“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 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 is an artifact in the heart?

Electrocardiograph (EKG) artifacts are defined as EKG abnormalities, which are a measurement of cardiac potentials on the body surface and are not related to electrical activity of the heart. As a result of artifacts, normal components of the EKG can be distorted.

What does attenuation from breast tissue mean?

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.

What is attenuation in spect?

Attenuation correction is a mechanism that removes soft tissue artifacts from SPECT images. … The size of the patient and the amount of tissue between the heart and the detector lead to attenuation artifacts that adversely affect the image of the heart.

What does diaphragm 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 causes attenuation artifact?

“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 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 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 are soft tissue artifacts?

Background: Soft tissue artefact is the most invalidating source of error in human motion analysis using optoelectronic stereophotogrammetry. It is caused by the erroneous assumption that markers attached to the skin surface are rigidly connected to the underlying bones.

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What is artifacts in ECG?

Electrocardiographic artifacts are defined as electrocardiographic alterations, not related to cardiac electrical activity. As a result of artifacts, the components of the electrocardiogram (ECG) such as the baseline and waves can be distorted. Motion artifacts are due to shaking with rhythmic movement.

What causes artifacts in ECG?

Causes of electrical artifacts on ECGs are manifold. External artifacts are usually caused by line current, which has a frequency of 50 Hz or 60 Hz. Internal electrical artifacts can be caused by tremors, muscle shivering, hiccups or, as in the present case, medical devices.

Which situation can result in artifact on the ECG?

Artifact on the electrocardiogram can result from a variety of internal and external causes from Parkinsonian muscle tremors to dry electrode gel. Most of the time it will be obvious that you are dealing with artifact and troubleshooting the problem will be straight forward.

What is attenuation map?

Reliable attenuation correction methods for emission tomography require determination of an attenuation map, which represents the spatial distribution of linear attenuation coefficients for the region of the patient’s anatomy that is included in the radionuclide imaging study.

Why do we use correction for attenuation?

Correction for attenuation (CA) is a method that allows researchers to estimate the relationship between two constructs as if they were measured perfectly reliably and free from random errors that occur in all observed measures.

What is the difference between SPECT and pet?

The main difference between SPECT and PET scans is the type of radiotracers used. While SPECT scans measure gamma rays, the decay of the radiotracers used with PET scans produce small particles called positrons. A positron is a particle with roughly the same mass as an electron but oppositely charged.

What does artifact mean on ultrasound?

Artifacts are any alterations in the image which do not represent an actual image of the examined area. They may be produced by technical imaging errors or result from the complex interaction of the ultrasound with biological tissues.

What causes artifacts in ultrasound?

US artifacts arise secondary to errors inherent to the ultrasound beam characteristics, the presence of multiple echo paths, velocity errors, and attenuation errors.

How do ultrasound artifacts affect ultrasound image?

Ultrasound artifacts The following artifacts are common in ultrasound imaging: The ultrasound image displays non-existing structures. The ultrasound image does not display existing structures. The ultrasound image misrepresents the echogenicity of structures.

What is a perfusion defect?

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.

What does motion artifact mean?

When a patient moves, it can cause distortion on the image, which is referred to as a motion artifact. Motion artifacts may appear as a blurring of contrast or edges, replication of part or all of a structure, signal loss or undesired strong signals.

Which artery is the most common to have blockage?

Although blockages can occur in other arteries leading to the heart, the LAD artery is where most blockages occur.

What percent of blockage requires a stent?

By clinical guidelines, an artery should be clogged at least 70 percent before a stent should be placed, Resar said. “A 50 percent blockage doesn’t need to be stented,” he said.

How fast does your heart beat during a stress test?

Your target heart rate during a stress test depends on your age. For adults, the maximum predicted heart rate is 220 minus your age. So, if you’re 40 years old, the maximum predicted heart rate is 220 – 40 = 180.

Is exercise good for LBBB?

After three months of regular exercise training with 30-minute sessions per day for five days a week, the patient’s symptoms improved with development of LBBB and chest pain at a considerably higher heart rate of 150 bpm (Figure 3). The morphology of the LBBB remained the same.

Is 9 minutes on a treadmill stress test good?

In conclusion, for patients able to manage a 9-minute Bruce protocol, presence/absence of symptoms or electrocardiographic changes is a poor predictor of MPS findings. Irrespective of test findings, however, subsequent cardiac risk is extremely low.

What causes fixed defect on stress test?

A fixed perfusion defect with preserved wall motion can be attributed to soft tissue attenuation artifact, such as breast attenuation or inferior wall attenuation caused by the diaphragm, ascites, large pleural effusions, or by other abdominal visceral structures.

What is soft tissue around the heart?

The heart muscle has a tight covering that surrounds it, a lining sac called the pericardium (peri=around+cardium=heart).

What qualifies as an artifact?

Definition of artifact 1a : a usually simple object (such as a tool or ornament) showing human workmanship or modification as distinguished from a natural object especially : an object remaining from a particular period caves containing prehistoric artifacts.

How can you reduce artifacts?

1. Minimize the degree of motion. a. The importance of simple instruction/education of the patient to hold still while the scanner is making noise should not be underestimated. …
2. Suppress signal from moving tissues. a. …
3. Adjust imaging sequences and parameters. a. …
4. Detect and compensate for motion.

What is sinus tachycardia with artifact?

Sinus tachycardia refers to a faster-than-usual heart rhythm. Your heart has a natural pacemaker called the sinus node, which generates electrical impulses that move through your heart muscle and cause it to contract, or beat.