cbct- good, bad, and sometimes…ugly!_bad,_and_sometim.pdftraditional ct uses a very narrow, fan...

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CBCT: Good, Bad, and Sometimes…Ugly!:

Presented by: Juan F. Yepes DDS, MD, MPH, MS, DrPHProfessor of Pediatric DentistryDepartment of Pediatric DentistryIndiana University School of DentistryAttending, Riley Children HospitalIndianapolis, [email protected]

Disclosure Statement

Juan F Yepes DDS, MD, MPH, MS, DrPH

I have no relevant financial relationships to disclose.

Learning

objectiv

es 1. Understand the basic principles of CBCTAND the main differences with CT

2. Discuss the importance of the interpretation in the context of CBCT

3. Learn the potential application (and be critical) of the use CBCT

4. Understand the LIMITATIONS of CBCT technology

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CBCT: Good (meaning), Bad (meaning), and Sometimes…Ugly (meaning)!:

CBCT in the last 20 years

•Introduction•Basic principles•Radiation safety•Systems available in the market•Performing and interpreting diagnostic CBCT•Third party software•Final remarks

Gen

eral Overview

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Patient history

Physical Exam Radiology

Diagnosis

Laboratory

Consults

The basics…….

Limitations of Two‐Dimensional X‐rays

2D images can give an incomplete picture..

With the X‐ray source in this position

We see that the figure is holding a banana (we cannot see that she is also holding a pineapple)

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28 y.o, male, pain over the right maxillary sinus for 6 months. Several treatments without improvement

Pano

ramic Film

CT, bone window, axial planePanoramic film

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CT, soft tissue window, axial plane

Basic Principles

Key Points

The use of CBCT imaging in the dental profession has blossomedsince the inception 15 years ago. CBCT unit design has undergonemany changes that enhance CBCT access and utility in dentistry

Smaller scanners, patients in an upright position, and flat paneldetectors

CBCT manufactures have incorporated various aspects of imagingtechnology in a cost‐effective, efficient, and practical manner

Beam hardening imaging artifact that compromises CBCT utility

Basic Principles

Backgrou

nd Image is accomplished by using a rotating gantry to which an x‐ray sourceand detector are fixed

A cone‐shaped source of ionizing radiation is directly through the middleof the area of interest onto an area x‐ray detector on the opposite side

During the rotation, multiple (from 150 to more than 600) sequentialplanar projections images of the field of view (FOV) are acquired

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Basic Principles

CBCT vs. Computed Tomography

CBCT is a form of computed tomography (CT). In a single rotation, the region of interest(ROI) is scanned by a cone‐shaped x‐ray beam around the vertical axis of the patient head

Digitized information of objects in the ROI (shape and density) is acquired in multipleangles

These imaging data are then processed by specialty software that reconstructs the imagein multiple planes.

X‐ray

Detector

Signal

Digitize

Analyzed by a mathematicalalgorithm Reconstructed

Computer Tomography

X‐ray Detector

Digitize

Analyzed by a mathematicalalgorithm Reconstructed

Computer Tom

ography

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Computed Tomography (CT)

Traditional CT uses a very narrow, fan beam that rotates around the patient acquiring one thin slice (image) with each revolution

To image a section of anatomy, many rotations must be completed—which means higher radiation exposure

With Cone Beam Computed Tomography, the entire volume is acquired in a single pass around the patient…

Resulting in much less radiation exposure!

Cone Beam Computer Tomography (CBCT)

Basic PrinciplesImage Sensor Systems

CCD with a fiber‐optic image intensifier

Amorphous silicon flat‐panel detector

Larger dimensions of the scanner More susceptible to distortionMore frequent calibrationPhosphorus lose sensitivity over time

Smaller, less bulkyThe scintillator is part of the detectorMinimal distortionSmaller footprints

www.lambertinstruments.com

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Basic Principles

Active Area

Pixel size

Small

Small

Larger

Larger



Image Sensor System

s

Basic Principles

Image Sensor Systems



Image Sensor Systems



Image quality

Higher signal‐to‐noise ratio(means = better contrast)

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Basic Principles

Effect of Field of View on Scanner Type

The size of the scanned object volume is called the field of view (FOV)

The FOV for units with a flat‐panel detector is a cylindrical shape

The FOV is a very flexible option for contemporary units

The FOV for flat‐panel detectors range from 3.0 cm (H) x 3cm (D) to 24 cm (H) x 16.5 (D)

Basic Principles


Heigh

t

Flat‐pan

el detectors

Basic Principles


The FOV for image‐intensifying detectors is shaped differently, not as cylinder butrather as a sphere.

The dimensions are usually measured by the diameter of the circular shape in inches

The size of the FOV significantly affected the evolution of CBCT scanner.

Early CBCT units were restricted to a single‐size FOV that was either large or small

General rule larger the FOV, the greater the cost of the scanner (large detector size)

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Basic Principles


Larger FOV not popular for limited dento‐alveolar applications

Contemporary CBCT units small, midrange, large FOVs

Basic Principles

Scanners with large field of view (FOV)

Model Manufacturer FOV Voxel Notes3D Accuitomo JP Morita 12 x 17 0.08 ‐3D eXam Kavo 17 x 23 0.125 ‐CS 9300 Carestream 13.5 x 17 0.09 Previously KodakDaVinci Cefla 15 x 15 0.17 Supine positionGalileos Sirona Sphere 15.4 cm 0.125 Image intensifieri‐CAT Imaging Sciences 17 x 23 0.125 QuickScan®NewTom QR 16 x 18 0.075 Supine position

Basic Principles

Scanners with large field of view (FOV)

Model Manufacturer FOV Voxel NotesProMax 3D Max Planmeca 17 x 22 0.08 ‐ProMax 3D Mid Planmeca 17 x 20 0.1 Can obtain a stitched 26 x 23Scanora 3D Sorodex 13 x 14.5 0.133 ‐Scanora 3Dx Sorodex 24 x 16.5 0.10 Supine positionSkyview MyRay Sphere 22.9 0.17 Supine position

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Basic Principles

Scanners with medium and small field of view (FOV)Model Manufacturer FOV Voxel Notes

AUGE ZIO Asahi 8 x 10 0.1 ‐Cranex 3D Sorodex 6 x 8 0.085 ‐CS 9000 3D Carestream 3.75 x 5 stitched 7.5 x 3.75 0.076 (0.2) ‐GXCB 500 Gendex 8 x 14 0.125 Powered by i‐CATGXCB‐500 HD Gendex 8 x 14 0.125 Powered by i‐CATi‐CAT Precise Imaging Sciences 8 x 14 0.125OP‐300 Instrumentarium 6 x 8 0.085PreXion 3D Eclipse Prexion 8 x 11 0.15

Basic Principles

Scatter and Beam‐Hardening ArtifactScatter and beam‐hardening artifact occurs in CBCT imaging

Dense metal structures frequently in the FOV for dental applications present metal artifacton CBCT reconstructions

Silver amalgam, metal alloys, dental implants, silver point endodontic fillings all createthese artifacts in imaging reconstructions

The main types of beam‐hardening are the dark streaks or dark bands “caries” or “fractures”

Basic Principles

Scatter and Beam‐Hardening Artifact

Degrade image quality

Compromise anatomical landmarks

Recent attempts software corrections, however…

The best way to avoid these issues keep the FOV assmall as possible in an attempt to minimize or keep these metals outside the FOV

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Radiation Safety

CBCT 1 day?

Sources ofRadiation Exposure

Natural

Artificial

3.5 mSv / year

83% (3mSv / year)

17% (0.6mSv / year)

Cosmic

Terrestrial

Internal

radonIngestionof food

2.4 mSv

Radiation Biolog

y

http://www.ans.org/pi/resources/dosechart/msv.php

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Justification for ImagingProfessional Guidelines for use of radiation in dentistry ( 2012 ADA Council of Scientific Affairs)

• This recommendations are subject to clinical judgment and may not apply to every patient.

• They are to be used by dentist ONLY after reviewing the patient’s health history and completing a clinical examination

• Even though radiation exposure for dental radiographs is low, once a decision to obtainradiographs is made, it is the dentist responsibility to follow the ALARA principle tominimize radiation exposure

Effective Do

se from

Diagn

ostic

Radiolog

y an

d eq

uivalent backgroun

d

Examination Effective Dose (mSv)

Equivalent background

radiation (days)

Extraoral

PanoramicCephalometric

0.006‐0.0260.002‐0.066

1‐30.5‐1

CBCT I‐CAT® (extended view: 16 x 13 cm) 10 y.o.

0.134 13

CBCT Accuitomo® 170 (small view:

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Pediatric Phantom Dosimetry of Kodak 9000 CBCTYepes JF, Booe M, Sanders B, Jones J, Eckert G

Radiation Safety


Panoramic film 0.026(mSv)

CBCT Mandible

0.065(mSv)

CBCT Maxilla 0.053(mSv)


CBCT Maxilla(Salivary glands) 1.8 (mSv)

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CBCT systems available in the market(always a partial list)

Model Type Manufacturer Position Voxels3D Accuitomo CBCT J Morita Sitting 0.1253D Accuitomo FDP 170 CBCT J Morita Sitting 0.08, 0.125, 0.1603D Accuitomo FDP 60 CBCT J Morita Sitting 0.125Art 3D Pano‐CBCT‐

CephOy, Espoo Stand NA

CB MercuRay CBCT Hitachi Sitting 0.1 to 0.4CB Throne CBCT Hitachi Sitting 0.1 to 0.4Digi‐X‐3D Pano‐CBCT Oy Ajat Stand NAGalileos Comfort CBCT Sirona Sitting / stand 0.15‐0.30Galileos Compact CBCT Sirona Sitting / stand 0.15

CBCT machines available in the market (always a limited list)

Model Type Manufacturer Position VoxelsGX‐CB 500 CBCT Gendex Sitting 0.125 – 0.4I‐CAT Classic CBCT Imaging Sciences Sitting 0.2‐0.4I‐CAT Next Generation CBCT Imaging Sciences Sitting 0.125‐0.4Illuma LFOV CBCT 3M Sitting 0.09, 0.2, 0.3, 0.4Illuma SFOV CBCT 3M Sitting 0.09, 0.2, 0.3, 0.4Kavo 3D Exam CBCT Gendex / Kavo Sitting 0.125‐0.4Kodak 9000 3D Pano‐CBCT Carestream Stand 0.076Kodak 9500 LFOV CBCT Carestream Stand 0.2‐0.3Kodak 9500 MFOV CBCT Carestream Stand 0.2‐0.3


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Model Type Manufacturer Position VoxelsNewTom 3G CBCT Quantitative

RadiologySupine 0.16‐0.42

NewTom 9000 CBCT QuantitativeRadiology

Supine 0.29

NewTom Vgi CBCT (mobile) QuantitativeRadiology

Stand 0.15, 0.24, 0.3

OP3000 CBCT Instrumentarium Sitting NAOrion CBCT Ritter Imaging Sitting 0.111, 0.167PaX‐500 ECT Pano‐CBCT Vatech Stand 0.186‐10PaX‐Uni 3D (OS) Pano‐CBCT‐Ceph Vatech Stand 0.08‐0.125Picasso Master 3D CBCT Vatech Sitting 0.164Picasso Trio Pano‐CBCT‐Ceph Vatech Stand 0.2‐0.3


Model Type Manufacturer Position VoxelsPreXion 3D CBCT PreXion Sitting 0.1‐0.15ProMax 3D CBCT (Ceph

optional)Planmeca Stand 0.1‐0.2

ProMax 3D Max CBCT Planmeca Stand 0.1, 0.2, 0.4PSR 9000N CBCT Asahi Sitting 0.1‐0.15Scanora 3D CBCT Sorodex Sitting 0.12‐0.35Scanora 3D with Pano Pano‐CBCT Sorodex Sitting 0.13‐0.35Skyview CBCT MyRay Supine 0.16,0.23, 0.33Veraview 3D Pano‐CBCT‐Ceph J Morita Stand 0.125‐0.2


Performing and interpreting

diagnostic CBCT

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Liabilities and Risk of Using CBCT

The use of CBCT carries with it medicolegal risk which the practitionershould be aware

A practitioner who intends to take and / or use CBCT scans should seekadvise from his malpractice carries before doing so

All the scans should be read by someone competent to interpret them

Using the services of an out‐of‐state radiologist to read scans poses its ownset of risk

Key Points


To scan or not to scan: The standard of care

Unlike medications that must be approved by the FDA for specific indications before they can be put on the market, the same is not TRUE of devices such as CBCT

For new techniques and technologies for which there are not “standard of care”, the issueof WHEN AND HOW to use then can be quite problematic for clinicians

Dental boards may create standards of care through their regulations (Oregon for example)

In practice, the use of CBCT may be driven in part by vendors of the equipment


To scan or not to scan: The standard of care

At the present time (August 2020), it can be stated that the use of CBCT is well‐acceptedin implant planning and endodontics (Positions papers published)

The use of CBCT is also well accepted to evaluate impact teeth, complex orthodontic andorthognathic cases (patients with syndromes for example)

Unfortunately, “fear of malpractice” motivation in some situations to order a CBCT

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Technical Parameters

Proper technical parameters are important to obtain a clinically acceptable scan

Improper technical parameters may lead to liability:

low resolution setting (0.3 mm voxel or higher) (higher number : lower resolution) inappropriate FOV (one one hand, FOV as small as possible to limit the amount of

radiation and to improve the resolution, on the other hand FOV should include a sufficient view of the anatomical area)


Interpreting CBCT Images (I)

The interpretation of CBCT images remains one of the most frustrating problems forpractitioners who take their own scans, and potentially among their greatest sources ofliability

Although malignancies are rare compared with typical dental pathology, so that the risk ofencountering one and not diagnosing it is small, if the risk does materialize consequencesfor the patient

Among dental school faculty, there is currently a debate on whether to teach dental studentsto interpret CBCT scans


Interpreting CBCT Images (II)

Interpretation courses offered by the AAOMR and the ADA

Dentist who take their own scans are responsible for reading them

Dentist who take their own scans can refer to a radiologist to read them

Dentist who use a scan center “reading service” by a radiologist

If a dentist owns and/or operates a CBCT machine and takes a scan for a patient other than hisor her own, the question arises whether the dentist taking the scan is responsible for reading it or whether is the responsibility of the referring dentist

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What needs to be read

Whoever reads the scan is responsible for reading all of it, NOT ONLY the anatomical regionfor which the scan was taken

This standard is not different from that for any other image taken

Given the fact that the images can be sent over the internet and be read anywhere, it has become commonplace for practitioners to have scans read by radiologist who do not reside inthe same state as the dentist QUESTION: where must the radiologist be licensed, in the statewhere the dentist practices, in the state where the radiologist practices or BOTH?

Potential issue of ”negligent referral”


What needs to be read

Whoever reads the scan is responsible for reading all of it, NOT ONLY the anatomical regionfor which the scan was taken

This standard is not different from that for any other image taken

Given the fact that the images can be sent over the internet and be read anywhere, it has become commonplace for practitioners to have scans read by radiologist who do not reside inthe same state as the dentist QUESTION: where must the radiologist be licensed, in the statewhere the dentist practices, in the state where the radiologist practices or BOTH?

Potential issue of ”negligent referral”


Attempts to limit liability

Asking patient to sign a waiver of liability (no legal effects and courts will ignore them)

Different approach: letting the patient choose whether to have the scan read (limited by thebounds of accepted standard of care

Some health care practitioners and organizations are using contracts to limit at least thenon‐economical damages that a patient may recover

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tumor

3 party software available to use with CBCT

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Basic Principles

Third‐party software available for imaging CBCT data setsSoftware Manufacturer Uses

CS 3D Carestream Multiple applicationsDolphin 3D Dolphin imaging Multiple applicationsEasy Guide Keystone Dental Implant planningIn Vivo Dental Anatomage Multiple applicationsOn demand 3D Cybermed Inc Multiple applicationsOsiriX Pixmeo Multiple applicationsProcera Nobel Biocare Implant planningUltrafast CBCT Bronnikov Multiple applications

Orthodontics

Image courtesy of Dr. Alan Farman, University of Louisville SOD


Orthodontics – OMFS – Dolor Orofacial

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Orthodontics – Pediatric Dentistry ‐ OMFS

CBCT in REAL LIFE

3D Imagining in Dentistry: Potential risks and diagnostic opportunities

We take for granted that volumetric imaging provide us with more information, but……

There is at this point little evidence for improved diagnostic efficacyover alternative radiographic examinations.

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Clinical Recommendations Regarding Use of CBCT in OrthodonticsPosition statement by the AAOMR

Oral Surg Oral Med Oral Pathol Oral Radiol 2013; 116:238‐257

“…there is not clear evidence to support the routine use of ionizing radiation instandard orthodontic diagnosis and treatment planning including the use of CBCT”

Evaluate right canine (12 y.o)

14 year old, evaluate radiopacity lower left side

Oral Pathology

Radiopacity lower left

Sagittal

Axial

Coronal

Evaluate disto‐dens (10 y.o)

Reformatted panoramic film

Oral Surgery

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Evaluate disto‐dens

Evaluate right canine (12 y.o)

Oral Pathology

Evaluate delayed eruption

9 year old, evaluate damage over the lateral incisor

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Evidence Supporting the Use of CBCT in Orthodontics

Systematic review of CBCT applications in orthodonticsand evaluated the level of evidence the determine whether the use of CBCT is justified in orthodontics

The authors found NO high‐quality evidence regardingthe benefits of CBCT in orthodontics.

Limited evidence shows that CBCT offer better diagnosticpotential, lead to better treatment planning or results inbetter treatment outcomes than do conventionalimaging modalities

Evidence Supporting the Use of CBCT in Orthodontics

Systematic review of CBCT applications in orthodonticsand evaluated the level of evidence the determine whether the use of CBCT is justified in orthodontics

The authors found NO high‐quality evidence regardingthe benefits of CBCT in orthodontics.

Limited evidence shows that CBCT offer better diagnosticpotential, lead to better treatment planning or results inbetter treatment outcomes than do conventionalimaging modalities

OMFS

Final Remarks

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Final remarks on the use of CBCT

CBCT examinations must not be carries out unless a history and clinical examination haveperformed

CBCT examinations must be justified for each patient to demonstrate that the benefits outweigh the risk

CBCT examinations should potentially add new information to aid the patient’s management

CBCT should not be repeated “routinely” on a patient without a new risk/benefit assessmenthaving been performed

CBCT should only be used when the question for which imaging is required cannot be answeredadequately by lower dose conventional radiography

Final Remarks on the use of CBCT in pediatric dentistry

CBCT images must undergo a thorough clinical evaluation (Radiology Report) of the entireimage dataset

When is likely that evaluation of soft tissues will be required as part of the patient’s radiologicalassessment, the appropriate imaging should be conventional CT or MRI rather than CBCT

CBCT equipment should offer a choice of volume sizes and examination must use the smallestthat is compatible with the clinical situation if this provides less radiation dose to the patient.

A quality assurance program must be established and implemented for each CBCT facility,including equipment, techniques and quality procedures

Final Remarks on the use of CBCT in pediatric dentistry

CBCT equipment should undergo regular routine test to ensure that radiation protection, for both practice /facility users and patients, has not significantly deteriorated

All those involved with CBCT must have received adequate training for the purpose ofradiological practices and relevant competence in radiation protection

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Future of the CBCT• Implications of a large FOV (paranasal sinuses, middle ear, brain, cervical spine, and soft tissues of the neck).

• Referral to an Oral and maxillofacial Radiologist (few, considerations ofsending the images electronically between different states)

• HYBRID CBCT: combines digital panoramic radiography with small FOV

• Hybrid CBCT: less expensive than traditional CBCT, smaller data size andhigher resolution voxel size (as low as 0.1mm)

• Third‐party software to put together several images

Resources/References

• Radiation Protection in Dentistry Report 177, National Commission for Radiation Protection 2019

• Oral Radiology: Principles and Interpretation. Mallya & Lam, 8thedition 2015

Questions

Juan F Yepes DDS, MD, MPH, MS, DrPHProfessor of Pediatric DentistryDepartment of Pediatric DentistryIndiana University School of [email protected] Instagram

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cbct- good, bad, and sometimes…ugly!_bad,_and_sometim.pdftraditional ct uses a very narrow, fan...

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