Cardiac hypodense shadow refers to the finding that the myocardial tissue around the heart exhibits varying degrees of features with lower gray values than other tissues through imaging examinations such as chest CT and coronary CTA. It is mainly common in myocardial infarction, cardiac tumor, cardiac thrombosis, etc. 1. Myocardial infarction: If the patient suffers from myocardial infarction, the myocardium leads to necrotic fibrosis, and the imaging examination can show a cardiac hypodensity shadow. 2. Cardiac tumors: When patients have cardiac tumors, CT examination can show abnormal cardiac hypodensity shadow. 3. Cardiac thrombus: Due to poor blood circulation and lipid accumulation, thrombus will appear in localized heart chambers, and CT examination will show cardiac hypodensity shadow. If cardiac hypodense shadow is found during the examination, you should consult a doctor in time to find out the cause of the disease and treat the symptoms.