Low-dose abdominal computed tomography for detection of urinary stone disease − Impact of additional spectral shaping of the X-ray beam on image quality and dose parameters

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• 作者：Patricia Dewes ; Claudia Frellesen ; Jan-Erik Scholtz ; Sebastian Fischer ; Thomas J. Vogl ; Ralf W. Bauer ; ^{ralfwbauer@aol.com" class="auth_mail" title="E-mail the corresponding author} ; Boris Schulz
• 关键词：ADMIRE ; advanced modeled iterative reconstruction ; ALARA ; as low as reasonably achievable ; BMI ; body mass index ; CT ; computed tomography ; CTDIvol ; CT dose index ; DLP ; dose-length-product ; DSCT ; dual-source CT ; FBP ; filtered back projection ; GFR ; glomerular filtration rate ; HU ; hounsfield units ; ICC ; intraclass correlation coefficient ; Sn ; tin filter ; SNR ; signal-to-noise ratio
• 刊名：European Journal of Radiology
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：85
• 期：6
• 页码：1058-1062
• 全文大小：1750 K

文摘

To evaluate a novel tin filter-based abdominal CT protocol for urolithiasis in terms of image quality and CT dose parameters.

Methods

130 consecutive patients with suspected urolithiasis underwent non-enhanced CT with three different protocols: 48 patients (group 1) were examined at tin-filtered 150 kV (150 kV Sn) on a third-generation dual-source-CT, 33 patients were examined with automated kV-selection (110–140 kV) based on the scout view on the same CT-device (group 2), and 49 patients were examined on a second-generation dual-source-CT (group 3) with automated kV-selection (100–140 kV). Automated exposure control was active in all groups. Image quality was subjectively evaluated on a 5-point-likert-scale by two radiologists and interobserver agreement as well as signal-to-noise-ratio (SNR) was calculated. Dose-length-product (DLP) and volume CT dose index (CTDIvol) were compared.

Results

Image quality was rated in favour for the tin filter protocol with excellent interobserver agreement (ICC = 0.86&ndash;0.91) and the difference reached statistical significance (p < 0.001). SNR was significantly higher in group 1 and 2 compared to second-generation DSCT (p < 0.001). On third-generation dual-source CT, there was no significant difference in SNR between the 150 kV Sn and the automated kV selection protocol (p = 0.5). The DLP of group 1 was 23% and 21% (p < 0.002) lower in comparison to group 2 and 3, respectively. So was the CTDIvol of group 1 compared to group 2 (−36%) and 3 (−32%) (p < 0.001).

Conclusion

Additional shaping of a 150 kV source spectrum by a tin filter substantially lowers patient exposure while improving image quality on un-enhanced abdominal computed tomography for urinary stone disease.