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

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.