assessed through calculation of the ICC between automatic and manual counting, by four independent observers, on the same NVC images. Results: The following ICC's were obtained per observer, for the patients with SSc (40 images), the healthy (20 images), and the PRP subgroups (20 images), respectively: 0.94, 0.81, and 0.62 (observer 1); 0.94, 0.91, and 0.67 (observer 2); 0.88, 0.56, and 0.64 (observer 3); and 0.88, 0.85, and 0.85 (observer 4). Conclusions: The validation of an automated software for measuring absolute nailfold Capillary Number and density in SSc was achieved. The integration into the pre-existing imaging software should make the assessment of the Capillary Number in NVC easier, quicker, and standardized.
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sat0377 reliability of a new automated system for absolute Capillary Number counting autocapi on systemic sclerosis nailfold videocapillaroscopic images
Annals of the Rheumatic Diseases, 2017Co-Authors: Maurizio Cutolo, A C Trombetta, Karin Melsens, Carmen Pizzorni, A Sulli, Ellen Deschepper, Vanessa SmithAbstract:Background Nailfold Capillary density is a useful measure in systemic sclerosis (SSc) classification and evaluation. Its manual detection may be time-consuming, hampering its use in largescale investigations. We evaluated a new automated system to assess the absolute nailfold Capillary Number. Objectives To attest the instrumental reliability of automatic counting in SSc patients using nailfold video capillaroscopy (NVC) images. Methods 75 NVC random images, from SSc patients, were blindly analyzed by four raters (2 less and 2 more experienced; raters: 1,2,3,4) from two European centers. Each rater was asked to define the region of interest (ROI) on the NVC images and to manually count the Number of capillaries, according to the following instructions: upper bound placed on top of the longest Capillary head and lower bound placed on half of the length of that longest Capillary (figure 1); if the common branch of an abnormal shape (neoangiogenesis) is in ROI it is counted as being one; if the common branch is out of ROI it is counted as separate capillaries; if the Capillary is on the edge of the vertical line of ROI, it is only counted when the head of the Capillary is half in ROI; if the Capillary head is on the edge of lower bound, it is counted as soon as the “head” part is in the ROI; all “heads” in the ROI are counted (not only distal row). The dedicated automated system (AUTOCAPI-ds medica, IT) also counted the Number of capillaries in the same ROI (figure 1). Reliability between the manual and automatic counting was investigated per rater through intraclass correlation coefficient (ICC) and reported with 95% confidence interval (CI). External validation was obtained by multi-rating of the same set of images. Average difference between automated and manual counting per rater was calculated. Results The ICC (95% CI) of manual versus automatic counting in ROI was 0.77 (0.61–0.86) for rater 1 (p Conclusions This is a first study to attest the reliability of a new automated system to calculate the absolute Number of capillaries in a ROI arising from SSc NVC images. High performance of the new automated counting system was confirmed in pathological conditions (SSc). Disclosure of Interest None declared
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effects of longterm treatment with bosentan and iloprost on nailfold absolute Capillary Number fingertip blood perfusion and clinical status in systemic sclerosis
The Journal of Rheumatology, 2016Co-Authors: A C Trombetta, Carmen Pizzorni, A Sulli, S Paolino, Vanessa Smith, B Ruaro, Maurizio CutoloAbstract:Objective. To quantify in patients with systemic sclerosis (SSc) the absolute nailfold Capillary Number/mm (the absolute Number of capillaries, observable in the first row, in 1 mm per field) and fingertip blood perfusion (FBP) during longterm therapy with the endothelin receptor antagonist bosentan (BOSE) and the synthetic analog of prostacyclin PGI2 iloprost (ILO) by multiple diagnostic tools. Observed values were correlated with clinical outcomes. Methods. Thirty patients with SSc already receiving intravenous ILO (80 μg/day) for 5 continuous days (every 3 mos) were recruited in the clinic. Fifteen patients continued such treatment (ILO group), while in 15 patients BOSE (125 mg twice/day) was added (ILO + BOSE group) because of the onset of pulmonary arterial hypertension or digital ulcers (DU). The followup period was 4 years (T0–T4). Every year the following were evaluated: absolute nailfold Capillary Number/mm by nailfold videocapillaroscopy, FBP by laser Doppler flowmetry, DU incidence, DLCO, systolic pulmonary arterial pressure (sPAP), renal arterial resistive index, and other biomarkers. From T2 to T4, laser speckled contrast analysis was added. Nonparametric tests were used for statistical analysis. Results. Limited to the ILO + BOSE group, absolute Capillary Number/mm and FBP showed a progressive increase independently from other variables. In addition, during followup there was a significant reduction (80%) in the incidence of new DU, whereas DLCO and sPAP did not worsen. Conclusion. The study shows in patients with SSc with up to 4 years of combined therapy a progressive significant recovery in structure and function of microvasculature linked to improved clinical outcomes, independent of disease severity.
A Sulli - One of the best experts on this subject based on the ideXlab platform.
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ab1133 automated assessment autocapi of nailfold Capillary Number versus manual counting in systemic sclerosispatients with different capillaroscopic patterns
Annals of the Rheumatic Diseases, 2019Co-Authors: Maurizio Cutolo, Carmen Pizzorni, Vanessa Smith, Amber Vanhaecke, M Pendolino, Massimo Patane, V Tomatis, A SulliAbstract:Background The nailfold videocapillaroscopy (NVC) analysis allows microvascular detection of possible markers of severity and progression in systemic sclerosis (SSc), as reduced Capillary Number, which has been associated with a high risk of developing disease complications (i.e. digital ulcers over time) (1-2). A recent study validated an automated counting system (AUTOCAPI) for the absolute nailfold Capillary Number in SSc patients by analysing the capillaroscopic images (3). Objectives To evaluate the performance of this automated software for absolute nailfold Capillary Number counting, in SSc patients with different NVC patterns of microangiopathy. Methods 183 random SSc patients collected at both Genova and Ghent Divisions of Rheumatology were enrolled (LeRoy 2001 or ACR 2013 criteria, mean age 55±13 year, mean disease duration 5.5±6.8 years) and classified by NVC in the following patterns: 28 ”not specific”, 37 “early”, 89 “active”, 29 “late”). 8 fingers for each patient were analysed, counting the Number of nailfold capillaries manually and by the AUTOCAPI software (DS Medica, Italy) along a millimetre in each finger image. The mean Capillary Number value of the eight finger images was calculated. The software reliability was assessed through calculation of the intraclass correlation coefficient (ICC) between automatic and manual counting. Results The mean Number of capillaries assessed by manual vs automatic counting was as follows: 5.23±1.7 vs 5.47±1.3 in the total group of SSc patients, 5.91±1.2 vs 6.87±1.2 in the ”not specific”, 7.23±1.4 vs 5.67±1.1 in the “early”, 4.67±1.1 vs 5.16±1.2 in the “active” and 3.72±1.5 vs 4.85±1.1 in the “late” pattern of microangiopathy. The higher standard deviation observed for automatic counting was 1.23 in the ”not specific” group. The following ICC’s were obtained respectively for total patients, ”not specific”, “early”, “active”, and “late” NVC patterns: 0.53, 0.51, 0.48, 0.50 and 0.66. The mean values for the manual versus automatic Capillary counting assessed by the two centres in all SSc patients were respectively: 5.92±1.8 and 5.02±1.1 for Genova centre, and 4.71±1.5 and 5.83±1.4 for Ghent centre. The automatic counting confirmed that Capillary Number progressively reduces from ”early” to ”active” to ”late” NVC pattern of microangiopathy in SSc. Conclusion This study reports for the first time the good reliability of AUTOCAPI software in nailfold Capillary Number counting in SSc patients with different patterns of microangiopathy. The use of automated counting software need to standardize nailfold Capillary assessment among different Rheumatological centres. References [1] Smith V, et al. J Rheumatol. 2013;40:2023-8. 2. Cutolo M, et al. Arthritis Rheumatol. 2016;68:2527-39. 3. Cutolo M, et al. Microcirculation. 2018;25:e12447. Disclosure of Interests None declared
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automated assessment of absolute nailfold Capillary Number on videocapillaroscopic images proof of principle and validation in systemic sclerosis
Microcirculation, 2018Co-Authors: Maurizio Cutolo, A C Trombetta, Karin Melsens, Carmen Pizzorni, A Sulli, Barbara Ruaro, S Paolino, Ellen Deschepper, Vanessa SmithAbstract:Background: Absolute nailfold Capillary Number should be a putative biomarker in selected rheumatic diseases but could be time-consuming and not highly repeatable. Objective: To validate an automated software for absolute nailfold Capillary Number and density evaluation, on NVC images in SSc. Methods: An automated software to count nailfold Capillary Number (AUTOCAPI) had been constructed, through an exploratory image set. Subsequently, application rules have been created to define the ROI in NVC images, through a training images set. The software reliability was assessed through calculation of the ICC between automatic and manual counting, by four independent observers, on the same NVC images. Results: The following ICC's were obtained per observer, for the patients with SSc (40 images), the healthy (20 images), and the PRP subgroups (20 images), respectively: 0.94, 0.81, and 0.62 (observer 1); 0.94, 0.91, and 0.67 (observer 2); 0.88, 0.56, and 0.64 (observer 3); and 0.88, 0.85, and 0.85 (observer 4). Conclusions: The validation of an automated software for measuring absolute nailfold Capillary Number and density in SSc was achieved. The integration into the pre-existing imaging software should make the assessment of the Capillary Number in NVC easier, quicker, and standardized.
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sat0377 reliability of a new automated system for absolute Capillary Number counting autocapi on systemic sclerosis nailfold videocapillaroscopic images
Annals of the Rheumatic Diseases, 2017Co-Authors: Maurizio Cutolo, A C Trombetta, Karin Melsens, Carmen Pizzorni, A Sulli, Ellen Deschepper, Vanessa SmithAbstract:Background Nailfold Capillary density is a useful measure in systemic sclerosis (SSc) classification and evaluation. Its manual detection may be time-consuming, hampering its use in largescale investigations. We evaluated a new automated system to assess the absolute nailfold Capillary Number. Objectives To attest the instrumental reliability of automatic counting in SSc patients using nailfold video capillaroscopy (NVC) images. Methods 75 NVC random images, from SSc patients, were blindly analyzed by four raters (2 less and 2 more experienced; raters: 1,2,3,4) from two European centers. Each rater was asked to define the region of interest (ROI) on the NVC images and to manually count the Number of capillaries, according to the following instructions: upper bound placed on top of the longest Capillary head and lower bound placed on half of the length of that longest Capillary (figure 1); if the common branch of an abnormal shape (neoangiogenesis) is in ROI it is counted as being one; if the common branch is out of ROI it is counted as separate capillaries; if the Capillary is on the edge of the vertical line of ROI, it is only counted when the head of the Capillary is half in ROI; if the Capillary head is on the edge of lower bound, it is counted as soon as the “head” part is in the ROI; all “heads” in the ROI are counted (not only distal row). The dedicated automated system (AUTOCAPI-ds medica, IT) also counted the Number of capillaries in the same ROI (figure 1). Reliability between the manual and automatic counting was investigated per rater through intraclass correlation coefficient (ICC) and reported with 95% confidence interval (CI). External validation was obtained by multi-rating of the same set of images. Average difference between automated and manual counting per rater was calculated. Results The ICC (95% CI) of manual versus automatic counting in ROI was 0.77 (0.61–0.86) for rater 1 (p Conclusions This is a first study to attest the reliability of a new automated system to calculate the absolute Number of capillaries in a ROI arising from SSc NVC images. High performance of the new automated counting system was confirmed in pathological conditions (SSc). Disclosure of Interest None declared
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effects of longterm treatment with bosentan and iloprost on nailfold absolute Capillary Number fingertip blood perfusion and clinical status in systemic sclerosis
The Journal of Rheumatology, 2016Co-Authors: A C Trombetta, Carmen Pizzorni, A Sulli, S Paolino, Vanessa Smith, B Ruaro, Maurizio CutoloAbstract:Objective. To quantify in patients with systemic sclerosis (SSc) the absolute nailfold Capillary Number/mm (the absolute Number of capillaries, observable in the first row, in 1 mm per field) and fingertip blood perfusion (FBP) during longterm therapy with the endothelin receptor antagonist bosentan (BOSE) and the synthetic analog of prostacyclin PGI2 iloprost (ILO) by multiple diagnostic tools. Observed values were correlated with clinical outcomes. Methods. Thirty patients with SSc already receiving intravenous ILO (80 μg/day) for 5 continuous days (every 3 mos) were recruited in the clinic. Fifteen patients continued such treatment (ILO group), while in 15 patients BOSE (125 mg twice/day) was added (ILO + BOSE group) because of the onset of pulmonary arterial hypertension or digital ulcers (DU). The followup period was 4 years (T0–T4). Every year the following were evaluated: absolute nailfold Capillary Number/mm by nailfold videocapillaroscopy, FBP by laser Doppler flowmetry, DU incidence, DLCO, systolic pulmonary arterial pressure (sPAP), renal arterial resistive index, and other biomarkers. From T2 to T4, laser speckled contrast analysis was added. Nonparametric tests were used for statistical analysis. Results. Limited to the ILO + BOSE group, absolute Capillary Number/mm and FBP showed a progressive increase independently from other variables. In addition, during followup there was a significant reduction (80%) in the incidence of new DU, whereas DLCO and sPAP did not worsen. Conclusion. The study shows in patients with SSc with up to 4 years of combined therapy a progressive significant recovery in structure and function of microvasculature linked to improved clinical outcomes, independent of disease severity.
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Capillary Number correlations for two phase flow in porous media
Physical Review E, 2020Co-Authors: R HilferAbstract:Relative permeabilities and Capillary Number correlations are widely used for quantitative estimates of enhanced water flood performance in porous media. They enter as essential parameters into reservoir simulations. Experimental Capillary Number correlations for seven different reservoir rocks and 21 pairs of wetting and nonwetting fluids are analyzed. The analysis introduces generalized local macroscopic Capillary Number correlations. It eliminates shortcomings of conventional Capillary Number correlations. Surprisingly, the use of Capillary Number correlations on reservoir scales may become inconsistent in the sense that the limits of applicability of the underlying generalized Darcy law are violated. The results show that local macroscopic Capillary Number correlations can distinguish between rock types. The experimental correlations are ordered systematically using a three-parameter fit function combined with a novel fluid pair based figure of merit.
