Whether CT and MRI are necessary at the same time depends on the patient’s condition, as follows: 1. CT is more sensitive to lung diseases, and in case of cough and chest discomfort, CT chest scan can effectively observe the lung, mediastinum, chest wall and chest cavity; 2. If cough is accompanied by abdominal and thoracic spine discomfort, MRI is also needed to observe the spinal canal and other tissue lesions in detail; 3. If nasopharyngeal carcinoma is suspected, CT examination reveals occupancy, and then MRI can better observe the extent of lesion invasion and metastasis.