Iterative reconstruction, one of the most widely used noise reduction techniques, . Wall area percentage assessment is easily influenced by dose reduction. AJR . This study was aimed to analyze the application value of the filtered back-projection (FBP) reconstruction algorithm of computed tomography (CT) images in laparoscopic-assisted distal gastrectomy. This website shows animations of FBP reconstruction. This study was prospectively conducted on 21 patients with bladder masses. While iterative reconstruction is more complex, it has advantages in that it is capable of dealing with noise and other practical issues by incorporating their expected impact/uncertainty into the reconstruction process. Algebraic Reconstruction Technique (ART) is more attractive when the number of views is limited and when noise is signicant. Unlike analytical reconstruction, iterative techniques solve the inverse problem by first formulating the system equation for the relationship between the object and projection data, as an algebraic equation in the form of a large system . The general iterative reconstruction (IR) algorithms suffer from their heavy calculation burden and other drawbacks. Eur Radiol 1011; 21: 636 - 43. (www.actabiomedica.it). Purpose To assess the impact of iterative reconstruction and filtered back projection (FBP) on image quality in computed tomography (CT)-based forensic age estimation of the medial clavicular epiphysis. All patients were subjected to two scanning protocols: protocol . There are two main types of mathematical algorithms for image reconstruction: analytic reconstruction (filtered back projection) and iterative reconstruction. Methods Unenhanced CT scans of 73 SSNs obtained using the same protocol and reconstructed with both FBP and MBIR algorithms were evaluated by two radiologists. iterative reconstruction improves image quality without the need for more dose can retrospectively improve suboptimal images iterative reconstruction siemens default ir protocols enabled by checking safire/admire box you should now be able to: recognize the available dedicated adult and pediatric protocols and how protocol parameters can be In this technology, a 3D model of the sample is gradually built up over the course of many iterations. This is, of course, a simplified overview of iterative reconstruction without statistical modelling 1,3. Written informed consent was obtained from all patients. Iterative reconstruction: these algorithms involve a feedback process that permits sequential adjustments of an estimated image so that its virtual acquisition corresponds to the raw . Some of the most important procedures are classified as Back-projection, Filtered Back-projection and iterative reconstruction techniques. Each study was reconstructed with filtered back projection (FBP), hybrid iterative reconstruction (iDose 4), and IMR in a diastolic phase. [2]). Purpose To assess the impact of iterative reconstruction and filtered back projection (FBP) on image quality in computed tomography (CT)-based forensic age estimation of the medial clavicular epiphysis. (a) Image noise of 30.0 HU and vessel contrast in the proximal RCA of 464.6 HU. These are extensively used in x-ray imaging. Nance JW Jr, Lv B, Yang H, et al. Slice thickness is 0.5 mm. The extent and severity of motion artifacts have been described for filtered backprojection (FBP) reconstruction. Dental hardware produces streak artifacts on computed tomography (CT) images reconstructed with the standard weighted filtered back projection (wFBP) method. The purpose of this study was to demonstrate the advantage of using MBIR for noise reduction and image quality improvement in low dose chest CT for children with necrotizing pneumonia, over the adaptive statistical iterative reconstruction (ASIR) and . The purpose was to assess radiation dose, image quality, and diagnostic performance of reduced-dose scanning with iterative reconstruction (IR) compared with standard-dose with filtered back projection (FBP) with CT urography for detection of bladder tumor. An introduction to the medical diagnostic technique, Computed Tomography (CT). Input Using the raw data produced by the computed tomographic scanner a standard filtered back projection algorithm is utilized to create a primary image. Results: There were significant effects of . Filtered back projection techniques rely on well-established CT reconstruction techniques ( 35 , 36 ) in which the projection images are "filtered" using a reconstruction kernel and then summed together according to the . PURPOSE To prospectively compare traditional filtered back projection (FBP) and iterative image reconstruction for the evaluation of heavily calcified arteries with coronary computed tomography (CT) angiography. For the IR algorithm, the adaptive statistical iterative reconstruction (ASIR, GE Healthcare, Milwaukee, WI, USA) was used. This video covers the basic principles of CT image reconstruction, and the back projection method. Results The CT numbers and the contrast-to-noise ratios were reported and how they are affected by the kernel choice and strength of iterative reconstruction. Back- projection played an important historical role but is no longer used because of sizable artifacts . Image quality was rated as good. PURPOSE: To evaluate the image quality of an iterative reconstruction algorithm (IRIS) in low-dose chest CT in comparison with standard-dose filtered back projection (FBP) CT. MATERIALS AND METHODS: Eighty consecutive patients referred for a follow-up chest CT examination of the chest, underwent a low-dose CT examination (Group 2) in similar . Coronary CT angiography using iterative reconstruction vs. filtered back projection: evaluation of image quality Acta Biomed. Methods Eighteen patients underwent standard protocol CT KUB at our institution. Traditional filtered back projection (FBP) methods yield noisy images, susceptible to artifacts dependent on the reconstruction filters and radiation doses applied [4], but theoretically iterative reconstruction (IR) allows optimization of dose and image quality [5] through noise and artifact minimization [6]. Europe PMC is an archive of life sciences journal literature. . Patient motion during myocardial perfusion SPECT is a common source of errors. Patients in group A were scanned at 80 kV-150 mAs, and the traditional filtered back projection (FBP) algorithm was employed to reconstruct the images; besides, 80 kV-30 mAs was adopted to scan the patients in group B, and the images were reconstructed by IMR1, IMR2, IMR3, iDose4 (a kind of hybrid iterative reconstruction technology), and FBP . Diagnostic accuracy of coronary CT angiography: comparison of filtered back projection and iterative reconstruction with different strengths. Crossref, Medline, Google Scholar; 13 Singh S, Kalra MK, Hsieh J et al.. Abdominal CT: comparison of adaptive statistical iterative and filtered back projection reconstruction techniques. Adaptive iterative dose reduction 3D (AIDR 3D) vs. filtered back projection: radiation dose reduction capabilities of wide volume and helical scanning techniques on area-detector CT in a chest phantom study - Shinichiro Seki, Hisanobu Koyama, Yoshiharu Ohno, Sumiaki Matsumoto, Hiroyasu Inokawa, Naoki Sugihara, Kazuro Sugimura, 2016 Eur J Radiol 2012;81(7):1483-1487. Reduceddose low-voltage chest CT angiography with sinogram affirmed iterative reconstruction versus standard-dose filtered back projection. Iterative reconstruction reduces abdominal CT dose. Radiology 2013 . OBJECTIVE. For these reasons, iterative methods are . Abstract Iterative reconstruction has been shown to reduce image noise compared with traditional filtered back projection with quantum denoising software (FBP/QDS+) in CT imaging but few comparisons have been made in the same patients without the influence of interindividual factors. Image quality of low-dose CT examinations in 80 patients. CT images have been reconstructed from raw data using filtered back projection (FBP) since the inception of the modality. Methods: Sixty-two LD-CTE exams were performed. Purpose: The purpose of this study was to compare observer performance for detection of intestinal inflammation for low-dose CT enterography (LD-CTE) using scanner-based iterative reconstruction (IR) vs. vendor-independent, adaptive image-based noise reduction (ANLM) or filtered back projection (FBP). Traditional filtered back-projection (FBP) has given way to novel iterative reconstruction algo- rithms, and its use has increasingly been employed. Fourier transforms of the projections are first calculated and multiplied by the cut-off 1D version of | rk | (the ramp filter). In addition, several studies have revealed that the latest IR technique, model-based iterative reconstruction (MIR), produces diagnostically acceptable images in low-dose chest CT in comparison with conventional filtered back projection (FBP) and hybrid iterative reconstruction (HIR), which were previously used algorithms ( 4, 5, 6 ). Image quality analysis The reconstructed CTA images were transferred to workstations Image reconstruction loop Visualization of critical soft-tissue anatomic structures was significantly improved by using iterative metal artifact reduction compared with weighted filtered back-projection (median, 1 1.5 versus 3 1.3, P < .001), with improvement in the worst visualized anatomic structure in 88% (60/68) of patients. Iterative Reconstruction Slow compared to filtered back projection Busey JM, et al. Mean pixel attenuation value and standard deviation (SD) were measured in the left ventricle and left main coronary artery. The 120 kVp and ASIR 40% are the current CCTA protocols used in the institution where the phantom was scanned. The Filtered backprojection or Filtered back projection is an algorithm to reconstruct 2D image data from a set of available 1D projections. Iterative reconstruction (IR) technique is an important radiation dose reduction strategy and could achieve radiation dose reduction without significant compromise of image quality, compared with filtered back projection (FBP) of routine radiation dose ( 1, 2, 3, 4, 5, 6, 7 ). . MATERIALS AND METHODS The study had institutional review board approval and was HIPAA compliant. Filtered back projection (FBP) and two different IR strengths of ASIR 40% and 60% were investigated. improvements, compared to iterative reconstruction. Traditionally, reconstructions are made using methods that are based on filtered back-projection (FBP), such as the three-dimensional cone-beam reconstruction algorithm developed by Feldkamp . Filtered back projection (FBP) Subjective . Part 2. Conclusions Example showing differences between filtered backprojection (right half) and iterative reconstruction method (left half) Iterative reconstruction refers to iterative algorithms used to reconstruct 2D and 3D images in certain imaging techniques. Top, abdomen of 47-year-old man with suspected metastasis (window width, 500 HU; level, 100 HU). Filtered Back-projection is a mathematically equivalent process to that described above. To evaluate the differences between filtered back projection (FBP) and model-based iterative reconstruction (MBIR) algorithms on semi-automatic measurements in subsolid nodules (SSNs). purposeto estimate potential dose reduction in abdominal ct by visually comparing images reconstructed with filtered back projection (fbp) and strengths of 3 and 5 of a specific mbir.material and methodsa dual-source scanner was used to obtain three data sets each for 50 recruited patients with 30, 70 and 100% tube loads (mean ctdivol 1.9, 3.4 Left, filtered back projection; right, adaptive iterative dose reduction 3D. Advanced non-linear iterative reconstruction (IR) algorithms have been introduced by all vendors as an alternative to traditional, linear filtered back projection (FBP) reconstruction ().FBP is a simple reconstruction technique that requires relatively little computational processing, but is associated with higher noise and poor contrast resolution. Purpose To perform a preliminary evaluation of an iterative metal artifact reduction (IMAR) technique to assess its ability to improve anatomic visualization over wFBP in patients with . Current efforts are being made to move toward lower dose CT scanning, although image noise can be a rate-limiting step due to the use of filtered back projection (FBP) for image reconstruction in CT simulation (CT-SIM) datasets. This video presents in detail the Filtered Back Projection (FBP) algorithm for the reconstruction of the CT images. The inverse Fourier transform of the result is then calculated and back-projected to create the image. Inserts containing line-pair patterns and contrast detail patterns for three different materials were scored by three observers. The filtered sinogram shown above can be back-projected from all views resulting in accurate image reconstruction of the object as shown in this quick video. Created by. with standard low-dose technique and with 30 % reduced dose, using both iterative reconstruction and filtered back projection. Recently, deep learning-based reconstruction (DLR) methods have been developed that achieve more dose reduction and faster reconstruction than IR while preserving the image quality and texture. This algorithm is also known as the "Convolution Back Projection". Raw data were reconstructed with FBP and with an iterative algorithm at level 4 . J Comput Assist Tomogr 2014;38:179-184. Filtered back projection is an analytic reconstruction algorithm designed to overcome the limitations of conventional back projection; it applies a convolution filter to remove blurring. Analytical methods like Filtered Back projection excel in speed and accuracy when a large number of projections are available. While filtered back projection is the most commonly used reconstruction technique, statistical iterative reconstruction (SIR) is a new technology allowing for many of the limitations encountered using filtered back projection to be overcome (e.g. The same raw data were reconstructed . Visual Grading Regression (VGR) and weighted kappa (. w) was used to analyze the data. (a, b) Curved-planar reconstruction images of the right coronary artery (RCA) and axial images of the proximal RCA (insets) reconstructed with filtered back projection (a) and adaptive iterative dose reduction (b) algorithms. Model-based iterative reconstruction versus adaptive statistical iterative reconstruction and filtered back projection in liver 64-MDCT: Focal lesion detection, lesion conspicuity, and image noise. Four radiologists made pair-wise image quality assessment using five visual criteria. Epub 2010 Nov 16 FBP is computationally efficient, but the filtering step enhances the noise in the CT image. Coronary CT angiography using iterative reconstructions vs. filtered back projection 79 patients underwent an un-enhanced CT scan for the coronary calcium quantification followed by an angi- Filtered Back-Projection (FBP) is accurate when radiation dose is high and the input sinogram is ideal, but in low dose settings, it is challenged with higher image noise and artifacts. Iterative reconstruction has been shown to reduce image noise compared with traditional filtered back projection with quantum denoising software (FBP/QDS+) in CT imaging but few comparisons have been made in the same patients without the influence of interindividual factors. Pontana F, Duhamel A, Pagniez J, Flohr T, Faivre JB, Hachulla AL, Remy J, Remy-Jardin M. Eur Radiol, (3):636-643 2010 MED: 21080171 Chest computed tomography using iterative reconstruction vs filtered back projection. reconstruction algorithms: Filtered back projection (FBP/QDS+) reconstruction: using QDS+ "a denoising software that may improve image quality."[17] Iterative reconstruction: using AIDR 3D at the standard level. Thus, the innate limitation of the traditional filtered back projection (FBP) reconstruction algorithm hinders further reducing the radiation dose. Filtered Back-projection Direct back-projection results in blurred image Could filter (de-convolve) resulting 2-D image Linear systems theory suggests order of operations unimportant Filter projection profiles prior to back projection Yet another alternative, (and the one that is almost universallyemployed) 11 One potential way to overcome image noise is to employ advanced reconstruction algorithms to maintain the same . Airway luminal volumetry with iterative reconstruction is insusceptible to dose reduction. Analytical Methods - most popular: FBP- Filtered Backprojection 2. All data sets were reconstructed using filtered back projection (FBP) and the following IRTs: adaptive statistical iterative reconstructions (ASIRs) (ASIR-50, ASIR-100) and model-based iterative reconstruction (MBIR). While filtered back projection is the most commonly used reconstruction technique, statistical iterative reconstruction (SIR) is a new technology allowing for many of the limitations encountered using filtered back projection to be overcome[2]. For example, in computed tomography an image must be reconstructed from projections of an object. Iterative Reconstruction (IR) Filtered Back Projection has some limits Various corrections needed Attenuation Compton Scatter Ordered Subsets Expectation Maximization (OSEM) is a common iterative reconstruction algorithm Improve comments on limitations of filtered back projection. 2.4. Image Reconstruction Methods Technical Review Filtered back-projection reconstruction method Traditionally, Feldkamp-Davis-Kress (FDK) filtered back-projection is used in cone-beam CT geometric reconstruction to reconstruct a 3D volume from a series of sequentially acquired 2D X-ray projections. Ilustration showing FBP, Hybrid IR and Model-based IR.svg 617 458; 623 KB. RESULTS: The volume CT dose index was significantly reduced in studies reconstructed with iterative model reconstruction compared with filtered back-projection, (mean, 24.4 3.1 mGy versus 31.1 6.0 mGy, P < .001), while the SNR and contrast-to-noise ratios improved 2-fold ( P < .001). Iterative reconstruction (IR) techniques have existed since the origins of CT scanning 1 but a lack of computing power initially prevented their use in standard clinical practice. Low tube-voltage scanning ( 6 , 7 ) has been used increasingly in clinical practice with the merging of iterative reconstruction techniques and automatic tube current modulation technology. Additional systolic phase reconstructions were obtained for TCM studies. The scans were reconstructed using all available filtered back projection body kernels and with iterative reconstruction techniques. Iterative reconstruction has been shown to reduce image noise compared with traditional filtered back projection with quantum denoising software (FBP/QDS+) in CT imaging but few. Methods and materials CT of the clavicle was performed in 19 patients due to forensic reasons (70 mAs/140 kVp). Purpose To prospectively assess radiation dose, image quality, and diagnostic performance of computed tomography (CT) urography for detection of urothelial carcinomas by performing reduced-dose scanning with iterative reconstruction (IR) compared with standard-dose scanning with filtered back projection (FBP). Various reconstruction algorithms have been proposed since the introduction of Compton cameras [2], most of which are iterative algorithms [3], [4] since direct reconstruction is more difcult to implement in Compton imaging than traditional computed tomography, in which lter back-projection has found great success. . . In this paper, an . First apply a fast 1D sharpening filter in the projection space, and then perform a backprojection operation to map the data back along the rays which over which it was acquired. In recent years, iterative reconstruction has been used increasingly in reconstruction of myocardial perfusion SPECT images and has been shown to be more accurate than FBP even in cases of incomplete . sensitivity, specificity and diagnostic accuracy were 96%, 97% and 96% in group a vs. 100%, 99% and 99% in group b. conclusion: accuracy in diagnosing pediatric acute appendicitis was maintained in contrast-enhanced abdominopelvic ct scans that incorporated iterative reconstruction technique, despite reductions in mean ctdi vol and ssde by nearly The purpose of this study is to compare image quality and radiation dose between iterative reconstruction and filtered back projection (FBP) reconstruction algorithms in 256-MDCT coronar. It was, up until recently the primary method in cross-sectional imaging reconstruction. Methods and materials CT of the clavicle was performed in 19 patients due to forensic reasons (70 mAs/140 kVp). 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