Ultrasound of the spleen – an update on measurements, reference values, and influencing factors. A systematic review.

Reliable and reproducible measurement methods have been established, and reference values are used in almost all scientific disciplines. The knowledge of reference values is crucial to distinguish physiological from pathological processes and, therefore, subsequently, for the clinical management of patients. The image storage and documentation of measurements and normal findings should be part of quality assurance in imaging. This paper aims to review published literature and provide current knowledge of sonographic measurements of the spleen, examination techniques, and knowledge of normal values with their possible clinical implications. Moreover, the role of clinical influencing factors such as age, gender, or ethnicity is also analyzed.