A novel perimeter-based index for evaluating the similarity of structure contours

AbstractIntroductionThe authors proposed a novel perimeter-based index (PBI) that was capable of evaluating the accuracy in the appraisal of auto-segmentation software. A quantitative value, that is time saved in editing the auto-segmented contours, was used to compare the effectiveness of two other commonly used indices in this study.MethodsThe relationship between the proposed index and the amount of the contouring time that could be saved was studied. The performances of two other commonly used similarity indices, namely Dice similarity coefficient (DSC) and the modified normalised average Hausdorff distance (MNAHD), were also evaluated. Ten nasopharyngeal cases and ten prostate cases that were previously treated with intensity-modulated radiation therapy technique were recruited as the validation cases in this study. Three observers were invited to contour four structures (bladder, rectum, brain stem and parotid gland) on computed tomography images of the validation cases without any aids. The time taken for contouring was recorded as the manual contouring time. By using an atlas-based auto-segmentation software, three sets of contours were generated for each validation case with different library sizes to produce different degrees of similarity level. The values of the three similarity indices of the auto-segmented contours were calculated. The observers were asked to edit the auto-segmented contours and the editing time was recorded.The correlation between the editing time and the similarity indices was studied. The amount of time saved was calculated by subtracting the editing time from the manual contouring time. The performances of PBI, DSC and MNAHD were evaluated using Pearson correlation coefficient and receiver operating curve (ROC) analysis.ResultsThe PBI showed a positive linear relationship with the amount of contouring time saved. Pearson correlation coefficient ranged from 0·73 to 0·86 for the four structures. The PBI had a stronger correlation than the DSC in bladder and parotid gland, while there was no significant difference between the two indices in rectum and brain stem. The MNAHD had an inferior correlation than the proposed index. For the ROC analysis, the cut-off values for the PBI were 0·549, 0·401 and 0·301 for the three levels of contouring time saved, namely 50, 25 and 0%, respectively. The accuracy of PBI was over 77% and the Youden index was >0·6 for all three levels.ConclusionsThe proposed index showed a stronger relationship to the amount of contouring time saved. It was a simple tool that could be used to evaluate the performance of different segmentation algorithms.

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Translation and validation of the Italian Version of the User Version of the Mobile Application Rating Scale (uMARS): questionnaire validation study (Preprint)

10.2196/preprints.24427 ◽

2020 ◽

Author(s):

Simone Morselli ◽

Alexander Domnich ◽

Arcangelo Sebastianelli ◽

Chiara Bucchi ◽

Pietro Spatafora ◽

...

Keyword(s):

Correlation Coefficient ◽

Mobile Application ◽

Rating Scale ◽

Pearson Correlation ◽

T Test ◽

Pearson Correlation Coefficient ◽

Cronbach’S Alpha ◽

Cronbach's Alpha ◽

Significant Difference ◽

Paired T Test

BACKGROUND Health sciences are steadily developing apps to help people to have a correct lifestyle and, in case of chronic diseases, to help physicians to follow their patients. However, a proper validated tool to evaluate patients’ perception of apps’ usefulness, graphic and comfort to use it still lacks in many languages. At present time, there is an English validated questionnaire called User Version of the Mobile Application Rating Scale (uMARS). OBJECTIVE Aim of the study is to translate and validate uMARS in Italian. METHODS uMARS questionnaire have been translated into Italian by an official translator from English. Then, questionnaire has been administrated to 100 smartphone users to evaluate the same App at time 0 and at time 1 (after 2 weeks). Paired t test, Pearson Correlation Coefficient,Intraclass Correlation Coefficient (ICCs) and Cronbach’s Alpha were used to evaluate Italian uMARS reliability and validity. RESULTS Subjects were 100, 52 male (52%) and 48 females (48%). Mean age was 22.8 (SD: 3.4). All the enrolled subjects answered to all questions both at time 0 and at time 1. Paired t test showed no statistically significant difference for each answer or answers group between time 0 and 1 (P>0.05). In detail, higher variability was observed for question E20, regarding the subjective evaluation of the app: “What is your overall (star) rating of the app?” T0 mean 3.7 (SD: 0.8) vs T1 mean 3.6 (SD:1.0) p=0.089. The lower variability was observed in the Information Section for question D16 “Credibility of source: does the information within the app seem to come from a credible source? “, T0 mean 3.6 (SD:1.1) T1 mean 3.6 (SD: 1.1) p=1.000. Cronbach’s alpha was 0.945, as all patients answered to all questions. Each question was furtherly assessed through Pearson correlation coefficient, which demonstrated high reliability, with significant P (<0.05) and Pearson Coefficients higher than 0.7. Similarly, ICC, which was always higher than 0.750, confirmed an excellent test-rest reliability. CONCLUSIONS Our results allow the validation of uMARS in Italian language and it may become a reliable and useful tool to evaluate health app

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An Analysis of Malar Fat Volume in Two Age Groups: Implications for Craniofacial Surgery

Craniomaxillofacial Trauma & Reconstruction ◽

10.1055/s-0032-1329545 ◽

2012 ◽

Vol 5 (4) ◽

pp. 231-234 ◽

Cited By ~ 5

Author(s):

Christina L. Corey ◽

Gerald R. Popelka ◽

Jose E. Barrera ◽

Sam P. Most

Keyword(s):

Correlation Coefficient ◽

Spin Echo ◽

Pearson Correlation ◽

Age Groups ◽

Pearson Correlation Coefficient ◽

Spin Echo Sequence ◽

Significant Difference ◽

Analysis Application ◽

Fat Volume ◽

Two Age Groups

Objective To evaluate how malar fat pad (MFP) volumes vary with age, after controlling for gender and body mass index (BMI). Study Design A prospective case–control study evaluating volume of the MFP in women of two age groups. Methods Soft tissue dimensions were measured in eight subjects using magnetic resonance imaging. A multiplanar localizing sequence, followed in sagittal and coronal orientations using a turbo spin echo sequence, was performed to define the MFP. Volumetric calculations were then performed using a 3D image analysis application (Dextroscope, Volume Interactions, Republic of Singapore) to circumscribe areas, orient dimensions, and calculate volumes of the MFP. Results These data reveal no significant difference in the mean (standard deviation) right MFP ( p = 0.50), left MFP ( p = 0.41), or total MFP ( p = 0.45) volumes when comparing the two age groups. In addition, these data indicate that there was no correlation between age and total MFP volume (Pearson correlation coefficient 0.27). Moreover, there was no correlation between age and the ratio of total volume/BMI (Pearson correlation coefficient −0.18). Conclusions Although the sample size of this study was small, these data indicate that ptosis of midfacial fat is more important than volume loss in midfacial aging. These data would suggest repositioning as the primary modality for craniofacial reconstruction.

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On the Psychological Reality of the Pearson Correlation Coefficient: Effects of Objective Covariation on Subjective Estimates

PsycEXTRA Dataset ◽

10.1037/e537052012-416 ◽

2004 ◽

Author(s):

Richard B. Anderson ◽

Andrea M. Angott ◽

Michael E. Doherty

Keyword(s):

Correlation Coefficient ◽

Pearson Correlation ◽

Pearson Correlation Coefficient ◽

Psychological Reality ◽

Subjective Estimates

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Relationship between Invasive and Non-Invasive Hemodynamic Measures in Experimental Pulmonary Hypertension

Current Respiratory Medicine Reviews ◽

10.2174/1573398x16666200516180118 ◽

2020 ◽

Vol 16 (1) ◽

pp. 47-53

Author(s):

Vicente Benavides-Córdoba ◽

Mauricio Palacios Gómez

Keyword(s):

Heart Rate ◽

Pulmonary Hypertension ◽

Ejection Fraction ◽

Right Ventricle ◽

Correlation Coefficient ◽

Pearson Correlation ◽

Systolic Pressure ◽

Control Group ◽

Pearson Correlation Coefficient ◽

Non Invasive

Introduction: Animal models have been used to understand the pathophysiology of pulmonary hypertension, to describe the mechanisms of action and to evaluate promising active ingredients. The monocrotaline-induced pulmonary hypertension model is the most used animal model. In this model, invasive and non-invasive hemodynamic variables that resemble human measurements have been used. Aim: To define if non-invasive variables can predict hemodynamic measures in the monocrotaline-induced pulmonary hypertension model. Materials and Methods: Twenty 6-week old male Wistar rats weighing between 250-300g from the bioterium of the Universidad del Valle (Cali - Colombia) were used in order to establish that the relationships between invasive and non-invasive variables are sustained in different conditions (healthy, hypertrophy and treated). The animals were organized into three groups, a control group who was given 0.9% saline solution subcutaneously (sc), a group with pulmonary hypertension induced with a single subcutaneous dose of Monocrotaline 30 mg/kg, and a group with pulmonary hypertension with 30 mg/kg of monocrotaline treated with Sildenafil. Right ventricle ejection fraction, heart rate, right ventricle systolic pressure and the extent of hypertrophy were measured. The functional relation between any two variables was evaluated by the Pearson correlation coefficient. Results: It was found that all correlations were statistically significant (p <0.01). The strongest correlation was the inverse one between the RVEF and the Fulton index (r = -0.82). The Fulton index also had a strong correlation with the RVSP (r = 0.79). The Pearson correlation coefficient between the RVEF and the RVSP was -0.81, meaning that the higher the systolic pressure in the right ventricle, the lower the ejection fraction value. Heart rate was significantly correlated to the other three variables studied, although with relatively low correlation. Conclusion: The correlations obtained in this study indicate that the parameters evaluated in the research related to experimental pulmonary hypertension correlate adequately and that the measurements that are currently made are adequate and consistent with each other, that is, they have good predictive capacity.

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Bed-Based Ballistocardiography: Dataset and Ability to Track Cardiovascular Parameters

Sensors ◽

10.3390/s21010156 ◽

2020 ◽

Vol 21 (1) ◽

pp. 156

Author(s):

Charles Carlson ◽

Vanessa-Rose Turpin ◽

Ahmad Suliman ◽

Carl Ade ◽

Steve Warren ◽

...

Keyword(s):

Blood Pressure ◽

Stroke Volume ◽

Systolic Blood Pressure ◽

Correlation Coefficient ◽

Pearson Correlation ◽

Health Assessment ◽

Initial Study ◽

Pearson Correlation Coefficient ◽

Medical Systems ◽

Cardiovascular Parameters

Background: The goal of this work was to create a sharable dataset of heart-driven signals, including ballistocardiograms (BCGs) and time-aligned electrocardiograms (ECGs), photoplethysmograms (PPGs), and blood pressure waveforms. Methods: A custom, bed-based ballistocardiographic system is described in detail. Affiliated cardiopulmonary signals are acquired using a GE Datex CardioCap 5 patient monitor (which collects ECG and PPG data) and a Finapres Medical Systems Finometer PRO (which provides continuous reconstructed brachial artery pressure waveforms and derived cardiovascular parameters). Results: Data were collected from 40 participants, 4 of whom had been or were currently diagnosed with a heart condition at the time they enrolled in the study. An investigation revealed that features extracted from a BCG could be used to track changes in systolic blood pressure (Pearson correlation coefficient of 0.54 +/− 0.15), dP/dtmax (Pearson correlation coefficient of 0.51 +/− 0.18), and stroke volume (Pearson correlation coefficient of 0.54 +/− 0.17). Conclusion: A collection of synchronized, heart-driven signals, including BCGs, ECGs, PPGs, and blood pressure waveforms, was acquired and made publicly available. An initial study indicated that bed-based ballistocardiography can be used to track beat-to-beat changes in systolic blood pressure and stroke volume. Significance: To the best of the authors’ knowledge, no other database that includes time-aligned ECG, PPG, BCG, and continuous blood pressure data is available to the public. This dataset could be used by other researchers for algorithm testing and development in this fast-growing field of health assessment, without requiring these individuals to invest considerable time and resources into hardware development and data collection.

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Assessment of the Dissimilarities of EDI and SPI Measures for Drought Determination in South Africa

Water ◽

10.3390/w13010082 ◽

2021 ◽

Vol 13 (1) ◽

pp. 82

Author(s):

Omolola M. Adisa ◽

Muthoni Masinde ◽

Joel O. Botai

Keyword(s):

South Africa ◽

South African ◽

Correlation Coefficient ◽

Pearson Correlation ◽

Standardized Precipitation Index ◽

Drought Monitoring ◽

Drought Indices ◽

Drought Severity ◽

Pearson Correlation Coefficient ◽

Drought Duration

This study examines the (dis)similarity of two commonly used indices Standardized Precipitation Index (SPI) computed over accumulation periods 1-month, 3-month, 6-month, and 12-month (hereafter SPI-1, SPI-3, SPI-6, and SPI-12, respectively) and Effective Drought Index (EDI). The analysis is based on two drought monitoring indicators (derived from SPI and EDI), namely, the Drought Duration (DD) and Drought Severity (DS) across the 93 South African Weather Service’s delineated rainfall districts over South Africa from 1980 to 2019. In the study, the Pearson correlation coefficient dissimilarity and periodogram dissimilarity estimates were used. The results indicate a positive correlation for the Pearson correlation coefficient dissimilarity and a positive value for periodogram of dissimilarity in both the DD and DS. With the Pearson correlation coefficient dissimilarity, the study demonstrates that the values of the SPI-1/EDI pair and the SPI-3/EDI pair exhibit the highest similar values for DD, while the SPI-6/EDI pair shows the highest similar values for DS. Moreover, dissimilarities are more obvious in SPI-12/EDI pair for DD and DS. When a periodogram of dissimilarity is used, the values of the SPI-1/EDI pair and SPI-6/EDI pair exhibit the highest similar values for DD, while SPI-1/EDI displayed the highest similar values for DS. Overall, the two measures show that the highest similarity is obtained in the SPI-1/EDI pair for DS. The results obtainable in this study contribute towards an in-depth knowledge of deviation between the EDI and SPI values for South Africa, depicting that these two drought indices values are replaceable in some rainfall districts of South Africa for drought monitoring and prediction, and this is a step towards the selection of the appropriate drought indices.

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Fault Detection and Location Method for Mesh-type DC Microgrid using Pearson Correlation Coefficient

IEEE Transactions on Power Delivery ◽

10.1109/tpwrd.2020.3008924 ◽

2020 ◽

pp. 1-1 ◽

Cited By ~ 1

Author(s):

Liang Kong ◽

Heng Nian

Keyword(s):

Fault Detection ◽

Correlation Coefficient ◽

Pearson Correlation ◽

Pearson Correlation Coefficient ◽

Dc Microgrid ◽

Location Method

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Use of Multiple Visits to Increase Blood Pressure Tracking Correlations in Childhood

PEDIATRICS ◽

10.1542/peds.87.5.708 ◽

1991 ◽

Vol 87 (5) ◽

pp. 708-711

Author(s):

Matthew W. Gillman ◽

Bernard Rosner ◽

Denis A. Evans ◽

Laurel A. Smith ◽

James O. Taylor ◽

...

Keyword(s):

Blood Pressure ◽

Diastolic Blood Pressure ◽

Correlation Coefficient ◽

Diastolic Pressure ◽

Pearson Correlation ◽

Systolic Pressure ◽

Pearson Correlation Coefficient ◽

Increase Blood Pressure ◽

Multiple Visit

Previous studies of childhood blood pressure have shown tracking correlations, which estimate the magnitude of association between initial and subsequent measurements, to be lower than corresponding adult values. Inasmuch as this disparity could arise from failing to account for a larger week-to-week variability in children, blood pressure was measured for 4 successive years, on four weekly visits in each year, and with three measurements at each visit, using a random-zero sphygmomanometer, in a cohort of 333 schoolchildren aged 8 through 15 at entry. Ninety percent of subjects had measurements in 1 or more years of follow-up. For all follow-up periods (1, 2, and 3 years from baseline), the Pearson correlation coefficient (r) for both systolic and diastolic blood pressure rose substantially with the number of weekly visits used to calculate each subject's yearly blood pressure (P < .0001). For systolic pressure, the 3-year r values for 1, 2, 3, and 4 visits were .45, .55, .64, and .69, respectively. For diastolic pressure (Korotkoff phase 4), the corresponding values were .28, .41, .47, and .54. These higher multiple-visit estimates of tracking approximate published adult values and raise the possibility that prediction of adult blood pressure from childhood measurements may be improved by averaging readings from multiple weekly visits.

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