1
|
Açıkgöz G. Investigating the Effects of Tube Current and Tube Voltage on Patient Dose in Computed Tomography Examinations with Principial Component Analysis and Cluster Analysis: Phantom Study. HEALTH PHYSICS 2024:00004032-990000000-00150. [PMID: 38787573 DOI: 10.1097/hp.0000000000001830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
ABSTRACT The aim of this study was to investigate the effects of tube current and tube voltage choices on patient dose in adult and pediatric CT protocols by qualitative analysis using Principal Component Analysis (PCA), cluster analysis, and statistical analysis.Dose length product (DLP), Effective mAs (Eff. mAs), and volume-weighted CT dose index (CTDIvol) dose descriptors were obtained from 16 adult and pediatric head phantom CT examinations. Different tube voltage and tube current values were selected in both pediatric head and adult head CT imaging protocols, and PCA and cluster analysis were applied to the data obtained for qualitative analysis of the relationship between CTDIvol, Eff. mAs and Total DLP values. The two principial components (PC) with the highest values among those obtained as a result of the PCA method were used. PC1 was 70.97%, and PC2 was 28.03%. In the cluster analysis, it was observed that the values obtained from pediatric and adult phantom CT scans were classified into two different clusters. The correlation coefficient for adult patients was r = 0.998, and for pediatric patients, the correlation coefficient was r = 0.947. When the obtained clusters were examined, the degree of closeness or distance of the variables could be observed. In the study, as a result of the analysis of CTDIvol, Eff. mAs and Total DLP data based on manufacturer data at different kV and mA values with PCA and cluster analysis, it was shown that pediatric patients could be exposed to more radiation than the adult patients.
Collapse
Affiliation(s)
- Güneş Açıkgöz
- Hatay Mustafa Kemal University Vocational School of Health Services, Hatay/Turkey. Güneş Açıkgöz, Hatay MKÜ: Hatay Mustafa Kemal Universitesi, Serinyol HMKU campus, Hatay 31100 (ORCID: 0000-0001-9118-3153)
| |
Collapse
|
2
|
Girsa D, Kremenova K, Lukavsky J, Sukupova L, Malikova H. Comparison of dose length product and image quality of a biphasic whole-body polytrauma CT protocol with and without the automatic tube voltage selection. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2024. [PMID: 38445394 DOI: 10.5507/bp.2024.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024] Open
Abstract
BACKGROUND AND AIMS A significant source of man-made radiation is now linked to medical devices especially X-ray imaging based ones like CT scans which expose the body to cumulative ionizing radiation and thus attendant cancer risks. The aim of this study was to determine whether using a combination of Automatic Tube Current Modulation (ATCM) and Automatic Tube Voltage Selection (ATVS) during two-phase whole-body CT (2PWBCT) examinations would reduce the radiation dose while preserving the image quality. PATIENTS AND METHODS This was a prospective, observational, single-centre study of 127 adult patients who had undergone the 2PWBCT polytraumatic protocol. All were examined on a Somatom Drive scanner (Siemens). The patients were divided into two groups: ATCM only (42 patients) and ATCM +ATVS (85 patients). Patients' arm positions during examination and the examination dose length product (DLP) values were recorded, as well the standard deviations (SD) of the density in reference areas on CT scans for the image quality assessment. The DLP values and image quality in the groups were compared using ANOVA. RESULTS Mean Total DLP (in mGy*cm): ATCM only: 3337 +/-797, ATCM+ATVS: 3402 +/-830; P=0.674. No effect of arm position (P=0.586). Mean density SD values in reference areas (in HU) in ATCM only: 49 +/-45, 15 +/-6, 9 +/-2, 12 +/-4, 10 +/-3, in ATCM+ATVS: 48 +/-45, 17 +/-6, 11 +/-3, 15 +/-6, 12 +/-4. SD values was higher in ATCM+ATVS group (P<0.001). CONCLUSION Combination of ATVS and ATCM in polytraumatic 2PWBCT leads to no significant radiation load reduction compared with ATCM only but does lead to a slight degradation of image quality. The radiation load is significantly reduced if the patient has their arms behind the head when scanning, regardless of the activation of ATVS.
Collapse
Affiliation(s)
- David Girsa
- Department of Radiology and Nuclear Medicine, Third Faculty of Medicine, Charles University in Prague and Faculty Hospital Kralovske Vinohrady; Second Faculty of Medicine, Charles University in Prague, Czech Republic
| | - Karin Kremenova
- Department of Radiology and Nuclear Medicine, Third Faculty of Medicine, Charles University in Prague and Faculty Hospital Kralovske Vinohrady, Prague, Czech Republic
| | - Jiri Lukavsky
- Institute of Psychology, Czech Academy of Sciences, 110 00 Prague, Czech Republic; Department of Psychology, Faculty of Arts, Charles University in Prague, Czech Republic
| | - Lucie Sukupova
- Director's Department, Institute for Clinical and Experimental Medicine, Prague, Czech Republic
| | - Hana Malikova
- Department of Radiology and Nuclear Medicine, Third Faculty of Medicine, Charles University in Prague and Faculty Hospital Kralovske Vinohrady; Second Faculty of Medicine, Charles University in Prague, Czech Republic
| |
Collapse
|
3
|
Kawashima H, Ichikawa K, Ueta H, Takata T, Mitsui W, Nagata H. Virtual monochromatic images of dual-energy CT as an alternative to single-energy CT: performance comparison using a detectability index for different acquisition techniques. Eur Radiol 2023; 33:5752-5760. [PMID: 36892640 DOI: 10.1007/s00330-023-09491-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 11/24/2022] [Accepted: 01/27/2023] [Indexed: 03/10/2023]
Abstract
OBJECTIVES To investigate the performance of virtual monochromatic (VM) images with the same dose and iodine contrast as those for single-energy (SE) images using five dual-energy (DE) scanners with DE techniques: two generations of fast kV switching (FKS), two generations of dual source (DS), and one split filter (SF). METHODS A water-bath phantom with a diameter of 300 mm, which contains one rod-shaped phantom made of a material equivalent to soft-tissue and two rod-shaped phantoms made of diluted iodine (2 and 12 mg/mL), was scanned using both SE (120, 100, and 80 kV) and DE techniques with the same CT dose index in each scanner. The VM energy at which the CT number of the iodine rod is closest to that of each SE tube voltage was determined as the equivalent energy (Eeq). A detectability index (d') was calculated from the noise power spectrum, the task transfer functions, and a task function corresponding to each rod. The percentage of the d' value of the VM image to that of the corresponding SE image was calculated for performance comparison. RESULTS The average percentages of d' of FKS1, FKS2, DS1, DS2, and SF were 84.6%, 96.2%, 94.3%, 107%, and 104% for 120 kV-Eeq; 75.9%, 91.2%, 88.2%, 99.2%, and 82.6% for 100 kV-Eeq; 71.6%, 88.9%, 82.6%, 85.2%, and 62.3% for 80 kV-Eeq, respectively. CONCLUSION The performance of VM images was on the whole inferior to that of SE images especially at low equivalent energy levels, depending on the DE techniques and their generations. KEY POINTS • This study evaluated the performance of VM images with the same dose and iodine contrast as those for SE images using five DE scanners. • The performance of VM images varied with the DE techniques and their generations and was mostly inferior at low equivalent energy levels. • The results highlight the importance of distribution of available dose over the two energy levels and spectral separation for the performance improvement of VM images.
Collapse
Affiliation(s)
- Hiroki Kawashima
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, 920-0942, Japan.
| | - Katsuhiro Ichikawa
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, 920-0942, Japan
| | - Hiroshi Ueta
- Radiology Division, Kanazawa University Hospital, 13-1 Takara-Machi, Kanazawa, 920-8641, Japan
| | - Tadanori Takata
- Radiology Division, Kanazawa University Hospital, 13-1 Takara-Machi, Kanazawa, 920-8641, Japan
| | - Wataru Mitsui
- Radiology Division, Kanazawa University Hospital, 13-1 Takara-Machi, Kanazawa, 920-8641, Japan
| | - Hiroji Nagata
- Section of Radiological Technology, Department of Medical Technology, Kanazawa Medical University Hospital, Daigaku 1-1, Uchinada, Kahoku, 920-0293, Japan
| |
Collapse
|
4
|
Masuda T, Nakaura T, Funama Y, Sato T, Masuda S, Gotanda R, Arao K, Imaizumi H, Arao S, Ono A, Hiratsuka J, Awai K. RADIATION DOSE REDUCTION AT LOW TUBE VOLTAGE WITH CORONARY ARTERY BYPASS GRAFT COMPUTED TOMOGRAPHY ANGIOGRAPHY BASED ON THE CONTRAST NOISE RATIO INDEX. RADIATION PROTECTION DOSIMETRY 2023; 199:527-532. [PMID: 36881907 DOI: 10.1093/rpd/ncad049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 02/08/2023] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
To compare the radiation dose and diagnostic ability of the 100-kVp protocol, based on the contrast noise ratio (CNR) index, during coronary artery bypass graft (CABG) vessels with those of the 120-kVp protocol. For the 120-kVp scans (150 patients), the targeted image level was set at 25 Hounsfield units (HU) (CNR120 = iodine contrast/25 HU). For the 100-kVp scans (150 patients), the targeted noise level was set at 30 HU to obtain the same CNR as in the 120-kVp scans (i.e. using 1.2-fold higher iodine contrast, CNR100 = 1.2 × iodine contrast/(1.2 × 25 HU) = CNR120). We compared the CNRs, radiation doses, detection of CABG vessels and visualisation scores of the scans acquired at 120 and 100 kVp, respectively. At the same CNR, the 100-kVp protocol may help reduce the radiation dose by ⁓30% compared with the 120-kVp protocol, without degradation of diagnostic ability during CABG.
Collapse
Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan
| | - Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Tomoyasu Sato
- Department of Diagnostic Radiology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima 730-8655, Japan
| | - Shouko Masuda
- Department of Radiological Technology, Kawamura clinic Otemachi, Naka-ku, Hiroshima 730-0051, Japan
| | - Rumi Gotanda
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Keiko Arao
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Hiromasa Imaizumi
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Shinichi Arao
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Atsushi Ono
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Junichi Hiratsuka
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| |
Collapse
|
5
|
Lyu P, Liu N, Harrawood B, Solomon J, Wang H, Chen Y, Rigiroli F, Ding Y, Schwartz FR, Jiang H, Lowry C, Wang L, Samei E, Gao J, Marin D. Is it possible to use low-dose deep learning reconstruction for the detection of liver metastases on CT routinely? Eur Radiol 2023; 33:1629-1640. [PMID: 36323984 DOI: 10.1007/s00330-022-09206-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/28/2022] [Accepted: 09/26/2022] [Indexed: 11/06/2022]
Abstract
OBJECTIVES To compare the image quality and hepatic metastasis detection of low-dose deep learning image reconstruction (DLIR) with full-dose filtered back projection (FBP)/iterative reconstruction (IR). METHODS A contrast-detail phantom consisting of low-contrast objects was scanned at five CT dose index levels (10, 6, 3, 2, and 1 mGy). A total of 154 participants with 305 hepatic lesions who underwent abdominal CT were enrolled in a prospective non-inferiority trial with a three-arm design based on phantom results. Data sets with full dosage (13.6 mGy) and low dosages (9.5, 6.8, or 4.1 mGy) were acquired from two consecutive portal venous acquisitions, respectively. All images were reconstructed with FBP (reference), IR (control), and DLIR (test). Eleven readers evaluated phantom data sets for object detectability using a two-alternative forced-choice approach. Non-inferiority analyses were performed to interpret the differences in image quality and metastasis detection of low-dose DLIR relative to full-dose FBP/IR. RESULTS The phantom experiment showed the dose reduction potential from DLIR was up to 57% based on the reference FBP dose index. Radiation decreases of 30% and 50% resulted in non-inferior image quality and hepatic metastasis detection with DLIR compared to full-dose FBP/IR. Radiation reduction of 70% by DLIR performed inferiorly in detecting small metastases (< 1 cm) compared to full-dose FBP (difference: -0.112; 95% confidence interval [CI]: -0.178 to 0.047) and full-dose IR (difference: -0.123; 95% CI: -0.182 to 0.053) (p < 0.001). CONCLUSION DLIR enables a 50% dose reduction for detecting low-contrast hepatic metastases while maintaining comparable image quality to full-dose FBP and IR. KEY POINTS • Non-inferiority study showed that deep learning image reconstruction (DLIR) can reduce the dose to oncological patients with low-contrast lesions without compromising the diagnostic information. • Radiation dose levels for DLIR can be reduced to 50% of full-dose FBP and IR for detecting low-contrast hepatic metastases, while maintaining comparable image quality. • The reduction of radiation by 70% by DLIR is clinically acceptable but insufficient for detecting small low-contrast hepatic metastases (< 1 cm).
Collapse
Affiliation(s)
- Peijie Lyu
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1 East Jianshe Road, Zhengzhou, 450052, Henan Province, China.,Department of Radiology, Duke University Medical Center, 2301 Erwin Rd, Box 3808, Durham, NC, 27710, USA
| | - Nana Liu
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1 East Jianshe Road, Zhengzhou, 450052, Henan Province, China
| | - Brian Harrawood
- Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, 2424 Erwin Road, Suite 302, Durham, NC, 27705, USA
| | - Justin Solomon
- Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, 2424 Erwin Road, Suite 302, Durham, NC, 27705, USA
| | - Huixia Wang
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1 East Jianshe Road, Zhengzhou, 450052, Henan Province, China
| | - Yan Chen
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1 East Jianshe Road, Zhengzhou, 450052, Henan Province, China
| | - Francesca Rigiroli
- Beth Israel Deaconess Medical Center Department of Radiology, Harvard Medical School, 1 Deaconess Rd, 330 Brookline Ave, Boston, MA, 02215, USA
| | - Yuqin Ding
- Department of Radiology, Duke University Medical Center, 2301 Erwin Rd, Box 3808, Durham, NC, 27710, USA.,Department of Radiology, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 20032, China
| | - Fides Regina Schwartz
- Department of Radiology, Duke University Medical Center, 2301 Erwin Rd, Box 3808, Durham, NC, 27710, USA
| | - Hanyu Jiang
- Department of Radiology, Duke University Medical Center, 2301 Erwin Rd, Box 3808, Durham, NC, 27710, USA.,Department of Radiology, West China Hospital of Sichuan University, 37 Guoxue Alley, Chengdu, 610041, Sichuan Province, China
| | - Carolyn Lowry
- Clinical Imaging Physics Group, Duke University Health System, 2424 Erwin Rd, Ste. 302, Durham, NC, 27705, USA
| | - Luotong Wang
- CT Imaging Research Center, GE Healthcare China, No.1 Tongji South Road, Beijing, 100176, China
| | - Ehsan Samei
- Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, 2424 Erwin Road, Suite 302, Durham, NC, 27705, USA
| | - Jianbo Gao
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1 East Jianshe Road, Zhengzhou, 450052, Henan Province, China.
| | - Daniele Marin
- Department of Radiology, Duke University Medical Center, 2301 Erwin Rd, Box 3808, Durham, NC, 27710, USA
| |
Collapse
|
6
|
Markart S, Fischer TS, Wildermuth S, Dietrich TJ, Alkadhi H, Leschka S, Guesewell S, Ditchfield MR, Oezden I, Lutters G, Waelti SL. Organ-based tube current modulation and bismuth eye shielding in pediatric head computed tomography. Pediatr Radiol 2022; 52:2584-2594. [PMID: 35836016 DOI: 10.1007/s00247-022-05410-x] [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: 07/13/2021] [Revised: 12/23/2021] [Accepted: 05/30/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND Exposure of the eye lens to ionizing radiation results in cataract. Several dose optimization techniques to protect the lens are available for computed tomography (CT). OBJECTIVE The radiation dose to the eye lens, volume CT dose index (CTDIvol) and image quality of various methods of dose optimization were evaluated for pediatric head CT: automated tube current modulation (ATCM), automated tube voltage selection (ATVS), organ-based tube current modulation (OBTCM) and bismuth shielding. MATERIALS AND METHODS An anthropomorphic phantom of a 5-year-old child was scanned with nine protocols: no dose optimization technique and then adding different dose optimization techniques alone and in combination. Dose to the eye, thyroid and breast were estimated using metal oxide semiconductor field effect transistor (MOSFET) dosimetry. CTDIvol, influence of timing of shield placement, image noise and attenuation values in 13 regions of interest of the head and subjective image quality were compared. RESULTS The eye shield significantly reduced the eye lens dose when used alone, to a similar degree as when using all software-based techniques together. When used in combination with software-based techniques, the shield reduced the eye lens dose by up to 45% compared to the no dose optimization technique. Noise was significantly increased by the shield, most pronounced in the anterior portion of the eye. CONCLUSION The combination of ATCM, ATVS, OBTCM and a bismuth shield, with the shield placed after acquiring the localizer image, should be considered to reduce the radiation dose to the eye lens in pediatric head CT.
Collapse
Affiliation(s)
- Stefan Markart
- Department of Radiology and Nuclear Medicine, Children's Hospital of Eastern Switzerland, Claudiusstrasse 6, 9006, St. Gallen, Switzerland
- Department of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Tim S Fischer
- Department of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Simon Wildermuth
- Department of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Tobias J Dietrich
- Department of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
- Department of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Hatem Alkadhi
- Department of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Sebastian Leschka
- Department of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Sabine Guesewell
- Clinical Trials Unit, Biostatistics, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Michael R Ditchfield
- Department of Diagnostic Imaging, Monash Children's Hospital, Clayton, Australia
| | - Ismail Oezden
- Radiation Protection and Medical Physics, Cantonal Hospital Aarau, Aarau, Switzerland
| | - Gerd Lutters
- Radiation Protection and Medical Physics, Cantonal Hospital Aarau, Aarau, Switzerland
| | - Stephan L Waelti
- Department of Radiology and Nuclear Medicine, Children's Hospital of Eastern Switzerland, Claudiusstrasse 6, 9006, St. Gallen, Switzerland.
- Department of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland.
| |
Collapse
|
7
|
Low-Dose Abdominal CT for Evaluating Suspected Appendicitis: Recommendations for CT Imaging Techniques and Practical Issues. Diagnostics (Basel) 2022; 12:diagnostics12071585. [PMID: 35885490 PMCID: PMC9320604 DOI: 10.3390/diagnostics12071585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/21/2022] [Accepted: 06/27/2022] [Indexed: 12/04/2022] Open
Abstract
A vast disparity exists between science and practice for CT radiation dose. Despite high-level evidence supporting the use of low-dose CT (LDCT) in diagnosing appendicitis, a recent survey showed that many care providers were still concerned that the low image quality of LDCT may lead to incorrect diagnoses. For successful implementation of LDCT practice, it is important to inform and educate the care providers not only of the scientific discoveries but also of concrete guidelines on how to overcome more practical matters. Here, we discuss CT imaging techniques and other practical issues for implementing LDCT practice.
Collapse
|
8
|
Tao S, Gong H, Michalak G, McCollough C, Leng S, Hu Y. Technical note: Evaluation of Artificial 120-kilovolt computed tomography images for radiation therapy applications. Med Phys 2022; 49:3683-3691. [PMID: 35394074 DOI: 10.1002/mp.15592] [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: 09/03/2021] [Revised: 02/25/2022] [Accepted: 02/28/2022] [Indexed: 11/09/2022] Open
Abstract
PURPOSE The purpose of this work is to evaluate the scaled CT number accuracy of an artificial 120 kV reconstruction technique based on phantom experiments in the context of radiation therapy planning. METHODS An abdomen-shaped electron density phantom was scanned on a clinical CT scanner capable of artificial 120 kV reconstruction using different tube potentials from 70 kV to 150 kV. A series of tissue equivalent phantom inserts (lung, adipose, breast, solid water, liver, inner bone, 30%/50% CaCO3, cortical bone) were placed inside the phantom. Images were reconstructed using a conventional quantitative reconstruction kernel as well as the artificial 120 kV reconstruction kernel. Scaled CT numbers of inserts were measured from images acquired at different kVs and compared with those acquired at 120 kV, which were deemed as the ground truth. The relative error was quantified as the percentage deviation of scaled CT numbers acquired at different tube potentials from their ground truth values acquired at 120 kV. RESULTS Scaled CT numbers measured from images reconstructed using the conventional reconstruction demonstrated a strong kV-dependence. The relative error in scaled CT number ranged from 0.6% (liver insert) to 31.1% (cortical bone insert). The artificial 120 kV reconstruction reduced the kV-dependence, especially for bone tissues. The relative error in scaled CT number was reduced to 0.4% (liver insert) and 2.6% (30% CaCO3 insert) using this technique. When tube potential selection was limited to the range of 90 kV to 150 kV, the relative error was further restrained to <1.2% for all tissue types. CONCLUSION Phantom results demonstrated that using the artificial 120 kV technique, it was feasible to acquire raw projection data at a desired tube potential and then reconstruct images with scaled CT numbers comparable to those obtained directly at 120 kV. In radiotherapy applications, this technique may allow optimization of tube potential without complicating clinical workflow by eliminating the necessity of maintaining multiple sets of CT calibration curves. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Shengzhen Tao
- Department of Radiology, Mayo Clinic, Jacksonville, FL, USA
| | - Hao Gong
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | | | | | - Shuai Leng
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Yanle Hu
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, USA
| |
Collapse
|
9
|
The Image Quality and Diagnostic Performance of CT with Low-Concentration Iodine Contrast (240 mg Iodine/mL) for the Abdominal Organs. Diagnostics (Basel) 2022; 12:diagnostics12030752. [PMID: 35328304 PMCID: PMC8947528 DOI: 10.3390/diagnostics12030752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/11/2022] [Accepted: 03/17/2022] [Indexed: 11/17/2022] Open
Abstract
Purpose: To evaluate the difference between CT examinations using 240 mgI/mL contrast material (CM) and 320 mgI/mL CM in the contrast enhancement of the abdominal organs and the diagnostic performance for focal hepatic lesions. Materials and methods: This retrospective study included 422 CT examinations, using 240 mgI/mL iohexol (Group A, 206 examinations) and 320 mgI/mL ioversol (Group B, 216 examinations), performed between April 2019 and May 2020. Two CT scanners (single-source CT (machine A) and dual-source CT (machine B)) were used to obtain CT images. Two radiologists independently drew regions of interest (ROIs) in the liver, pancreas, spleen, kidney, aorta, portal vein, and paraspinal muscle. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated for each organ. They evaluated the degree of subjective enhancement of the organs and detected/differentiated focal hepatic lesions. Results: The SNR, CNR, and subjective enhancement of most organs were significantly higher in Group B than in Group A (p < 0.05). The sensitivity and specificity for cysts and malignancy were higher than 85.0% in both groups. The sensitivity for hemangioma was lower in Group B (<75%) than in Group A. In Group A, the SNR and CNR were significantly higher in most organs with machine B than with machine A. Conclusion: Although the SNR and CNR of the abdominal organs were lower with 240 mgI/mL CM than with 320 mgI/mL CM, 240 mgI/mL CM was feasible for evaluating the liver. A CT scanner with more advanced specifications may be beneficial for examinations with 240 mgI/mL CM by using lower tube voltage.
Collapse
|
10
|
Sodagari F, Wood CG, Agrawal R, Yaghmai V. Feasibility of sub-second CT angiography of the abdomen and pelvis with very low volume of contrast media, low tube voltage, and high-pitch technique, on a third-generation dual-source CT scanner. Clin Imaging 2021; 82:15-20. [PMID: 34768221 DOI: 10.1016/j.clinimag.2021.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/04/2021] [Accepted: 10/21/2021] [Indexed: 12/18/2022]
Abstract
BACKGROUND Concerns about potential risks of using contrast media in patients with chronic renal insufficiency limit the utilization of CT angiography in this population. PURPOSE To evaluate the feasibility of abdominopelvic CTA with very low volumes of contrast media. MATERIAL AND METHODS In this retrospective study, 20 patients with chronic renal insufficiency underwent high-pitch abdominopelvic (AP) CTA on a third-generation dual-source CT scanner with 30 mL of nonionic iodinated contrast. The homogeneity of intravascular attenuation at the suprarenal aorta, infrarenal aorta, and the right common iliac artery was measured. Image noise, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) were used to assess objective image quality. Subjective image quality was evaluated on a 5-point scale (1 = unacceptable; 5 = excellent). RESULTS Twelve male and eight female patients underwent CTA of the abdomen and pelvis at 80 kVp. Five CTAs also included the chest (CAP). The mean scan duration was 0.78 ± 0.19 s for AP and 0.96 ± 0.06 s for CAP CTAs. The mean ± SD of attenuation at suprarenal aorta, infrarenal aorta, and right common iliac artery were 235.1 ± 68.0, 249.2 ± 61.3, and 254.4 ± 67.7 HU, respectively. The attenuation was homogeneous across vascular levels (P = 0.06). All scans had diagnostic subjective image quality with the median (IQR) of 3.5 (1.75). CNR and SNR were homogeneous across vascular levels (P = 0.08 and P = 0.14, respectively). CONCLUSION Sub-second, high-pitch abdominopelvic CTA with a low volume of contrast in patients with chronic renal insufficiency is technically and clinically feasible with good diagnostic image quality and homogenous attenuation across vascular levels.
Collapse
Affiliation(s)
- Faezeh Sodagari
- Department of Radiology, Northwestern University-Feinberg School of Medicine, Chicago, IL, USA; Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA.
| | - Cecil G Wood
- Department of Radiology, Northwestern University-Feinberg School of Medicine, Chicago, IL, USA.
| | - Rishi Agrawal
- Department of Radiology, Northwestern University-Feinberg School of Medicine, Chicago, IL, USA.
| | - Vahid Yaghmai
- Department of Radiology, Northwestern University-Feinberg School of Medicine, Chicago, IL, USA; Department of Radiological Sciences, University of California, Irvine School of Medicine, Orange, CA, USA.
| |
Collapse
|
11
|
Kulkarni CB, Pullara SK, Prabhu NK, Patel S, Suresh A, Moorthy S. Comparison of Knowledge-based Iterative Model Reconstruction (IMR) with Hybrid Iterative Reconstruction (iDose 4) Techniques for Evaluation of Hepatocellular Carcinomas Using Computed Tomography. Acad Radiol 2021; 28 Suppl 1:S29-S36. [PMID: 32950385 DOI: 10.1016/j.acra.2020.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/04/2020] [Accepted: 08/05/2020] [Indexed: 02/08/2023]
Abstract
RATIONALE AND OBJECTIVES To compare tumor conspicuity of small hepatocellular carcinomas (HCCs) and image quality on knowledge-based iterative model reconstruction low-dose computed tomography (IMR-LDCT) with hybrid iterative reconstruction standard-dose CT (iDose4-SDCT). METHODS Thirty-two patients (mean age 61.9 ± 9.7 years; male:female 27:5; mean body mass index 25.6 ± 3.8 kg/m2) with cirrhosis and 40 HCCs in IMR-LDCT group and 33 patients (mean age 60.1 ± 7.4 years; male:female 28:5; body mass index 26.7 ± 3.2 kg/m2) with cirrhosis and 40 HCCs in iDose4-SDCT group were included in this retrospective study. Objective analysis of reconstructed iDose4 and IMR images was done for contrast-to-noise ratio of HCCs (CNRHCC), image noise, signal-to-noise ratio of portal vein (SNRPV), and inferior vena cava (SNRIVC). Subjective analysis of tumor conspicuity and image quality was done by two independent reviewers in a blinded manner. Mean volume CT dose index, dose length product, and effective dose for both groups were compared. RESULTS The CNRHCC was significantly higher in IMR-LDCT compared to iDose4-SDCT in both arterial phase (AP), p < 0.0001, and delayed phase (DP), p < 0.0001. Image noise was significantly lower in IMR-LDCT compared to iDose4-SDCT in AP, portal venous phase, and DP with p < 0.0001. IMR-LDCT showed significantly higher SNRPV (p < 0.0001) and SNRIVC (p < 0.0001) compared to iDose4-SDCT. On subjective analysis, IMR-LDCT images showed better image quality in AP, portal venous phase, and DP and better tumor conspicuity in AP and DP. IMR-LDCT (21.4 ± 4.6 mSv) achieved 36.9% reduction in the effective dose compared to iDose4-SDCT (33.9 ± 6.2 mSv). CONCLUSION IMR algorithm provides better image quality and tumor conspicuity with considerable decrease in image noise compared to iDose4 reconstruction technique even on LDCT.
Collapse
|
12
|
Sookpeng S, Martin CJ, Krisanachinda A. Effects of tube potential selection together with computed tomography automatic tube current modulation on CT imaging performance. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2021; 41:809-831. [PMID: 33657533 DOI: 10.1088/1361-6498/abebb4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 03/03/2021] [Indexed: 06/12/2023]
Abstract
The effects of tube potential selection with a computed tomography (CT) automatic tube current modulation (ATCM) system on radiation dose and image quality have been investigated on a Canon CT scanner. The use of different values of tube voltage for imaging, and the appropriate settings of the ATCM system, were evaluated. The custom-made phantom consisted of three sections of different sizes with inserts of various materials. It was scanned using tube potentials of 80-140 kV and different image quality ATCM settings. CTDIvoland image quality in terms of noise, contrast, and contrast-to-noise ratio (CNR) for air, polyethylene (PE), acrylic, polyoxymethylene (POM) and polyvinylchloride (PVC) were analysed. A figure of merit (FOM) was estimated by combining CNR and CTDIvol. CTDIvolvalues were similar for all values of tube voltage and individual image quality ATCM settings when tube current was not restricted by the maximum value. The contrasts were independent of ATCM image quality setting, but CNR increased at the higher image quality level as image noise decreased. Both contrast and CNR decreased with increasing tube voltage for PVC and PE, but increased for POM and acrylic. PVC was the only insert material for which there was a significant improvement in contrast at lower tube potentials. FOM indicated that standard (SD = 10) and low dose (SD = 12.5) ATCM settings might be appropriate. The optimum tube voltage settings for imaging the PVC was 80-100 kV, but not for the lower contrast POM and acrylic, for which the standard tube voltage setting of 120 kV was better. The tube potential should be carefully set to gain radiological protection optimisation and keep the radiation dose as low as possible. Results indicate that 100 kV is likely to be appropriate for imaging small and medium-sized Thai patients when iodine contrast is used.
Collapse
Affiliation(s)
- S Sookpeng
- Department of Radiological Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand
| | - C J Martin
- Department of Clinical Physics and Bio-engineering, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - A Krisanachinda
- Department of Radiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| |
Collapse
|
13
|
Computed Tomography Techniques, Protocols, Advancements, and Future Directions in Liver Diseases. Magn Reson Imaging Clin N Am 2021; 29:305-320. [PMID: 34243919 DOI: 10.1016/j.mric.2021.05.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Computed tomography (CT) is often performed as the initial imaging study for the workup of patients with known or suspected liver disease. Our article reviews liver CT techniques and protocols in clinical practice along with updates on relevant CT advances, including wide-detector CT, radiation dose optimization, and multienergy scanning, that have already shown clinical impact. Particular emphasis is placed on optimizing the late arterial phase of enhancement, which is critical to evaluation of hepatocellular carcinoma. We also discuss emerging techniques that may soon influence clinical care.
Collapse
|
14
|
Yoo J, Lee JM, Yoon JH, Joo I, Lee ES, Jeon SK, Jang S. Comparison of low kVp CT and dual-energy CT for the evaluation of hypervascular hepatocellular carcinoma. Abdom Radiol (NY) 2021; 46:3217-3226. [PMID: 33713160 DOI: 10.1007/s00261-020-02888-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/25/2020] [Accepted: 11/27/2020] [Indexed: 01/19/2023]
Abstract
PURPOSE To compare lesion conspicuity and image quality of arterial phase images obtained from low kVp (90-kVp) and dual-energy (DE) scans for the evaluation of hypervascular hepatocellular carcinoma (HCC). METHODS This retrospective study included 229 patients with HCC who underwent either 90 kVp (n = 106) or DE scan (80- and 150-kVp with a tin filter) (n = 123) during the arterial phase. DE scans were reconstructed into a linearly blended image with a mixed ratio of 0.6 (60% 80kVp and 40% 150 kVp) and post-processed for 40 keV and 50 keV images. The contrast-to-noise ratio (CNR) of HCC to the liver and image noise was measured. Lesion conspicuity, liver parenchymal image quality, and overall image preference were assessed qualitatively by three independent radiologists. RESULTS DE 40 keV images had the highest CNR of HCC, and DE blended images had the lowest image noise among four image sets (p = 0.01 and p < 0.001, respectively). There was no significant difference in mean volume CT dose index and dose-length product between DE and low kVp scan (ps > 0.05). For qualitative analyses, DE blended images had the highest scores for image quality and overall image preference (ps < 0.001). CONCLUSION At an equal radiation dose, DE 40 keV showed higher CNR of HCC and DE blended image showed higher image quality and image preference compared with low kVp CT.
Collapse
Affiliation(s)
- Jeongin Yoo
- Department of Radiology, Seoul National University Hospital, Seoul, Korea
| | - Jeong Min Lee
- Department of Radiology, Seoul National University Hospital, Seoul, Korea.
- Department of Radiology, Seoul National University College of Medicine, Seoul, Korea.
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea.
- Department of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Daehak-ro 101, Jongno-gu, Seoul, 03080, Korea.
| | - Jeong Hee Yoon
- Department of Radiology, Seoul National University Hospital, Seoul, Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
| | - Ijin Joo
- Department of Radiology, Seoul National University Hospital, Seoul, Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea
| | - Eun Sun Lee
- Department of Radiology, Chung-Ang University Hospital, Seoul, Korea
| | - Sun Kyung Jeon
- Department of Radiology, Seoul National University Hospital, Seoul, Korea
| | - Siwon Jang
- Department of Radiology, Seoul National University Boramae Hospital, Seoul, Korea
| |
Collapse
|
15
|
Tao S, Sheedy E, Bruesewitz M, Weber N, Williams K, Halaweish A, Schmidt B, Williamson E, McCollough C, Leng S. Technical Note: kV-independent coronary calcium scoring: A phantom evaluation of score accuracy and potential radiation dose reduction. Med Phys 2021; 48:1307-1314. [PMID: 33332626 DOI: 10.1002/mp.14663] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/04/2020] [Accepted: 12/08/2020] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To determine the accuracy of CT number and calcium score of a kV-independent technique based on an artificial 120 kV reconstruction, and its potential to reduce radiation dose. METHODS Anthropomorphic chest phantoms were scanned on a third-generation dual-source CT system equipped with the artificial 120 kV reconstruction. First, a phantom module containing a 20-mm diameter hydroxyapatite (HA) insert was scanned inside the chest phantoms at different tube potentials (70-140 kV) to evaluate calcium CT number accuracy. Next, three small HA inserts (diameter/length = 5 mm) were inserted into a pork steak and scanned inside the phantoms to evaluate calcium score accuracy at different kVs. Finally, the same setup was scanned using automatic exposure control (AEC) at 120 kV, and then with automatic kV selection (auto-kV). Phantoms were also scanned at 120 kV using a size-dependent mA chart. CT numbers of soft tissue and calcium were measured from different kV images. Calcium score of each small HA insert was measured using commercial software. RESULTS The CT number difference from 120 kV was small with tube potentials from 90 to 140 kV for both soft tissue and calcium (maximal difference of 4/5 HU, respectively). Consistent calcium scores were obtained from images of different kVs compared to 120 kV, with a relative difference <8%. Auto-kV provided a 25-34% dose reduction compared to AEC alone. CONCLUSION A kV-independent calcium scoring technique can produce artificial 120 kV images with consistent soft tissue and calcium CT numbers compared to standard 120 kV examinations. When coupled with auto-kV, this technique can reduce radiation by 25-34% compared to that with AEC alone, while providing consistent calcium scores as that of standard 120 kV examinations.
Collapse
Affiliation(s)
- Shengzhen Tao
- Department of Radiology, Mayo Clinic, Jacksonville, FL, USA
| | - Emily Sheedy
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | | | - Nikkole Weber
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Kyle Williams
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | | | - Bernhard Schmidt
- Siemens Healthineers, Siemensstraße 1, Forchheim, 91301, Germany
| | | | | | - Shuai Leng
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| |
Collapse
|
16
|
Singh R, Wu W, Wang G, Kalra MK. Artificial intelligence in image reconstruction: The change is here. Phys Med 2020; 79:113-125. [DOI: 10.1016/j.ejmp.2020.11.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 11/06/2020] [Accepted: 11/07/2020] [Indexed: 12/19/2022] Open
|
17
|
Yoon JH, Lee JM, Lee DH, Joo I, Jeon JH, Ahn SJ, Kim ST, Cho EJ, Lee JH, Yu SJ, Kim YJ, Yoon JH. A Comparison of Biannual Two-Phase Low-Dose Liver CT and US for HCC Surveillance in a Group at High Risk of HCC Development. Liver Cancer 2020; 9:503-517. [PMID: 33083277 PMCID: PMC7548851 DOI: 10.1159/000506834] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 02/26/2020] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND AND AIMS Biannual ultrasonography (US) is a current recommendation for hepatocellular carcinoma (HCC) surveillance in a high-risk group. The sensitivity of US, however, has been low in patients with a high risk of developing HCC. We aimed to compare sensitivity for HCC of biannual US and two-phase low-dose computed tomography (LDCT) in patients with a high risk of HCC. METHODS In this prospective single-arm study, participants with an annual risk of HCC greater than 5% (based on a risk index of ≥2.33) and who did not have a history of HCC were enrolled from November 2014 to July 2016. Participants underwent paired biannual US and two-phase LDCT 1-3 times. Two-phase LDCT included arterial and 3-min delayed phases. The sensitivity, specificity, and positive predictive value of HCC detection using US and two-phase LDCT were compared using a composite algorithm as a standard of reference. RESULTS Of the 139 enrolled participants, 137 underwent both the biannual US and two-phase LDCT at least once and had follow-up images. Among them, 27 cases of HCC (mean size: 14 ± 4 mm) developed in 24 participants over 1.5 years. Two-phase LDCT showed a significantly higher sensitivity (83.3% [20/24] vs. 29.2% [7/24], p < 0.001) and specificity (95.6% [108/113] vs. 87.7% [99/113], p =0.03) than US. A false-positive result was reported in 14 participants at US and 5 participants at two-phase LDCT, resulting in a significantly higher positive predictive value of two-phase LDCT (33.3% [7/21] vs. 80% [20/25], p < 0.001). CONCLUSIONS Patients with a risk index ≥2.33 showed a high annual incidence of HCC development in our study, and two-phase LDCT showed significantly higher sensitivity and specificity for HCC detection than US.
Collapse
Affiliation(s)
- Jeong Hee Yoon
- Radiology, Seoul National University Hospital, Seoul, Republic of Korea,College of Medicine, Seoul, Republic of Korea
| | - Jeong Min Lee
- Radiology, Seoul National University Hospital, Seoul, Republic of Korea,College of Medicine, Seoul, Republic of Korea,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea,*Jeong Min Lee, Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080 (Republic of Korea),
| | - Dong Ho Lee
- Radiology, Seoul National University Hospital, Seoul, Republic of Korea,College of Medicine, Seoul, Republic of Korea
| | - Ijin Joo
- Radiology, Seoul National University Hospital, Seoul, Republic of Korea,College of Medicine, Seoul, Republic of Korea
| | - Ju Hyun Jeon
- Radiology, Seoul National University Hospital, Seoul, Republic of Korea,College of Medicine, Seoul, Republic of Korea
| | - Su Joa Ahn
- Radiology, Seoul National University Hospital, Seoul, Republic of Korea,College of Medicine, Seoul, Republic of Korea
| | - Seung-taek Kim
- Radiology, Seoul National University Hospital, Seoul, Republic of Korea,College of Medicine, Seoul, Republic of Korea
| | - Eun Ju Cho
- Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jeong-Hoon Lee
- Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Su Jong Yu
- Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Yoon Jun Kim
- Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jung-Hwan Yoon
- Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| |
Collapse
|
18
|
Choi MH, Lee YJ, Jung SE. A LESSON FROM AUTOMATIC TUBE VOLTAGE SELECTION: FEASIBILITY OF 100 kVp IN PORTAL VENOUS PHASE ABDOMINAL CT. RADIATION PROTECTION DOSIMETRY 2020; 188:424-431. [PMID: 31998958 DOI: 10.1093/rpd/ncz302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/17/2019] [Accepted: 12/23/2019] [Indexed: 06/10/2023]
Abstract
PURPOSE To evaluate the relationship between ATVS-recommended tube voltage and patient body habitus and to compare radiation dose and diagnostic performance between fixed 120-kVp and ATVS protocols in portal venous phase abdomen CT. METHODS A total of 907 portal venous phase abdominal CTs were evaluated. Radiation dose in the ATVS protocol was compared according to tube voltage (80, 100 or 120 kVp). Quantitative image analysis and diagnostic performance were compared between 81 pairs of CT using ATVS and fixed 120-kVp protocols. RESULTS Most CT examinations with ATVS were performed with 80 or 100 kVp. The average reduction rate of radiation dose in the ATVS protocol was 15.4%. There was no significant difference in diagnostic performance (p = 0.388) between ATVS and fixed 120-kVp protocols. CONCLUSIONS In conclusion, ATVS frequently selected 80 or 100 kVp for portal venous phase abdominal CT without impairing the diagnostic performance, even with filtered back projection.
Collapse
Affiliation(s)
- Moon Hyung Choi
- Department of Radiology, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
- Catholic Smart Imaging Center, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
- Department of Radioogy, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Young Joon Lee
- Department of Radiology, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
- Catholic Smart Imaging Center, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
- Department of Radioogy, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Seung Eun Jung
- Department of Radiology, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
- Catholic Smart Imaging Center, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
- Department of Radioogy, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| |
Collapse
|
19
|
|
20
|
Automatic Tube Current Modulation and Tube Voltage Selection in Pediatric Computed Tomography: A Phantom Study on Radiation Dose and Image Quality. Invest Radiol 2019; 54:265-272. [PMID: 30562273 PMCID: PMC6484681 DOI: 10.1097/rli.0000000000000537] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVES The aim of this study was to investigate the effects of a modern automatic tube current modulation (ATCM) and automatic tube voltage selection (ATVS) system on radiation dose and image quality in pediatric head, and torso computed tomography (CT) examinations for various clinical indications. MATERIALS AND METHODS Four physical anthropomorphic phantoms that represent the average individual as neonate, 1-year-old, 5-year-old, and 10-year-old child were used. Standard head, thorax, and abdomen/pelvis acquisitions were performed with (1) fixed tube current, (2) ATCM, and (3) ATVS. Acquisitions were performed at various radiation dose levels to generate images at different levels of quality. Reference volume CT dose index (CTDIvol), reference image noise, and reference contrast-to-noise ratios were determined. The potential dose reductions with ATCM and ATVS were assessed. RESULTS The percent reduction of CTDIvol with ATCM ranged from 8% to 24% for head, 16% to 39% for thorax, and 25% to 41% for abdomen/pelvis. The percent reduction of CTDIvol with ATVS varied on the clinical indication. In CT angiography, ATVS resulted to the highest dose reduction, which was up to 70% for head, 77% for thorax, and 34% for abdomen/pelvis. In noncontrast examinations, ATVS increased dose by up to 21% for head, whereas reduced dose by up to 34% for thorax and 48% for abdomen/pelvis. CONCLUSIONS In pediatric CT, the use of ATCM significantly reduces radiation dose and maintains image noise. The additional use of ATVS reduces further the radiation dose for thorax and abdomen/pelvis, and maintains contrast-to-noise ratio for the specified clinical diagnostic task.
Collapse
|
21
|
Moloney F, Twomey M, James K, Kavanagh RG, Fama D, O'Neill S, Grey TM, Moore N, Murphy MJ, O'Connor OJ, Maher MM. A phantom study of the performance of model-based iterative reconstruction in low-dose chest and abdominal CT: When are benefits maximized? Radiography (Lond) 2019; 24:345-351. [PMID: 30292504 DOI: 10.1016/j.radi.2018.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 03/26/2018] [Accepted: 04/23/2018] [Indexed: 01/09/2023]
Abstract
INTRODUCTION The aim of this study was to assess and compare the effects of CT image reconstruction techniques on low-dose CT image quality using phantoms. METHODS Anthropomorphic torso and spatial/contrast-resolution phantoms were scanned at decreasing tube currents between 400 and 10 mA. CT thorax and abdomen/pelvis series were reconstructed with filtered back projection (FBP) alone, combined 40% adaptive statistical iterative reconstruction & FBP (ASIR40), and model-based iterative reconstruction (MBIR) [(resolution-preference 05 (RP05) and RP20 in the thorax and RP05 and noise-reduction 05 (NR05) in the abdomen)]. Two readers rated image quality quantitatively and qualitatively. RESULTS In thoracic CT, objective image noise on MBIR RP05 data sets outperformed FBP at 200, 100, 50 and 10 mA and outperformed ASIR40 at 50 and 10 mA (p < 0.001). MBIR RP20 outperformed FBP at 50 and 10 mA and outperformed ASIR40 at 10 mA (p < 0.001). Compared with both FBP and ASIR40, MBIR RP05 demonstrated significantly better signal-to-noise ratio (SNR) at 10 mA. In abdomino-pelvic CT, MBIR RP05 and NR05 outperformed FBP and ASIR at all tube current levels for objective image noise. NR05 demonstrated greater SNR at 200, 100, 50 and 10 mA and RP05 demonstrated greater SNR at 50 and 10 mA compared with both FBP and ASIR. MBIR images demonstrated better subjective image quality scores. Spatial resolution, low-contrast detectability and contrast-to-noise ratio (CNR) were comparable between image reconstruction techniques. CONCLUSION CTs reconstructed with MBIR have lower image noise and improved image quality compared with FBP and ASIR. These effects increase with reduced radiation exposure confirming optimal use for low-dose CT imaging.
Collapse
Affiliation(s)
- F Moloney
- Department of Radiology, Cork University Hospital, Cork, Ireland; College of Medicine & Health, University College Cork, Cork, Ireland
| | - M Twomey
- Department of Radiology, Cork University Hospital, Cork, Ireland; College of Medicine & Health, University College Cork, Cork, Ireland
| | - K James
- Department of Radiology, Cork University Hospital, Cork, Ireland; College of Medicine & Health, University College Cork, Cork, Ireland
| | - R G Kavanagh
- Department of Radiology, Cork University Hospital, Cork, Ireland; College of Medicine & Health, University College Cork, Cork, Ireland.
| | - D Fama
- Department of Radiology, Cork University Hospital, Cork, Ireland
| | - S O'Neill
- Department of Radiology, Cork University Hospital, Cork, Ireland; College of Medicine & Health, University College Cork, Cork, Ireland
| | - T M Grey
- Department of Radiology, Cork University Hospital, Cork, Ireland
| | - N Moore
- Department of Radiology, Cork University Hospital, Cork, Ireland; College of Medicine & Health, University College Cork, Cork, Ireland
| | - M J Murphy
- Department of Radiology, Cork University Hospital, Cork, Ireland
| | - O J O'Connor
- Department of Radiology, Cork University Hospital, Cork, Ireland; College of Medicine & Health, University College Cork, Cork, Ireland; APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - M M Maher
- Department of Radiology, Cork University Hospital, Cork, Ireland; College of Medicine & Health, University College Cork, Cork, Ireland; APC Microbiome Ireland, University College Cork, Cork, Ireland
| |
Collapse
|
22
|
Nakamura Y, Higaki T, Tatsugami F, Zhou J, Yu Z, Akino N, Ito Y, Iida M, Awai K. Deep Learning-based CT Image Reconstruction: Initial Evaluation Targeting Hypovascular Hepatic Metastases. Radiol Artif Intell 2019; 1:e180011. [PMID: 33937803 DOI: 10.1148/ryai.2019180011] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 06/03/2019] [Accepted: 07/05/2019] [Indexed: 02/07/2023]
Abstract
Purpose To evaluate the effect of a deep learning-based reconstruction (DLR) method on the conspicuity of hypovascular hepatic metastases on abdominal CT images. Materials and Methods This retrospective study with institutional review board approval included 58 patients with hypovascular hepatic metastases. A radiologist recorded the standard deviation of attenuation in the paraspinal muscle as the image noise and the contrast-to-noise ratio (CNR). CNR was calculated as region of interest ([ROI]L - ROIT)/N, where ROIL is the mean liver parenchyma attenuation, ROIT, the mean tumor attenuation, and N, the noise. Two other radiologists graded the conspicuity of the liver lesion on a five-point scale where 1 is unidentifiable and 5 is detected without diagnostic compromise. Only the smallest liver lesion in each patient, classified as smaller or larger than 10 mm, was evaluated. The difference between hybrid iterative reconstruction (IR) and DLR images was determined by using a two-sided Wilcoxon signed-rank test. Results The image noise was significantly lower, and the CNR was significantly higher on DLR images than hybrid IR images (median image noise: 19.2 vs 12.8 HU, P < .001; median CNR: tumors < 10 mm: 1.9 vs 2.5; tumors > 10 mm: 1.7 vs 2.2, both P < .001). The scores for liver lesions were significantly higher for DLR images than hybrid IR images (P < .01 for both in tumors smaller or larger than 10 mm). Conclusion DLR improved the quality of abdominal CT images for the evaluation of hypovascular hepatic metastases.© RSNA, 2019Supplemental material is available for this article.
Collapse
Affiliation(s)
- Yuko Nakamura
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Toru Higaki
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Fuminari Tatsugami
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Jian Zhou
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Zhou Yu
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Naruomi Akino
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Yuya Ito
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Makoto Iida
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| | - Kazuo Awai
- Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan 734-8551 (Y.N., T.H., F.T., M.I., K.A.); Canon Medical Research USA, Vernon Hills, Ill (J.Z., Z.Y.); and Canon Medical Systems, Tochigi, Japan (N.A., Y.I.)
| |
Collapse
|
23
|
Weight-adapted ultra-low-dose pancreatic perfusion CT: radiation dose, image quality, and perfusion parameters. Abdom Radiol (NY) 2019; 44:2196-2204. [PMID: 30790008 DOI: 10.1007/s00261-019-01938-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PURPOSE We evaluate the reliability and feasibility of weight-adapted ultra-low-dose pancreatic perfusion CT. METHODS A total of 100 (47 men, 53 women) patients were enrolled prospectively and were assigned to five groups (A, B, C, D, and E) with different combination of tube voltage and tube current according to their body weight. Radiation dose parameters including volume CT dose index (CTDI) and dose-length product (DLP) were recorded. Image quality was evaluated both subjectively and objectively (noise, signal-to-noise ratio, contrast-to-noise ratio). Perfusion parameters including blood flow (BF), blood volume (BV), and permeability (PMB) were measured. The dose, image quality measurements, and perfusion parameters were compared between the five groups using one-way analysis of variance (ANOVA). RESULTS Radiation dose reached 8.7 mSv in patients under 50 kg and was 18.9 mSv in patients above 80 kg. The mean subjective image quality score was above 4.45 on a 5-point scale with good agreement between two radiologists. Groups A-D had equivalent performance on objective image quality (P > 0.05), while Group E performed even better (P < 0.05). No significant differences emerged in comparison with perfusion parameters (BF, BV, PMB) of normal pancreas parenchyma between the five groups. CONCLUSION Weight-adapted ultra-low-dose pancreatic perfusion CT can effectively reduce radiation dose without prejudice to image quality, and the perfusion parameters of normal parenchyma are accurate and reliable.
Collapse
|
24
|
Parakh A, Negreros-Osuna AA, Patino M, McNulty F, Kambadakone A, Sahani DV. Low-keV and Low-kVp CT for Positive Oral Contrast Media in Patients with Cancer: A Randomized Clinical Trial. Radiology 2019; 291:620-629. [PMID: 30964423 DOI: 10.1148/radiol.2019182393] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Background Substantial gain in the attenuation of iodine on low-kVp and dual-energy CT processed low-keV virtual monochromatic images provides an opportunity for customization of positive oral contrast media administration. Purpose To perform an intrapatient comparison of bowel labeling, opacification, and taste preference with iodinated oral contrast medium (ICM) in standard (sICM) and 25%-reduced (rICM) concentrations at low tube voltage (100 kVp) or on low-energy (50-70 keV) virtual monochromatic images compared with barium-based oral contrast medium (BCM) at 120 kVp. Materials and Methods In this prospective clinical trial, 200 adults (97 men, 103 women; mean age, 63 years ± 13 [standard deviation]) who weighed less than 113 kg and who were undergoing oncologic surveillance (from April 2017 to July 2018) and who had previously undergone 120-kVp abdominopelvic CT with BCM randomly received sICM (7.2 g iodine) or rICM (5.4 g iodine) and underwent 100-kVp CT or dual-energy CT (80/140 kVp) scans to be in one of four groups (n = 50 each): sICM/100 kVp, rICM/100 kVp, sICM/dual-energy CT, and rICM/dual-energy CT. Qualitative analysis was performed for image quality (with a five-point scale), extent of bowel labeling, and homogeneity of opacification (with a four-point scale). Intraluminal attenuation of opacified small bowel was measured. A post-CT patient survey was performed to indicate contrast medium preference, taste of ICM (with a five-point scale), and adverse effects. Data were analyzed with analogs of analysis of variance. Results All CT studies were of diagnostic image quality (3.4 ± 0.3), with no difference in the degree of bowel opacification between sICM and rICM (P > .05). Compared with BCM/120 kVp (282 HU ± 73), mean attenuation was 78% higher with sICM/100 kVp (459 HU ± 282) and 26%-121% higher at sICM/50-65 keV (50 keV = 626 HU ± 285; 65 keV = 356 HU ± 171). With rICM, attenuation was 46% higher for 100 kVp (385 HU ± 215) and 19%-108% higher for 50-65 keV (50 keV = 567 HU ± 270; 65 keV = 325 HU ± 156) compared with BCM (P < .05). A total of 171 of 200 study participants preferred ICM to BCM, with no taste differences between sICM and rICM (3.9 ± 0.6). Fifteen participants had diarrhea with BCM, but none had diarrhea with ICM. Conclusion A 25%-reduced concentration of iodinated oral contrast medium resulted in acceptable bowel labeling while yielding substantially higher luminal attenuation at low-kVp and low-keV CT examinations with improved preference in patients undergoing treatment for cancer. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Laghi in this issue.
Collapse
Affiliation(s)
- Anushri Parakh
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., A.A.N., M.P., F.M., A.K., D.V.S.); Department of Radiology, Hospital Universitario Jose Eleuterio Gonzalez, Monterrey, Mexico (A.A.N.); and Department of Radiology, University of Washington, Seattle, Wash (D.V.S.)
| | - Adrian Antonio Negreros-Osuna
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., A.A.N., M.P., F.M., A.K., D.V.S.); Department of Radiology, Hospital Universitario Jose Eleuterio Gonzalez, Monterrey, Mexico (A.A.N.); and Department of Radiology, University of Washington, Seattle, Wash (D.V.S.)
| | - Manuel Patino
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., A.A.N., M.P., F.M., A.K., D.V.S.); Department of Radiology, Hospital Universitario Jose Eleuterio Gonzalez, Monterrey, Mexico (A.A.N.); and Department of Radiology, University of Washington, Seattle, Wash (D.V.S.)
| | - Fredrick McNulty
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., A.A.N., M.P., F.M., A.K., D.V.S.); Department of Radiology, Hospital Universitario Jose Eleuterio Gonzalez, Monterrey, Mexico (A.A.N.); and Department of Radiology, University of Washington, Seattle, Wash (D.V.S.)
| | - Avinash Kambadakone
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., A.A.N., M.P., F.M., A.K., D.V.S.); Department of Radiology, Hospital Universitario Jose Eleuterio Gonzalez, Monterrey, Mexico (A.A.N.); and Department of Radiology, University of Washington, Seattle, Wash (D.V.S.)
| | - Dushyant V Sahani
- From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, White 270, Boston, MA 02114 (A.P., A.A.N., M.P., F.M., A.K., D.V.S.); Department of Radiology, Hospital Universitario Jose Eleuterio Gonzalez, Monterrey, Mexico (A.A.N.); and Department of Radiology, University of Washington, Seattle, Wash (D.V.S.)
| |
Collapse
|
25
|
Lv P, Zhou Z, Liu J, Chai Y, Zhao H, Guo H, Marin D, Gao J. Can virtual monochromatic images from dual-energy CT replace low-kVp images for abdominal contrast-enhanced CT in small- and medium-sized patients? Eur Radiol 2018; 29:2878-2889. [DOI: 10.1007/s00330-018-5850-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 09/29/2018] [Accepted: 10/22/2018] [Indexed: 01/25/2023]
|
26
|
Masuda T, Funama Y, Nakaura T, Tahara M, Yamashita Y, Kiguchi M, Imada N, Sato T, Awai K. Radiation Dose Reduction with a Low-Tube Voltage Technique for Pediatric Chest Computed Tomographic Angiography Based on the Contrast-to-Noise Ratio Index. Can Assoc Radiol J 2018; 69:390-396. [DOI: 10.1016/j.carj.2018.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Revised: 03/08/2018] [Accepted: 05/16/2018] [Indexed: 10/28/2022] Open
Abstract
Introduction The aim of this study was to evaluate the radiation dose and image quality at low tube-voltage pediatric chest computed tomographic angiography (CTA) that applies the same contrast-to-noise ratio (CNR) index as the standard tube voltage technique. Materials and Methods Contrast-enhanced chest CTA scans of 100 infants were acquired on a 64-row multidetector computed tomography (MDCT) scanner. In the retrospective study, we evaluated 50 images acquired at 120 kVp; the image noise level was set at 25 Hounsfield units. In the prospective study, we used an 80-kVp protocol; the image noise level was 40 Hounsfield units because the iodine contrast was 1.6 times higher than on 120-kVp scans; the CNR was as in the 120-kVp protocol. We compared the CT number, image noise, CT dose index volume (CTDIvol), and the dose-length product on scans acquired with the 2 protocols. A diagnostic radiologist and a pediatric cardiologist visually evaluated all CTA images. Results The mean CTDIvol and the mean dose-length product were 0.5 mGy and 7.8 mGy-cm for 80- and 1.2 mGy and 20.8 mGy-cm for 120-kVp scans, respectively ( P < .001). The mean CTDIvol was 42% lower at 80 kVp than at 120 kVp, and there was no significant difference in the visual scores assigned to the CTA images ( P = .28). Conclusions With the CNR index being the same at 80-kVp and 120-kVp imaging, the radiation dose delivered to infants subjected to chest CTA can be reduced without degradation of the image quality.
Collapse
Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Tsuchiya General Hospital, Hiroshima, Japan
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Masahiro Tahara
- Department of Pediatric Cardiology, Tsuchiya General Hospital, Hiroshima, Japan
| | - Yukari Yamashita
- Department of Radiological Technology, Tsuchiya General Hospital, Hiroshima, Japan
| | - Masao Kiguchi
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Naoyuki Imada
- Department of Radiological Technology, Tsuchiya General Hospital, Hiroshima, Japan
| | - Tomoyasu Sato
- Department of Diagnostic Radiology, Tsuchiya General Hospital, Hiroshima, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| |
Collapse
|
27
|
Masuda T, Funama Y, Nakaura T, Satou T, Okimoto T, Yamashita Y, Imada N, Awai K. Radiation Dose Reduction at Low Tube Voltage CCTA Based on the CNR Index. Acad Radiol 2018; 25:1298-1304. [PMID: 29599007 DOI: 10.1016/j.acra.2018.01.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 01/18/2018] [Accepted: 01/19/2018] [Indexed: 01/04/2023]
Abstract
RATIONALE AND OBJECTIVES We compared the radiation dose and diagnostic accuracy on 120- and 100-kVp coronary computed tomography angiography (CCTA) scans whose contrast-to-noise ratio (CNR) was the same. MATERIALS AND METHODS We studied 1311 coronary artery segments from 100 patients. For 120-kVp scans, the targeted image level was set at 25 Hounsfield units (HU). For 100-kVp scans, the targeted noise level was set at 30 HU to obtain the same CNR as at 120 kVp. We compared the CNR and the radiation dose on scans acquired at 120 and 100 kVp. Invasive coronary angiography (ICA) images were evaluated by an interventional coronary angiography specialist, and CCTA images were evaluated by a radiologist. Coronary artery disease was defined as a luminal narrowing ≧50% for ICA and CCTA. With ICA considered the gold standard, the diagnostic accuracy (sensitivity, specificity, positive predictive value, and negative predictive value) was analyzed on both 120- and 100-kVp CCTA images. We also compared the diagnostic accuracy for area under the receiver operating characteristic curve of the ICA and CCTA performed at 120 and 100 kVp. Two blinded observers visually evaluated the septal branch. RESULTS The mean dose-length product was 48% lower at 100 kVp than at 120 kVp (P < .01). Under the 120-kVp CCTA protocol, the area under the curve, 95% confidence interval, sensitivity, specificity, positive predictive value, and negative predictive value were 0.94%, 0.91%-0.96%, 94.0%, 93.0%, 82.3%, and 98.1%, respectively; at 100 kVp these values were 0.94%, 0.92%-0.97%, 96.1%, 92.0%, 85.2%, and 98.0%, respectively. Area under the receiver operating characteristic curve analysis revealed no significant difference in diagnostic accuracy between the two protocols (P = .87). CONCLUSIONS At the same CNR, the 100-kVp CCTA protocol may help to reduce the radiation dose by approximately 50% compared to the 120-kVp protocol without degradation of diagnostic accuracy.
Collapse
|
28
|
Paper-based 3D printing of anthropomorphic CT phantoms: Feasibility of two construction techniques. Eur Radiol 2018; 29:1384-1390. [PMID: 30116957 DOI: 10.1007/s00330-018-5654-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 06/27/2018] [Accepted: 07/04/2018] [Indexed: 12/13/2022]
Abstract
OBJECTIVES To develop and evaluate methods for assembling radiopaque printed paper sheets to realistic patient phantoms for CT dose and image quality testing. METHODS CT images of two patients were radiopaque printed with aqueous potassium iodide solution (0.6 g/ml) on paper. Two methods were developed for assembling the paper sheets to head and neck phantoms. (1) Printed sheets were fed to a paper-based 3D printer along with corresponding 3D printable STL files. (2) Paper stacks of 5-mm thickness were glued with toner, cut to the patient shape and assembled to a phantom. In a sample application study, both phantoms were examined with five different tube current settings. Images were reconstructed using filtered-back projection (FBP) and iterative reconstruction (AIDR 3D) with three strength levels. Dose length product (DLP), signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNRs) were analysed. Data were analysed using 2-way analysis of variance (ANOVA). RESULTS Both methods achieved anthropomorphic phantoms with detailed patient anatomy. The 3D printer yielded a precise reproduction of the external patient shape, but caused visible glue artefacts. Gluing with toner avoided these artefacts and yielded more flexibility with regard to phantom size. In the sample application study, non-inferior SNR and CNR and up to 83.7% lower DLP were achieved on the phantoms with AIDR 3D compared with FBP. CONCLUSIONS Two methods for assembling radiopaque printed paper sheets to phantoms of individual patients are presented. The sample application demonstrates potential for simulation of patient imaging and systematic CT dose and image quality assessment. KEY POINTS • Two methods were developed to create realistic CT phantoms of individual patients from radiopaque printed paper sheets. • Analysis of five tube current and four reconstruction settings on two radiopaque 3D printed patient phantoms yielded non-inferior SNR and CNR and up to 83.7% lower dose with iterative reconstruction in comparison with filtered back projection. • Radiopaque 3D printed phantoms can simulate patients and allow systematic analysis of CT dose and image quality parameters.
Collapse
|
29
|
Effect of arm position, presence of medical devices, and off-centering during acquisition of scout image on automatic tube voltage selection and current modulation in pediatric chest CT. PLoS One 2018; 13:e0195807. [PMID: 29664918 PMCID: PMC5903633 DOI: 10.1371/journal.pone.0195807] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 03/29/2018] [Indexed: 11/19/2022] Open
Abstract
PURPOSE To evaluate the patients' morphologic factors affecting radiation dose in pediatric chest CT. MATERIALS AND METHODS From November 2013 to May 2015, 315 pediatric chest CT scans were obtained using a CT scanner, and classified into 5 groups according to the patients' age. For each age group, the chest CT scans were divided into two subgroups. A cut-off value used was the 75th percentile of size-specific dose estimates (SSDE), age-specific diagnostic reference level (DRL): less than the 75th percentile of SSDE (Group A, n = 238) and greater than the 75th percentile of SSDE (Group B, n = 77). All CT scans were performed with the same protocol using automatic tube voltage selection and current modulation techniques. The morphologic factors of the patients including body mass index (BMI), arm angles, presence of medical devices in the scan field, and degree of off-centering within the CT gantry were compared between groups A and B. RESULTS Group B showed narrower arm angles on scout and coronal reformatted images, higher frequency of the presence of devices and higher BMI than group A (P < 0.001, P < 0.001; P = 0.018, and P < 0.001, respectively). In multivariate analysis, narrower arm angles, the presence of devices on the scout images and higher BMI were independently associated with higher SSDE (P = 0.001, P = 0.037, and P < 0.001, respectively). CONCLUSIONS During acquisition of the scout images, arms-down position and the presence of medical devices were associated with a high radiation dose above age-specific DRLs in pediatric chest CT, regardless of repositioning before the actual scanning. In addition, off-centering had no clinical impact on radiation dose in the routine practice.
Collapse
|
30
|
Dose reduction in abdominal CT: The road to submillisievert imaging. Eur Radiol 2018; 28:2743-2744. [DOI: 10.1007/s00330-018-5397-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 02/20/2018] [Indexed: 01/01/2023]
|
31
|
Tan SK, Yeong CH, Raja Aman RRA, Ng KH, Abdul Aziz YF, Chee KH, Sun Z. Low tube voltage prospectively ECG-triggered coronary CT angiography: a systematic review of image quality and radiation dose. Br J Radiol 2018; 91:20170874. [PMID: 29493261 DOI: 10.1259/bjr.20170874] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE This study aimed (1) to perform a systematic review on scanning parameters and contrast medium (CM) reduction methods used in prospectively electrocardiography (ECG-triggered low tube voltage coronary CT angiography (CCTA), (2) to compare the achievable dose reduction and image quality and (3) to propose appropriate scanning techniques and CM administration methods. METHODS A systematic search was performed in PubMed, the Cochrane library, CINAHL, Web of Science, ScienceDirect and Scopus, where 20 studies were selected for analysis of scanning parameters and CM reduction methods. RESULTS The mean effective dose (HE) ranged from 0.31 to 2.75 mSv at 80 kVp, 0.69 to 6.29 mSv at 100 kVp and 1.53 to 10.7 mSv at 120 kVp. Radiation dose reductions of 38 to 83% at 80 kVp and 3 to 80% at 100 kVp could be achieved with preserved image quality. Similar vessel contrast enhancement to 120 kVp could be obtained by applying iodine delivery rate (IDR) of 1.35 to 1.45 g s-1 with total iodine dose (TID) of between 10.9 and 16.2 g at 80 kVp and IDR of 1.08 to 1.70 g s-1 with TID of between 18.9 and 20.9 g at 100 kVp. CONCLUSION This systematic review found that radiation doses could be reduced to a rate of 38 to 83% at 80 kVp, and 3 to 80% at 100 kVp without compromising the image quality. Advances in knowledge: The suggested appropriate scanning parameters and CM reduction methods can be used to help users in achieving diagnostic image quality with reduced radiation dose.
Collapse
Affiliation(s)
- Sock Keow Tan
- 1 Department of Biomedical Imaging, Faculty of Medicine, University of Malaya , Kuala Lumpur , Malaysia
| | - Chai Hong Yeong
- 1 Department of Biomedical Imaging, Faculty of Medicine, University of Malaya , Kuala Lumpur , Malaysia
| | | | - Kwan Hoong Ng
- 1 Department of Biomedical Imaging, Faculty of Medicine, University of Malaya , Kuala Lumpur , Malaysia
| | - Yang Faridah Abdul Aziz
- 1 Department of Biomedical Imaging, Faculty of Medicine, University of Malaya , Kuala Lumpur , Malaysia
| | - Kok Han Chee
- 1 Department of Biomedical Imaging, Faculty of Medicine, University of Malaya , Kuala Lumpur , Malaysia.,2 Department of Medicine, Faculty of Medicine, University of Malaya , Kuala Lumpur , Malaysia
| | - Zhonghua Sun
- 3 Department of Medical Radiation Sciences, Curtin University , Perth, WA , Australia
| |
Collapse
|
32
|
Euler A, Obmann MM, Szucs-Farkas Z, Mileto A, Zaehringer C, Falkowski AL, Winkel DJ, Marin D, Stieltjes B, Krauss B, Schindera ST. Comparison of image quality and radiation dose between split-filter dual-energy images and single-energy images in single-source abdominal CT. Eur Radiol 2018; 28:3405-3412. [DOI: 10.1007/s00330-018-5338-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 01/09/2018] [Accepted: 01/17/2018] [Indexed: 12/25/2022]
|
33
|
Attenuation values of renal parenchyma in virtual noncontrast images acquired from multiphase renal dual-energy CT: Comparison with standard noncontrast CT. Eur J Radiol 2018; 101:103-110. [PMID: 29571782 DOI: 10.1016/j.ejrad.2018.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 01/31/2018] [Accepted: 02/03/2018] [Indexed: 11/21/2022]
Abstract
OBJECTIVES To compare the renal parenchyma attenuation of virtual noncontrast (VNC) images derived from multiphase renal dual-energy computed tomography (DECT) with standard noncontrast (SNC) images, and to determine the optimum phase for VNC images. MATERIALS AND METHODS Twenty-nine men and 16 women (mean age, 61 ± 13 years; range, 37-89 years) underwent dynamic renal DECT (100/Sn140 kVp) were included in this institutional review board-approved retrospective study. There were four phases of the scan, which included noncontrast, corticomedullary (CMP), nephrographic (NP), and excretory phases (EP). The VNC images was generated from CMP, NP and EP. CT numbers of SNC images and VNC images of each phases were measured in the renal cortex and medulla. Mean standard deviation of subcutaneous fat was measured as image noise on SNC and VNC images. Radiation dose was recorded and potential radiation dose reduction was estimated. Results were tested for statistical significance using the unpaired t-test and agreement using Bland-Altman plot analysis. RESULTS The difference in mean attenuation between SNC and each phase of VNC images were ≤4 HU. The mean attenuation of renal cortex and medulla was 33.2 ± 4.4 HU, and 34.2 ± 4.8 HU in SNC, 33.6 ± 7.6 HU and 31.1 ± 8.3 HU in VNC of CMP, 34.8 ± 8.6 HU and 35.6 ± 8.5 HU in VNC of NP, 31.5 ± 7.6 HU and 32.4 ± 7.5 HU in VNC of EP. In VNC of CMP, the attenuation of the cortex was higher than the medulla (p < 0.05), and the attenuation of medulla was significant lower than that of SNC (p < 0.01). In VNC of NP, the attenuation of renal cortex was higher than SNC (p < 0.05). In VNC of EP, the attenuation of cortex and medulla were lower than SNC (p < 0.05), and inadequate iodine subtraction in collecting system was noted. Image noise was significantly greater in SNC (p < 0.001). Mean radiation dose reduction achievable by removing the SNC was 12.3% ± 0.9%. CONCLUSIONS VNC images from multiphase renal DECT were similar to SNC images. Using the nephrographic phase can gives more comparable VNC images to SNC images in renal parenchyma than other phases.
Collapse
|
34
|
O'Hora L, Foley S. Iterative reconstruction and automatic tube voltage selection reduce clinical CT radiation doses and image noise. Radiography (Lond) 2018; 24:28-32. [DOI: 10.1016/j.radi.2017.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 08/16/2017] [Accepted: 08/31/2017] [Indexed: 11/24/2022]
|
35
|
Lee HS, Suh YJ, Han K, Kim JY, Chang S, Im DJ, Hong YJ, Lee HJ, Hur J, Kim YJ, Choi BW. Effectiveness of automatic tube potential selection with tube current modulation in coronary CT angiography for obese patients: Comparison with a body mass index-based protocol using the propensity score matching method. PLoS One 2018; 13:e0190584. [PMID: 29304060 PMCID: PMC5755873 DOI: 10.1371/journal.pone.0190584] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 11/21/2017] [Indexed: 01/09/2023] Open
Abstract
Background Reduced image quality from increased X-ray scatter and image noise can be problematic when coronary computed tomography angiography (CCTA) imaging is performed in obese patients. The aim of this study was to compare the image quality and radiation dose obtained using automatic tube potential selection with tube current modulation (APSCM) with those obtained using a body mass index (BMI)-based protocol for CCTA in obese patients. Methods A total of 203 consecutive obese (BMI > 30 kg/m2) patients were retrospectively enrolled, of whom 96 underwent CCTA with APSCM and 107 underwent a BMI-based protocol. After applying the propensity score matching method, the clinical parameters, subjective and objective image quality, and radiation dose were compared between the APSCM group and the matched BMI-based group. These parameters were also compared among different tube potential subgroups. Results No significant differences were observed between the APSCM group and the BMI-based group with respect to image quality or radiation dose assessment (p > 0.05). Twenty patients (21%) examined with 140 kV in the APSCM group were exposed to significantly more radiation (p < 0.05) than patients in the BMI-based group or patients in the other APSCM kV subgroups; significant improvement in image quality was not observed in the 140 kV subgroup. Patients with a high BMI and a large effective diameter tended to be examined with 140 kV (p < 0.05). Conclusion The use of APSCM for CCTA in obese patients did not significantly reduce the radiation dose or improve image quality compared with those in the matched BMI-based group. Our data indicate that it is better to avoid using APSCM when 140 kV is automatically selected, due to increased radiation dose and lack of significant improvement in image quality.
Collapse
Affiliation(s)
- Hong Seon Lee
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Young Joo Suh
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
- * E-mail:
| | - Kyunghwa Han
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Jin Young Kim
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Suyon Chang
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Dong Jin Im
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Yoo Jin Hong
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Hye-Jeong Lee
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Jin Hur
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Young Jin Kim
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Byoung Wook Choi
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| |
Collapse
|
36
|
Variability in Imaging Practices and Comparative Cumulative Effective Dose for Neuroblastoma and Nephroblastoma Patients at 6 Pediatric Oncology Centers. J Pediatr Hematol Oncol 2018; 40:36-42. [PMID: 28697171 DOI: 10.1097/mph.0000000000000915] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The purpose of this study was to estimate the cumulative effective dose (CED) from diagnosis and posttherapy computed tomographic (CT) scans performed on children treated for neuroblastoma or nephroblastoma (Wilms tumor) and to examine the different imaging practices used in 6 regional pediatric oncology centers between January 2010 and December 2013. We analyzed retrospectively the CT scan acquisition data in children aged 10 years or younger at diagnosis. The use of nonionizing imaging modalities was reported. The CT examinations of 129 children, with a mean age at diagnosis of 36 months, treated for 66 neuroblastomas and 63 nephroblastomas, were analyzed. The mean follow-up period was 28 months (minimum, 8 months, maximum, 41 mo). There were 600 CT scans, with a total of 1039 acquisitions. The mean CED from CT scans was 27 mSv (minimum=18.25, maximum=45). Abdominal CT examinations contributed 85% of the total CED. A median of 4.6 CT scans, 10.3 sonograms, and 0.4 magnetic resonance imaging examinations per child were performed. Our results suggest a reduction in radiation exposure but variability in the imaging modality choice and acquisition protocols. We emphasize the need for consensus and standardization in oncologic pediatric imaging procedures. When feasible, we encourage the substitution of nonionizing examinations for CT.
Collapse
|
37
|
Sarmento S, Mendes B, Gouvêa M. Automatic calculation of patient size metrics in computed tomography: What level of computational accuracy do we need? J Appl Clin Med Phys 2017; 19:218-227. [PMID: 29265700 PMCID: PMC5768030 DOI: 10.1002/acm2.12240] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 11/04/2017] [Accepted: 11/14/2017] [Indexed: 12/04/2022] Open
Abstract
Objectives To compare the effectiveness of two different patient size metrics based on water equivalent diameter (Dw), the mid‐scan water equivalent diameter Dw_c, and the mean (average) water equivalent diameter in the imaged region, Dw_ave, for automatic detection of accidental changes in computed tomography (CT) acquisition protocols. Methods Patient biometric data (height and weight) were available from a previous survey for 80 adult chest examinations, and 119 adult single‐acquisition chest–abdomen–pelvis (CAP) examinations for two 16 slice scanners (GE LightSpeed and Toshiba Aquilion RXL) equipped with automatic tube current modulation (ATCM). Dw_c and Dw_ave were calculated from the archived CT images. Size‐specific dose estimates (SSDE) were obtained from volume CT dose index (CTDIvol), using the conversion factors for a patient diameter of Dw_c. Results CTDIvol and SSDE correlate better with Dw_ave than with Dw_c. R‐squared values of linear fits to CTDIvol of CAP examinations were 0.81–0.89 for Dw_c and 0.93–0.94 for Dw_ave (SSDE: 0.69–080 for Dw_c, 0.87–0.92 for Dw_ave). Percentage differences between Dw_c and Dw_ave were −4 ± 4% for chest and +5 ± 4% for CAP examinations (in % of Dw_ave). However, small Dw variations translated as larger variations in CTDIvol for these ATCM systems (e.g., a 24% increase in Dw doubled CTDIvol). The dependence of CTDIvol on Dw_ave was similar for chest and CAP examinations performed with similar ATCM parameters, while use of Dw_c resulted in a clear separation of the same data according to examination type. Maximum Dw variation in the imaged region was 5.6 ± 1.6 cm for chest and 6.5 ± 1.4 cm for CAP examinations. Conclusions Dw_ave is a better metric than Dw_c for binning similar‐sized patients in dose comparison studies, despite the additional computational effort required for its calculation Therefore, when implementing automatic determination of Dw for SSDE calculations, automatic calculation of Dw_ave should be considered.
Collapse
Affiliation(s)
- Sandra Sarmento
- Medical Physics, Radiobiology and Radiation Protection Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Medical Physics Department, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Bruno Mendes
- Medical Physics, Radiobiology and Radiation Protection Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Medical Physics Department, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Margarida Gouvêa
- Radiology Department, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| |
Collapse
|
38
|
Body composition determinants of radiation dose during abdominopelvic CT. Insights Imaging 2017; 9:9-16. [PMID: 29063481 PMCID: PMC5825306 DOI: 10.1007/s13244-017-0577-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 09/04/2017] [Accepted: 09/25/2017] [Indexed: 11/13/2022] Open
Abstract
Objectives We designed a prospective study to investigate the in-vivo relationship between abdominal body composition and radiation exposure to determine the strongest body composition predictor of dose length product (DLP) at CT. Methods Following institutional review board approval, quantitative analysis was performed prospectively on 239 consecutive patients who underwent abdominopelvic CT. DLP, BMI, volumes of abdominal adipose tissue, muscle, bone and solid organs were recorded. Results All measured body composition parameters correlated positively with DLP. Linear regression (R2 = 0.77) revealed that total adipose volume was the strongest predictor of radiation exposure [B (95% CI) = 0.027(0.024–0.030), t=23.068, p < 0.001]. Stepwise linear regression using DLP as the dependent and BMI and total adipose tissue as independent variables demonstrated that total adipose tissue is more predictive of DLP than BMI [B (95% CI) = 16.045 (11.337-20.752), t=6.681, p < 0.001]. Conclusions The volume of adipose tissue was the strongest predictor of radiation exposure in our cohort. Main message • Individual body composition variables correlate with DLP at abdominopelvic CT. • Total abdominal adipose tissue is the strongest predictor of radiation exposure. • Muscle volume is also a significant but weaker predictor of DLP.
Collapse
|
39
|
Masuda T, Funama Y, Kiguchi M, Imada N, Oku T, Sato T, Awai K. Radiation dose reduction based on CNR index with low-tube voltage scan for pediatric CT scan: experimental study using anthropomorphic phantoms. SPRINGERPLUS 2016; 5:2064. [PMID: 27995041 PMCID: PMC5133217 DOI: 10.1186/s40064-016-3715-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 11/21/2016] [Indexed: 12/13/2022]
Abstract
Background To figure out the relationship between image noise and contrast noise ratio (CNR) at different tube voltages, using anthropomorphic new-born and 1-year-old phantoms, and to discuss the feasibility of radiation dose reduction, based on the obtained CNR index from image noise. We performed helical scans of the anthropomorphic new-born and 1-year-old phantoms. The CT numbers of the simulated aorta and image noise of the simulated mediastinum were measured; then CNR was calculated on 80, 100, and 120-kVp images reconstructed with filtered back projection (FBP) and iterative reconstruction (IR). We also measured the center and surface dose in the case of CNR of 14 using radio-photoluminescence glass dosimeters. Results The CT number of the simulated aorta was increased with decreasing tube voltage from 120 to 80 kVp (362.5–535.1 HU for the new-born, 358.9–532.6 HU for the 1-year-old). At CNR of 14, the center dose was 0.4, 0.6 and 0.9 mGy at FBP and 0.5, 0.6 and 0.9 mGy at IR and with the new-born phantom acquired at 80, 100 and 120 kVp, respectively. The center dose for FBP image was reduced by 56% at 80 kVp, 34% at 100 kVp for the new-born and 36% at 80 kVp, 22% at 100 kVp for the 1-year-old compared with that at 120 kVp. We obtained a relationship between image noise and CNR at different tube voltages using the anthropomorphic new-born and 1-year-old phantoms. Conclusion The use of index of CNR with low-tube voltage may achieve further radiation dose reduction in pediatric CT examination.
Collapse
Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima, 730-8655 Japan ; Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Masao Kiguchi
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Naoyuki Imada
- Department of Radiological Technology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima, 730-8655 Japan
| | - Takayuki Oku
- Department of Radiological Technology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima, 730-8655 Japan
| | - Tomoyasu Sato
- Department of Diagnostic Radiology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima, 730-8655 Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| |
Collapse
|
40
|
Martin CJ, Sookpeng S. Setting up computed tomography automatic tube current modulation systems. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2016; 36:R74-R95. [PMID: 27485613 DOI: 10.1088/0952-4746/36/3/r74] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Automatic tube current modulation (ATCM) on CT scanners can yield significant reductions in patient doses. Modulation is based on x-ray beam attenuation in body tissues obtained from scan projection radiographs (SPRs) and aims to maintain the same level of image quality throughout a scan. Noise level is important in judging image quality, but tissues in larger patients exhibit higher contrast resulting from the presence of fat. CT scanner manufacturers use different metrics to assess image quality. Some employ a simple measure of image noise, while others adopt a measure related to a reference image that accepts higher noise levels in more attenuating parts with higher contrast. At the present time there is no standard method for testing ATCM. This paper reviews the operation of different ATCM systems, considers options for testing, and sets out a framework that could be used for optimizing clinical protocols. If dose and image quality can be established for a reference phantom, the modulation performed by ATCM systems can be characterised using anatomical phantoms or geometrical elliptical phantoms which may be conical or include sections of varying dimension. For scanners using a reference image or mAs, selection of the image quality reference determines other factors. However, for scanners using a noise reference, a higher noise level should be selected for larger patients to avoid high doses, and the operator should ensure that appropriate limits are set for mA modulation. Other factors that need to be considered include the SPRs used to plan the ATCM and image thickness. Users should be aware of the mode of operation of the ATCM system on their CT scanner, and be familiar with the effects of changing different protocol parameters. The behaviour of ATCM systems should be established through testing of each CT scanner with suitable phantoms during commissioning.
Collapse
Affiliation(s)
- C J Martin
- Health Physics, Department of Clinical Physics, University of Glasgow, Gartnavel Royal Hospital, Glasgow, G12 0XH, UK
| | | |
Collapse
|
41
|
Kalra MK, Sodickson AD, Mayo-Smith WW. CT Radiation: Key Concepts for Gentle and Wise Use. Radiographics 2016; 35:1706-21. [PMID: 26466180 DOI: 10.1148/rg.2015150118] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Use of computed tomography (CT) in medicine comes with the responsibility of its appropriate (wise) and safe (gentle) application to obtain required diagnostic information with the lowest possible dose of radiation. CT provides useful information that may not be available with other imaging modalities in many clinical situations in children and adults. Inappropriate or excessive use of CT should be avoided, especially if required information can be obtained in an accurate and time-efficient manner with other modalities that require a lower radiation dose, or non-radiation-based imaging modalities such as ultrasonography and magnetic resonance imaging. In addition to appropriate use of CT, the radiology community also must monitor scanning practices and protocols. When appropriate, high-contrast regions and lesions should be scanned with reduced dose, but overly zealous dose reduction should be avoided for assessment of low-contrast lesions. Patients' cross-sectional body size should be taken into account to deliver lower radiation dose to smaller patients and children. Wise use of CT scanning with gentle application of radiation dose can help maximize the diagnostic value of CT, as well as address concerns about potential risks of radiation. In this article, key concepts in CT radiation dose are reviewed, including CT dose descriptors; radiation doses from CT procedures; and factors and technologies that affect radiation dose and image quality, including their use in creating dose-saving protocols. Also discussed are the contributions of radiation awareness campaigns such as the Image Gently and Image Wisely campaigns and the American College of Radiology Dose Index Registry initiatives.
Collapse
Affiliation(s)
- Mannudeep K Kalra
- From the Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Mass (M.K.K.); and Department of Radiology, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115 and Harvard Medical School, Boston, Mass (A.D.S., W.W.M.S.)
| | - Aaron D Sodickson
- From the Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Mass (M.K.K.); and Department of Radiology, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115 and Harvard Medical School, Boston, Mass (A.D.S., W.W.M.S.)
| | - William W Mayo-Smith
- From the Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Mass (M.K.K.); and Department of Radiology, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115 and Harvard Medical School, Boston, Mass (A.D.S., W.W.M.S.)
| |
Collapse
|
42
|
Lv P, Liu J, Chai Y, Yan X, Gao J, Dong J. Automatic spectral imaging protocol selection and iterative reconstruction in abdominal CT with reduced contrast agent dose: initial experience. Eur Radiol 2016; 27:374-383. [PMID: 27097790 DOI: 10.1007/s00330-016-4349-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 03/21/2016] [Accepted: 03/29/2016] [Indexed: 01/10/2023]
Abstract
OBJECTIVE To evaluate the feasibility, image quality, and radiation dose of automatic spectral imaging protocol selection (ASIS) and adaptive statistical iterative reconstruction (ASIR) with reduced contrast agent dose in abdominal multiphase CT. METHODS One hundred and sixty patients were randomly divided into two scan protocols (n = 80 each; protocol A, 120 kVp/450 mgI/kg, filtered back projection algorithm (FBP); protocol B, spectral CT imaging with ASIS and 40 to 70 keV monochromatic images generated per 300 mgI/kg, ASIR algorithm. Quantitative parameters (image noise and contrast-to-noise ratios [CNRs]) and qualitative visual parameters (image noise, small structures, organ enhancement, and overall image quality) were compared. RESULTS Monochromatic images at 50 keV and 60 keV provided similar or lower image noise, but higher contrast and overall image quality as compared with 120-kVp images. Despite the higher image noise, 40-keV images showed similar overall image quality compared to 120-kVp images. Radiation dose did not differ between the two protocols, while contrast agent dose in protocol B was reduced by 33 %. CONCLUSION Application of ASIR and ASIS to monochromatic imaging from 40 to 60 keV allowed contrast agent dose reduction with adequate image quality and without increasing radiation dose compared to 120 kVp with FBP. KEY POINTS • Automatic spectral imaging protocol selection provides appropriate scan protocols. • Abdominal CT is feasible using spectral imaging and 300 mgI/kg contrast agent. • 50-keV monochromatic images with 50 % ASIR provide optimal image quality.
Collapse
Affiliation(s)
- Peijie Lv
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1, East Jianshe Road, Zhengzhou, Henan Province, China, 450052
| | - Jie Liu
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1, East Jianshe Road, Zhengzhou, Henan Province, China, 450052
| | - Yaru Chai
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1, East Jianshe Road, Zhengzhou, Henan Province, China, 450052
| | - Xiaopeng Yan
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1, East Jianshe Road, Zhengzhou, Henan Province, China, 450052
| | - Jianbo Gao
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1, East Jianshe Road, Zhengzhou, Henan Province, China, 450052.
| | - Junqiang Dong
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, No.1, East Jianshe Road, Zhengzhou, Henan Province, China, 450052
| |
Collapse
|
43
|
Durmus T, Luhur R, Daqqaq T, Schwenke C, Knobloch G, Huppertz A, Hamm B, Lembcke A. Individual selection of X-ray tube settings in computed tomography coronary angiography: Reliability of an automated software algorithm to maintain constant image quality. Eur J Radiol 2016; 85:963-71. [PMID: 27130057 DOI: 10.1016/j.ejrad.2016.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 02/28/2016] [Accepted: 03/02/2016] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To evaluate a software tool that claims to maintain a constant contrast-to-noise ratio (CNR) in high-pitch dual-source computed tomography coronary angiography (CTCA) by automatically selecting both X-ray tube voltage and current. METHODS A total of 302 patients (171 males; age 61±12years; body weight 82±17kg, body mass index 27.3±4.6kg/cm(2)) underwent CTCA with a topogram-based, automatic selection of both tube voltage and current using dedicated software with quality reference values of 100kV and 250mAs/rotation (i.e., standard values for an average adult weighing 75kg) and an injected iodine load of 222mg/kg. RESULTS The average radiation dose was estimated to be 1.02±0.64mSv. All data sets had adequate contrast enhancement. Average CNR in the aortic root, left ventricle, and left and right coronary artery was 15.7±4.5, 8.3±2.9, 16.1±4.3 and 15.3±3.9 respectively. Individual CNR values were independent of patients' body size and radiation dose. However, individual CNR values may vary considerably between subjects as reflected by interquartile ranges of 12.6-18.6, 6.2-9.9, 12.8-18.9 and 12.5-17.9 respectively. Moreover, average CNR values were significantly lower in males than females (15.1±4.1 vs. 16.6±11.7 and 7.9±2.7 vs. 8.9±3.0, 15.5±3.9 vs. 16.9±4.6 and 14.7±3.6 vs. 16.0±4.1 respectively). CONCLUSION A topogram-based automatic selection of X-ray tube settings in CTCA provides diagnostic image quality independent of patients' body size. Nevertheless, considerable variation of individual CNR values between patients and significant differences of CNR values between males and females occur which questions the reliability of this approach.
Collapse
Affiliation(s)
- Tahir Durmus
- Department of Radiology, Charité-Universitätsmedizin Berlin, Charité Campus Mitte, Berlin, Germany.
| | - Reny Luhur
- Department of Radiology, Charité-Universitätsmedizin Berlin, Charité Campus Mitte, Berlin, Germany
| | - Tareef Daqqaq
- Department of Radiology, Charité-Universitätsmedizin Berlin, Charité Campus Mitte, Berlin, Germany
| | | | - Gesine Knobloch
- Department of Radiology, Charité-Universitätsmedizin Berlin, Charité Campus Mitte, Berlin, Germany
| | | | - Bernd Hamm
- Department of Radiology, Charité-Universitätsmedizin Berlin, Charité Campus Mitte, Berlin, Germany
| | - Alexander Lembcke
- Department of Radiology, Charité-Universitätsmedizin Berlin, Charité Campus Mitte, Berlin, Germany
| |
Collapse
|
44
|
Synergistic Radiation Dose Reduction by Combining Automatic Tube Voltage Selection and Iterative Reconstruction. J Thorac Imaging 2016; 31:111-8. [DOI: 10.1097/rti.0000000000000196] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
45
|
Filev PD, Mittal PK, Tang X, Duong PA, Wang X, Small WC, Applegate K, Moreno CC. Increased Computed Tomography Dose Due to Miscentering With Use of Automated Tube Voltage Selection: Phantom and Patient Study. Curr Probl Diagn Radiol 2015; 45:265-70. [PMID: 26810714 DOI: 10.1067/j.cpradiol.2015.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 11/08/2015] [Indexed: 11/22/2022]
Abstract
The purpose of the article is to determine if miscentering affected dose with use of automated tube voltage selection software. An anthropomorphic phantom was imaged at different table heights (centered in the computed tomography [CT] gantry, and -6, -3, +3, and +5.7cm relative to the centered position). Topogram magnification, tube voltage selection, and dose were assessed. Effect of table height on dose also was assessed retrospectively in human subjects (n = 50). When the CT table was positioned closer to the x-ray source, subjects appeared up to 33% magnified in topogram images. When subjects appeared magnified in topogram images, automated software selected higher tube potentials and tube currents that were based on the magnified size of the subject rather than the subject׳s true size. Table height strongly correlated with CT dose index (r = 0.98, P < 0.05) and dose length product (r = 0.98, P < 0.05) in the phantom study. Transverse dimension in the topogram highly correlated with dose in human subjects (r = 0.75-0.87, P <0.05). Miscentering results in increased dose due to topogram magnification with automated voltage selection software.
Collapse
Affiliation(s)
- Peter D Filev
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA
| | - Pardeep K Mittal
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA
| | - Xiangyang Tang
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA
| | - Phuong-Anh Duong
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA
| | - Xiaojing Wang
- Biostatistics Shared Core Resource at Winship Cancer Institute, Atlanta, GA
| | - William C Small
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA
| | - Kimberly Applegate
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA
| | - Courtney C Moreno
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA.
| |
Collapse
|
46
|
Automated tube voltage selection in thoracoabdominal computed tomography at high pitch using a third-generation dual-source scanner: image quality and radiation dose performance. Invest Radiol 2015; 50:352-60. [PMID: 25591129 DOI: 10.1097/rli.0000000000000133] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVES The objective of this study was to evaluate the radiation dose and image quality performance of thoracoabdominal examinations with an automated tube voltage selection (tube voltage adaptation), tube current modulation, and high pitch using a third-generation dual-source computed tomography (CT) compared intraindividually with 120-kV examinations with tube current modulation with special attention on clinically relevant lesions in the liver, the lungs, and extrahepatic soft tissues. MATERIALS AND METHODS This study was approved by the institutional review board. Computed tomography of the body was performed using a third-generation dual-source system in 95 patients (mean body mass index, 25 kg/m²; range, 18-35 kg/m²). For 49 of these patients, all calculated tube settings and resulting dose values were recorded for each of the 12 gradual contrast weightings of the tube voltage adaptation algorithm. Spiral CT was performed for all patients with an intermediate weighting (grade 7) in a portal venous phase at 120 reference kV, 180 reference mAs, and pitch of 1.55. Objective image quality was assessed on the basis of contrast-to-noise ratio. Subjective image quality was assessed on the basis of clarity and sharpness of anatomical and pathological structures as well as interfering beam hardening and spiral and motion artifacts (heart, lungs, diaphragm). Previous examinations on a 64-slice scanner served as reference. RESULTS All examinations were rated good or excellent for clinical diagnosis. Automated tube voltage selection resulted in significantly lower effective radiation dose (9.5 mSv) compared with the reference (12.0 mSv; P < 0.01). Contrast-to-noise ratio and image quality of soft tissue lesions were significantly increased (P < 0.01). Motion artifacts were significantly reduced (P < 0.01). CONCLUSIONS Automated tube voltage adaptation combined with high-pitch protocols allows for a substantial radiation dose reduction while substantially increasing the image quality, even at large-volume exposure.
Collapse
|
47
|
Oliveri A, Howarth N, Gevenois PA, Tack D. Short- and long-term effects of clinical audits on compliance with procedures in CT scanning. Eur Radiol 2015; 26:2663-8. [PMID: 26577376 DOI: 10.1007/s00330-015-4100-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 10/28/2015] [Accepted: 10/29/2015] [Indexed: 01/06/2023]
Abstract
PURPOSE To test the hypothesis that quality clinical audits improve compliance with the procedures in computed tomography (CT) scanning. MATERIALS AND METHODS This retrospective study was conducted in two hospitals, based on 6950 examinations and four procedures, focusing on the acquisition length in lumbar spine CT, the default tube current applied in abdominal un-enhanced CT, the tube potential selection for portal phase abdominal CT and the use of a specific "paediatric brain CT" procedure. The first clinical audit reported compliance with these procedures. After presenting the results to the stakeholders, a second audit was conducted to measure the impact of this information on compliance and was repeated the next year. Comparisons of proportions were performed using the Chi-square Pearson test. RESULTS Depending on the procedure, the compliance rate ranged from 27 to 88 % during the first audit. After presentation of the audit results to the stakeholders, the compliance rate ranged from 68 to 93 % and was significantly improved for all procedures (P ranging from <0.001 to 0.031) in both hospitals and remained unchanged during the third audit (P ranging from 0.114 to 0.999). CONCLUSION Quality improvement through repeated compliance audits with CT procedures durably improves this compliance. KEY POINTS • Compliance with CT procedures is operator-dependent and not perfect. • Compliance differs between procedures and hospitals, even within a unified department. • Compliance is improved through audits followed by communication to the stakeholders. • This improvement is sustainable over a one-year period.
Collapse
Affiliation(s)
- Antonio Oliveri
- Université libre de Bruxelles, School of Medicine, Route de Lennik 808, 1070, Brussels, Belgium
| | - Nigel Howarth
- Department of Radiology, Clinique des Grangettes, 7 Chemin des Grangettes, 1224, Chêne-Bougeries, Switzerland
| | - Pierre Alain Gevenois
- Department of Radiology, Hôpital Erasme, Route de Lennik 808, 1070, Brussels, Belgium
| | - Denis Tack
- Department of Radiology, EpiCURA, Clinique Louis Caty, rue Louis Caty 136, 7331, Baudour, Belgium.
| |
Collapse
|
48
|
Santos J, Foley S, Paulo G, McEntee MF, Rainford L. The impact of pediatric-specific dose modulation curves on radiation dose and image quality in head computed tomography. Pediatr Radiol 2015; 45:1814-22. [PMID: 26242810 DOI: 10.1007/s00247-015-3398-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 03/28/2015] [Accepted: 06/01/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND The volume of CT examinations has increased with resultant increases in collective dose values over the last decade. OBJECTIVE To analyze the impact of the tube current and voltage modulation for dose values and image quality of pediatric head CT examinations. MATERIALS AND METHODS Head CT examinations were performed on anthropomorphic phantoms and four pediatric age categories before and after the introduction of dedicated pediatric curves for tube voltage and current modulation. Local diagnostic reference levels were calculated. Visual grading characteristic image quality evaluation was performed by four pediatric neuroradiologists and image noise comparisons were performed. RESULTS Pediatric-specific modulation curves demonstrated a 49% decrease in mean radiation dose for phantom examinations. The local diagnostic reference levels (CTDIvol) for clinical examinations decreased by 52%, 41%, 46% and 40% for newborn, 5-, 10- and 15-year-old patients, respectively. Visual grading characteristic image quality was maintained for the majority of age categorizations (area under the curve = 0.5) and image noise measurements did not change (P = 0.693). CONCLUSION Pediatric-specific dose modulation curves resulted in an overall mean dose reduction of 45% with no significant differences in subjective or objective image quality findings.
Collapse
Affiliation(s)
- Joana Santos
- Instituto Politécnico de Coimbra, ESTESC, DMIR, Rua 5 de Outubro, S. Martinho do Bispo, 3046-854, Coimbra, Portugal.
| | - Shane Foley
- School of Medicine & Medical Science, Health Science Centre, University College Dublin, Belfield, Dublin 4, Ireland
| | - Graciano Paulo
- Instituto Politécnico de Coimbra, ESTESC, DMIR, Rua 5 de Outubro, S. Martinho do Bispo, 3046-854, Coimbra, Portugal
| | - Mark F McEntee
- Faculty of Health Sciences, Cumberland Campus, The University of Sydney, Sydney, Australia
| | - Louise Rainford
- School of Medicine & Medical Science, Health Science Centre, University College Dublin, Belfield, Dublin 4, Ireland
| |
Collapse
|
49
|
Low contrast detectability performance of model observers based on CT phantom images: kVp influence. Phys Med 2015; 31:798-807. [DOI: 10.1016/j.ejmp.2015.04.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 03/16/2015] [Accepted: 04/18/2015] [Indexed: 11/18/2022] Open
|
50
|
Estimated Patient Dose Indexes in Adult and Pediatric MDCT: Comparison of Automatic Tube Voltage Selection With Fixed Tube Current, Fixed Tube Voltage, and Weight-Based Protocols. AJR Am J Roentgenol 2015; 205:592-8. [DOI: 10.2214/ajr.14.13242] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|