Evaluation of an adaptive detector collimation for prospectively ECG-triggered coronary CT angiography with third-generation dual-source CT

Messerli, Michael; Dewes, Patricia; Scholtz, Jan-Erik; Arendt, Christophe; Wildermuth, Simon; Vogl, Thomas J.; Bauer, Ralf W.

doi:10.1007/s00330-017-5177-1

Cited by 12 publications

(12 citation statements)

References 29 publications

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“…This potential for dose reduction is greatest for the hip region, and thus scan length should only include the greater trochanter and femoral head. Use of an adaptive collimation may additionally decrease radiation dose [ 30 , 31 ].…”

Section: Discussionmentioning

confidence: 99%

Diagnostic accuracy of ultra-low-dose CT for torsion measurement of the lower limb

et al. 2020

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Objectives The study aimed to investigate the diagnostic performance of simulated ultra-low-dose CT (ULD-CT) for torsion measurement of the lower limb. Methods Thirty retrospectively identified patients were included (32.3 ± 14.2 years; 14 women, 16 men). ULD-CT simulations were generated at dose levels of 100%, 10%, 5%, and 1% using two reconstruction methods: standard filtered back projection (FBP) and iterative reconstruction (ADMIRE). Two readers measured the lower limb torsion in all data sets. The readers also captured image noise in standardized anatomical landmarks. All data sets were evaluated regarding subjective diagnostic confidence (DC; 5-point Likert scale). Effective radiation dose of the original data sets and the simulated ULD-CT was compared. Results There was no significant difference of measured lower limb torsion in any simulated dose level compared to the original data sets in both readers. Dose length product (DLP) of the original examinations was 402.1 ± 4.3 mGy cm, which resulted in an effective radiation dose of 4.00 ± 2.12 mSv. Calculated effective radiation dose in ULD-CT at 1% of the original dose was 0.04 mSv. Image noise increased significantly with dose reduction (p < 0.0001) and was dependent on the reconstructional method (p < 0.0001) with less noise using ADMIRE compared to FBP. Both readers rated DC at doses 100%, 10%, and 5% with 5.0/5: there were no ratings worse than 3/5 at 1% dose level. Conclusions The results suggest that radiation dose reduction down to 1% of original CT dose levels may be achieved in CT torsion measurements of the lower limb without compromising diagnostic accuracy. Key Points • Modern CT delivers exceptional high image quality in musculoskeletal imaging, especially for evaluation of osseous structures. • Usually, this high image quality is accompanied by significant radiation exposure to the patient and may not always be required for the intended purpose, e.g., pure delineation of cortical bone of the lower limb. • This study shows the tremendous prospects of radiation dose reduction without compromising diagnostic confidence in CT torsion measurement of the lower limb.

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Section: Discussionmentioning

confidence: 99%

Diagnostic accuracy of ultra-low-dose CT for torsion measurement of the lower limb

et al. 2020

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“…Besides dose reduction, it also indicates that there is no significant difference in image quality. According to the previous study reports, apart from growing pitch factor and reducing tube current and tube voltage in the optimization phase, increasing slice collimation is a technique to minimize radiation dose without sacrificing image quality performance [41,42]. Furthermore, previous research indicates that increased beam collimation resulted in a decrease of around 17% over-ranging in CT study, which may prevent overexposure to patients and decreased dose to radiosensitive organs beyond primary beam [43].…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Organ Dose and Image Quality Metrics of Pediatric CT Chest-Abdomen-Pelvis (CAP) Examination: An Anthropomorphic Phantom Study

et al. 2021

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The aim of this study is to investigate the impact of CT acquisition parameter setting on organ dose and its influence on image quality metrics in pediatric phantom during CT examination. The study was performed on 64-slice multidetector CT scanner (MDCT) Siemens Definition AS (Siemens Sector Healthcare, Forchheim, Germany) using various CT CAP protocols (P1–P9). Tube potential for P1, P2, and P3 protocols were fixed at 100 kVp while P4, P5, and P6 were fixed at 80 kVp with used of various reference noise values. P7, P8, and P9 were the modification of P1 with changes on slice collimation, pitch factor, and tube current modulation (TCM), respectively. TLD-100 chips were inserted into the phantom slab number 7, 9, 10, 12, 13, and 14 to represent thyroid, lung, liver, stomach, gonads, and skin, respectively. The image quality metrics, signal to noise ratio (SNR) and contrast to noise ratio (CNR) values were obtained from the CT console. As a result, this study indicates a potential reduction in the absorbed dose up to 20% to 50% along with reducing tube voltage, tube current, and increasing the slice collimation. There is no significant difference (p > 0.05) observed between the protocols and image metrics.

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“…With both scanners used in this study, the scan duration is shorter, reducing the amount of CM required. The Flash CT scanner is a 64-slice scanner with two X-ray tubes, while the Force CT scanner has an additional wider-coverage detector (5.76 cm, 96-slice) 29,30 . Hence, in this study, we designed a new BSA protocol for Chinese adults in which the maximum contrast volume was reduced to 90 mL, corresponding to a maximum injection rate of 5 mL/s to keep the injection duration similar (approximately 13 s) for a BSA of 1.7-2.14 m 2 , with a reduction of 20 mL of contrast volume for large BSAs (> 2.15 m 2 ).…”

Section: Discussionmentioning

confidence: 99%

“…Gordic et al proved that the diagnostic rate in cases with a heart rate > 75 bpm on Force CT was only 14%. In fact, using a high-pitch mode on Flash CT requires that the heart rate www.nature.com/scientificreports/ did not exceed 63 bpm; this requirement was relaxed to 70 bpm on Force CT 29 .…”

Section: Discussionmentioning

confidence: 99%

“…Gordic et al proved that the diagnostic rate in cases with a heart rate > 75 bpm on Force CT was only 14%. In fact, using a high-pitch mode on Flash CT requires that the heart rate did not exceed 63 bpm; this requirement was relaxed to 70 bpm on Force CT 29 . Step-and-shoot acquisition has advantages over high-pitch scanning, due to the more relaxed heart rate limits 9 , 16 , 22 .…”

Section: Discussionmentioning

confidence: 99%

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Contrast medium administration with a body surface area protocol in step-and-shoot coronary computed tomography angiography with dual-source scanners

Jin

Gao

Sun

et al. 2020

Sci Rep

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We evaluated the feasibility and image quality of prospective electrocardiography (ECG)-triggered coronary computed tomography angiography (CCTA) using a body surface area (BSA) protocol for contrast-medium (CM) administration on both second- and third-generation scanners (Flash and Force CT), without using heart rate control. One-hundred-and-eighty patients with suspected coronary heart disease undergoing CCTA were divided into groups A (BSA protocol for CM on Flash CT), B (body mass index (BMI)-matched patients; BMI protocol for CM on Flash CT), and C (BMI-matched patients; BSA protocol for CM on Force CT). Patient characteristics, quantitative and qualitative measures, and radiation dose were compared between groups A and B, and A and C. Of the 180 patients, 99 were male (median age, 62 years). Average BSA in groups A, B, and C was 1.80 ± 0.17 m2, 1.74 ± 0.16 m2, and 1.64 ± 0.17 m2, respectively, with groups A and C differing significantly (P < 0.001). Contrast volume (50.50 ± 8.57 mL vs. 45.00 ± 6.18 mL) and injection rate (3.90 ± 0.44 mL/s vs. 3.63 ± 0.22 mL/s) differed significantly between groups A and C (P < 0.001). Groups A and C (both: all CT values > 250 HU, average scores > 4) achieved slightly lower diagnostic image quality than group B. The BSA protocol for CM administration was feasible in both Flash and Force CT, and therefore may be valuable in clinical practice.

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Evaluation of an adaptive detector collimation for prospectively ECG-triggered coronary CT angiography with third-generation dual-source CT

Abstract: • Adaptive detector collimation allows keeping patient exposure low in cardiac CT. • With novel detectors the desired scan length can be accurately matched. • Differences in detector settings may cause 62.7% of excessive dose.

Cited by 12 publications

References 29 publications

Diagnostic accuracy of ultra-low-dose CT for torsion measurement of the lower limb

Diagnostic accuracy of ultra-low-dose CT for torsion measurement of the lower limb

Evaluation of Organ Dose and Image Quality Metrics of Pediatric CT Chest-Abdomen-Pelvis (CAP) Examination: An Anthropomorphic Phantom Study

Contrast medium administration with a body surface area protocol in step-and-shoot coronary computed tomography angiography with dual-source scanners

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