text: Lung Ultrasound in COVID 19 and Post COVID 19 Patients an Evidence Based Approach Worldwide lung ultrasound LUS was utilized to assess coronavirus disease 2019 COVID 19 patients Often imaging protocols were however defined arbitrarily and not following an evidence based approach Moreover extensive studies on LUS in post COVID 19 patients are currently lacking This study analyses the impact of different LUS imaging protocols on the evaluation of COVID 19 and post COVID 19 LUS data LUS data from 220 patients were collected 100 COVID 19 positive and 120 post COVID 19 A validated and standardized imaging protocol based on 14 scanning areas and a 4 level scoring system was implemented We utilized this dataset to compare the capability of 5 imaging protocols respectively based on 4 8 10 12 and 14 scanning areas to intercept the most important LUS findings This to evaluate the optimal trade off between a time efficient imaging protocol and an accurate LUS examination We also performed a longitudinal study aimed at investigating how to eventually simplify the protocol during follow up Additionally we present results on the agreement between AI models and LUS experts with respect to LUS data evaluation A 12 areas protocol emerges as the optimal trade off for both COVID 19 and post COVID 19 patients For what concerns follow up studies it appears not to be possible to reduce the number of scanning areas Finally COVID 19 and post COVID 19 LUS data seem to show differences capable to confuse AI models that were not trained on post COVID 19 data supporting the hypothesis of the existence of LUS patterns specific to post COVID 19 patients A 12 areas acquisition protocol is recommended for both COVID 19 and post COVID 19 patients also during follow up 