Journal of X-Ray Science and Technology - Volume 27, issue 2

Authors: Dou, Yincong | Li, Meixia | Zhang, Lu | Cheng, Tianming | Lei, Pingchong | Ge, Yinghui

Article Type: Research Article

Abstract: OBJECTIVE: To evaluate the potential of synovial membrane volume measurement by MRI in monitoring the effect of radiation synovectomy on patients of Hemophilic Arthropathy (HA). METHODS: We studied 63 diseased joints of 42 HA patients who received hospitalized services at the Hemophilia Diagnosis and Treatment Center of Henan Provincial People’s Hospital from May 2011 to January 2015. Unenhanced and enhanced MR scanning of each diseased joint was performed simultaneously. The volumes of synovial membrane of 21 joints from 16 patients before and after being treated with 32 P radiation synovectomy (PRS) were measured and compared using image post-processing …software and workstation. Two sample matching t test was conducted to analyze the synovial membrane volumes of the same joint measured by unenhanced and enhanced MR, as well as change of MR enhancement ratio after treatments. RESULTS: The synovial membrane volumes measured by unenhanced versus enhanced MR scanning showed no statistical significance. Significant reduction (t  = 7.831, p  < 0.001) of the synovial membrane volume after treatment (2479.45±46.48 mm3 versus 2983.30±42.87 mm3 before treatment) was observed. MR enhancement ratio of synovial membrane decreased after treatment (0.92±0.06 after vs 1.17±0.07 before treatment) with statistical significance. CONCLUSION: The synovial membrane volume and MR enhancement ratio can be used to monitor patient response to PRS treatment. Show more

Keywords: Hemophilia, osteoarthropathy, secondary hypertrophic, clinical efficacy, magnetic resonance imaging

DOI: 10.3233/XST-180480

Citation: Journal of X-Ray Science and Technology, vol. 27, no. 2, pp. 187-195, 2019

Authors: Lu, Fengqi | Gao, Yu | Kong, Que | Qiao, Peng | Shao, Min | Xie, Min

Article Type: Research Article

Abstract: BACKGROUND: Computed tomography (CT) pulmonary angiography (CTPA) examination has been frequently applied in detecting suspected pulmonary embolism (PE). How to reduce radiation dose to patients is also of concern. OBJECTIVE: To assess the value of using 640-slice CT wide-detector volume scan with adaptive statistical iterative reconstruction (ASIR) algorithm in low-dose CTPA. METHODS: Fifty-eight patients who performed with CTPA were divided into two groups randomly. In the first experimental group (n  = 30), ASIR combined with volume scan were performed on the patients, while in the second conventional group (n  = 28), patients received ASIR combined with conventional spiral …scan. General data including age and body mass index, image quality, pulmonary arterial phase, and radiation dose were analyzed by t test in the two groups. RESULTS: In both groups, all images revealed the 5-order or higher pulmonary arterial branches and fully met the needs for clinical diagnosis. There was no statistical difference in general data between the two groups. In terms of pulmonary phase accuracy, compared with the conventional group, images at pulmonary arterial phase could be captured more accurately in the experimental group. CTDI in the experimental group decreased by 30% compared with that in the conventional group. The actual radiation dose in the experimental group was 1.5 mSv, which is reduced by 53% compared to that in the conventional group. CONCLUSIONS: Compared with the conventional spiral scan, using 640-slice CT volume scan with ASIR in CTPA is more accurate in scanning phase and has lower radiation dose. There is no significant difference in image quality between the two groups. Show more

Keywords: 640-slice CT, wide-detector volume scan, low-dose, CT pulmonary angiography

DOI: 10.3233/XST-180427

Citation: Journal of X-Ray Science and Technology, vol. 27, no. 2, pp. 197-205, 2019

Authors: Hussain, Dildar | Han, Seung-Moo | Kim, Tae-Seong

Article Type: Research Article

Abstract: BACKGROUND: Hip fracture is considered one of the salient disability factors across the global population. People with hip fractures are prone to become permanently disabled or die from complications. Although currently the premier determiner, bone mineral density has some notable limitations in terms of hip fracture risk assessment. OBJECTIVES: To learn more about bone strength, hip geometric features (HGFs) can be collected. However, organizing a hip fracture risk study for a large population using a manual HGFs collection technique would be too arduous to be practical. Thus, an automatic HGFs extraction technique is needed. METHOD: This …paper presents an automated HGFs extraction technique using regional random forest. Regional random forest localizes landmark points from femur DXA images using local constraints of hip anatomy. The local region constraints make random forest robust to noise and increase its performance because it processes the least number of points and patches. RESULTS: The proposed system achieved an overall accuracy of 96.22% and 95.87% on phantom data and real human scanned data respectively. CONCLUSION: The proposed technique’s ability to measure HGFs could be useful in research on the cause and facts of hip fracture and could help in the development of new guidelines for hip fracture risk assessment in the future. The technique will reduce workload and improve the use of X-ray devices. Show more

Keywords: DXA imaging system, hip geometric features, random forest, contour traversing

DOI: 10.3233/XST-180434

Citation: Journal of X-Ray Science and Technology, vol. 27, no. 2, pp. 207-236, 2019

Authors: Jiang, Min | Qu, Zhiping | Sun, Yi

Article Type: Research Article

Abstract: Sparse-view Computed Tomography (CT) has important significance in industrial inspection and medical diagnosis. Mojette transform is a kind of discrete Radon transform that can yield exact reconstructions instead of an approximate solution due to finite Radon sampling. However, the image is iteratively reconstructed pixel by pixel from corner to center, and the image error is proportional to the number of iterations. In this paper, we propose that there exist different sets of projection combinations to recover the original image within the close-to-minimal iterations. And a scheme is given to obtain multiple projection sets, each of which has the same number …of minimum iterations and can recover a CT image with a similar level of small noise but different distributions. These images can be used further to restore the final CT image by counteracting noise with each other. The accuracy and validity of the proposed algorithm are verified by comparison with both other Mojette inversion algorithms and the classical SART algorithm. Show more

Keywords: Radon transform, Mojette transform, close-to-minimal iterations, counteracting-noise, different sets of projection combinations

DOI: 10.3233/XST-180423

Citation: Journal of X-Ray Science and Technology, vol. 27, no. 2, pp. 237-256, 2019

Authors: Tan, Xi | Xiang, Kai | Liu, Liang | Wang, Jing | Tan, Shan

Article Type: Research Article

Abstract: The total variation (TV) regularization has been widely used in statistically iterative cone-beam computed tomography (CBCT) reconstruction, showing ability to preserve object edges. However, the TV regularization can also produce staircase effect and tend to over-smooth the reconstructed images due to its piecewise constant assumption. In this study, we proposed to use the structure tensor total variation (STV) that penalizes the eigenvalues of the structure tensor for CBCT reconstruction. The STV penalty extends the TV penalty, with many important properties maintained such as convexity and rotation and translation invariance. The STV penalty utilizes gradient information more effectively and has a …stronger ability to capture local image structural variation. The objective function was constructed with the penalized weighted least-square (PWLS) strategy and the gradient descent (GD) method was used to optimize the objective function. Besides, we investigated whether the norms involved in the STV penalty affected the reconstruction performance and found that the l 1 -norm gave the better performance than the l 2 -norm and l  ∞ -norm. We also examined performance of the STV penalties constructed using different kernel functions and found that the STV with the Gaussian kernel had the best performance, and the STVs with Uniform, Logistic, and Sigmoid kernels had similar performance to each other. We evaluated our reconstruction method with the STV penalty on computer simulated phantoms and physical phantoms. The results demonstrated that STV led to better reconstruction performance than TV, both visually and quantitatively. For the Catphan 600 physical phantom, the STV1 penalty was 175% and 623% better than the low-dose FDK and the high-dose FDK, and 14% better than the TV penalty at the matched noise level, according to the average contrast-to-noise ratio (CNR ); while for the Compressed Sensing simulation phantom, the peak signal to noise ratio (PSNR ) of reconstructed results using STV1 , STV2 , and STV ∞ were 40.67 dB, 38.72 dB, and 37.40 dB, respectively, all being significantly better than 36.84 dB using TV. Show more

Keywords: CBCT, structure tensor, total variation, image reconstruction, staircase effect

DOI: 10.3233/XST-180419

Citation: Journal of X-Ray Science and Technology, vol. 27, no. 2, pp. 257-272, 2019

Authors: Zhang, Yuan | Zhang, Liyi | Sun, Yunshan

Article Type: Research Article

Abstract: BACKGROUND: In computed tomography (CT), a patient motion would result in degraded spatial resolution and image artifacts. OBJECTIVE: To eliminate motion artifacts, this study presents a method to estimate the motion parameters from sinograms based on extended difference function. METHODS: Based on our previous work, we first divide the projection data into two parts according to view angles and take Radon transform. Then, we calculate the extended difference functions and search for the minimum points. The relative displacements can be determined by the minimum points, and the motion can be estimated by the relationships between the …relative displacements and motion parameters. Finally, we introduce the estimated parameters into the reconstruction process to compensate for the motion effects. RESULTS: The simulation results show that the running times can reduce by about 30% than our previous work. In phantom experiments, the relative mean rotation excursion (RMRE) and relative mean translation excursion (RMTE) of the new method are lower than the conventional Helgason–Ludwig consistency condition (HLCC) based method and comparable to our previous work. Compare with the HLCC method, the root mean square error (RMSE) of the new method also reduces, while the Pearson correlation coefficient (CC) and mean structural similarity index (MSSIM) increase. CONCLUSIONS: The proposed new method yields the improved performance on accuracy of motion estimation with higher computational efficiency, and thus it can produce high-quality images. Show more

Keywords: Computed Tomography (CT), extended difference function, fan-beam, motion estimation, motion artifacts

DOI: 10.3233/XST-180442

Citation: Journal of X-Ray Science and Technology, vol. 27, no. 2, pp. 273-285, 2019

Authors: Gupta, Ruchi | Sinha, Neetu | Kumar, Prem | Bhadani, Punam | Rai, Deependra Kumar | Kumar, Subhash

Article Type: Research Article

Abstract: OBJECTIVE: Intermittent CT fluoroscopic biopsy is a new technology, but has not been studied widely. This study aims to investigate correlation between the radiation dose and fluoroscopic CT exposure factors to establish the low dose parameters for performing percutaneous lung biopsies, as well as the relationship of the mean diameter and depth of lesions with radiation dose, procedure time, success and complication rates. MATERIALS AND METHODS: This is a retrospective study to analyse lung biopsies performed using intermittent CT fluoroscopic technique with 18 G semi-automated coaxial gun on 256 slice scanner. A total of 50 patients were included in …the study. Biopsy was done in three mAs and KVp settings (30 and 70, 10 and 120, 30 and 120, respectively). The statistical data analysis was performed using SPSS Statistics software. RESULTS: Pneumothorax occurred in 22 % of cases. Sampling rate was 98% but histopathological diagnosis was made in 94% cases. Mean procedure time was 30.5±11.1 minutes. Low dose protocol (30 mAs and 70 KVp) had least radiation exposure during biopsy procedure (p  < 0.001) with similar success rate, complications and procedure time (p  > 0.05) in comparison with high dose protocol (10 and 120, 30 and 120 mAs and KVp, respectively). Mean diameter of lesions didn’t correlate with radiation dose, success rate, complications and duration of procedure (p  > 0.05) while significant association was found when depth was correlated with radiation exposure during fluoroscopic biopsy, duration of procedure and complication rates (p  < 0.05) while no association was found with success rates. CONCLUSION: On third generation dual energy source CT scanner, reducing mAs and KVp to 30 and 70 during fluoroscopy biopsy can produce images whose complications and success rates are comparable to high dose CT. In general, intermittent CT fluoroscopy guided lung biopsy has good success rates with acceptable complications, while utilising less radiation dose and procedure time. Show more

Keywords: Computed tomography (CT), intermittent, fluoroscopy, biopsy, lung, radiation, dose length product (DLP)

DOI: 10.3233/XST-180424

Citation: Journal of X-Ray Science and Technology, vol. 27, no. 2, pp. 287-296, 2019

Authors: Xu, Jifei | Zhang, Kun | Wang, Hongyan | Cui, Zhenzhen | Wu, Yi | Wang, Wanqin | Wang, Fan

Article Type: Research Article

Abstract: OBJECTIVE: To explore the clinical application of diffusion-weighted magnetic resonance imaging (DWI) in nasopharyngeal carcinoma (NPC) diagnosis, detection of lymph node metastasis, radiotherapy and prognosis. METHODS: Twenty patients with diagnosed NPC in an early stage of radiotherapy were enrolled in our department between May 2010 and May 2013. T1 and T2 weighted magnetic resonance imaging and DWI of the nasopharynx and neck were performed 1 week before radiotherapy, during radiotherapy at a dose of 60 Gy, and 1 month after radiotherapy. Pertinent measurements and related data were recorded. RESULTS: In comparison with that before radiotherapy, the ADC …value of the nasopharyngeal primary lesion increased significantly during radiotherapy at a dose of 60 Gy and at 1 month after radiotherapy (F = 187.160, P  = 0.000). When the dose of radiotherapy reached 60 Gy, the DWI signals from both the neck and the retropharyngeal lymph nodes were significantly lower than those before radiotherapy. CONCLUSION: DWI can be used for sensitive and accurate diagnosis of lymph node metastasis in the neck and retropharyngeal space, monitoring of the radiotherapy effect in early stages of NPC and development of new medical treatment strategies. Show more

Keywords: Magnetic resonance imaging, nasopharyngeal cancer, radiotherapy

DOI: 10.3233/XST-180441

Citation: Journal of X-Ray Science and Technology, vol. 27, no. 2, pp. 297-306, 2019

Authors: Wang, Yuanjun | Liu, Yu

Article Type: Research Article

Abstract: Gradient based image fusion can more effectively incorporate edge details using structure tensor, which is successfully used in 2D image fusion. In this study, we generalized and applied this gradient based image fusion method into 3D for non-small cell lung cancer PET/CT image fusion. According the characteristic of lung PET/CT images, we proposed a novel 3D structure tensor based feature, which can be used to construct a weighted structure tensor containing important local detail of both PET and CT images. The fusion gradient domain is deduced from a rank one tensor, which is the closest approximation of the weighted structure …tensor in geometry. Based on the fusion gradient domain, final PET/CT fusion image is obtained by solving a Poisson equation. Comparing with the wavelet transform based fusion result, the average information entropy and average gradient measure of proposed fusion method increase 13.5% and 42.3%, respectively. The experimental results show that the proposed fusion method enables to effectively preserve lung vessel structure and sphere-like lesion detail while produces clear, stable and well consistent fusion images. Show more

Keywords: PET/CT image fusion, Gradient domain, Structure tensor, Non-small cell lung cancer

DOI: 10.3233/XST-180451

Citation: Journal of X-Ray Science and Technology, vol. 27, no. 2, pp. 307-319, 2019

Authors: Wang, Zhiqiong | Huang, Yukun | Li, Mo | Zhang, Hao | Li, Chen | Xin, Junchang | Qian, Wei

Article Type: Research Article

Abstract: BACKGROUND: The morbidity of breast cancer has been increased in these years and ranked the first of all female diseases. Computer-aided diagnosis techniques for mammograms can help radiologists find early breast lesions. In mammograms, the degree of malignancy of the tumor is not only related to its morphology and texture features, but also closely related to the density of the tumor. However, in the current research on breast masses detection and diagnosis, people usually use the fusion feature of morphology and texture but neglect density, or only the density feature is considered. Therefore, this paper proposes a method to detect …and diagnose the breast mass using fused features with density. METHODS: In this paper, we first propose a method based on sub-region clustering to detect the breast mass. The breast region is divided into sub-regions of equal size, and each sub-region is extracted based on local density feature, after that, an Unsupervised ELM (US-ELM) is used for clustering to complete the mass detection. Second, the feature model is constructed based on the mass. This model is composed of the mass region density feature, morphology feature and texture feature. And Genetic Algorithm is used for feature selection, and the optimized feature model is formed. Finally, ELM is used to diagnose benign or malignant mass. RESULTS: An experiment on the real dataset of 480 mammograms in Northeast China shows that our proposed method can effectively improve the detection and diagnosis accuracy of breast masses, where we obtained 0.9184 precision in detection of breast masses and 0.911 accuracy in diagnosis of breast masses. CONCLUSIONS: We have proposed a mass detection system, which achieves better detection accuracy performance than the existing state-of-art algorithm. We also propose a mass diagnosis system based on the fused features with density, which is more efficient than other feature model and classifier on the same dataset. Show more

Keywords: Density Feature, Extreme Learning Machine, Mammograms, Computer-aided Detection, Computer-aided Diagnosis

DOI: 10.3233/XST-180461

Citation: Journal of X-Ray Science and Technology, vol. 27, no. 2, pp. 321-342, 2019