Using 100- instead of 120-kVp computed tomography to diagnose pulmonary embolism almost halves the radiation dose with preserved diagnostic quality

2010 ◽  
Vol 51 (3) ◽  
pp. 260-270 ◽  
Author(s):  
Peter Björkdahl ◽  
Ulf Nyman
Keyword(s):  
Computed Tomography ◽  
Pulmonary Embolism ◽  
Image Quality ◽  
Radiation Dose ◽  
Effective Dose ◽  
Ct Number ◽  
Subjective Image Quality ◽  
Diagnostic Quality ◽  
X Ray ◽  
Tube Potential

Background: Concern has been raised regarding the mounting collective radiation doses from computed tomography (CT), increasing the risk of radiation-induced cancers in exposed populations. Purpose: To compare radiation dose and image quality in a chest phantom and in patients for the diagnosis of pulmonary embolism (PE) at 100 and 120 peak kilovoltage (kVp) using 16-multichannel detector computed tomography (MDCT). Material and Methods: A 20-ml syringe containing 12 mg I/ml was scanned in a chest phantom at 100/120 kVp and 25 milliampere seconds (mAs). Consecutive patients underwent 100 kVp ( n = 50) and 120 kVp ( n = 50) 16-MDCT using a “quality reference” effective mAs of 100, 300 mg I/kg, and a 12-s injection duration. Attenuation (CT number), image noise (1 standard deviation), and contrast-to-noise ratio (CNR; fresh clot = 70 HU) of the contrast medium syringe and pulmonary arteries were evaluated on 3-mm-thick slices. Subjective image quality was assessed. Computed tomography dose index (CTDIvol) and dose–length product (DLP) were presented by the CT software, and effective dose was estimated. Results: Mean values in the chest phantom and patients changed as follows when X-ray tube potential decreased from 120 to 100 kVp: attenuation +23% and +40%, noise +38% and +48%, CNR −6% and 0%, and CTDIvol −38% and −40%, respectively. Mean DLP and effective dose in the patients decreased by 42% and 45%, respectively. Subjective image quality was excellent or adequate in 49/48 patients at 100/120 kVp. No patient with a negative CT had any thromboembolism diagnosed during 3-month follow-up. Conclusion: By reducing X-ray tube potential from 120 to 100 kVp, while keeping all other scanning parameters unchanged, the radiation dose to the patient may be almost halved without deterioration of diagnostic quality, which may be of particular benefit in young individuals.

scholarly journals Low Dose versus Standard Single Heartbeat Acquisition Coronary Computed Tomography Angiography

2018 ◽  
Vol 8 ◽  
pp. 52
Author(s):  
Ernesto Di Cesare ◽  
Alessandra Di Sibio ◽  
Antonio Gennarelli ◽  
Margherita Di Luzio ◽  
Ines Casazza ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Comparative Analysis ◽  
Image Quality ◽  
Radiation Dose ◽  
Effective Dose ◽  
Computed Tomography Angiography ◽  
Coronary Computed Tomography Angiography ◽  
Ct Scanner ◽  
Diagnostic Quality ◽  
Coronary Computed Tomography

Purpose: The aim of this study was to compare image quality and mean radiation dose between two groups of patients undergoing coronary computed tomography angiography (CCTA) using a 640-slice CT scanner with two protocols with different noise level thresholds expressed as standard deviation (SD). Materials and Methods: Two-hundred and sixty-eight patients underwent a CCTA with 640 slice CT scanner. In the experimental group (135 patients), an SD 51 protocol was employed; in the control group (133 patients), an SD 33 protocol was used. Mean effective dose and image quality with both objective and subjective measures were assessed. Image quality was subjectively assessed using a five-point scoring system. Segments scoring 2, 3, and 4 were considered having diagnostic quality, while segments scoring 0 and 1 were considered having nondiagnostic quality. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) between the two groups as well as the effective radiation dose (ED) was finally assessed. Results: Comparative analysis considering diagnostic quality (2, 3, and 4 score) and nondiagnostic (score 0 and 1) quality demonstrated that image quality of SD 51 group is not significantly lower than that of S33 group. The noise was significantly higher in the SD 51 group than in the SD 33 group (P < 0.0001). The SNR and CNR were higher in the SD 33 group than in SD 51 group (P < 0.0001). Mean effective dose was 49% lower in the SD 51 group than in SD 33 group; indeed mean effective dose was 1.43 mSv ± 0.67 in the SD 51 group while it was 2.8 mSv ± 0.57 in the SD 33 group. Conclusion: Comparative analysis shows that using a 640-slice CT with a 51 SD protocol, it is possible to reduce the mean radiation dose while maintaining good diagnostic image quality.

scholarly journals A study on the imaging characteristics of Gold nanoparticles as a contrast agent in X-ray computed tomography

2017 ◽  
Vol 23 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Asghar Mesbahi ◽  
Fatemeh Famouri ◽  
Mohammad Johari Ahar ◽  
Maryam Olade Ghaffari ◽  
Seyed Mostafa Ghavami
Keyword(s):  
Computed Tomography ◽  
Contrast Media ◽  
Contrast Agent ◽  
Hounsfield Unit ◽  
Ct Number ◽  
Agent Based ◽  
X Ray ◽  
Imaging Characteristics ◽  
Tube Potential ◽  
X Ray Computed

AbstractAim: In the current study, some imaging characteristics of AuNPs were quantitatively analyzed and compared with two conventional contrast media (CM) including Iodine and Gadolinium by using of a cylindrical phantom.Methods: AuNPs were synthesized with the mean diameter of 16 nm and were equalized to the concentration of 0.5, 1, 2 and 4 mg/mL in the same volumes. A cylindrical phantom resembling the head and neck was fabricated and drilled to contain small tubes filled with Iodine, Gadolinium, and AuNPs as contrast media. The phantom was scanned in different exposure techniques and CT numbers of three studied contrast media inside test tubes were measured in terms of Hounsfield Unit (HU). The imaging parameters of the noise and contrast to noise ratios (CNR) were calculated for all studied CMs.Results: AuNPs showed 128% and 166% higher CT number in comparison with Iodine and Gadolinium respectively. Also, Iodine had a greater CT number than Gadolinium for the same exposure techniques and concentration. The maximum CT number for AuNPs and studied contrast materials was obtained at the highest mAs and the lowest tube potential. The maximum CT number were 1033±11 (HU) for AuNP, 565±10 (HU) for Iodine, 458±11 for Gadolinium. Moreover, the maximum CNRs of 433±117, 203±53, 145±37 were found for AuNPs, Iodine and Gadolinium respectively.Conclusion: The contrast agent based on AuNPs showed higher imaging quality in terms of contrast and noise relative to other iodine and gadolinium based contrast media in X-ray computed tomography. Application of the AuNPs as a contrast medium in x-ray CT is recommended.

Radiation dose reduction in paediatric coronary computed tomography: assessment of effective dose and image quality

2015 ◽  
Vol 26 (7) ◽  
pp. 2030-2038 ◽  
Author(s):  
Bouchra Habib Geryes ◽  
Raphael Calmon ◽  
Diala Khraiche ◽  
Nathalie Boddaert ◽  
Damien Bonnet ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Effective Dose ◽  
Dose Reduction ◽  
Radiation Dose Reduction ◽  
Coronary Computed Tomography

scholarly journals Effect of Lowering Tube Potential and Increase Iodine Concentration of Contrast Medium on Radiation Dose and Image Quality in Computed Tomography Pulmonary Angiography Procedure: A Phantom Study

2021 ◽  
Vol 47 (3) ◽  
pp. 1211-1224
Author(s):  
Justin E Ngaile ◽  
Peter K Msaki ◽  
Evarist M Kahuluda ◽  
Furaha M Chuma ◽  
Jerome M Mwimanzi ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Contrast Medium ◽  
Iodine Concentration ◽  
Pulmonary Angiography ◽  
Computed Tomography Pulmonary Angiography ◽  
Iodinated Contrast ◽  
Tube Potential ◽  
Tube Current

The aim of the study was to examine the effect of lowering tube potential and increase iodine concentration on image quality and radiation dose in computed tomography pulmonary angiography procedure. The pulmonary arteries were simulated by three syringes. The syringes were filled with 1:10 diluted solutions of 300 mg, 350 mg and 370 mg of iodine per millilitre concentration in three water-filled phantoms simulating thin, intermediate and thick patients. The phantoms were scanned at 80 kVp, 110 kVp and 130 kVp and 0.6 second rotation time using a 16 slice computed tomography (CT) scanner. The tube current was either fixed at 80, 100, 200, 250 and 300 mA or automatically adjusted with quality reference tube current-time product (mAsQR). In comparison with 130 kVp, images acquired at 80 kVp and 110 kVp, respectively, showed 76.2% to 99% and 19% to 26% enhancement in CT attenuation of iodinated contrast material. A volume CT dose index (CTDIvol) reduction by 35.3% was attained in small phantom with the use of 80 kVp, while in the medium phantom, a CTDIvol reduction by 29.9% was attained with the use of 110 kVp instead of 130 kVp. In light of the above, lowering tube potential and increase iodinated CM could substantially reduce the dose to small-sized adults and children. Keywords: Angiography; Computed tomography; Low tube potential; Iodinated contrast medium; Radiation dose

scholarly journals Third-generation dual-source computed tomography of the abdomen: comparison of radiation dose and image quality of 80kVp and 80/150kVp with tin filter

2020 ◽  
Author(s):  
Seung Joon Choi ◽  
So Hyun Park ◽  
Seong Ho Park ◽  
Seong Yong Pak ◽  
Jae Won Choi ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Third Generation ◽  
Line Density ◽  
Oncology Patients ◽  
Subjective Image Quality ◽  
Dual Source ◽  
Lesion Conspicuity ◽  
Tin Filter

AbstractObjectiveTo compare the radiation dose, objective and subjective image quality, and diagnostic performances of 80 kVp and 80/150 kVp with tin filter (80/Sn150 kVp) computed tomography (CT) in oncology patients.MethodsOne hundred forty-five consecutive oncology patients who underwent third-generation dual-source dual-energy CT of the abdomen for evaluation of malignant visceral, peritoneal, extraperitoneal, and bone tumor were retrospectively recruited. Two radiologists independently reviewed each observation in 80 kVp CT and 80/Sn150 kVp CT. Modified line-density profile of the tumor and contrast-to-noise ratio (CNR) were measured. Diagnostic confidence, lesion conspicuity, and subjective image quality were calculated and compared between image sets.ResultsModified line-density profile analysis revealed higher attenuation differences between the tumor and the normal tissue in 80 kVp CT than in 80/Sn150 kVp CT (127 vs. 107, P = 0.05). The 80 kVp CT showed increased CNR in the liver (8.0 vs. 7.6) and the aorta (18.9 vs. 16.3) than the 80/Sn150 kVp CT. The 80 kVp CT yielded higher enhancement of organs (4.9 ± 0.2 vs. 4.7 ± 0.4, P < 0.001) and lesion conspicuity (4.9 ± 0.3 vs. 4.8 ± 0.5, P = 0.035) than the 80/Sn150 kVp CT; overall image quality and confidence index were comparable. The effective dose reduced by 45.2% with 80 kVp CT (2.3 mSv ± 0.9) compared to 80/Sn150 kVp CT (4.1 mSv ± 1.5).ConclusionsThe 80 kVp CT performed similar or better than 80/Sn150 kVp CT for abdominal tumor evaluation with 45.2% radiation dose reduction in oncology patients.

scholarly journals Canadian Society of Thoracic Radiology/Canadian Association of Radiologists Best Practice Guidance for Investigation of Acute Pulmonary Embolism, Part 2: Technical Issues and Interpretation Pitfalls

2021 ◽  
pp. 084653712110007
Author(s):  
Elsie T. Nguyen ◽  
Cameron Hague ◽  
Daria Manos ◽  
Brett Memauri ◽  
Carolina Souza ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Pulmonary Embolism ◽  
Image Quality ◽  
Best Practice ◽  
Acute Pulmonary Embolism ◽  
Reporting Quality ◽  
Diagnostic Quality ◽  
Pulmonary Angiogram ◽  
Canadian Association ◽  
Clinical Scenarios

The investigation of acute pulmonary embolism is a common task for radiologists in Canada. Technical image quality and reporting quality must be excellent; pulmonary embolism is a life-threatening disease that should not be missed but overdiagnosis and unnecessary treatment should be avoided. The most frequently performed imaging investigation, computed tomography pulmonary angiogram (CTPA), can be limited by poor pulmonary arterial opacification, technical artifacts and interpretative errors. Image quality can be affected by patient factors (such as body habitus, motion artifact and cardiac output), intravenous (IV) contrast protocols (including the timing, rate and volume of IV contrast administration) and common physics artifacts (including beam hardening). Mimics of acute pulmonary embolism can be seen in normal anatomic structures, disease in non-vascular structures and pulmonary artery filling defects not related to acute pulmonary emboli. Understanding these pitfalls can help mitigate error, improve diagnostic quality and optimize patient outcomes. Dual energy computed tomography holds promise to improve imaging diagnosis, particularly in clinical scenarios where routine CTPA may be problematic, including patients with impaired renal function and patients with altered cardiac anatomy.

scholarly journals Simulated Annealing-Based Image Reconstruction for Patients With COVID-19 as a Model for Ultralow-Dose Computed Tomography

2022 ◽  
Vol 12 ◽  
Author(s):  
Shahzad Ahmad Qureshi ◽  
Aziz Ul Rehman ◽  
Adil Aslam Mir ◽  
Muhammad Rafique ◽  
Wazir Muhammad
Keyword(s):  
Computed Tomography ◽  
Simulated Annealing ◽  
Image Reconstruction ◽  
Image Quality ◽  
Radiation Dose ◽  
Signal To Noise Ratio ◽  
Absolute Error ◽  
Signal To Noise ◽  
X Ray ◽  
Squared Error

The proposed algorithm of inverse problem of computed tomography (CT), using limited views, is based on stochastic techniques, namely simulated annealing (SA). The selection of an optimal cost function for SA-based image reconstruction is of prime importance. It can reduce annealing time, and also X-ray dose rate accompanying better image quality. In this paper, effectiveness of various cost functions, namely universal image quality index (UIQI), root-mean-squared error (RMSE), structural similarity index measure (SSIM), mean absolute error (MAE), relative squared error (RSE), relative absolute error (RAE), and root-mean-squared logarithmic error (RMSLE), has been critically analyzed and evaluated for ultralow-dose X-ray CT of patients with COVID-19. For sensitivity analysis of this ill-posed problem, the stochastically estimated images of lung phantom have been reconstructed. The cost function analysis in terms of computational and spatial complexity has been performed using image quality measures, namely peak signal-to-noise ratio (PSNR), Euclidean error (EuE), and weighted peak signal-to-noise ratio (WPSNR). It has been generalized for cost functions that RMSLE exhibits WPSNR of 64.33 ± 3.98 dB and 63.41 ± 2.88 dB for 8 × 8 and 16 × 16 lung phantoms, respectively, and it has been applied for actual CT-based image reconstruction of patients with COVID-19. We successfully reconstructed chest CT images of patients with COVID-19 using RMSLE with eighteen projections, a 10-fold reduction in radiation dose exposure. This approach will be suitable for accurate diagnosis of patients with COVID-19 having less immunity and sensitive to radiation dose.

Sign in / Sign up

Export Citation Format

Share Document