Ultrasound artifacts

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Presentation Description

Concise discussion on usual artifacts encountered in ultrasound imaging

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Presentation Transcript

Imaging Pitfalls in Ultrasound:

Imaging Pitfalls in Ultrasound Dr. Varun

Introduction:

Introduction Quality of information obtained is determined by the user’s ability to recognize and avoid artifacts and pitfalls Many imaging artefacts are induced by errors in scanning technique or improper use of the instrument and are preventable Dr. Varun

Reverberation artifacts:

Reverberation artifacts Ultrasound signal reflects repeatedly between highly reflective interfaces that are usually, but not always, near the transducer. Gives false impression of solid structures in areas where only fluid is present Helpful – allow the identification of a specific type of reflector, like a surgical clip Dr. Varun

PowerPoint Presentation:

Dr. Varun

Reverberation artifacts:

Reverberation artifacts Can be reduced or eliminated by changing the scanning angle or transducer placement to avoid the parallel interfaces that contribute to the artifact. Dr. Varun

Refraction :

Refraction Bending of the sound beam so that targets not along the axis of the transducer are insonated . Their reflections are then detected and displayed in the image. This causes structures to appear in the image that actually lie outside the volume the investigator assumes is being examined. Dr. Varun

Refraction :

Dr. Varun Refraction

Refraction :

Dr. Varun Refraction

Side lobe artifacts:

Side lobe artifacts Side lobes may produce confusing echoes that arise from sound beams that lie outside the main ultrasound beam. Create the impression of structure or debris in fluid-filled structures May result in errors of measurement by reducing lateral resolution Repositioning the transducer and it’s focal zone or changing transducer differentiates the artifact from true echoes Dr. Varun

Side lobe artifacts:

Dr. Varun Side lobe artifacts

Side lobe artifacts:

Dr. Varun Side lobe artifacts

Shadowing:

Shadowing Marked reduction in the intensity of ultrasound deep to a strong reflector or attenuator Partial or complete loss of information due to attenuation of sound by superficial structures Dr. Varun

Enhancement :

Enhancement When an object attenuates less than surrounding tissues Failure of TGC applied to normal tissue to compensate properly for the attenuation of these structures producing the artifact. Dr. Varun

Shadowing and enhancement:

Shadowing and enhancement Two artifacts of clinical value As attenuation increases with frequency, effects of shadowing and enhancement are higher at higher frequencies The conspicuity of shadowing and enhancement is reduced by excessive beam width, improper focal zone placement, and use of spatial compounding. Dr. Varun

Multipath artifact:

Multipath artifact Created when the path of the returning echo is not the one expected, resulting in display of the echo at an improper location in the image Dr. Varun

Multipath artifact:

Multipath artifact Dr. Varun

Other artifacts:

Other artifacts Improper adjustment of system gain and TGC settings Many low level echoes are near the noise levels of the equipment Considerable skill and experience are needed to adjust instrument settings to display maximum information with minimum noise Poor scanning angles, inadequate penetration and poor resolution Dr. Varun

Other artifacts:

Other artifacts Careless selection of transducer frequency, lack of attention to focal characteristics of beam Loss of information from deep, low-amplitude reflectors and small targets. Dr. Varun

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