Digital Radiographic Images Research Articles

Comparison of four iterative methods for improving the contrast of the radiography images

Recently, radiography image elaboration using different image processing methods has been introduced as an alternative to enhance the radiographs. The ability of improving the quality of an image depends on the scattered x-ray and the acquisition data by electronic system in digital radiography (DR) (RT). Iterative methods, well known in general sparse signal reconstruction, can be suited for the radiography images. In this research, the DR image is improved by minimizing an objective function using the fast iterative shrinkage-thresholding algorithm (FISTA), Monotone FISTA (MFISTA), over relaxation MFISTA (OMFISTA) and converged FISTA, where the solution sparsity may be adjusted as desired. The paper surveys four well-known methods for sparse process, and assesses their optimization parameters with the goal of obtaining the best algorithm for industrial radiography images. First, the radiographs from the welded objects were provided and four iterative methods were implemented to the radiographs for enhancing the contrast. Then reconstructed images were assessed on the basis of their quality. The results show that the reconstructed images have better contrast than the original radiography and the OMFISTA method has a lower runtime compared to others. Also, the results demonstrate the viability and efficiency of the four proposed algorithms on radiography image deblurring problems without any information about the noise of radiography system.

Can a high-density dental material affect the automatic exposure compensation of digital radiographic images?

To investigate the influence of high-density dental material on the automatic exposure compensation of digital radiographic imaging systems. Two radiographic phantoms were custom made to reproduce radiographic densities of the dental tissues: enamel, dentin and pulp chamber. The phantoms were X-rayed using the Digora Toto, Digora Optime and VistaScan systems for 0.063, 0.1 and 0.16 s. Radiographic acquisitions were repeated in the presence of a high-density material equivalent to a titanium implant, in the small and large sizes. Mean grey values of the dental tissue-equivalent regions were obtained with the Image J software, averaged and compared between the absence and presence of the high-density material using ANOVA for multiple comparisons and Tukey's test (α = 0.05). The presence of a high-density material significantly (p ≤ 0.05) decreased grey values of the dental tissue-equivalent images in the Digora Toto and VistaScan, regardless of the exposure time. For the Digora Optime, the high-density material decreased the pulp-equivalent grey values at all exposure times, the dentin-equivalent grey values significantly increased at exposure time of the 0.1 and 0.16 s, and the enamel-equivalent grey values significantly increased at the exposure time of 0.16 s (p ≤ 0.05). In general, the size of the high-density material did not affect the grey values significantly (p ≤ 0.05). In general, the presence of a high-density dental material in digital radiographic systems influences the AEC by adjusting dental tissue-equivalent grey values.

Method for Automated Selection of the Trabecular Area in Digital Periapical Radiographic Images Using Morphological Operations.

ObjectivesThe aim of this study is to propose a method that automatically select the trabecular bone area in digital periapical radiographic images using a sequence of morphological operations.MethodsThe study involved 50 digital periapical radiographic images of women aged from 36 to 58 years old. The proposed method consists of three stages: teeth detection, trabecular identification, and validation. A series of morphological operations—top-hat and bottom-hat filtering, automatic thresholding, closing, labeling, global thresholding, and image subtraction—are performed to automatically obtain the trabecular bone area in images. For validation, the results of the proposed method were compared with those of two dentists pixel by pixel. Three parameters were used in the validation: trabecular area, percentage of agreed area, and percentage of disagreed area.ResultsThe proposed method obtains the trabecular bone area in a polygon. The obtained trabecular bone area is usually larger than that of previous studies, but is usually smaller than the dentists'. On average over all images, the trabecular area produced by the proposed method is 5.83% smaller than that identified by dentists. Furthermore, the average percentage of agreed area and the average percentage of disagreed area of the proposed method against the dentists' results were 75.22% and 8.75%, respectively.ConclusionsThe shape of the trabecular bone area produced by the proposed method is similar and closer to that identified by dentists. The method, which consists of only simple morphological operations on digital periapical radiographic images, can be considered for selecting the trabecular bone area automatically.

Osteoporosis identification based on the validated trabecular area on digital dental radiographic images

Research for identifying osteoporosis using dental radiographic images is increasing rapidly. Subjects data from various regions and countries have been used by many researchers. This indicates that osteoporosis has become a widespread disease that should be studied more deeply. A method for osteoporosis identification based on the validated trabecular area present on digital dental radiographic images is proposed in this paper. Digital dental radiographic images of subjects were first prepared. This study performs a sequence of morphological operations to obtain the region of interest (RoI) from the validated trabecular area on the images. The validated area is then evaluated using dice similarity method. Bone mineral density is measured using dual X-ray absorptiometry at two sites to assess the presence of osteoporosis. We propose four statistical features, namely deviation, entropy, homogeneity, and correlation, which are extracted from the RoIs. These four features are obtained through feature extraction followed by feature selection using the C4.5 feature selection method. Thereafter, multilayer perceptron is used to predict the presence of osteoporosis by statistical texture analysis. The average dice similarity coefficient for all of RoIs achieves an index of 0.8924. Multilayer perceptron classifier is an appropriate method in our proposed work, which achieves an accuracy of 87.87%. This research shows that the proposed method using the sequence of morphological operations achieves high similarity for forming validated trabecular area and the four statistical features achieves a good performance for osteoporosis identification.

Comparison of the Accuracy of Digital Radiography with Conventional Radiography and Visual Examination in the Detection of Permanent Teeth Interproximal Caries

Objective: To compared the accuracy of digital radiography in the diagnosis of interproximal caries in permanent teeth with conventional radiography and visual examination. Material and Methods: In this descriptive-analytical study, 78 human premolars, which seem normal in primary examination, are mounted on the plaster in a pair-wise manner and their caries are visually evaluated. Conventional and digital radiographic images are taken under the same conditions and their caries are graded with Confidence Score. To determine the golden standard, after mesiodistal incision, the teeth are examined using stereomicroscopy. Finally, the results obtained by visual observation and conventional radiography as well as digital images were compared with those obtained from the stereomicroscopy to determine their accuracy in detecting the interproximal caries. Results: The consistencies between the visual, digital, and conventional methods with the standard method (microscopic histology) are 53%, 78%, and 50% respectively - all of them are significant (p<0.05). The highest and the lowest sensitivities are related to the digital (96%) and visual (88%) methods respectively, while the highest and lowest specificities are related to the digital (79%) and conventional (50%) methods respectively. The highest and lowest positive predictive value is related to the digital (79%) and conventional (80%) methods respectively. The highest and lowest negative predictive values are related to the digital (90%) and visual (71%) methods respectively. Compared with the standard methodology, the most accurate diagnostic accuracy can be seen for the digital method (91%). Conclusion: There is no significant difference in the diagnosis of interproximal caries by different methods, and the only advantage of digital radiography, compared with the conventional one, is storing radiographs without losing important information and the lower dose of radiation for the patient.

Image Quality Assessment of the Digital Radiography Units in Tabriz, Iran: A Phantom Study.

Creating a high-quality image with the low patient dose is one of the most important goals in medical X-ray imaging. In this study, the image quality parameters of the digital radiographic units in Tabriz city were considered and compared with the international protocols. The image quality parameters were measured at 11 high workload digital radiography (DR) imaging centers in Tabriz city, and the results were compared to DINN 6868/58 standards. All centers equipped with the direct DR units passed the spatial resolution, low contrast detectability, contrast dynamic range, and noise tests, while the computed radiography (CR) units only could pass the two last tests. The highest spatial resolution was observed 3.2 lp/mm in the DR unit while the lowest one was 1.8 lp/mm in the CR unit. The highest noise was measured to be 0.03 OD that was observed in the DR unit. The most difference between the nominal and measured peak kilovoltage and mAs was 3.1% and 6.8%, respectively. The entrance surface air kerma in all units was obtained <0.63 mGy. The measured half-value layer range was between 2.4 and 3.54 mmAl. The physical parameters of image quality such as spatial resolution, contrast, and noise are robustness quantitative parameters for the assessment of the image quality performance of the units. Therefore, measurement and control of these parameters using two-dimensional phantoms are very critical.

Adaptation of Single-Cone Gutta-Percha in Curved Canals Prepared and Obturated with Protaper and Heroshaper Systems by Using Cone Beam Computed Tomography.

Objective:The aim of this study is to prepare and obturate the curved canals of the mesiobuccal root of maxillary first molar with four different file systems that is protaper hand files, rotary pro taper (RP) files, heroshaper hand files, and rotary hero shapers files and to evaluate the adaptation of their single-cone Gutta-percha by cone beam computed tomography (CBCT).Materials and Methods:Eighty teeth were selected and were divided into two groups (G1A1, G1A2 and G2A1, G2A2 as hand and RP file system, G1A3, G1A4 and G2A3, G2A4 as hand and rotary hero shaper files system) of fourth teeth each. After access opening working length of the mesiobuccal canal was established. The distobuccal and palatal roots of the samples were removed using the diamond disc at the furcation level. “Endoanalyser” software was used to measure Schneider's angle on the preoperative radiograph. This angle was measured by drawing two lines-one parallel to the long axis of the canal, in the coronal third, and the second line from the apical foramen to intersect the point where the first line left the long axis of the canal. The canals of each group were then prepared according to the manufacturer's instructions for protaper hand files, RP files, heroshaper hand files, and rotary hero shapers files systems. Direct digital radiography image of all the samples was obtained. And then, the samples were exposed to CBCT to evaluate their single-cone adaptations. The data were analyzed using SPSS 20, IBM, Armonk, NY, United States of America.Results:The null hypothesis that there will not be any gap area in the adaptation of their single-cone of different file system was rejected. Minimal gap area was seen in rotary hero shapers file system (0.001 mm2) and was maximum in hand protaper (HP) file system (0.015 mm2).Conclusion:CBCT is a useful tool in detecting the gap area after obturation in curved canals. The HP single-cone adaptation showed the maximum gap area and rotary heroshaper single-cone adaptation showed the minimum gap area.

351. X-ray protective clothings policy

Purpose The main problem associated with the use of X-ray protective clothings is the deterioration and the damages that reduce their efficiency. To overcome this risk, periodic integrity checks are required. At the ASST Lariana a dedicated procedure was developed in order to assess the suitability for use, exploiting acquisition and processing of digital radiographic images. Methods A dedicated database was realized to record all the relevant information and to ensure the control traceability. Two imaging procedures were adopted, depending on the availability of a X-ray fluoroscopic digital system or a CT scanner. Both allowed to acquire the image of the entire device: the first performs a spatial scan by sliding the table while the latter provides a scout image. The recognition and weighing of defects and breaks was carried out both manually, by evaluating the area of a ROI containing the damage, and with a semiautomatic approach by means of an in house software developed in MatLab environment (see Fig.). According to recent INAIL 2016 recommendations, all protective clothings with surface defects >15 mm2 located in the immediate vicinity of a vital organ were rejected. If the defects were not in proximity of a vital organ and had a ⩽670 mm2 surface, the test was considered passed. Results By applying the defect criteria rejection to the examined samples, only 11 out of the 188 controls, corresponding to 5.9% of the tested X-ray protective garments, were rejected. For 20 protective clothes (10.6%) a judgment of partial suitability was issued. All rejected devices have been used for more than seven years. Conclusions The test results allowed to completely define the suitability for use and, eventually, to activate the substitution practices. The adopted control procedure requires technologies that are normally present in hospitals and ensures repeatability, traceability and reliability.

Radiation exposure by digital radiographic imaging in very low birth weight infants.

The aim of this study was to determine the cumulative effective doses (CED) from digital radiographic imaging in very low birth weight infants treated in a tertiary care neonatal intensive care unit (NICU). The CED for each infant was retrospectively calculated using a voxel-based model. The results were compared with previous studies applying conventional radiography. Two hundred and six preterm infants were included into this study. Neonates received a median of four radiographs (range: 1-68) and a CED of 50 µSv (4-883 µSv). Overall mean CED was lower than in previously published data applying conventional radiography. Factors contributing to a lower radiation dose per infant in our study were a lower number of radiographs and smaller field sizes per radiographic image. The number of conducted radiographs per patient and the employed field size had a higher impact on the CED than the applied radiographic technology.

Association between C-reactive protein, neutrophil to lymphocyte ratio and the burden of apical periodontitis: a case-control study

Objective: Endodontic originated chronic apical periodontitis (AP) is an inflammatory disease of periapical tissue. High-sensitivity C-reactive protein (hsCRP) as an inflammatory marker and hemogram indexes provide valuable information to clinicians for diagnosis, screening and follow-up of various diseases. The aim of this study was to investigate AP in terms of its association with hemogram indices and hsCRP levels.Material and methods: Study includes 104 patients with AP and 40 participants as the control group. 160 teeth were diagnosed as AP through digital radiographic images and scored with respect to Periapical Index (PAI) scoring. Afterwards, patients were categorized into 3 grades in accordance with both the number and the severity of AP. AP grade 0 was considered for the control group with regard to a new scoring system. Patients with only one tooth involved with AP with a PAI score of 3 or 4 were categorized as an AP Grade 1, when a patient had more than one tooth with a PAI score of 3 or 4 he was classified as an AP Grade 2 and a patient with at least one tooth scored as a PAI 5 was rated as an AP Grade 3. Hemograms and hsCRP levels were measured for each individual to establish a correlation with inflammatory markers.Results: The neutrophil/lymphocyte ratio (NLR) levels of patients with AP Grade 3 were significantly higher than all other AP grades (p < .05). hsCRP levels in patients with an AP Grade 2 and 3 were higher than both AP Grade 0 and 1 (p < .05).Conclusions: hsCRP levels of patients were reliable predictive indicators for AP severity in correlation with the new proposed scoring system for AP.

High-precision noise power spectrum measurements in digital radiography imaging.

Accurately and precisely estimating the noise power spectrum (NPS) is important for characterizing the performance of a radiography detector and helpful for improving the performance when developing radiography detectors. In order to produce an accurate estimate, the frequency resolution should be sufficiently high, and for a precise estimate, the sample size for the sample mean should also be large enough. However, there is a trade-off between the frequency resolution and the sample size if the available samples are limited. To improve the precision of the estimate, a radial averaging technique is employed in the IEC standard without sacrificing the frequency resolution or the estimate accuracy. In the radial averaging technique, directional NPS curves of a range are averaged from the two-dimensional NPS, and thus, directional error and poor precision problems occur, especially at low frequencies. This problem also leads to uncertainties in calculating the detective quantum efficiency (DQE). Therefore, the purpose of this study is to develop algorithms that can improve the precisions in estimating NPS to replace the radial averaging technique or to add additional precision. The horizontal or vertical NPS curve can be estimated using the sample mean of the summation of directional cross periodograms with various distances from the two-dimensional NPS. In practical x-ray imaging, the amplitude response of the cross periodograms decreases rapidly as the distance increases. Hence, a partial summation of the cross periodograms can provide an accurate estimate of the NPS. This partial summation can increase the sample size and thus improve the estimate precision for the entire frequency range without causing directional errors. This paper proposes two estimate algorithms under the notion of the partial use of cross periodograms. In order to evaluate the precisions from the proposed algorithms, a relative precision, which is defined as the standard deviation of the estimate divided by its average, was employed. The relative precisions were calculated using 100 x-ray images acquired from a general radiography detector. For the detector, we were able to achieve a better precision compared to using the radial averaging technique. For an image of 900×900 pixels and the region of interest size 256 in a direction with a half overlap, the conventional approach of the IEC standard yielded an average relative precision of 6.96% with the worst precision of 36.1% at the zero frequency. However, the proposed algorithms could yield an average relative precision of 4.14% with the zero-frequency precision of 5.79%. Without using the radial averaging technique, the proposed algorithms in this paper could improve the estimate precisions for the entire frequency range under the notion of a partial summation of the cross periodograms. Especially for low frequencies including the zero frequency,the proposed algorithms could achieve a high-precision to estimate the NPS.

Radiographic Axial Malalignment is Associated With Pretreatment Patient-Reported Health-Related Quality of Life Measures in Adult Degenerative Scoliosis: Implementation of a Novel Radiographic Software Tool

Study DesignRetrospective study of prospectively collected data. ObjectivesThe purpose of this study was to evaluate the relationship between apical vertebral axial rotation and pretreatment patient-reported health-related quality of life (HRQOL), disability, and pain in patients with adult degenerative scoliosis (ADS) using a novel radiographic software tool. Summary of Background DataRecent studies have demonstrated that in ADS, sagittal and coronal plane deformity are weakly to moderately associated with HRQOL, disability, and pain. However, as ADS is a three-dimensional spinal deformity, the impact of axial malalignment on HRQOL is yet to be determined. MethodsA total of 74 ADS patients were enrolled. HRQOL measures included the Short Form-36v2 (SF-36v2) and Scoliosis Research Society questionnaire (SRS-22r). Disability and pain measures included the Oswestry Disability Index (ODI) and numeric rating scale back and leg pain. Radiographic measures included Cobb angle (CA), sagittal spinopelvic parameters, lateral and anteroposterior (AP) translation of the apical vertebra. The amount of apical vertebral axial rotation was measured on digital AP radiograph images using a novel software technology. Subjects were stratified into four clinical groups based on the degree of apical vertebral axial rotation. ResultsApical vertebral axial rotation showed no association with lateral (r = 0.21; p = .15) and AP (r = 0.08, p = .80) translation of the apical vertebra. A significant moderate association was found between apical vertebral axial rotation and Cobb angle (r = 0.57; p < .05). Patients in the group with the highest degree of apical vertebral axial rotation reported significantly worse ODI and SRS-22r Subtotal and Pain scores (p < .05), irrespective of sagittal spinopelvic parameters. ConclusionsThis is the first study that reports on the association between apical vertebral axial rotation and pretreatment HRQOL, disability, and pain in ADS. This study suggests that increased apical vertebral axial rotation is associated with suboptimal pretreatment health status scores. Level of EvidenceLevel III.

A modified formulation of eDQE for digital radiographic imaging

The aim of this study was to characterize SNR transfer ability of a digital radiographic system for patient equivalent thicknesses that cover a wide range of clinical examinations Detector MTF, NNPS and DQE measured for different beam qualities using IEC methodology. These measurements were repeated with the grid but aluminum filters of the RQA beam quality were replaced with PMMA slabs of 5, 10, 15, 20 and 25 cm thicknesses. The effects of focus unsharpness were investigated by repeating these measurements with these slabs and positioning the edge phantom at the patient input plane, without the presence of scattering material. eDQE was evaluated for different thicknesses of PMMA slabs using standard and different MTF measurement method. A large region of interest was used to form the edge spread function (ESF), thus including the influence of scattered radiation on the MTF curve; this was termed MTFsys. The system DQE was calculated using MTFsys and abbreviated as modified eDQE (eDQEmod) and compared to the standard method of eDQE. The effect of scatter on the system SNR characteristics is a low spatial frequency effect, while focus unsharpness becomes the main degrading signal transfer factor at higher spatial frequencies. Reasonable agreement was found between modified eDQE (eDQEmod) and eDQE that calculated with standard method for all beam qualities. Inclusion of scattered radiation in the MTF measurement, rather than explicit measurement of scatter fraction (SF) is a quick and reasonably accurate means of estimating the eDQE.

Spinal phantom comparability study of Cobb angle measurement of scoliosis using digital radiographic imaging

SummaryBackgroundComputed radiography (CR), digital radiography (DR) and biplanar radiography (EOS™ imaging system) are common imaging tools for radiographic evaluation of adolescent idiopathic scoliosis (AIS). The effect of imaging methods in relation to later-on Cobb angle measurements on radiographs is not yet quantified. The study aimed to examine the compatibility between CR, DR and EOS for scoliotic quantification by evaluating the reliability, agreement of different imaging methods, and assessing the prediction performance for EOS measurement from that of CR and DR.MethodA flexible spine phantom was used to simulate 32 different scoliotic curves ranging from 10° to 60°. Each curvature was imaged using DR, CR and EOS systems accordingly. Each of the six observers independently measured Cobb angle twice on each image at a two-week interval. Intraclass correlation coefficient (model 2 and 3), Bland-Altman plot and linear regression analysis were completed to evaluate the reliability, agreement, and the prediction of Cobb angle measurement, respectively.ResultsReliability analysis showed excellent intra-observer reliability (Intraclass correlation coefficient >0.9) for each observer and good inter-observer reliability (Intraclass correlation coefficient = 0.84 for EOS; 0.739 for CR; 0.877 for DR) for each method. Bland-Altman plots demonstrated good agreement between imaging methods without fixed or proportional bias. Excellent coefficient of determination was achieved, with 0.980 for CR versus EOS measurements, and 0.973 for DR versus EOS measurements.ConclusionsRadiographs produced by all of the three methods can provide reliable and accurate Cobb angle measurements for scoliosis assessments. None of the methods systemically underestimates or overestimates the Cobb angle measurement. Additionally, all of the evaluated methods are satisfactory in obtaining images for Cobb angle measurement in AIS. However, the 3D post-processing techniques offered by EOS should also be taken into consideration as it takes a vital role in treatment and monitoring of 3D deformity in the case of scoliosis.The translational potential of this articleIn view of the limited availability of biplanar radiography (EOS™ imaging system), computed radiography and digital radiography are demonstrated to be reliable alternatives in scoliosis monitoring as evident in the reliability, agreement and prediction of Cobb angle measurement.

Detection of Proximal Caries at The Molar Teeth Using Edge Enhancement Algorithm

&lt;span&gt;Panoramic X-Ray produces produces the most common oral digital radiographic image that it used in dentistry practice. The image can further improve accuracy compared to analog one. This study aims to establish proximal caries edge on enhancement images so they can be easily recognized. The images were obtained from the Department of Radiology, General Hospital of M. Djamil Padang Indonesia. Total file of images to be tested were 101. Firstly, the images are analyzed by dentists who practiced at Segment Padang Hospital Indonesia. They concluded that there is proximal caries in 30 molar teeth. Furthermore, the images were processed using Matlab software with the following steps, i.e. cropping, enhancement, edge detection, and edge enhancement. The accuracy rate of detection of edge enhancement images being compared with that of dentist analysis was 73.3%. In the edge enhancement images proximal caries edge can be found conclusively in 22 teeth and dubiously in eight teeth. The results of this study convinced that edge enhancement images can be recommended to assist dentists in detecting proximal caries. &lt;/span&gt;

Effect of patellar luxation on radiographic measurements of tibial plateau angle in small-breed dogs.

OBJECTIVE To determine whether medial patellar luxation would affect radiographic tibial plateau angle (TPA) measurements in small-breed dogs. DESIGN Prospective cross-sectional study. ANIMALS 15 small-breed dogs (25 stifle joints) with grade 2 or 3 medial patellar luxation (5 dogs with unilateral luxation and 10 dogs with bilateral luxation). PROCEDURES Digital mediolateral radiographic images of each affected stifle joint were acquired with the patella in manually reduced (n = 25) and luxated (25) positions. In 2 measurement sessions separated by > 48 hours, 3 observers unaware of patella status (luxated or reduced) measured the TPA in each image twice in random order. Mixed linear modeling was performed to determine the effect of patella status on TPA measurements, and intraobserver and interobserver variation in measurements were calculated. RESULTS TPA measurements by all observers differed significantly between the first and second measurement sessions, but by a mean value of only 0.7°. A few significant differences were identified between 1 pair of observers by patella status and between patella statuses for 1 observer, but all mean differences were ≤ 1.7°. No significant difference in intraobserver variation was identified between patella statuses for any observer. Interobserver variation was not affected by patella status and measurement session. CONCLUSIONS AND CLINICAL RELEVANCE Although some significant differences were identified in radiographic TPA measurements in dogs with medial patellar luxation, depending on whether the patella was luxated or manually reduced, these differences were so small they could be considered clinically unimportant. Consequently, we believe that in small-breed dogs with patellar luxation, patella status would be unlikely to have a clinically meaningful effect on the measured TPA.

Emergency radiology after a massive earthquake: clinical perspective.

Earthquakes are unpredictable and inevitable disasters, causing various earthquake-related disorders. Medical imaging, including digital radiography, computed tomography, and magnetic resonance imaging, plays a key role in the evaluation of earthquake-related disorders. We here demonstrate the concept of diagnostic imaging after a massive earthquake and review the common imaging features of various disorders in casualties and evacuees. This summary of imaging features can facilitate the diagnosis of various earthquake-related disorders and promote judicious therapy planning.

Digital radiography image denoising using a generative adversarial network.

Statistical noise may degrade the x-ray image quality of digital radiography (DR) system. This corruption can be alleviated by extending exposure time of detectors and increasing the intensity of radiation. However, in some instances, such as the security check and medical imaging examination, the system demands rapid and low-dose detection. In this study, we propose and test a generative adversarial network (GAN) based x-ray image denoising method. Images used in this study were acquired from a digital radiography (DR) imaging system. Promising results have been obtained in our experiments with x-ray images for the security check application. The Experiment results demonstrated that the proposed new image denoising method was able to effectively remove the statistical noise from x-ray images, while kept sharp edge and clear structure. Thus, comparing with the traditional convolutional neural network (CNN) based method, the proposed new method generates more plausible-looking images, which contains more details.

OA211] A single phantom, a single statistical method, a single figure of merit for all X-ray equipment

Purpose The aim of this study is to collect Statistical Low Contrast Detectability Threshold (LCth) data from different equipment using the same phantom and the same software for the analysis. All data will be expressed with same unit, that is mmAl. Equipment types include: Digital radiography (DR), Computed Radiography (CR), 2D Digital Mammography, Tomosynthesis and Syntetic 2D Mammography, Fluoroscopy, Fluorography and Digital Subtracted Angiography (DSA) from Angiography. Data from this study will define the reference value and the tolerance for quality control tests. Methods and materials A phantom consisting of a square aluminium target and a 5-step-wedge (0.25–1.25 mmAl) was built. A Matlab software automatically calculates LCth values in terms of Pixel Value (PV) and it also converts PV to mmAl, providing the LCth(mmAl). Standard setting used for different modality: RQA5 beam at 2.5 μGy kerma entrance at the detector for DR and CR; automatic acquisition with 16 cm of PMMA filtration for angiography and 5 cm PMMA phantom for mammography setting. The images analysed in this study are both processed and unprocessed. Results This method is able to collect low contrast detectability information from different modalities and equipment by different vendors. Preliminary results are summarized by detail. For example, for 0.5 mm diameter detail results in the range of: 0.05–0.08, 0.04–0.093, 0.018–0.023, 0.26–0.3 and 0.36–0.41 mmAl LCth for tomosynthesis images, synthetic 2D, 2D mammography, DR and CR images, respectively. Furthermore, from the intercomparison activity of AIFM working group on angiographic equipment, for 2.5 mm diameter detail, results have been derived in the range of: 0.35–0.88, 0.31–0.58, 0.35–0.49, 0.046–0.59 LCth expressed in mmAl unit for low dose and normal dose fluoroscopy, coronary fluorography, cerebral DSA, respectively. Conclusion The Low Contrast Detectability phantom and statistical method can be easily implemented for all modalities. Data from this study can be used to define the reference value and the tolerance for low contrast threshold quality control in digital radiography.

The value of digital tomosynthesis for Schatzker classification in tibial plateau fractures

Objective To investigate the diagnostic value of digital tomosynthesis in Schatzker classification of tibial plateau fractures. Methods A total of 43 patients with tibial plateau fractures who had underwent injured knee joints coronal tomosynthesis examinations and as well as digital radiography (DR) examinations including anteroposterior and lateral positions before the surgery were selected from January to June 2015. The imaging evaluation was performed by two diagnostic radiologists independently. Each radiologist consecutively performed Schatzker classification of the DR and tomosynthesis images of the knees of each patient. The consistent Schatzker classification results were finally given, while the inconsistent classification results were discussed. Recording the reading results of two methods and comparing the classification results of two methods with the subsequent intra-operative classification results, evaluating their consistency. Results Twenty-eight patients were included with 14 males and 14 females. The age ranged from 25 to 76 years old with an average of 48.5 years. Fifteen patients were excluded due to combined injuries and the low quality of imaging. Schatzker classification of tibial plateau fractures was performed with DR images, 19 cases of fracture classification results were consistent with intra-operative classification, and 9 cases were inconsistent. Twenty-six cases of fracture classification results were consistent with intra-operative classification based on tomosynthesis images but 2 cases with inconsistent results. Intra-operative findings for each fracture were used as the gold standard for classification. The accuracy of the Schatzker classification for tibial plateau fractures were 68% and 93% in the two imaging techniques with significant difference (χ2=5.143, P=0.016), respectively. The classification results of two imaging methods in 2 patients were both inconsistent with intra-operative classification. The fracture severity of 6 patients was underestimated when using DR images for interpretation, while 1 patient had a missed diagnosis of the lateral tibial plateau collapsed fracture. The consistency between the classification results of DR images as well as classification results of tomosynthesis images and intra-operative typing were moderately and highly consistent, respectively (Kappa coefficient were 0.604 and 0.908, respectively). Conclusion Schatzker classification of tibial plateau fractures was performed with DR images, the lateral tibial plateau collapsed fracture and the lateral plateau splitting fracture could be easily missed or misdiagnosed. However, tomosynthesis imaging could provide a higher accuracy. Key words: Tibial fractures; Radiography; Diagnosis