[Effect of Different Look Up Tables on Contrast Effect in Lower Limb Angiography Using the Frequency Subtraction Method].

Abstract

Purpose: The purpose of this study was to investigate the impact of different look up tables (LUTs) on contrast enhancement in lower extremity angiography using the frequency subtraction method.

Methods: A lower extremity vascular phantom was constructed, and contrast medium concentrations of 100%, 75%, 50%, and 25% were prepared. Imaging was performed using the frequency subtraction method, and each image was processed with different LUTs (linear, A, and C). The linear LUT at 100% concentration (linear-100%) served as the control. Contrast was quantified using profile curves, and subjective image quality was assessed by the degradation category rating method.

Results: In the central region of the bone, LUT A-100% and C-100% yielded higher contrast values compared with the control. At the bone margins, A-100%, A-75%, and A-50% demonstrated greater contrast enhancement. Subjective evaluation showed that scores for A-50% and C-50% in the central bone region exceeded the tolerance limit. In the cortical bone region, scores for A-75% and C-50% exceeded the acceptable limit.

Conclusion: It was demonstrated that appropriate modification of LUTs in the frequency subtraction method contributes to improved contrast enhancement.