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Chen LG, Kao HW, Wu PA, Sheu MH, Huang LC. Optimal image quality and radiation doses with optimal tube voltages/currents for pediatric anthropomorphic phantom brains. PLoS One 2024; 19:e0306857. [PMID: 39037987 PMCID: PMC11262643 DOI: 10.1371/journal.pone.0306857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 06/25/2024] [Indexed: 07/24/2024] Open
Abstract
OBJECTIVE Using pediatric anthropomorphic phantoms (APs), we aimed to determine the scanning tube voltage/current combinations that could achieve optimal image quality and avoid excessive radiation exposure in pediatric patients. MATERIALS AND METHODS A 64-slice scanner was used to scan a standard test phantom to determine the volume CT dose indices (CTDIvol), and three pediatric anthropomorphic phantoms (APs) with highly accurate anatomy and tissue-equivalent materials were studied. These specialized APs represented the average 1-year-old, 5-year-old, and 10-year-old children, respectively. The physical phantoms were constructed with brain tissue-equivalent materials having a density of ρ = 1.07 g/cm3, comprising 22 numbered 2.54-cm-thick sections for the 1-year-old, 26 sections for the 5-year-old, and 32 sections for the 10-year-old. They were scanned to acquire brain CT images and determine the standard deviations (SDs), effective doses (EDs), and contrast-to noise ratios (CNRs). The APs were scanned by 21 combinations of tube voltages/currents (80, 100, or 120 kVp/10, 40, 80, 120, 150, 200, or 250 mA) and rotation time/pitch settings of 1 s/0.984:1. RESULTS The optimal tube voltage/current combinations yielding optimal image quality were 80 kVp/80 mA for the 1-year-old AP; 80 kVp/120 mA for the 5-year-old AP; and 80 kVp/150 mA for the 10-year-old AP. Because these scanning tube voltages/currents yielded SDs, respectively, of 12.81, 13.09, and 12.26 HU, along with small EDs of 0.31, 0.34, and 0.31 mSv, these parameters and the induced values were expediently defined as optimal. CONCLUSIONS The optimal tube voltages/currents that yielded optimal brain image quality, SDs, CNRs, and EDs herein are novel and essentially important. Clinical translation of these optimal values may allow CT diagnosis with low radiation doses to children's heads.
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Affiliation(s)
- Li-Guo Chen
- Department of Medical Imaging, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
| | - Hung-Wen Kao
- Department of Medical Imaging, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
- Department of Radiology, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Ping-An Wu
- Department of Medical Imaging, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
| | - Ming-Huei Sheu
- Department of Medical Imaging, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
| | - Li-Chuan Huang
- Department of Medical Imaging, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
- Department of Medical Imaging and Radiological Sciences, Tzu Chi University of Science and Technology, Hualien, Taiwan
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Priyanka, Kadavigere R, Sukumar S. Low Dose Pediatric CT Head Protocol using Iterative Reconstruction Techniques: A Comparison with Standard Dose Protocol. Clin Neuroradiol 2024; 34:229-239. [PMID: 38015280 DOI: 10.1007/s00062-023-01361-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 10/11/2023] [Indexed: 11/29/2023]
Abstract
PURPOSE Pediatric computed tomography (CT) head examination has also increased in recent years with the advancement in CT technology; however, children exposed to radiation at the youngest age are more vulnerable to the risks of radiation. The aim of the study is to evaluate radiation dose and image quality of low dose pediatric CT head protocol compared to standard dose pediatric CT head protocol. METHODS This was a prospective study. Group 1 included 73 patients aged < 1 year and 70 patients in the 1-5 years age group and had undergone CT head examination using the standard dose protocol. Group 2 included 31 patients aged < 1 year and 40 patients in the 1-5 years age group and had undergone CT head examination using the low dose protocol. The radiation dose was measured and image quality was assessed quantitatively and qualitatively. RESULTS There was a significant difference in radiation dose between the standard and low dose protocols (p > 0.05) with lower radiation dose for low dose group. The qualitative analysis did not show a significant difference between the standard and low dose protocols. The gray-white matter differentiation (GWMD), attenuation, contrast to noise ratio (CNR) and figure of merit (FOM) were higher in the low dose protocol compared to the standard dose with a significant difference (p > 0.05). CONCLUSION The study concludes that a low dose protocol at 80 kV tube voltage/150 mAs tube current exposure time product/iterative reconstruction-iDose4 (level 3) for < 1 year age group and 100 kV/200m As/iDose4 (level 3) for 1-5 years age group provides ultra-low effective dose with diagnostically acceptable image quality for pediatric CT head examination compared with standard dose protocol.
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Affiliation(s)
- Priyanka
- Department of Medical Imaging Technology, Manipal College of Health Professions, Manipal Academy of Higher Education, Manipal, Karnataka, India, 576104
| | - Rajagopal Kadavigere
- Department of Radio diagnosis and Imaging, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, Karnataka, India, 576104.
| | - Suresh Sukumar
- Department of Medical Imaging Technology, Manipal College of Health Professions, Manipal Academy of Higher Education, Manipal, Karnataka, India, 576104
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Lyoo Y, Choi YH, Lee SB, Lee S, Cho YJ, Shin SM, Phi JH, Kim SK, Cheon JE. Ultra-low-dose computed tomography with deep learning reconstruction for craniosynostosis at radiation doses comparable to skull radiographs: a pilot study. Pediatr Radiol 2023; 53:2260-2268. [PMID: 37488451 DOI: 10.1007/s00247-023-05717-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 06/28/2023] [Accepted: 06/29/2023] [Indexed: 07/26/2023]
Abstract
BACKGROUND Craniofacial computed tomography (CT) is the diagnostic investigation of choice for craniosynostosis, but high radiation dose remains a concern. OBJECTIVE To evaluate the image quality and diagnostic performance of an ultra-low-dose craniofacial CT protocol with deep learning reconstruction for diagnosis of craniosynostosis. MATERIALS AND METHODS All children who underwent initial craniofacial CT for suspected craniosynostosis between September 2021 and September 2022 were included in the study. The ultra-low-dose craniofacial CT protocol using 70 kVp, model-based iterative reconstruction and deep learning reconstruction techniques was compared with a routine-dose craniofacial CT protocol. Quantitative analysis of the signal-to-noise ratio and noise was performed. The 3-dimensional (D) volume-rendered images were independently evaluated by two radiologists with regard to surface coarseness, step-off artifacts and overall image quality on a 5-point scale. Sutural patency was assessed for each of six sutures. Radiation dose was compared between the two protocols. RESULTS Among 29 patients (15 routine-dose CT and 14 ultra-low-dose CT), 23 patients had craniosynostosis. The 3-D volume-rendered images of ultra-low-dose CT without deep learning showed decreased image quality compared to routine-dose CT. The 3-D volume-rendered images of ultra-low-dose CT with deep learning reconstruction showed higher noise level, higher surface coarseness but decreased step-off artifacts, comparable signal-to-noise ratio and overall similar image quality compared to the routine-dose CT images. Diagnostic performance for detecting craniosynostosis at the suture level showed no significant difference between ultra-low-dose CT without deep learning reconstruction, ultra-low-dose CT with deep learning reconstruction and routine-dose CT. The estimated effective radiation dose for the ultra-low-dose CT was 0.05 mSv (range, 0.03-0.06 mSv), a 95% reduction in dose over the routine-dose CT at 1.15 mSv (range, 0.54-1.74 mSv). This radiation dose is comparable to 4-view skull radiography (0.05-0.1 mSv) and lower than previously reported effective dose for craniosynostosis protocols (0.08-3.36 mSv). CONCLUSION In this pilot study, an ultra-low-dose CT protocol using radiation doses at a level similar to skull radiographs showed preserved diagnostic performance for craniosynostosis, but decreased image quality compared to the routine-dose CT protocol. However, by combining the ultra-low-dose CT protocol with deep learning reconstruction, image quality was improved to a level comparable to the routine-dose CT protocol, without sacrificing diagnostic performance for craniosynostosis.
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Affiliation(s)
- Youngwook Lyoo
- Department of Radiology, Seoul National University Hospital, 101 Daehak-Ro, Jongno-Gu, Seoul, 03080, Republic of Korea
- Department of Radiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Young Hun Choi
- Department of Radiology, Seoul National University Hospital, 101 Daehak-Ro, Jongno-Gu, Seoul, 03080, Republic of Korea.
- Department of Radiology, Seoul National University College of Medicine, Seoul, Republic of Korea.
| | - Seul Bi Lee
- Department of Radiology, Seoul National University Hospital, 101 Daehak-Ro, Jongno-Gu, Seoul, 03080, Republic of Korea
- Department of Radiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Seunghyun Lee
- Department of Radiology, Seoul National University Hospital, 101 Daehak-Ro, Jongno-Gu, Seoul, 03080, Republic of Korea
- Department of Radiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Yeon Jin Cho
- Department of Radiology, Seoul National University Hospital, 101 Daehak-Ro, Jongno-Gu, Seoul, 03080, Republic of Korea
| | - Su-Mi Shin
- Department of Radiology, SMG-SNU Boramae Medical Center, Seoul, Republic of Korea
| | - Ji Hoon Phi
- Department of Pediatric Neurosurgery, Seoul National University Hospital, Seoul, Republic of Korea
| | - Seung Ki Kim
- Department of Pediatric Neurosurgery, Seoul National University Hospital, Seoul, Republic of Korea
| | - Jung-Eun Cheon
- Department of Radiology, Seoul National University Hospital, 101 Daehak-Ro, Jongno-Gu, Seoul, 03080, Republic of Korea
- Department of Radiology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea
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Tan Z, Zhang L, Sun X, Yang M, Makamure J, Wu H, Wang J. Dual-Layer Detector Head CT to Maintain Image Quality While Reducing the Radiation Dose in Pediatric Patients. AJNR Am J Neuroradiol 2023; 44:1212-1218. [PMID: 37735089 PMCID: PMC10549953 DOI: 10.3174/ajnr.a7999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 08/02/2023] [Indexed: 09/23/2023]
Abstract
BACKGROUND AND PURPOSE Radiation exposure in the CT diagnostic imaging process is a conspicuous concern in pediatric patients. This study aimed to evaluate whether 60-keV virtual monoenergetic images of the pediatric cranium in dual-layer CT can reduce the radiation dose while maintaining image quality compared with conventional images. MATERIALS AND METHODS One hundred six unenhanced pediatric head scans acquired by dual-layer CT were retrospectively assessed. The patients were assigned to 2 groups of 53 and scanned with 250 and 180 mAs, respectively. Dose-length product values were retrieved, and noise, SNR, and contrast-to-noise ratio were calculated for each case. Two radiologists blinded to the reconstruction technique used evaluated image quality on a 5-point Likert scale. Statistical assessment was performed with ANOVA and the Wilcoxon test, adjusted for multiple comparisons. RESULTS Mean dose-length product values were 717.47 (SD, 41.52) mGy×cm and 520.74 (SD, 42) mGy×cm for the 250- and 180-mAs groups, respectively. Irrespective of the radiation dose, noise was significantly lower, SNR and contrast-to-noise ratio were significantly higher, and subjective analysis revealed significant superiority of 60-keV virtual monoenergetic images compared with conventional images (all P < .001). SNR, contrast-to-noise ratio, and subjective evaluation in 60-keV virtual monoenergetic images were not significantly different between the 2 scan groups (P > .05). Radiation dose parameters were significantly lower in the 180-mAs group compared with the 250-mAs group (P < .001). CONCLUSIONS Dual-layer CT 60-keV virtual monoenergetic images allowed a radiation dose reduction of 28% without image-quality loss in pediatric cranial CT.
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Affiliation(s)
- Zhengwu Tan
- From the Department of Radiology (Z.T., L.Z., X.S., M.Y., J.M., H.W., J.W.), Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Hubei Province Key Laboratory of Molecular Imaging (Z.T., L.Z., X.S., M.Y., J.M., H.W., J.W.), Wuhan, Hubei, China
| | - Lan Zhang
- From the Department of Radiology (Z.T., L.Z., X.S., M.Y., J.M., H.W., J.W.), Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Hubei Province Key Laboratory of Molecular Imaging (Z.T., L.Z., X.S., M.Y., J.M., H.W., J.W.), Wuhan, Hubei, China
| | - Xiaojie Sun
- From the Department of Radiology (Z.T., L.Z., X.S., M.Y., J.M., H.W., J.W.), Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Hubei Province Key Laboratory of Molecular Imaging (Z.T., L.Z., X.S., M.Y., J.M., H.W., J.W.), Wuhan, Hubei, China
| | - Ming Yang
- From the Department of Radiology (Z.T., L.Z., X.S., M.Y., J.M., H.W., J.W.), Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Hubei Province Key Laboratory of Molecular Imaging (Z.T., L.Z., X.S., M.Y., J.M., H.W., J.W.), Wuhan, Hubei, China
| | - Joyman Makamure
- From the Department of Radiology (Z.T., L.Z., X.S., M.Y., J.M., H.W., J.W.), Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Hubei Province Key Laboratory of Molecular Imaging (Z.T., L.Z., X.S., M.Y., J.M., H.W., J.W.), Wuhan, Hubei, China
| | - Hongying Wu
- From the Department of Radiology (Z.T., L.Z., X.S., M.Y., J.M., H.W., J.W.), Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Hubei Province Key Laboratory of Molecular Imaging (Z.T., L.Z., X.S., M.Y., J.M., H.W., J.W.), Wuhan, Hubei, China
| | - Jing Wang
- From the Department of Radiology (Z.T., L.Z., X.S., M.Y., J.M., H.W., J.W.), Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Hubei Province Key Laboratory of Molecular Imaging (Z.T., L.Z., X.S., M.Y., J.M., H.W., J.W.), Wuhan, Hubei, China
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Tan Z, Zhang L, Sun X, Yang M, Wu H, Wang J. Dual-layer spectral CT improves the image quality of cerebral unenhanced CT scan in children. Eur J Radiol 2023; 164:110879. [PMID: 37182416 DOI: 10.1016/j.ejrad.2023.110879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 04/25/2023] [Accepted: 05/05/2023] [Indexed: 05/16/2023]
Abstract
PURPOSE To evaluate the image quality and determine the optimal energies of virtual monoenergetic imaging (VMI) in unenhanced pediatric cerebral scans by dual-layer spectral detector computed tomography (DLCT). METHODS Fifty-three consecutive unenhanced cerebral scans by a DLCT scanner in children (age ≤ 12 years) were retrospectively analyzed. Conventional images (CI) and VMIs were reconstructed. The gray matter (GM) and white matter (WM) noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), posterior fossa, and subcalvarial artifac tindex (PFAI, SAI) were calculated. Two radiologists independently determined the image quality using a 5-point Likert-type scale based on GM - WM differentiation (GWMA), subcalvarialspace (SAA), beam hardening artifacts in the posterior fossa (PFAA), and the overall diagnostic quality. The student t-test and Wilcoxon test were used to determining the statistical significance. RESULTS Compared with CI, superior noise were observed in VMI at low keV levels and were lowest at 100 keV (P < 0.001); the SNR and CNR were significantly higher at the 45 keV to 75 keV levels (all Ps of <0.005). The best GWMA were noticed at the 50 keV level compared to other keV levels (all P < 0.05). The optimal SAA and PFAA were found at 100 keV, respectively. The assessment of overall diagnostic quality was the best at 50 keV (P < 0.013 to < 0.001). CONCLUSIONS The VMI scan significantly improved the quality of pediatric cerebral images compared with those from CI. The optimal energy level for the brainparenchyma was 50 keV while those for subcalvarial space and posterior fossa were 100 keV.
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Affiliation(s)
- Zhengwu Tan
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Hubei Province Key Laboratory of Molecular Imaging, Wuhan, Hubei, China.
| | - Lan Zhang
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Hubei Province Key Laboratory of Molecular Imaging, Wuhan, Hubei, China.
| | - Xiaojie Sun
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Hubei Province Key Laboratory of Molecular Imaging, Wuhan, Hubei, China.
| | - Ming Yang
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Hubei Province Key Laboratory of Molecular Imaging, Wuhan, Hubei, China.
| | - Hongying Wu
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Hubei Province Key Laboratory of Molecular Imaging, Wuhan, Hubei, China.
| | - Jing Wang
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Hubei Province Key Laboratory of Molecular Imaging, Wuhan, Hubei, China.
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Inoue Y, Itoh H, Shiibashi N, Sasa R, Mitsui K. Sample Size and Estimation of Standard Radiation Doses for Pediatric Brain CT. Tomography 2022; 8:2486-2497. [PMID: 36287806 PMCID: PMC9612354 DOI: 10.3390/tomography8050207] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 09/24/2022] [Accepted: 09/29/2022] [Indexed: 11/04/2022] Open
Abstract
Estimation of the standard radiation dose at each imaging facility is required for radiation dose management, including establishment and utilization of the diagnostic reference levels. We investigated methods to estimate the standard dose for pediatric brain computed tomography (CT) using a small number of data. From 980 pediatric brain CT examinations, 25, 50, and 100 examinations were randomly extracted to create small, medium, and large datasets, respectively. The standard dose was estimated by applying grouping and curve-fitting methods for 20 datasets of each sample size. For the grouping method, data were divided into groups according to age or body weight, and the standard dose was defined as a median value in each group. For the curve-fitting methods, logarithmic, power, and bilinear functions were fitted to plots of radiation dose against age or weight, and the standard dose was calculated at the designated age or weight using the derived equation. When the sample size was smaller, the random variations of the estimated standard dose were larger. Better estimation of the standard dose was achieved with the curve-fitting methods than with the grouping method. Power fitting appeared to be more effective than logarithmic and bilinear fittings for suppressing random variation. Determination of the standard dose for pediatric brain CT by the curve-fitting method is recommended to improve radiation dose optimization at facilities performing the imaging procedure infrequently.
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Affiliation(s)
- Yusuke Inoue
- Department of Diagnostic Radiology, Kitasato University School of Medicine, Sagamihara 252-0374, Kanagawa, Japan
| | - Hiroyasu Itoh
- Department of Radiology, Kitasato University Hospital, Sagamihara 252-0374, Kanagawa, Japan
| | - Nao Shiibashi
- Department of Diagnostic Radiology, Kitasato University School of Medicine, Sagamihara 252-0374, Kanagawa, Japan
| | - Ryosuke Sasa
- Department of Radiology, Kitasato University Hospital, Sagamihara 252-0374, Kanagawa, Japan
| | - Kohei Mitsui
- Department of Diagnostic Radiology, Kitasato University School of Medicine, Sagamihara 252-0374, Kanagawa, Japan
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Inoue Y, Itoh H, Waga A, Sasa R, Mitsui K. Radiation Dose Management in Pediatric Brain CT According to Age and Weight as Continuous Variables. Tomography 2022; 8:985-998. [PMID: 35448713 PMCID: PMC9027691 DOI: 10.3390/tomography8020079] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 03/26/2022] [Accepted: 03/31/2022] [Indexed: 12/28/2022] Open
Abstract
The diagnostic reference levels (DRLs) for pediatric brain computed tomography (CT) are provided for groups divided according to age. We investigated the relationships of radiation dose indices (volume CT dose index and dose length product) with age and weight, as continuous variables, in pediatric brain CT. In a retrospective analysis, 980 pediatric brain CT examinations were analyzed. Curve fitting was performed for plots of the CT dose indices versus age and weight, and equations to estimate age- and weight-dependent standard dose indices were derived. Standard dose indices were estimated using the equations, and the errors were calculated. The results showed a biphasic increase in dose indices with increasing age and weight, characterized by a rapid initial and subsequent slow increase. Logarithmic, power, and bilinear functions were well fitted to the plots, allowing estimation of standard dose indices at an arbitrary age or weight. Error analysis suggested that weight was mildly better than age and that the best results were obtained with the bilinear function. Curve fitting of the relationship between CT dose indices and age or weight facilitates the determination of standard dose indices in pediatric brain CT at each facility and is expected to aid the establishment and application of the DRLs.
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Affiliation(s)
- Yusuke Inoue
- Department of Diagnostic Radiology, Kitasato University School of Medicine, Sagamihara 252-0374, Japan; (A.W.); (K.M.)
| | - Hiroyasu Itoh
- Department of Radiology, Kitasato University Hospital, Sagamihara 252-0375, Japan; (H.I.); (R.S.)
| | - Anri Waga
- Department of Diagnostic Radiology, Kitasato University School of Medicine, Sagamihara 252-0374, Japan; (A.W.); (K.M.)
| | - Ryosuke Sasa
- Department of Radiology, Kitasato University Hospital, Sagamihara 252-0375, Japan; (H.I.); (R.S.)
| | - Kohei Mitsui
- Department of Diagnostic Radiology, Kitasato University School of Medicine, Sagamihara 252-0374, Japan; (A.W.); (K.M.)
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Tanoue S, Nakaura T, Nagayama Y, Uetani H, Ikeda O, Yamashita Y. Virtual Monochromatic Image Quality from Dual-Layer Dual-Energy Computed Tomography for Detecting Brain Tumors. Korean J Radiol 2021; 22:951-958. [PMID: 33569932 PMCID: PMC8154786 DOI: 10.3348/kjr.2020.0677] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 09/13/2020] [Accepted: 10/08/2020] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To evaluate the usefulness of virtual monochromatic images (VMIs) obtained using dual-layer dual-energy CT (DL-DECT) for evaluating brain tumors. MATERIALS AND METHODS This retrospective study included 32 patients with brain tumors who had undergone non-contrast head CT using DL-DECT. Among them, 15 had glioblastoma (GBM), 7 had malignant lymphoma, 5 had high-grade glioma other than GBM, 3 had low-grade glioma, and 2 had metastatic tumors. Conventional polychromatic images and VMIs (40-200 keV at 10 keV intervals) were generated. We compared CT attenuation, image noise, contrast, and contrast-to-noise ratio (CNR) between tumor and white matter (WM) or grey matter (GM) between VMIs showing the highest CNR (optimized VMI) and conventional CT images using the paired t test. Two radiologists subjectively assessed the contrast, margin, noise, artifact, and diagnostic confidence of optimized VMIs and conventional images on a 4-point scale. RESULTS The image noise of VMIs at all energy levels tested was significantly lower than that of conventional CT images (p < 0.05). The 40-keV VMIs yielded the best CNR. Furthermore, both contrast and CNR between the tumor and WM were significantly higher in the 40 keV images than in the conventional CT images (p < 0.001); however, the contrast and CNR between tumor and GM were not significantly different (p = 0.47 and p = 0.31, respectively). The subjective scores assigned to contrast, margin, and diagnostic confidence were significantly higher for 40 keV images than for conventional CT images (p < 0.01). CONCLUSION In head CT for patients with brain tumors, compared with conventional CT images, 40 keV VMIs from DL-DECT yielded superior tumor contrast and diagnostic confidence, especially for brain tumors located in the WM.
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Affiliation(s)
- Shota Tanoue
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Yasunori Nagayama
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Hiroyuki Uetani
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Osamu Ikeda
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Yasuyuki Yamashita
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
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van Ommen F, Bennink E, Dankbaar JW, Kauw F, de Jong HWAM. Improving the Quality of Cerebral Perfusion Maps With Monoenergetic Dual-Energy Computed Tomography Reconstructions. J Comput Assist Tomogr 2021; 45:103-109. [PMID: 32176156 DOI: 10.1097/rct.0000000000000981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE We compared 40- to 70-keV virtual monoenergetic to conventional computed tomography (CT) perfusion reconstructions with respect to quality of perfusion maps. METHODS Conventional CT perfusion (CTP) images were acquired at 80 kVp in 25 patients, and 40- to 70-keV images were acquired with a dual-layer CT at 120 kVp in 25 patients. First, time-attenuation-curve contrast-to-noise ratio was assessed. Second, the perfusion maps of both groups were qualitatively analyzed by observers. Last, the monoenergetic reconstruction with the highest quality was compared with the clinical standard 80-kVp CTP acquisitions. RESULTS Contrast-to-noise ratio was significantly better for 40 to 60 keV as compared with 70 keV and conventional images (P < 0.001). Visually, the difference between the blood volume maps among reconstructions was minimal. The 50-keV perfusion maps had the highest quality compared with the other monoenergetic and conventional maps (P < 0.002). CONCLUSIONS The quality of 50-keV CTP images is superior to the quality of conventional 80- and 120-kVp images.
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Affiliation(s)
| | | | | | - Frans Kauw
- From the Departments of Radiology and Nuclear Medicine
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Muhammad NA, Abdul Karim MK, Abu Hassan H, Ahmad Kamarudin M, Ding Wong JH, Ng KH. Diagnostic Reference Level of Radiation Dose and Image Quality among Paediatric CT Examinations in A Tertiary Hospital in Malaysia. Diagnostics (Basel) 2020; 10:E591. [PMID: 32823818 PMCID: PMC7460376 DOI: 10.3390/diagnostics10080591] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/22/2020] [Accepted: 07/22/2020] [Indexed: 01/27/2023] Open
Abstract
Pediatrics are more vulnerable to radiation and are prone to dose compared to adults, requiring more attention to computed tomography (CT) optimization. Hence, diagnostic reference levels (DRLs) have been implemented as part of optimization process in order to monitor CT dose and diagnostic quality. The noise index has recently been endorsed to be included as a part of CT optimization in the DRLs report. In this study, we have therefore set local DRLs for pediatric CT examination with a noise index as an indicator of image quality. One thousand one hundred and ninety-two (1192) paediatric patients undergoing CT brain, CT thorax and CT chest-abdomen-pelvis (CAP) examinations were analyzed retrospectively and categorized into four age groups; group 1 (0-1 year), group 2 (1-5 years), group 3 (5-10 years) and group 4 (10-15 years). For each group, data such as the volume-weighted CT dose index (CTDIvol), dose-length product (DLP) and the effective dose (E) were calculated and DRLs for each age group set at 50th percentile were determined. Both CT dose and image noise values between age groups have differed significantly with p-value < 0.05. The highest CTDIvol and DLP values in all age groups with the lowest noise index value reported in the 10-15 age group were found in CT brain examination. In conclusion, there was a significant variation in doses and noise intensity among children of different ages, and the need to change specific parameters to fit the clinical requirement.
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Affiliation(s)
- Nor Azura Muhammad
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (N.A.M.); (M.A.K.)
| | - Muhammad Khalis Abdul Karim
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (N.A.M.); (M.A.K.)
- Centre of Diagnostic Nuclear Imaging, Faculty of Medicine, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
| | - Hasyma Abu Hassan
- Department of Imaging, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia;
| | - Mazliana Ahmad Kamarudin
- Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (N.A.M.); (M.A.K.)
| | - Jeannie Hsiu Ding Wong
- Department of Biomedical Imaging, University Malaya Medical Centre, Petaling Jaya 59100, Kuala Lumpur, Malaysia; (J.H.D.W.); (K.H.N.)
| | - Kwan Hoong Ng
- Department of Biomedical Imaging, University Malaya Medical Centre, Petaling Jaya 59100, Kuala Lumpur, Malaysia; (J.H.D.W.); (K.H.N.)
- Department of Medical Imaging and Radiological Sciences, College of Health Sciences, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
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11
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van Ommen F, Dankbaar JW, Zhu G, Wolman DN, Heit JJ, Kauw F, Bennink E, de Jong HWAM, Wintermark M. Virtual monochromatic dual-energy CT reconstructions improve detection of cerebral infarct in patients with suspicion of stroke. Neuroradiology 2020; 63:41-49. [PMID: 32728777 PMCID: PMC7803871 DOI: 10.1007/s00234-020-02492-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 07/05/2020] [Indexed: 12/12/2022]
Abstract
Purpose Early infarcts are hard to diagnose on non-contrast head CT. Dual-energy CT (DECT) may potentially increase infarct differentiation. The optimal DECT settings for differentiation were identified and evaluated. Methods One hundred and twenty-five consecutive patients who presented with suspected acute ischemic stroke (AIS) and underwent non-contrast DECT and subsequent DWI were retrospectively identified. The DWI was used as reference standard. First, virtual monochromatic images (VMI) of 25 patients were reconstructed from 40 to 140 keV and scored by two readers for acute infarct. Sensitivity, specificity, positive, and negative predictive values for infarct detection were compared and a subset of VMI energies were selected. Next, for a separate larger cohort of 100 suspected AIS patients, conventional non-contrast CT (NCT) and selected VMI were scored by two readers for the presence and location of infarct. The same statistics for infarct detection were calculated. Infarct location match was compared per vascular territory. Subgroup analyses were dichotomized by time from last-seen-well to CT imaging. Results A total of 80–90 keV VMI were marginally more sensitive (36.3–37.3%) than NCT (32.4%; p > 0.680), with marginally higher specificity (92.2–94.4 vs 91.1%; p > 0.509) for infarct detection. Location match was superior for VMI compared with NCT (28.7–27.4 vs 19.5%; p < 0.010). Within 4.5 h from last-seen-well, 80 keV VMI more accurately detected infarct (58.0 vs 54.0%) and localized infarcts (27.1 vs 11.9%; p = 0.004) than NCT, whereas after 4.5 h, 90 keV VMI was more accurate (69.3 vs 66.3%). Conclusion Non-contrast 80–90 keV VMI best differentiates normal from infarcted brain parenchyma. Electronic supplementary material The online version of this article (10.1007/s00234-020-02492-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Fasco van Ommen
- Department of Neuroradiology, Stanford University Medical Center, Palo Alto, CA USA
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, E01.132, P.O. Box 85500, 3508 GA Utrecht, the Netherlands
| | - Jan Willem Dankbaar
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, E01.132, P.O. Box 85500, 3508 GA Utrecht, the Netherlands
| | - Guangming Zhu
- Department of Neuroradiology, Stanford University Medical Center, Palo Alto, CA USA
| | - Dylan N. Wolman
- Department of Neuroradiology, Stanford University Medical Center, Palo Alto, CA USA
| | - Jeremy J. Heit
- Department of Neuroradiology, Stanford University Medical Center, Palo Alto, CA USA
| | - Frans Kauw
- Department of Neuroradiology, Stanford University Medical Center, Palo Alto, CA USA
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, E01.132, P.O. Box 85500, 3508 GA Utrecht, the Netherlands
| | - Edwin Bennink
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, E01.132, P.O. Box 85500, 3508 GA Utrecht, the Netherlands
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Hugo W. A. M. de Jong
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, E01.132, P.O. Box 85500, 3508 GA Utrecht, the Netherlands
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Max Wintermark
- Department of Neuroradiology, Stanford University Medical Center, Palo Alto, CA USA
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12
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Kharita MH, Al-Naemi H, Arru C, Omar AJ, Aly A, Tsalafoutas I, Alkhazzam S, Singh R, Kalra MK. Relation between age and CT radiation doses: Dose trends in 705 pediatric head CT. Eur J Radiol 2020; 130:109138. [PMID: 32619755 DOI: 10.1016/j.ejrad.2020.109138] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 05/18/2020] [Accepted: 06/12/2020] [Indexed: 11/24/2022]
Abstract
PURPOSE To evaluate the relationship between patient age and radiation doses associated with routine pediatric head CT performed with automatic tube potential selection and tube current modulation techniques. METHODS We obtained patient demographics, scan parameters, and radiation dose descriptors (CT dose index volume -CTDIvol and dose length product -DLP) associated with consecutive routine head CT in 705 children (mean age 6.9 ± 5 years). Children were scanned on one of the three multidetector-row CTs (64-128 slices, Siemens) over 6 months period in a tertiary hospital. All head CT exams were performed in helical scan mode using automatic tube potential selection (Care kV) and automatic tube current modulation (Care Dose 4D) techniques. The information was obtained from a radiation dose monitoring software. Data were analyzed using linear correlation and analysis of variance. RESULTS Most age-wise median CTDIvol (9-27 mGy; 703/705 pediatric head CT, >99 %) from our institution were lower than the European Diagnostic Reference Levels (EDRL, CTDIvol 24-50 mGy) but median DLP (151-586 mGy cm) from 201/705 children (28 %) was higher than the EDRL (DLP 300-650 mGy cm). Unlike the age-stratified EDRL, a combination of automatic tube potential selection and tube current modulation for pediatric head results in a significant linear correlation between radiation doses and patient age (r2 = 0.66, p < 0.001). CONCLUSIONS Radiation doses for head CT change linearly with children's age. Despite lower CTDIvol and DLP for most children, longer scan length resulted in higher DLP for some pediatric head CT compared to the corresponding EDRL; this result underscores the need to promote clear guidelines for technologists operating CT.
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Affiliation(s)
| | | | - Chiara Arru
- Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
| | | | - Antar Aly
- Hamad Medical Corporation, Doha, Qatar
| | | | | | - Ramandeep Singh
- Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Mannudeep K Kalra
- Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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13
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Lee S, Choi YH, Cho YJ, Cheon JE, Choi G, Lee SB, Kim WS, Kim IO, Park JE, Pak SY. Evaluation of frequency-selective non-linear blending technique on brain CT in postoperative children with Moyamoya disease. J Neuroradiol 2019; 48:425-431. [PMID: 31539585 DOI: 10.1016/j.neurad.2019.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 07/22/2019] [Accepted: 07/25/2019] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To evaluate whether a frequency-selective non-linear blending (BC) technique can improve tissue contrast and infarct detection on non-enhanced brain CT (NECT) in postoperative Moyamoya (MMD) patients. MATERIALS AND METHODS From January 2010 to December 2017, 33 children (13boys and 20girls; mean age 9.1±3.4 years) with MMD postoperatively underwent NECT followed by diffusion MRI. We compared the contrast-to-noise ratio (CNR) between gray matter (GM) and white matter (WM) in NECT and BC images and the CNR between the infarct lesion and adjacent normal-appearing brain in NECT and BC images using a paired t-test. We assessed image noise, GM-WM differentiation, artifacts, and overall quality using a Wilcoxon signed rank test. A McNemar two-tailed test was conducted to compare the diagnostic accuracy of infarct detection. RESULTS The CNR between GM and WM and the CNR of the infarct was better in BC images than in NECT images (3.9±1.0 vs. 1.8±0.6, P<0.001 and 3.6±0.3 vs. 1.9±0.2, P<0.001), with no difference in overall image quality observed. The sensitivity and specificity of infarct detection were 55.0% and 76.9% using NECT, and 70.0% and 69.2% using BC technique. The diagnostic accuracy of NECT and BC technique was 63.6% (21/33) and 69.7% (23/33), respectively. CONCLUSION This study showed that the BC technique improved CNR and maintained image quality. This technique may also be used to identify ischemic brain changes in postoperative MMD patients by improving the CNR of the infarct lesion.
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Affiliation(s)
- Seunghyun Lee
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Young Hun Choi
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea; Department of Radiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
| | - Yeon Jin Cho
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Jung-Eun Cheon
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea; Department of Radiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Gayoung Choi
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Seul Bi Lee
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Woo Sun Kim
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea; Department of Radiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - In-One Kim
- Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea; Department of Radiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Ji Eun Park
- Department of Radiology, Ajou University Medical Center, 164 Worldcup-ro, Yeongtong-gu, Suwon, 16499, Republic of Korea
| | - Seong Yong Pak
- Department of CT research collaborations, Siemens Healthcare Ltd., 23 Chungjeong-ro, Seodaemun-gu, Seoul, South Korea
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14
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Ling LLL, Fitt G, Begbie M, Fleming CA, Perchyonok Y. Retrospective review of CT brain image quality, diagnostic adequacy and radiation dose in a paediatric population imaged at a non-paediatric tertiary hospital. J Med Imaging Radiat Oncol 2019; 63:596-601. [PMID: 31099491 DOI: 10.1111/1754-9485.12894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 04/07/2019] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Minimising radiation exposure in paediatric imaging examinations whilst maintaining acceptable diagnostic quality continues to present a challenge. The aims of this study were to assess institutional compliance of paediatric CT brain (CTB) examinations performed in an adult hospital with ARPANSA radiation dose recommendations and to compare qualitative CTB diagnostic acceptability with objective imaging parameters and radiation dose. METHODS A retrospective review of 115 consecutive paediatric CTB examinations was undertaken at an adult tertiary referral centre in Australia over a 2-year period. Dose length product (DLP) was compared with the ARPANSA standards. CTB image quality was subjectively classified by two neuroradiologists independently, with discordant results resolved by consensus. Objective assessment of image quality included measurements of signal-to-noise (SNR) and contrast-to-noise ratios (CNR) of grey and white matter. RESULTS All patient scans complied with ARPANSA DLP recommendations; however, 10 out of 115 scans were classified as being of diagnostically suboptimal image quality. These scans had significantly lower mean DLP values compared with diagnostically adequate examinations (105.1 vs 379.2 mGy.cm; P < 0.0001). CTB scans of adequate diagnostic quality, when compared to suboptimal scans, had significantly higher CNR (1.8 vs 1.1; P < 0.0001) and SNR in grey (7.1 vs 4.6; P < 0.0001) and white matter (5.6 vs 3.8; P < 0.0001). CONCLUSION All CTB examinations in this series complied with the ARPANSA DLP recommendations; however, 9% were of suboptimal diagnostic image quality. While it is important to minimize unnecessary radiation exposure, our results suggest that excessively low DLP values can lead to suboptimal diagnostic image quality.
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Affiliation(s)
- Lisa Luo-Lan Ling
- Department of Radiology, Austin Health, Heidelberg, Victoria, Australia
| | - Greg Fitt
- Department of Radiology, Austin Health, Heidelberg, Victoria, Australia
| | - Mark Begbie
- Department of Radiology, Austin Health, Heidelberg, Victoria, Australia
| | | | - Yuliya Perchyonok
- Department of Radiology, Austin Health, Heidelberg, Victoria, Australia
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15
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Dual energy head CT to maintain image quality while reducing dose in pediatric patients. Clin Imaging 2019; 55:83-88. [DOI: 10.1016/j.clinimag.2019.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 02/05/2019] [Accepted: 02/06/2019] [Indexed: 11/17/2022]
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16
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Lu H, Wang W, Li B, Sun S, Zhang H. A survey of pediatric CT doses in the Shanghai metropolitan area. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2019; 39:193-207. [PMID: 30560805 DOI: 10.1088/1361-6498/aaf923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The purpose of this study was to evaluate computed tomography (CT) doses in child examinees at different ages throughout the Shanghai metropolitan area. The head and body CT dose indices (CTDIs) of 50 CT scanners were tested by phantom measurements using standard imaging protocols. The values of CTDIw, CTDIvol and dose length product (DLP) were calculated and saved in a table along with the parameters of routine head and chest scans for different age groups of children and adults. The effective doses were estimated from the K-factors by age and DLP. The CTDIvol, DLP and effective dose for multi-detector row CT (MDCT) in children during routine head scans were larger than those for single-detector row CT (SDCT) and dual-detector row CT (DDCT). The CTDIvol, DLP and effective dose for MDCT and DDCT in children during routine chest scans were lower than those for SDCT. Radiation risks are higher for children in CT examinations compared to adults.
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Affiliation(s)
- Heqing Lu
- Department of Medical Equipment, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai 201204, People's Republic of China
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17
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Nagayama Y, Oda S, Nakaura T, Tsuji A, Urata J, Furusawa M, Utsunomiya D, Funama Y, Kidoh M, Yamashita Y. Radiation Dose Reduction at Pediatric CT: Use of Low Tube Voltage and Iterative Reconstruction. Radiographics 2018; 38:1421-1440. [DOI: 10.1148/rg.2018180041] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Yasunori Nagayama
- From the Department of Diagnostic Radiology, Graduate School of Medical Sciences (Y.N., S.O., T.N., D.U., M.K., Y.Y.), and Department of Medical Physics, Faculty of Life Sciences (Y.F.), Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; and Department of Radiology, Kumamoto City Hospital, Kumamoto, Japan (Y.N., A.T., J.U., M.F.)
| | - Seitaro Oda
- From the Department of Diagnostic Radiology, Graduate School of Medical Sciences (Y.N., S.O., T.N., D.U., M.K., Y.Y.), and Department of Medical Physics, Faculty of Life Sciences (Y.F.), Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; and Department of Radiology, Kumamoto City Hospital, Kumamoto, Japan (Y.N., A.T., J.U., M.F.)
| | - Takeshi Nakaura
- From the Department of Diagnostic Radiology, Graduate School of Medical Sciences (Y.N., S.O., T.N., D.U., M.K., Y.Y.), and Department of Medical Physics, Faculty of Life Sciences (Y.F.), Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; and Department of Radiology, Kumamoto City Hospital, Kumamoto, Japan (Y.N., A.T., J.U., M.F.)
| | - Akinori Tsuji
- From the Department of Diagnostic Radiology, Graduate School of Medical Sciences (Y.N., S.O., T.N., D.U., M.K., Y.Y.), and Department of Medical Physics, Faculty of Life Sciences (Y.F.), Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; and Department of Radiology, Kumamoto City Hospital, Kumamoto, Japan (Y.N., A.T., J.U., M.F.)
| | - Joji Urata
- From the Department of Diagnostic Radiology, Graduate School of Medical Sciences (Y.N., S.O., T.N., D.U., M.K., Y.Y.), and Department of Medical Physics, Faculty of Life Sciences (Y.F.), Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; and Department of Radiology, Kumamoto City Hospital, Kumamoto, Japan (Y.N., A.T., J.U., M.F.)
| | - Mitsuhiro Furusawa
- From the Department of Diagnostic Radiology, Graduate School of Medical Sciences (Y.N., S.O., T.N., D.U., M.K., Y.Y.), and Department of Medical Physics, Faculty of Life Sciences (Y.F.), Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; and Department of Radiology, Kumamoto City Hospital, Kumamoto, Japan (Y.N., A.T., J.U., M.F.)
| | - Daisuke Utsunomiya
- From the Department of Diagnostic Radiology, Graduate School of Medical Sciences (Y.N., S.O., T.N., D.U., M.K., Y.Y.), and Department of Medical Physics, Faculty of Life Sciences (Y.F.), Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; and Department of Radiology, Kumamoto City Hospital, Kumamoto, Japan (Y.N., A.T., J.U., M.F.)
| | - Yoshinori Funama
- From the Department of Diagnostic Radiology, Graduate School of Medical Sciences (Y.N., S.O., T.N., D.U., M.K., Y.Y.), and Department of Medical Physics, Faculty of Life Sciences (Y.F.), Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; and Department of Radiology, Kumamoto City Hospital, Kumamoto, Japan (Y.N., A.T., J.U., M.F.)
| | - Masafumi Kidoh
- From the Department of Diagnostic Radiology, Graduate School of Medical Sciences (Y.N., S.O., T.N., D.U., M.K., Y.Y.), and Department of Medical Physics, Faculty of Life Sciences (Y.F.), Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; and Department of Radiology, Kumamoto City Hospital, Kumamoto, Japan (Y.N., A.T., J.U., M.F.)
| | - Yasuyuki Yamashita
- From the Department of Diagnostic Radiology, Graduate School of Medical Sciences (Y.N., S.O., T.N., D.U., M.K., Y.Y.), and Department of Medical Physics, Faculty of Life Sciences (Y.F.), Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; and Department of Radiology, Kumamoto City Hospital, Kumamoto, Japan (Y.N., A.T., J.U., M.F.)
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Takada K, Ichikawa K, Banno S, Otobe K. [Suggestion of the Relative Artifact Index for Noise-independent Evaluation of the Streak Artifact]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2018; 74:315-325. [PMID: 29681598 DOI: 10.6009/jjrt.2018_jsrt_74.4.315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The aim of this study was to inspect the usefulness of relative artifact index (AIr), which divided artifact index (AI) by standard deviation of the noise image for noise-independent evaluation of the streak artifact in computed tomography images. A water phantom without/with a cylindrical phantom filled with diluted contrast medium was scanned with different tube voltages (100/120/140 kV) and radiation doses (5/10/20 mGy), then images were reconstructed with different kernels (B10/30/50f). AI, location parameter in Gumbel method and AIr were measured in each condition and compared. The higher tube voltage or radiation dose or lower spatial resolution kernel, the lower quantitative values were presented by both AI and Gumbel method. AIr showed quantitative values independent of radiation dose and kernel, and substantial artifact amounts affected only by tube voltage. Our results showed AIr can evaluate quantitative artifact amount independent of image noise.
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Affiliation(s)
- Ken Takada
- Department of Medical Technology, Ogaki Municipal Hospital
| | - Katsuhiro Ichikawa
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
| | - Shinnya Banno
- Department of Medical Technology, Ogaki Municipal Hospital
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Advanced virtual monochromatic reconstruction of dual-energy unenhanced brain computed tomography in children: comparison of image quality against standard mono-energetic images and conventional polychromatic computed tomography. Pediatr Radiol 2017; 47:1648-1658. [PMID: 28656326 DOI: 10.1007/s00247-017-3908-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 04/01/2017] [Accepted: 05/19/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND Advanced virtual monochromatic reconstruction from dual-energy brain CT has not been evaluated in children. OBJECTIVE To determine the most effective advanced virtual monochromatic imaging energy level for maximizing pediatric brain parenchymal image quality in dual-energy unenhanced brain CT and to compare this technique with conventional monochromatic reconstruction and polychromatic scanning. MATERIALS AND METHODS Using both conventional (Mono) and advanced monochromatic reconstruction (Mono+) techniques, we retrospectively reconstructed 13 virtual monochromatic imaging energy levels from 40 keV to 100 keV in 5-keV increments from dual-source, dual-energy unenhanced brain CT scans obtained in 23 children. We analyzed gray and white matter noise ratios, signal-to-noise ratios and contrast-to-noise ratio, and posterior fossa artifact. We chose the optimal mono-energetic levels and compared them with conventional CT. RESULTS For Mono+maximum optima were observed at 60 keV, and minimum posterior fossa artifact at 70 keV. For Mono, optima were at 65-70 keV, with minimum posterior fossa artifact at 75 keV. Mono+ was superior to Mono and to polychromatic CT for image-quality measures. Subjective analysis rated Mono+superior to other image sets. CONCLUSION Optimal virtual monochromatic imaging using Mono+ algorithm demonstrated better image quality for gray-white matter differentiation and reduction of the artifact in the posterior fossa.
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