Imaging of the nail unit in psoriatic patients:A systematic scoping review of techniques and terminology

BACKGROUND: The growing interest in the visualization of psoriatic nail unit changes has led to the discovery of an abundance of image characteristics across various modalities. OBJECTIVE: To identify techniques for non‐invasive imaging of nail unit structures in psoriatic patients and review extracted image features to unify the diverse terminology. METHODS: For this systematic scoping review, we included studies available on PubMed and Embase, independently extracted image characteristics, and semantically grouped the identified features to suggest a preferred terminology for each technique. RESULTS: After screening 753 studies, 67 articles on the visualization of clinical and subclinical psoriatic changes in the nail plate, matrix, bed, folds and hyponychium were included. We identified 4 optical and 3 radiological imaging techniques for the assessment of surface (dermoscopy [n = 16], capillaroscopy [n = 12]), sub‐surface (ultrasound imaging [n = 36], optical coherence tomography [n = 4], fluorescence optical imaging [n = 3]), and deep‐seated psoriatic changes (magnetic resonance imaging [n = 2], positron emission tomography‐computed tomography [n = 1]). By condensing 244 image feature descriptions into a glossary of 82 terms, overall redundancy was cut by 66.4% (37.5%–77.1%). More than 75% of these image features provide additional disease‐relevant information that is not captured using conventional clinical assessment scales. CONCLUSIONS: This review has identified, unified, and contextualized image features and related terminology for non‐invasive imaging of the nail unit in patients with psoriatic conditions. The suggested glossary could facilitate the integrative use of non‐invasive imaging techniques for the detailed examination of psoriatic nail unit structures in research and clinical practice.