Effects of automatic tube potential selection on radiation dose index, image quality, and lesion detectability in pediatric abdominopelvic CT and CTA: a phantom study

Brinkley, Michael F.; Ramírez-Giraldo, Juan Carlos; Samei, Ehsan; Frush, D; Choudhury, Kingshuk Roy; Wilson, Joshua M.; Christianson, Olav; Frush, Donald P.

doi:10.1007/s00330-015-3817-x

Cited by 10 publications

(6 citation statements)

References 30 publications

(49 reference statements)

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“…Automated tube voltage selection systems (CARE kV; Siemens Healthineers, Erlangen, Germany; kV assist; GE Healthcare, Milwaukee, Wis) suggest optimal tube voltage and corresponding tube current to attain predefined image quality (ie, a contrast-to-noise ratio with a limitation of an acceptable image noise level) at the lowest radiation dose, on the basis of (a) patient size (an attenuation profile derived from a scout image), (b) clinical tasks (eg, nonenhanced, parenchymal contrast-enhanced CT, and CT angiography), and (c) tube capability (tube current limit at each kilovolt peak). Because lower voltage increases iodine contrast material enhancement, algorithms select lower voltage more frequently for CT angiography and contrast-enhanced CT than for nonenhanced CT. With the use of this algorithm for pediatric CT, radiation dose could be reduced by up to 50%, without loss of diagnostic image quality, in comparison with the use of a standard 120 kVp protocol (43,44).…”

Section: Automated Tube Voltage Selection Tool-man-mentioning

confidence: 99%

Radiation Dose Reduction at Pediatric CT: Use of Low Tube Voltage and Iterative Reconstruction

et al. 2018

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Given the growing awareness of and concern for potential carcinogenic effects of exposure of children to ionizing radiation at CT, optimizing acquisition parameters is crucial to achieve diagnostically acceptable image quality at the lowest possible radiation dose. Among currently available dose reduction techniques, recent technical innovations have allowed the implementation of low tube voltage scans and iterative reconstruction (IR) techniques into daily clinical practice for pediatric CT. The benefits of lowering tube voltage include a considerable reduction in radiation dose and improved contrast on images, especially when an iodinated contrast medium is used. The increase in noise, which is attributed to decreased photon penetration, is a major drawback but is not as severe as that at adult CT because of the small body size of children. In addition, use of IR algorithms can suppress increased noise, yielding wider applicability for low tube voltage scans. However, a careful implementation strategy and methodologic approach are necessary to maximize the potential for dose reduction while preserving diagnostic image quality under each clinical condition. The potential pitfalls of and topics related to these techniques include (a) the effect of tube voltage on the surface radiation dose, (b) the effect of window settings, (c) accentuation of metallic artifacts, (d) deterioration of low contrast detectability at low-dose settings, (e) interscanner variation of x-ray spectra, and (f) a comparison with the use of a spectral shaping technique. Appropriate use of low tube voltage and IR techniques is helpful for radiation dose reduction in most applications of pediatric CT. Online DICOM image stacks are available for this article . RSNA, 2018.

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Section: Automated Tube Voltage Selection Tool-man-mentioning

confidence: 99%

Radiation Dose Reduction at Pediatric CT: Use of Low Tube Voltage and Iterative Reconstruction

et al. 2018

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“…Based on these Each of the scan parameters varied in the present study individually affects dose and image quality. Lower tube voltages reduce dose while increasing noise and contrast [21] and have been reported previously to maintain or improve low-contrast detectability [22,23]. Higher TCM noise levels reduce dose and increase noise and have been found to degrade low-contrast detectability in previous studies [24,25].…”

Section: Discussionmentioning

confidence: 64%

Task-based assessment of neck CT protocols using patient-mimicking phantoms—effects of protocol parameters on dose and diagnostic performance

et al. 2020

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Objectives To assess how modifying multiple protocol parameters affects the dose and diagnostic performance of a neck CT protocol using patient-mimicking phantoms and task-based methods. Methods Six patient-mimicking neck phantoms containing hypodense lesions of 1 cm diameter and 30 HU contrast and one non-lesion phantom were examined with 36 CT protocols. All possible combinations of the following parameters were investigated: 100- and 120-kVp tube voltage; tube current modulation (TCM) noise levels of SD 7.5, 10, and 14; pitches of 0.637, 0.813, and 1.388; filtered back projection (FBP); and iterative reconstruction (AIDR 3D). Dose-length products (DLPs) and lesion detectability (assessed by 14 radiologists) were compared with the clinical standard protocol (120 kVp, TCM SD 7.5, 0.813 pitch, AIDR 3D). Results The DLP of the standard protocol was 25 mGy•cm; the area under the curve (AUC) was 0.839 (95%CI: 0.790–0.888). Combined effects of tube voltage reduction to 100 kVp and TCM noise level increase to SD 10 optimized protocol performance by improving dose (7.3 mGy•cm) and detectability (AUC 0.884, 95%CI: 0.844–0.924). Diagnostic performance was significantly affected by the TCM noise level at 120 kVp (AUC 0.821 at TCM SD 7.5 vs. 0.776 at TCM SD 14, p = 0.003), but not at 100-kVp tube voltage (AUC 0.839 at TCM SD 7.5 vs. 0.819 at TCM SD 14, p = 0.354), the reconstruction method at 100 kVp (AUC 0.854 for AIDR 3D vs. 0.806 for FBP, p < 0.001), but not at 120-kVp tube voltage (AUC 0.795 for AIDR 3D vs. 0.793 for FBP, p = 0.822), and the tube voltage for AIDR 3D reconstruction (p < 0.001), but not for FBP (p = 0.226). Conclusions Combined effects of 100-kVp tube voltage, TCM noise level of SD 10, a pitch of 0.813, and AIDR 3D resulted in an optimal neck protocol in terms of dose and diagnostic performance. Protocol parameters were subject to complex interactions, which created opportunities for protocol improvement. Key Points • A task-based approach using patient-mimicking phantoms was employed to optimize a CT system for neck imaging through systematic testing of protocol parameters. • Combined effects of 100-kVp tube voltage, TCM noise level of SD 10, a pitch of 0.813, and AIDR 3D reconstruction resulted in an optimal protocol in terms of dose and diagnostic performance. • Interactions of protocol parameters affect diagnostic performance and should be considered when optimizing CT techniques.

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“…The results are in line with previous observations in phantoms and patients after contrast medium administration [12][13][14], underlining that the phantoms simulate the clinical situation adequately. Contrast increase at reduced tube voltage is less pronounced for soft tissues without contrast medium enhancement [15], which may thus limit the suitability of the phantoms for studying tube voltage effects in situations where CT scans are acquired without contrast medium administration.…”

Section: Discussionmentioning

confidence: 99%

3D printing of anatomically realistic phantoms with detection tasks to assess the diagnostic performance of CT images

et al. 2020

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Objectives Detectability experiments performed to assess the diagnostic performance of computed tomography (CT) images should represent the clinical situation realistically. The purpose was to develop anatomically realistic phantoms with low-contrast lesions for detectability experiments. Methods Low-contrast lesions were digitally inserted into a neck CT image of a patient. The original and the manipulated CT images were used to create five phantoms: four phantoms with lesions of 10, 20, 30, and 40 HU contrast and one phantom without any lesion. Radiopaque 3D printing with potassium-iodide-doped ink (600 mg/mL) was used. The phantoms were scanned with different CT settings. Lesion contrast was analyzed using HU measurement. A 2-alternative forced choice experiment was performed with seven radiologists to study the impact of lesion contrast on detection accuracy and reader confidence (1 = lowest, 5 = highest). Results The phantoms reproduced patient size, shape, and anatomy. Mean ± SD contrast values of the low-contrast lesions were 9.7 ± 1.2, 18.2 ± 2, 30.2 ± 2.7, and 37.7 ± 3.1 HU for the 10, 20, 30, and 40 HU contrast lesions, respectively. Mean ± SD detection accuracy and confidence values were not significantly different for 10 and 20 HU lesion contrast (82.1 ± 6.3% vs. 83.9 ± 9.4%, p = 0.863 and 1.7 ± 0.4 vs. 1.8 ± 0.5, p = 0.159). They increased to 95 ± 5.7% and 2.6 ± 0.7 for 30 HU lesion contrast and 99.5 ± 0.9% and 3.8 ± 0.7 for 40 HU lesion contrast (p < 0.005). Conclusions A CT image was manipulated to produce anatomically realistic phantoms for low-contrast detectability experiments. The phantoms and our initial experiments provide a groundwork for the assessment of CT image quality in a clinical context. Key Points • Phantoms generated from manipulated CT images provide patient anatomy and can be used for detection tasks to evaluate the diagnostic performance of CT images. • Radiologists are unconfident and unreliable in detecting hypodense lesions of 20 HU contrast and less in an anatomical neck background. • Detectability experiments with anatomically realistic phantoms can assess CT image quality in a clinical context.

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Effects of automatic tube potential selection on radiation dose index, image quality, and lesion detectability in pediatric abdominopelvic CT and CTA: a phantom study

Abstract: ATPS automatically individualizes CT scan technique for each patient. ATPS lowers radiation dose in routine pitch pediatric abdominopelvic CT and CTA. There is no loss of image quality or lesion detectability with ATPS. Pitch and scan range impact the effectiveness of ATPS dose reduction.

Cited by 10 publications

References 30 publications

Radiation Dose Reduction at Pediatric CT: Use of Low Tube Voltage and Iterative Reconstruction

Radiation Dose Reduction at Pediatric CT: Use of Low Tube Voltage and Iterative Reconstruction

Task-based assessment of neck CT protocols using patient-mimicking phantoms—effects of protocol parameters on dose and diagnostic performance

3D printing of anatomically realistic phantoms with detection tasks to assess the diagnostic performance of CT images

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