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Safari A, Mahdavi M, Fardid R, Oveisi A, Jalli R, Haghani M. Evaluation of hafnium oxide nanoparticles imaging characteristics as a contrast agent in X-ray computed tomography. Radiol Phys Technol 2024; 17:441-450. [PMID: 38630390 DOI: 10.1007/s12194-024-00797-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 05/27/2024]
Abstract
This research aimed to compare the quantitative imaging attributes of synthesized hafnium oxide nanoparticles (NPs) derived from UiO-66-NH2(Hf) and two gadolinium- and iodine-based clinical contrast agents (CAs) using cylindrical phantom. Aqueous solutions of the studied CAs, containing 2.5, 5, and 10 mg/mL of HfO2NPs, gadolinium, and iodine, were prepared. Constructed within a cylindrical phantom, 15 cc small tubes were filled with CAs. Maintaining constant mAs, the phantom underwent scanning at tube voltage variations from 80 to 140 kVp. The CT numbers were quantified in Hounsfield units (HU), and the contrast-to-noise ratios (CNR) were calculated within delineated regions of interest (ROI) for all CAs. The HfO2NPs at 140 kVp and concentration of 2.5 mg/ml exhibited 2.3- and 1.3-times higher CT numbers than iodine and gadolinium, respectively. Notably, gadolinium consistently displayed higher CT numbers than iodine across all exposure techniques and concentrations. At the highest tube potential, the maximum amount of the CAs CT numbers was attained, and at 140 kVp and concentration of 2.5 mg/ml of HfO2NPs the CNR surpassed iodine by 114%, and gadolinium by 30%, respectively. HfO2NPs, as a contrast agent, demonstrated superior image quality in terms of contrast and noise in comparison to iodine- and gadolinium-based contrast media, particularly at higher energies of X-ray in computed tomography. Thus, its utilization is highly recommended in CT.
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Affiliation(s)
- Arash Safari
- Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.
- Department of Radiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.
| | - Maziyar Mahdavi
- Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Radiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Reza Fardid
- Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Radiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Alireza Oveisi
- Department of Chemistry, Faculty of Sciences, University of Zabol, P.O. Box: 98615-538, Zabol, Iran.
| | - Reza Jalli
- Department of Radiology, Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Masoud Haghani
- Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.
- Department of Radiology, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.
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Long M, Albeshan S, Alashban Y, England A, Moore N, Young R, Bezzina P, McEntee MF. The effect of contact radiation shielding on breast dose during CT abdomen-pelvis: a phantom study. RADIATION PROTECTION DOSIMETRY 2023; 199:2104-2111. [PMID: 37551012 DOI: 10.1093/rpd/ncad218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 07/05/2023] [Accepted: 07/09/2023] [Indexed: 08/09/2023]
Abstract
This study aims to investigate if contact shielding reduces breast radiation dose during computed tomography (CT) abdomen-pelvis examinations using automatic tube current modulation to protect one of the four most radiosensitive organs during CT examinations. Dose measurements were taken with and without contact shielding across the anterior and lateral aspects of the breasts and with and without organ dose modulation (ODM) to quantify achievable dose reductions. Although there are no statistically significant findings, when comparing with and without shielding, the mean breast surface dose was reduced by 0.01 μSv without ODM (1.92-1.91 μSv, p = 0.49) and increased by 0.03 μSv with ODM (1.53-1.56 μSv, p = 0.44). Comparing with and without ODM, the mean breast surface dose was reduced by 0.35 μSv with shielding (1.91-1.56 μSv, p = 0.24) and by 0.39 μSv without shielding (1.92-1.53 μSv, p = 0.17). The addition of contact shielding does not provide significant breast surface radiation dose reduction during CT abdomen-pelvis.
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Affiliation(s)
- Maria Long
- Medical Imaging and Radiation Therapy Department, School of Medicine, UG Assert, Brookfield Health Sciences, University College Cork, Cork T12 AK54, Ireland
| | - Salman Albeshan
- Radiological Sciences Department, College of Applied Medical Sciences, King Saud University, PO Box 145111, Riyadh 4545, Saudi Arabia
| | - Yazeed Alashban
- Radiological Sciences Department, College of Applied Medical Sciences, King Saud University, PO Box 145111, Riyadh 4545, Saudi Arabia
| | - Andrew England
- Medical Imaging and Radiation Therapy Department, School of Medicine, UG Assert, Brookfield Health Sciences, University College Cork, Cork T12 AK54, Ireland
| | - Niamh Moore
- Medical Imaging and Radiation Therapy Department, School of Medicine, UG Assert, Brookfield Health Sciences, University College Cork, Cork T12 AK54, Ireland
| | - Rena Young
- Medical Imaging and Radiation Therapy Department, School of Medicine, UG Assert, Brookfield Health Sciences, University College Cork, Cork T12 AK54, Ireland
| | - Paul Bezzina
- Department of Radiography, Faculty of Health Sciences, University of Malta, Msida MSD 2080, Malta
| | - Mark F McEntee
- Medical Imaging and Radiation Therapy Department, School of Medicine, UG Assert, Brookfield Health Sciences, University College Cork, Cork T12 AK54, Ireland
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Akyea-Larbi KO, Tetteh MA, Martinsen ACT, Hasford F, Inkoom S, Jensen K. BENCHMARKING OF A NEW AUTOMATIC CT RADIATION DOSE CALCULATOR. RADIATION PROTECTION DOSIMETRY 2020; 191:361-368. [PMID: 33151301 DOI: 10.1093/rpd/ncaa167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 09/03/2020] [Accepted: 09/23/2020] [Indexed: 06/11/2023]
Abstract
Information on patient radiation dose is essential to meet the radiation protection regulations and the demands of dose optimization. Vendors have developed different tools for patient dose assessment for radiological purposes. In this study, estimated effective doses derived from a new image-based software tool (DoseWatch, GE Healthcare) was benchmarked against the corresponding doses from a dose calculator (CT-Expo, SASCRAD) and a conversion coefficient method. Dose data from 150 adult patients (66 male and 84 female), who underwent CT head, abdominopelvic or chest examinations, were retrospectively collected using DoseWatch. Effective dose estimated by DoseWatch was significantly lower than that of CT-Expo and DLP-E (k) (p ≤ 0.001). For the organ doses, DoseWatch resulted in lower dose than CT-Expo for all the organs with the exception of testis (p ≤ 001) and eye lenses (p ≤ 0.026).
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Affiliation(s)
- Kofi Okyere Akyea-Larbi
- Department of Medical Physics, School of Nuclear and Allied Sciences, University of Ghana, LG 25 Legon, Accra, Ghana
- Department of Physics, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway
| | - Mercy Afadzi Tetteh
- Department of Physics, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway
- Department of Diagnostic Physics, Oslo University Hospital, 0424 Oslo, Norway
| | - Anne Catrine T Martinsen
- Department of Diagnostic Physics, Oslo University Hospital, 0424 Oslo, Norway
- Faculty of Health sciences, Oslo Metropolitan University, N-0130 Oslo, Norway
| | - Francis Hasford
- Department of Medical Physics, School of Nuclear and Allied Sciences, University of Ghana, LG 25 Legon, Accra, Ghana
- Radiological and Medical Sciences Research Institute, Ghana Atomic Energy Commission, LG 80 Legon, Accra, Ghana
| | - Stephen Inkoom
- Department of Medical Physics, School of Nuclear and Allied Sciences, University of Ghana, LG 25 Legon, Accra, Ghana
- Radiation Protection Institute, Ghana Atomic Energy Commission, LG 80 Legon, Accra, Ghana
| | - Kristin Jensen
- Department of Diagnostic Physics, Oslo University Hospital, 0424 Oslo, Norway
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Automated Segmentation of the Craniofacial Skeleton With "Black Bone" Magnetic Resonance Imaging. J Craniofac Surg 2020; 31:1015-1017. [PMID: 32503096 DOI: 10.1097/scs.0000000000006552] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Three-dimensional (3D) imaging of the craniofacial skeleton is integral in managing a wide range of bony pathologies. The authors have previously demonstrated the potential of "Black Bone" MRI (BB) as a non-ionizing alternative to CT. However, even in experienced hands 3D rendering of BB datasets can be challenging and time consuming. The objectives of this study were to develop and test a semi- and fully-automated segmentation algorithm for the craniofacial skeleton.Previously acquired adult volunteer (n = 15) BB datasets of the head were utilized. Imaging was initially 3D rendered with our conventional manual technique. An algorithm to remove the outer soft-tissue envelope was developed and 3D rendering completed with the processed datasets (semi-automated). Finally, a fully automated 3D-rendering method was developed and applied to the datasets. All 3D rendering was completed with Fovia High Definition Volume Rendering (Fovia Inc, Palo Alto, CA). Analysis was undertaken of the 3D visual results and the time taken for data processing and interactive manipulation.The mean time for manual segmentation was 12.8 minutes, 3.1 minutes for the semi-automated algorithm, and 0 minutes for the fully automated algorithm. Further fine adjustment was undertaken to enhance the automated segmentation results, taking a mean time of 1.4 minutes.Automated segmentation demonstrates considerable potential, offering significant time saving in the production of 3D BB imaging in adult volunteers. the authors continue to undertake further development of our segmentation algorithms to permit adaption to the pediatric population in whom non-ionizing imaging confers the most potential benefit.
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Aulino JM, Kirsch CFE, Burns J, Busse PM, Chakraborty S, Choudhri AF, Conley DB, Jones CU, Lee RK, Luttrull MD, Moritani T, Policeni B, Ryan ME, Shah LM, Sharma A, Shih RY, Subramaniam RM, Symko SC, Bykowski J. ACR Appropriateness Criteria ® Neck Mass-Adenopathy. J Am Coll Radiol 2020; 16:S150-S160. [PMID: 31054741 DOI: 10.1016/j.jacr.2019.02.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 02/08/2019] [Indexed: 11/26/2022]
Abstract
A palpable neck mass may be the result of neoplastic, congenital, or inflammatory disease. Older age suggests neoplasia, and a congenital etiology is more prevalent in the pediatric population. The imaging approach is based on the patient age, mass location, and clinical pulsatility. Underlying human papillomavirus-related malignancy should be considered in all age groups. Although the imaging appearance of some processes in the head and neck overlap, choosing the appropriate imaging examination may allow a specific diagnosis, or a limited differential diagnosis. Tissue sampling is indicated to confirm suspected malignancy. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.
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Affiliation(s)
| | | | - Claudia F E Kirsch
- Panel Chair, Northwell Health, Zucker Hofstra School of Medicine at Northwell, Manhasset, New York
| | | | - Paul M Busse
- Massachusetts General Hospital, Boston, Massachusetts
| | - Santanu Chakraborty
- Ottawa Hospital Research Institute and the Department of Radiology, The University of Ottawa, Ottawa, Ontario, Canada, Canadian Association of Radiologists
| | - Asim F Choudhri
- Le Bonheur Children's Hospital, University of Tennessee Health Science Center, Memphis, Tennessee
| | - David B Conley
- Northwestern University Feinberg School of Medicine, Chicago, Illinois, American Academy of Otolaryngology-Head and Neck Surgery
| | | | - Ryan K Lee
- Einstein Healthcare Network, Philadelphia, Pennsylvania
| | | | | | - Bruno Policeni
- University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Maura E Ryan
- Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | | | - Aseem Sharma
- Mallinckrodt Institute of Radiology, Saint Louis, Missouri
| | - Robert Y Shih
- Walter Reed National Military Medical Center, Bethesda, Maryland
| | | | | | - Julie Bykowski
- Specialty Chair, UC San Diego Health Center, San Diego, California
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Poehler GH, Alikhani B, Klimes F, Hauck EF, Ringe KI, Sonnow L, Wacker F, Raatschen HJ. Impact of active dose management on radiation exposure and image quality in computed tomography: An observational study in 1315 patients. Eur J Radiol 2020; 125:108900. [DOI: 10.1016/j.ejrad.2020.108900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 11/17/2022]
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Suntharalingam S, Stenzel E, Wetter A, Guberina N, Umutlu L, Schlosser T, Nassenstein K. Third generation dual-energy CT with 80/150 Sn kV for head and neck tumor imaging. Acta Radiol 2019; 60:586-592. [PMID: 30089396 DOI: 10.1177/0284185118788896] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Dual-energy CT (DECT) provides additional image datasets which enable improved tumor delineation or reduction of beam hardening artifacts in patients with head and neck squamous cell carcinoma (SCC). PURPOSE To assess radiation dose and image quality of third-generation DECT of the head and neck in comparison to single-energy CT (SECT). MATERIAL AND METHODS Thirty patients with SCC who underwent both SECT (reference tube voltage 120 kVp) and DECT (80/150 Sn kVp) of the head and neck region for staging were retrospectively selected. Attenuation measurements of the sternomastoid muscle, internal jugular vein, submandibular gland and tongue were compared. Image noise was assessed at five anatomic levels. Subjective image quality was evaluated by two radiologists in consensus. RESULTS CTDIvol was 55% lower with DECT (4.2 vs. 9.3 mGy; P = 0.002). Median image noise was equal or lower in DECT at all levels (nasopharynx: 3.9 vs. 5.8, P < 0.0001; floor of mouth: 3.6 vs. 4.5, P = 0.0002; arytenoids: 3.6 vs. 3.1, P = 0.096; lower thyroid: 4.4 vs. 5.7, P = 0.002; arch of aorta: 5.6 vs. 6.5, P = 0.001). Attenuation was significantly lower in DECT ( P < 0.05). Subjective image analysis revealed that DECT is equal or superior to SECT with regard to overall image quality (nasopharynx: 5 vs. 5, P = 1; floor of mouth: 5 vs. 5, P = 0.0041; arytenoids: 5 vs. 5, P = 0.6; lower thyroid: 5 vs. 3, P < 0.0001; arch of aorta: 5 vs. 4, P < 0.0001). CONCLUSION Head and neck imaging with third-generation DECT can reduce radiation dose by half compared to SECT, while maintaining excellent image quality.
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Affiliation(s)
- Saravanabavaan Suntharalingam
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Elena Stenzel
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Axel Wetter
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Nika Guberina
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Lale Umutlu
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Thomas Schlosser
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Kai Nassenstein
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
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8
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Clinical application of radiation dose reduction for head and neck CT. Eur J Radiol 2018; 107:209-215. [DOI: 10.1016/j.ejrad.2018.08.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/14/2018] [Accepted: 08/23/2018] [Indexed: 12/12/2022]
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Gharbi S, Labidi S, Mars M, Chelli M, Meftah S, Ladeb MF. Assessment of organ dose and image quality in head and chest CT examinations: a phantom study. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2018; 38:807-818. [PMID: 29869615 DOI: 10.1088/1361-6498/aac336] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The purpose of this study is to assess dose for radiosensitive organs and image quality in head and chest computed tomography (CT) examinations. Our focus was in the brain, eye lens and lung organs using two protocols; one protocol with fixed mAs and filtered back projection (FBP) and another with tube current modulation (TCM) and sinogram affirmed iterative reconstruction (SAFIRE). Measurements were performed on a 128-slice CT scanner by placing thermoluminescent dosimeters (TLDs) in an anthropomorphic adult phantom. Results were compared to a CT-Expo software. Objective image quality was assessed in terms of signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). SPSS software was used for data analyses. Results showed that, using TCM, doses were reduced by 22.84%-25.06% for brain, by 21.82%-23.48% for eye lens and by 54%-53.22% for lung with TLD and CT-Expo respectively. The increased SNR and CNR values achieved for scans performed with TCM combined with iterative reconstruction techniques were 38.68%-58.81% and 38.91%-43.60% respectively. We conclude that, using TCM, a significant mean organ dose reduction is achieved for brain, eye lens and lung organs. Then, combined with iterative reconstruction, image quality was well maintained in terms of SNR and CNR. Thus it is highly recommended in clinical practice optimization in head and chest CT examinations.
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Affiliation(s)
- S Gharbi
- Université Tunis EL Manar, Institut Supérieur des Technologies Médicales de Tunis, Laboratoire de recherche de Biophysique et de Technologies Médicales, 9, Avenue du Docteur Z. Essafi, Tunis 1006, Tunisia
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Chi BH, Chang IH, Lee DH, Park SB, Kim KD, Moon YT, Hur T. Low-Dose Unenhanced Computed Tomography with Iterative Reconstruction for Diagnosis of Ureter Stones. Yonsei Med J 2018; 59:389-396. [PMID: 29611401 PMCID: PMC5889991 DOI: 10.3349/ymj.2018.59.3.389] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 02/06/2018] [Accepted: 02/08/2018] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To study the clinical application of low-dose unenhanced computed tomography with iterative reconstruction technique (LDCT-IR) on renal colic in the emergency department. MATERIALS AND METHODS We conducted a prospective, single-blinded, randomized, and non-inferiority study. From March 2014 to August 2015, 112 patients with renal colic were included, and were randomized to either LDCT-IR (n=46) or standard-dose unenhanced CT (SDCT) (n=66) groups. The accuracy of urolithiasis diagnosis was the primary endpoint of this study. Radiation dose, size and location of the stone, hydronephrosis, other diseases except urolithiasis, and results of treatment were analyzed between the two groups. RESULTS The average effective dose radiation of SDCT was approximately four times higher than that of LDCT-IR (6.52 mSv vs. 1.63 mSv, p<0.001). There was no significant difference in the accuracy of ureteral stone diagnosis between the two groups (LDCT-IR group: 96.97% vs. SDCT group: 98.96%, p=0.392). No significant difference was observed regarding the size and location of a stone, hydronephrosis, and diagnosis of other diseases, except urolithiasis. False negative results were found in two LDCT-IR patients and in one SDCT patient. In these patients, stones were misread as vascular calcification, and were difficult to diagnose because evidence of hydronephrosis and ureteral dilatation was not found. CONCLUSION LDCT-IR, as a first-line imaging test, was non-inferior to SDCT with respect to diagnosis of ureter stones, and was clinically available for the evaluation of renal colic.
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Affiliation(s)
- Byung Hoon Chi
- Department of Urology, College of Medicine, Chung-Ang University, Seoul, Korea
| | - In Ho Chang
- Department of Urology, College of Medicine, Chung-Ang University, Seoul, Korea
| | - Dong Hoon Lee
- Department of Emergency Medicine, College of Medicine, Chung-Ang University, Seoul, Korea.
| | - Sung Bin Park
- Department of Radiology, College of Medicine, Chung-Ang University, Seoul, Korea
| | - Kyung Do Kim
- Department of Urology, College of Medicine, Chung-Ang University, Seoul, Korea
| | - Young Tae Moon
- Department of Urology, College of Medicine, Chung-Ang University, Seoul, Korea
| | - Taekyu Hur
- Chung-Ang University School of Medicine, Seoul, Korea
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Signal-to-noise ratio and dose to the lens of the eye for computed tomography examination of the brain using an automatic tube current modulation system. Emerg Radiol 2016; 24:233-239. [PMID: 27909929 DOI: 10.1007/s10140-016-1470-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 11/15/2016] [Indexed: 10/24/2022]
Abstract
PURPOSE The study aimed to evaluate the image quality in terms of signal-to-noise ratio (SNR) and dose to the lens of the eye and the other nearby organs from the CT brain scan using an automatic tube current modulation (ATCM) system with or without CT gantry tilt is needed. METHODS An anthropomorphic phantom was scanned with different settings including use of different ATCM, fixed tube current time product (mAs) settings and degree angles of gantry tilt. Gafchromic film XR-QA2 was used to measure absorbed dose of the organs. Relative doses and SNR for the various scan settings were compared with the reference setting of the fixed 330 mAs. RESULTS Average absorbed dose for the lens of the eyes varied from 8.7 to 21.7 mGy. The use of the ATCM system with the gantry tilt resulted in up to 60% decrease in the dose to the lens of the eye. SNR significantly decreased while tilting the gantry using the fixed mAs techniques, compared to that of the reference setting. However, there were no statistical significant differences for SNRs between the reference setting and all ATCM settings. CONCLUSIONS Compared to the reference setting of the fixed effective mAs, using the ATCM system and appropriate tilting, the gantry resulted in a substantial decrease in the dose to the lens of the eye while preserving signal-to-noise ratio. CT brain examination should be carefully controlled to optimize dose for lens of the eye and image quality of the examination.
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Park SB, Kim YS, Lee JB, Park HJ. Knowledge-based iterative model reconstruction (IMR) algorithm in ultralow-dose CT for evaluation of urolithiasis: evaluation of radiation dose reduction, image quality, and diagnostic performance. ACTA ACUST UNITED AC 2016. [PMID: 26197735 DOI: 10.1007/s00261-015-0504-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE To evaluate the efficacy of a knowledge-based iterative model reconstruction (IMR) algorithm for reducing image noise in ultralow-dose (ULD) CT for urolithiasis. MATERIALS AND METHODS A total of 103 patients diagnosed with urinary stones (n = 276) were enrolled. Regular dose (RD) scans (120 kV and 150 mAs, maximal tube current in dose modulation) were reconstructed using filtered back-projection (FBP, RD-FBP), and ULD scans (100 kV and 20 mAs, fixed tube current) were reconstructed with FBP (ULD-FBP), statistical iterative reconstruction (IR; ULD-iDose), and a knowledge-based IMR algorithm (ULD-IMR). Prospective interpretations of the two scans were performed with respect to radiation dose, objective image noise, and subjective assessment. The subjective assessment was also evaluated with regard to each patient's body mass index (BMI, < 25 or ≥ 25 kg/m(2)). Using RD CT (RD-FBP) as the reference standard, two reviewers assessed the diagnostic performance and inter-observer agreement for ULD-IMR. RESULT The average effective doses with RD CT and ULD CT were 8.31 and 0.68 mSv, respectively, and the average radiation dose reduction rate was 91.82% (p < 0.01). The lowest objective image noise was observed with ULD-IMR (p < 0.01). Subjective assessment in ULD-IMR was comparable to that of RD-FBP, although RD-FBP remained statistically superior. For BMI, there was a statistically significant difference in subjective image quality between the normal (4.7 ± 0.54) and overweight or obese groups (4.2 ± 0.5) (p < 0.05). The ULD-IMR showed a greater than 75% concordant rate in overall stones and 100% in ureter stones larger than 3 mm. However, for stones <3 mm, neither reviewer had a good detection rate (45.5% and 56.9% for the general and genitourinary radiologist, respectively). Inter-observer agreement was almost perfect (κ = 0.82). CONCLUSION Despite a significant radiation dose reduction, ULD-IMR images were comparable in image quality and noise to RD-FBP images. Furthermore, the diagnostic performance of the ULD non-enhanced CT protocol was comparable to that of the RD scan for diagnosing urinary stones larger than 3 mm.
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Affiliation(s)
- Sung Bin Park
- Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, 102, Heukseok-ro, Dongjak-gu, Seoul, 156-755, Korea.
| | - Yang Soo Kim
- Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, 102, Heukseok-ro, Dongjak-gu, Seoul, 156-755, Korea
| | - Jong Beum Lee
- Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, 102, Heukseok-ro, Dongjak-gu, Seoul, 156-755, Korea
| | - Hyun Jeong Park
- Department of Radiology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, 102, Heukseok-ro, Dongjak-gu, Seoul, 156-755, Korea
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Abstract
As endoscopic sinus surgery (ESS) has evolved since its introduction to the United States, so has technology for imaging the sinonasal cavities. Although imaging is most frequently performed for evaluating chronic sinusitis refractory to medical therapy, its uses have expanded beyond inflammatory sinus disease. Multidetector Computed Tomography is the current workhorse for both diagnosis and preoperative planning in prospective ESS patients, while MR imaging remains a complementary tool for evaluating suspected tumors or intracranial and orbital complications of rhinosinusitis. In this article, the authors review current trends and potential future directions in the use of these modalities for sinus imaging.
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Affiliation(s)
- Benjamin Y Huang
- Department of Radiology, University of North Carolina, CB# 7510, 101 Manning Drive, Chapel Hill, NC 27599, USA.
| | - Brent A Senior
- Department of Otolaryngology-Head and Neck Surgery, University of North Carolina, CB# 7070, 170 Manning Drive, Chapel Hill, NC 27599, USA
| | - Mauricio Castillo
- Department of Radiology, University of North Carolina, CB# 7510, 101 Manning Drive, Chapel Hill, NC 27599, USA
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Schaafs LA, Lenk J, Hamm B, Niehues SM. Reducing the dose of CT of the paranasal sinuses: potential of an iterative reconstruction algorithm. Dentomaxillofac Radiol 2016; 45:20160127. [PMID: 27351346 DOI: 10.1259/dmfr.20160127] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To evaluate the feasibility and image quality of low-dose CT of the paranasal sinuses using iterative reconstruction with adaptive-iterative dose reduction in three dimensions (AIDR 3D) in comparison with conventional image protocols of older scanner generations. METHODS Sinus CT scans of 136 patients were assessed retrospectively. Patients underwent CT either with low-dose settings (Protocol A: 80 kV, 30 mA s; Protocol B: 120 kV, 15 mA s or C: 80 kV, 90 mA s) reconstructed using AIDR 3D (Protocols A and B) or filtered back projection (FBP) (Protocol C) or with standard dose (Protocol D: 120 kV, 80 mA s) and FBP. Image quality was assessed in consensus by two blinded readers scoring the diagnostic image quality (from 1 = excellent to 5 = non-diagnostic) and conspicuity of important anatomic landmarks (from 0 = not visible to 2 = completely visible; maximum score of 16 points) as well as osseous structures (maximum score of 12 points). Dose-length product, effective dose (ED), CT dose index and scan length were retrieved for each scan and compared. RESULTS Mean ED could be lowered by 82% when using Protocol A. The best image quality was found using Protocol B (mean score = 2.1 ± 0.51). Conspicuity of relevant anatomic landmarks was best with Protocol A (mean score = 11.97 ± 1.88). Protocol B provided the highest conspicuity of osseous structures (mean score = 8.27 ± 1.58). Image noise was highest in images obtained using Protocol A. CONCLUSIONS AIDR 3D allows a significant dose reduction while maintaining a good diagnostic image quality and conspicuity of relevant anatomic structures.
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Affiliation(s)
- Lars-Arne Schaafs
- Department of Radiology, Campus Benjamin Franklin, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Julian Lenk
- Department of Radiology, Campus Benjamin Franklin, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Bernd Hamm
- Department of Radiology, Campus Benjamin Franklin, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Stefan Markus Niehues
- Department of Radiology, Campus Benjamin Franklin, Charité-Universitätsmedizin Berlin, Berlin, Germany
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How Much Is the Dose Varying between Follow-Up CT-Examinations Performed on the Same Scanner with the Same Imaging Protocol? PLoS One 2016; 11:e0152961. [PMID: 27050659 PMCID: PMC4822887 DOI: 10.1371/journal.pone.0152961] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Accepted: 03/22/2016] [Indexed: 12/12/2022] Open
Abstract
Purpose To investigate the dose variation between follow-up CT examinations, when a patient is examined several times on the same scanner with the identical scan protocol which comprised automated exposure control. Material and Methods This retrospective study was approved by the local ethics committee. The volume computed tomography dose index (CTDIvol) and the dose-length-product (DLP) were recorded for 60 cancer patients (29 male, 31 female, mean age 60.1 years), who received 3 follow-up CT examinations each composed of a non-enhanced scan of the liver (LI-CT) and a contrast-enhanced scan of chest (CH-CT) and abdomen (AB-CT). Each examination was performed on the same scanner (Siemens Definition FLASH) equipped with automated exposure control (CARE Dose 4D and CARE KV) using the identical scan protocol. Results The median percentage difference in DLP between follow-up examinations was 9.6% for CH-CT, 10.3% for LI-CT, and 10.1% for AB-CT; the median percentage difference in CTDIvol 8.3% for CH-CT, 7.4% for LI-CT and 7.7% for AB-CT (p<0.0001 for all values). The maximum difference in DLP between follow-up examinations was 67.5% for CH-CT, 50.8% for LI-CT and 74.3% for AB-CT; the maximum difference in CTDIvol 62.9% for CH-CT, 47.2% for LI-CT, and 49% for AB-CT. Conclusion A significant variance in the radiation dose occurs between follow-up CT examinations when the same CT scanner and the identical imaging protocol are used in combination with automated exposure control.
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Few-View Prereconstruction Guided Tube Current Modulation Strategy Based on the Signal-to-Noise Ratio of the Sinogram. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2015; 2015:906452. [PMID: 26089980 PMCID: PMC4450296 DOI: 10.1155/2015/906452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 12/27/2014] [Accepted: 12/28/2014] [Indexed: 11/23/2022]
Abstract
The radiation dose reduction without sacrificing the image quality as an important issue has raised the attention of CT manufacturers and different automatic exposure control (AEC) strategies have been adopted in their products. In this paper, we focus on the strategy of tube current modulation. It is deduced based on the signal-to-noise (SNR) of the sinogram. The main idea behind the proposed modulation strategy is to keep the SNR of the sinogram proximately invariable using the few-view reconstruction as a good reference because it directly affects the noise level of the reconstructions. The numerical experiment results demonstrate that, compared with constant tube current, the noise distribution is more uniform and the SNR and CNR of the reconstruction are better when the proposed strategy is applied. Furthermore it has the potential to distinguish the low-contrast target and to reduce the radiation dose.
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Baskan O, Erol C, Ozbek H, Paksoy Y. Effect of radiation dose reduction on image quality in adult head CT with noise-suppressing reconstruction system with a 256 slice MDCT. J Appl Clin Med Phys 2015; 16:5360. [PMID: 26103494 PMCID: PMC5690139 DOI: 10.1120/jacmp.v16i3.5360] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 01/23/2015] [Accepted: 01/21/2015] [Indexed: 11/23/2022] Open
Abstract
The purpose of our study was to investigate the effect of iterative reconstruction (IR) as a dose reduction system on the image quality (IQ) of the adult head computed tomography (CT) at various low‐dose levels, and to identify ways of setting the amount of dose reduction. We performed two noncontrast low‐dose (LD) adult head CT protocols modified by lowering the tube current with IR which were decided in the light of a group of phantom studies. Two groups of patients, each 100 underwent noncontrast head CT with LD‐I and LD‐II, respectively. These groups were compared with 100 consecutive standard dose (STD) adult head CT protocol in terms of quantitative and qualitative IQ. The signal‐to‐noise ratio (SNR) of the white matter (WM) and gray matter (GM) and contrast‐to‐noise ratio (CNR) values in the LD groups were higher than the STD group. The differences were statistically significant. When the STD and the LD groups were compared qualitatively, no significant differences were found in overall quality. By selecting the appropriate level of IR 34%, radiation dose reduction in adult head CT can be achieved without compromising IQ. PACS number: 87.57.‐s
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CT for evaluation of urolithiasis: image quality of ultralow-dose (Sub mSv) CT with knowledge-based iterative reconstruction and diagnostic performance of low-dose CT with statistical iterative reconstruction. ACTA ACUST UNITED AC 2015; 40:2432-40. [PMID: 25833747 DOI: 10.1007/s00261-015-0411-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Parmar HA, Ibrahim M, Mukherji SK. Optimizing Craniofacial CT Technique. Neuroimaging Clin N Am 2014; 24:395-405, vii. [DOI: 10.1016/j.nic.2014.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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