Intraobserver Reproducibility Of Measurements Research Articles

Volume and T2 relaxation time measurements of quadriceps femoris and hamstring muscles are reliable and reproducible

Background/aimVolume and T2 relaxation time measurements of the skeletal muscle provide quantitative information. We aimed to evaluate the interobserver reliability and the intraobserver reproducibility of measurements of volumes and T2 relaxation times of the quadriceps femoris and the hamstring muscles.Materials and methodsA cross-sectional reliability study was conducted on ten recreational athletes. The images of the quadriceps and the hamstring muscles of both limbs were obtained using a 3.0 Tesla magnetic resonance imaging (MRI) scanner. Two sports medicine specialists measured muscle volumes from a total of 2560 images and T2 relaxation times from a total of 40 images, and repeated this once more. The intraobserver and interobserver compliance were assessed by the intraclass correlation coefficient (ICC) and Cronbach’s alpha (α).ResultsVolume and T2 relaxation time of quadriceps femoris and hamstring muscle measurements with MRI had good to excellent reliability (Muscle volume; intraobserver ICCs: between 0.97 and 0.99, α: between 0.98 and 0.99 and interobserver ICCs: between 0.96 and 0.99, α: 0.99. T2 relaxation time; intraobserver ICCs: between 0.74 and 0.96, α: between 0.85 and 0.98 and interobserver ICCs: between 0.75 and 0.90, α: between 0.85 and 0.95).ConclusionVolume and T2 relaxation time measurements of the quadriceps femoris and the hamstring muscles are reliable and reproducible.

Characterization of Perineum Elasticity and Pubic Bone-Perineal Critical Distance with a Novel Tactile Probe: Results of an Intraobserver Reproducibility Study.

Background:Tactile imaging provides biomechanical mapping of soft tissues. Objective biomechanical and anatomical assessment of critical structures within the vagina and pelvis may allow development and validation of a clinical tool that could assist with clinical decisions regarding obstetrical procedures and mode of delivery. Objective: To assess intraobserver reproducibility of measurements of perineal elasticity and pubic bone-perineal critical distance with a novel tactile probe in pregnant women.Methods:An Antepartum Tactile Imager (ATI) was designed with a vaginal probe resembling a fetal skull. The probe comprises 128 tactile sensors on a double curved surface and measures 46 mm in width and 72 mm in length. The probe has a motion tracking sensor that allows acquisition of 3D tactile images. There were two arms of the study. In the first arm, biomechanical mapping of the perineum and pelvic bone location was performed in 10 non-pregnant women for purposes of demonstrating safety and feasibility. In the second arm, biomechanical mapping was performed in 10 pregnant women to explore intraobserver reproducibility. Each subject had two standardized examinations over 3 – 5 minutes by the same observer. Examination comfort and pain levels were assessed by post-procedure survey. Reproducibility was analyzed by intraclass correlation coefficients (ICC) with 95% confidence intervals and Bland-Altman plots. Bias and the 95% limits of agreement were also calculated.Results:The safety and feasibility arm of the study demonstrated high degree of safety and tolerability and reliable acquisition of tactile signals. In the reproducibility arm, 10 pregnant women were recruited at mean gestational age of 34.2 ± 6.5 weeks. The mean perineum elasticity (Young’s modulus, E) was 9.8 ± 5.9 kPa, and the mean pubic bone-perineal critical distance (D) at 20 kPa load was 34.6 ± 6.2 mm. The ICC was 0.97 [95% confidence interval (CI) 0.91, 0.99] and 0.82 [CI 0.44, 0.95] for E and D respectively, consistent with excellent intrarater agreement. The bias and the 95% limits of agreement of E were −6.3% and −29.4% to +16.7%, respectively. The bias and the 95% limits of agreement of D were −2.6% and −25.3% to +20.2%, respectively.Conclusions:The tactile imaging data obtained in the study reproducibly characterized perineal elasticity and pubic bone-perineal critical distance. Further evaluation of this tool in clinical settings is warranted.

Evaluation of age by Kvaal’s modified measurements (KMM) using computer-aided imaging software and digitized parameters

IntroductionIn the field of forensic science, identification of the unknown is the primary task to be done by forensic experts. Age assessment is one of the most important biological parameters of identification. The durability of teeth makes them one of the most suitable evidence for age estimation. AimThe present study was performed to develop and validate new teeth specific multiple regression models for age estimation based on Kvaal’s modified measurements (KMM) and to check whether this approach leads to statistically comparable and reproducible results or not. Material and MethodSample comprised of 1280 RVGs of 4 teeth per subject (maxillary canine, maxillary second premolar, mandibular canine, and mandibular first premolar) collected from 320 individuals (160 males and 160 females) having the age range 15–54 years. Thirteen radiographic measurements (3 vertical and 10 horizontal) were performed on all radiographs using computer-aided software (Adobe Photoshop). Various ratios from these vertical as well as horizontal measurements were calculated. These ratios were subjected to multiple regressions. Developed multiple regression models were validated for their accuracy on a different set of 80 RVGs obtained from another 20 subjects of known age. Comparative analysis was done to check the difference between the mean chronological age and estimated age. ResultsIt was found that the pulpal width showed a better correlation with the chronological age when contrasted with vertical ratios. The concordance correlation coefficient was used to check the intraobserver reproducibility of measurements. The multiple regression models were established. The determination coefficients (r2) of the models for all the studied tooth varies from 0.331 to 0.631 with SEE varies from 6.27 to 7.89 years. Results of the present study suggested a significant negative correlation between chronological age and variables. Maxillary second premolar demonstrated the most noteworthy value of r2. ConclusionThe results of the present study give an inference for the feasibility of this technique. Our study indicates that the width measurements are age-dependent variable in adults as these ratios showed a better correlation with age. High resolution of RVGs has improved the age estimation error rate.

4D flow MRI quantification of mitral and tricuspid regurgitation: Reproducibility and consistency relative to conventional MRI

In patients with mitral or tricuspid valve regurgitation, evaluation of regurgitant severity is essential for determining the need for surgery. While transthoracic echocardiography is widely accessible, it has limited reproducibility for grading inlet valve regurgitation. Multiplanar cardiac MRI is the quantitative standard but requires specialized local expertise, and is thus not widely available. Volumetric 4D flow MRI has potential for quantitatively grading the severity of inlet valve regurgitation in adult patients. To evaluate the accuracy and reproducibility of volumetric 4D flow MRI for quantification of inlet valvular regurgitation compared to conventional multiplanar MRI, which may simplify and improve accessibility of cardiac MRI. This retrospective, HIPAA-compliant imaging-based comparison study was conducted at a single institution. Twenty-one patients who underwent concurrent multiplanar and 4D flow cardiac MRI between April 2015 and January 2017. 3T; steady-state free-precession (SSFP), 2D phase contrast (2D-PC), and postcontrast 4D flow. We evaluated the intertechnique (4D flow vs. 2D-PC), intermethod (direct vs. indirect measurement), interobserver and intraobserver reproducibility of measurements of regurgitant flow volume (RFV), fraction (RF), and volume (RVol). Statistical analysis included Pearson correlation, Bland-Altman statistics, and intraclass correlation coefficients. There was high concordance between 4D flow and multiplanar MRI, whether using direct or indirect methods of quantifying regurgitation (r = 0.813-0.985). Direct interrogation of the regurgitant jet with 4D flow showed high intraobserver consistency (r = 0.976-0.999) and interobserver consistency (r = 0.861-0.992), and correlated well with traditional indirect measurements obtained as the difference between stroke volume and forward outlet valve flow. 4D flow MRI provides highly reproducible measurements of mitral and tricuspid regurgitant volume, and may be used in place of conventional multiplanar MRI. 4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:1147-1158.

Intraobserver reproducibility of retinal nerve fiber layer measurements using scanning laser polarimetry and optical coherencetomography in normal and ocular hypertensive subjects.

To evaluate quantitatively the intraobserver reproducibility of measurements of the retinal nerve fiber layer (RNFL) in healthy subjects and an ocular hypertensive population using two nerve fiber analyzers. Sixty eyes of normal (n=30) and ocular hypertensive subjects (n=30) were consecutively recruited for this study and underwent a complete ophthalmologic examination and achromatic automated perimetry. RNFL were measured using scanning laser polarimeter (GDx-VCC) and optical coherence tomography (OCT Model 3000). Reproducibility of the RNFL measurements obtained with both nerve fiber analyzers were compared using the coefficient of variation. In both groups the authors found fair correlations between the two methods in all ratio and thickness parameters. The mean coefficient of variation for measurement of the variables ranged from 2.24% to 13.12% for GDx-VCC, and from 5.01% to 9.24% for OCT Model 3000. The authors could not detect any significant differences between healthy and ocular hypertensive eyes, although in normal eyes the correlations improved slightly. Nev-ertheless, the testretest correlation was slightly better for GDx-VCC than for OCT Model 3000 (5.55% and 7.11%, respectively). Retinal mapping software of both nerve fiber analyzers allows reproducible measurement of RNFL in both healthy subjects and ocular hypertensive eyes, and shows fair correlations and good intraobserver reproducibility. However, in our study, GDx showed a better testretest correlation. (Eur J Ophthalmol 2004; 14: 523-30).

Three-dimensional maxillary and mandibular regional superimposition using cone beam computed tomography: a validation study

This study aimed to validate a novel method for fast regional superimposition of cone beam computed tomography (CBCT) scans. The method can be used with smaller field of view scans, thereby allowing for a lower radiation dose. This retrospective study used two dry skulls and secondary data from 15 patients who had more than one scan taken using the same machine. Two observers tested two types of regional voxel-based superimposition: maxillary and mandibular. The registration took 10–15s. Three-dimensional surface models of the maxillas and mandibles were generated via standardized threshold segmentation, and the accuracy and reproducibility of the superimpositions were assessed using the iterative closest point technique to measure the root mean square (RMS) distance between the images. Five areas were measured and a RMS≤0.25 was considered successful. Descriptive statistics and the intra-class correlation coefficient (ICC) were used to compare the intra-observer measurement reproducibility. The ICC was ≥0.980 for all of the variables and the highest RMS found was 0.241. The inter-observer reproducibility was assessed case by case and was perfect (RMS 0) for 68% (23 out of 34) of the superimpositions done and not clinically significant (RMS≤0.25) for the other 32%. The method is fast, accurate, and reproducible and is an alternative to cranial base superimposition.

Reproducibility of Regional and Global Longitudinal Strains Derived from Two-Dimensional Speckle-Tracking and Doppler Tissue Imaging between Expert and Novice Readers during Quantitative Dobutamine Stress Echocardiography

Longitudinal strain (LS) is a quantitative parameter that adds incremental value to wall motion analysis. The aim of this study was to compare the reproducibility of LS derived from Doppler tissue imaging and speckle-tracking between an expert and a novice strain reader during dobutamine stress echocardiography (DSE). Forty-one patients (mean age, 65 ± 15 years; mean ejection fraction, 58 ± 11%) underwent DSE per clinical protocol. Global LS derived from speckle-tracking and regional LS derived from both speckle-tracking and Doppler tissue imaging were measured twice by an expert strain reader and also measured twice by a novice strain reader. Intraobserver and interobserver analyses were performed using intraclass correlation coefficients (ICC), Bland-Altman analysis, and absolute difference values (mean ± SD). Global LS measured by the expert strain reader demonstrated high intraobserver measurement reproducibility (rest: ICC = 0.95, absolute difference = 5.5 ± 4.9%; low dose: ICC = 0.96, absolute difference = 5.7 ± 3.7%; peak dose: ICC = 0.87, absolute difference = 11.4 ± 8.4%). Global LS measured by the novice strain reader also demonstrated high intraobserver reproducibility (rest: ICC = 0.97, absolute difference = 4.1 ± 3.4%; low dose: ICC = 0.94, absolute difference = 5.4 ± 5.9%; peak dose: ICC = 0.94, absolute difference = 6.1 ± 4.8%). Global LS also showed high interobserver agreement between the expert and novice readers at all stages of DSE (rest: ICC = 0.90, absolute difference = 8.5 ± 7.5%; low dose: ICC = 0.90, absolute difference = 8.9 ± 7.1%; peak dose: ICC = 0.87, absolute difference = 10.8 ± 8.4%). Of all parameters studied, LS derived from Doppler tissue imaging had relatively low interobserver and intraobserver agreement. Global LS is highly reproducible during all stages of DSE. This variable is a potentially reliable and reproducible measure of myocardial deformation.

Measurement of Scleral Thickness using Swept-Source Optical Coherence Tomography in Patients With Open-Angle Glaucoma and Myopia

To use swept-source optical coherence tomography (OCT) to image the posterior sclera at the posterior pole and around the optic nerve head (ONH) and measure the subfoveal scleral thickness and laminar thickness to evaluate the relationship between the measured thicknesses and ocular parameters. Prospective, cross-sectional design. The study included 103 patients with glaucoma and 43 controls with axial lengths more than 26 mm. Swept-source OCT images were obtained to capture the subfoveal and ONH regions. Subfoveal scleral thickness and laminar thickness were measured from obtained B-scan images. To verify the reproducibility of the measurement, intraclass correlation coefficients were calculated from selected B-scans. Scleral and laminar thicknesses in patients with normal-tension glaucoma (NTG) was compared with that in patients with primary open-angle glaucoma (POAG). A Pearson correlation was calculated to assess the relationships of scleral and laminar thicknesses with ocular parameters. Posterior scleral thickness could be measured in 68.4% of patients, and laminar thickness could be measured in 88.6% by using swept-source OCT. Interobserver and intraobserver measurement reproducibility was moderate to excellent. The subfoveal scleral thickness was 670.84 ± 160.60 μm in the POAG group and 496.55 ± 115.20 μm in the NTG group; a significant difference between the groups was observed. Subfoveal scleral thickness (r = -0.677, P < 0.001) was negatively correlated with axial length only in patients with NTG, not in patients with POAG. Swept-source OCT detected differences in the thicknesses of the posterior sclera between eyes with NTG and eyes with POAG. Subfoveal scleral thickness was negatively correlated with axial length only in eyes with NTG.

Wall-to-lumen ratio of retinal arterioles

Wall-to-lumen ratio of retinal arterioles

Reproducibility of Cornea Measurements in Anterior Segment OCT Images of Normal Eyes and Eyes with Bullous Keratopathy Analyzed with the Zhongshan Assessment Program

To determine the interobserver and intraobserver measurement reproducibility of cornea parameters of both normal eyes and eyes with bullous keratopathy (BK) obtained with the Zhongshan Assessment Program (ZAP) on anterior segment optical coherence tomography (AS-OCT) images. A comparative study was carried out on 24 healthy volunteers and 25 subjects with BK. AS-OCT images were independently analyzed by two examiners. Parameters examined: anterior chamber depth (ACD), central corneal thickness (CCT), posterior corneal curvature (PCC), and posterior corneal arc length (PCAL). Interobserver and intraobserver reproducibility of these parameters was calculated in terms of limits of agreement (mean of differences ± 1.96SD of differences). In the normal group, both horizontal and vertical ACD were successfully measured in 23 of 24 (96%) images. The mean bias for two measurements by two different observers ranged from 0.003 to 0.117 mm for ACD, PCC, and PCAL measurements and from 0.013 to 2.25 μm for CCT measurements, and there were no differences between the two observers (P > 0.05). Mean bias for two measurements by the same grader ranged from 0.005 to 0.327 mm for ACD, PCC, and PCAL measurements and 1.46 to 2.53 μm for CCT measurements. There was no difference between the two observations (P > 0.05). Similar results were found in the BK group. There was high inter- and intraobserver reproducibility for normal and pathologic corneas using the ZAP software. The ZAP software may serve as a new investigatory tool for accurately evaluating the anterior segment and corneal parameters for corneal procedures.

Manufacturing and placing a bespoke support for the Marfan aortic root: description of the method and technical results and status at one year for the first ten patients

Fatal aortic dissection commonly occurs in Marfan syndrome. Prevention currently relies on elective replacement of the aortic root. We are evaluating the placement of a manufactured, bespoke external support derived from a computer aided design in a prospective study. In the first ten patients, measurements were made consistently of the ascending aorta at the level of closure of the aortic valve cusps from magnetic resonance imaging (MRI) studies taken preoperatively and at fixed intervals thereafter. Before and after images were presented for measurement amongst duplicate images of 37 unoperated Marfan patients to permit assessment of intra-observer measurement reproducibility. All images were presented in random sequence to a radiologist unaware of the research question. The largest difference between the preoperative measurement and that made at least one year after surgery was determined. All patients had surgery as planned without complications and were alive at one year. In eight of the ten patients, the largest observed change was a marked reduction in aortic root diameter. The primary objective of this surgery was achieved in each case, reinforcing the ascending aorta whilst leaving the native aortic valve intact and conserving the blood/endothelium interface.

Comparison of Different Modes in Optical Coherence Tomography and Ultrasound Biomicroscopy in Anterior Chamber Angle Assessment

To compare anterior chamber angle width measurements by low and high-resolution anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM). Thirty-six eyes of 32 patients with gonioscopically narrow angles from a university-based glaucoma clinic were recruited in the study. All subjects received AS-OCT {in "Anterior Segment Single" mode [low-resolution optical coherence tomography (LOCT)] and "High-resolution Cornea" mode [high-resolution optical coherence tomography (HOCT)]} and UBM examination in 1 or both eyes. Angle opening distance (AOD) and angle recess area of temporal (t) and nasal (n) quadrants were assessed using the customized software on each type of image. Angle measurements from UBM, LOCT, and HOCT images were compared; intraobserver and interobserver measurement reproducibility for each type of image was also evaluated. Thirty-three eyes of 29 patients were available for analysis. No significant differences were found between LOCT and UBM in the measurement of t-AOD (P=0.350), n-AOD (P=0.106), and n-angle recess area (P=0.360). HOCT measurements were significantly larger than both LOCT and UBM for all parameters (all, P<0.05). HOCT images had better interobserver and intraobserver measurement reproducibility than UBM images. LOCT is similar to UBM for most of the studied angle measurements. HOCT tends to give larger measurements than both LOCT and UBM. AS-OCT measurements were more reproducible than those from UBM.

Intraobserver Reproducibility of Retinal Nerve Fiber Layer Measurements Using Scanning Laser Polarimetry and Optical Coherence Tomography in Normal and Ocular Hypertensive Subjects

Purpose To evaluate quantitatively the intraobserver reproducibility of measurements of the retinal nerve fiber layer (RNFL) in healthy subjects and an ocular hypertensive population using two nerve fiber analyzers. Methods Sixty eyes of normal (n=30) and ocular hypertensive subjects (n=30) were consecutively recruited for this study and underwent a complete ophthalmologic examination and achromatic automated perimetry. RNFL were measured using scanning laser polarimeter (GDx-VCC) and optical coherence tomography (OCT Model 3000). Reproducibility of the RNFL measurements obtained with both nerve fiber analyzers were compared using the coefficient of variation. Results In both groups the authors found fair correlations between the two methods in all ratio and thickness parameters. The mean coefficient of variation for measurement of the variables ranged from 2.24% to 13.12% for GDx-VCC, and from 5.01% to 9.24% for OCT Model 3000. The authors could not detect any significant differences between healthy and ocular hypertensive eyes, although in normal eyes the correlations improved slightly. Nevertheless, the test–retest correlation was slightly better for GDx-VCC than for OCT Model 3000 (5.55% and 7.11%, respectively). Conclusions Retinal mapping software of both nerve fiber analyzers allows reproducible measurement of RNFL in both healthy subjects and ocular hypertensive eyes, and shows fair correlations and good intraobserver reproducibility. However, in our study, GDx showed a better test–retest correlation.

Reproducibility of pulsed Doppler measurements of the maternal renal circulation in normal pregnancies and those with pregnancy-induced hypertension.

To assess the inter- and intraobserver reproducibilities of pulsed Doppler measurements of the maternal renal circulation in normal pregnancies and those affected by pregnancy-induced hypertension. Color and pulsed Doppler ultrasound was used to measure acceleration time and resistance index in the renal segmental and interlobar arteries. For the investigation of interobserver reproducibility, two sonographers performed measurements blindly in six normal pregnant women and 14 women with pregnancy-induced hypertension between 28 and 36 weeks' gestation. A second group of 10 patients between 30 and 35 weeks' gestation were examined by one sonographer to assess the level of intraobserver reproducibility of measurements. For each patient in this group, the flow waveform was measured three times in succession. Calculations of the intraclass correlation coefficient Ri were used to determine the level of reproducibility. The interobserver Ri and intraobserver Ri for acceleration time in the segmental artery were 0.95 and 0.96 and for the interlobar artery they were 0.97 and 0.98, respectively. For the resistance index, these values were 0.01 and 0.01 in the segmental artery and 0.52 and 0.29 in the interlobar artery. Both the inter- and intraobserver reproducibility of acceleration time measurements in the renal segmental and interlobar arteries were clinically acceptable but the equivalent reproducibilities of resistance index measurements were poor.

Passive terminal extension causes anterior tibial translation in some anterior cruciate ligament-deficient knees

The purpose of the present study was to accurately measure anterior tibial translation during passive terminal extension (ATT-PTE) in anterior cruciate ligament (ACL)-deficient knees, and to investigate correlations between various characteristics of such knees and the magnitude of ATT-PTE. The subjects were 79 patients with unilateral ACL-deficient knees and little flexion contracture. All patients were confirmed to have ACL injury of one knee by arthroscopy. Lateral radiographs of the bilateral knees in passive terminal extension were compared, and ATT-PTE was measured using an original superimposition method. The inter-observer and intra-observer reproducibility of measurement was significantly greater for this method than for the method without superimposition. In 42 of the 79 patients (53%), ATT-PTE was greater than 1mm, while it was greater than 4mm in 15 patients (19%). ATT-PTE was significantly larger in patients with a large anterior displacement difference (as measured with the KT-1000 arthrometer) (ATT-KT), a long period since injury, a history of reinjury, injury to the meniscus, and the presence of gross pivot shift. On the other hand, ATT-KT was equal to or greater than 2.5mm in all 79 patients and showed no significant correlation with the time since initial injury, history of reinjury, on injury to the meniscus.

Validation of a dual energy X-ray absorptiometer: measurement of bone mass and soft tissue composition

We investigated the reproducibility of total and regional body composition measurements performed on a dual energy X-ray absorptiometer (DXA). A group of 58 women aged 21-81 (mean 52.4) years was scanned twice with repositioning to determine intraobserver reproducibility of measurements of bone mineral density (BMD, g.cm-2), bone mineral content (BMC, g), lean mass (LM, kg) and fat mass (FM, kg) of the total body and of the major subregions of the body. In addition, the ability of the DXA machine to detect changes in LM and FM (simulated by placing 11.1 and 22.3 kg porcine lard on the body of 11 subjects) was examined. Coefficients of variations calculated from the root mean square averages of individual standard deviations were as follows (BMD, BMC, LM, FM) [corrected]: 1.4%, 1.1%, 1.4%, 1.7% (total body), 2.2%, 2.1%,-,- (head), 2.8%, 2.8%, 2.0%, 2.2% (trunk), 3.6%, 3.9%, 4.0%, 4.9% (arms), 2.7%, 1.3%, 2.6%, 2.8% (legs). Percentage fat (%fat) of exogenous lard was 81.3 (SD 3.5)% as assessed by the absorptiometer which corresponded well with the result of chemical analysis (82.8%). Estimated %fat of exogenous lard was not influenced by initial body mass or percentage body fat. Percentages of expected mean values with 11.1 kg lard placed on the body were 99.9 (SD 0.3) for body mass, 100.5 (SD 2.1) for LM, and 99.5 (SD 3.5) for FM. BMD was overestimated by 3.2% (P < 0.005) with 11.1 kg lard on the body. BMD as well as BMC increased significantly with 22.3 kg lard on the body (P < 0.005). The results showed that BMD, BMC, LM, and FM of the total body were precisely estimated by the DXA machine used. Regional measurements were less precise. Changes in total body soft tissue composition were precisely and accurately estimated. The lard placed on the body falsely affected BMD and BMC measurements. Changes in body mass could have a similar effect.