MRI (Magnetic Resonance Imaging) is recommended for a comprehensive diagnosis when a CT of the brain is normal in the presence of an unknown cause. CT images can clearly show bone changes and brain hemorrhage, but they are not as good at detecting small metastatic foci in the central nervous system or showing spinal cord lesions as MRI. Based on the imaging principle and the characteristics of multi-parameter and multi-sequence imaging, MRI image has high soft tissue resolution and is capable of performing MR hydrography, MR angiography, MR diffusion imaging, MR functional imaging and MR spectroscopy, which makes the diagnosis of lesions more accurate and further shows the characteristics of the lesions, thus improving the diagnosis of the lesions and the ability of differential diagnosis. Compared with CT, MRI is more sensitive in detecting lesions and can detect small lesions at an early stage, such as pituitary microadenomas and spinal cord lesions. Please take into account the characteristics of your own condition and choose the appropriate examination method under the guidance of your doctor.