CT for evaluation of potential renal donors - how does iterative reconstruction influence image quality and dose?

PURPOSE

To assess ASIR (adaptive statistical iterative reconstruction) technique regarding dose reduction and its impact on image quality in evaluation CTs of potential kidney donors.

MATERIALS AND METHODS

Between May and November 2013, a prospective study of 53 assumingly healthy potential kidney donors was conducted. The subjects underwent abdominal evaluation CT prior to the planned explantation of a kidney and were randomly divided into 2 groups: Group A was examined with an ASIR 40 protocol (n=26), group B (n=27) was examined using a standard FBP (filtered back projection) protocol. Image quality was assessed both quantitatively (by obtaining attenuation values in different organ regions and calculating SNR and CNRs) and qualitatively (by two observers who evaluated image quality using a 5-point scale system). Applied dose was analyzed as CTDIvol (mGy), total DLP (mGy×cm) and effective dose (mSv).

RESULTS

Applied dose in group A was about 26% lower than in group B (p<0.05). Between both groups, dose determining parameters such as scan length and patients' body diameter showed no significant difference. SNR (signal-to-noise ratio) was significantly higher in group A (p<0.05). CNRs (contrast-to-noise ratios) for different tissues were not significantly different. Observer rated image quality showed no significant difference.

CONCLUSION

ASIR can contribute to a relevant dose reduction without any loss of image quality in CT scans for evaluating potential kidney donors.