Pleurisy and Empyema Pleural diseases are common and represent a significant contribution to the workload of emergency department. Patients with pleural effusions may be asymptomatic; however, they generally present with symptoms such as pleuritic chest pain or dyspnea. Imaging of Spontaneous Pneumothorax Spontaneous pneumothorax is a relatively common cause of thoracic pain in young, thin, and tall males without preexistent lung diseases, although it is known that its occurrence is due to the rupture of underlying small sub-pleural bullae and blebs at the lung apices, found at thoracoscopy or detected on CT. Signs and symptoms may be nonspecific, and often the clinical suspicion requests a diagnostic confirmation, primarily based on X-rays and, in complicated cases, on CT: in this chapter, the authors will review the radiological and CT signs of spontaneous pneumothorax and will discuss signs which can predict its recurrence and informations which strongly influence the management and the treatment choice. © Springer International Publishing Switzerland 2017.