Visual grading evaluation of reconstruction methods and dose optimisation in abdominal Computed Tomography

Kataria, Bharti

doi:10.3384/diss.diva-160928

Cited by 3 publications

(8 citation statements)

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“…Despite the variation in methodology, the authors have come to quite similar conclusions. It is known that subjective evaluations are prone to observer bias ( 1 ) but are clinically more relevant than phantom studies. Therefore, choice of comparison type is important.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, choice of comparison type is important. Simultaneous viewing of images pairwise tends to increase the ability to identify subtle differences in image quality between the images ( 1 ) , which may not be apparent when viewing the images separately. On the other hand, separate image assessment would be a better choice in lesion detection studies where the image depicting the lesion best might otherwise influence the observer if pairwise comparisons are performed.…”

Section: Discussionmentioning

confidence: 99%

“…The second loop consists of iterations that reduce noise by means of statistical modelling performed in the image domain. The iteration process is speeded up as consequent iterations compare ‘current data sets’ with the master 3D volume, rendering the computationally intensive backward and forward projections unnecessary ( 1 ) ( Figure 1 ).…”

Section: Methodsmentioning

confidence: 99%

“…Modern computed tomography (CT) scanners are equipped with several dose reduction features such as tube current modulation, automatic tube voltage selection, filtration, dynamic shielding and post-processing methods such as iterative reconstruction (IR) ( 1 ) . Due to lack of computational power, the implementation of IR in clinical applications was not possible in the infancy of CT.…”

Section: Introductionmentioning

confidence: 99%

“…There are two main groups of IR algorithms: the statistical/hybrid IR and model-based IR (MBIR) algorithms. The statistical/hybrid algorithms mainly reduce noise while the MBIR algorithms, in addition to their denoising properties, also correct for image degrading effects by incorporating several geometric, optic and system models ( 1 , 2 , 4 , 5 ) . The strengths and weaknesses of noise reduction strategies are discussed by Ehman et al .…”

Section: Introductionmentioning

confidence: 99%

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Image Quality and Potential Dose Reduction Using Advanced Modeled Iterative Reconstruction (Admire) in Abdominal Ct - A Review

Kataria

Althén

Smedby

et al. 2021

Radiation Protection Dosimetry

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Traditional filtered back projection (FBP) reconstruction methods have served the computed tomography (CT) community well for over 40 years. With the increased use of CT during the last decades, efforts to minimise patient exposure, while maintaining sufficient or improved image quality, have led to the development of model-based iterative reconstruction (MBIR) algorithms from several vendors. The usefulness of the advanced modeled iterative reconstruction (ADMIRE) (Siemens Healthineers) MBIR in abdominal CT is reviewed and its noise suppression and/or dose reduction possibilities explored. Quantitative and qualitative methods with phantom and human subjects were used. Assessment of the quality of phantom images will not always correlate positively with those of patient images, particularly at the higher strength of the ADMIRE algorithm. With few exceptions, ADMIRE Strength 3 typically allows for substantial noise reduction compared to FBP and hence to significant (≈30%) patient dose reductions. The size of the dose reductions depends on the diagnostic task.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Image Quality and Potential Dose Reduction Using Advanced Modeled Iterative Reconstruction (Admire) in Abdominal Ct - A Review

Kataria

Althén

Smedby

et al. 2021

Radiation Protection Dosimetry

Self Cite

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Optimization of photon counting CT for cardiac imaging in patients with left ventricular assist devices: An in‐depth assessment of metal artifacts

Konst,

Ohlsson,

Henriksson

et al. 2024

J Applied Clin Med Phys

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PurposePhoton counting CT (PCCT) holds promise for mitigating metal artifacts and can produce virtual mono‐energetic images (VMI), while maintaining temporal resolution, making it a valuable tool for characterizing the heart. This study aimed to evaluate and optimize PCCT for cardiac imaging in patients during left ventricular assistance device (LVAD) therapy by conducting an in‐depth objective assessment of metal artifacts and visual grading.MethodsVarious scan and reconstruction settings were tested on a phantom and further evaluated on a patient acquisition to identify the optimal protocol settings. The phantom comprised an empty thoracic cavity, supplemented with heart and lungs from a cadaveric lamb. The heart was implanted with an LVAD (HeartMate 3) and iodine contrast. Scans were performed on a PCCT (NAEOTOM Alpha, Siemens Healthcare). Metal artifacts were assessed by three objective methods: Hounsfield units (HU)/SD measurements (DiffHU and SDARTIFACT), Fourier analysis (AmplitudeLowFreq), and depicted LVAD volume in the images (BloomVol). Radiologists graded metal artifacts and the diagnostic interpretability in the LVAD lumen, cardiac tissue, lung tissue, and spinal cord using a 5‐point rating scale. Regression and correlation analysis were conducted to determine the assessment method most closely associated with acquisition and reconstruction parameters, as well as the objective method demonstrating the highest correlation with visual grading.ResultsDue to blooming artifacts, the LVAD volume fluctuated between 27.0 and 92.7 cm3. This variance was primarily influenced by kVp, kernel, keV, and iMAR (R2 = 0.989). Radiologists favored pacemaker iMAR, 3 mm slice thickness, and T3D keV and kernel Bv56f for minimal metal artifacts in cardiac tissue assessment, and 110 keV and Qr40f for lung tissue interpretation. The model adequacy for DiffHU SDARTIFACT, AmplitueLowFreq, and BloomVol was 0.28, 0.76, 0.29, and 0.99 respectively for phantom data, and 0.95, 0.98, 1.00, and 0.99 for in‐vivo data. For in‐vivo data, the correlation between visual grading (VGSUM) and DiffHU SDARTIFACT, AmplitueLowFreq, and BloomVol was −0.16, −0.01, −0.48, and −0.40 respectively.ConclusionWe found that optimal scan settings for LVAD imaging involved using 120 kVp and IQ level 80. Employing T3D with pacemaker iMAR, the sharpest allowed vascular kernel (Bv56f), and VMI at 110 keV with kernel Qr40 yields images suitable for cardiac imaging during LVAD‐therapy. Volumetric measurements of the LVAD for determination of the extent of blooming artifacts was shown to be the best objective method to assess metal artifacts.

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Analysis of image quality and radiation dose in routine adult brain helical and wide-volume computed tomography procedures

Garba

Abba

et al. 2022

Journal of Medical Imaging and Radiation Sciences

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Visual grading evaluation of reconstruction methods and dose optimisation in abdominal Computed Tomography

Abstract: CMIV is acknowledged for the provision and access to leading-edge research infrastructure. Published articles have been reprinted with the permission of the copyright holder.

Cited by 3 publications

References 50 publications

Image Quality and Potential Dose Reduction Using Advanced Modeled Iterative Reconstruction (Admire) in Abdominal Ct - A Review

Image Quality and Potential Dose Reduction Using Advanced Modeled Iterative Reconstruction (Admire) in Abdominal Ct - A Review

Optimization of photon counting CT for cardiac imaging in patients with left ventricular assist devices: An in‐depth assessment of metal artifacts

Analysis of image quality and radiation dose in routine adult brain helical and wide-volume computed tomography procedures

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