Deep learning approach to femoral AVN detection in digital radiography: differentiating patients and pre-collapse stages.

OBJECTIVE: This study aimed to evaluate a new deep-learning model for diagnosing avascular necrosis of the femoral head (AVNFH) by analyzing pelvic anteroposterior digital radiography. METHODS: The study sample included 1167 hips. The radiographs were independently classified into 6 stages by a radiologist using their simultaneous MRIs. After that, the radiographs were given to train and test the deep learning models of the project including SVM and ANFIS layer using the Python programming language and TensorFlow library. In the last step, the test set of hip radiographs was provided to two independent radiologists with different work experiences to compare their diagnosis performance to the deep learning models' performance using the F1 score and Mcnemar test analysis. RESULTS: The performance of SVM for AVNFH detection (AUC = 82.88%) was slightly higher than less experienced radiologists (79.68%) and slightly lower than experienced radiologists (88.4%) without reaching significance (p-value > 0.05). Evaluation of the performance of SVM for pre-collapse AVNFH detection with an AUC of 73.58% showed significantly higher performance than less experienced radiologists (AUC = 60.70%, p-value < 0.001). On the other hand, no significant difference is noted between experienced radiologists and SVM for pre-collapse detection. ANFIS algorithm for AVNFH detection with an AUC of 86.60% showed significantly higher performance than less experienced radiologists (AUC = 79.68%, p-value = 0.04). Although reaching less performance compared to experienced radiologists statistically not significant (AUC = 88.40%, p-value = 0.20). CONCLUSIONS: Our study has shed light on the remarkable capabilities of SVM and ANFIS as diagnostic tools for AVNFH detection in radiography. Their ability to achieve high accuracy with remarkable efficiency makes them promising candidates for early detection and intervention, ultimately contributing to improved patient outcomes.

Patient dose and associated exposure parameters in pelvic x-ray examinations: dependence on radiographic system.

Technological differences between computed radiography (CR) and digital radiography (DR) systems can influence patient doses and exposure parameters in pelvic x-ray examinations. The presence of radiosensitive organs in the pelvic region underscores the need to optimize these parameters for both CR and DR systems. This prospective study aimed to compare the patient doses and exposure parameters for adult patients undergoing pelvic x-ray examinations using CR and DR systems, based on data from Sri Lanka. The study included data from 56 x-ray examinations, with 25 using CR and 31 using DR. Patient demographic characteristics and exposure parameters (kVp: kilovoltage peak, mAs: tube current-exposure time product) were recorded, and patient doses were measured in terms of the kerma-area product (PKA) using a PKA meter. Despite similar mean weight and body mass index (BMI), the CR systems showed significantly higher mean kVp (7.4%), mAs (16.4%), and PKA (29.7%) than the DR systems (CR - kVp: 73.2, mAs: 37.8, PKA: 2.29 Gy cm2; DR - kVp: 67.8, mAs: 31.6, PKA: 1.61 Gy cm2). The Mann-Whitney U test revealed statistically significant differences in PKA and kVp between the CR and DR systems (p < 0.05). Furthermore, even with lower patient weight and BMI, the mean mAs and PKA in this study were substantially higher than those reported in the literature for both CR and DR systems. These results suggest the need to optimize current mAs settings for the studied hospitals and introduce radiographic system-specific exposure parameters and reference dose levels for pelvic x-ray examinations in order to enhance patient protection.

Distances and angles in standing long-leg radiographs: comparing conventional radiography, digital radiography, and EOS.

OBJECTIVE: Distances and angles measured from long-leg radiographs (LLR) are important for surgical decision-making. However, projectional radiography suffers from distortion, potentially generating differences between measurement and true anatomical dimension. These phenomena are not uniform between conventional radiography (CR) digital radiography (DR) and fan-beam technology (EOS). We aimed to identify differences between these modalities in an experimental setup. MATERIALS AND METHODS: A hemiskeleton was stabilized using an external fixator in neutral, valgus and varus knee alignment. Ten images were acquired for each alignment and each modality: one CR setup, two different DR systems, and an EOS. A total of 1680 measurements were acquired and analyzed. RESULTS: We observed great differences for dimensions and angles between the 4 modalities. Femoral head diameter measurements varied in the range of > 5 mm depending on the modality, with EOS being the closest to the true anatomical dimension. With functional leg length, a difference of 8.7% was observed between CR and EOS and with the EOS system being precise in the vertical dimension on physical-technical grounds, this demonstrates significant projectional magnification with CR-LLR. The horizontal distance between the medial malleoli varied by 20 mm between CR and DR, equating to 21% of the mean. CONCLUSIONS: Projectional distortion resulting in variations approaching 21% of the mean indicate, that our confidence on measurements from standing LLR may not be justified. It appears likely that among the tested equipment, EOS-generated images are closest to the true anatomical situation most of the time.

Bedside diagnosis of silent aspiration using mobile dynamic digital radiography: a preliminary study.

PURPOSE: This study aimed to assess reliable options for bedside diagnosis of silent aspiration in the intensive care unit by examining the use of default grayscale images (DGI) obtained using a mobile, general-purpose, radiography system capable of dynamic digital radiography (M-DDR) and inverted grayscale images (IGI) of DGI. METHODS: This cohort study (exploratory and preliminary) involved 18 adult patients (mean age, 89.0 years) for whom a swallowing assessment request was received from their primary physicians. Fifty-six IGI videoclips were evaluated by three specialists using the penetration-aspiration scale (PAS), with the gold standard being the consensus reading of all three specialists. Another three speech-language pathologists (SLPs) assessed 56 DGI and IGI videoclips using the PAS. PAS scores 1 and 2 were classified as normal range, PAS scores 3-5 as pathological laryngeal penetration, and PAS scores 6-8 as aspiration. The correct rates with IGI and DGI were then determined, and the level of agreement of IGI and DGI evaluations was evaluated. RESULTS: The correct rate of all evaluators was 100% for normal range, 80-100% for pathological laryngeal penetration, and 83-100% for aspiration with IGI and 100% for normal range, 90% for pathological laryngeal penetration, and 83% for aspiration with DGI. The kappa coefficient for IGI and DGI showed almost complete agreement for abnormal conditions. CONCLUSION: Dynamic imaging of swallowing 2-5 ml of liquid using M-DDR performed for elderly patients at the bedside showed that aspiration assessments by SLPs obtained from DGI videos immediately after imaging are acceptable.

Automatic image quality evaluation in digital radiography using for-processing and for-presentation images.

PURPOSE: To investigate the impact of digital image post-processing algorithms on various image quality (IQ) metrics of radiographic images under different exposure conditions. METHODS: A custom-made phantom constructed according to the instructions given in the IAEA Human Health Series No.39 publication was used, along with the respective software that automatically calculates various IQ metrics. Images with various exposure parameters were acquired with a digital radiography unit, which for each acquisition produces two images: one for-processing (raw) and one for-presentation (clinical). Various examination protocols were used, which incorporate diverse post-processing algorithms. The IQ metrics' values (IQ-scores) obtained were analyzed to investigate the effects of increasing incident air kerma (IAK) on the image receptor, tube potential (kVp), additional filtration, and examination protocol on image quality, and the differences between image type (raw or clinical). RESULTS: The IQ-scores were consistent for repeated identical exposures for both raw and clinical images. The effect that changes in exposure parameters and examination protocol had on IQ-scores were different depending on the IQ metric and image type. The expected positive effect that increasing IAK and decreasing tube potential should have on IQ was clearly exhibited in two IQ metrics only, the signal difference-to-noise-ratio (SDNR) and the detectability index (d'), for both image types. No effect of additional filtration on any of the IQ metrics was detected on images of either type. An interesting finding of the study was that for all different image acquisition selections the d' scores were larger in raw images, whereas the other IQ metrics were larger in clinical images for most of the cases. CONCLUSIONS: Since IQ-scores of raw and their respective clinical images may be largely different, the same type of image should be consistently used for monitoring IQ constancy and when results from different X-ray systems are compared.

Development of a correction coefficient for radiographic evaluation of the alveolar bone crest: a pilot study.

OBJECTIVES: To analyze the differences in cusp height on radiographs, establishing proportional relationships between cusp and alveolar bone crest (ABC) measurements. The goal of this study was to develop a correction coefficient by considering this proportion. MATERIALS AND METHODS: Twenty-one artificial teeth, molars and premolars, and bovine ribs were used. Interproximal radiographs were taken with the aid of a positioner. The vertical angles used were: 0°, + 5°, and + 10°, and processed using three spatial resolutions measured in line pairs per mm (lp/mm): 20, 25 and 40. The Perio filter was applied to each image, in addition to the original one. Combinations of angle, resolution, and filter were made. Eighteen images were analyzed by three specialists, resulting in 252 measurements for each evaluator, totaling 756 measurements. RESULTS: The overall variability of the measurements can be explained mainly by the variation in tooth anatomy. The 0° 25 lp/mm Perio filter method was the closest one to the actual clinical scenario for both cusps and ABC. The correction factor managed to explain 71.45% of the errors. CONCLUSIONS: The variation in vertical angulation interferes with cusp and ABC measurements, and the angulation at 0º and spatial resolution of 25 lp/mm showed better results. The use of correction coefficients allowed approaching actual measurement values. CLINICAL RELEVANCE: More accurate ABC height measurements are essential even in radiographic exams that do not meet the standard of excellence because the need to repeat radiographic exams is then eliminated.

Impact of enhancement filters of a CMOS system on halo artifact expression at the bone-to-implant interface.

OBJECTIVE: To assess the impact of enhancement filters on the formation of halo artifacts in radiographs of dental implants obtained with a complementary metal oxide semiconductor (CMOS) system. METHODS: Digital radiographs of dental implants placed in dry human mandibles were processed with the Noise Reduction smoothing filter, as well as the Sharpen 1, Sharpen 4, and Sharpen UM high-pass filters available in the CLINIVIEW™ software (Instrumentarium Dental, Tuusula, Finland). Subjective analysis involved evaluating the left, right, and apical surfaces of each implant for the presence of much, few, or no halo. The objective analysis involved measurement of the halo area using the Trainable Weka Segmentation plugin (ImageJ, National Institutes of Health, Bethesda, MD, USA). Data were analyzed using Friedman's test (subjective analysis) and ANOVA (objective analysis) (α = 5%). RESULTS: In the subjective evaluation, the Sharpen 4 filter produced more radiographs with much halo present, and in the objective evaluation, a bigger halo area when compared to the original images and the Noise Reduction filter for all surfaces (p < 0.05). CONCLUSIONS: When evaluating dental implants, priority should be given to original images and those enhanced with smoothing filters since they exhibit fewer halo artifacts. CLINICAL RELEVANCE: Post-processing tools, such as enhancement filters, may improve the image quality and assist some diagnostic tasks. However, little is known regarding the impact of enhancement filters in halo formation on CMOS systems, which have been increasingly used in dental offices.

Residual networks models detection of atrial septal defect from chest radiographs.

OBJECT: The purpose of this study was to explore a machine learning-based residual networks (ResNets) model to detect atrial septal defect (ASD) on chest radiographs. METHODS: This retrospective study included chest radiographs consecutively collected at our hospital from June 2017 to May 2022. Qualified chest radiographs were obtained from patients who had finished echocardiography. These chest radiographs were labeled as positive or negative for ASD based on the echocardiographic reports and were divided into training, validation, and test dataset. Six ResNets models were employed to examine and compare by using the training dataset and was tuned using the validation dataset. The area under the curve, recall, precision and F1-score were taken as the evaluation metrics for classification result in the test dataset. Visualizing regions of interest for the ResNets models using heat maps. RESULTS: This study included a total of 2105 chest radiographs of children with ASD (mean age 4.14 ± 2.73 years, 54% male), patients were randomly assigned to training, validation, and test dataset with an 8:1:1 ratio. Healthy children's images were supplemented to three datasets in a 1:1 ratio with ASD patients. Following the training, ResNet-10t and ResNet-18D have a better estimation performance, with precision, recall, accuracy, F1-score, and the area under the curve being (0.92, 0.93), (0.91, 0.91), (0.90, 0.90), (0.91, 0.91) and (0.97, 0.96), respectively. Compared to ResNet-18D, ResNet-10t was more focused on the distribution of the heat map of the interest region for most chest radiographs from ASD patients. CONCLUSION: The ResNets model is feasible for identifying ASD through children's chest radiographs. ResNet-10t stands out as the preferable estimation model, providing exceptional performance and clear interpretability.

The radiographic evaluation of 11 different resin composites.

Radiopacities of dental materials used in restorations are very important in making the radiographic diagnosis. Therefore, the aim of our study was to evaluate the radiopacity of five single-shade and six simplishade resin composites with digital technique. Five different single-shade (Charisma Topaz One, Omnichroma, Clearfil Majesty ES-2 Universal, Vittra APS Unique, ZenChroma) and six different simplishade resin composites (G-aenial A'CHORD, Essentia Universal, OptiShade, Estelite Asteria, Filtek Universal, Filtek Z250) were used. For each group, five disk-shaped resin composites of 1 mm and 2 mm thicknesses were prepared. As a control, tooth slices with 1 mm and 2 mm thicknesses and a 99.5% pure aluminum step-wedge were used. The samples, tooth slices, and a step-wedge were placed on a photostimulable phosphor plate. Digital radiographs were taken from 30 and 40 cm distances (70 kVp, 7 mA 0.28 ms). The images were analyzed using ImageJ software to measure the mean gray values. Data were analyzed using SPSS 22 package program and Kruskal-Wallis H Test (p < 0.05). The highest radiopacity was seen in Filtek Universal at both distances and thicknesses. Omnichroma had the lowest radiopacity in all parameters. All specimens showed higher radiopacity than dentin. Except for Omnichroma 1 and 2 mm thick, Clearfil Majesty ES-2 Universal 2 mm thick, samples showed higher radiopacities than enamel (p < 0.05). The restorative materials tested were found to be more radiopaque than dentin. The samples passed the International Organization for Standardization for radiopacity values. The radiopacity values were affected by thickness and type of materials.

Peracetic Acid Efficacy on Disinfection of Photostimulable Phosphor Plates.

OBJECTIVES: To evaluate the antimicrobial efficacy of white vinegar, acetic acid and peracetic acid on photostimulable phosphor (PSP) plates disinfection, and to assess the disinfectant influence on the radiographic quality. METHODS: Eight PSP plates (Express system) were contaminated with Streptococcus mutans and Candida albicans. These plates were wiped with tissues without any substance, with white vinegar, acetic acid, and peracetic acid, followed by an agar imprint. Number of microbial colonies formed was recorded. Afterwards, the quality of radiographs was tested using the more efficient disinfectant. Before disinfection and after every five disinfections, two radiographs of an acrylic-block and two radiographs of an aluminum step-wedge were acquired for each plate. Density, noise, uniformity, and contrast were analyzed. Three oral radiologists evaluated the images for the presence of artifacts. One-way Analysis of Variance compared changes on gray values among the disinfections (α = 0.05). Intra- and inter-examiner agreement for the presence of artifacts was calculated by weighted Kappa. RESULTS: Peracetic acid was the only one that eliminated both microorganisms. Density and uniformity decreased after 100 disinfections, and contrast changed without a pattern in the course of disinfections (P ≤ 0.05). Small artifacts were observed after 30 disinfections. Intra- and inter-examiner agreements were almost perfect. CONCLUSIONS: Disinfection with peracetic acid eliminated both microorganisms. However, it also affected density, uniformity and contrast of radiographs, and led to the formation of small artifacts.

Evaluation of the performance of digital x-ray systems in pelvis radiography.

The aim of this study was to investigate the performance of eight digital radiography systems and to optimise the dose-image quality relationship for digital pelvis radiography. The study involved eight digital radiography systems used for general examinations at Vilnius University Hospital Santaros Klinikos. An anthropomorphic pelvic phantom (CIRS, US) was used to simulate a patient undergoing clinical pelvis radiography. Dose quantities entrance surface dose, dose area product (DAP) and exposure parameters (kVp, mA, mAs) were measured and the effects on the images were evaluated, considering physical contrast to noise ratio (CNR) and observer-based evaluations as image quality metrics. Increasing the tube voltage by 5 kVp from standard protocol led to a reduction in radiation dose (DAP) by 12%-20% with a slight impact on image quality (CNR decreases by 2%-10%). There was an inter-observer variability in image rating across different equipment (kappa value between 0 and 0.3); however, both observers agreed that increasing kVp up to 85-90 kV had no effect on perceived image quality. The results indicate that optimisation strategies should be tailored specifically for each x-ray system since significant performance differences and wide variations in radiation dose exist across various digital radiography systems used in clinical settings. The use of high kVp can be used for dose optimisation in digital pelvis radiography without compromising image diagnostic accuracy.

Comparative evaluation and patient satisfaction with an electrical impedance-based device versus digital radiography in the estimation of remaining dentin thickness in carious posterior permanent teeth: (Diagnostic accuracy study).

BACKGROUND: Accurate assessment of remaining dentin thickness (RDT) is paramount for restorative decisions and treatment planning of vital teeth to avoid any pulpal injury. This diagnostic accuracy study compared the validity and patient satisfaction of an electrical impedance based device Prepometer™ (Hager & Werken, Duisburg, Germany) versus intraoral digital radiography for the estimation of remaining dentin thickness in carious posterior permanent teeth. METHODS: Seventy patients aged 12-25 years with carious occlusal or proximal permanent vital posterior teeth were recruited. Tooth preparation was performed to receive an adhesive restoration. Pre- and post-excavation RDT were measured radiographically by two calibrated raters using the paralleling periapical technique. Prepometer™ measurements were performed by the operator. Patients rated their satisfaction level with each tool on a 4-point Likert scale and 100 mm visual analog scale (VAS). Inter and intragroup comparisons were analyzed using signed rank test, while agreement between devices and observations was tested using weight kappa (WK) coefficient. RESULTS: the intergroup comparisons showed that, before and after excavation, there was a significant difference between measurements made by both techniques (p < 0.001). After excavation, there was a weak agreement between measurements (WK = 0.2, p < 0.001), whereas before excavation, the agreement was not statistically significant (p = 0.407). Patients were significantly more satisfied with Prepometer™ based on scales and VAS (p < 0.001). CONCLUSION: Prepometer™ could be a viable clinical tool for determining RDT with high patient satisfaction, while radiographs tended to overestimate RDT in relation to the Prepometer™.

Enhanced visualization of mobile chest X-ray images in the intensive care setting using software scatter correction.

BACKGROUND: Mobile chest X-ray (CXR) scans are performed within intensive treatment units (ITU) without anti-scatter grids for confirming tube and line hardware placement. Assessment is therefore challenging due to degraded subject contrast resulting from scatter. PURPOSE: To evaluate the efficacy of a software scatter correction method (commercially named Trueview) for enhanced hardware visualization and diagnostic quality in the ITU setting. MATERIAL AND METHODS: A total of 30 CXR scans were processed using Trueview and compared with standard original equipment manufacturer (OEM) images via observer scoring study involving two radiology and four ITU doctors to compare visualization of tubes and lines. Results were analyzed to determine observer preference and likelihood of diagnostic quality. RESULTS: Reviewers were more likely to score Trueview higher than OEM for mediastinal structures, bones, retrocardiac region, tube visibility, and tube safety (P < 0.01). Visual grading characteristic analysis suggested a clinical preference for Trueview compared with OEM for mediastinal structures (area under the visual grading characteristic curve [AUCVGC] = 0.60, 95% confidence interval [CI] = 0.55-0.65), bones (AUCVGC = 0.61, 95% CI = 0.55-0.66), retrocardiac region (AUCVGC = 0.64, 95% CI = 0.59-0.69), tube visibility (AUCVGC = 0.65, 95% CI = 0.60-0.70), and tube safety (AUCVGC = 0.68, 95% CI = 0.64-0.73). Reviewers were indifferent to visualization of the lung fields (AUCVGC = 0.49, 95% CI = 0.44-0.55). Registrars (3/6 reviewers) were indifferent to the mediastinal structure regions (AUCVGC = 0.54, 95% CI = 0.47-0.62). CONCLUSION: Reviewers were more confident in identifying the placement and safety of tubes and lines when reviewing Trueview images than they were when reviewing OEM.

Workload and use factor data for a modern digital radiography system.

The well-referenced structural shielding design NCRP Report No. 147 uses workload information based on self-reported film-screen data from the AAPM Task Group 9 survey. The aim of this study was to assess the clinical workload distributions of modern digital radiography (DR) systems in general hospital and pediatric-only practices. A retrospective analysis of DR imaging data on four radiographic systems in a hospital practice and two radiographic systems in a pediatric practice, through a custom clinical DICOM header analytics program. A total of 203, 294 exposures from the general hospital practice and 25,415 from the pediatric practice from 2019 and 2021 were included. Values for kVp, mAs, and detector type (wall bucky, table bucky, or free detector) were extracted. For each exam, mAs was accumulated in a kVp histogram with bins 5 kVp wide and further parsed by detector type. Total workload was calculated by summing all exposures, then normalized by the number of patients. The median (25th and 75th percentile) workload in the hospital practice was 0.43 (0.22, 1.13) mA-min per patient, while the average was 1.36 ± 3.08. Pediatric data yielded a median (25th and 75th percentile) of 0.10 (0.05, 0.23) and an average of 0.29 ± 0.69 mA-min per patient. Mean number of patients per week was 230 adult and 57 pediatric. Hospital workload data is approximately 44% less than the NCRP Report No. 147 value.

Preoperative assessment of pleural adhesions in patients with lung cancer based on quantitative motion analysis with dynamic chest radiography: A retrospective study.

PURPOSE: Preoperative assessment of pleural adhesion is crucial for appropriate surgical planning. This study aimed to quantitatively evaluate the usefulness of motion analysis using dynamic chest radiography (DCR) for assessing pleural adhesions. METHODS: Sequential chest radiographs of 146 lung cancer patients with or without pleural adhesions (n = 25/121) were obtained using a DCR system during respiration (registration number: 1729). The local motion vector was measured, and the percentage of poor motion area to the maximum expiration lung area (%lung area with poor motion) was calculated. Subsequently, percentage values ≥49.0% were considered to indicate pleural adhesions. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated to assess the prediction performance. The percentage of lung area with poor motion was compared between patients with and without pleural adhesions (p < 0.05). RESULTS: DCR-based motion analysis correctly predicted pleural adhesions in 21 out of 25 patients, with 47 false-positive results (sensitivity, 84.0%; specificity, 61.2%; PPV, 30.9%; NPV, 94.9%). The lung with pleural adhesions showed a significantly greater %lung area with poor motion than the opposite lung in the same patient, similar to the cancerous lung in patients without pleural adhesions. CONCLUSION: On DCR-based motion analysis, pleural adhesions could be indicated by an increase in the percentage of lung area with poor motion. Although the proposed method cannot identify the exact location of pleural adhesions, information regarding the presence or absence of pleural adhesions provided by DCR would help surgeons prepare for challenging surgeries and obtain informed consent from patients.

Radiation dose considerations in digital radiography with an anti-scatter grid: A study using adult and pediatric phantoms.

BACKGROUND: When using an anti-scatter grid, a decrease in receptor dose caused by its X-ray absorption seems to lead to the misperception that radiation dose needs to be increased even in digital radiography (DR). OBJECTIVE: To demonstrate that there is no need to increase radiation dose in DR with a grid, based on a visual evaluation using an adult and a pediatric abdomen phantom (PAD and PPD , respectively). MATERIALS AND METHODS: Phantom images with and without a grid were obtained with exposure parameters determined based on a preliminarily measured signal-to-noise ratio improvement factor (SIF), an index for potential dose reduction when using a grid. In visual evaluation, four radiologists compared phantom images with a grid applied at different dose reduction rates (0% [no reduction], 18%, 36%, and 59% for PAD and 0% and 11% for PPD ) against an image without a grid at the baseline dose (as the reference). They graded the overall image quality of the former relative to that of the latter (reference) on a 3-point scale (3 = better, 2 = almost equal, 1 = worse). RESULTS: The mean scores for dose reduction rates of 0%, 18%, 36%, and 59% were 3.00, 3.00, 2.75, and 1.00, respectively, for PAD ; those for 0% and 11% were 2.13 and 1.63, respectively, for PPD . These results support the validity of our view that no dose increase is necessary when using an anti-scatter grid. Actually, there is even a potential for improvement in image quality with dose reduction rates of ≤36% for PAD . CONCLUSION: It is worth reconsidering the necessity of increasing radiation dose in the DR imaging of the adult and pediatric abdomens with an anti-scatter grid.

AAPM task group report 305: Guidance for standardization of vendor-neutral reject analysis in radiography.

Reject rate analysis is considered an integral part of a diagnostic radiography quality control (QC) program. A rejected image is a patient radiograph that was not presented to a radiologist for diagnosis and that contributes unnecessary radiation dose to the patient. Reject rates that are either too high or too low may suggest systemic department shortcomings in QC mechanisms. Due to the lack of standardization, reject data often cannot be easily compared between radiography systems from different vendors. The purpose of this report is to provide guidance to help standardize data elements that are required for comprehensive reject analysis and to propose data reporting and workflows to enable an effective and comprehensive reject rate monitoring program. Essential data elements, a proposed schema for classifying reject reasons, and workflow implementation options are recommended in this task group report.

Bi-planar calibration method for templating of hip joint arthroplasty: phantom study and proof of concept.

PURPOSE: Calibration of radiographs is a critical step in digital templating for hip arthroplasty. Calibration errors of > 1.5% lead to over- or undersizing of the templated implants and may affect logistics and patient safety. Contemporary calibration methods are known to be imprecise with average errors of 6.5% and wide variance. A novel bi-planar radiograph-based calibration method is proposed, and a phantom study was conducted as proof of concept. METHODS: A spherical external calibration marker (ECM) is placed in front of the pubic symphysis of a pelvic bone model at twelve different positions. For each marker position, standard anteroposterior radiographs and four corresponding lateral radiographs with different degrees of rotation (0°-30°) are taken (overall, 60 radiographs). Calibration factors are calculated for an internal calibration marker (ICM) at the centre of the right hip (reference) and the ECM using a novel algorithm. Rotation and marker positions simulate foreseeable use errors and misplacements and aim to test robustness of the method against these errors. RESULTS: ECM calibration factor was 125.9% (range 124.7-127.2), and the mean ICM calibration factor was 126.6% (range 126.2-127.1) ([Formula: see text]). Four images (8.3%) were beyond the 1% error threshold (all with 30° rotation). The mean difference was 0.79% (SD 0.49). CONCLUSION: The bi-planar method precisely predicts the true calibration factor of the hip joint plane under various conditions. In lateral radiographs, rotation of up to 20° did not adversely affect the precision and all images had calibration errors below the threshold for clinical significance.

Dual-scale single marker calibration for digital templating of total hip arthroplasty in standing radiographs: a prospective clinical study.

PURPOSE: Accuracy of calibration of radiographs significantly influences the quality of digital templating for total hip arthroplasty (THA). The standard of care is calibration with external calibration markers (ECM). This method is associated with significant errors. Dual-scale single marker (DSSM) calibration methods may improve accuracy. The present prospective observational study is the first to analyze the application of a DSSM method in standing pelvis radiographs. METHODS: 100 patients with unilateral THA underwent antero-posterior pelvis radiographs with ECM and DSSM. The hip components were used as reference calibration factor (internal calibration factor; ICM). Absolute differences of calibration factors for ECM and DSSM from ICM were calculated. Absolute relative deviations (ARD) were calculated. Subgroup analysis for sex and WHO BMI category was performed. Furthermore, patients reported subjective comfort for each marker using a 10-point scale and choosing the preferred marker. RESULTS: Maximum magnification factor differences from the ICM were 23.3% and 9.5% and mean absolute differences were 12.5% and 2.1% for the ECM and DSSM, respectively. ARD from ICM was significantly lower for DSSM compared to ECM (p < 0.001). Absolute differences increased with BMI category using ECM; calibration by DSSM was consistent in all subgroups. Patients preferred DSSM over ECM (n = 53) or were indifferent (n = 20). Comfort was rated significantly higher for DSSM versus ECM (p < 0.001). CONCLUSION: DSSM method showed superior results in comparison to the ECM method for calibration of digital radiographs. DSSM could be used to improve digital templating in standing radiographs.

Evaluation of diagnostic accuracy of CBCT and intraoral radiography for proximal caries detection in the presence of different dental restoration materials.

PURPOSE: This study aimed to assess the diagnostic accuracy of cone-beam computed tomography (CBCT) and digital intraoral radiography for the detection of proximal caries adjacent to amalgam, e.max porcelain, and metal-ceramic restorations (MCRs). MATERIALS AND METHODS: Parallel intraoral radiographs were obtained from 40 posterior teeth using PSP sensors. To obtain CBCT scans, the teeth were first radiographed alone, and were then positioned next to a tooth with an amalgam restoration, MCR, and e.max porcelain crown, and radiographed again. Two blinded observers scored radiographs using a four-point scale (0: absence of proximal caries, 1: enamel caries, 2: carious lesion extending to the outer half of dentin, 3: carious lesion extending to the inner half of dentin). Tooth sections were made, and the grade of caries was determined under a light microscope at x12 magnification. The sensitivity, specificity, and accuracy of CBCT and intraoral radiographs were then calculated. RESULTS: Artifact-free CBCT scans and intraoral radiographs had the highest diagnostic accuracy (0.826 and 0.657, respectively) while CBCT images of the teeth next to the amalgam restorations (0.526) had the lowest accuracy. The diagnostic accuracy of CBCT images of the teeth next to the porcelain crowns and MCRs was 0.613 and 0.601, respectively. CONCLUSION: Artifact-free CBCT images had higher diagnostic accuracy than intraoral radiography for the detection of all grades of proximal caries. The diagnostic accuracy of CBCT images of teeth adjacent to amalgam, porcelain, and MCRs was lower compared to intraoral radiographs and artifact-free CBCT images.