CBCT Artifacts | Basic CBCT| CBCT basic understanding | Cone beam computed tomography
Summary
TLDRThis dental radiology video explores the various artifacts that can affect CBCT image quality, categorizing them into inherent, procedural, introduced, and patient motion artifacts. It explains how physical limitations, such as X-ray geometry and image reconstruction methods, contribute to inherent artifacts like cone beam artifacts and quantum noise. Procedural artifacts stem from under sampling and scanner issues, leading to misregistration and distortion. Introduced artifacts are caused by beam hardening, resulting in cupping and streaks. Lastly, patient motion artifacts can cause data misregistration, appearing as shading or streaking. The video also offers tips to minimize these artifacts for clearer dental imaging.
Takeaways
- π Dental radiology image artifacts in CBCT can be categorized into inherent, procedure-related, introduced, and patient motion artifacts.
- π Inherent artifacts stem from physical limitations such as the geometry of the X-ray cone, its trajectory, rotational arc, and the image reconstruction method of the software.
- π Quantum noise, or strict artifacts, and the cone beam effect are examples of inherent artifacts that can degrade image quality.
- π The partial volume artifact occurs in both CT and CBCT, where a single voxel contains multiple tissue densities, leading to an averaged, inaccurate representation.
- π Procedural artifacts can result from under-sampling, causing misregistration and streaking artifacts, or scanner issues leading to circular artifacts.
- π Beam hardening artifacts occur when the X-ray beam's energy changes after passing through dense objects, causing distortions in the image of metallic structures.
- π₯ To mitigate beam hardening artifacts, adjust the field size, modify patient positioning, or separate the dental arc to avoid scanning metallic dental implants or restorations.
- π« Removing metallic objects like jewelry before scanning can help reduce peripheral beam hardening effects on the region of interest.
- πββοΈ Patient motion artifacts arise from movement during the scan, leading to misregistration and potential shading or streaking in the image.
- π’ The video emphasizes the importance of understanding and managing these artifacts to ensure accurate diagnostic imaging in dental radiology.
Q & A
What are the main factors that affect CBCT image quality?
-The main factors affecting CBCT image quality are image artifacts and distortions, which can be unrelated to the object or artificially appearing on the image but not part of the tissue being examined.
How can dental radiology image artifacts in CBCT be classified?
-Dental radiology image artifacts in CBCT can be classified into inherent artifacts, procedure-related artifacts, introduced artifacts, and patient motion artifacts.
What are inherent artifacts in CBCT?
-Inherent artifacts arise from limitations in physical processes due to the geometry of the X-ray, such as the cone-beam effect, trajectory, rotational arc, and image reconstruction method of the software.
What is the cone beam effect and how does it affect image quality?
-The cone beam effect, or V artifact, occurs because the X-ray beam is cone-shaped and has divergence. This results in less data collection at the periphery compared to the center, leading to streaking artifact and noise at the edges of the image.
What is a partial volume artifact and how does it appear in CBCT?
-A partial volume artifact occurs when different tissue densities are present in one voxel, causing the final density displayed to be an average rather than the real density of the individual tissues.
What are procedure-related artifacts and how do they occur?
-Procedure-related artifacts include under sampling artifacts and scanner-related artifacts. They occur when there is a large interval between projections or sections, causing misregistration of data and visible artifacts like fine hypodense and hyperdense strips.
What is a circular artifact in CBCT and what causes it?
-A circular artifact in CBCT is caused by a detector being out of calibration, resulting in a constantly reading error at each angulation of the tube, which manifests as a circular pattern in the image.
How does beam hardening affect CBCT images?
-Beam hardening occurs when the X-ray beam passes through dense objects, causing lower energy photons to be absorbed and the mean energy to increase. This can result in artifacts such as distortion in the image of metallic structures and dark streaks between dense objects.
What are introduced artifacts and how can they be reduced?
-Introduced artifacts include cupping artifact, streaks, and dark bands caused by beam hardening. They can be reduced by adjusting the field size, modifying patient position, or separating the dental arc to avoid scanning regions with metallic objects.
What are motion artifacts and how do they appear in CBCT images?
-Motion artifacts are caused by patient movement during the scan, leading to misregistration of data and appearing as shading or streaking in the image, sometimes causing a double contour of bones.
Why is it important to remove metallic objects before scanning in CBCT?
-Removing metallic objects like jewelry before scanning in CBCT is important to reduce peripheral beam hardening effects that can superimpose on the region of interest and degrade image quality.
Outlines
π Understanding CBCT Image Artifacts
This paragraph discusses the various types of artifacts that can affect the quality of CBCT (Cone Beam Computed Tomography) images in dental radiology. The speaker, Farida, introduces the concept of image artifacts, which are distortions or errors unrelated to the actual tissue being examined. The artifacts are categorized based on their causes: inherent, procedure-related, introduced, and patient motion artifacts. Inherent artifacts stem from limitations in the physical processes, such as the geometry of the X-ray beam and the image reconstruction method. Specific types of inherent artifacts include scanner artifacts, quantum noise, cone beam effect, and partial volume artifacts. The paragraph also explains the causes and effects of each type of artifact, providing insights into how they can be identified and potentially mitigated in dental imaging.
π Addressing Beam Hardening and Motion Artifacts in CBCT
The second paragraph delves into the specific types of artifacts related to the X-ray beam and patient movement. Beam hardening artifacts occur when the X-ray beam passes through dense objects, causing a change in the mean energy of the beam and leading to distortions in the image. This can result in cupping artifacts, streaks, and dark bands. To reduce these effects, the speaker suggests techniques such as reducing the field size, modifying patient position, and removing metallic objects before scanning. Motion artifacts, caused by patient movement during the scan, can lead to misregistration of data and appear as shading or striations in the image. The speaker emphasizes the importance of patient stability during the scanning process to minimize these artifacts. The paragraph concludes with a call to action for viewers to subscribe, share, and stay updated for future educational content.
Mindmap
Keywords
π‘Image Artifact
π‘Cone Beam Computed Tomography (CBCT)
π‘Quantum Noise
π‘Cone Beam Effect
π‘Partial Volume Artifact
π‘Under Sampling Artifact
π‘Scanner Artifact
π‘Beam Hardening Artifact
π‘Motion Artifact
π‘Metallic Artifact
Highlights
Image artifacts in CBCT can be classified according to their etiology.
Inherent artifacts arise from limitations in physical processes.
Scanner artifacts occur when X-ray photons are diffracted from their original path.
Quantum noise is a type of inherent artifact that affects image quality.
Cone beam effect or a V artifact is caused by the geometry of the X-ray beam.
Partial volume artifact occurs when different tissue densities are present in one voxel.
Procedural related artifacts include under sampling artifacts and scanner related artifacts.
Under sampling artifact can cause misregistration of data at sharp edges.
Circular artifact or ring artifact occurs when a detector is out of collaboration.
Introduced artifacts include beam hardening artifacts like cupping and streaks.
Beam hardening artifact can cause distortion in the image of metallic structures.
Dark streak artifact occurs between two dense objects due to beam hardening.
To reduce beam hardening artifacts, one can modify the field size or patient position.
Metallic objects like jewelry should be removed before scanning to reduce beam hardening effect.
Motion artifacts are caused by patient movement and can appear as shading or streaking.
Double contour of bones can be seen with motion artifacts.
Transcripts
foreign
[Music]
the fundamental factories that affect
the cbcd image quality is the image
artifact and artifices any Distortion or
error in the image that is unrelated to
the object or something artificial that
appears on the image but is not a part
of the tissue being examined
hi there I'm farida if you're new here
welcome if you've been here welcome back
to the dental radiology
image artifacts in cvcd can be
classified according to their etiology
inherent artifacts procedure related
introduced artifacts and patient motion
artifacts
today's classification is
the book of why dinosaur or Radiology
principles and interpretation
inherent artifacts arise from limitation
in physical process due to geometry of
the X-ray that is like a cone
reduce trajectory rotational Arc
and image reconstruction method of the
software
these are the subtitles of the inherent
artifacts
scanner artifact
x-ray photons are diffracted from their
original path after interacting with the
object because CBC use area detectors
the scanner photons are absorbed and
decrease the image quality we call it
quantum noise so what we see
is strict artifacts
or we can have a greatness appearance is
like small dots on the image
cone Bean effect or a v artifact
of course because the beam is like a
cone and we have divergency of the X-ray
beam
when the X-ray rotates showing two
position of the exterior tube zero
degree and 180 degree the center Parts
get maximum amount of data collection by
the detector for reconstruction but the
peripheral the amount of data collection
is less the red graph shows the effect
of and educate data in the peripheral
that would be in the superior and the
inferior
it is seen at the edges or the
peripheral portion of the image the
result is stricking artifact and noise
in the peripheral
partial volume artifact this artifact is
seen in both CT and cbct
when one soft tissue is presented in a
single voxel the density that is seen
shows the exact density of the soft
tissue
when the voxel size is larger than the
object so different tissue density are
present in one book cell so the final
density that shows will be an average
and not showing the real density for
example a voxel contain both bone and
adjacent soft tissue but the display is
neither bone or soft tissue
procedural related artifacts contain
under sampling artifacts and scanner
related artifacts
under sampling artifact when we have
large interval between projection
or the section
and can cause misregistration of the
data in the sharp edges The View we see
can be called a lysine artifact fine
strips if you're like radiating from the
edges of dense structures like the skull
bone on this cbct particularly on the
peripheral we can see fine hypotens and
Hyper dense strips
if you are to be radiating from the
edges of the bone it can also be called
the moyer pattern
circular artifact or ring artifact if
one of the detectors is out of
collaboration like we have a bad pixel
the detector will give a constantly
reading error at each angulation of the
tube resulting a circular artifact
introduced artifacts
that is the beam parting artifact
contains two categories cupping artifact
and streaks and dark bonds being
hardening artifact when x-ray beam
passes through a dense object like a
crown restoration lower energy photons
are absorbed but higher energy photons
pass through the mean energy increase so
the beam becomes hard and it penetrates
two types of artifacts can be the result
from this effect
copying artifact Distortion in the image
of metallic structures
x-ray passed through the mid portion of
the object and are hardened more than
those passing the edges
because soft
extra photons are absorbed more
so we can see the Distortion in the
image of metallic structures
and we have this strict
dark artifact
that happens
between two dense objects
like
um
dental implants and dental restoration
that we can also call them extension
artifact or missing Valley artifact
so we have a hard x-ray that can burn
that part of our image and manifest as
dark stricts between two highly
alternation structures
to reduce the beam Harding artifact we
can reduce the field size or we can
modify the patient
or we can separate the dental Arc to
avoid scanning region like dental
implants or dental Restorations
that are metallic
and it's also important to remove
metallic objects like jewelry before
scanning to reduce the peripheral beam
Harding effect that can be superimposed
on the region of interest that is being
imaged
motion artifact that would be the
patient artifacts due to the patient
movement and can cause misregistration
of the data and can appear as shading or
striking
we can see double Contour of the bones
with double strict
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