scholarly journals Radiation Dose Reduction in Preprocedural CT Imaging for TAVI/TAVR Using a Novel 3-Phase Protocol: A Single Institution’s Experience

2020 ◽  
Vol 192 (12) ◽  
pp. 1174-1182 ◽  
Author(s):  
Seyd Shnayien ◽  
Keno Kyrill Bressem ◽  
Nick Lasse Beetz ◽  
Patrick Asbach ◽  
Bernd Hamm ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Aortic Valve ◽  
Radiation Dose ◽  
Phase Variable ◽  
The Novel ◽  
Subjective Image Quality ◽  
Transcatheter Aortic Valve ◽  
Noise Ratio ◽  
Spiral Scan

Purpose To retrospectively investigate the effectiveness of a novel 3-phase protocol for computed tomography (CT) before transcatheter aortic valve implantation/transcatheter aortic valve replacement (TAVI/TAVR) in terms of radiation dose and image quality. Materials and Methods A total of 107 nonrandomized patients (81 ± 7.4 years) scheduled for TAVI/TAVR underwent preprocedural CT on an 80-row CT scanner. 55 patients underwent a combined ECG-synchronized spiral scan of the chest and non-ECG-synchronized spiral scan of the abdomen/pelvis as recommended by the Society of Cardiovascular Computed Tomography (SCCT). 52 patients underwent an updated 3-phase variable helical pitch (vHP3) protocol combining a non-ECG-synchronized spiral scan of the upper thoracic aperture, followed by a prospective ECG-synchronized spiral scan of the heart, and a non-ECG-synchronized abdominal/pelvic spiral scan. The radiation dose was determined from an automatically generated protocol based on the CT dose index (CTDI). Objective image quality in terms of vessel attenuation and image noise was measured, and the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Subjective image quality was evaluated using a 4-point scale and compared for interrater agreement using Cohen’s weighted kappa coefficient (κw). All data were compared and statistically analyzed. Results Use of the novel 3-phase vHP3 protocol reduced the dose-length product (DLP) from 1256.58 ± 619.05 mGy*cm to 790.90 ± 238.15 mGy*cm, reducing the effective dose (E) from 21.36 ± 10.52 mSv to 13.44 ± 4.05 mSv and size-specific dose estimates (SSDE) from 20.85 ± 7.29 mGy to 13.84 ± 2.94 mGy (p < 0.001). There were no significant differences in objective and subjective image quality between the two protocols and between the two readers. Conclusion The novel 3-phase vHP3 protocol significantly reduces the radiation dose of preprocedural TAVI/TAVR CT without a loss of image quality. Key Points:  Citation Format

scholarly journals Computed Tomography Angiography with a 192-slice Dual-source Computed Tomography System: Improvements in Image Quality and Radiation Dose

2016 ◽  
Vol 6 ◽  
pp. 44 ◽  
Author(s):  
Philip V M Linsen ◽  
Adriaan Coenen ◽  
Marisa M Lubbers ◽  
Marcel L Dijkshoorn ◽  
Mohamed Ouhlous ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Heart Rate ◽  
Image Quality ◽  
Radiation Dose ◽  
Computed Tomography Angiography ◽  
Signal To Noise Ratio ◽  
High Pitch ◽  
Subjective Image Quality ◽  
Dual Source ◽  
Noise Ratio

Purpose: This study aims to compare image quality, radiation dose, and the influence of the heart rate on image quality of high-pitch spiral coronary computed tomography angiography (CCTA) using 128-slice (second generation) dual-source CT (DSCT) and a 192-slice DSCT (third generation) scanner. Materials and Methods: Two consecutive cohorts of fifty patients underwent CCTA by high-pitch spiral scan mode using 128 or 192-slice DSCT. The 192-slice DSCT system has a more powerful roentgen tube (2 × 120 kW) that allows CCTA acquisition at lower tube voltages, wider longitudinal coverage for faster table speed (732 m/s), and the use of iterative reconstruction. Objective image quality was measured as the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Subjective image quality was evaluated using a Likert scale. Results: While the effective dose was lower with 192-slice DSCT (1.2 ± 0.5 vs. 0.6 ± 0.3 mSv; P < 0.001), the SNR (18.9 ± 4.3 vs. 11.0 ± 2.9; P < 0.001) and CNR (23.5 ± 4.8 vs. 14.3 ± 4.1; P < 0.001) were superior to 128-slice DSCT. Although patients scanned with 192-slice DSCT had a faster heart rate (59 ± 7 vs. 56 ± 6; P = 0.045), subjective image quality was scored higher (4.2 ± 0.8 vs. 3.0 ± 0.7; P < 0.001) compared to 128-slice DSCT. Conclusions: High-pitch spiral CCTA by 192-slice DSCT provides better image quality, despite a higher average heart rate, at lower radiation doses compared to 128-slice DSCT.

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.

Abstract 17600: Improved Iterative Reconstruction Reduces Artifacts and Results in Larger Measurements of Ileofemoral Artery Size on Computed Tomography in Patients Referred for Transcatheter Aortic Valve Replacement

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Anum Minhas ◽  
Smita Patel ◽  
Ella Kazerooni ◽  
Antonio Conte ◽  
Troy Labounty
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Aortic Valve ◽  
Aortic Valve Replacement ◽  
Valve Replacement ◽  
Iterative Reconstruction ◽  
Transcatheter Aortic Valve Replacement ◽  
Beam Hardening ◽  
Transcatheter Aortic Valve ◽  
Blinded Reader

Background: Computed tomography (CT) is typically used to measure ileofemoral artery size in patients considered for transcatheter aortic valve replacement (TAVR). However, these patients often have significant arterial calcification, which can introduce artifacts and limit measurement accuracy. We hypothesized that improved iterative reconstruction would improve image quality and reduce artifacts, resulting in larger measured size. Methods: We examined 56 patients undergoing CT for possible TAVR, and compared image quality and ileofemoral arterial size between separate reconstructions of the same studies, comparing standard (STD) advanced statistical iterative reconstruction and improved model-based iterative reconstruction (MBIR). A blinded reader identified the sites with the smallest luminal diameter, and provided identical short-axis reformats for both reconstructions. A separate blinded reader graded image quality and made measurements in a random sequence. We compared mean and minimal diameters, image quality (1 poor, 4 excellent), and signal and noise. Results: Mean age was 77 ± 10 years and 54% were male. Table 1 compares measured diameters and image quality between STD and MBIR reconstructions. Between STD and MBIR images, ≥moderate beam-hardening artifacts were observed in 30% (17/56) and 9% (5/56) of patients, respectively (p=0.008); severe artifacts were seen in 23% (13/56) and 5% (3/56) of patients, respectively (p=0.01). Overall image quality of STD and MBIR images was graded as good or excellent in 70% (39/56) and 91% (51/56) of cases, respectively (p=0.008). Conclusion: In patients referred for TAVR, improved iterative reconstruction resulted in higher image quality, fewer beam-hardening artifacts, and larger measurements of ileofemoral artery size.

scholarly journals Influence of a novel deep-learning based reconstruction software on the objective and subjective image quality in low-dose abdominal computed tomography

2021 ◽  
Vol 94 (1117) ◽  
pp. 20200677
Author(s):  
Andrea Steuwe ◽  
Marie Weber ◽  
Oliver Thomas Bethge ◽  
Christin Rademacher ◽  
Matthias Boschheidgen ◽  
...  
Keyword(s):  
Deep Learning ◽  
Image Quality ◽  
Dose Reduction ◽  
Low Dose ◽  
Ct Images ◽  
Image Noise ◽  
The Novel ◽  
Subjective Image Quality ◽  
Image Information ◽  
Noise Ratio

Objectives: Modern reconstruction and post-processing software aims at reducing image noise in CT images, potentially allowing for a reduction of the employed radiation exposure. This study aimed at assessing the influence of a novel deep-learning based software on the subjective and objective image quality compared to two traditional methods [filtered back-projection (FBP), iterative reconstruction (IR)]. Methods: In this institutional review board-approved retrospective study, abdominal low-dose CT images of 27 patients (mean age 38 ± 12 years, volumetric CT dose index 2.9 ± 1.8 mGy) were reconstructed with IR, FBP and, furthermore, post-processed using a novel software. For the three reconstructions, qualitative and quantitative image quality was evaluated by means of CT numbers, noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) in six different ROIs. Additionally, the reconstructions were compared using SNR, peak SNR, root mean square error and mean absolute error to assess structural differences. Results: On average, CT numbers varied within 1 Hounsfield unit (HU) for the three assessed methods in the assessed ROIs. In soft tissue, image noise was up to 42% lower compared to FBP and up to 27% lower to IR when applying the novel software. Consequently, SNR and CNR were highest with the novel software. For both IR and the novel software, subjective image quality was equal but higher than the image quality of FBP-images. Conclusion: The assessed software reduces image noise while maintaining image information, even in comparison to IR, allowing for a potential dose reduction of approximately 20% in abdominal CT imaging. Advances in knowledge: The assessed software reduces image noise by up to 27% compared to IR and 48% compared to FBP while maintaining the image information. The reduced image noise allows for a potential dose reduction of approximately 20% in abdominal imaging.

An open label, prospective, multicenter, non-interventional study of iodixanol 270 mg I/mL for use in individuals undergoing computed tomography angiography in real-world clinical practice

2018 ◽  
Vol 60 (2) ◽  
pp. 177-185
Author(s):  
Xiangying Du ◽  
Bin Lu ◽  
Daoyu Hu ◽  
Bin Song ◽  
Kuncheng Li
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Computed Tomography Angiography ◽  
Pulmonary Arteries ◽  
Open Label ◽  
Tube Voltage ◽  
Effective Radiation Dose ◽  
Noise Ratio

Background Concern about radiation exposure is leading to an increasing interest in low-concentration contrast medium administration. Purpose To evaluate the image quality and safety profile after administration of iodixanol 270 mg I/mL at 100-kVp tube voltage with iterative reconstruction in subjects undergoing computed tomography angiography (CTA). Material and Methods Patients who completed CTA examination using iodixanol 270 mg I/mL and 100-kVp tube voltage along with iterative reconstruction for coronary, aortic, head and neck, renal, or pulmonary arteries were included. Image quality was qualitatively and quantitatively evaluated. Incidence of adverse events (AEs) and adverse drug reactions (ADRs) within seven days and radiation dose were also analyzed. Results A total of 4513 individuals in 42 centers in China were enrolled, among which 4367 were included in efficacy analysis. The mean image quality score was 4.8 ± 0.45 across all arteries (all above 4.6) and 99.7% of the individuals’ images were classified as evaluable. The CT attenuation, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) in the regions of interest (ROIs) were 431.79 ± 99.018, 18.29 ± 11.947, and 28.21 ± 19.535 HU, respectively. Of all the participants, 68 (1.5%) and 65 (1.4%) experienced AEs and ADRs, respectively. No serious AEs or AEs leading to discontinuation occurred. The average effective radiation dose was 3.13 ± 2.550 mSv. Conclusion Iodixanol 270 mg I/mL in combination with 100-kVp tube voltage and iterative reconstruction could be safely applied in CTA and yield high-quality and evaluable images with reduced 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 Effect of Tube Voltage (100 vs. 120 kVp) on Radiation Dose and Image Quality using Prospective Gating 320 Row Multi-detector Computed Tomography Angiography

2013 ◽  
Vol 3 ◽  
pp. 62 ◽  
Author(s):  
Atif N. Khan ◽  
Faisal Khosa ◽  
Waqas Shuaib ◽  
Khurram Nasir ◽  
Ron Blankstein ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Computed Tomography Angiography ◽  
Tube Voltage ◽  
Prospective Gating ◽  
Noise Ratio ◽  
Group 2 ◽  
Multi Detector Computed Tomography ◽  
Group 1

Objectives: The objective of the following study is to evaluate the effect of reducing tube voltage from 120 to 100 kVp using prospective gating 320 row multi-detector computed tomography angiography on image quality and reduction in radiation dose. Materials and Methods: A total of 78 sequential patients were scanned with prospective electrocardiogram gating. A total of 45 patients (Group 1) with mean body mass index (BMI) 29 ± 2 and heart rate (HR) 57 ± 7 beats per minute (BPM) were scanned at 120 kVp. 33 patients (Group 2) with mean BMI 23 ± 3 and HR 58 ± 6 bpm were scanned at 100 kVp. Effective dose was calculated using dose length product and factor (k = 0.014). Quantitative assessment of image quality was calculated by measuring signal to noise ratio (SNR) and contrast to noise ratio (CNR) in the left ventricle and left main coronary artery. Two experienced cardiac radiologists using a three-point ordinal scale assessed subjectively image quality. Results: In Group 1, the median radiation dose was 5.31 mSv (95% confidence interval [CI]: 4.86-6.09) and for Group 2 (P = 0.009) the mean radiation dose was 3.71 mSv (95% CI: 2.76-4.87), representing 30% decrease in radiation dose. In multivariate analyses, adjusting for age, gender, HR, BMI, tube current and scan length, an absolute median reduction of 2.21 mSv (1.13-3.29 mSv) was noted in patients scanned with 100 kVp (P < 0.0001). The quantitative image quality (SNR and CNR) was not statistically significant between the groups. Subjective image quality was rated as good or excellent in 99% of coronary segments for both groups (P value was considered as non-significant). Conclusion: Our study suggests that radiation dose may be lowered from 120 to 100 kVp with preservation of image quality in patient's whose BMI is ≤27.

scholarly journals Comparison of image quality and radiation dose using different pre-ASiR-V and post-ASiR-V levels in coronary computed tomography angiography

2020 ◽  
pp. 1-10
Author(s):  
Yongxia Zhao ◽  
Dongxue Li ◽  
Zhichao Liu ◽  
Xue Geng ◽  
Tianle Zhang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Computed Tomography Angiography ◽  
Coronary Computed Tomography Angiography ◽  
Effective Radiation Dose ◽  
Dose Length Product ◽  
Coronary Computed Tomography ◽  
Significant Difference ◽  
Noise Ratio

OBJECTIVE: To determine the optimal pre-adaptive and post-adaptive level statistical iterative reconstruction V (ASiR-V) for improving image quality and reducing radiation dose in coronary computed tomography angiography (CCTA). METHODS: The study was divided into two parts. In part I, 150 patients for CCTA were prospectively enrolled and randomly divided into 5 groups (A, B, C, D, and E) with progressive scanning from 40% to 80% pre-ASiR-V with 10% intervals and reconstructing with 70% post-ASiR-V. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Subjective image quality was assessed using a 5-point scale. The CT dose index volume (CTDIvol) and dose-length product (DLP) of each patient were recorded and the effective radiation dose (ED) was calculated after statistical analysis by optimizing for the best pre-ASiR-V value with the lowest radiation dose while maintaining overall image quality. In part II, the images were reconstructed with the recommended optimal pre-ASiR-V values in part I (D group) and 40%–90% of post-ASiR-V. The reconstruction group (D group) was divided into 6 subgroups (interval 10%, D0:40% post-ASiR-V, D1:50% post - ASiR-V, D2:60% post-ASiR-V, D3:70% post-ASiR-V, D4:80% post-ASiR-V, and D5:90% post-ASiR-V).The SNR and CNR of D0-D5 subgroups were calculated and analyzed using one-way analysis of variance, and the consistency of the subjective scores used the k test. RESULTS: There was no significant difference in the SNRs, CNRs, and image quality scores among A, B, C, and D groups (P > 0.05). The SNR, CNR, and image quality scores of the E group were lower than those of the A, B, C, and D groups (P < 0.05). The mean EDs in the B, C, and D groups were reduced by 7.01%, 13.37%, and 18.87%, respectively, when compared with that of the A group. The SNR and CNR of the D4–D5 subgroups were higher than the D0-D3 subgroups, and the image quality scores of the D4 subgroups were higher than the other subgroups (P < 0.05). CONCLUSION: The wide-detector combined with 70% pre-ASiR-V and 80% post-ASiR-V significantly reduces the radiation dose of CCTA while maintaining overall image quality as compared with the manufacture’s recommendation of 40% pre-ASiR-V.

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