Cone Beam CT - Basics II Flashcards
How many basis images does the CBCT capture?
range of 100 to 600 basis images per rotational scan
What are the types of image software that can be used to manage volumetric data sets?
a. proprietary (property of a vendor)
b. universal – DICOM (Digital Imaging and Communications in Medicine)
What is a volumetric data set?
the package of images constructed by an imaging software program which then displays various image reconstructions
What is DICOM?
- standard information transfer method (file format) for transferring images and associated information between devices manufactured by various vendors
- Digital Imaging and Communications in Medicine
What is HIPAA?
Health Insurance Portability and Accountability Act
Multiple third-party software available for imaging DICOM Compatible CBCT volumetric data such as…
- Anatomage InVivo 3D
- CareStream 3D
- Cybermed 3D
- Dolphin 3D
- (Infinitt) Xelis Dental, Xelis 3D
- Keystone EasyGuide 3D
- NobelClinician
- OnDemand 3D
- OsiriX DICOM viewer
What is the most widely used DICOM viewer?
OsiriX DICOM Viewer
What are the features of the OsiriX DICOM Viewer?
- most widely used DICOM viewer because of global recognition and longevity
- One of first to fully support the DICOM standard for easy integration
Non-DICOM Compatible 3D software include…
*Materialise SurgiCase CMF
*Simplant (Materialise)
*Sirona – SICAT ($~400/kit)
*Morita – i-Dixel
Only ________ projection data files are transferred to and stored in the UMKC SOD MiPACS server
DICOM
Proprietary (Native) files are stored in the…
capture CPU or its server
Why are multiple forms of datasets a problem?
- Image transfer is not as simple as transferring one or a series of intraoral images
- One transfers 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.
_______ image reconstruction capacity dwarfs the ranges of intraoral, panoramic and skull images
CBCT
____ image reconstructions are not typically stored and transferred
2D
Entire volumetric data sets are transferred so practitioners…
– are not limited to a limited number of reconstructions
– can determine their own preferred range of images needed for their diagnostic and treatment needs
How do multiple forms of datasets inhibit access to health care?
- limiting the access to the patient’s information
- increasing cost of treatment
- delaying time of treatment
What are the types of inherent artifacts in CBCT?
- Beam Hardening
- Streaking
What is beam hardening?
- a reconstruction artifact in CT due to the total absorption of low energy photons by metal objects
- 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
Effect of beam hardening simulating peri-implantitis and alveolar bone defects in the _________ and _________ reconstructions.
cross-sectional and parasagittal
What is a streak artifact?
streak artifact creates the outline of a “ghost” implant (as well as other radiopaque streak outlines) in the cross sectional reconstruction
The _________ artifact makes it more
difficult to discern the validity of the cortical bone outlines.
streak
How does a streak artifact form?
- X-rays are heavily attenuated after passing through metal objects which results in very weak signals reaching the detector
- 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 low density (soft tissue) structures
What is wrong with this image?
beam hardening
What is wrong with this image?
streak artifact
What is MPR?
multi-planar reconstruction
What is 2D panoramic reconstruction?
● Imaging software packages can reconstruct panoramic
images from the storage data
● CBCT scan is not indicated solely for panoramic imaging
What are the different applications of CBCT image reconstruction?
- MPR
- Panoramic
- Volume rendering (3D)
- TMJ
- Implant Planning
