Metal Artifact Reduction for Orthopedic Prosthesis in Lower Extremity CT Venography: Evaluation of Image Quality and Vessel Conspicuity.

PURPOSE

This study evaluates the image quality of lower extremity CT venography reconstructed with orthopedic metal artifact reduction (O-MAR) in patients with unilateral or bilateral metallic prostheses in the hip or knee.

METHODS

This retrospective study was approved by our institutional review board, and informed consent was waived. Twenty-nine patients of lower extremity CT with 51 metallic hip or knee prostheses were reconstructed to both standard CT images and O-MAR images. The subjective image quality and vessel conspicuity for both images were evaluated by two readers using five-point scales (0-4). Vessel conspicuity scores of 3 or 4 were considered diagnostically acceptable. Image noise was measured in the air and subcutaneous fat.

RESULTS

O-MAR images showed significantly higher scores of subjective image quality (p < .001) and vessel conspicuity (p = .002) than standard CT images. Diagnostic acceptance of vessel conspicuity was not significantly different between O-MAR images and standard CT images (p = 1.000). O-MAR images showed significantly less image noise than conventional CT images (p < .001 for both air and subcutaneous fat).

CONCLUSION

O-MAR may be an effective solution for the metal artifacts in lower extremity CT venography; however, the distance between prostheses and vessels affects the diagnostic acceptance in patients with metallic hip or knee prostheses.

LEVEL OF EVIDENCE

Level 4, Case Series.