A Multitarget Interested Region Extraction Method for Wrist X-Ray Images Based on Optimized AlexNet and Two-Class Combined Model

This paper introduces some latest developments regarding the X-ray imaging methodology and applications of the X-ray imaging and biomedical application beamline (BL13W1) at Shanghai Synchrotron Radiation Facility in the past 5 years. The photon energy range of the beamline is 8–72.5 keV. Several sets of X-ray imaging detectors with different pixel sizes (0.19–24 μm) are used to realize X-ray microcomputed tomography (X-ray micro-CT) and X-ray in-line phase-contrast imaging. To satisfy the requirements of user experiments, new X-ray imaging methods and image processing techniques are developed. In vivo dynamic micro-CT experiments with living insects are performed in 0.5 s (sampling rate of 2 Hz, 2 tomograms/s) with a monochromatic beam from a wiggler source and in 40 ms (sampling rate of 25 Hz, 25 tomograms/s) with a white beam from a bending magnet source. A new X-ray imaging method known as move contrast X-ray imaging is proposed, with which blood flow and moving tissues in raw images can be distinguished according to their moving frequencies in the time domain. Furthermore, X-ray speckle-tracking imaging with twice exposures to eliminate the edge enhancement effect is developed. A high-precision quantification method is realized to measure complex three-dimensional blood vessels obtained via X-ray micro-CT. X-ray imaging methods such as three-dimensional X-ray diffraction microscopy, small-angle X-ray scattering CT, and X-ray fluorescence CT are developed, in which the X-ray micro-CT imaging method is combined with other contrast mechanisms such as diffraction, scattering, and fluorescence contrasts respectively. Moreover, an X-ray nano-CT experiment is performed with a 100 nm spatial resolution. Typical user experimental results from the fields of material science, biomedicine, paleontology, physics, chemistry, and environmental science obtained on the beamline are provided.

Region of interest (ROI) extraction and crack detection for UAV-based bridge inspection using point cloud segmentation and 3D-to-2D projection

Refraction contrast X-ray imaging experiments were conducted on acrylic resin with an artificial cylindrical hole, A7075 aluminum alloy, A6063 aluminum castings, mild steel with cracks or voids, and low alloy steel with inclusions, using a ultra-bright synchrotron radiation X-ray beam in BL24XU hutch C of SPring-8. Conventional absorption contrast X-ray imaging experiments were also done for the comparison. The X-ray beam was controlled to be monochromatic by Si double-crystals and collimated by a slit. The distance between the sample and the detector was changed from 0 to 3 m, and the X-ray energy was 15 to 25 keV. Photographs were taken by X-ray film and/or X-ray CCD camera. As a result, the refraction imaging method gave a much more distinct image of the artificial cylindrical hole in acrylic resin as compared with the absorption method. The fatigue cracks in aluminum alloy and mild steel were also distinctly observed. The X-ray imaging revealed the presence of MnS nonmetallic inclusions in low alloy steel. Void defects in aluminum castings were clearly detected by the imaging. In addition, in-situ observation of tensile fracture of aluminum alloys using a high resolution X-ray CCD camera system was successfully conducted. The observations by use of asymmetric reflection technique for X-ray imaging experiment were also well performed. From above, the X-ray imaging method using ultra-bright synchrotron radiation is concluded to be very useful for fracture research of materials.

Finger Vein Recognition System (FVRS) is a biometric technology that identifies or verifies an individual based on unique vein patterns. Region of interest (ROI) extraction is one of the essential steps in FVRS. Current ROI extraction methods cannot extract an accurate ROI for a finger vein image with non-uniform background illumination. In this paper, we propose a new ROI extraction method that is immune to non-uniform background illumination. To detect the edge of the finger for the ROI extraction, we utilise watershed segmentation with distance transform and Canny edge detector. Experimental results show that the proposed ROI extraction method can extract consistent ROI from a finger vein image with non-uniform background illumination.

In breast X-ray imaging, breast texture has been characterized by a radial noise power spectrum (NPS) that has an inverse power-law shape with exponent β. The technique to estimate the radial power-law coefficient β is typically based on averaging 2-dimensional noise power spectra (NPS), calculated from partly overlapping image regions each weighted by a suitable window function. The linear regression applied over a selected frequency range to the logarithm of the 1- dimensional NPS as a function of the logarithm of the radial frequencies, gives β. For each step in this process, several alternative techniques have been proposed. This paper investigates the effect of image region of interest (ROI) size, image data windowing and alternative ways to determine radial frequency in terms of bias, variance and root mean square error (RMSE) in the estimated β. The effects of these three factors were analytically derived and evaluated using synthetic images with known β varying from 1 to 4 to cover the range of textures encountered in 2D and 3D breast X-ray imaging. Our results indicate that the RMSE in estimated β is smallest when the ROIs are multiplied with an appropriate window function and either no radial averaging or radial averaging with small frequency bins is applied. The ROI size yielding the smallest RMSE depends on several factors and needs to be validated with numerical simulations. In clinical practice however, there might be a need to compromise in the choice of the ROI size to balance between the RMSE magnitudes inherent to the applied β estimation technique and encompass the breast texture range so as to obtain an accurate shape of the NPS. When using 2.56 cm x 2.56 cm ROI sizes, applying a 2D Hann window and no radial frequency averaging, the RMSE in the estimated β ranges from 0.04 to 0.1 for true β values equal to 1 and 4. While many subtleties in real images were not modeled to simplify the mathematics in deriving our results, this work is illustrative in demonstrating the limits of commonly used algorithm steps to estimate accurate β values.

Objective To investigate the changes in physique and the bone age, and the correlation between the changes in cardiac structure and function and the bone age index (BAI) in atrial septal defect (ASD) children. Methods The experimental group included 48 cases of ASD patients, and 30 cases of healthy children were assigned as the control group; the children of both groups were measured for height and weight.Philips ie33 ultrasonic detector was used to detect the indicators of cardiac structure and function, and Philips digital X-ray machine was used to radiograph the left hand and the wrist.Then the bone age was assessed in order to calculate the BAI.Fourteen cases of ASD patients who underwent repairing surgery were measured for orifice area in surgery.The differences in physique and the bone age between the 2 groups were analyzed, and Pearson correlation analysis method was used to observe the correlation between the cardiac structure and function indicators, defect area and BAI in the experimental group. Results There was no significant difference in the age, height, bone age(t=-0.02, -1.31, -1.69, all P>0.05), while the weight and BAI were significantly different between the 2 groups(t=-2.28, -9.06, all P 0.05). The height and BAI were significantly different in patients with different defect size(t=2.561, 2.191, all P 0.05). The defect size, defect size/atrial septal stretched diameter, PASP were all negatively correlated with BAI(r=-0.349, P<0.05; r=-0.412, P<0.01; r=-0.539, P<0.01). The defect area was positively related to the defect size in 14 cases of children with ASD underwent surgery(r=0.599, P<0.05), and the defect area was negatively correlated with BAI(r=-0.655, P<0.05). Conclusions The physical development in ASD patients evidently lagged behind the healthy children, particularly for weight.The BAI of ASD patients is significantly smaller than that of the healthy children, in other words, the growing speed of bone in ASD patients is significantly slower than that of the healthy children at the same age.The lagging extent of physical development and the bone age are related to the PASP and defect size.PASP has more influence on the height, yet the defect size has influence on height and weight of ASD children.There is no correlation between physical development and the bone age with the course of disease. Key words: Congenital atrial septal defect; Pulmonary hypertension; Defect size; Growth and development; Bone age index

In x-ray imaging methods, such as synchrotron radiation microangiography, the x-ray intensity has become more important in recent years for real-time dynamic observations to evaluate temporal changes in samples. Many synchrotron radiation facilities use x-rays monochromated by diffraction from perfect Si crystals to improve the spatial resolution of x-ray images and obtain detailed information about a sample. In this paper, monochromatic synchrotron x-ray images were acquired using Si crystals lapped with abrasives to enhance the x-ray intensity using white synchrotron radiation x-rays for observing dynamic changes in samples. The x-ray intensity, spatial resolution, and contrast noise ratio (CNR) in the acquired x-ray images were quantitatively evaluated using a state-of-the-art high-spatial-resolution detector. The x-ray intensity was substantially increased by a factor of ∼8 when a lapped Si crystal was used. When the lapped Si crystal was used, the spatial resolution of x-ray images in the diffraction-plane direction was ∼70% lower than when an etched Si crystal was used at a spatial resolution of 10 lp/mm. By contrast, the CNR in x-ray images, which is important for observing the interior of a sample, increased threefold when a contrast agent containing iodine at a concentration of 38 wt. % was used. It was confirmed that the combination of white synchrotron radiation x-rays and a lapped crystal produces an intense monochromatic x-ray, providing an important evaluation for the use of optics for each research purpose.

Objective To explore the application of the automatic bone age assessment of BoneXpert software in Children and adolescent of China(Shanghai). Methods Left hand and wrist radiographs of 434 cases of children from trauma(264 boys and 170 girls) were obtained from Jan.2010 to Dec.2013.Bone age was assessed by BoneXpert software and 40 radiographs were randomly chosen and re-evaluated after a week. Results Seven images were rejected by BoneXpert, so the efficiency of the software was 98.4% and it takes only 14.5 s for every image.Sample assessments by two times are exactly the same.As to BoneXpert software, there were statistical differences between bone age and chronological age in 8 groups: 7, 8, 9, 11 years old boys and 2, 3, 9, 11 years old girls(P<0.05) out of 26 groups, and the average difference was about 1 s. The following modifications suggested that 0.57, 0.79, 0.93, -0.38 and -0.22, 0.30, 0.37, 0.59 years could be added respectively for the groups of boys aged 7, 8, 9, 11 and girls aged 2, 3, 9, 11 years old according to their average differences between the bone age and the chronological age. Conclusions The BoneXpert method for automated determination of skeletal maturity which evaluates bone age objectively and quickly can be applied clinically after slight adjustment in some age groups.BoneXpert software is 100 percent automatic and could eliminate the subjective evaluation inaccuracy. Key words: Bone age; BoneXpert; Greulich-Pyle atlas; Child; Adolescent

For trauma and orthopedic surgery, maneuvering a mobile C-arm fluoroscope into a desired position to acquire an X-ray is a routine surgical task. The precision and ease of use of the C-arm becomes even more important for advanced interventional imaging techniques such as parallax-free X-ray image stitching. Today's standard mobile C-arms have been modeled with only five degrees of freedom (DOF), which definitely restricts their motions in 3-D Cartesian space. In this paper, we present a method to model both the mobile C-arm and patient's table as an integrated kinematic chain having six DOF without constraining table position. The closed-form solutions for the inverse kinematics problem are derived in order to obtain the required values for all C-arm joint and table movements to position the fluoroscope at a desired pose. The modeling method and the closed-form solutions can be applied to general isocentric or nonisocentric mobile C-arms. By achieving this we develop an efficient and intuitive inverse kinematics-based method for parallax-free panoramic X-ray imaging. In addition, we implement a 6-DOF C-arm system from a low-cost mobile fluoroscope to optimally acquire X-ray images based solely on the computation of the required movement for each joint by solving the inverse kinematics on a continuous basis. Through simulation experimentation, we demonstrate that the 6-DOF C-arm model has a larger working space than the 5-DOF model. C-arm repositioning experiments show the practicality and accuracy of our 6-DOF C-arm system. We also evaluate the novel parallax-free X-ray stitching method on phantom and dry bones. Using five trials, results show that parallax-free panoramas generated by our method are of high visual quality and within clinical tolerances for accurate evaluation of long bone geometry (i.e., image and metric measurement errors are less than 1% compared to ground-truth).

Dual-energy X-ray imaging is an important method of medical imaging, capable of not only obtaining spatial information of imaging object but also disclosing its chemical components, and has many applications in clinic. The current computation methods of dual-energy imaging are still based on the model of mono-energy spectrum imaging with some linear calibration, while they are incapable to reflect correctly the physical characteristics of dual-energy imaging and obstruct deeper research in this field. The article presents a new medical X-ray imaging model in accordance with physics of imaging and its corresponding computational method. The computation process includes two steps: first, to compute two attenuation parameters that have clear physical meaning: equivalent electron density and attenuation parameter of photoemission; then to compute the components of high- and low-density mass through a group of simple equation with two variables. Experiments showed that such method has quite a satisfactory precision in theory, that is, the solutions of parameters under different exposure voltages and thickness of tissue for several main tissues of human body are much low in deviations, whose quotient of standard deviation divided by mean are mostly under 0.1%, and at most 0.32%. The method provides not only a new computational way for dual-energy X-ray imaging, but also a feasible analysis for its nature. In addition, the method can be used to linearly rectify data of dual-energy CT and analyze the chemical component of reconstructed object by means of parameters clear in physics.

Objective To compare the TW2, TW2CH and TW3 methods in Chinese girls with idiopathic precocious puberty (IPP) for the radius ulna and short bones (RUS) bone age. Methods 55 girls (aged from 3.2 to 9.9 years) with idiopathic precocious puberty were admitted in the Department of Pediatrics and Gynecology and Obstetrics, West China Second University Hospital from January 1995 to August 2002 as the test group. Among them, 36 cases started breast development before age 8 (aged from 1.50 to 7.90 years). 20 girls had menarche before age 10 (aged from 5.00 to 9.75 years). The control group includes: ① 14 girls started menarche after age 10 (11.45±1.05) years; ②25 girls who started menarche aged from 8 to 10 (9.20±0.67) years with lower weight; ③ 32 girls who started menarche aged from 8 to 10 (9.11±0.74) years with normal weight; ④ 12 girls who started menarche aged from 8 to 10 (9.61±0.66) years with overweight. Their left hand-wrist radiographs taken at their first visit were retrospectively analyzed. Bone age was staged single-blind using the radius ulna and short bones. TW2 London standard radius ulna and short bones (TW2), TW2 in the south of China standard radius ulna and short bones (TW2CH) and TW3 systems were used in bone age estimation. Five decision thresholds were recorded for each system. They were >97th percentile, >90th percentile, >75th percentile, >50th percentile and ≤50th percentile. Results The following four thresholds were relatively high in both sensitivity and specificity: ①>90th percentile of TW2CH (Sen=0.836, Spe=0.915), by which there were 16 cases of missed diagnosis and misdiagnosis, with a diagnosis accuracy of 88.41%; ②>90th percentile of TW3 (Sen=72.73%, Spe=86.75%), by which there were 26 cases of missed diagnosis and misdiagnosis, with a diagnosis accuracy of 81.16%; ③>75th percentile of TW2CH, by which there were 28 cases of missed diagnosis and misdiagnosis, with a diagnosis accuracy of 79.71%; ④>75th percentile of TW3, by which there were 30 cases of missed diagnosis and misdiagnosis, with a diagnosis accuracy of 78.26%. Area under the receiver operating characteristic curve (AUR) with TW2CH: 0.942±0.019 (95% CI 0.905~0.978). Area under the receiver operating characteristic curve with TW3: 0.886±0.028 (95% CI 0.831~0.941). Area under the receiver operating characteristic curve with TW2 is the smallest: 0.766±0.040 (95%CI 0.688~0.843). Conclusion To evaluate bone age and its percentile with TW-RUS system, the TW2CH has the highest value in diagnosing idiopathic precocious puberty. TW3 and TW2 systems are moderate. The TW2 Britisher standard radius ulna and short bones is the lowest. Key words: age determination by skeleton; TW2 method; TW3 method; idiopathic precocious puberty; diagnostic test; receiver operating characteristic (ROC) curve

Frictional experiments of rubber against spherical hard solids were carried out. The contact states between the rubber specimens and the spherical solids were observed by using X-ray imaging method in SPring-8; Beam line 19B2; X-ray energy = 25 keV; Pixcel size of X-ray images = 10 μm. The real time observation by using the brilliant X-ray of the synchrotron was applied to characterize the contact states of opaque rubbers during friction. Under the following conditions, diameter of glass sphere as the mated surface = 3 mm and transverse velocity of the mated surface = 0.3 mm/s, the contacting geometry and frictional force were measured simultaneously, and then relationship between the contact state and the frictional force was investigated. The frictional force shows a correlation with the contact area or the shear stress of the rubber. Consequently, it was summarized that the real time observation during friction using X-ray imaging is very effective to understand the mechanism of rubber friction. The synchrotron radiation experiments were performed at BL19B2 in the SPring-8 with approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal No. 2005B0877).

Objective To evaluate the concordance of artificial rank with single epiphyseal nucleus in skeletal age(SA) assessment between observers and the total concordance. Methods From March 2006 to May 2009, 128 children with central precocious puberty were admitted to the West China Second University Hospital. They were divided into case group (n=61) and control group (n=67). In control group, 6 girls started breast development at age 8. Left hand-wrist X-ray radiographs before therapy were retrospectively blindly analyzed by two doctors with radius, ulna and short bones (RUS) skeletal age of TW2 method. Then the two doctors ranked artificially and calculated skeletal age. Kappa values were calculated and u test was performed in SPSS 13.0. Results ① The Kappa values of the 13 epiphyseal nucleuses were: Radial bone (0.812±0.051), ulnar bone (0.944±0.022), first metacarpal bone(0.925±0.028), metacarpal bone (0.703±0.050), fifth metacarpal bone (0.789±0.042), first proximal phalanx (0.964±0.021), proximal phalanx (0.941±0.026), fifth proximal phalanx(0.887±0.034), middle phalanx (0.917±0.031), fifth middle phalanx (0.919±0.030), first distal phalanx (0.772±0.050), distal phalanx (0.883±0.040), fifth distal phalanx (0.856±0.041). For the 13 Kappa values, u test was performed and P values were all smaller than 0.05. ② Total concordance: Kappa=0.776 and standard error=0.044(u=16.128, P<0.05). Conclusion The concordance of artificial rank with single epiphyseal nucleus in skeletal age assessment between observers is high. In practice work, concordance between observers is developed by regularly training, then diagnostic results are correlated and accuracy is advanced. Key words: age determination by skeleton; TW2 method; concordant evaluation; Kappa value

Backscatter imaging is a reliable method of single-sided X-ray imaging where access may pose limitations on traditional transmission X-ray image capture. Because of physical challenges in its implementation, it has traditionally been regarded as unable to do material discrimination, a capability reserved for dual energy and transmission imaging by industry and academia. This research expanded on a novel method developed at the University of Florida, where a material calibration tool was used to calibrate a Viken Detection Nighthawk BTX in backscatter mode for postprocessing material discrimination. Namely, this novel approach identifies materials potentially found in explosive devices, i.e. lead, copper, steel, and plastic, as well as combinations of these materials through a fusion of filters. This research focused on expanding the previous work to determine if the novel approach worked at distances beyond the original use-based tests, as well as if source beam filtering and hardening would improve material resolution.

Purpose. Optimization of the treatment and diagnostic complex in patients with obstructive jaundice syndrome. Materials and methods. A prospective and retrospective study of the experience of treating 285 patients with obstructive jaundice was conducted. For the diagnosis of obstructive jaundice, the following were used: ultrasound, CT, MRI, MRCP, endo-ultrasound, cholangioscopy. Among the admitted patients, there were 135 men (47.4%) and 150 women (52.6%). The main causes of admission with mechanical jaundice syndrome were as follows: choledocholithiasis in 226 (79.3%), cholangitis in 21 (7.4%), extrahepatic bile duct strictures in 30 (10.5%), and BDS stricture in 8 (2.8%). The main methods of decompression were trans-papillary interventions. Such symptoms of mechanical jaundice as yellowness of the sclera and skin, acholic stool were detected in all patients. Skin itching with characteristic scratches on the body was observed among 98.2% of patients, and epigastric pain was observed only in 12 (4.2%) patients. Blood biochemistry parameters showed significant changes indicative of liver failure. Bilirubin levels ranged from 81 to 752 mmol/L. Results. The effectiveness of trans-papillary endoscopic retrograde interventions in mechanical jaundice was 94%. Post-ERCP pancreatitis was the most common complication in 12 (4.2%) and 93% of cases among men and women, respectively, and resolved spontaneously, requiring only conservative treatment. Bleeding occurred in 5 (1.75%) patients, and in all cases it was associated with trans-papillary endoscopic intervention. Cholangitis developed in 12 (7.4%) patients, in most cases due to incomplete drainage. One case of perforation was also detected (0.35%). Other complications accounted for 1.4% of cases. Patient characteristics associated with an increased risk of pancreatitis included sphincter of Oddi dysfunction (21.7%) confirmed by manometry; ERCP-induced pancreatitis (19%); and recurrent pancreatitis (16.2%). Pain during the procedure was a significant predictor of increased risk of post-ERCP pancreatitis (27%). Independent risk factors for post-ERCP pancreatitis were a history of recurrent pancreatitis; pancreatitis associated with previous ERCP; multiple cannulation attempts, pancreatic cytology, and pain during the procedure. In-hospital mortality was 0.8%. Conclusion. The main methods of biliary decompression are retrograde and antegrade minimally invasive procedures performed for specific indications. Today, the development of new methods of X-ray imaging, interventional endoscopy and laparoscopy allows for more intensive and accurate diagnosis.