Sparse-View CT Reconstruction via Robust and Multi-channels Autoencoding Priors

2018 ◽  
Author(s):  
Minghui Zhang ◽  
Fengqin Zhang ◽  
Qiegen Liu ◽  
Dong Liang
Keyword(s):  
Ct Reconstruction

Maisonneuve fracture

2020 ◽  
Vol 99 (2) ◽  
pp. 77-85
Keyword(s):  
Open Reduction ◽  
Lower Leg ◽  
Fracture Dislocation ◽  
Deltoid Ligament ◽  
Ct Reconstruction ◽  
Distal Fibula ◽  
Ct Examination ◽  
Maisonneuve Fracture ◽  
Fibular Fracture ◽  
Wide Range

Introduction: Maisonneuve fracture (MF) is a generally known entity in ankle trauma. However, details about this type of injury can be found only rarely in the literature. For these reasons we have decided to perform a study on MF epidemiology and pathoanatomy. Methods: The group comprised 70 patients (47 men, 23 women), with the mean age of 48 years, who sustained an ankle fracture-dislocation involving the proximal quarter of the fibula. Ankle radiographs in three views and lower leg radiographs in two views were performed in all patients. A total of 59 patients underwent CT examination in three views, including 3D CT reconstruction in 49 of these patients. MRI was performed in 4 patients. Operative treatment was used in 67 patients; open reduction of the distal fibula into the fibular notch was opted for in 54 of them. Results: The highest MF incidence rate was recorded in the 5th decade in the whole group and in men, while in women the peak incidence was in the 6th decade. After the age of 50, the share of women significantly increased. In 64 cases, the fibular fracture was subcapital, and in 6 cases it involved the fibular head. In 24% of the patients, the fibular fracture was seen only in the lateral radiograph of the lower leg. Widening of the tibiofibular clear space was shown by radiographs in 40 cases. Posterior dislocation of the fibula (Bosworth fracture) and tibiofibular diastasis were recorded in 2 cases each. An injury to the anterior and posterior tibiofibular ligaments was found in all 54 patients with open reduction of the distal fibula. A fracture of the medial malleolus was identified in 27 cases (39%) and a complete lesion of the deltoid ligament in 36 cases (51%); in 7 cases (10%) the medial structures were intact. A fracture of the posterior malleolus occurred in 54 (77%) patients. Osteochondral fracture of the talar dome was diagnosed in 2 patients and compression of the articular surface of the distal tibia in the region of the fibular notch in 1 patient. Conclusion: Maisonneuve fracture includes a wide range of injuries both to bone and ligamentous structures of the ankle. Therefore, CT examination is an indispensable part of assessment of this type of fracture.

Convergence and stability analysis of the half thresholding based few-view CT reconstruction

2020 ◽  
Vol 28 (6) ◽  
pp. 829-847
Author(s):  
Hua Huang ◽  
Chengwu Lu ◽  
Lingli Zhang ◽  
Weiwei Wang
Keyword(s):  
Noise Suppression ◽  
Reconstructed Image ◽  
Reference Image ◽  
Projection Data ◽  
Ct Reconstruction ◽  
Reconstruction Algorithms ◽  
Ill Posed ◽  
Thresholding Algorithm ◽  
The Stability ◽  
Well Posed

AbstractThe projection data obtained using the computed tomography (CT) technique are often incomplete and inconsistent owing to the radiation exposure and practical environment of the CT process, which may lead to a few-view reconstruction problem. Reconstructing an object from few projection views is often an ill-posed inverse problem. To solve such problems, regularization is an effective technique, in which the ill-posed problem is approximated considering a family of neighboring well-posed problems. In this study, we considered the {\ell_{1/2}} regularization to solve such ill-posed problems. Subsequently, the half thresholding algorithm was employed to solve the {\ell_{1/2}} regularization-based problem. The convergence analysis of the proposed method was performed, and the error bound between the reference image and reconstructed image was clarified. Finally, the stability of the proposed method was analyzed. The result of numerical experiments demonstrated that the proposed method can outperform the classical reconstruction algorithms in terms of noise suppression and preserving the details of the reconstructed image.

scholarly journals Validation of iterative CT reconstruction by inter and intra observer performance assessment of artificial lung foci

2020 ◽  
Vol 6 (3) ◽  
pp. 534-537
Author(s):  
Britta König ◽  
Nika Guberina ◽  
Hilmar Kühl ◽  
Waldemar Zylka
Keyword(s):  
Low Dose ◽  
Lung Cancer Screening ◽  
Artificial Lung ◽  
Observer Performance ◽  
Subjective Perception ◽  
Ct Reconstruction ◽  
Perfect Agreement ◽  
Observer Reliability ◽  
Iterative Ct Reconstruction ◽  
Extension Ring

AbstractWe investigate the suitability of statistical and model-based iterative reconstruction (IR) algorithm strengths and their influence on image quality and diagnostic performance in low-dose computer tomography (CT) protocols for lung-cancer screening procedures. We evaluate the inter- and intra-observer performance for the assessment of iterative CT reconstruction. Artificial lung foci shaped as spheres and spicules made from material with calibrated Hounsfield units were pressed within layered granules in lung lobes of an anthropomorphic phantom. Adaptively, a soft-tissue- and fat- extension ring were attached. The phantom with foci was scanned using standard high contrast, low-dose and ultra lowdose protocols. For reconstruction the IR algorithm ADMIRE at four different strength levels were used. Two ranking tests and Friedman statistics were performed. Fleiss k and modified Cohen’s kneywere used to quantify inter- and intra-observer performance. In conjunction with the standard lung kernel BL75 radiologists evaluated medium to high IR strength, with preference to S4, as suitable for lung foci detection. When varying reconstruction kernels the ranking became more random than with varying phantom diameter. The inter-observer reliability shows poor to slight agreement expressed by k<0 and k=0-0.20 . For the intra-observer reliability non- agreement with kney=0-0.20and moderate agreement with kney=0.60-0.79 for the first ranking test, and almost perfect agreement with kney>0.90 for the second ranking test was observed. In conclusion, our validation suggests radiological preference of medium to high iteration strengths, especially S4, for lung foci detection. An investigation of the correlation between diagnostic experience and the subjective perception of IR reconstructed CT images still needs to be investigated.

High Pitch Helical CT Reconstruction

2021 ◽  
pp. 1-1
Author(s):  
John W. Hayes ◽  
Juan Montoya ◽  
Adam Budde ◽  
Chengzhu Zhang ◽  
Yinsheng Li ◽  
...  
Keyword(s):  
Helical Ct ◽  
Ct Reconstruction ◽  
High Pitch

scholarly journals Using micro-computed tomography to reveal the anatomy of adult Diaphorina citri Kuwayama (Insecta: Hemiptera, Liviidae) and how it pierces and feeds within a citrus leaf

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Javier Alba-Tercedor ◽  
Wayne B. Hunter ◽  
Ignacio Alba-Alejandre
Keyword(s):  
Computed Tomography ◽  
Significant Advance ◽  
Micro Ct ◽  
Diaphorina Citri ◽  
Ct Reconstruction ◽  
Internal Anatomy ◽  
Micro Computed Tomography ◽  
Citrus Leaf ◽  
Teaching Aids ◽  
Adult Feeding

AbstractThe Asian citrus psyllid (ACP), Diaphorina citri, is a harmful pest of citrus trees that transmits Candidatus Liberibacter spp. which causes Huanglongbing (HLB) (citrus greening disease); this is considered to be the most serious bacterial disease of citrus plants. Here we detail an anatomical study of the external and internal anatomy (excluding the reproductive system) using micro-computed tomography (micro-CT). This is the first complete 3D micro-CT reconstruction of the anatomy of a psylloid insect and includes a 3D reconstruction of an adult feeding on a citrus leaf that can be used on mobile devices. Detailed rendered images and videos support first descriptions of coxal and scapus antennal glands and sexual differences in the internal anatomy (hindgut rectum, mesothoracic ganglion and brain). This represents a significant advance in our knowledge of ACP anatomy, and of psyllids in general. Together the images, videos and 3D model constitute a unique anatomical atlas and are useful tools for future research and as teaching aids.

scholarly journals Accuracy comparison of various quantitative [99mTc]Tc-DPD SPECT/CT reconstruction techniques in patients with symptomatic hip and knee joint prostheses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Martin Braun ◽  
Michal Cachovan ◽  
Felix Kaul ◽  
Federico Caobelli ◽  
Markus Bäumer ◽  
...  
Keyword(s):  
Clinical Outcome ◽  
Quantitative Data ◽  
Diagnostic Tools ◽  
Ct Reconstruction ◽  
Knee Prostheses ◽  
Uptake Quantification ◽  
Ct Data ◽  
Joint Prostheses ◽  
Painful Hip ◽  
Xspect Bone

Abstract Background There is a need for better diagnostic tools that identify loose total hip and knee arthroplasties. Here, we present the accuracy of different 99mTc-dicarboxypropandiphosphate ([99mTc]Tc-DPD) SPECT/CT quantification tools for the detection of loose prostheses in patients with painful hip and knee arthroplasties. Methods Quantitative reconstruction of mineral phase SPECT data was performed using Siemens xSPECT-Quant and xSPECT-Bone, with and without metal artefact reduction (iMAR) of CT-data. Quantitative data (SUVmax values) were compared to intraoperative diagnosis or clinical outcome after at least 1 year as standard of comparison. Cut-off values and accuracies were calculated using receiver operator characteristics. Accuracy of uptake quantification was compared to the accuracy of visual SPECT/CT readings, blinded for the quantitative data and clinical outcome. Results In this prospective study, 30 consecutive patients with 33 symptomatic hip and knee prostheses underwent [99mTc]Tc-DPD SPECT/CT. Ten arthroplasties were diagnosed loose and 23 stable. Mean-SUVmax was significantly higher around loose prostheses compared to stable prostheses, regardless of the quantification method (P = 0.0025–0.0001). Quantification with xSPECT-Bone-iMAR showed the highest accuracy (93.9% [95% CI 79.6–100%]) which was significantly higher compared to xSPECT-Quant-iMAR (81.8% [67.5–96.1%], P = 0.04) and xSPECT-Quant without iMAR (77.4% [62.4–92.4%], P = 0.02). Accuracies of clinical reading were non-significantly lower compared to quantitative measures (84.8% [70.6–99.1%] (senior) and 81.5% [67.5–96.1%] (trainee)). Conclusion Quantification with [99mTc]Tc-DPD xSPECT-Bone-iMAR discriminates best between loose and stable prostheses of all evaluated methods. The overall high accuracy of different quantitative measures underlines the potential of [99mTc]Tc-DPD-quantification as a biomarker and demands further prospective evaluation in a larger number of prosthesis.

scholarly journals Phantom and clinical assessment of small pulmonary nodules using Q.Clear reconstruction on a silicon-photomultiplier-based time-of-flight PET/CT system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhifang Wu ◽  
Binwei Guo ◽  
Bin Huang ◽  
Xinzhong Hao ◽  
Ping Wu ◽  
...  
Keyword(s):  
Time Of Flight ◽  
Pulmonary Nodules ◽  
Medium Size ◽  
Ct Reconstruction ◽  
Reconstruction Algorithms ◽  
Silicon Photomultiplier ◽  
Standardized Uptake Values ◽  
Pet Ct ◽  
Quantification Accuracy ◽  
Small Pulmonary Nodules

AbstractTo evaluate the quantification accuracy of different positron emission tomography-computed tomography (PET/CT) reconstruction algorithms, we measured the recovery coefficient (RC) and contrast recovery (CR) in phantom studies. The results played a guiding role in the partial-volume-effect correction (PVC) for following clinical evaluations. The PET images were reconstructed with four different methods: ordered subsets expectation maximization (OSEM), OSEM with time-of-flight (TOF), OSEM with TOF and point spread function (PSF), and Bayesian penalized likelihood (BPL, known as Q.Clear in the PET/CT of GE Healthcare). In clinical studies, SUVmax and SUVmean (the maximum and mean of the standardized uptake values, SUVs) of 75 small pulmonary nodules (sub-centimeter group: < 10 mm and medium-size group: 10–25 mm) were measured from 26 patients. Results show that Q.Clear produced higher RC and CR values, which can improve quantification accuracy compared with other methods (P < 0.05), except for the RC of 37 mm sphere (P > 0.05). The SUVs of sub-centimeter fludeoxyglucose (FDG)-avid pulmonary nodules with Q.Clear illustrated highly significant differences from those reconstructed with other algorithms (P < 0.001). After performing the PVC, highly significant differences (P < 0.001) still existed in the SUVmean measured by Q.Clear comparing with those measured by the other algorithms. Our results suggest that the Q.Clear reconstruction algorithm improved the quantification accuracy towards the true uptake, which potentially promotes the diagnostic confidence and treatment response evaluations with PET/CT imaging, especially for the sub-centimeter pulmonary nodules. For small lesions, PVC is essential.

Guided image filtering based ℓ0 gradient minimization for limited-angle CT image reconstruction

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Tianyi Wang ◽  
Chengxiang Wang ◽  
Kequan Zhao ◽  
Wei Yu ◽  
Min Huang
Keyword(s):  
Iteration Process ◽  
Real Data ◽  
Image Filtering ◽  
Reconstruction Technique ◽  
Ct Reconstruction ◽  
Imaging Device ◽  
Practical Applications ◽  
Guided Image Filtering ◽  
Simultaneous Algebraic Reconstruction Technique ◽  
Limited Angle

Abstract Limited-angle computed tomography (CT) reconstruction problem arises in some practical applications due to restrictions in the scanning environment or CT imaging device. Some artifacts will be presented in image reconstructed by conventional analytical algorithms. Although some regularization strategies have been proposed to suppress the artifacts, such as total variation (TV) minimization, there is still distortion in some edge portions of image. Guided image filtering (GIF) has the advantage of smoothing the image as well as preserving the edge. To further improve the image quality and protect the edge of image, we propose a coupling method, that combines ℓ 0 {\ell_{0}} gradient minimization and GIF. An intermediate result obtained by ℓ 0 {\ell_{0}} gradient minimization is regarded as a guidance image of GIF, then GIF is used to filter the result reconstructed by simultaneous algebraic reconstruction technique (SART) with nonnegative constraint. It should be stressed that the guidance image is dynamically updated as the iteration process, which can transfer the edge to the filtered image. Some simulation and real data experiments are used to evaluate the proposed method. Experimental results show that our method owns some advantages in suppressing the artifacts of limited angle CT and in preserving the edge of image.

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