Contraindications to CT-enhanced examinations are as follows: 1. Patients with iodine drug allergy are prohibited from CT-enhanced examinations; 2. Patients with severe thyrotoxicosis are prohibited from CT-enhanced examinations; 3. Patients with cardiac, hepatic, renal and pulmonary insufficiency need to be vigilant when performing CT-enhanced examinations; 4. Diabetic patients taking biguanide preparations need to stop taking the drug 48 hours before and 48 hours after the examination; 5. Patients with myasthenia gravis need to be vigilant when performing CT-enhanced examinations, which can aggravate the patient’s symptoms and even other serious diseases.