Substantial radiation dose reduction with consistent image quality using a novel low-dose stone composition protocol

Apfaltrer, Georg; Dutschke, Anja; Baltzer, Pascal; Schestak, Christian; Özsoy, Mehmet; Seitz, Christian; Veser, Julian; Petter, Elisabeth; Helbich, Thomas H.; Ringl, Helmut; Apfaltrer, Paul

doi:10.1007/s00345-020-03082-6

Cited by 12 publications

(9 citation statements)

References 30 publications

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“…Another factor might be the slightly higher WED in our LD group compared to SP patients. Regarding diagnostic image quality, there was no deterioration of image quality in LD acquisition in our study, which is similar to previous examinations with tin filtration [20,[24][25][26].…”

Section: Discussionsupporting

confidence: 91%

Low-Dose CT for Renal Calculi Detection Using Spectral Shaping of High Tube Voltage

Gassenmaier

Winkelmann

Magnus

et al. 2022

Rofo

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Purpose To investigate reduction of radiation exposure in unenhanced CT in suspicion of renal calculi using a tin-filtered high tube voltage protocol compared to a standard low-dose protocol without spectral shaping. Materials and Methods A phantom study using 7 human renal calculi was performed to test both protocols. 120 consecutive unenhanced CT examinations performed due to suspicion of renal calculi were included in this retrospective, monocentric study. 60 examinations were included with the standard-dose protocol (SP) (100 kV/130 mAs), whereas another 60 studies were included using a low-dose protocol (LD) applying spectral shaping with tin filtration of high tube voltages (Sn150 kV/80 mAs). Image quality was assessed by two radiologists in consensus blinded to technical parameters using an equidistant Likert scale ranging from 1–5 with 5 being the highest score. Quantitative image quality was assessed using regions of interest in abdominal organs, muscles, and adipose tissue to analyze image noise and signal-to-noise ratios (SNR). Commercially available dosimetry software was used to determine and compare effective dose (ED) and size-specific dose estimates (SSDEmean). Results All seven renal calculi of the phantom could be detected with both protocols. There was no difference regarding calcluli size between the two protocols except for the smallest one. The smallest concretion measured 1.5 mm in LD and 1.0 mm in SP (ground truth 1.5 mm). CTDIvol was 3.36 mGy in LD (DLP: 119.3 mGycm) and 8.27 mGy in SP (DLP: 293.6 mGycm). The mean patient age in SP was 47 ± 17 years and in LD 49 ± 13 years. Ureterolithiasis was found in 33 cases in SP and 32 cases in LD. The median concretion size was 3 mm in SP and 4 mm in LD. The median ED in LD was 1.3 mSv (interquartile range (IQR) 0.3 mSv) compared to 2.3 mSv (IQR 0.9 mSv) in SP (p < 0.001). The SSDEmean of LD was also significantly lower compared to SP with 2.4 mGy (IQR 0.4 mGy) vs. 4.8 mGy (IQR 2.3 mGy) (p < 0.001). The SNR was significantly lower in LD compared to SP (p < 0.001). However, there was no significant difference between SP and LD regarding the qualitative assessment of image quality with a median of 4 (IQR 1) for both groups (p = 0.648). Conclusion Tin-filtered unenhanced abdominal CT for the detection of renal calculi using high tube voltages leads to a significant reduction of radiation exposure and yields high diagnostic image quality without a significant difference compared to the institution’s standard of care low-dose protocol without tin filtration. Key Points: Citation Format

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Section: Discussionsupporting

confidence: 91%

Low-Dose CT for Renal Calculi Detection Using Spectral Shaping of High Tube Voltage

Gassenmaier

Winkelmann

Magnus

et al. 2022

Rofo

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“…Some limitations need to be mentioned. The evaluation of stones in terms of material compositions is best performed by means of dual-energy CT [ 35 ]. However, this technique is not always available in every center and often is associated with higher radiation exposure [ 24 , 35 , 36 ].…”

Section: Discussionmentioning

confidence: 99%

“…The evaluation of stones in terms of material compositions is best performed by means of dual-energy CT [ 35 ]. However, this technique is not always available in every center and often is associated with higher radiation exposure [ 24 , 35 , 36 ]. In our institute, the detection of reno-ureteric stones was performed with a single tube potential.…”

Section: Discussionmentioning

confidence: 99%

Influence of a Deep Learning Noise Reduction on the CT Values, Image Noise and Characterization of Kidney and Ureter Stones

et al. 2022

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Deep-learning (DL) noise reduction techniques in computed tomography (CT) are expected to reduce the image noise while maintaining the clinically relevant information in reduced dose acquisitions. This study aimed to assess the size, attenuation, and objective image quality of reno-ureteric stones denoised using DL-software in comparison to traditionally reconstructed low-dose abdominal CT-images and evaluated its clinical impact. In this institutional review-board-approved retrospective study, 45 patients with renal and/or ureteral stones were included. All patients had undergone abdominal CT between August 2019 and October 2019. CT-images were reconstructed using the following three methods: filtered back-projection, iterative reconstruction, and PixelShine (DL-software) with both sharp and soft kernels. Stone size, CT attenuation, and objective image quality (signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR)) were evaluated and compared using Bonferroni-corrected Friedman tests. Objective image quality was measured in six regions-of-interest. Stone size ranged between 4.4 × 3.1–4.4 × 3.2 mm (sharp kernel) and 5.1 × 3.8–5.6 × 4.2 mm (soft kernel). Mean attenuation ranged between 704–717 Hounsfield Units (HU) (soft kernel) and 915–1047 HU (sharp kernel). Differences in measured stone sizes were ≤1.3 mm. DL-processed images resulted in significantly higher CNR and SNR values (p < 0.001) by decreasing image noise significantly (p < 0.001). DL-software significantly improved objective image quality while maintaining both correct stone size and CT-attenuation values. Therefore, the clinical impact of stone assessment in denoised image data sets remains unchanged. Through the relevant noise suppression, the software additionally offers the potential to further reduce radiation exposure.

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“…Recently published studies based on modern dual-energy CT scanners with optimized scan protocols for the detection and evaluation of kidney and ureter stones report on effective doses of slightly over 3 mSv [ 10 , 14 , 29 , 30 , 31 ]. Although a direct comparison of these studies with the present study appears inappropriate, it nevertheless points to the great potential of PCD detectors to reduce the radiation dose for patients.…”

Section: Discussionmentioning

confidence: 99%

Clinical Low Dose Photon Counting CT for the Detection of Urolithiasis: Evaluation of Image Quality and Radiation Dose

et al. 2022

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The purpose of this study was the evaluation of image quality and radiation dose parameters of the novel photon counting CT (PCCT, Naeotom Alpha, Siemens Healthineers) using low-dose scan protocols for the detection of urolithiasis. Standard CT scans were used as a reference (S40, Somatom Sensation 40, Siemens Healthineers). Sixty-three patients, who underwent CT scans between August and December 2021, were retrospectively enrolled. Thirty-one patients were examined with the PCCT and 32 patients were examined with the S40. Radiation dose parameters, as well as quantitative and qualitative image parameters, were analyzed. The presence of urolithiasis, image quality, and diagnostic certainty were rated on a 5-point-scale by 3 blinded readers. Both patient groups (PCCT and S40) did not differ significantly in terms of body mass index. Radiation dose was significantly lower for examinations with the PCCT compared to the S40 (2.4 ± 1.0 mSv vs. 3.4 ± 1.0 mSv; p < 0.001). The SNR was significantly better on images acquired with the PCCT (13.3 ± 3.3 vs. 8.2 ± 1.9; p < 0.001). The image quality of the PCCT was rated significantly better (4.3 ± 0.7 vs. 2.8 ± 0.6; p < 0.001). The detection rate of kidney or ureter calculi was excellent with both CT scanners (PCCT 97.8% and S40 99%, p = 0.611). In high contrast imaging, such as the depiction of stones of the kidney and the ureter, PCCT allows a significant reduction of radiation dose, while maintaining excellent diagnostic confidence and image quality. Given this image quality with our current protocol, further adjustments towards ultra-low-dose CT scans appear feasible.

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Substantial radiation dose reduction with consistent image quality using a novel low-dose stone composition protocol

Cited by 12 publications

References 30 publications

Low-Dose CT for Renal Calculi Detection Using Spectral Shaping of High Tube Voltage

Low-Dose CT for Renal Calculi Detection Using Spectral Shaping of High Tube Voltage

Influence of a Deep Learning Noise Reduction on the CT Values, Image Noise and Characterization of Kidney and Ureter Stones

Clinical Low Dose Photon Counting CT for the Detection of Urolithiasis: Evaluation of Image Quality and Radiation Dose

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