scholarly journals PARALLEL BEAM NEUTRON COMPUTED TOMOGRAPHY RECONSTRUCTION WITH VARIOUS FILTERS

2016 ◽  
Vol 17 (2) ◽  
pp. 61
Author(s):  
Mardiyanto, Bharoto, Sutiarso Maharani Ahsani Ummi
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Signal To Noise Ratio ◽  
Simple Calculation ◽  
Signal To Noise ◽  
Parallel Beam ◽  
Noise Image ◽  
Tomography Reconstruction ◽  
Computed Tomography Reconstruction ◽  
Neutron Computed Tomography

ABSTRACT PARALLEL BEAM NEUTRON COMPUTED TOMOGRAPHY RECONSTRUCTION WITH VARIOUS FILTERS. This paper presents a simple calculation using the MatLab application code for five different filter functions to obtain the best image quality for parallel beam neutron computed tomography. Shepp-Logan, Ramachandran- Lakshminarayanan, Cosine, Hamming and Hann Filter and without filter were used for a cross-section of a car coil ignitor reconstruction. The reconstruction was also done by varying the number of projections namely 180, 90, 45 and 12. The quality of the image can be determined by viewing the image directly or by using grey level curve to show the signal to noise image. The good images were determined by their signal-to-noise ratio (SNR) value. The high SNR values were obtained from the images which were reconstructed by using hamming and Hann filter. On the other hand the lowest SNR was obtained when the image was reconstructed without any filter. The number of the projections were also influenced the image quality, the more the projection number is used the better the image quality is obtained.

Neutron Computed Tomography Reconstruction Method Using Sparse Projections Based on Weighted Total Difference Minimization

2019 ◽  
Vol 39 (7) ◽  
pp. 0711003
Author(s):  
林强 Qiang Lin ◽  
杨民 Min Yang ◽  
唐彬 Bin Tang ◽  
刘斌 Bin Liu ◽  
霍合勇 Heyong Huo ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Reconstruction Method ◽  
Tomography Reconstruction ◽  
Computed Tomography Reconstruction ◽  
Total Difference ◽  
Neutron Computed Tomography

Quality of Computed Tomography Pulmonary Embolism and Aortic Phase Images Acquired with Power Injection via an Arm Port

2017 ◽  
Vol 22 (2) ◽  
pp. 88-92
Author(s):  
Ryan Verity ◽  
David Leswick ◽  
Brent Burbridge ◽  
Rhonda Bryce ◽  
Hyun Lim
Keyword(s):  
Computed Tomography ◽  
Pulmonary Embolism ◽  
Image Quality ◽  
Thin Section ◽  
Signal To Noise Ratio ◽  
Contrast Injection ◽  
Signal To Noise ◽  
Streak Artifact ◽  
Noise Ratio

Abstract Background: The safety of power-injectable implanted arm ports is well established, but there is insufficient data to conclude that image quality of computed tomography resulting from contrast introduced via the port is of equal quality to images derived from contrast introduced via traditional peripheral access. The objective of this study was to determine whether the image quality of computed tomography pulmonary embolism and computed tomography aorta studies would differ when injecting contrast via an implanted arm port vs a peripheral intravenous site. We hypothesized that injecting via an implanted arm port would produce better-quality images, the result of more appropriate timing and less streak artifact. Methods: Scans from a provincial database search for patients who underwent a computed tomography pulmonary embolism or aorta study with contrast injection via the implanted arm port and thin section images available, were reviewed (pulmonary embolism studies n = 3, aorta studies n = 3). Only a limited number of patients were available for review because there are currently few patients with these ports in place and we limited evaluation to thin section images. Comparison was made with 6 control patients who did not have a port and had received a peripheral arm intravenous contrast injection for these study types. Objective measurements included signal-to-noise ratio and contrast-to-noise ratio of the pulmonary arteries (4 sites) and aorta (2 sites) as appropriate for scan type. Subjective analysis of image quality was performed by 2 radiologists. Results: Although sample size was limited, the implanted arm port group had similar or higher mean signal-to-noise ratio and contrast-to-noise ratio values at all sites. Subjective assessments showed the implanted arm port group to have similar or better opacification and diagnostic confidence; similar or less streak artifact was also observed at each of the sites. Conclusions: These exploratory results suggest that studies with implanted arm port injection can generate high-quality images on both objective and subjective assessment, similar to, or possibly better than, images generated from usual peripheral intravenous access for contrast injection.

scholarly journals Simulated Annealing-Based Image Reconstruction for Patients With COVID-19 as a Model for Ultralow-Dose Computed Tomography

2022 ◽  
Vol 12 ◽  
Author(s):  
Shahzad Ahmad Qureshi ◽  
Aziz Ul Rehman ◽  
Adil Aslam Mir ◽  
Muhammad Rafique ◽  
Wazir Muhammad
Keyword(s):  
Computed Tomography ◽  
Simulated Annealing ◽  
Image Reconstruction ◽  
Image Quality ◽  
Radiation Dose ◽  
Signal To Noise Ratio ◽  
Absolute Error ◽  
Signal To Noise ◽  
X Ray ◽  
Squared Error

The proposed algorithm of inverse problem of computed tomography (CT), using limited views, is based on stochastic techniques, namely simulated annealing (SA). The selection of an optimal cost function for SA-based image reconstruction is of prime importance. It can reduce annealing time, and also X-ray dose rate accompanying better image quality. In this paper, effectiveness of various cost functions, namely universal image quality index (UIQI), root-mean-squared error (RMSE), structural similarity index measure (SSIM), mean absolute error (MAE), relative squared error (RSE), relative absolute error (RAE), and root-mean-squared logarithmic error (RMSLE), has been critically analyzed and evaluated for ultralow-dose X-ray CT of patients with COVID-19. For sensitivity analysis of this ill-posed problem, the stochastically estimated images of lung phantom have been reconstructed. The cost function analysis in terms of computational and spatial complexity has been performed using image quality measures, namely peak signal-to-noise ratio (PSNR), Euclidean error (EuE), and weighted peak signal-to-noise ratio (WPSNR). It has been generalized for cost functions that RMSLE exhibits WPSNR of 64.33 ± 3.98 dB and 63.41 ± 2.88 dB for 8 × 8 and 16 × 16 lung phantoms, respectively, and it has been applied for actual CT-based image reconstruction of patients with COVID-19. We successfully reconstructed chest CT images of patients with COVID-19 using RMSLE with eighteen projections, a 10-fold reduction in radiation dose exposure. This approach will be suitable for accurate diagnosis of patients with COVID-19 having less immunity and sensitive to radiation dose.

scholarly journals Evaluation and Clinical Application of a Commercially Available Iterative Reconstruction Algorithm for CBCT-Based IGRT

2019 ◽  
Vol 18 ◽  
pp. 153303381882305 ◽  
Author(s):  
Weihua Mao ◽  
Chang Liu ◽  
Stephen J. Gardner ◽  
Farzan Siddiqui ◽  
Karen C. Snyder ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Quality Assurance ◽  
Image Quality ◽  
Cone Beam Computed Tomography ◽  
Reconstruction Algorithm ◽  
Cone Beam ◽  
Back Projection ◽  
Filtered Back Projection ◽  
Tomography Reconstruction ◽  
Computed Tomography Reconstruction

Purpose: We have quantitatively evaluated the image quality of a new commercially available iterative cone-beam computed tomography reconstruction algorithm over standard cone-beam computed tomography image reconstruction results. Methods: This iterative cone-beam computed tomography reconstruction pipeline uses a finite element solver (AcurosCTS)-based scatter correction and a statistical (iterative) reconstruction in addition to a standard kernel-based correction followed by filtered back-projection-based Feldkamp-Davis-Kress cone-beam computed tomography reconstruction. Standard full-fan half-rotation Head, half-fan full-rotation Head, and standard Pelvis cone-beam computed tomography protocols have been investigated to scan a quality assurance phantom via the following image quality metrics: uniformity, HU constancy, spatial resolution, low contrast detection, noise level, and contrast-to-noise ratio. An anthropomorphic head phantom was scanned for verification of noise reduction. Clinical patient image data sets for 5 head/neck patients and 5 prostate patients were qualitatively evaluated. Results: Quality assurance phantom study results showed that relative to filtered back-projection-based cone-beam computed tomography, noise was reduced from 28.8 ± 0.3 HU to a range between 18.3 ± 0.2 and 5.9 ± 0.2 HU for Full-Fan Head scans, from 14.4 ± 0.2 HU to a range between 12.8 ± 0.3 and 5.2 ± 0.3 HU for Half-Fan Head scans, and from 6.2 ± 0.1 HU to a range between 3.8 ± 0.1 and 2.0 ± 0.2 HU for Pelvis scans, with the iterative cone-beam computed tomography algorithm. Spatial resolution was marginally improved while results for uniformity and HU constancy were similar. For the head phantom study, noise was reduced from 43.6 HU to a range between 24.8 and 13.0 HU for a Full-Fan Head and from 35.1 HU to a range between 22.9 and 14.0 HU for a Half-Fan Head scan. The patient data study showed that artifacts due to photon starvation and streak artifacts were all reduced, and image noise in specified target regions were reduced to 62% ± 15% for 10 patients. Conclusion: Noise and contrast-to-noise ratio image quality characteristics were significantly improved using the iterative cone-beam computed tomography reconstruction algorithm relative to the filtered back-projection-based cone-beam computed tomography method. These improvements will enhance the accuracy of cone-beam computed tomography-based image-guided applications.

Image Quality Enhancing by Efficient Histogram Equalization

2014 ◽  
Vol 2 (2) ◽  
pp. 47-58
Author(s):  
Ismail Sh. Baqer
Keyword(s):  
Image Quality ◽  
Contrast Enhancement ◽  
Mean Squared Error ◽  
Signal To Noise Ratio ◽  
Histogram Equalization ◽  
Gray Level ◽  
Signal To Noise ◽  
Squared Error ◽  
Noise Ratio

A two Level Image Quality enhancement is proposed in this paper. In the first level, Dualistic Sub-Image Histogram Equalization DSIHE method decomposes the original image into two sub-images based on median of original images. The second level deals with spikes shaped noise that may appear in the image after processing. We presents three methods of image enhancement GHE, LHE and proposed DSIHE that improve the visual quality of images. A comparative calculations is being carried out on above mentioned techniques to examine objective and subjective image quality parameters e.g. Peak Signal-to-Noise Ratio PSNR values, entropy H and mean squared error MSE to measure the quality of gray scale enhanced images. For handling gray-level images, convenient Histogram Equalization methods e.g. GHE and LHE tend to change the mean brightness of an image to middle level of the gray-level range limiting their appropriateness for contrast enhancement in consumer electronics such as TV monitors. The DSIHE methods seem to overcome this disadvantage as they tend to preserve both, the brightness and contrast enhancement. Experimental results show that the proposed technique gives better results in terms of Discrete Entropy, Signal to Noise ratio and Mean Squared Error values than the Global and Local histogram-based equalization methods

scholarly journals Aneurysm Arising at the Origin of a Duplicated Middle Cerebral Artery

2021 ◽  
pp. 446-450
Author(s):  
Jean Roch Alliez ◽  
Luis Manera
Keyword(s):  
Computed Tomography ◽  
Subarachnoid Haemorrhage ◽  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
World Federation ◽  
Treatment Procedure ◽  
3D Computed Tomography ◽  
Ruptured Aneurysms ◽  
Tomography Reconstruction ◽  
Computed Tomography Reconstruction

A duplicated middle cerebral artery (DMCA) is a common anomaly. However, aneurysms arising from the origin of a DMCA are extremely rare. A 22-year-old female was admitted to our hospital with a World Federation of Neurosurgical Societies grade 2 subarachnoid haemorrhage. Four-vessel angiography revealed a DMCA and an aneurysm arising from the origin of this artery. The aneurysm was successfully treated by embolization, and the patient was discharged 2 weeks later. Ruptured aneurysms arising from the origin of a DMCA can be successfully treated by embolization. These aneurysms are small and 3D-computed tomography reconstruction is mandatory to detect them. It is important to preserve the DMCA during the treatment procedure.

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