Fine focal spot size improves image quality in computed tomography abdomen and pelvis.

OBJECTIVES

To compare the image quality between fine focal spot size (FFSS) and standard focal spot size (SFSS) in computed tomography of the abdomen and pelvis (CTAP) METHODS: This retrospective review included all consecutive adult patients undergoing contrast-enhanced CTAP between June and September 2014. Two blinded radiologists assessed the margin clarity of the abdominal viscera and the detected lesions using a five-point grading scale. Cohen's kappa test was used to examine the inter-observer reliability between the two reviewers for organ margin clarity. Mann-Whitney U testing was utilised to assess the statistical difference of the organ and lesion margin clarity.

RESULTS

100 consecutive CTAPs were recruited. 52 CTAPs were examined with SFSS of 1.1 × 1.2 mm and 48 CTAPs were examined with FFSS of 0.6 × 0.7 mm. Results showed that there was substantial agreement for organ margin clarity (mean κ = 0.759, p < 0.001) among the reviewers. FFSS produces images with clearer organ margins (U = 76194.0, p < 0.001, r = 0.523) and clearer lesion margins (U = 239, p = 0.052, r = 0.269).

CONCLUSION

FFSS CTAP improves image quality in terms of better organ and lesion margin clarity. Fine focus CT scanning is a novel technique that may be applied in routine CTAP imaging.

KEY POINTS

• Fine focal spot improves organ margin clarity. • Fine focal spot improves lesion margin clarity. • Fine focal spot can be used in routine CT abdominal imaging.