High resolution CT is a more accurate detection method that we commonly use. This is because better software and hardware is needed on top of conventional CT. High resolution CT mainly uses the thinnest layer thickness and then a relatively small scan area to make a diagnosis of the lesion. Conventional CT is about 5-10mm layer thickness, and then high-resolution CT is about 1-1.5mm layer thickness, mainly used for examination of tiny nodules in lung and central system, such as skull base, and then cochlea and internal auditory tract. High-resolution CT is a thin-layer scan, and then a high-resolution algorithm is added. Because conventional CT is 5-10mm layer thickness, plus a soft tissue algorithm, high resolution CT is mainly 1-1.5mm layer thickness, plus a bone algorithm, so as to display small lesions more clearly, especially suitable for the examination of small nodules in the lung and the examination of the internal auditory canal, cochlea, inner ear, facial nerve, skull base nerve, which has great advantages.