CBCT – 2 Flashcards

1
Q

CBCT Basis-image Capture

A

Two basis-image capture sequences as the machine
rotates counterclockwise from Position 1 to Position 2
scans routinely capture in the range of 100 to 600 basis
images per rotational scan.

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2
Q

CBCT Image Production
Multiple — projections form the —

A

basis image
projection data.

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3
Q

CBCT Image Production
A volumetric data set is then the

A

package of images constructed by an imaging
software program which then displays various image reconstructions

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4
Q

CBCT Image Production
The — reconstruction is the primary reconstruction when volumetric data
is first accessed by a viewing software program

A

multiplanar

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5
Q

CBCT Image Production
●The number and types of reconstructions (images) are dependent on the

A

power of
the program as specified by the software manufacturer(s).

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6
Q

File Formats

A
  1. Original scan data (projection data) forms
    the volumetric data set
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7
Q

File Formats
2. Scanner software can either store the
volumetric data in either the
(2)

A

a. proprietary format (unique to vendor)
b. universal format – DICOM
(Digital Imaging andCommunications
in Medicine)

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8
Q

proprietary format (unique to vendor)

A

InVivo format

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9
Q

universal format – DICOM
(Digital Imaging and Communications
in Medicine)

A

EggViewer format

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10
Q

DICOM

A
  • standard information transfer method
    (file format) for transferring images
    and associated information between
    devices manufactured by various
    vendors
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11
Q

DICOM
stands for

A

Digital Imaging and Communications
in Medicine

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12
Q

Multiple third-party software available for
imaging DICOM Compatible CBCT
volumetric data

A
  • Anatomage InVivo 3D
  • CareStream 3D
  • Cybermed 3D
  • Dolphin 3D
  • (Infinitt) Xelis Dental, Xelis 3D
  • Keystone EasyGuide 3D
  • NobelClinician
  • OnDemand 3D
  • OsiriX DICOM viewer
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13
Q

OsiriX DICOM Viewer
most widely used DICOM viewer because
of

A

global recognition and longevity

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14
Q

OsiriX DICOM Viewer
One of first to fully support the

A

DICOM
standard for easy integration

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15
Q

Non-DICOM Compatible 3D software
(4)

A
  • Materialise SurgiCase CMF
  • Simplant (Materialise)
  • Sirona – SICAT ($~400/kit)
  • Morita – i-Dixel
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16
Q

Only— data files
aretransferred to and stored in the UMKCSoD MiPACS server

A

DICOM projection

17
Q

Proprietary (Native) files are stored in the

A

capture CPU or its server

18
Q

skipped
Why are multiple forms of
datasets a problem?
(3)

A
  • For final storage, proprietary
    volumetric data sets were used
    by 26% of respondents (n =
    68)
  • Of the 74% storing in a DICOM
    format, 66% also stored in the
    proprietary format
  • 26 % + [74% x 0.66],
    26 % + 48.9% = 74.8% of
    respondents save the
    proprietary format
19
Q

Why is this a problem?
It inhibits access to health care by:
(3)

A
  • limiting the access to the
    patient’s information
  • increasing cost and
  • delaying time of treatment
20
Q

Why is this a problem?
* Image transfer is not as simple
as transferring one or a series
of intraoral images
* One transfers …

A

an entire data
set so the user may access the
image files to construct the
selected images needed. The
images needed will vary
between different practitioners

21
Q

Why is this a problem?
* CBCT image reconstruction capacity — the ranges of
intraoral, panoramic and skull images

22
Q

Why is this a problem?
* 2D image reconstructions are not typically stored and
transferred
* Entire volumetric data sets are transferred so practitioners
(2)

A

– are not limited to a limited number of reconstructions
– can determine their own preferred range of images needed for their
diagnostic and treatment needs

23
Q

Inherent Artifact
(2)

A
  • Beam Hardening
  • Streaking
24
Q

Beam Hardening

A
  • is a reconstruction artifact in CT due to the total
    absorption of low energy photons by metal objects
  • however, high energy photons in the
    heterogenous x-ray beam will create a signal in
    tissues adjacent the metal structure in the
    backprojection algorithm and these areas will be
    “burned out” thus creating dark areas
25
streak artifact creates the outline of a
“ghost” implant (as well as other radiopaque streak outlines) in the crosssectional reconstruction. The streak artifact makes it more difficult to discern the validity of the cortical bone outlines.
26
Streak Artifact X-rays are heavily attenuated after passing through metal objects which results in
very weak signals reaching the detector
27
Streak Artifact * metal shadows in the raw projection data will then introduce streak artifact in the backprojection algorithm reconstructions which introduces the metal streak artifact primarily in --- structures
low density (soft tissue)
28
CBCT: Image Reconstruction Applications (5)
* MPR * Panoramic * Volume rendering (3D) * TMJ * Implant Planning
29
CBCT Image Capture and Data Management: * Basis Image(s) * Projection Data – * Volumetric Data Set –
total set of basis images image files managed by image software
30
* Volumetric Data Set – image files managed by image software – Types (2)
a. proprietary (property of a vendor) b. universal – DICOM
31
2D Panoramic Reconstruction ● Imaging software packages can reconstruct panoramic images from the ● CBCT scan is not indicated solely for
storage data panoramic imaging