Sarcoidosis is a chronic disease involving lung and mediastinum in more than 90% of cases. Five to 25% of thoracic sarcoidosis are complicated by a severe fibrotic lung disease. Computed tomography (CT) is critical for the diagnosis of thoracic sarcoidosis as well as for therapeutic management. Repeated CT examinations, sometimes all life long, raise the issue of the cumulative radiation dose and subsequent risk of cancer, thus pushing the need for imaging techniques using low or no radiation dose. Based upon tube voltage and current reduction as well as iterative recontsruction, ultra-low dose CT (ULD CT) allows to lower the dose up to that of a traditional chest X-ray. Magnetic resonance imaging (MRI) using Ultrashort echo time (UTE) enables lung parenchyma imaging with high signal-to-noise and spatial resolution.