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 - Publication

Publication

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

Journal Paper/Review - Mar 22, 2016

Dewes Patricia, Frellesen Claudia, Scholtz Jan-Erik, Fischer Sebastian, Vogl Thomas J, Bauer Ralf, Schulz Boris

Citation

Dewes P, Frellesen C, Scholtz J, Fischer S, Vogl T, Bauer R, Schulz B. 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. Eur J Radiol 2016; 85:1058-62.

Type

Journal Paper/Review (English)

Journal

Eur J Radiol 2016; 85

Publication Date

Mar 22, 2016

Issn Electronic

1872-7727

Pages

1058-62

Brief description/objective

OBJECTIVES
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 150kV (150kV Sn) on a third-generation dual-source-CT, 33 patients were examined with automated kV-selection (110-140kV) 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 (100-140kV). 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=0.86-0.91) 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 150kV 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 150kV source spectrum by a tin filter substantially lowers patient exposure while improving image quality on un-enhanced abdominal computed tomography for urinary stone disease.