Artifacts in cardiac T1 and T2 mapping techniques - Influence on reliable quantification.

Cardiac T1 and T2 mapping techniques are well-established methods for obtaining quantitative pixelwise representations of myocardial tissue properties. Mapping images are commonly evaluated quantitatively, and their resulting values play a crucial role in diagnosis and therapeutic decision making in various cardiac pathologies. Despite the validated effectiveness of these techniques, both methodological and patient-specific confounders must be considered when applying them in clinical and research settings. Artifacts - erroneous features within the MR image - can be misinterpreted as true anatomical structures or pathologies, potentially confounding quantitative analyses, conducted by both human readers and AI algorithms. Artifacts can arise from sources such as patient motion, metal objects, hardware constraints, patient-specific scanner adjustments (e.g. flip-angle calibration) and processing errors, particularly within the complex environment of cardiac imaging. While artifact sources in other CMR sequences are well documented, cardiac parametric mapping presents unique challenges due to its distinct image generation and quantitative assessment. This article provides an overview of artifacts encountered in cardiac T1 and T2 mapping, along with a concise explanation of their origins, aiming to raise awareness of their potential impact on clinical decision making. Future developments, including sequences designed to mitigate mapping artifacts, are also briefly discussed. A strong interaction between scientists and clinicians is needed to overcome these challenges and maintain the reliability of quantification results.