The noninvasive diagnostic imaging process known as computed tomography (CT scan or CAT scan) creates horizontal, or axial, pictures of the body (commonly referred to as slices) using a mix of X-rays and computer technology. Any portion of the body, including the bones, muscles, fat, organs, and blood arteries, are clearly seen in a CT scan. Compared to traditional X-rays, CT scans are more detailed. The term High-Resolution CT (HRCT) of the chest, also known as HRCT chest or HRCT of the lungs, refers to a CT technique in which thin-slice images of the chest are acquired and then post-processed using a high-spatial-frequency reconstruction algorithm. For the evaluation of diffuse interstitial lung disease, this approach produces pictures of the lungs with excellent resolution.