“Attenuation artifact” observed in a nuclear stress test is due to the reduction in the intensity / strength of signal when it travels through various body tissues of different densities, such as breast tissues, chest wall, and organs under the diaphragm.
What is attenuation defect?
Definition of attenuation defects.
Anterior wall attenuation was defined as reduced activity in the anterior segments with or without involvement of the anterolateral and/or anteroseptal segments.
What does artifact mean on a stress test?
Answer • An artifact, in this context, is anything that can keep the test from being interpreted correctly. People often think of medical tests as definitive — the stress test shows that either you have blockages in the arteries in your heart or you don’t — but it usually is not so clear.
What does diaphragmatic attenuation mean?
Abstract. Avoidance of falsely positive results depends on distinguishing reality from artifact, in turn depending on images of highest quality. In radionuclide cardiac imaging, an inferior wall artifactual defect, so called “diaphragmatic attenuation”, is particularly common and vexing.
What does attenuation correction mean?
Attenuation correction is a mechanism that removes soft tissue artifacts from SPECT images. Attenuation artifacts vary among patients, but the most common corrections are to artifacts associated with breast attenuation in women and diaphragmatic attenuation in men.
What does perfusion defect mean?
Areas that are damaged or don’t have good blood flow do not absorb the tracer. The damaged areas may be called “cold spots” or “defects.” A stress myocardial perfusion scan assesses blood flow to the heart muscle when it is stressed. The heart is usually “stressed” from exercise.
How do you read a myocardial perfusion scan?
A score of 1 represents an equivocal or mild reduction in perfusion, 2 represents moderately reduced perfusion, 3 represents severely reduced perfusion, and 4 indicates absent perfusion. The summed stress score for the left ventricle then is used to determine the risk for a future hard cardiac event (15).
What is a fixed defect on nuclear stress test?
A fixed defect is a perfusion defect present at stress and rest. Primary differential for a fixed defect includes scarring from infarction, chronically ischemic areas called hibernating myocardium, or attenuation.
What is a reversible perfusion defect?
Stress-induced perfusion abnormalities in regions that exhibit normal perfusion at rest are termed reversible perfusion defects, and such regions represent viable, ischemic tissue with blunted coronary blood flow reserve.
What does breast artifact mean?
Breast artifacts are the most frequent causes of false positive planar images in female subjects. Superimposition of breast tissue over the heart may result in linear areas of relatively increased activity, which is believed to be caused by small-angle scatter from the breast tissue fold.
What is abnormal myocardial perfusion?
Abnormal results may mean your heart isn’t pumping as well as it should. This might happen when you have heart damage or heart disease. Myocardial perfusion scans help us diagnose: Coronary artery disease. Heart failure.
What is a reversible defect in the heart?
A coronary stenosis is detected when a myocardial segment takes up the nuclear tracer at rest, but not during cardiac stress. This is called a “reversible defect.” Scarred myocardium from prior infarct will not take up tracer at all and is referred to as a “fixed defect.”
What is breast soft tissue attenuation artifact?
After a stress test, your physician may mention that you have “soft tissue artifact,” or “soft tissue attenuation.” What this means is that soft tissue, such as breast tissue, is showing up on the image created by the stress test.
How long should you do diaphragmatic breathing?
People should practice this breathing exercise for 5–10 minutes at a time, around three to four times each day. Once a person becomes comfortable with diaphragmatic breathing, they may start to practice the exercise while seated or standing.
What is summed difference score?
The summed difference score (SDS) represents the difference between the stress and rest scores and is taken to be an index of ischemic burden. The software processing and quantitative analysis were performed without reference to the initial visual interpretation or knowledge of the patient outcomes.
What is increased attenuation?
The increased lung attenuation pattern develops when the amount of air in the airspaces and in the lumen of the airways decreases (resulting from lung volume decrease or from partial or total filling of the airspaces) and when the soft tissue structures increase in size and/or amount, two phenomena that often occur
What is PET scan with CT for attenuation?
This method of attenuation correction is intended for use in a single scanner that combines volume-imaging (3D) PET with x-ray computed tomography (CT) for the purpose of providing accurately registered anatomical localization of structures seen in the PET image.
What does attenuation mean in MRI?
Abstract. Attenuation is the reduction of the intensity of an x-ray beam as it traverses matter. The reduction may be caused by absorption or by deflection (scatter) of photons from the beam and can be affected by different factors such as beam energy and atomic number of the absorber.
