Challenging unknown thoracic imaging cases are common in every day private and academic practice settings. This course highlights how the ability to analyze and interrogate imaging findings varies with level of training and years of experience. The course provides a succinct overview of challenging cases in thoracic imaging, covering multiple disease categories, highlighting different techniques and search patterns that can be used to approach such cases. The speakers focus on the analysis of unknown imaging case findings and the synthesis of such findings to establish the most appropriate working differential diagnosis and probable case diagnosis.