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Artifacts: The downturn of CBCT image.

Nagarajappa AK, Dwivedi N, Tiwari R - J Int Soc Prev Community Dent (2015 Nov-Dec)

Bottom Line: Additionally, structures that do not exist in the subject may appear within images.To optimize image quality, it is necessary to understand the types of artifacts.This article aims to throw light on the various types of artifacts associated with CBCT images.

View Article: PubMed Central - PubMed

Affiliation: Department of Oral Medicine and Radiology, Hitkarini Dental College and Hospital, Jabalpur, Madhya Pradesh, India.

ABSTRACT
Cone-beam computed tomography (CBCT) has been accepted as a useful tool for diagnosis and treatment planning in dentistry. Despite a growing trend of CBCT in dentistry, it has some disadvantages like artifacts. Artifacts are discrepancies between the reconstructed visual image and the actual content of the subject which degrade the quality of CBCT images, making them diagnostically unusable. Additionally, structures that do not exist in the subject may appear within images. Such structures can occur because of patient motion, the image capture and reconstruction process. To optimize image quality, it is necessary to understand the types of artifacts. This article aims to throw light on the various types of artifacts associated with CBCT images.

No MeSH data available.


Aliasing pattern artifact
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Figure 6: Aliasing pattern artifact

Mentions: Aliasing in CBCT lies in the divergence of the cone beam. In each projection, the voxels close to the source will be traversed by more recorded “rays” [Figure 6] than those close to the detector. This causes aliasing which represents itself as line patterns (moire patterns), commonly diverging toward the periphery of the reconstructed volume. Aliasing may also be introduced by a crude interpolation between the back projection “lines” and the voxel they traverse. Ideally, the exact volume a voxel shares with the “line-fragment” crossing through it should be used to compute the intensity of the voxel. Owing to computational limitations, however, often only crude but fast approximations (i.e., the length of the fragment) enter the computation. This causes aliasing artifacts which can be avoided by a better interpolation scheme that is more closely conforming with the actual physical measurement conditions.[2101112]


Artifacts: The downturn of CBCT image.

Nagarajappa AK, Dwivedi N, Tiwari R - J Int Soc Prev Community Dent (2015 Nov-Dec)

Aliasing pattern artifact
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4697226&req=5

Figure 6: Aliasing pattern artifact
Mentions: Aliasing in CBCT lies in the divergence of the cone beam. In each projection, the voxels close to the source will be traversed by more recorded “rays” [Figure 6] than those close to the detector. This causes aliasing which represents itself as line patterns (moire patterns), commonly diverging toward the periphery of the reconstructed volume. Aliasing may also be introduced by a crude interpolation between the back projection “lines” and the voxel they traverse. Ideally, the exact volume a voxel shares with the “line-fragment” crossing through it should be used to compute the intensity of the voxel. Owing to computational limitations, however, often only crude but fast approximations (i.e., the length of the fragment) enter the computation. This causes aliasing artifacts which can be avoided by a better interpolation scheme that is more closely conforming with the actual physical measurement conditions.[2101112]

Bottom Line: Additionally, structures that do not exist in the subject may appear within images.To optimize image quality, it is necessary to understand the types of artifacts.This article aims to throw light on the various types of artifacts associated with CBCT images.

View Article: PubMed Central - PubMed

Affiliation: Department of Oral Medicine and Radiology, Hitkarini Dental College and Hospital, Jabalpur, Madhya Pradesh, India.

ABSTRACT
Cone-beam computed tomography (CBCT) has been accepted as a useful tool for diagnosis and treatment planning in dentistry. Despite a growing trend of CBCT in dentistry, it has some disadvantages like artifacts. Artifacts are discrepancies between the reconstructed visual image and the actual content of the subject which degrade the quality of CBCT images, making them diagnostically unusable. Additionally, structures that do not exist in the subject may appear within images. Such structures can occur because of patient motion, the image capture and reconstruction process. To optimize image quality, it is necessary to understand the types of artifacts. This article aims to throw light on the various types of artifacts associated with CBCT images.

No MeSH data available.