Three-dimensional cardiac rotational angiography: effective radiation dose and image quality implications

To evaluate the effect of radiation dose reduction on image quality and diagnostic confidence in contrast-enhanced whole-body computed tomography (WBCT) staging. We randomly selected March 2016 for retrospective inclusion of 18 consecutive patients (14 female, 60 ± 15 years) with clinically indicated WBCT staging on the same 3rd generation dual-source CT. Using low-dose simulations, we created data sets with 100, 80, 60, 40, and 20% of the original radiation dose. Each set was reconstructed using filtered back projection (FBP) and Advanced Modeled Iterative Reconstruction (ADMIRE®, Siemens Healthineers, Forchheim, Germany) strength 1–5, resulting in 540 datasets total. ADMIRE 2 was the reference standard for intraindividual comparison. The effective radiation dose was calculated using commercially available software. For comparison of objective image quality, noise assessments of subcutaneous adipose tissue regions were performed automatically using the software. Three radiologists blinded to the study evaluated image quality and diagnostic confidence independently on an equidistant 5-point Likert scale (1 = poor to 5 = excellent). At 100%, the effective radiation dose in our population was 13.3 ± 9.1 mSv. At 20% radiation dose, it was possible to obtain comparably low noise levels when using ADMIRE 5 (p = 1.000, r = 0.29). We identified ADMIRE 3 at 40% radiation dose (5.3 ± 3.6 mSv) as the lowest achievable radiation dose with image quality and diagnostic confidence equal to our reference standard (p = 1.000, r > 0.4). The inter-rater agreement for this result was almost perfect (ICC ≥ 0.958, 95% CI 0.909–0.983). On a 3rd generation scanner, it is feasible to maintain good subjective image quality, diagnostic confidence, and image noise in single-energy WBCT staging at dose levels as low as 40% of the original dose (5.3 ± 3.6 mSv), when using ADMIRE 3.

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Reducing cranial computed tomography effective radiation dose by 30% using adaptive iterative dose reduction

Proceedings of Singapore Healthcare ◽

10.1177/2010105816651655 ◽

2016 ◽

Vol 25 (4) ◽

pp. 230-234

Author(s):

Wai-Yung Yu ◽

Thye Sin Ho ◽

Henry Ko ◽

Wai-Yee Chan ◽

Serene Ong ◽

...

Keyword(s):

Computed Tomography ◽

Image Quality ◽

Radiation Dose ◽

Dose Reduction ◽

Diagnostic Image Quality ◽

Radiation Doses ◽

Effective Radiation Dose ◽

Diagnostic Image ◽

Ct Head ◽

Effective Radiation

Introduction: The use of computed tomography (CT) imaging as a diagnostic modality is increasing rapidly and CT is the dominant contributor to diagnostic medical radiation exposure. The aim of this project was to reduce the effective radiation dose to patients undergoing cranial CT examination, while maintaining diagnostic image quality. Methods: Data from a total of 1003, 132 and 27 patients were examined for three protocols: CT head, CT angiography (CTA), and CT perfusion (CTP), respectively. Following installation of adaptive iterative dose reduction (AIDR) 3D software, tube current was lowered in consecutive cycles, in a stepwise manner and effective radiation doses measured at each step. Results: Baseline effective radiation doses for CT head, CTA and CTP were 1.80, 3.60 and 3.96 mSv, at currents of 300, 280 and 130–150 mA, respectively. Using AIDR 3D and final reduced currents of 160, 190 and 70–100 mA for CT head, CTA and CTP gave effective doses of 1.29, 3.18 and 2.76 mSv, respectively. Conclusion: We demonstrated that satisfactory reductions in the effective radiation dose for CT head (28.3%), CTA (11.6%) and CTP (30.1%) can be achieved without sacrificing diagnostic image quality. We have also shown that iterative reconstruction techniques such as AIDR 3D can be effectively used to help reduce effective radiation dose. The dose reductions were performed within a short period and can be easily achievable, even in busy departments.

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The feasibility of low-concentration contrast and low tube voltage in computed tomography perfusion imaging: an animal study

Bioscience Reports ◽

10.1042/bsr20170977 ◽

2018 ◽

Vol 38 (1) ◽

Cited By ~ 1

Author(s):

Yuning Pan ◽

Aiqin Song ◽

Shizhong Bu ◽

Zhaoqian Chen ◽

Qiuli Huang ◽

...

Keyword(s):

Image Quality ◽

Radiation Dose ◽

Perfusion Imaging ◽

Ct Perfusion ◽

Iodine Intake ◽

Tube Voltage ◽

Effective Radiation Dose ◽

Low Concentration ◽

Low Tube Voltage ◽

Effective Radiation

Aim: To investigate the feasibility of low-concentration contrast (270 mg/ml) together with low tube voltage (80 kV) and adaptive iterative dose reduction (AIDR)-3D reconstruction in liver computed tomography (CT) perfusion imaging. Method: A total of 15 healthy New Zealand rabbits received two CT scans each. The first scan (control) was acquired at 100 kV and 100 mA with iopromide (370 mg/ml), while the second scan (experimental) was acquired at 80 kV and 100 mA with iodixanol (270 mg/ml) 24 h after the first scan. The obtained images were reconstructed with filtered back projection (FBP) and AIDR-3D in the control and experimental groups respectively. The perfusion parameters (hepatic artery perfusion [HAP], portal vein perfusion [PVP], hepatic perfusion index [HPI], and total liver perfusion [TLP]) and image quality (image quality score, average CT value of abdomen aorta, signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR], and figure of merit [FOM]) were compared using a paired t-test or Mann–Whitney U test between the two groups, when appropriate. The effective radiation dose and iodine intake were also recorded and compared. Results: With the exception of the FOM criteria, the image quality and perfusion parameters were not significantly different between the two groups. The effective radiation dose and iodine intake were 38.79% and 27.03% lower respectively, in the experimental group. Conclusion: Low-concentration contrast (iodixanol, 270 mg/ml) together with low tube voltage (80 kV) and AIDR-3D reconstruction help to reduce radiation dose and iodine intake without compromising perfusion parameters and image quality in liver CT perfusion imaging.

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Image quality of low-radiation dose left atrial CT using filtered back projection and an iterative reconstruction algorithm: intra-individual comparison in unselected patients undergoing pulmonary vein isolation

Acta Radiologica ◽

10.1177/0284185117708472 ◽

2017 ◽

Vol 59 (2) ◽

pp. 161-169

Author(s):

Ute Lina Fahlenkamp ◽

Ivan Diaz Ramirez ◽

Moritz Wagner ◽

Carsten Schwenke ◽

Alexander Huppertz ◽

...

Keyword(s):

Image Quality ◽

Radiation Dose ◽

Dual Source Ct ◽

Back Projection ◽

Reconstruction Algorithms ◽

Effective Radiation Dose ◽

Subjective Image Quality ◽

Low Radiation Dose ◽

Dual Source ◽

Effective Radiation

Background Computed tomography (CT) of the left atrium (LA) is performed prior to pulmonary vein isolation (PVI) to improve success of circumferential ablation for atrial fibrillation. The ablation procedure itself exposes patients to substantial radiation doses, therefore radiation dose reduction in pre-ablational imaging is of concern. Purpose To assess and compare diagnostic performance of low-radiation dose preprocedural CT in patients scheduled for PVI using two types of reconstruction algorithms. Material and Methods Forty-six patients (61 ± 10 years) scheduled for PVI were enrolled in this study irrespective of body-mass-index or cardiac rhythm at examination. An electrocardiographically triggered dual-source CT scan was performed. Filtered back projection (FBP) and iterative reconstruction (IR) algorithms were applied. Images were integrated into an electroanatomic mapping (EAM) system. Subjective image quality was scored independently by two readers on a five-point scale for both reconstruction algorithms (1 = excellent to 5 = non-diagnostic). Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and effective radiation dose were calculated. Results Data acquisition and EAM integration were successful in all patients. Median image quality score was 1 for both FBP (quartiles = 1, 1.62; range = 1–3) and IR (quartiles = 1, 1.5; range = 1–3). Mean SNR was 7.61 ± 2.14 for FBP and 9.02 ± 2.69 for IR. Mean CNR was 5.92 ± 1.80 for FBP and 6.95 ± 2.29 for IR. Mean effective radiation dose was 0.3 ± 0.1 mSv. Conclusion At a radiation dose of 0.3 ± 0.1 mSv, high-pitch dual-source CT yields LA images of consistently high quality using both FBP and IR. IR raises SNR and CNR without significantly improving subjective image quality.

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CBCT IN CONSERVATIVE DENTISTRY AND ENDODONTICS - A REVIEW

CODS Journal of Dentistry ◽

10.5005/cods-5-2-52 ◽

2013 ◽

Vol 5 (2) ◽

pp. 52-55

Author(s):

Prakash Lokhande ◽

G.B SHIVAMURTHY ◽

SAURAV KR SRIVASTAVA

Keyword(s):

Computed Tomography ◽

Radiation Dose ◽

Three Dimensional ◽

Conventional Radiography ◽

Cone Beam ◽

Effective Radiation Dose ◽

Conservative Dentistry ◽

Effective Radiation ◽

Endodontic Disease ◽

Review Current

ABSTRACT Cone beam computed tomography (CBCT) has been specifically designed to produce undistorted three-dimensional information of the maxillofacial skeleton, including the teeth and their surrounding tissues with a significantly lower effective radiation dose compared with conventional computed tomography (CT). The system overcomes many of the limitations of conventional radiography by producing undistorted, three-dimensional images of the area under examination. These properties make this form of imaging particularly suitable for use in endodontics. The clinician can obtain an enhanced appreciation of the anatomy being assessed, leading to an improvement in the detection of endodontic disease and resulting in more effective treatment planning. In addition, CBCT operates with a significantly lower effective radiation dose when compared with conventional computed tomography (CT). The aim of this paper is to review current literature on the applications and limitations of CBCT in the management of endodontic problems.

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Estimating radiation exposure during paediatric cardiac catheterisation: a potential for radiation reduction with air gap technique

Cardiology in the Young ◽

10.1017/s1047951119002506 ◽

2019 ◽

Vol 29 (12) ◽

pp. 1474-1480

Author(s):

Reid C. Chamberlain ◽

Alexis C. Shindhelm ◽

Chu Wang ◽

Gregory A. Fleming ◽

Kevin D. Hill

Keyword(s):

Image Quality ◽

Radiation Dose ◽

Air Gap ◽

Effective Radiation Dose ◽

Lateral Projection ◽

Gap Technique ◽

Dose Optimisation ◽

Patient Size ◽

Quality Assessments ◽

Effective Radiation

AbstractIntroduction:The air gap technique (AGT) is an approach to radiation dose optimisation during fluoroscopy where an “air gap” is used in place of an anti-scatter grid to reduce scatter irradiation. The AGT is effective in adults but remains largely untested in children. Effects are expected to vary depending on patient size and the amount of scatter irradiation produced.Methods:Fluoroscopy and cineangiography were performed using a Phillips Allura Fluoroscope on tissue simulation anthropomorphic phantoms representing a neonate, 5-year-old, and teenager. Monte Carlo simulations were then used to estimate effective radiation dose first using a standard recommended imaging approach and then repeated using the AGT. Objective image quality assessments were performed using an image quality phantom.Results:Effective radiation doses for the neonate and 5-year-old phantom increased consistently (2–92%) when the AGT was used compared to the standard recommended imaging approaches in which the anti-scatter grid is removed at baseline. In the teenage phantom, the AGT reduced effective doses by 5–59%, with greater dose reductions for imaging across the greater thoracic dimension of lateral projection. The AGT increased geometric magnification but with no detectable change in image blur or contrast differentiation.Conclusions:The AGT is an effective approach for dose reduction in larger patients, particularly for lateral imaging. Compared to the current dose optimisation guidelines, the technique may be harmful in smaller children where scatter irradiation is minimal.

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Ultra-low-dose computed tomography and its utility in wrist trauma in the emergency department

Acta Radiologica ◽

10.1177/0284185121989958 ◽

2021 ◽

pp. 028418512198995

Author(s):

Erdal Tekin ◽

Kutsi Tuncer ◽

Ibrahim Ozlu ◽

Recep Sade ◽

Rustem Berhan Pirimoglu ◽

...

Keyword(s):

Computed Tomography ◽

Image Quality ◽

Radiation Dose ◽

Low Dose ◽

Standard Dose ◽

Control Group ◽

Study Group ◽

Effective Radiation Dose ◽

Wrist Trauma ◽

Effective Radiation

Background The use and frequency of computed tomography (CT) are increasing day by day in emergency departments (ED). This increases the amount of radiation exposed. Purpose To evaluate the image quality obtained by ultra-low-dose CT (ULDCT) in patients with suspected wrist fractures in the ED and to investigate whether it is an alternative to standard-dose CT (SDCT). Material and Methods This is a study prospectively examining 336 patients who consulted the ED for wrist trauma. After exclusion criteria were applied, the patients were divided into the study and control groups. Then, SDCT (120 kVp and 100 mAs) and ULDCT (80 kVp and 5 mAs) wrist protocols were applied simultaneously. The images obtained were evaluated for image quality and fracture independently by a radiologist and an emergency medical specialist using a 5-point scale. Results The effective radiation dose calculated for the control group scans was 41.1 ± 2.1 µSv, whereas the effective radiation dose calculated for the study group scans was 0.5 ± 0.0 µSv. The effective radiation dose of the study group was significantly lower than that of the control group ( P < 0.01). The CT images in the study group showed no significant differences in the mean image quality score between observer 1 and observer 2 (3.4 and 4.3, respectively; P = 0.58). Both observers could detect all fractures using the ULDCT images. Conclusion ULDCT provides high-quality images in wrist traumas while reducing the radiation dose by approximately 98% compared to SDCT without any changes in diagnostic accuracy.

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Comparison of Dual- and Single-Source Dual-Energy CT for Diagnosis of Acute Pulmonary Artery Embolism

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren ◽

10.1055/a-1245-0035 ◽

2020 ◽

Author(s):

Bernhard Petritsch ◽

Pauline Pannenbecker ◽

Andreas Max Weng ◽

Simon Veldhoen ◽

Jan-Peter Grunz ◽

...

Keyword(s):

Pulmonary Embolism ◽

Image Quality ◽

Radiation Dose ◽

Dual Energy ◽

Dual Energy Ct ◽

Suspected Pulmonary Embolism ◽

Effective Radiation Dose ◽

Distribution Maps ◽

Filter Group ◽

Effective Radiation

Purpose Comparison of dual-source dual-energy CT (DS-DECT) and split-filter dual-energy CT (SF-DECT) regarding image quality and radiation dose in patients with suspected pulmonary embolism. Materials and Methods We retrospectively analyzed pulmonary dual-energy CT angiography (CTPA) scans performed on two different CT scanners in 135 patients with suspected pulmonary embolism (PE). Scan parameters for DS-DECT were 90/Sn150 kV (n = 68 patients), and Au/Sn120 kV for SF-DECT (n = 67 patients). The iodine delivery rate was 1400 mg/s in the DS-DECT group vs. 1750 mg/s in the SF-DECT group. Color-coded iodine distribution maps were generated for both protocols. Objective (CT attenuation of pulmonary trunk [HU], signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR]) and subjective image quality parameters (two readers [R], five-point Likert scale), as well as radiation dose parameters (effective radiation dose, size-specific dose estimations [SSDE]) were compared. Results All CTPA scans in both groups were of diagnostic image quality. Subjective CTPA image quality was rated as good or excellent in 80.9 %/82.4 % (R1 / R2) of DS-DECT scans, and in 77.6 %/76.1 % of SF-DECT scans. For both readers, the image quality of split-filter iodine distribution maps was significantly lower (p < 0.05) with good or excellent ratings in only 43.3 %/46.3 % (R1 / R2) vs. 83.8 %/88.2 % for maps from DS-DECT. The HU values of the pulmonary trunk did not differ between the two techniques (p = n. s.), while both the SNR and CNR were significantly higher in the split-filter group (p < 0.001; p = 0.003). Both effective radiation dose (2.70 ± 1.32 mSv vs. 2.89 ± 0.94 mSv) and SSDE (4.71 ± 1.63 mGy vs. 5.84 ± 1.11 mGy) were significantly higher in the split-filter group (p < 0.05). Conclusion The split-filter allows for dual-energy imaging of suspected pulmonary embolism but is associated with lower iodine distribution map quality and higher radiation dose. Key points: Citation Format

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Effect of Different Iterative Reconstruction Algorithms on Ultra-Low Dose CT of Inflammatory Bowel Disease in a Rabbit Model

Korean Journal of Abdominal Radiology ◽

10.52668/kjar.2021.00059 ◽

2021 ◽

Vol 5 (1) ◽

pp. 32-41

Author(s):

Cheong-Il Shin ◽

Se Hyung Kim ◽

Mi Hye Yu ◽

Ijin Joo ◽

Joon Koo Han

Keyword(s):

Inflammatory Bowel Disease ◽

Image Quality ◽

Radiation Dose ◽

Bowel Disease ◽

Diagnostic Performance ◽

Low Dose ◽

Rabbit Model ◽

Effective Radiation Dose ◽

Inflammatory Bowel ◽

Effective Radiation

Purpose: To evaluate the feasibility of ultra-low dose 80 kVp CT for the evaluation of inflammatory bowel disease (IBD) in a rabbit model and to investigate the effect of two different iterative reconstruction (IR) algorithms on 80 kVp CT in terms of image quality and diagnostic performance in comparison with same session conventional 120 kVp images.Materials and Methods: This study was approved by the Animal Care and Use Committee of our hospital. Twenty-eight New Zealand white rabbits were randomly divided into two groups: IBD group (n=18) and a control group (n=10). To create an acute IBD model, 3mL of a 5% w/v tri-nitrobenzene sulfonic acid solution was administered to the sigmoid colon of the rabbits. CT was performed at 80 kVp and 120 kVp and was reconstructed using filtered back projection (FBP), hybrid statistic-based IR, and full IR algorithms for 80 kVp and using FBP only for 120 kVp. Effective radiation dose, image noise, image quality, and diagnostic performance by two reviewers were recorded and compared using repeated measure analysis of variance, McNemar test, and receiver operating curve (ROC) analysis.Results: Mean effective radiation dose of 80 kVp CT (0.05 mSv) was significantly lower than that (0.285 mSv) of 120 kVp CT. Mean image noise was highest in the 80 kVp FBP setting (60.36) but significantly decreased with IR algorithms (47.02 with hybrid IR and 12.92 with full IR) (P<0.0001). Mean overall image quality score was lowest in the 80 kVp FBP setting (1.57 and 1.46 for reviewers 1 and 2, respectively) but significantly improved with IR algorithms (2.43 and 2.25 for hybrid IR and 4.79 and 4.93 for full IR) (P<0.0001). Sensitivity and area under the curve (AUC) for differentiating a normal bowel from IBD was lowest with 80 kVp FBP (61.1% and 83.3%; 0.883 and 0.967) but improved with IR algorithms (83.3%~100%; 0.992~1), to similar levels as the 120 kVp FBP setting (100% and 1). Differences in sensitivity and AUC between 80 kVp FBP and 80 kVp IR algorithms were statistically significant in reviewer 1.Conclusions: Ultra-low dose 80 kVp CT in a rabbit IBD model is not feasible using the standard FBP algorithm. However, with the application of IR algorithms, diagnostic performance of 80 kVp CT was acceptable and on par with that at conventional 120 kVp FBP.

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Head and neck single- and dual-energy CT: differences in radiation dose and image quality of 2nd and 3rd generation dual-source CT

British Journal of Radiology ◽

10.1259/bjr.20210069 ◽

2021 ◽

pp. 20210069

Author(s):

Lukas Lenga ◽

Marvin Lange ◽

Simon S Martin ◽

Moritz H Albrecht ◽

Christian Booz ◽

...

Keyword(s):

Image Quality ◽

Radiation Dose ◽

Head And Neck ◽

Figure Of Merit ◽

Third Generation ◽

Effective Radiation Dose ◽

Dual Source ◽

Effective Radiation ◽

Group D

Objectives: To compare radiation dose and image quality of single-energy (SECT) and dual-energy (DECT) head and neck CT examinations performed with second- and third-generation dual-source CT (DSCT) in matched patient cohorts. Methods: 200 patients (mean age 55.1 ± 16.9 years) who underwent venous phase head and neck CT with a vendor-preset protocol were retrospectively divided into four equal groups (n = 50) matched by gender and BMI: second (Group A, SECT, 100-kV; Group B, DECT, 80/Sn140-kV), and third-generation DSCT (Group C, SECT, 100-kV; Group D, DECT, 90/Sn150-kV). Assessment of radiation dose was performed for an average scan length of 27 cm. Contrast-to-noise ratio measurements and dose-independent figure-of-merit calculations of the submandibular gland, thyroid, internal jugular vein, and common carotid artery were analyzed quantitatively. Qualitative image parameters were evaluated regarding overall image quality, artifacts and reader confidence using 5-point Likert scales. Results: Effective radiation dose (ED) was not significantly different between SECT and DECT acquisition for each scanner generation (p = 0.10). Significantly lower effective radiation dose (p < 0.01) values were observed for third-generation DSCT groups C (1.1 ± 0.2 mSv) and D (1.0 ± 0.3 mSv) compared to second-generation DSCT groups A (1.8 ± 0.1 mSv) and B (1.6 ± 0.2 mSv). Figure-of-merit/contrast-to-noise ratio analysis revealed superior results for third-generation DECT Group D compared to all other groups. Qualitative image parameters showed non-significant differences between all groups (p > 0.06). Conclusion: Contrast-enhanced head and neck DECT can be performed with second- and third-generation DSCT systems without radiation penalty or impaired image quality compared with SECT, while third-generation DSCT is the most dose efficient acquisition method. Advances in knowledge: Differences in radiation dose between SECT and DECT of the dose-vulnerable head and neck region using DSCT systems have not been evaluated so far. Therefore, this study directly compares radiation dose and image quality of standard SECT and DECT protocols of second- and third-generation DSCT platforms.

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