scholarly journals Clinical validation of time reduction strategy in continuous step-and-shoot mode during SPECT acquisition

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Valentin Picone ◽  
Nikolaos Makris ◽  
Fanny Boutevin ◽  
Sarah Roy ◽  
Margot Playe ◽  
...  
Keyword(s):  
Image Quality ◽  
Head Rotation ◽  
Visual Assessment ◽  
Motion Artifacts ◽  
Altman Analysis ◽  
Bland Altman Analysis ◽  
Focal Uptake ◽  
Significant Difference ◽  
Lung Scan ◽  
Step And Shoot

Abstract Background The SwiftScan solution (General Electric Healthcare) combines a new low-energy high-resolution sensitivity collimator and a tomographic step-and-shoot continuous (SSC) mode acquisition. The purpose of this study is to determine whether SSC mode can be used in clinical practice with shorter examination times, while preserving image quality and ensuring accurate semi-quantification. Twenty bone scan and 10 lung scan studies were randomly selected over a period of 2 months. Three sets of image datasets were produced: step-and-shoot (SS) acquisition, simulated 25% count reduction using the Poisson resampling method (SimSS), and SimSS continuous acquisition (SimSSC), where SimSS was summed with counts acquired during detector head rotation. Visual assessment (5-point Likert scale, 2 readers) and semi-quantitative evaluation (50 focal uptake from 10 bone studies), assessed by SUVmean, coefficient of variation (COV), and contrast-to-noise ratio (CNR), were performed using t test and Bland-Altman analysis. Results Intra-reader agreement was substantial for reader 1 (k = 0.71) and for reader 2 (k = 0.61). Inter-reader agreement was substantial for SS set (k = 0.93) and moderate for SimSSC (k = 0.52). Bland-Altman analysis showed a good interchangeability of SS and SimSSC SUV values. The mean CNR between SS and SimSSC was not significantly different: 42.9 ± 43.7 [23.7–62.1] vs. 43.1 ± 46 [22.9–63.3] (p = 0.46), respectively. COV values, assessing noise level, did not deviate significantly between SS and SimSSC: 0.20 ± 0.08 [0.18–0.23] vs. 0.21 ± 0.08, [0.18–0.23] (p = 0.15), respectively, whereas a significant difference was demonstrated between SS and SimSS: 0.20 ± 0.08 [0.18–0.23] vs. 0.23 ± 0.09 [0.20–0.25] (p < 0.0001), respectively. Conclusions SSC mode acquisition decreases examination time by approximately 25% in bone and lung SPECT/CT studies compared to SS mode (~ 2 min per single-bed SPECT), without compromising image quality and signal quantification. This SPECT sensitivity improvement also offers the prospect of more comfortable exams, with less motion artifacts, especially in painful or dyspneic patients.

scholarly journals Comparison of IOP Measurement by Goldmann Applanation Tonometer, ICare Rebound Tonometer, and Tono-Pen in Keratoconus Patients after MyoRing Implantation

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Mahmoud Rateb ◽  
Mahmoud Abdel-Radi ◽  
Zeiad Eldaly ◽  
Mohamed Nagy Elmohamady ◽  
Asaad Noor El Din
Keyword(s):  
Central Corneal Thickness ◽  
Pearson Correlation ◽  
Corneal Thickness ◽  
Altman Analysis ◽  
Bland Altman Analysis ◽  
Rebound Tonometer ◽  
Goldmann Applanation Tonometer ◽  
Significant Difference ◽  
Applanation Tonometer ◽  
Icare Rebound Tonometer

Purpose. To evaluate the different IOP readings by Goldmann applanation tonometer (GAT), ICare rebound tonometer, and Tono-Pen in keratoconus patients after MyoRing implantation. To assess the influence of central corneal thickness (CCT) and thinnest corneal location (TCL) on IOP measurements by different tonometers. Setting. Prospective observational study was conducted in two private centers in Egypt from February 2015 to November 2016. Methods. Seventeen eyes of 10 patients suffering from keratoconus and who underwent MyoRing implantation were recruited. All subjects underwent GAT, ICare, and Tono-Pen IOP measurements in random order. Central corneal thickness and thinnest corneal location were assessed by Pentacam. Difference in mean in IOP readings was assessed by T-test. Correlation between each pair of devices was evaluated by Pearson correlation coefficient. The Bland–Altman analysis was used to assess intertonometer agreement. Results. Seventeen eyes (10 patients) were evaluated. The mean IOP reading was 13.9 ± 3.68, 12.41 ± 2.87, and 14.29 ± 1.31 mmHg in GAT, ICare, and Tono-Pen group, respectively. There was a significant difference between IOP readings by GAT/ICare and Tono-Pen/ICare (p value: 0.032 and 0.002, respectively) with no significant difference between GAT/Tono-Pen (p value: 0.554). Mean difference in IOP measurements between GAT/ICare was 1.49 ± 2.61 mmHg, Tono-Pen/ICare was 1.89 ± 2.15 mmHg, and GAT/Tono-Pen was −0.39 ± 2.59 mmHg. There was no significant correlation between the difference in IOP readings among any pair of devices and CCC or TCL. The Bland–Altman analysis showed a reasonable agreement between any pair of tonometers.

Validation of the visual acuity iPad app Eye Chart Pro compared to the standard Early Treatment Diabetic Retinopathy Study chart in a low-vision population

2020 ◽  
pp. 1357633X2096064
Author(s):  
Hassan Hazari ◽  
Rachel Curtis ◽  
Karen Eden ◽  
Wilma M Hopman ◽  
Isabella Irrcher ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Diabetic Retinopathy ◽  
Early Treatment ◽  
Low Vision ◽  
Test Methods ◽  
Absolute Difference ◽  
Altman Analysis ◽  
Bland Altman Analysis ◽  
Significant Difference ◽  
Ipad App

Introduction A low-vision assessment (LVA) is central to developing a vision rehabilitation plan. However, access to LVAs is often limited by the quantity and geographic distribution of low-vision providers, as well as patient-centred transportation challenges. A tablet-based LVA tool kit, delivered virtually, has the potential to overcome many of these barriers. The purpose of this research was to validate a key component of the tablet-based tool kit – a commercially available iPad visual acuity (VA) test (Eye Chart Pro) iPad app – in a low-vision population. Methods Participants with low vision ( n = 26) and those who were normally sighted ( n = 25) underwent VA testing with both the iPad VA test application and the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. The VA data were compared using a t-test, linear regression and Bland–Altman analysis. Results There was no significant difference in the mean absolute difference in VA (log of minimum angle of resolution (logMAR)=0.11; p = 0.82). Eye Chart Pro and Standard ETDRS Chart measures were also not significantly different ( p = 0.98). However, there were significant differences between test methods in the low-vision group and the normally sighted group ( p > 0.0001 and p = 0.007, respectively). The Bland–Altman analysis showed a mean bias (difference) of –0.0005 logMAR between methods, and 95% limits of agreement of 0.298 and –0.299 logMAR. Discussion The ETDRS chart function on the Eye Chart Pro application can reliably measure VA across a range, from normally sighted patients to those with low vision.

scholarly journals Comparison between optical and digital blur using near visual acuity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
David Kordek ◽  
Laura K. Young ◽  
Jan Kremláček
Keyword(s):  
Visual Acuity ◽  
Refractive Error ◽  
Low Cost ◽  
Pairwise Comparison ◽  
Clinical Population ◽  
Altman Analysis ◽  
Bland Altman Analysis ◽  
Laboratory Setup ◽  
Significant Difference ◽  
Near Visual Acuity

AbstractIn a low-cost laboratory setup, we compared visual acuity (VA) for stimuli rendered with Zernike aberrations to an equivalent optical dioptric defocus in emmetropic individuals using a relatively short observing distance of 60 cm. The equivalent spherical refractive error of + 1, + 2 or + 4 D, was applied in the rendering of Landolt Rings. Separately, the refractive error was introduced dioptrically in: (1) unchanged Landolt Rings with an added external lens (+ 1, + 2 or + 4 D) at the subject's eye; (2) same as (1) but with an added accommodation and a vertex distance adjustment. To compare all three approaches, we examined VA in 10 healthy men. Stimuli were observed on a PC CRT screen. For all three levels of refractive error, the pairwise comparison did not show a statistically significant difference between digital blur and accommodation-plus-vertex-distance-adjusted dioptric blur (p < 0.204). The best agreement, determined by Bland–Altman analysis, was measured for + 4 D and was in line with test–retest limits for examination in the clinical population. Our results show that even for a near observing distance, it is possible to use digitally rendered defocus to replicate dioptric blur without a significant change in VA in emmetropic subjects.

scholarly journals Heart Transplant Patients in a wide population observed for Mycophenolic Acid Area Under The Curve executed with a limited sampling strategy technique

2021 ◽  
Author(s):  
Francesco Lo Re ◽  
Sandro Sponga ◽  
Chiara Nalli ◽  
Antonella Zucchetto ◽  
Ugolino Livi ◽  
...  
Keyword(s):  
Linear Regression ◽  
Heart Transplant ◽  
Mycophenolic Acid ◽  
Sampling Strategy ◽  
Limited Sampling Strategy ◽  
Altman Analysis ◽  
Bland Altman Analysis ◽  
Limited Sampling ◽  
Standard Clinical Practice ◽  
Significant Difference

Aim The study aim is the validation of two algorithms of Limited Sampling Strategy (LSS) for the quantification of Mycophenolic Acid (MPA) Area under the plasma concentration-time curve from 0 to 12h (AUC0-12h) in a cohort of non-selected Heart Transplant (HTx) recipients treated, as standard clinical practice, with Mycophenolate Mofetil (MMF) combined with Cyclosporine (CsA), or Tacrolimus (TAC). These two LSSs were previously tested and validated by Baraldo et al. in a cohort of selected HTx recipients 1,2. The value of MPA AUC0-12h (real and estimated with LSSs) among non-rejected (NR) and rejected (R) patients were evaluated. Methods Linear regression and Bland Altman Analysis validated two LSSs methods (named LSS3 and LSS4 by number of blood samples used). The value of MPA AUC0-12h between NR and R patients were compared by Mann-Whitney test. Results The validation reports positive results for LSS3 and LSS4 according to linear regression (r=0.91 and 0.94 and R2=0.84 and 0.88, respectively) and Bland Altman Analysis (p=0.04 and 0.04). There was a difference of borderline statistically significance (p=0.06) for the median value of MPA AUC0-12h (mg×h/L) between NR and R patients (46.60; Interquartile Range (IQR): 34.80-64.10 vs 33.70; IQR: 23.60-48.25); whereas the difference was statistically significant for both LSS3 and LSS4 (p=0.03 and 0.04). Conclusion The capability of these two LSSs to estimate MPA AUC0-12h in cohort of non-selected HTx recipients and the suggestion of a significant difference on MPA AUC0-12h between NR and R patients, confirm the importance of MPA quantification in the clinical field.

scholarly journals Optimization Image Quality of Knee MRI Sagital Plane T2 Weighted TSE Sequences with Variations of Echo Train Length (ETL) on Cartesian and Blade Technique

2020 ◽  
Vol 202 ◽  
pp. 15015
Author(s):  
Rini Indrati ◽  
Dwi Rochmayanti ◽  
Heny Rubiyanti ◽  
Donny Susilawardhono ◽  
Siti Daryati ◽  
...  
Keyword(s):  
Image Quality ◽  
Motion Artifact ◽  
Motion Artifacts ◽  
Wilcoxon Test ◽  
P Value ◽  
Scanning Time ◽  
Knee Mri ◽  
Significant Difference ◽  
Train Length ◽  
Anatomical Information

The use of Cartesian and Blade techniques also affects image quality. The Cartesian technique is more commonly used in Knee MRI examinations. Cartesian technique is vulnerable to movement, giving rise to motion artifacts. This motion artifact is often caused by too long scanning time, so ETL settings are important. An alternative to reducing this risk is to use the Blade technique and by setting the appropriate ETL. The research objective was to determine the differences image quality and anatomical information and to determine the technique that produced quality images and MRI anatomical information on the sagittal knee section between the Cartesian ETL and Blade T2 Weighted TSE combination. This is experiment research. Samples of 10 volunteers, carried out scanning with Cartesian and Blade techniques with variations ETL 14, 16, 18. Focus of assessment on ACL, PCL, meniscus, fluid, and fat. Image quality includes SNR and CNR. The assessment of the anatomical information by a radiologist. Data analyzed with Anova, Friedman, and Wilcoxon test. The results study showed that overall, there are significant differences in image quality between Cartesian and Blade techniques with p-value 0.005. There are differences in anatomical information with p-value <0.001. The best technique from image quality (SNR and CNR) is Cartesian-ETL 14 and based on anatomical information, the best technique is using Blade-ETL 14. Image quality in the two techniques with ETL 14 there is no significant difference with p-value of 0.414, so that Cartesian and Blade-ETL 14 settings produce the same image quality.

scholarly journals Comparison of B-Mode with B-Flow Sonography for the Evaluation of Femoral Arteries in Infants

2017 ◽  
Vol 189 (12) ◽  
pp. 1161-1167 ◽  
Author(s):  
Michael Groth ◽  
Elena Dammann ◽  
Florian Arndt ◽  
Marielle Ernst ◽  
Jochen Herrmann
Keyword(s):  
Image Quality ◽  
Intraclass Correlation ◽  
Visual Image ◽  
Vessel Diameter ◽  
Altman Analysis ◽  
Exact Test ◽  
Bland Altman Analysis ◽  
Femoral Arteries ◽  
Key Points ◽  
Superior Image Quality

Purpose To evaluate femoral arteries (FAs) in infants in the context of catheter angiography with B-mode (BMS) and B-flow sonography (BFS) and to compare both methods for vessel delineation and reliability of vessel diameter measurements. Methods 21 consecutive infants who underwent ultrasound for the evaluation of FAs before or after cardiac catheterization were retrospectively included in this study. The diameter of the FAs and the maximum length of the vessel section displayed on a single ultrasound plane were recorded by two radiologists for BMS and BFS. The visual image quality was rated by one observer. Statistics included intraclass correlation coefficient, Bland-Altman analysis, Fisher´s exact test and t-test. Results The intraobserver as well as interobserver correlation was excellent for BMS (0.7922 and 0.6521) and BFS (0.8094 and 0.7637). The Bland-Altman analysis revealed limits of agreement for BMS between +/–0.73 mm (intraobserver) and +/–0.55 mm (interobserver) and for BFS between +/–0.83 mm (intraobserver) and +/–0.7 mm (interobserver). BFS allowed visualization of a longer stretch of the FA than BMS (length 3.54 +/–0.85 vs. 2.21 +/–0.9 cm, p < 0.0001). The image quality was significantly higher for BFS (p = 0.0043). Conclusion Since BFS shows excellent reproducibility for vessel measurements and superior image quality in infants, if available, BFS should be included in standard protocols when realistic measurements are required. Key Points  Citation Format

scholarly journals Validity and Reliability of the GymAware Linear Position Transducer for Squat Jump and Counter-Movement Jump Height

Sports ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 177 ◽  
Author(s):  
Tanuj Wadhi ◽  
Jacob Rauch ◽  
Nauris Tamulevicius ◽  
Jody Andersen ◽  
Eduardo De Souza
Keyword(s):  
Test Validity ◽  
Jump Height ◽  
Altman Analysis ◽  
Squat Jump ◽  
Retest Reliability ◽  
Bland Altman Analysis ◽  
Position Transducer ◽  
Counter Movement Jump ◽  
Significant Difference ◽  
Test Retest Reliability

The purpose of this study was to assess the concurrent validity and test-retest reliability of a linear position transducer (LPT) for the squat jump (SJ) and counter-movement jump (CMJ) height. Twenty-eight subjects (25.18 ± 7.1 years) performed three SJs followed by three CMJs using a force plate concurrently with the LPT to test validity. Subjects returned on a separate day, at least 48 h apart, to measure test-retest reliability. A t-test showed a significant difference between the two devices for both SJ (p < 0.001) and CMJ (p < 0.001) while Bland–Altman analysis for validity revealed that the LPT overestimated jump height for both SJ (mean difference (MD) = 8.01 ± 2.93 cm) and CMJ (MD = 8.68 ± 2.99 cm). With regards to reliability of the LPT, mean intraclass correlation (ICC) for both SJ (ICC = 0.84) and CMJ (ICC = 0.95) were high, and Bland–Altman analysis showed mean differences lower than minimal detectable change (MDC) between the days for both SJ (MD = 1.89 ± 4.16 cm vs. MDC = 2.72 cm) and CMJ (MD = 0.47 ± 3.23 cm vs. MDC = 2.11 cm). Additionally, there was a low coefficient of variation (CV) between days for both SJ (CV = 3.25%) and CMJ (CV = 0.74%). Therefore, while the LPT overestimates jump height, it is a reliable tool for tracking changes in jump height to measure performance improvement and monitor fatigue.

Anomalous Aortic Origin of a Coronary Artery: Symptoms Do Not Correlate With Intramural Length or Ostial Diameter

2017 ◽  
Vol 8 (4) ◽  
pp. 445-452 ◽  
Author(s):  
Shyamasundar Balasubramanya ◽  
Michael C. Mongé ◽  
Osama M. Eltayeb ◽  
Anne E. Sarwark ◽  
John M. Costello ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Surgical Repair ◽  
Preoperative Imaging ◽  
Altman Analysis ◽  
Resonance Imaging ◽  
Surgical Indications ◽  
Bland Altman Analysis ◽  
Significant Difference ◽  
Magnetic Resonance Imaging Mri ◽  
Strong Agreement

Background: Anomalous aortic origin of a coronary artery (AAOCA) is a known cause of sudden death. Our hypothesis was that longer intramural length and smaller ostial diameter correlate with preoperative symptoms. If true, this would assist in the decision for surgical indications. We also assessed the accuracy of preoperative imaging to predict intramural length. Methods: Retrospective analysis of patients who underwent AAOCA unroofing from 2006 to 2014. Patients had preoperative computed tomography angiography (CTA) or magnetic resonance imaging (MRI). Intramural length was measured. Intramural lengths and ostial diameters were also measured intraoperatively (operating room [OR]). Symptoms were noted. Intramural lengths and ostial diameters were compared between patients with and without preoperative symptoms. The accuracy of intramural length measured by CTA/MRI versus the length measured in the OR was assessed using a Bland-Altman analysis. Results: Sixty-six patients underwent surgical repair of AAOCA. Fifty-two (79%) patients were symptomatic and 14 (21%) were asymptomatic. Mean age was 12.4 ± 4.0 years. There was no mortality. There was strong agreement between intramural length measured by CTA/MRI and measured in the OR. There was no significant difference in AAOCA intramural length in the symptomatic (8.6 ± 3.5 mm) and asymptomatic (8.9 ± 2.8 mm, P = .77) patients, which were measured both by CTA/MRI and intraoperatively (symptomatic 7.3 ± 2.5 mm, asymptomatic 6.9 ± 2.8 mm; P = .62). There was also no significant difference in AAOCA ostial diameters between groups (symptomatic = 1.9 ± 0.5 mm, asymptomatic = 1.6 ± 0.5 mm; P = .09). Conclusion: Preoperative CTA/MRI was very accurate in predicting the length of surgical unroofing. There was no demonstrable correlation between preoperative symptoms and intramural AAOCA length or AAOCA ostial diameter.

scholarly journals P1088BRAND NEW METHOD TO CALCULATE THE VOLUME OF EXTRA CELLULAR FLUID IN HEMODIALYSIS PATIENT ONLY FROM REGULAR BLOOD TEST

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Kazuhiko Shibata ◽  
Shigeru Nakai ◽  
Ikuto Masakane ◽  
Takahito Ito ◽  
Kiyoshi Ozawa ◽  
...  
Keyword(s):  
Uric Acid ◽  
Blood Test ◽  
Cell Membranes ◽  
Impedance Method ◽  
Hydration Status ◽  
Altman Analysis ◽  
Simple Diffusion ◽  
Bland Altman Analysis ◽  
Significant Difference ◽  
Pass Through

Abstract Background and Aims Uric acid is a small molecule with molecular weight 168, but has an electrical pole which enables pass through the phospholipid bilayers of cell membranes by simple diffusion. Urate transport proteins of cell membranes (URAT1, GLUT9, OAT, MRP4, MCT9, NPT4, ABCG2) are expressed only in uric acid-excreting tissues. These findings suggest that uric acid does not pass through the cell membrane, either by diffusion or active transport. Since uric acid does not pass through cell membranes, the uric acid distribution volume (UDiV) would reflect the extracellular volume (ECV). At ASN 2018, we reported that UDiV significantly correlated with ECV predicted by the bio-impedance method measured by InBody, S 20 (Biospace Co., Ltd, Korea). However, both data were correlated, there was a large fixed error. This time, we examined the correlation with the UDiV again using the Fresenius BCM (Fresenius Medical Care, Bad Homberg, Germany), which is trusted worldwide. Method We calculated UDiV from regular blood test results by uric acid kinetic modeling. This study was performed in Yokohama Minami Clinic. One hundred nine patient under hemodialysis was consented and enrolled in this study. The HD patients were 59males and 50females. 68.0±10.9years old. We performed UDiV calculation from blood samples obtained before and after hemodialysis. Then, after the hemodialysis session, 30minutes interval was made to measure the BIA-ECV using BCM. Then, we compared UDiV with BIA-ECV . We used least squares regression analysis and Bland–Altman analysis to compare the UDiV method and the BIA-ECV method, and the Steel test for multiple comparisons of UDiV and symptoms. All analyses were performed using JMP 9.0.2 (SAS Institute, Inc., Cary, NC, USA). Results There was a significant correlation between UDiV(x) and BIA-ECFV (y): (y = 0.70x +3.02, r-square = 0.61, p &lt; 0.0001, Figure 1a). The regression line closely coincided with the line of identity. Bland–Altman analysis showed a systematic error for UDiVvs. BIA-ECV (Figure 1b). There was a significant difference between UDiVand BIA-ECV (mean difference 1.32 L, 95% CI -2.6 to 5.2 L). Conclusion UdiV could be a viable alternative marker of BIA-ECV for the assessment of hydration status of patients with HD.

scholarly journals Reporting Standards for a Bland–Altman Agreement Analysis: A Review of Methodological Reviews

Diagnostics ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 334 ◽  
Author(s):  
Oke Gerke
Keyword(s):  
A Priori ◽  
Visual Assessment ◽  
Epidemiological Survey ◽  
Altman Analysis ◽  
Limits Of Agreement ◽  
Quality Of Reporting ◽  
Local Study ◽  
Bland Altman Analysis ◽  
Homogeneity Assumption ◽  
Pubmed Search

The Bland–Altman Limits of Agreement is a popular and widespread means of analyzing the agreement of two methods, instruments, or raters in quantitative outcomes. An agreement analysis could be reported as a stand-alone research article but it is more often conducted as a minor quality assurance project in a subgroup of patients, as a part of a larger diagnostic accuracy study, clinical trial, or epidemiological survey. Consequently, such an analysis is often limited to brief descriptions in the main report. Therefore, in several medical fields, it has been recommended to report specific items related to the Bland–Altman analysis. The present study aimed to identify the most comprehensive and appropriate list of items for such an analysis. Seven proposals were identified from a MEDLINE/PubMed search, three of which were derived by reviewing anesthesia journals. Broad consensus was seen for the a priori establishment of acceptability benchmarks, estimation of repeatability of measurements, description of the data structure, visual assessment of the normality and homogeneity assumption, and plotting and numerically reporting both bias and the Bland–Altman Limits of Agreement, including respective 95% confidence intervals. Abu-Arafeh et al. provided the most comprehensive and prudent list, identifying 13 key items for reporting (Br. J. Anaesth. 2016, 117, 569–575). An exemplification with interrater data from a local study accentuated the straightforwardness of transparent reporting of the Bland–Altman analysis. The 13 key items should be applied by researchers, journal editors, and reviewers in the future, to increase the quality of reporting Bland–Altman agreement analyses.

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