Artifacts Flashcards
What is the definition of an artifact in imaging?
An error in imaging
Artifacts can lead to misinterpretations in ultrasound images.
What does the term ‘hyperechoic’ refer to?
Portions of an image that are brighter than surrounding tissues, or tissues that appear brighter than normal
Hyperechoic areas can indicate the presence of certain types of tissues or lesions.
What is meant by ‘hypoechoic’?
Portions of an image that are not as bright as surrounding tissues, or tissues that appear less bright than normal
Hypoechoic areas may suggest fluid-filled structures or certain types of lesions.
What does ‘anechoic’ describe?
An extreme form of hypoechoic, meaning entirely without echoes (echo-free)
Anechoic areas are typically associated with fluid, such as cysts.
What does ‘isoechoic’ mean?
Describes structures with equal echo brightness
Isoechoic structures can be challenging to differentiate from surrounding tissues.
Define ‘homogenous’ in the context of imaging.
A portion of tissue or an image that has similar echo characteristics throughout
Homogenous tissues often indicate uniformity in composition.
What does ‘heterogenous’ indicate?
A portion of tissue or an image that has differing echo characteristics throughout
Heterogeneous tissues may suggest the presence of various types of cells or structures.
List the six assumptions incorporated into the design of every ultrasound machine.
- Sound travels in a straight line
- Sound travels directly to a reflector and back
- Sound travels in soft tissue at exactly 1,540 m/s
- Reflections arise only from structures positioned in the beam’s main axis
- The strength of a reflection is related to the characteristics of the tissue creating the reflection
- The imaging plane is very thin
These assumptions are critical for accurate imaging and can lead to artifacts if violated.
What causes artifacts in ultrasound imaging?
- Violation of assumptions
- Equipment malfunction or poor design
- The physics of ultrasound
- Operator error
Understanding these causes can help in troubleshooting imaging issues.
True or False: Harmonic imaging reduces an image’s noise content.
True
Harmonic imaging enhances the signal-to-noise ratio.
Fill in the blank: Portions of an image that are not as bright as surrounding tissues are referred to as _______.
hypoechoic
Hypoechoic regions are significant in diagnosing various conditions.
What is indicated by the absence of anatomic reflectors on an image?
Less # or reflectors
This refers to a situation where expected anatomic features are not visible in the imaging.
What does vertical misregistration imply in imaging?
Artifact positioned deeper than the true anatomy
This indicates that there is a misalignment in the depth at which the artifact appears compared to the actual anatomy.
What does horizontal misregistration indicate?
Artifact displaced to the side of the true anatomy
This shows that the artifact is laterally misaligned from its true anatomical position.
What does it mean if anatomic reflectors appear with abnormal brightness?
Abnormal brightness of anatomic reflectors
This suggests that there may be an imaging artifact affecting the brightness of structures.
What is the consequence of anatomic structures appearing at incorrect depth?
Anatomic structures appear at incorrect depth
This can lead to misinterpretation of the imaging data.
What does it mean if anatomic structures appear in incorrect imaging planes?
Anatomic structures appear in the incorrect imaging planes
This indicates a potential error in image acquisition or processing.
What happens if anatomic structures do not correspond to echoes on the image?
Anatomic structures do not correspond to echoes on the image
This can indicate a failure in echo generation or processing.
What is shadowing in imaging?
A phenomenon where structures behind a highly reflective surface are obscured
This can lead to loss of diagnostic information in areas behind the shadowing object.
What is edge shadowing?
Shadowing by refraction
This occurs when the ultrasound beam is refracted at the edges of a structure, causing a shadow effect.
What does lateral resolution refer to?
The ability to distinguish two structures that are side by side
Higher lateral resolution allows for better differentiation of closely spaced structures.
What does axial resolution refer to?
The ability to distinguish two structures that are in line with the ultrasound beam
This is dependent on the spatial pulse length.
What is comet tail artifact?
An artifact that appears as a series of echoes following a strong reflector
Commonly seen with small, dense structures like surgical clips.
What is ring down artifact?
A series of echoes that appear as a continuous line from a strong reflector
Often associated with gas bubbles or certain types of lesions.
What is reverberation in ultrasound imaging?
Multiple echoes caused by sound bouncing between two strong reflectors
This can create false images and mislead interpretation.
What does mirror image artifact indicate?
An artifact that occurs when sound waves reflect off a strong interface and create a duplicate image
Often seen in structures near the diaphragm.
What is refraction in ultrasound?
Change in direction of sound waves as they pass through different media
This can lead to misinterpretation of the location of structures.
What are side lobes in ultrasound imaging?
Additional weaker beams emitted from the transducer
These can create artifacts and degrade image quality.
What are grating lobes?
Artifacts caused by array transducers that create multiple beams
They can lead to misrepresentation of the location of structures.
What does enhancement (hyperechoic) refer to?
Increased echogenicity behind a structure due to increased sound transmission
Commonly seen behind fluid-filled structures.
What is focal banding (hyperechoic)?
An artifact that appears as a band of increased echogenicity in specific focal areas
This can be mistaken for pathology.
What does shadowing (hypoechoic) refer to?
Decreased echogenicity behind a highly reflective structure
This can obscure underlying structures.
What does shadowing by refraction (hypoechoic) indicate?
Hypoechoic shadowing caused by refraction effects
This can mislead interpretation of structures behind the artifact.
What are speed errors in ultrasound imaging?
Errors that occur when the speed of sound in tissue is not accurately accounted for
This can lead to incorrect depth placement of structures.
What is range ambiguity artifact?
An artifact that occurs when echoes from deeper structures are misinterpreted as being from shallower structures
This can confuse the interpretation of the image.
What does slice or section thickness artifact refer to?
Artifact caused by the thickness of the ultrasound beam
This can lead to loss of detail in the image.
What is elevational resolution artifact?
Loss of detail due to the thickness of the imaging section
This affects the ability to visualize small structures in the elevation plane.
What is acoustic speckle?
Granular noise seen in ultrasound images due to interference of scattered sound waves
This can degrade image quality and visibility of structures.
What is multipath artifact?
An artifact caused by sound waves taking multiple paths before returning to the transducer
This can lead to misinterpretation of the location of structures.
What document should be referred to for a detailed list of artifacts?
Artifacts Table Document
This document provides comprehensive information on various imaging artifacts.
