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Li Y, Liu X, Zhuang XH, Wang MJ, Song XF. Assessment of low-dose paranasal sinus CT imaging using a new deep learning image reconstruction technique in children compared to adaptive statistical iterative reconstruction V (ASiR-V). BMC Med Imaging 2022; 22:106. [PMID: 35658908 PMCID: PMC9164403 DOI: 10.1186/s12880-022-00834-1] [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: 12/21/2021] [Accepted: 05/27/2022] [Indexed: 11/23/2022] Open
Abstract
Purpose To compare the effects of deep learning image reconstruction (DLIR) and adaptive statistical iterative reconstruction V (ASiR-V) on image quality in low-dose computed tomography (CT) of paranasal sinuses in children. Methods Low-dose CT scans of the paranasal sinuses in 25 pediatric patients were retrospectively evaluated. The raw data were reconstructed with three levels of DLIR (high, H; medium, M; and low, L), filtered back projection (FBP), and ASiR-V (30% and 50%). Image noise was measured in both soft tissue and bone windows, and the signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) of the images were calculated. Subjective image quality at the ethmoid sinus and nasal cavity levels of the six groups of reconstructed images was assessed by two doctors using a five-point Likert scale in a double-blind manner. Results The patients’ mean dose-length product and effective dose were 36.65 ± 2.44 mGy·cm and 0.17 ± 0.03 mSv, respectively. (1) Objective evaluation: 1. Soft tissue window: The difference among groups in each parameter was significant (P < 0.05). Pairwise comparisons showed that the H group’ s parameters were significantly better (P < 0.05) than those of the 50% post-ASiR-V group. 2. Bone window: No significant between-group differences were found in the noise of the petrous portion of the temporal bone or its SNR or in the noise of the pterygoid processes of the sphenoids or their SNRs (P > 0.05). Significant differences were observed in the background noise and CNR (P < 0.05). As the DLIR intensity increased, image noise decreased and the CNR improved. The H group exhibited the best image quality. (2) Subjective evaluation: Scores for images of the ethmoid sinuses were not significantly different among groups (P > 0.05). Scores for images of the nasal cavity were significantly different among groups (P < 0.05) and were ranked in descending order as follows: H, M, L, 50% post-ASiR-V, 30% post-ASiR-V, and FBP. Conclusion DLIR was superior to FBP and post-ASiR-V in low-dose CT scans of pediatric paranasal sinuses. At high intensity (H), DLIR provided the best reconstruction effects.
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Patient dose in CT angiography examinations: An institutional survey. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Effect of Body Mass Index in Coronary CT Angiography Performed on a 256-Slice Multi-Detector CT Scanner. Diagnostics (Basel) 2022; 12:diagnostics12020319. [PMID: 35204410 PMCID: PMC8871507 DOI: 10.3390/diagnostics12020319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/18/2022] [Accepted: 01/24/2022] [Indexed: 12/21/2022] Open
Abstract
We aimed to investigate the effect of a patient’s body mass index (BMI) on radiation dose and image quality in prospectively ECG-triggered coronary CT angiography (CCTA) performed on a 256-slice multi-detector CT scanner. In total, 87 consecutive patients receiving CCTA examinations acquired with tube current modulation (TCM) and iterative reconstruction (IR) were enrolled in this study. The dose report recorded from the CT scanner console was used to derive the effective dose for patients. Subjective image quality scoring and objective noise measurements were conducted to quantify the impact of BMI on the image quality of CCTA. Because of the TCM technique, we expected tube current and radiation dose to increase as BMI increased. However, using TCM did not always guarantee sufficient radiation exposure to achieve consistent image quality for overweight or obese patients since the maximum X-ray tube output in milliamperes and kilovoltage peak was reached. The impact of photon starvation noise on image quality was not significant until BMI ≥ 27 kg/m2; this result could be due to IR’s noise reduction capability. Our results also suggest that using TCM with a noise index of 25 HU can reduce radiation dose without compromising image quality compared to images obtained based on the manufacturer’s default settings.
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Yue W, Yang W, peng H, Zhong Feng N, Hong Jie H. Comparative study of the image quality of twin beam dual energy and single energy carotid CT angiography. Eur J Radiol 2022; 148:110160. [DOI: 10.1016/j.ejrad.2022.110160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/18/2021] [Accepted: 01/12/2022] [Indexed: 12/14/2022]
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Multiphase vascular lower limb computed tomography: Assessment of patients doses and radiogenic risk. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109675] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Hou KY, Tsujioka K, Yang CC. Optimization of HU threshold for coronary artery calcium scans reconstructed at 0.5-mm slice thickness using iterative reconstruction. J Appl Clin Med Phys 2020; 21:111-120. [PMID: 31889419 PMCID: PMC7021007 DOI: 10.1002/acm2.12806] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/30/2019] [Accepted: 12/13/2019] [Indexed: 12/22/2022] Open
Abstract
PURPOSE This work investigated the simultaneous influence of tube voltage, tube current, body size, and HU threshold on calcium scoring reconstructed at 0.5-mm slice thickness using iterative reconstruction (IR) through multivariate analysis. Regression results were used to optimize the HU threshold to calibrate the resulting Agatston scores to be consistent with those obtained from the conventional protocol. METHODS A thorax phantom set simulating three different body sizes was used in this study. A total of 14 coronary artery calcium (CAC) protocols were studied, including 1 conventional protocol reconstructed at 3-mm slice thickness, 1 FBP protocol, and 12 statistical IR protocols (3 kVp values*4 SD values) reconstructed at 0.5-mm slice thickness. Three HU thresholds were applied for calcium identification, including 130, 150, and 170 HU. A multiple linear regression method was used to analyze the impact of kVp, SD, body size, and HU threshold on the Agatston scores of three calcification densities for IR-reconstructed CAC scans acquired with 0.5-mm slice thickness. RESULTS Each regression relationship has R2 larger than 0.80, indicating a good fit to the data. Based on the regression models, the HU thresholds as a function of SD estimated to ensure the quantification accuracy of calcium scores for 120-, 100-, and 80-kVp CAC scans reconstructed at 0.5-mm slice thickness using IR for three different body sizes were proposed. Our results indicate that the HU threshold should be adjusted according to the imaging condition, whereas a 130-HU threshold is appropriate for 120-kVp CAC scans acquired with SD = 55 for body size of 24.5 cm. CONCLUSION The optimized HU thresholds were proposed for CAC scans reconstructed at 0.5-mm slice thickness using IR. Our study results may provide a potential strategy to improve the reliability of calcium scoring by reducing partial volume effect while keeping radiation dose as low as reasonably achievable.
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Affiliation(s)
- Kuei-Yuan Hou
- Department of Radiology, Cathay General Hospital, Taipei, Taiwan
| | - Katsumi Tsujioka
- Faculty of Radiological Technology, Fujita Health University, Aichi, Japan
| | - Ching-Ching Yang
- Department of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan
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Qurashi AA, Rainford LA, Alshamrani KM, Foley SJ. THE IMPACT OF OBESITY ON ABDOMINAL CT RADIATION DOSE AND IMAGE QUALITY. RADIATION PROTECTION DOSIMETRY 2019; 185:17-26. [PMID: 30508172 DOI: 10.1093/rpd/ncy212] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 11/02/2018] [Accepted: 11/07/2018] [Indexed: 06/09/2023]
Abstract
The aim of this study was to evaluate how iterative reconstruction can compensate for the noise increase in low radiation dose abdominal computed tomography (CT) technique for large size patients and the general impact of obesity on abdominal organ doses and image quality in CT. An anthropomorphic phantom layered with either none or a single layer of 3-cm- thick circumferential animal fat packs to simulate obese patients was imaged using a 128MDCT scanner. Abdominal protocols (n = 12) were applied using automatic tube current modulation (ATCM) with various quality reference mAs (150, 200, 250 and 300). kVs of 100, 120 and 140 were used for each mAs selection. Metal oxide semiconductor field effect transistor dosimeters (MOSFET) measured internal organ dose. All images produced were reconstructed with filtered back projection (FBP) and sinogram affirmed iterative reconstruction (SAFIRE) (3, 4 and 5) and objective noise was measured within three regions of interest at the level of L4-L5. Organ doses varied from 0.12 to 41.9 mGy, the spleen received the highest doses for both phantom sizes. Compared to the phantom simulating average size, the obese phantom was associated with up to twofold increase in delivered mAs, dose length product (DLP) and computed tomography dose index (CTDIvol) for the matched mAs selection (p < 0.05). However, organ dose increased by 50% only. The use of 100 kV resulted in a 40% lower dose (p < 0.05) compared to 120 kV and the associated noise increase was improved by SAFIRE (5) use, which resulted in 60% noise reduction compared to FBP (p < 0.05). When combined with iterative reconstruction, low kV is feasible for obese patients to optimise radiation dose and maintain objective image quality.
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Affiliation(s)
- Abdulaziz A Qurashi
- Department of Diagnostic Radiologic Technology, College of Applied Medical Sciences, Taibah University, Madinah, Saudi Arabia
| | - Louise A Rainford
- Radiography & Diagnostic Imaging, School of Medicine, University College Dublin, Dublin, Ireland
| | - Khalid M Alshamrani
- Radiological Sciences, College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
| | - Shane J Foley
- Radiography & Diagnostic Imaging, School of Medicine, University College Dublin, Dublin, Ireland
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Zhang L, Chen YF, Che YX, Xu YF, Zheng J, Yu SJ. The impact of adaptive iterative dose reduction 3D on the improvement of shoulder image quality in head and neck CTA. Curr Med Res Opin 2019; 35:887-891. [PMID: 30366505 DOI: 10.1080/03007995.2018.1541446] [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] [Indexed: 10/28/2022]
Abstract
OBJECTIVE The aim of this study was to determine the impact of adaptive iterative dose reduction 3 D (AIDR3D) on the improvement of shoulder image quality in low-radiographic dose head and neck CT angiography (CTA). MATERIALS AND METHODS Ninety patients who underwent CTA examination were randomly divided into two groups, namely group A (n = 45) and B (n = 45). Patients in group A were scanned under 120 kV and 300 mA, with images reconstructed by filtered back projection (FBP), and patients in group B were scanned under 80 kV and auto mA with images reconstructed by AIDR3D. Image quality was accessed by two experienced radiologists. The noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of common carotid artery (CCA) at C7 level, and radiation dosage were compared between the two groups. RESULTS The score of CCA in group B was significantly higher than group A (p < 0.05), and there were no significant differences in the scores of carotid sinus and internal carotid artery between the two groups (p > 0.05). The score of intracranial artery in group B was lower than that of group A, however, the image quality in group B can meet the requirement of clinical diagnosis. The noise value of CCA at C7 level in group B was significantly lower than that of group A (p < 0.05). SNR and CNR values of CCA at C7 level in group B were significantly higher than those of group A (p < 0.05). Effective radiation dose in group B was significantly decreased compared with group A (p < 0.05). CONCLUSION AIDR3D remarkably improved image quality in low-radiographic dose head and neck CTA over FBP, which made the low-dose CTA images meet the requirement of clinical diagnosis.
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Affiliation(s)
- Li Zhang
- a Department of CT Diagnosis , Cangzhou Central Hospital , Cangzhou , Hebei 061001 , PR China
| | - Yue-Feng Chen
- a Department of CT Diagnosis , Cangzhou Central Hospital , Cangzhou , Hebei 061001 , PR China
| | - Yan-Xu Che
- a Department of CT Diagnosis , Cangzhou Central Hospital , Cangzhou , Hebei 061001 , PR China
| | - Yan-Feng Xu
- a Department of CT Diagnosis , Cangzhou Central Hospital , Cangzhou , Hebei 061001 , PR China
| | - Jing Zheng
- a Department of CT Diagnosis , Cangzhou Central Hospital , Cangzhou , Hebei 061001 , PR China
| | - Shu-Jing Yu
- a Department of CT Diagnosis , Cangzhou Central Hospital , Cangzhou , Hebei 061001 , PR China
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Peña-Solórzano CA, Albrecht DW, Paganin DM, Harris PC, Hall CJ, Bassed RB, Dimmock MR. Development of a simple numerical model for trabecular bone structures. Med Phys 2019; 46:1766-1776. [PMID: 30740701 DOI: 10.1002/mp.13435] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/18/2019] [Accepted: 02/01/2019] [Indexed: 12/26/2022] Open
Abstract
PURPOSE Advances in additive manufacturing processes are enabling the fabrication of surrogate bone structures for applications including use in high-resolution anthropomorphic phantoms. In this research, a simple numerical model is proposed that enables the generation of microarchitecture with similar statistical distribution to trabecular bone. METHODS A human humerus, radius, ulna, and several vertebrae were scanned on the Imaging and Medical beamline at the Australian Synchrotron and the proposed numerical model was developed through the definition of two complex functions that encode the trabecular thickness and position-dependant spacing to generate volumetric surrogate trabecular structures. The structures reproduced those observed at 19 separate axial locations through the experimental bone volumes. The applicability of the model when incorporating a two-material approximation to absorption- and phase-contrast CT was also investigated through simulation. RESULTS The synthetic structures, when compared with the real trabecular microarchitecture, yielded an average mean thickness error of 2 μm, and a mean difference in standard deviation of 33 μm for the humerus, 24 μm for the ulna and radius, and 15 μm for the vertebrae. Simulated absorption- and propagation-based phase contrast CT projection data were generated and reconstructed using the derived mathematical simplifications from the two-material approximation, and the phase-contrast effects were successfully demonstrated. CONCLUSIONS The presented model reproduced trabecular distributions that could be used to generate phantoms for quality assurance and validation processes. The implication of utilizing a two-material approximation results in simplification of the additive manufacturing process and the generation of synthetic data that could be used for training of machine learning applications.
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Affiliation(s)
- Carlos A Peña-Solórzano
- Department of Medical Imaging and Radiation Sciences, Monash University, Melbourne, Vic., 3800, Australia
| | - David W Albrecht
- Faculty of Information Technology, Monash University, Melbourne, Vic., 3800, Australia
| | - David M Paganin
- School of Physics and Astronomy, Monash University, Melbourne, Vic., 3800, Australia
| | - Peter C Harris
- Department of Orthopaedic Surgery, Western Health, Footscray Hospital, Melbourne, Vic., 3011, Australia.,The Royal Children's Hospital Melbourne, Melbourne, Vic., 3052, Australia
| | - Chris J Hall
- Imaging and Medical Beam Line, ANSTO Australian Synchrotron, Melbourne, Vic., 3168, Australia
| | - Richard B Bassed
- Victorian Institute of Forensic Medicine, Melbourne, Vic., 3006, Australia.,Department of Forensic Medicine, Monash University, Melbourne, Vic., 3800, Australia
| | - Matthew R Dimmock
- Department of Medical Imaging and Radiation Sciences, Monash University, Melbourne, Vic., 3800, Australia
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Ittrich H, Bockhorn M, Klose H, Simon M. The Diagnosis and Treatment of Hemoptysis. DEUTSCHES ARZTEBLATT INTERNATIONAL 2018. [PMID: 28625277 DOI: 10.3238/arztebl.2017.0371] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Hemoptysis, i.e., the expectoration of blood from the lower airways, has an annual incidence of approximately 0.1% in ambulatory patients and 0.2% in inpatients. It is a potentially life-threatening medical emergency and carries a high mortality. METHODS This review article is based on pertinent publications retrieved by a selective search in PubMed. RESULTS Hemoptysis can be a sign of many different diseases. Its cause remains unknown in about half of all cases. Its more common recognized causes include infectious and inflammatory airway diseases (25.8%) and cancer (17.4%). Mild hemoptysis is self-limited in 90% of cases; massive hemoptysis carries a worse prognosis. In patients whose life is threatened by massive hemoptysis, adequate oxygenation must be achieved through the administration of oxygen, positioning of the patient with the bleeding side down (if known), and temporary intubation if necessary. A thorough diagnostic evaluation is needed to identify the underlying pathology, site of bleeding, and vascular anatomy, so that the appropriate treatment can be planned. The evaluation should include conventional chest x-rays in two planes, contrastenhanced multislice computerized tomography, and bronchoscopy. Hemostasis can be achieved at bronchoscopically accessible bleeding sites with interventionalbronchoscopic local treatment. Bronchial artery embolization is the first line of treatment for hemorrhage from the pulmonary periphery; it is performed to treat massive or recurrent hemoptysis or as a presurgical measure and provides successful hemostasis in 75-98% of cases. Surgery is indicated if bronchial artery embolization alone is not successful, or for special indications (traumatic or iatrogenic pulmonary/vascular injury, refractory asper gilloma). CONCLUSION The successful treatment of hemoptysis requires thorough diagnostic evaluation and close interdisciplinary collaboration among pulmonologists, radiologists, and thoracic surgeons.
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Affiliation(s)
- Harald Ittrich
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, Center for Radiology and Endoscopy, University Medical Center Hamburg-Eppendorf, Hamburg; Department of General, Visceral and Thoracic Surgery, Center for Surgical Sciences, University Medical Center Hamburg-Eppendorf, Hamburg; Department of Pulmonology, II. Medical Clinic, University Medical Center Hamburg-Eppendorf, Hamburg
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Low-tube-voltage combined with adaptive statistical iterative reconstruction-V technique in CT venography of lower limb deep vein thrombosis. Sci Rep 2018; 8:11174. [PMID: 30042394 PMCID: PMC6057885 DOI: 10.1038/s41598-018-29519-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 07/11/2018] [Indexed: 12/11/2022] Open
Abstract
This study contains 2 arms: (1) the ASIR-V technique combined with low-tube-voltage in lower limb deep vein thrombosis (DVT) diagnosis was investigated; and (2) CT venography and ultrasound results in DVT diagnosis were compared. For arm 1, 90 patients suspected of DVT were randomly divided into 3 groups (30/group): groups A and B were scanned under 100-kV with pre-set ASIR-V weights of 30% and 50% respectively; group C were scanned under 70-kV with a 50% weight. For arm 2, 75 patients were divided into 3 groups (25/group), each group was CT scanned as in arm 1 and then all subjects were examined by ultrasound. Groups A, B and C had 16, 14 and 17 patients diagnosed with DVTs, respectively. There was no significant difference in subjective ratings of image quality among all groups. The 70-kV protocol remarkably increased venous attenuation value while all groups had similar DVT attenuation value. Higher noise was observed in group C, the CNR however, was actually augmented due to elevated venous attenuations. More importantly, group C had significantly lower CTDIvol and DLP values. In conclusion, the 70-kV protocol is superior to the 100 kV protocols, which was supported by findings from the second arm study.
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Task-based quantification of image quality using a model observer in abdominal CT: a multicentre study. Eur Radiol 2018; 28:5203-5210. [PMID: 29858638 PMCID: PMC6223860 DOI: 10.1007/s00330-018-5518-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 04/19/2018] [Accepted: 04/26/2018] [Indexed: 11/23/2022]
Abstract
Objective We investigated the variability in diagnostic information inherent in computed tomography (CT) images acquired at 68 different CT units, with the selected acquisition protocols aiming to answer the same clinical question. Methods An anthropomorphic abdominal phantom with two optional rings was scanned on 68 CT systems from 62 centres using the local clinical acquisition parameters of the portal venous phase for the detection of focal liver lesions. Low-contrast detectability (LCD) was assessed objectively with channelised Hotelling observer (CHO) using the receiver operating characteristic (ROC) paradigm. For each lesion size, the area under the ROC curve (AUC) was calculated and considered as a figure of merit. The volume computed tomography dose index (CTDIvol) was used to indicate radiation dose exposure. Results The median CTDIvol used was 5.8 mGy, 10.5 mGy and 16.3 mGy for the small, medium and large phantoms, respectively. The median AUC obtained from clinical CT protocols was 0.96, 0.90 and 0.83 for the small, medium and large phantoms, respectively. Conclusions Our study used a model observer to highlight the difference in image quality levels when dealing with the same clinical question. This difference was important and increased with growing phantom size, which generated large variations in patient exposure. In the end, a standardisation initiative may be launched to ensure comparable diagnostic information for well-defined clinical questions. The image quality requirements, related to the clinical question to be answered, should be the starting point of patient dose optimisation. Key Points • Model observers enable to assess image quality objectively based on clinical tasks. • Objective image quality assessment should always include several patient sizes. • Clinical diagnostic image quality should be the starting point for patient dose optimisation. • Dose optimisation by applying DRLs only is insufficient for ensuring clinical requirements.
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Kim YN, Song JS, Moon WS, Hwang HP, Kim YK. Intra-individual comparison of hepatocellular carcinoma imaging features on contrast-enhanced computed tomography, gadopentetate dimeglumine-enhanced MRI, and gadoxetic acid-enhanced MRI. Acta Radiol 2018; 59:639-648. [PMID: 28825310 DOI: 10.1177/0284185117728534] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Background Gadoxetic acid is being widely used for detection and characterization of hepatic nodules. However, there are no data regarding intra-individual comparison of imaging features of hepatocellular carcinoma (HCC) on dynamic computed tomography (CT), gadopentetate dimeglumine-enhanced magnetic resonance imaging (Gd-DTPA-MRI), and gadoxetic acid-enhanced MRI (Gd-EOB-MRI). Purpose To evaluate typical imaging features of HCC and capsule appearance with dynamic CT, Gd-DTPA-MRI, and Gd-EOB-MRI. Material and Methods We retrospectively reviewed 56 HCCs in 49 patients. Lesion attenuation/signal intensity was graded using a five-point scale based on dynamic phase and hepatobiliary phase (HBP) imaging. Subjective washout and capsule appearance were evaluated on portal venous phase (PVP) or delayed/transitional phase (DP/TP) imaging. The tumor-to-liver contrast ratio (TLCR) was calculated. Results Gd-DTPA-MRI and Gd-EOB-MRI was graded higher than CT on arterial phase ( P < 0.001). Gd-EOB-MRI was graded lower than Gd-DTPA-MRI on PVP and DP/TP ( P < 0.05). The detection rate of subjective washout and capsule appearance did not differ among the three imaging studies on either PVP or DP/TP. TLCR of Gd-EOB-MRI was lower than CT on PVP ( P = 0.004) and was lower than Gd-DTPA-MRI on DP/TP ( P = 0.001). Conclusion Arterial phase hyperenhancement and washout appearance of HCC were well demonstrated in Gd-EOB-MRI. The detection of capsule appearance using Gd-EOB-MRI was not inferior to Gd-DTPA-MRI or CT.
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Affiliation(s)
- Yo Na Kim
- Department of Pathology, Chonbuk National University Medical School, Chonbuk, Republic of Korea
| | - Ji Soo Song
- Department of Radiology, Chonbuk National University Medical School and Hospital, Chonbuk, Republic of Korea
- Research Institute of Clinical Medicine of Chonbuk National University, Chonbuk, Republic of Korea
- Biomedical Research Institute of Chonbuk National University Hospital, Chonbuk, Republic of Korea
| | - Woo Sung Moon
- Department of Pathology, Chonbuk National University Medical School, Chonbuk, Republic of Korea
| | - Hong Pil Hwang
- Department of Surgery, Chonbuk National University Medical School, Chonbuk, Republic of Korea
| | - Young Kon Kim
- Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Sungkyunkwan, Republic of Korea
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Sun Y, Hua Y, Wang M, Mao D, Jin X, Li C, Shi K, Xu J. Evaluation of a High Concentrated Contrast Media Injection Protocol in Combination with Low Tube Current for Dose Reduction in Coronary Computed Tomography Angiography: A Randomized, Two-center Prospective Study. Acad Radiol 2017; 24:1482-1490. [PMID: 28800951 DOI: 10.1016/j.acra.2017.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 07/03/2017] [Accepted: 07/05/2017] [Indexed: 11/25/2022]
Abstract
RATIONALE AND OBJECTIVES The study aimed to prospectively evaluate the radiation dose reduction potential and image quality (IQ) of a high-concentration contrast media (HCCM) injection protocol in combination with a low tube current (mAs) in coronary computed tomography angiography. MATERIALS AND METHODS Eighty-one consecutive patients (mean age: 62 years; 34 females; body mass index: 18-31) were included and randomized-assigned into two groups. All computed tomography (CT) examinations were performed in two groups with the same tube voltage (100 kV), flow rate of contrast medium (5.0 mL/s), and iodine dose (22.8 g). An automatic mAs and low concentration contrast medium (300 mgI/mL) were used in group A, whereas effective mAs was reduced by a factor 0.6 along with HCCM (400 mgI/mL) in group B. Radiation dose was assessed (CT dose index [CTDIvol] and dose length product), and vessel-based objective IQ for various regions of interest (enhancement, noise, signal-to-noise ratio, and contrast-to-noise ratio), subjective IQ, noise, and motion artifacts were analyzed overall and vessel-based with a 5-point Likert scale. RESULTS The CT attenuation of coronary arteries and image noise in group B were significantly higher than those in group A (ranges: 507.5-548.1 Hounsfield units vs 407.5-444.5 Hounsfield units; and 20.3 ± 8.6 vs 17.7 ± 8.0) (P ≤ 0.0166). There was no significant difference between the two groups in signal-to-noise ratio, contrast-to-noise ratio, and subjective IQ of coronary arteries (29.4-31.7, 30.0-37.0, and medium score of 5 in group A vs 29.4-32.4, 27.7-36.3, and medium score of 5 in group B, respectively, P ≥ 0.1859). Both mean CTDIvol and dose length product in group B were 58% of those of group A. CONCLUSIONS HCCM combined with low tube current allows dose reduction in coronary computed tomography angiography and does not compromise IQ.
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Thompson JD, Wareing A, Szczepura KR, Vinjamuri S, Hogg P. A JAFROC study of nodule detection performance in CT images of a thorax acquired during PET/CT. Radiography (Lond) 2017; 23:191-196. [PMID: 28687285 DOI: 10.1016/j.radi.2017.03.001] [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: 12/13/2016] [Revised: 03/01/2017] [Accepted: 03/03/2017] [Indexed: 11/27/2022]
Abstract
PURPOSE Two types of CT images (modalities) are acquired in PET/CT: for attenuation correction (AC) and diagnosis. The purpose of the study was to compare nodule detection and localization performance between these two modalities. METHODS CT images, using both modalities, of an anthropomorphic chest phantom containing zero or more simulated spherical nodules of 5, 8, 10 and 12 mm diameters and contrasts -800, -630 and 100 HU were acquired. An observer performance study using nine observers interpreting 45 normal (zero nodules) images and 47 abnormal images (1-3 nodules; average 1.26) was conducted using the free-response receiver operating characteristic (FROC) paradigm. Data were analysed using an R software package implemented jackknife alternative FROC (JAFROC) analysis. Both empirical areas under the equally weighted AFROC curve (wAFROC) and under the highest rating inferred ROC (HR-ROC) curve were used as figures of merit (FOM). To control the probability of Type I error test alpha was set at 0.05. RESULTS Nodule detection as measured by either FOM was significantly better on the diagnostic quality images (2nd modality), irrespective of the method of analysis, [reader averaged inter-modality wAFROC FOM difference = -0.07 (-0.11,-0.04); reader averaged inter-modality HR-ROC FOM difference = -0.05 (-0.09, -0.01)]. CONCLUSION Nodule detection was statistically worse on images acquired for AC; suggesting that images acquired for AC should not be used to evaluate pulmonary pathology.
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Affiliation(s)
- J D Thompson
- Directorate of Radiography, University of Salford, Greater Manchester, M6 6PU, UK; Radiology, Furness General Hospital, University Hospitals of Morecambe Bay NHS Foundation Trust, Dalton Lane, Barrow-in-Furness, Cumbria, LA14 4LF, UK.
| | - A Wareing
- School of Health Sciences, Faculty of Health and Social Care, Robert Gordon University, Garthdee Road, Aberdeen, AB10 7QG, UK
| | - K R Szczepura
- Radiology, Furness General Hospital, University Hospitals of Morecambe Bay NHS Foundation Trust, Dalton Lane, Barrow-in-Furness, Cumbria, LA14 4LF, UK
| | - S Vinjamuri
- Department of Nuclear Medicine, Royal Liverpool and Broadgreen University Hospitals NHS Trust, Prescot Street, Liverpool, L7 8XP, UK
| | - P Hogg
- Radiology, Furness General Hospital, University Hospitals of Morecambe Bay NHS Foundation Trust, Dalton Lane, Barrow-in-Furness, Cumbria, LA14 4LF, UK; Karolinska Institute, Stockholm, SE-171 77, Sweden
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Aissa J, Boos J, Rubbert C, Caspers J, Schleich C, Thomas C, Kröpil P, Antoch G, Miese F. Optimizing radiation exposure in screening of body packing: image quality and diagnostic acceptability of an 80 kVp protocol with automated tube current modulation. Forensic Sci Med Pathol 2017; 13:145-150. [DOI: 10.1007/s12024-017-9848-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2017] [Indexed: 12/20/2022]
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Computed Tomographic Angiography of the Abdomen and Pelvis in Azotemic Patients Utilizing 80-kV(p) Technique and Reduced Dose Iodinated Contrast. J Comput Assist Tomogr 2017; 41:141-147. [DOI: 10.1097/rct.0000000000000478] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Shimonobo T, Funama Y, Utsunomiya D, Nakaura T, Oda S, Kiguchi M, Masuda T, Sakabe D, Yamashita Y, Awai K. Low-tube-voltage selection for non-contrast-enhanced CT: Comparison of the radiation dose in pediatric and adult phantoms. Phys Med 2016; 32:197-201. [DOI: 10.1016/j.ejmp.2015.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Revised: 11/30/2015] [Accepted: 12/11/2015] [Indexed: 11/30/2022] Open
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Spearman JV, Schoepf UJ, Rottenkolber M, Driesser I, Canstein C, Thierfelder KM, Krazinski AW, De Cecco CN, Meinel FG. Effect of Automated Attenuation-based Tube Voltage Selection on Radiation Dose at CT: An Observational Study on a Global Scale. Radiology 2015; 279:167-74. [PMID: 26473641 DOI: 10.1148/radiol.2015141507] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To evaluate the effect of automated tube voltage selection (ATVS) on radiation dose at computed tomography (CT) worldwide encompassing all body regions and types of CT examinations. MATERIALS AND METHODS No patient information was accessed; therefore, institutional review board approval was not sought. Data from 86 centers across the world were analyzed. All CT interactions were automatically collected and transmitted to the CT vendor during two 6-week periods immediately before and 2 weeks after implementation of ATVS. A total of 164 323 unique CT studies were analyzed. Studies were categorized by body region and type of examination. Tube voltage and volume CT dose index (CTDIvol) were compared between examinations performed with ATVS and those performed before ATVS implementation. Descriptive statistical methods and multilevel linear regression models were used for analysis. RESULTS Across all types of CT examinations and body regions, CTDIvol was 14.7% lower in examinations performed with ATVS (n = 30 313) than in those performed before ATVS implementation (n = 79 275). Relative reductions in mean CTDIvol were most notable for temporal bone CT (-56.1%), peripheral runoff CT angiography (-48.6%), CT of the paranasal sinus (-39.6%), cerebral or carotid CT angiography (-36.4%), coronary CT angiography (-25.1%), and head CT (-23.9%). An increase in mean CTDIvol was observed for renal stone protocols (26.2%) and thoracic or lumbar spine examinations (6.6%). In the multilevel model with fixed effects ATVS and examination type, and the interaction of these variables and the random effect country, a significant influence on CTDIvol for all fixed efects was revealed (ATVS, P = .0031; examination type, P < .0001; interaction term, P < .0001). CONCLUSION ATVS significantly reduces radiation dose across most, but not all, body regions and types of CT examinations.
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Affiliation(s)
- James V Spearman
- From the Division of Cardiovascular Imaging, Department of Radiology and Radiological Science (J.V.S., U.J.S., A.W.K., C.N.D.C., F.G.M.) and Division of Cardiology, Department of Medicine (U.J.S.), Medical University of South Carolina, 25 Courtenay Dr, MSC 226, Charleston, SC 29425; Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians-Universität, Munich, Germany (M.R.); Healthcare Division, Computed Tomography, Siemens, Forchheim, Germany (I.D.); Siemens Medical Solutions USA, Malvern, Pa (C.C.); Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (K.M.T., F.G.M.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome "Sapienza"-Polo Pontino, Latina, Italy (C.N.D.C.)
| | - U Joseph Schoepf
- From the Division of Cardiovascular Imaging, Department of Radiology and Radiological Science (J.V.S., U.J.S., A.W.K., C.N.D.C., F.G.M.) and Division of Cardiology, Department of Medicine (U.J.S.), Medical University of South Carolina, 25 Courtenay Dr, MSC 226, Charleston, SC 29425; Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians-Universität, Munich, Germany (M.R.); Healthcare Division, Computed Tomography, Siemens, Forchheim, Germany (I.D.); Siemens Medical Solutions USA, Malvern, Pa (C.C.); Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (K.M.T., F.G.M.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome "Sapienza"-Polo Pontino, Latina, Italy (C.N.D.C.)
| | - Marietta Rottenkolber
- From the Division of Cardiovascular Imaging, Department of Radiology and Radiological Science (J.V.S., U.J.S., A.W.K., C.N.D.C., F.G.M.) and Division of Cardiology, Department of Medicine (U.J.S.), Medical University of South Carolina, 25 Courtenay Dr, MSC 226, Charleston, SC 29425; Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians-Universität, Munich, Germany (M.R.); Healthcare Division, Computed Tomography, Siemens, Forchheim, Germany (I.D.); Siemens Medical Solutions USA, Malvern, Pa (C.C.); Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (K.M.T., F.G.M.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome "Sapienza"-Polo Pontino, Latina, Italy (C.N.D.C.)
| | - Ivo Driesser
- From the Division of Cardiovascular Imaging, Department of Radiology and Radiological Science (J.V.S., U.J.S., A.W.K., C.N.D.C., F.G.M.) and Division of Cardiology, Department of Medicine (U.J.S.), Medical University of South Carolina, 25 Courtenay Dr, MSC 226, Charleston, SC 29425; Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians-Universität, Munich, Germany (M.R.); Healthcare Division, Computed Tomography, Siemens, Forchheim, Germany (I.D.); Siemens Medical Solutions USA, Malvern, Pa (C.C.); Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (K.M.T., F.G.M.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome "Sapienza"-Polo Pontino, Latina, Italy (C.N.D.C.)
| | - Christian Canstein
- From the Division of Cardiovascular Imaging, Department of Radiology and Radiological Science (J.V.S., U.J.S., A.W.K., C.N.D.C., F.G.M.) and Division of Cardiology, Department of Medicine (U.J.S.), Medical University of South Carolina, 25 Courtenay Dr, MSC 226, Charleston, SC 29425; Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians-Universität, Munich, Germany (M.R.); Healthcare Division, Computed Tomography, Siemens, Forchheim, Germany (I.D.); Siemens Medical Solutions USA, Malvern, Pa (C.C.); Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (K.M.T., F.G.M.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome "Sapienza"-Polo Pontino, Latina, Italy (C.N.D.C.)
| | - Kolja M Thierfelder
- From the Division of Cardiovascular Imaging, Department of Radiology and Radiological Science (J.V.S., U.J.S., A.W.K., C.N.D.C., F.G.M.) and Division of Cardiology, Department of Medicine (U.J.S.), Medical University of South Carolina, 25 Courtenay Dr, MSC 226, Charleston, SC 29425; Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians-Universität, Munich, Germany (M.R.); Healthcare Division, Computed Tomography, Siemens, Forchheim, Germany (I.D.); Siemens Medical Solutions USA, Malvern, Pa (C.C.); Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (K.M.T., F.G.M.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome "Sapienza"-Polo Pontino, Latina, Italy (C.N.D.C.)
| | - Aleksander W Krazinski
- From the Division of Cardiovascular Imaging, Department of Radiology and Radiological Science (J.V.S., U.J.S., A.W.K., C.N.D.C., F.G.M.) and Division of Cardiology, Department of Medicine (U.J.S.), Medical University of South Carolina, 25 Courtenay Dr, MSC 226, Charleston, SC 29425; Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians-Universität, Munich, Germany (M.R.); Healthcare Division, Computed Tomography, Siemens, Forchheim, Germany (I.D.); Siemens Medical Solutions USA, Malvern, Pa (C.C.); Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (K.M.T., F.G.M.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome "Sapienza"-Polo Pontino, Latina, Italy (C.N.D.C.)
| | - Carlo N De Cecco
- From the Division of Cardiovascular Imaging, Department of Radiology and Radiological Science (J.V.S., U.J.S., A.W.K., C.N.D.C., F.G.M.) and Division of Cardiology, Department of Medicine (U.J.S.), Medical University of South Carolina, 25 Courtenay Dr, MSC 226, Charleston, SC 29425; Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians-Universität, Munich, Germany (M.R.); Healthcare Division, Computed Tomography, Siemens, Forchheim, Germany (I.D.); Siemens Medical Solutions USA, Malvern, Pa (C.C.); Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (K.M.T., F.G.M.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome "Sapienza"-Polo Pontino, Latina, Italy (C.N.D.C.)
| | - Felix G Meinel
- From the Division of Cardiovascular Imaging, Department of Radiology and Radiological Science (J.V.S., U.J.S., A.W.K., C.N.D.C., F.G.M.) and Division of Cardiology, Department of Medicine (U.J.S.), Medical University of South Carolina, 25 Courtenay Dr, MSC 226, Charleston, SC 29425; Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians-Universität, Munich, Germany (M.R.); Healthcare Division, Computed Tomography, Siemens, Forchheim, Germany (I.D.); Siemens Medical Solutions USA, Malvern, Pa (C.C.); Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany (K.M.T., F.G.M.); and Department of Radiological Sciences, Oncology and Pathology, University of Rome "Sapienza"-Polo Pontino, Latina, Italy (C.N.D.C.)
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Evaluation of a high iodine delivery rate in combination with low tube current for dose reduction in pulmonary computed tomography angiography. J Thorac Imaging 2015; 29:293-7. [PMID: 25100138 DOI: 10.1097/rti.0000000000000099] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The present study evaluates the combination of a high iodine delivery rate with a low tube current-time product for pulmonary computed tomography angiography (CTA). MATERIALS AND METHODS One-hundred nineteen consecutive patients undergoing pulmonary CTA for suspected pulmonary embolism were included and imaged on a 128-row computed tomography scanner at 100 kVp using highly concentrated contrast material (85 mL Iomeprol; 400 mg iodine/mL). The protocol entailed a flow rate of 5 mL/s and 90 mAs for group A, 3.5 mL/s and 135 mAs for group B, 5 mL/s and 135 mAs for group C, and 3.5 mL/s and 90 mAs for group D. Signal-to-noise ratio and contrast-to-noise ratio (CNR) were determined for the pulmonary artery. Subjective image quality (IQ) was rated on a 5-point scale (1=nondiagnostic IQ to 5=excellent IQ). RESULTS CNR did not differ significantly between groups A (43.7±27.7), B (34.5±17.9), and C (38.9±13.8), as well as between groups B and D (29.9±11.2). CNR was higher in groups A and C than in group D (P<0.02). Subjective IQ was higher in group A than in groups B and D (P<0.05). Subjective IQ was significantly higher in group A compared with group D (P=0.026) and in group C compared with group D (P=0.007). CONCLUSIONS A high iodine delivery rate permits dose reduction in pulmonary CTA and can be recommended in patients with suspected pulmonary embolism.
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Lv P, Liu J, Zhang R, Jia Y, Gao J. Combined Use of Automatic Tube Voltage Selection and Current Modulation with Iterative Reconstruction for CT Evaluation of Small Hypervascular Hepatocellular Carcinomas: Effect on Lesion Conspicuity and Image Quality. Korean J Radiol 2015; 16:531-40. [PMID: 25995682 PMCID: PMC4435983 DOI: 10.3348/kjr.2015.16.3.531] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 01/15/2015] [Indexed: 11/15/2022] Open
Abstract
Objective To assess the lesion conspicuity and image quality in CT evaluation of small (≤ 3 cm) hepatocellular carcinomas (HCCs) using automatic tube voltage selection (ATVS) and automatic tube current modulation (ATCM) with or without iterative reconstruction. Materials and Methods One hundred and five patients with 123 HCC lesions were included. Fifty-seven patients were scanned using both ATVS and ATCM and images were reconstructed using either filtered back-projection (FBP) (group A1) or sinogram-affirmed iterative reconstruction (SAFIRE) (group A2). Forty-eight patients were imaged using only ATCM, with a fixed tube potential of 120 kVp and FBP reconstruction (group B). Quantitative parameters (image noise in Hounsfield unit and contrast-to-noise ratio of the aorta, the liver, and the hepatic tumors) and qualitative visual parameters (image noise, overall image quality, and lesion conspicuity as graded on a 5-point scale) were compared among the groups. Results Group A2 scanned with the automatically chosen 80 kVp and 100 kVp tube voltages ranked the best in lesion conspicuity and subjective and objective image quality (p values ranging from < 0.001 to 0.004) among the three groups, except for overall image quality between group A2 and group B (p = 0.022). Group A1 showed higher image noise (p = 0.005) but similar lesion conspicuity and overall image quality as compared with group B. The radiation dose in group A was 19% lower than that in group B (p = 0.022). Conclusion CT scanning with combined use of ATVS and ATCM and image reconstruction with SAFIRE algorithm provides higher lesion conspicuity and better image quality for evaluating small hepatic HCCs with radiation dose reduction.
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Affiliation(s)
- Peijie Lv
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province 450052, China
| | - Jie Liu
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province 450052, China
| | - Rui Zhang
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province 450052, China
| | - Yan Jia
- Siemens Healthcare China, Beijing 100102, China
| | - Jianbo Gao
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province 450052, China
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Song JS, Choi EJ, Kim EY, Kwak HS, Han YM. Attenuation-based automatic kilovoltage selection and sinogram-affirmed iterative reconstruction: effects on radiation exposure and image quality of portal-phase liver CT. Korean J Radiol 2015; 16:69-79. [PMID: 25598675 PMCID: PMC4296279 DOI: 10.3348/kjr.2015.16.1.69] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 10/19/2014] [Indexed: 11/20/2022] Open
Abstract
Objective To compare the radiation dose and image quality between standard-dose CT and a low-dose CT obtained with the combined use of an attenuation-based automatic kilovoltage (kV) selection tool (CARE kV) and sinogram-affirmed iterative reconstruction (SAFIRE) for contrast-enhanced CT examination of the liver. Materials and Methods We retrospectively reviewed 67 patients with chronic liver disease in whom both, standard-dose CT with 64-slice multidetector-row CT (MDCT) (protocol A), and low-dose CT with 128-slice MDCT using CARE kV and SAFIRE (protocol B) were performed. Images from protocol B during the portal phase were reconstructed using either filtered back projection or SAFIRE with 5 different iterative reconstruction (IR) strengths. We performed qualitative and quantitative analyses to select the appropriate IR strength. Reconstructed images were then qualitatively and quantitatively compared with protocol A images. Results Qualitative and quantitative analysis of protocol B demonstrated that SAFIRE level 2 (S2) was most appropriate in our study. Qualitative and quantitative analysis comparing S2 images from protocol B with images from protocol A, showed overall good diagnostic confidence of S2 images despite a significant radiation dose reduction (47% dose reduction, p < 0.001). Conclusion Combined use of CARE kV and SAFIRE allowed significant reduction in radiation exposure while maintaining image quality in contrast-enhanced liver CT.
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Affiliation(s)
- Ji Soo Song
- Department of Radiology, Chonbuk National University Medical School and Hospital, Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 561-712, Korea
| | - Eun Jung Choi
- Department of Radiology, Chonbuk National University Medical School and Hospital, Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 561-712, Korea
| | - Eun Young Kim
- Department of Radiology, Chonbuk National University Medical School and Hospital, Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 561-712, Korea
| | - Hyo Sung Kwak
- Department of Radiology, Chonbuk National University Medical School and Hospital, Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 561-712, Korea
| | - Young Min Han
- Department of Radiology, Chonbuk National University Medical School and Hospital, Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 561-712, Korea
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Sun H, Xue HD, Jin ZY, Wang X, Chen Y, He YL, Zhang DM, Zhu L. Non-enhanced Low-tube-voltage High-pitch Dual-source Computed Tomography with Sinogram Affirmed Iterative Reconstruction Algorithm of the Abdomen and Pelvis. ACTA ACUST UNITED AC 2014; 29:214-20. [DOI: 10.1016/s1001-9294(14)60073-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Dindyal S, Rahman S, Kyriakides C. Review of the Use of Ionizing Radiation in Endovascular Aneurysm Repair. Angiology 2014; 66:607-12. [PMID: 25225195 DOI: 10.1177/0003319714548564] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Endovascular repair for aortic aneurysm (EVAR) is rapidly increasing in popularity. The nature of this intervention requires significant exposure to ionizing radiation both during the procedure and for postoperative surveillance, generally in the form of computed tomography. Here the authors review the literature for radiation exposure during EVAR, both for the patient and the physician.
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Affiliation(s)
- S Dindyal
- Academic department of circulatory sciences, Vascular and Endovascular Surgery, Barts and The London NHS Trust, The Royal London Hospital, Whitechappel, London, United Kingdom
| | - S Rahman
- Academic department of circulatory sciences, Vascular and Endovascular Surgery, Barts and The London NHS Trust, The Royal London Hospital, Whitechappel, London, United Kingdom
| | - C Kyriakides
- Academic department of circulatory sciences, Vascular and Endovascular Surgery, Barts and The London NHS Trust, The Royal London Hospital, Whitechappel, London, United Kingdom
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Hybrid iterative reconstruction technique for liver CT scans for image noise reduction and image quality improvement: evaluation of the optimal iterative reconstruction strengths. Radiol Med 2014; 120:259-67. [PMID: 25168773 DOI: 10.1007/s11547-014-0441-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 03/19/2014] [Indexed: 12/15/2022]
Abstract
PURPOSE This study sought to investigate the effect of the hybrid iterative reconstruction (IR) algorithm (iDose, Philips Healthcare) on the improvement of image quality of computed tomography (CT) scans of the liver and determine the appropriate level of IR strength for clinical use. MATERIALS AND METHODS A total of 75 patients (41 men and 34 women; mean age, 59.5 years) with a primary abdominal malignancy who underwent two-phase liver CT scans for the work-up of their liver metastases, were included in this study. The CT images during the portal phase were reconstructed using either filtered back projection (FBP) or the hybrid IR algorithm with six different levels of IR strengths. The signal-to-noise ratio of the liver (SNR(liver)) and the contrast-to-noise ratio of the portal vein to muscle (CNR(pv to m)) were measured. For qualitative analysis, image noise, visibility of small intrahepatic vascular structures, beam-hardening artefact, lesion conspicuity, and overall image quality were graded by two radiologists. RESULTS Quantitative analysis demonstrated that image noise was significantly reduced along with the increasing level of iDose and that the values of SNR(liver) and CNR(pv to m) were significantly better with iDose than those of FBP images. Qualitative assessment also showed significantly better results with iDose compared with FBP (p < 0.05) and the parameters for subjective image quality were highest with iDose level 4. CONCLUSIONS The hybrid IR technique is able to reduce image noise and to provide better image quality than FBP, and an intermediate strength of iDose (level 4) provided the highest quality images.
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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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Krazinski AW, Meinel FG, Schoepf UJ, Silverman JR, Canstein C, De Cecco CN, Geyer LL. Reduced radiation dose and improved image quality at cardiovascular CT angiography by automated attenuation-based tube voltage selection: intra-individual comparison. Eur Radiol 2014; 24:2677-84. [PMID: 25052076 DOI: 10.1007/s00330-014-3312-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 05/14/2014] [Accepted: 07/03/2014] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To evaluate the effect of automated tube voltage selection on radiation dose and image quality at cardiovascular CT angiography (CTA). METHODS We retrospectively analysed paired studies in 72 patients (41 male, 60.5 ± 16.5 years), who had undergone CTA acquisitions of the heart or aorta both before and after the implementation of an automated x-ray tube voltage selection algorithm (ATVS). All other parameters were kept identical between the two acquisitions. Subjective image quality (IQ) was rated and objective IQ was measured by image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and figure of merit (FOM). Image quality parameters and effective dose were compared between acquisitions. RESULTS Overall subjective image quality improved with the percentage of cases scored as adequate or higher increasing from 79 % to 92 % after implementation of ATVS (P = 0.03). SNR (14.1 ± 5.9, 15.7 ± 6.1, P = 0.009), CNR (11.6 ± 5.3, 13.2 ± 5.6, P = 0.011), and FOM (19.9 ± 23.3, 43.8 ± 51.1, P < 0.001) were significantly higher after implementation of ATVS. Mean image noise (24.1 ± 8.4 HU, 22.7 ± 7.1 HU, P = 0.048) and mean effective dose (10.6 ± 5.9 mSv, 8.8 ± 5.0 mSv, P = 0.003) were significantly lower after implementation of ATVS. CONCLUSIONS Automated tube voltage selection can operator-independently optimize cardiovascular CTA image acquisition parameters with improved image quality at reduced dose. KEY POINTS • Automatic tube voltage selection optimizes tube voltage for each individual patient. • In this population, overall radiation dose decreased while image quality improved. • This tool may become valuable for improving dose/quality ratio.
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Affiliation(s)
- Aleksander W Krazinski
- Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, MSC 226 25 Courtenay Drive, Charleston, SC, 29425, USA
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Ibrahim M, Parmar H, Christodoulou E, Mukherji S. Raise the bar and lower the dose: current and future strategies for radiation dose reduction in head and neck imaging. AJNR Am J Neuroradiol 2014; 35:619-24. [PMID: 23449649 DOI: 10.3174/ajnr.a3473] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARY Technologic advances in CT have generated a dramatic increase in the number of CT studies, with a resultant increase in the radiation dose related to CT scanning. Such increase in radiation dose is becoming a concern for the radiology community, especially with increasing public awareness of the dose burden related to examinations. To cope with the increase in CT-related radiation exposure, it is becoming necessary to optimize CT imaging protocols and apply radiation dose reduction techniques to ensure the best imaging with the lowest radiation dose.
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Affiliation(s)
- M Ibrahim
- From the University of Michigan Health System, Ann Arbor, Michigan
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Assessment of a model-based, iterative reconstruction algorithm (MBIR) regarding image quality and dose reduction in liver computed tomography. Invest Radiol 2014; 48:598-606. [PMID: 23511193 DOI: 10.1097/rli.0b013e3182899104] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVES The purpose of this study was to assess the image quality of half-dose (HD) liver computed tomography (CT) using a model-based iterative reconstruction algorithm (MBIR) compared with reference dose (RD) using filtered back projection (FBP) and the HD CT images using FBP and adaptive statistical iterative reconstruction (ASIR). MATERIALS AND METHODS A total of 103 patients suspected of having liver metastases underwent liver CT including HD portal venous phase imaging. Among these patients, 73 had undergone RD liver CT reconstructed using FBP, and the HD portal phase CT scans were separately reconstructed using FBP and MBIR. For the other 30 patients, the HD CT images were reconstructed using FBP, ASIR, and MBIR. The CT attenuation coefficients and the mean image noise of various sites, including the liver, the aorta, the main portal vein (MPV), and the subcutaneous fat, were measured, and the contrast-to-noise ratios (CNRs) of the metastatic lesion to the liver and the MPV to the liver were calculated. Two radiologists reviewed each image set with regard to image noise, image quality, lesion conspicuity, and diagnostic acceptability. RESULTS Compared with RD CT, there was a 46.1% decrease in CT dose index volume with HD CT. Image noise was significantly lower in the HD images reconstructed with MBIR than in both the HD FBP images and the RD FBP images (P < 0.001). Compared with the RD FBP and HD FBP images, the CNRs of the metastatic lesion to the liver and the MPV to the liver were higher in the HD MBIR images (P < 0.001). Despite the presence of the unique whirling artifacts of the MBIR images, the HD MBIR images were of good to excellent quality and were not inferior to RD FBP images regarding the lesion conspicuity, the image quality, and the diagnostic acceptability (P > 0.05). Half-dose MBIR also showed less image noise, higher CNRs, and superior image quality compared with HD ASIR (P < 0.001). CONCLUSIONS The HD MBIR images showed less noise, higher CNR, and better image quality than the HD ASIR and HD FBP images did; they also provided less image noise, higher CNR, and similar image quality compared with those of RD FBP images.
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The Emergence of Ultra-Low–Dose Computed Tomography and the Impending Obsolescence of the Plain Radiograph? Can Assoc Radiol J 2013; 64:314-8. [DOI: 10.1016/j.carj.2013.09.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 09/25/2013] [Indexed: 11/23/2022] Open
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Effect of x-ray tube parameters and iodine concentration on image quality and radiation dose in cerebral pediatric and adult CT angiography: a phantom study. Invest Radiol 2013; 48:192-9. [PMID: 23344518 DOI: 10.1097/rli.0b013e31827efc17] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES The aim of the present phantom study was to investigate the effect of x-ray tube parameters and iodine concentration on image quality and radiation dose in cerebral computed tomographic (CT) angiographic examinations of pediatric and adult individuals. MATERIALS AND METHODS Four physical anthropomorphic phantoms that represent the average individual as neonate, 1-year-old, 5-year-old, and 10-year-old children and the RANDO phantom that simulates the average adult individual were used. Cylindrical vessels were bored along the brain-equivalent plugs of each physical phantom. To simulate the brain vasculature, vessels of 0.6, 1, 2, and 3 mm in diameter were created. These vessels were filled with contrast medium (CM) solutions at different iodine concentrations, that is, 5.6, 4.2, 2.7, and 1.4 mg I/mL. The phantom heads were scanned at 120, 100, and 80 kV. The applied quality reference tube current-time product values ranged from a minimum of 45 to a maximum of 680. The CT acquisitions were performed on a 16-slice CT scanner using the automatic exposure control system. Image quality was evaluated on the basis of image noise and contrast-to-noise ratio (CNR) between the contrast-enhanced iodinated vessels and the unenhanced regions of interest. Dose reduction was calculated as the percentage difference of the CT dose index value at the quality reference tube current-time product and the CT dose index at the mean modulated tube current-time product. RESULTS Image noise that was measured using the preset tube current-time product settings varied significantly among the different phantoms (P < 0.0001). Hounsfield unit number of iodinated vessels was linearly related to CM concentration (r² = 0.907) and vessel diameter (r² = 0.918). The Hounsfield unit number of iodinated vessels followed a decreasing trend from the neonate phantom to the adult phantom at all kilovoltage settings. For the same image noise level, a CNR improvement of up to 69% and a dose reduction of up to 61% may be achieved when CT acquisition is performed at 80 kV compared with 120 kV. For the same CNR, a reduction by 25% of the administered CM concentration may be achieved when CT acquisition is performed at 80 kV compared with 120 kV. CONCLUSIONS In cerebral CT angiographic studies, appropriate adjustment of the preset tube current-time product settings is required to achieve the same image noise level among participants of different age. Cerebral CT angiography at 80 kV significantly improves CNR and significantly reduces radiation dose. Moreover, at 80 kV, a considerable reduction of the administered amount of the CM may be reached, thus reducing potential risks for contrast-induced nephropathy.
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Schindera S, Winklehner A, Alkadhi H, Goetti R, Fischer M, Gnannt R, Szucs-Farkas Z. Effect of automatic tube voltage selection on image quality and radiation dose in abdominal CT angiography of various body sizes: A phantom study. Clin Radiol 2013; 68:e79-86. [DOI: 10.1016/j.crad.2012.10.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 10/03/2012] [Accepted: 10/08/2012] [Indexed: 10/27/2022]
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Comparison of Multidetector Computed Tomography Angiography and Cholangiography Performed at 80 and 120 kVp in Live Liver Donors. J Comput Assist Tomogr 2013; 37:443-9. [DOI: 10.1097/rct.0b013e318283bb5c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Contrast-to-noise ratio and low-contrast object resolution on full- and low-dose MDCT: SAFIRE versus filtered back projection in a low-contrast object phantom and in the liver. AJR Am J Roentgenol 2012; 199:8-18. [PMID: 22733888 DOI: 10.2214/ajr.11.7421] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE The purpose of this article is to evaluate the effect of sinogram-affirmed iterative reconstruction (SAFIRE) on contrast-to-noise ratio (CNR) compared with filtered back projection (FBP) and to determine whether SAFIRE improves low-contrast object detection or conspicuity in a low-contrast object phantom and in the liver on full- and low-dose examinations. SUBJECTS AND METHODS A low-contrast object phantom was scanned at 100%, 70%, 50%, and 30% dose using a single-source made of a dual-source MDCT scanner, with the raw data reconstructed with SAFIRE and FBP. Unenhanced liver CT scans in 22 patients were performed using a dual-source MDCT. The raw data from both tubes (100% dose) were reconstructed using FBP, and data from one tube (50% dose) were reconstructed using both FBP and SAFIRE. CNR was measured in the phantom and in the liver. Noise, contrast, and CNR were compared using paired Student t tests. Six readers assessed sphere detection and conspicuity in the phantom and liver-inferior vena cava conspicuity in the patient data. The phantom and patient data were assessed using multiple-variable logistic regression. RESULTS The phantom at 70% and 50% doses with SAFIRE had decreased noise and increased CNR compared with the 100% dose with FBP. In the liver, the mean CNR improvement at 50% dose with SAFIRE compared with FBP was 31.4% and 88% at 100% and 50% doses, respectively (p < 0.001). Sphere object detection and conspicuity improved with SAFIRE (p < 0.001). However, smaller spheres were obscured on both FBP and SAFIRE images at lower doses. Liver-vessel conspicuity improved with SAFIRE over 50%-dose FBP in 67.4% of cases (p < 0.001), and versus 100%-dose FBP, improved in 38.6% of cases (p = 0.085). As a predictor for detection, CNR alone had a discriminatory ability (c-index, 0.970) similar to that of the model that analyzed dose, lesion size, attenuation difference, and reconstruction technique (c-index, 0.978). CONCLUSION Lower dose scans reconstructed with SAFIRE have a higher CNR. The ability of SAFIRE to improve low-contrast object detection and conspicuity depends on the radiation dose level. At low radiation doses, low-contrast objects are invisible, regardless of reconstruction technique.
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Desai GS, Uppot RN, Yu EW, Kambadakone AR, Sahani DV. Impact of iterative reconstruction on image quality and radiation dose in multidetector CT of large body size adults. Eur Radiol 2012; 22:1631-40. [PMID: 22527370 DOI: 10.1007/s00330-012-2424-3] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 01/15/2012] [Accepted: 02/11/2012] [Indexed: 01/27/2023]
Abstract
OBJECTIVE To compare image quality and radiation dose using Adaptive Statistical Iterative Reconstruction (ASiR) and Filtered Back Projection (FBP) in patients weighing ≥ 91 kg. METHODS In this Institution Review Board-approved retrospective study, single-phase contrast-enhanced abdominopelvic CT examinations of 100 adults weighing ≥ 91 kg (mean body weight: 107.6 ± 17.4 kg range: 91-181.9 kg) with (1) ASiR and (2) FBP were reviewed by two readers in a blinded fashion for subjective measures of image quality (using a subjective standardized numerical scale and objective noise) and for radiation exposure. Imaging parameters and radiation dose results of the two techniques were compared within weight and BMI sub-categories. RESULTS All examinations were found to be of adequate quality. Both subjective (mean = 1.4 ± 0.5 vs. 1.6 ± 0.6, P < 0.05) and objective noise (13.0 ± 3.2 vs.19.5 ± 5.7, P < 0.0001) were lower with ASiR. Average radiation dose reduction of 31.5 % was achieved using ASiR (mean CTDIvol. ASiR: 13.5 ± 7.3 mGy; FBP: 19.7 ± 9.0 mGy, P < 0.0001). Other measures of image quality were comparable between the two techniques. Trends for all parameters were similar in patients across weight and BMI sub-categories. CONCLUSION In obese individuals, abdominal CT images reconstructed using ASiR provide diagnostic images with reduced image noise at lower radiation dose. KEY POINTS • CT images in obese adults are noisy, even with high radiation dose. • Newer iterative reconstruction techniques have theoretical advantages in obese patients. • Adaptive statistical iterative reconstruction should reduce image noise and radiation dose. • This has been proven in abdominopelvic CT images of obese patients.
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Affiliation(s)
- Gaurav S Desai
- Department of Abdominal Imaging and Intervention, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, White 270, Boston, MA 02114, USA
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Hur S, Lee JM, Kim SJ, Park JH, Han JK, Choi BI. 80-kVp CT using Iterative Reconstruction in Image Space algorithm for the detection of hypervascular hepatocellular carcinoma: phantom and initial clinical experience. Korean J Radiol 2012; 13:152-64. [PMID: 22438682 PMCID: PMC3303898 DOI: 10.3348/kjr.2012.13.2.152] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 10/14/2011] [Indexed: 12/27/2022] Open
Abstract
Objective To investigate whether the low-tube-voltage (80-kVp), intermediate-tube-current (340-mAs) MDCT using the Iterative Reconstruction in Image Space (IRIS) algorithm improves lesion-to-liver contrast at reduced radiation dosage while maintaining acceptable image noise in the detection of hepatocellular carcinomas (HCC) in thin (mean body mass index, 24 ± 0.4 kg/m2) adults. Subjects and Methods A phantom simulating the liver with HCC was scanned at 50-400 mAs for 80, 100, 120 and 140-kVp. In addition, fifty patients with HCC who underwent multiphasic liver CT using dual-energy (80-kVp and 140-kVp) arterial scans were enrolled. Virtual 120-kVP scans (protocol A) and 80-kVp scans (protocol B) of the late arterial phase were reconstructed with filtered back-projection (FBP), while corresponding 80-kVp scans were reconstructed with IRIS (protocol C). Contrast-to-noise ratio (CNR) of HCCs and abdominal organs were assessed quantitatively, whereas lesion conspicuity, image noise, and overall image quality were assessed qualitatively. Results IRIS effectively reduced image noise, and yielded 29% higher CNR than the FBP at equivalent tube voltage and current in the phantom study. In the quantitative patient study, protocol C helped improve CNR by 51% and 172% than protocols A and B (p < 0.001), respectively, at equivalent radiation dosage. In the qualitative study, protocol C acquired the highest score for lesion conspicuity albeit with an inferior score to protocol A for overall image quality (p < 0.001). Mean effective dose was 2.63-mSv with protocol A and 1.12-mSv with protocols B and C. Conclusion CT using the low-tube-voltage, intermediate-tube-current and IRIS help improve lesion-to-liver CNR of HCC in thin adults during the arterial phase at a lower radiation dose when compared with the standard technique using 120-kVp and FBP.
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Affiliation(s)
- Saebeom Hur
- Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
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Variation in Tube Voltage for Adult Neck MDCT: Effect on Radiation Dose and Image Quality. AJR Am J Roentgenol 2012; 198:621-7. [DOI: 10.2214/ajr.11.6831] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Van der Molen AJ, Joemai RMS, Geleijns J. Performance of longitudinal and volumetric tube current modulation in a 64-slice CT with different choices of acquisition and reconstruction parameters. Phys Med 2011; 28:319-26. [PMID: 22061446 DOI: 10.1016/j.ejmp.2011.10.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 10/08/2011] [Accepted: 10/11/2011] [Indexed: 10/15/2022] Open
Abstract
Aim of the study was to evaluate the performance of a tube current modulation (TCM) system ((SURE)Exposure 3D). On a 64 detector-row CT scanner (Aquilion 64, Toshiba), performance of fixed tube current, longitudinal TCM, and volumetric TCM acquisitions were assessed. A homogeneous cone-shaped phantom and an anthropomorphic phantom were used. Tube current and noise profiles were quantitatively analysed by box and whisker plots when phantom size, acquisition, and reconstruction parameters were varied. At similar median noise, fixed tube current scanning showed a noise range of 16.8-38.3 HU, while longitudinal TCM showed a range of 19.4-31.4 HU and volumetric TCM showed an even lower range of 20.7-28.7 HU. When acquisitions resulting in similar image quality (noise) were compared, the use of volumetric compared to longitudinal TCM resulted in a variable radiation dose reduction up to 6.6%. In conclusion, (SURE)Exposure 3D resulted in more uniform image quality at a lower dose. Volumetric TCM shows improved results over longitudinal TCM.
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Affiliation(s)
- Aart J Van der Molen
- Department of Radiology C-2S, Leiden University Medical Center, Albinusdreef 2, NL-2333 ZA Leiden, The Netherlands.
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Modica MJ, Kanal KM, Gunn ML. The obese emergency patient: imaging challenges and solutions. Radiographics 2011; 31:811-23. [PMID: 21571658 DOI: 10.1148/rg.313105138] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The dramatic rise in the prevalence of obesity among children and adults in the United States over the last several decades has brought several new challenges to the delivery of healthcare. The increased utilization of and dependence on imaging for accurate and timely diagnosis has placed the radiology department in a unique position in the provision of care for the obese emergency patient. Radiology practices must be cognizant of the imaging challenges presented by the obese patient and adjust their imaging algorithms accordingly to optimize all types of diagnostic studies. The article systematically reviews common pitfalls and offers methods to improve image quality when using radiography, ultrasonography, and computed tomography to image the obese patient population.
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Affiliation(s)
- Michael J Modica
- Department of Radiology, University of Washington, 325 Ninth Ave, Box 359728, Seattle, WA 98104-2499, USA
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Performance Assessment of Four 64-Slice Computed Tomographic Devices for a Typical Clinical Protocol. J Comput Assist Tomogr 2011; 35:57-64. [DOI: 10.1097/rct.0b013e3181f124fe] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Treier R, Aroua A, Verdun FR, Samara E, Stuessi A, Trueb PR. Patient doses in CT examinations in Switzerland: implementation of national diagnostic reference levels. RADIATION PROTECTION DOSIMETRY 2010; 142:244-254. [PMID: 20926508 DOI: 10.1093/rpd/ncq279] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Diagnostic reference levels (DRLs) were established for 21 indication-based CT examinations for adults in Switzerland. One hundred and seventy-nine of 225 computed tomography (CT) scanners operated in hospitals and private radiology institutes were audited on-site and patient doses were collected. For each CT scanner, a correction factor was calculated expressing the deviation of the measured weighted computed tomography dose index (CTDI) to the nominal weighted CTDI as displayed on the workstation. Patient doses were corrected by this factor providing a realistic basis for establishing national DRLs. Results showed large variations in doses between different radiology departments in Switzerland, especially for examinations of the petrous bone, pelvis, lower limbs and heart. This indicates that the concept of DRLs has not yet been correctly applied for CT examinations in clinical routine. A close collaboration of all stakeholders is mandatory to assure an effective radiation protection of patients. On-site audits will be intensified to further establish the concept of DRLs in Switzerland.
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Affiliation(s)
- R Treier
- Radiation Protection Division, Federal Office of Public Health, 3003 Bern, Switzerland.
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Schindera S, Nauer C, Treier R, Trueb P, von Allmen G, Vock P, Szucs-Farkas Z. Strategien zur Reduktion der CT-Strahlendosis. Radiologe 2010; 50:1120, 1122-7. [DOI: 10.1007/s00117-010-2053-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Gunn MLD, Kohr JR. State of the art: technologies for computed tomography dose reduction. Emerg Radiol 2009; 17:209-18. [DOI: 10.1007/s10140-009-0850-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Accepted: 10/29/2009] [Indexed: 02/08/2023]
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