Chapter 27: Three-Dimensional Digital Imaging

Anatomic features within the FOV provide accurate dimensional measurements, _________ ratio relationship

1:1

In CBCT machine, scan times vary between 7 and _____ seconds

30

name the essential specialized equipment necessary for three-dimensional digital imaging.

A CBCT machine, a computer, and various types of viewing software.

_________ plane looks at the patient from behind -series of images starting at the back of the head and moving towards the face (anteroposterior view).

Coronal

Raw data is three-dimensional in volume and forms a "stack" of axial images—also known as ____________ images

DICOM

___________ plane will allow evaluation of the patient's structures from side- to-side in a series of images starting at one ear and moving to the other.

Sagittal

True or False: Come-beam data has a 2:1 relationship with the anatomy.

false

True or False? Compared with traditional computed tomography (CT) procedures, cone-beam imaging provides A higher radiation dose for the patient.

false

What are the three planes available in 3D imaging?

■ axial ■ coronal ■ sagittal

Smaller voxels = higher resolution = higher ______________ dose

radiation

True or False: A short exposure time decreases the chances for motion artifacts to occur, as well as encouraging a high level of patient cooperation.

true

True or False: If the field of view is small, findings or pathology in other regions of the oral and maxillofacial complex may be missed.

true

True or False: Three-dimensional imaging provides an in-depth image that gives dental professionals a more complete interpretive image than with two-dimensional scans of traditional imaging.

true

True or False: Three-dimensional imaging serves a number of diagnostic purposes for dental practitioners.

true

Spatial resolution

A measurement of pixel size in multi planar reconstruction.

Three-dimensional volume rendering

A three-dimensional shape that is created from two-dimensional images.

Coronal plane

A vertical plane that divides the body into anterior and posterior sides; runs perpendicular to the ground.

Sagittal plane

A vertical plane that divides the body into right and left sides; runs perpendicular to the ground.

Which organization recommends that CBCT images be interpreted only by a board- certified oral and maxillofacial radiologist or by the dentist with adequate training and/or expertise?

American Academy of Oral and Maxillofacial Radiology (AAOMR)

_________ plane evaluates the patient from below in a series of images starting at the chin and moving to the top of the head (axial view).

Axial

Manufacturers of CBCT provide settings for a variety of _________ sizes for diagnostic purposes

FOV

actors that can be altered are :

FOV size and resolution

Which non-profit organization developed standards applicable to the minimum requirements for optimum patient care when using dental computed tomography? **To receive this accreditation, dentist must satisfactorily pass a peer review process and other requirements**

Intersocietal Accreditation Commission (IAC)

Cone-beam computed tomography (CBCT)

Term used to describe computer - assisted digital imaging in dentistry; this imaging technique uses a cone shaped x-ray beam to acquire information and present it in three dimensions.

Cone-beam volume tomography (CBVT)

Term used to describe computer-assisted digital imaging in dentistry, used interchangeably with cone-beam volume imaging (CBVI); these terms are used to differentiate this procedure from medical computed tomography (CT).

Field of View (FOV)

The area that can be captured when performing imaging procedures.

Contrast resolution

The number of gray-scale colors available to be chosen for each pixel in the image.

Multiplanar reconstruction (MPR)

The reconstruction of raw data into images when imported into viewing software to create three anatomical planes of the body.

Voxel

The smallest element of a three - dimensional image.

DICOM data

The universal format for handling, storing, and transmitting three - dimensional images.

__________ are assigned a number and a color on the grayscale

Voxels

why is it important for the dental professional who uses CBCT to be a board-certified oral and maxillofacial radiologist or a dentist with adequate training or experience?

You want to make sure they accurately recognize findings and pathology outside of the region of interest, specifically outside the maxilla and mandible. failure to do so could result in poor treatment outcomes for the dental provider and, more importantly, negative consequences for patients.

An area of high attenuation that could stop radiation from reaching the receptor could include which restoration(s)? a. metal crown b. bridge c. large amalgam restoration d. all of the above

d. all of the above

Which is/are advantage(s) of CBCT imaging? a. images can be saved digitally in a .jpg or .bmp format b. images can be placed on a compact disc c. images can be emailed to referring dentists d. all of the above

d. all of the above

the fact that the cone-beam data has a 1:1 relationship with the anatomy means that: a. anatomically accurate images are produced b. magnification of measurements does not occur c. CBCT eliminates the superimposition of structures d. all of the above

d. all of the above

When viewed together, the axial, coronal, and sagittal planes are referred to as ________________________________________.

multiplanar reconstructed images (MPR images)

In one single scan, the source of radiation and the digital sensor rotate around the patient and acquire __________ images of the FOV

multiple

prior to performing CBCT, what instructions should be given to the patient?

pts will be asked to remove all metallic items in the head and neck region, including jewelry, glasses, and removable dental appliances.

The radiation that passes through the patient and is received by the digital receptor is termed __________________

raw data

contrast resolution

refers to number of gray scales available

Choosing FOV and resolution depend on:

region of interest and reason for scan

True or False: A disadvantage of use of cone-beam data is that many dental professionals who incorporate CBCT into their practices have not had the training required to interpret anatomy beyond the maxilla and mandible.

true

Fundamentals of 3D imaging

■ Dental imaging is no longer limited to two dimensions. ■ 1999-CBCT (cone beam computed tomography) introduced. ■ Adoption of 3D imaging has expanded. ■ Provides accurate and detailed information. ■ Magnification, distortion, overlap of anatomy...minimize diagnostic quality of images. ■ 3D imaging provides more detail. ■ Comparable in size to panoramic machine.

What are some common used for 3D Imaging?

■ Implant placement ■ Extraction or exposure of impacted teeth ■ Definition of anatomic structures (mental nerve and inferior alveolar nerve) ■ Endodontic assessment́ ■ Airway and sinus analysis ■ Evaluation of TMJ Orthodontic evaluation ■ Evaluation of lesions and abnormalities ■ Trauma evaluation

Advantages of CBCT imaging

■ Lower radiation dose compared with traditional medical CT scan. -Comparable to 3-4 full mouth series of intraoral images. ■ Anatomically accurate structures. -Eliminates superimposition of structures. -Magnification of measurements does not occur - 1:1 ratio relationship ■ Ability to save and easily transport images

Disadvantages od CBCT Imaging

■ Motion artifacts occur when the patient moves. ■ Radiation is stopped and may not reach the receptor when it comes in contact with objects such as crown, bridge, large amalgam restorations). ■ If FOV is small, findings in other regions or the oral and maxillofacial area may be missed. ■ Cost of equipment and training. ■ Lack of training in interpretation of image data on areas outside of the maxilla and mandible.

CBCT Scan Procedure

■ Patient may sit or stand (depending on manufacturers guidelines. ■ Remove all metallic items in head and neck area ■ Sometimes an intraoral guide may be placed in the mouth ■ If referring specialists request, patient my be asked to keep teeth slightly apart (use cotton rolls, gauze square...) ■ Patient must remain still

spatial resolution

■ measurement, in mm, of the size of the pixels in the MRP images. ■ Also refers to the 3D pixels- voxels in the volume of data.

Name some of the common uses of three-dimensional imaging.

● implant placement-extraction or exposure of impacted teeth ● definition of anatomic structures ● endodontic assessment -airway and sinus analysis ● evaluation of the TMJ disorders ● orthodontic evaluation ● pathology evaluation