Harms of overuse of<unk>  include radiation exposure and the possibility of finding then seeking treatment for a clinically insignificant pulmonary embolism which ought not be treated. Adverse reactions A reaction may occur whenever iodine contrast is injected. These reactions range in severity and it is difficult to predict if they will occur. With the current practice of using low-osmolar contrast these adverse reactions only occur in ~0.1% of cases. The severity of the reaction can be broken down into three groups: * Mild - no treatment required: nausea, vomiting, and/or hives. * Moderate - requires treatment: severe hives, lightheadedness or brief loss of consciousness, mild bronchospasm, and/or increased heart rate. * Severe - requires immediate treatment: severe bronchospasm, throat swelling, seizure, severe low blood pressure, and/or cardiac arrest. A patient with a history of allergy to contrast may be advised to take medications such as corticosteroids or histamine (H1) blockers before<unk>  to lessen the risk of allergic reaction or to undergo a different exam that does not call for contrast material injection. Patients should also be well hydrated in order to minimize possible adverse effects of contrast. Contrary to popular belief there is no correlation between seafood allergies and reactions to iodine contrast, as shown by many recent studies. Kidneys Historically it has been thought that contrast material can lead to contrast-induced nephropathy (also called CIN) in any patient. However, recent studies have shown that the risk of kidney injury caused by contrast agent in patients with no history of kidney problems occurs extremely infrequently. The use of<unk>  in people with kidney failure, kidney disease or long-standing severe diabetes should be weighed carefully as the use of IV iodine contrast material may further harm kidney function. The decision not to use contrast agents must be weighed against the possibility of misdiagnoses if contrast is not used. Radiation Compared with other imaging modalities,<unk>  is associated with a significant dose of ionizing radiation. Varying significantly with patient age, sex, and exam protocol, radiation risk models predict coronary<unk>  to increase lifetime cancer risk. The radiation risk presented by<unk>  is much lower than invasive angiography procedures.<unk>  should not be performed in patients who are pregnant as the contrast and radiation may lead to harm to the fetus. The extent of harm to the fetus has not been fully determined.
Computed tomography angiography
Radionuclide angiography
Magnetic resonance angiography
Microangiography
Angiography
Carbon dioxide angiography
Digital subtraction angiography
Digital variance angiography