Uniformity test in three-dimensional rotational angiography: Novel tools and methods for advanced performance evaluation

Introduction: American Association of Physicists in Medicine (AAPM) Task Group (TG) 238 provides guidance on quality control procedures to ensuring optimal three-dimensional rotational angiography (3DRA) image quality. The uniformity test outlined in this guideline utilizes a sampling method, which provide limited information on image uniformity and has been found to be a sub-optimum predictor of image quality issues. Despite this limitation, numerous automated quality control software solutions for uniformity testing have been developed using the available method. Therefore, this study was aimed to propose new methods as well as to develop an in-house software to generate more comprehensive uniformity testing of 3DRA images. Methods: The uniformity evaluation techniques are adopted from both AAPM TG-238 guidelines and the European Reference Organisation for Quality Assured Breast Screening and Diagnostic Services (EUREF) guidelines. The parameters assessed included mean pixel value (MPV) and signal to noise ratio (SNR) following EUREF recommendations with limiting values adapted from AAPM TG-238. An in-house software was constructed to visually display non-uniformities and numerically by providing information on ROIs detected by each metric. Results: With the introduction of new evaluation methods, the previously established limiting values could not be employed as a reference for determining image uniformity. Therefore, the selection of the optimal uniformity testing method will be based on its sensitivity in detecting and visually displaying non-uniformities. Conclusion: The new evaluation techniques provide a more comprehensive assessment of 3DRA image uniformity. However, further investigation is reserved to refine the limitation values used in determining the pass/fail criteria for the uniformity test. Implications for practice: This in-house software enables visualization of uniformity within an image, aiding in the selection of the appropriate imaging mode based on clinical requirements.