Quality evaluation of image‐based iterative reconstruction for CT: Comparison with hybrid iterative reconstruction

Kawashima, Hiroki; Ichikawa, Katsuhiro; Matsubara, Kosuke; Nagata, Hiroji; Takata, Takushi; Kobayashi, Satoshi

doi:10.1002/acm2.12597

Cited by 30 publications

(11 citation statements)

References 14 publications

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“…However, it has been reported that IR techniques exhibit nonlinear image properties where the spatial resolution varies depending on the radiation dose and object contrast, and moreover, the property is system dependent, and thus a consistent comparison such as that of this study may be challenging. [27][28][29][30][31]…”

Section: Discussionmentioning

confidence: 99%

Technical Note: Performance comparison of ultra‐high‐resolution scan modes of two clinical computed tomography systems

et al. 2019

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Purpose Two ultra‐high‐resolution (UHR) computed tomography (CT) scanners are clinically available. One is achieved by a CT system with a 0.25 mm × 160 row detector (Detector‐UHR), whereas the other is with a 0.6 mm × 32 row detector with in‐plane comb filtering in a dual source CT (Comb‐UHR). We compared radiation dose efficiencies of the two UHR modes to that of a routine scan mode (RS), using physical image quality measures for an assumed condition of abdominal CT angiography (CTA). Methods A wire phantom, a 300‐mm cylindrical water bath phantom, and a microdisk phantom were used for measuring the modulation transfer function (MTF), noise power spectrum (NPS), and slice sensitivity profiles (SSP), respectively, at CTDIvol of 20 mGy. Images with minimal slice thicknesses were reconstructed by filtered back projection methods. System performance functions (SPF2) based on the prewhitening theorem were calculated by dividing MTF2 by NPS measurements. The ideal observer's detectability index (d'2) was also estimated for a task corresponding to a 1‐mm diameter vessel. Furthermore, a bar‐pattern phantom placed in a water phantom resembling an adult abdomen was scanned, and the visibility of the bars was observed. Results System performance function (SPF2) results showed that Comb‐UHR has a 70% dose efficiency compared to RS and provides better than twofold SPF2 compared to Detector‐UHR. The d'2 values of Detector‐UHR, Comb‐UHR, and RS were 6.5, 14.7, and 16.0, respectively. Although the bar‐pattern phantom images were consistent with the SPF results, bar widths < 1.0 mm for Detector‐UHR and < 0.75 mm for Comb‐UHR and RS were not resolved. Conclusions Though both the UHR modes exhibited system performances extending to 2.6 cycles/mm, they appeared not to be advantageous compared to RS in the conditions applicable to abdominal CTA, because of their insufficient dose efficiencies.

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Section: Discussionmentioning

confidence: 99%

Technical Note: Performance comparison of ultra‐high‐resolution scan modes of two clinical computed tomography systems

et al. 2019

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“…In the treatment of bladder cancer, it is necessary to frequently check the blood routine and biochemical indicators of the patient [19]. Ceramide can induce cell apoptosis, and its synthetase can generate glucosylceramide by catalyzing sugar groups and combining with ceramide [20][21][22], while glucosylceramide can promote cell proliferation and reduce the therapeutic effect of anticancer drugs [23].…”

Section: Discussionmentioning

confidence: 99%

Multislice Spiral Computed Tomography under Hybrid Iterative Reconstruction Algorithm in Staging Diagnosis of Bladder Cancer and Ceramide Glycosylation

Liu

Jiang

2021

Scientific Programming

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This study was to discuss the application of multislice spiral computed tomography (CT) in the staging diagnosis of bladder cancer and the effect of ceramide glycosylation. The hybrid iterative reconstruction algorithm was applied. Immunohistochemistry and western blot were used to detect the normal bladder tissues (30 cases) of GCS in group 1 (100 cases) and group 2. The scanned images of all the research objects were obtained, the images with the iterative reconstruction algorithm were reconstructed, and statistical analysis on the CT value under the algorithm was conducted. The results showed that the image quality, blood vessel sharpness, average image score, signal-to-noise ratio, and radiation dose after the spiral CT and iterative reconstruction algorithm all increased, while the noise value decreased. The optical density value of glucosylceramide synthase in group 2 patients increased by 71%, and the optical density value of group 1 increased by 29%. The optical density expression of glucosylceramide synthase in group 1 patients was significantly higher than that in the control group, and there was a statistical difference between the two ( P < 0.05 ). Among the results of multislice spiral CT for tumor staging, the lesions larger than 5 cm and in the range of 1.1–2 cm in diameter were more sensitive. In 41 patients, there were multiple lesions. A total of 142 cancer lesions were found. The diameter of the tissue ranged from 0.5 to 6.8 cm, with an average diameter of 2.03 ± 0.35 cm. The optical density of glucosylceramide synthase in the group 1 was 5526, and the optical density in group 2 was 2576. The OD expression of GCS in group 1 was greatly higher in contrast to that in group 2, and there was a statistical difference between the two groups ( P < 0.05 ). The multislice spiral CT examination under this algorithm found that the diagnosis and staging accuracy of lesions with a diameter greater than 5 cm and tumor diameters in the range of 1.1 to 2 cm was higher. The image processed by the hybrid iterative reconstruction algorithm had good effect, high definition, and accuracy.

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“…Iterative reconstruction (IR) algorithms have been widely implemented in clinical computed tomography (CT) systems. The IR algorithm is intrinsically nonlinear, which can cause the spatial resolution to be contrast‐ and noise‐dependent, and it is important to assess the spatial resolution using task‐specific metrics 1–7 . With consideration of IR algorithms, the report of the American Association of Physicists in Medicine Task Group 233 (TG233) introduces advanced performance assessment methods for not only in‐plane ( x ‐ y scan plane) spatial resolution, but also longitudinal ( z ‐axis) spatial resolution (slice sensitivity profile: SSP) 8 .…”

Section: Introductionmentioning

confidence: 99%

“…Using such a small slice increment, a fine‐sampled ESF can be obtained directly from continuous slice images of the edge plane parallel to the x ‐ y scan plane. A 0.1‐mm slice increment for ESF/SSP sampling provides a Nyquist frequency of 5 cycles/mm, which is high enough to determine the presampled MTF 6,9 . That is, we do not need to slant the edge plane as done in the radiography and Chen’s method.…”

Section: Introductionmentioning

confidence: 99%

Technical Note: A simple method for measuring the slice sensitivity profile of iteratively reconstructed CT images using a non‐slanted edge plane

et al. 2021

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Purpose A method for measuring the slice sensitivity profile (SSP) of computed tomography (CT) images reconstructed with iterative reconstruction (IR) algorithms was reported by the AAPM Task Group 233 (TG233). In this method, the phantom plane edge is slightly slanted with respect to the scan plane to obtain a composite oversampled edge‐spread function (ESF). However, it is expected that a fine‐sampled ESF can be obtained directly from images reconstructed with a small slice increment without slanting the edge plane. This study aimed to investigate the validity of using a non‐slanted edge plane. Methods In the proposed non‐slanted edge method, the phantom was positioned so that the plane edge was perpendicular to the longitudinal z‐axis, and images were reconstructed with a 1‐mm slice thickness and 0.1‐mm increment. The mean CT value was obtained in each slice and plotted as a function of slice position along the z‐axis, thereby generating the ESF. The SSP was calculated from the ESF by differentiation. In the TG 233‐recommended slanted edge method, the SSP was obtained by following the procedure described in the TG233 report. To validate the methodology, we first used filtered back projection (FBP) images to compare SSPs obtained using the non‐slanted edge method, slanted edge method, and a standard method using a high‐contrast thin object (coin). Next, for two types of IR algorithms, we compared the SSPs obtained using the non‐slanted and slanted edge methods. Results For the FBP images, the SSP measured using the non‐slanted edge method agreed well with SSPs measured using the coin and slanted edge methods. For the IR images, the SSPs measured using the non‐slanted and slanted edge methods showed good agreement. Conclusions The non‐slanted edge method was demonstrated to be valid. The simplicity and practicality of the method allows routine and accurate determination of the SSP.

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Quality evaluation of image‐based iterative reconstruction for CT: Comparison with hybrid iterative reconstruction

Cited by 30 publications

References 14 publications

Technical Note: Performance comparison of ultra‐high‐resolution scan modes of two clinical computed tomography systems

Technical Note: Performance comparison of ultra‐high‐resolution scan modes of two clinical computed tomography systems

Multislice Spiral Computed Tomography under Hybrid Iterative Reconstruction Algorithm in Staging Diagnosis of Bladder Cancer and Ceramide Glycosylation

Technical Note: A simple method for measuring the slice sensitivity profile of iteratively reconstructed CT images using a non‐slanted edge plane

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