Role of metal artifact reduction software in computed tomography angiography of lower limb metallic prosthesis: A
Ahmad M Mounir1, Ali H Elmokadem2, Gehad A H Saleh2
1Department of Radiology, Mansoura University, Mansoura 35516, Egypt. ahmedmounir@mans.edu.eg.
Background:
Metal artifacts significantly limit the diagnostic quality of computed tomography (CT) algorithm in patients with lower limb metallic prostheses. Single-energy metal artifact reduction (SEMAR) algorithms have been developed to address this limitation.
Aim:
To evaluate the effects of SEMAR algorithm on image quality characteristics of lower limb CT algorithm (CTA) (artifact reduction, signal-to-noise ratio [SNR] and inter-observer agreement) in patients with metallic prostheses.
Methods:
Twenty-two patients (14 males, 8 females; median age 54 years) with unilateral or bilateral metal lower limb prostheses or screws underwent lower limb CTA on a 128-slice multi-detector CT scanner. Images were reconstructed with and without SEMAR algorithm. Three radiologists independently assessed subjective image quality using standardized scoring systems. Quantitative analysis included measurement of SNR and contrast-to-noise ratio in arterial and soft tissue regions of interest.
Results:
Application of SEMAR significantly improved SNR in two of three observers (P = 0.009 and P = 0.004), with values approaching those in the contralateral reference limb. Overall artifact reduction was statistically significant (median difference 1.5 Hounsfield unit, P < 0.001), as was improvement in overall image quality (median difference 1 Hounsfield unit, P < 0.001). Good inter-observer agreement (intraclass correlation coefficient > 0.75) was demonstrated for SNR and contrast-to-noise ratio assessment with metal artifact reduction (MAR) and reference images, while poor agreement (intraclass correlation coefficient < 0.5) was noted for non-MAR images. Kendall's W demonstrated significant concordance among observers (W = 0.899, P < 0.001 for study quality with MAR).
Conclusion:
SEMAR algorithm significantly reduces metal artifacts from lower limb fixation prostheses without compromising vessel contrast, improving visualization of periprosthetic vascular structures and enhancing diagnostic capability of CTA examinations.
