Semi-automated Method For Measurement Research Articles

The challenges and uncertainties when hand measuring F1/F2 values in child speech: Towards an automated approach

Vowels serve a critical role in understanding the acoustic properties of speech. Since they appear early in speech development, they can be used to assess important speech milestones. Prior literature provides the empirical foundation for understanding expected F1/F2 values for typically developing children. Although the traditional measurement of the first and second formant frequencies is a widely accepted practice, its clinical use is limited because of the challenges and uncertainties that are encountered during the process. Automated tools have been developed to address these limitations, however many of these tools have been reported to have inconsistencies when identifying F1/F2 values for child speech. This study explores the use of three semi-automated measurement methods: Wavesurfer Linear Predictive Coding, Praat formant tracking, and a lab-developed approach. The speech of six, native English-speaking, four-year-old children with no history of hearing or speech disorders was analyzed. 48 words, including eight American English vowels, were measured using the three approaches by two researchers, an undergraduate researcher, and an experienced research mentor. The challenges, procedural observations, and accuracy of the methods are discussed. This project was supported by the SURIEA summer research internship program.

Automated Data Collection System of Pavement Distresses: Development, Evaluation & Validation of Distress Types and Severities

This study presented an affordable and simpler technique that does not require complex technology and is suitable for middle size road networks. This technique involves taking pictures of various sections of the road network using cameras that can be mounted on public vehicles and transmitting taken images to a processing center. Each image is processed using image filtering techniques to produce an initial estimate of the PI. A total of 5,070 images and 507 sections (4 x 10 m per section) were taken and tested on a part of the Sheikh Maktoum Bin Rashid Highway E11 in Abu-Dhabi city (UAE) based on the quantity and clarity of the distresses. Six types of pavement distresses were tested; (1) longitudinal cracking, (2) alligator cracking, (3) block cracking, (4) pothole distress, (5) transverse cracking and (6) edge cracking. Three severity levels were considered: (1) low, (2) medium and (3) high. There were two distress measurement methods used to identify pavement distresses; semi-automated measurement (SAM) method and automated measurement (AM) method. In order to evaluate the accuracy of the AM method, two expert observers were used individually to extract the pavement distress by using the SAM method. The Cohen’s weighted Kappa used to determine the agreement between the two observers. The overall agreement result of the pavement distresses between the two observers was 98%, which is almost a perfect agreement. The overall agreement result of the pavement distresses between the two measurement methods was 89%, which is again an almost perfect agreement. In addition, the AM method validated by using R2 method and was found to be 0.93. The weighted mean speed of all distresses and standard deviation were found to be 58.56 km/h and 28.24 km/h respectively.

A Semi-Automated Method for Measurement of Left Ventricular Volumes in 3D Echocardiography

Segmentation of the left ventricle in echocardiography data currently poses a challenge, where delineation of the endocardial borders is a time consuming and difficult task. Though semi-automated and fully automated methods have been developed for left ventricular segmentation, they suffer from a number of drawbacks. These drawbacks include the dependence on large sets of training data and assumptions about the distribution of the intensities of the image. This paper proposes a novel volumetric segmentation algorithm based on an angular slicing approach for 3-D echocardiography scans and a diffeomorphic nonrigid registration method. The proposed method is fast, reproducible, and yields a volumetric segmentation with minimal user interaction. The algorithm was evaluated on 30 participants from the challenge on endocardial 3-D ultrasound segmentation dataset from the medical image computing and computer assisted interventions Challenge 2014. The proposed method yielded the following average distance metrics for the end diastolic volumes: 1) mean absolute distance of 2.36 mm, 2) Hausdorff distance of 8.25 mm, and 3) Dice score of 0.887. For the end systolic volumes, the following average distance metrics were obtained: 1) mean absolute distance of 2.33 mm, 2) Hausdorff distance of 8.95 mm, and 3) Dice score of 0.857. The following clinical metrics for the ejection fraction are reported: 1) modified correlation coefficient of 0.169, 2) bias in mL of −3.96 mL, and 3) standard deviation of 6.85 mL. The results demonstrate the robustness of the proposed volumetric segmentation approach.

Accurate quantitative assessment of synovitis in rheumatoid arthritis using pixel-by-pixel, time-intensity curve shape analysis.

To improve on the reproducibility and sensitivity of the assessment of patients with rheumatoid arthritis (RA), two semi-automated measurement methods of the area of enhancing pannus (AEP), based on thresholding (AEP_THRES) and pixel-by-pixel time-intensity curve analysis (AEP_TIC), were evaluated as an alternative for the gold-standard manual contouring method (AEP_MANUAL). 8 patients (7 females and 1 male) with RA of the wrist or finger joints participated in the study. A three-dimensional contrast-enhanced dynamic sequence was used at 3 T. After identifying the most relevant time-intensity curve (TIC) shape in terms of synovitis by comparing with the synovitis score using the RA-MRI scoring system, three different approaches for measuring the AEP were performed. Spearman's test of rank correlation was used to compare AEPs via two semi-automated methods (AEP_THRES and AEP_TIC) against manual segmentation (AEP_MANUAL) in the entire hand region as well as the wrist and the finger regions. The TIC shape of "washout after fast initial enhancement" had excellent correlation with synovitis score (r = 0.809). The correlation coefficient between AEP_TIC and AEP_MANUAL was evaluated to be better than that of AEP_THRES and AEP_MANUAL in the wrist region (AEP_THRES: r = 0.716, AEP_TIC: r = 0.815), whereas these were of comparable accuracy for the entire hand and the finger regions. This study suggests that TIC analysis may be an alternative to manual contouring for pannus quantification and provides important clinical information of the extent of the disease in patients with RA. TIC shape analysis can be applied for new quantitative assessment for RA synovitis in the wrist.

Intra‐operator and inter‐operator reliability of manual and semiautomated measurement of fetal nuchal translucency: a cross sectional study

The goal of this study was to examine the intra-operator and inter-operator differences of the manual and semiautomated nuchal translucency (NT) measurements and to evaluate if these differences alter women's risk status. A cross sectional study was performed. Two operators obtained manual and semiautomated NT measurements of 153 NT images. The maximal acceptable difference in NT measurements within and between operators was 0.15 mm. Intra and inter-operator differences were analyzed by the paired Student's t-test and homogeneity of variances by the Levene's test. Intra-operator and inter-operator agreement were quantified with Bland and Altman's limits of agreement, and changes in women's risk status were tested with the binomial test. Intra-operator agreement was high for each of the measurement methods. Operator 1 had lower SDS for manual measurements. Conversely, operator 2 had lower SDS of the differences for semiautomated measurements, although the SD never reached the same level as operator 1. Inter-operator agreement was highest for the semiautomated measurements. Changes in risk status occurred between the manual and inner-middle method resulting in different clinical policies in up to 1 out of 20 cases. Well-trained operators do not seem to benefit from the use of the semiautomated measurement methods.

3D neuromelanin-sensitive magnetic resonance imaging with semi-automated volume measurement of the substantia nigra pars compacta for diagnosis of Parkinson’s disease

Neuromelanin-sensitive MRI has been reported to be used in the diagnosis of Parkinson's disease (PD), which results from loss of dopamine-producing cells in the substantia nigra pars compacta (SNc). In this study, we aimed to apply a 3D turbo field echo (TFE) sequence for neuromelanin-sensitive MRI and to evaluate the diagnostic performance of semi-automated method for measurement of SNc volume in patients with PD. We examined 18 PD patients and 27 healthy volunteers (control subjects). A 3D TFE technique with off-resonance magnetization transfer pulse was used for neuromelanin-sensitive MRI on a 3T scanner. The SNc volume was semi-automatically measured using a region-growing technique at various thresholds (ranging from 1.66 to 2.48), with the signals measured relative to that for the superior cerebellar peduncle. Receiver operating characteristic (ROC) analysis was performed at all thresholds. Intra-rater reproducibility was evaluated by intraclass correlation coefficient (ICC). The average SNc volume in the PD group was significantly smaller than that in the control group at all the thresholds (P < 0.01, student t test). At higher thresholds (>2.0), the area under the curve of ROC (Az) increased (0.88). In addition, we observed balanced sensitivity and specificity (0.83 and 0.85, respectively). At lower thresholds, sensitivity tended to increase but specificity reduced in comparison with that at higher thresholds. ICC was larger than 0.9 when the threshold was over 1.86. Our method can distinguish the PD group from the control group with high sensitivity and specificity, especially for early stage of PD.

Abstract 251: Semiautomated Measurement of Ascending Aortic Aneurysm Versus Manual Measurement: Assessment of Variability

Purpose: To evaluate inter method and intra observer variability of a novel semi-automated method for measurement of ascending aorta aneurysm (AAA) in ECG gated dual source CT angiogram (DSCTA). Material and Method: Under an IRB approved protocol, multiplanar reformatted images of 40 patients with AAA were measured in DSCTA images. Transaxial maximum diameter of inner wall to inner wall was measured at five anatomic locations of thoracic aorta: annulus, sinus, sinotubular junction (STJ), mid ascending aorta at the level of right pulmonary artery (MAA), and proximal aortic arch immediately proximal to innominate artery (PROX) (Figure 1). Measurements were performed by conventional manual method and the novel semi-automated segmentation software and compared. Inter method and intra observer variability were evaluated according to Intra Class Correlation (ICC). Time required for post processing of the aorta with both methods was recorded in all the cases. Results: Mean maximum diameters in semi-automated method were: annulus 31.10 mm, sinus: 41.95 mm, STJ: 38.05 mm, MAA: 41.88 mm, and PROX: 37.60 mm. Manual method showed mean maximum diameter of 30.87 mm, 42.05 mm, 36.87 mm, 41.18 mm, and 36.42 mm at annulus, sinus, STJ, MAA, and PROX, respectively. There was an excellent inter method and intra observer agreement between two methods at all five points (ICC &gt; 0.9). The post processing time was 8’2’’±1’35” for the semi-automated method while this time was 19’± 20” for the manual method. Conclusion: The novel semi-automated tool demonstrated an excellent agreement with conventional manual method in measurement of AAA in ECG gated DSCTA with the advantage of significant reduction in the post processing time.

Abdominal fat distribution and insulin resistance in Indian women with polycystic ovarian syndrome

The relationship between insulin resistance and abdominal fat distribution was studied in Indian patients with PCOS. Subcutaneous fat, together with a family history of type 2 diabetes mellitus, was the best marker of insulin resistance.

Validity and reliability of active shape models for the estimation of cobb angle in patients with adolescent idiopathic scoliosis.

Choosing the most suitable treatment for scoliosis relies heavily on accurate and reproducible Cobb angle measurement from successive radiographs. The objective is to reduce variability of Cobb angle measurement by reducing user intervention and bias. Custom software to increase automation of the Cobb angle measurement from posteroanterior radiographs was developed using active shape models. Validity and reliability of the automated system against a manual and semiautomated measurement method was conducted by two examiners each performing measurements on three occasions from a test set (N = 22). A training set (N = 47) of radiographs representative of curves seen in a scoliosis clinic was used to train the software to recognize vertebrae from T4 to L4. Images with a maximum Cobb angle between 20 degrees and 50 degrees , excluding surgical cases, were selected for training and test sets. Automated Cobb angles were calculated using best-fit slopes of the detected vertebrae endplates. Intraclass correlation coefficient (ICC) and standard error of measurement (SEM) showed high intraexaminer (ICC > 0.90, SEM 2 degrees -3 degrees ) and interexaminer (ICC > 0.82, SEM 2 degrees -4 degrees ), but poor intermethod reliability (ICC = 0.30, SEM 8 degrees -9 degrees ). The automated method underestimated large curves. The reliability improved (ICC = 0.70, SEM 4 degrees -5 degrees ) with exclusion of the four largest curves (>40 degrees ) in the test set. The automated method was reliable for moderate-sized curves, and did detect vertebrae in larger curves with a modified training set of larger curves.

Variability in Mesothelioma Tumor Response Classification

The objective of our study was to evaluate observer variability in the measurement of temporal change in mesothelioma tumor thickness and in the resulting tumor response classification from CT scans. In addition, the performance of a semiautomated measurement method was evaluated. Four observers individually used an interface that displayed two serial CT scans from the same patient to measure mesothelioma tumor thickness on the follow-up CT scans of 22 patients based on baseline scan measurements. During one session, observers acquired measurements on the follow-up scans based on written reports of baseline scan measurements; in another session, baseline scan measurements were superimposed on the baseline scan for direct visual comparison. Follow-up scan measurements also were obtained from a semiautomated method. Measurement variability and tumor response classification concordance were evaluated for manual measurements acquired in both modes and for semiautomated measurements. Although only a small increase in tumor response classification concordance rate was obtained with the visual approach (84.8%) relative to the more standard written-report approach (82.6%), the actual measurements acquired by observers were statistically significantly different between the two approaches (p = 0.03). Both the semiautomated measurements and the resulting tumor response classifications were consistent with manual measurements. The presentation of baseline scan tumor measurements affects measurements acquired on follow-up scans and could influence tumor response classification. The potential utility of semiautomated tumor thickness measurements was shown in the context of measuring tumor response.

Semi-automated digital image analysis of patellofemoral joint space width from lateral knee radiographs

To design a semi-automated program to measure minimum patellofemoral joint space width (JSW) using standing lateral view radiographs. Lateral patellofemoral knee radiographs were obtained from 35 asymptomatic subjects. The radiographs were analyzed to report both the repeatability of the image analysis program and the reproducibility of JSW measurements within a 2 week period. The results were also compared with manual measurements done by an experienced musculoskeletal radiologist. The image analysis program was shown to have an excellent coefficient of repeatability of 0.18 and 0.23 mm for intra- and inter-observer measurements respectively. The manual method measured a greater minimum JSW than the automated method. Reproducibility between days was comparable to other published results, but was less satisfactory for both manual and semi-automated measurements. The image analysis program had an inter-day coefficient of repeatability of 1.24 mm, which was lower than 1.66 mm for the manual method. A repeatable semi-automated method for measurement of the patellofemoral JSW from radiographs has been developed. The method is more accurate than manual measurements. However, the between-day reproducibility is higher than the intra-day reproducibility. Further investigation of the protocol for obtaining sequential lateral knee radiographs is needed in order to reduce the between-day variability.

Semi-automated digital image analysis of joint space width in knee radiographs

To design a semi-automated program to measure the minimum tibiofemoral joint space width (JSW) of knee radiographs. Bilateral knee radiographs were obtained twice within a 2 week period from 34 asymptomatic research participants. Radiographic images were analyzed to report both the variability of the image analysis program and the reproducibility of JSW measurements within a 2 week period. In addition, the results were compared with minimum JSW measurements read manually by an experienced musculoskeletal radiologist. The variability of the image analysis program was shown to be within one pixel. The results showed that reproducibility was better with the automated method. In addition, the manual method measured a greater minimum JSW than the automated method. There was no significant difference in between-day measurements. There was a significant difference reported between the automated and manual minimum JSW measurements. A novel semi-automated method for measurement of JSW has been developed.

A rapid and reliable semiautomated method for measurement of total abdominal fat volumes using magnetic resonance imaging

The aim of this study was the development of a reliable and fast method to estimate total abdominal fat volumes (TAF) in diabetic subjects on the basis of T1-weighted MR images. Thirty-seven patients with diabetes were examined (age 48 ± 13 y mean ± SD). A semiautomated computer assisted software program was developed to quantify intraabdominal (IAF), subcutaneous (SCF), and total abdominal fat volumes (TAF). The variability of image analysis for fat measurements between two observers and within observers was assessed. Mean volumes (± SD) for IAF, SCF and TAF were 10.5 1 (± 5.0 1), 15.1 1 (±7.3 1) and 25.7 1 (±11.5 1), respectively. Inter- and intraobserver reliability was excellent (r = 0.999 to r = 1.0). Per patient, the analysis required nine minutes in addition to a scan duration of seven minutes. As this analytic method using T1-weighted MR images allows a fast and reliable quantification of TAF, IAF and SCF, it may serve as a valuable tool for respective studies in diabetic subjects.

Brain tumor volume measurement: comparison of manual and semiautomated methods.

To compare the reliability of two approaches to measuring enhancing brain tumor volumes--the conventional manual trace method and a threshold-based, semiautomated computer software method. Two operators rated contrast material-enhanced, T1-weighted axial magnetic resonance (MR) image data sets from 16 patients aged 21-71 years with high-grade gliomas. Each MR data set was rated twice by using manual tracing and twice by using the semiautomated method. The semiautomated measurement method involved a thresholding algorithm based on mixture modeling. The data collection time for each method was recorded. Reliability was measured by using inter- and intraoperator agreement indexes. Mean intraoperator agreement indexes (+/- SD) were 0.90 +/- 0.09 (operator 1) and 0.83 +/- 0.15 (operator 2) for the manual trace method and 0.83 +/- 0.17 (operator 1) and 0.84 +/- 0.16 (operator 2) for the semiautomated measurement method. The mean interoperator agreement was 0.85 +/- 0.14 for the manual method and 0.82 +/- 0.18 for the semiautomated method. The semiautomated method was faster than the manual trace method by an average of 4.6 minutes per patient. The semiautomated computer method of measuring tumor volume was faster than the manual trace method. Semiautomated computer approaches offer an alternative to manual tracing for measuring serial tumor volumes in patients with high-grade brain neoplasms.

Measurement of cell proliferation in microculture using hoechst 33342 for the rapid semiautomated microfluorimetric determination of chromatin DNA

We report the development and characterization of a semiautomated method for measurement of cell proliferation in microculture using Hoechst 33342, a non-toxic specific vital stain for DNA. In this assay, fluorescence resulting from interaction of cell chromatin DNA with Hoechst 33342 dye was measured by an instrument that automatically reads the fluorescence of each well of a 96-well microtiter plate within 1 min. Each cell line examined was shown to require different Hoechst 33342 concentrations and time of incubation with the dye to attain optimum fluorescence in the assay. In all cell lines, cell chromatin-enhanced Hoechst 33342 fluorescence was shown to be a linear function of the number of cells or cell nuclei per well when optimum assay conditions were employed. Because of this linear relation, equivalent cell doubling times were calculated from growth curves based on changes in cell counts or changes in Hoechst/DNA fluorescence and the fluorimetric assay was shown to be useful for the direct assay of the influence of growth factors on cell proliferation. The fluorimetric assay also provided a means for normalizing the incorporation of tritiated thymidine ( [3H] TdR) into DNA; normalized values of DPM per fluorescence unit closely paralleled values of percent 3H-labelled nuclei when DNA synthesis was studied as a function of the concentration of rat serum in the medium. In summary, the chromatin-enhanced Hoechst 33342 fluorimetric assay provides a rapid, simple, and reproducible means for estimating cell proliferation by direct measurement of changes in cell fluorescence or by measurement of changes in the normalized incorporation of thymidine into DNA.