What methods are available to correct for attenuation artifact? Two common methods are used to correct for attenuation artifact. One method directly corrects this problem by using an external radioactive source that is transmitted through the patient. This source is used to map the patient’s body structures to assess their ability to attenuate photons. By …
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What are the contraindications for pharmacologic vasodilatory and adrenergic agonist stress tests? Pharmacologic vasodilatory stress tests are not performed in patients with severe reactive airway disease, particularly when a patient has active wheezing on physical examination. Patients who use inhalers but who otherwise have stable airway disease can often safely undergo these stress tests. Any …
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What is the Implication of a nonreversible defect on SMPI? A nonreversible defect implies that there is a lack of myocardial perfusion during the rest and stress components of the scan (i.e., there is no difference between the two scans). Nonreversible defects can often be caused by artifact, such as when part of the heart …
Which territories are supplied by which coronary arteries? The three main branches of the coronary arteries are the left anterior descending artery (LAD), the left circumflex artery (LCx), and the right coronary artery (RCA). The LAD supplies the anterior wall, including the anterolateral region; the interventricular septum; and, in most cases, the apex. The RCA …
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Conditions under which an exercise stress test should be stopped • The patient cannot continue because of dyspnea, chest pain, fatigue, or musculoskeletal problems. • The patient has a significant hypertensive response. • The patient develops ST segment depression greater than 3 mm. • The patient develops ST segment elevation, heralding a possible myocardial infarction. • The patient develops a potentially …
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Should patients taking medications that can affect the heart be given stress tests? Generally, any patient can undergo a cardiac stress test. In patients taking medications for blood pressure, such as β-blockers or calcium channel blockers, the medication may prevent the patient from achieving the necessary heart rate. In such patients, it is recommended that …
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What are contraindications for an exercise stress test? Any patient with significant musculoskeletal problems that would prevent him or her from achieving a maximal heart rate should undergo pharmacologic stress testing. Patients with certain ongoing dysrhythmias, such as ventricular tachycardia, supraventricular tachycardia, new-onset atrial fibrillation, or heart block, should receive treatment for those dysrhythmias before …