Interpreting Advanced Imaging: It’s Best to Know Nothing

by John Khademi, D.D.S, M.S.

Interpreting advanced imaging, such as CBCT imaging, is tricky. Evidence of just how tricky becomes apparent during lectures I give on the subject. I will show a study to the audience and discuss it for several minutes. When I take it down, I ask them which side was buccal? Which side was palatal? Was it tooth number 14 or number 3?

The audience will start guessing, because they really don’t know—even after looking at the tooth for 5-10 minutes. They would never mistake buccal for palatal, or the tooth numbers, with 2D radiography. But with 3D radiography, it happens all too often. I’ve been evaluating 3D imaging everyday in my endodontic practice for eight years now, and I can still make this kind of mistake. The issue is this: we don’t have that same set of skills with 3D radiography that we do with 2D radiography, but we think we do.

In medical radiology, however, they’re well aware of the complexities that go along with interpreting imaging. That’s why medical radiology is a four-year specialty after medical school—with sub-specialties after that. You don’t want a mammographer evaluating the CT of your head or a thoracic radiologist reading your mammogram.

The need for specialization is clear: interpreting 3D imaging calls for a well-trained eye. That’s why we have to be very careful when we interpret with CBCT. For this reason, I’ve developed a strategy for interpreting 3D imaging based on what has been learning in medical radiology.

It’s important to note that I don’t automatically order an imaging on every patient. Whenever possible, my staff provides me with the minimum information necessary to determine if an advanced imaging study should be prescribed.  This very counter-intuitive finding is captured in the title of a 2002 paper in Radiology from noted radiologist Dr. Thorn Griscom: A Suggestion: Look at the Images First, Before you Read the History.”

Whenever possible, the preferred method involves doing two reads—first, without looking at the projection radiograph, doing a clinical exam or talking to the patient first about their symptoms or getting the history. My goal is to not have any preconceived notions about what the findings may be, let alone the diagnosis. Of course, with CBCT—especially with the focused field—if it’s an upper left side, I have a pretty good idea of where the problem is. But that’s all I really want to know.

I evaluate the study through that lens. I then get the history, look at the projection radiograph, review all the clinical information and perform the clinical exam. After that, I go back and look at the CBCT study again. This approach is very counterintuitive and not widely appreciated.  Current recommendations for approaching are as follows: conduct a thorough clinical exam and radiographic exam before prescribing imaging. In my opinion, that’s backwards, and not based on what has been learned about the interpretive process through careful research in medical radiology. Continue reading

CBCT at Its Best: Get Involved

Dr. Kunal Shah is the Principal of a new practice in Hendon, London – LeoDental. With a state-of-the-art CBCT installed, the practice is receiving referrals for implant planning cases. Completing his series of articles looking at the use and benefits of CBCT in implant treatment, Kunal explores where dentists can start when getting involved with implantology, highlighting the importance of mentorship.

Unlike other areas of dentistry, there is no clear path to follow when looking to get involved in implantology. It is often down to the individual to seek the appropriate training through courses and postgraduate qualifications that satisfy the GDC’s requirement for implant dentists to be competent in the field.

When looking for an initial training course, I would recommend asking the following questions in order to overcome some of the hurdles I faced:

  • What does the course entail? What do you gain at the end of it? – You need to establish whether you’re looking for a qualification or clinical experience, as this will determine what type of training you chose. The qualification courses tend to be the MScs and Diplomas, which are heavily theory-based, while others are more clinical and practical-based. I personally preferred the clinical element – as a dentist, you already have knowledge of the anatomy, so implantology is simply building on this. I also believe you need practical experience to develop your skills, learn from your mistakes and understand the different scenarios that can occur in practice. Continue reading

CBCT at Its Best: In Practice

Dr. Kunal Shah is the Principal of a brand new practice in Hendon, London – LeoDental. With a state-of-the-art CBCT installed, the practice is receiving referrals for implant planning cases. In the second instalment of his three-part series, Kunal demonstrates a clinical case study where CBCT scanning was integral for predictable treatment and the very best outcome for the patient.

Background

A female 52-year-old patient was referred to me from a local practice for implant surgery. I had developed a good rapport with the referring dentist, who was looking for mentorship through this case. The patient had had missing teeth for several years (15-20), although this had only recently begun affecting her lifestyle as she had issues eating – the problem was therefore functional rather than aesthetic.

The patient was fit and healthy, with no relevant medical background or allergies, a non-smoker, social drinker, moderate previous dental restorations and generally good oral hygiene. The LL6, LL7 and LR6 were missing, having been extracted many years ago. The adjacent teeth had started to drift and the opposing teeth on the other side were erupting.

The treatment options were discussed with the referring dentist and the patient, which included no treatment, bridges, dentures and implants. The patient wished to proceed with implants and consent was obtained. Continue reading

Five Things to Consider When Purchasing a CBCT System

The decision to add a CBCT system to your practice is a big one, largely because of the capital required. It isn’t like integrating a new laptop or tablet into your workflow. This kind of investment calls for careful consideration—particularly in five areas.

1.      Image resolution. The most important aspect of all: high image quality. Increasing your diagnostic capabilities is the number one reason to integrate CBCT technology into your practice in the first place. You need to be able to see your area of interest with unprecedented detail. But you also need to be able to adjust image quality with dose—so options for field of view are important.

2.      Versatility. What if you invest in CBCT imaging today and—six months down the road—you decide you want the ability to do cephalometric scanning? It would be nice to have a system that could expand with your capabilities, instead of having to purchase a whole new system. You should be able to take advantage of updates to your system when they become available, like for airway analysis, integration with CAD/CAM or low dose imaging. Continue reading

Atypical Anatomy: Tips on What to Look for in CBCT Data

While most of the scans you read will fall into the “normal anatomy” category, the logical next step in the journey of learning how to interpret data sets from cone beam computed tomography (CBCT) imaging is developing proficiency at deciphering anatomical variations. These variations can often be seen in intraoral and extraoral radiography, and it is sometimes helpful to use 3D radiography to fully understand certain variations; which otherwise could result in failure to diagnose.

One of the most common anatomical variations of a critical structure is the anterior extension/loop of the inferior alveolar nerve. Visualizing this structure is imperative when planning surgical procedures in the anatomical areas around mental foramen and the immediate area anterior to it.

Anterior extension of Inferior Alveolar canal: the red circle shows anterior extension and the yellow circle shows mental foramen

In addition to mental foramen, accessory foramen(s) can also be noted as a variation of normal anatomy in the mandible.

The temperomandibular joint (TMJ) area can exhibit wide variations in normal anatomy, which has to be correlated with clinical findings and additional imaging if necessary to establish the absence of any pathology. One of the most common variations can be the inter-articular space of the joint. This space may vary widely between contralateral joints of the same patient and between patients as well. The complexity of this anatomical region warrants a thorough review of all information available. Continue reading

Which Field Of View Is Right For You?

If you are wrestling with the idea of adding a new 3D imaging system to your practice, there are a few questions you should ask yourself:

  • What do I want to do with the information that the new system will provide?
  • Am I interested in return on investment (ROI)? (Of course you are, but is there more to it than that—like broadening your skills as a clinician?)
  • Am I expanding the capabilities of my practice in the future?

How you answer these questions can help you determine which field of view (FOV) is right for you and which imaging system best fits your needs.

What Do You Want to Do?
Is it endodontics? Implants? Airway analysis? Orthodontics? The following table can help you determine what to look for in an imaging solution.

Field of View
Small FOV
(5cm x 5cm)
Medium FOV
(8cm x 9cm)
Large FOV
(up to 17 cm)
Goal
Endodontics
View one or two teeth at a time
X X
Implantology
Scan single and dual jaw; perform guided surgery
 

X

X
Oral surgery
Evaluate: trauma cases; TMJ disorders; airway/sleep apnea disorders
X
Periodontics
(including, but not necessarily only implants)
 

X

 

X

Orthodontics
Evaluate: ectopic and impacted teeth; third molars
X X X
Assess TMJ, skeletal symmetry X
Airway
Evaluate airway, sleep apnea
X

 

Is Your Objective ROI?
If you are considering a shift to in-house imaging, ask yourself how many times per month you refer patients out for a scan. If your average is four or more, it may make sense to invest in a cone beam computed tomography (CBCT) imaging system. In about a year or less, your system could pay for itself.* Continue reading

The Top Five Reasons Why You Really Do Need CBCT

The decision to add a cone beam computed tomography (CBCT) system to your practice is a significant one—and one that can have far-reaching implications. It is a sizable investment, so the concern for obtaining a return on that investment is often top of mind. The ability to accurately evaluate anatomy in 3D requires training, which is another point to consider. Logistics, such as how the system will physically fit into your office space or the impact it will have on your workflow, are additional factors that you should carefully examine.

There are definitely many considerations to take into account when making a decision like this. But for many practitioners, the choice was an easy one, because the advantages of introducing CBCT to their practice were—and still are—very compelling. Here are the main reasons why.

  1. Improved diagnostic capabilities
    The impact that CBCT has on your ability to diagnose should not be understated. In fact, some practitioners believe they can’t practice without it. CBCT imaging provides a level of anatomical detail that enables practitioners to detect clinical situations like infections, lesions and hidden anatomy. The information that CBCT reveals (when superimpositions are removed) sometimes results in practitioners changing their initial diagnoses, because what is not visible with 2D imaging is often blatantly obvious with 3D imaging.

    With improved diagnostic capabilities, you can discontinue the practice of referring patients out for scans, which helps speed return on investment (ROI). You may decide to perform more procedures—or more complicated ones—yourself because the information revealed by CBCT imaging gives you the clinical confidence to do so, which also positively impacts ROI.

  2. Patient education and case acceptance
    CBCT imaging facilitates patients’ understanding of your treatment plans. Because patients can more easily visualize the area of interest in 3D than 2D, they are better informed about the diagnosis and feel more included in the diagnostic process. As a result, they are more likely to accept the treatment proposal. In addition, better education allays patient concerns, resulting in a more positive patient experience.
  3. Marketing
    New technology is a great differentiator, and the addition of CBCT to your practice provides you with the perfect opportunity to promote your capabilities. When technology-savvy patients are looking for doctors who are on the cutting edge of their profession, they may choose you over the practitioner around the corner who hasn’t added CBCT to his/her practice. For specialists, this technology can attract more referrals, too.
  4. Referral relationship
    As a general practitioner, it’s important to me to refer my patients to specialists who have the most up-to-date technology and who can provide the level of care my patients have come to know and expect. On the other hand, as an implant specialist, I know that doctors refer their patients to my practice because I am able to clearly visualize implant treatment and placement.

    In addition to increasing referrals, CBCT imaging enables you to more easily collaborate with referring doctors on your recommended treatment plans and final outcomes. Seeing is believing, and the ability to reference a CBCT image can greatly simplify what may otherwise seem like a very complex treatment plan. Referring doctors will likely feel more comfortable with your treatment choices and enjoy the ability to collaborate on treatment plan options through the virtual treatment plans in the 3D software.

  5. Workflow
    CBCT can enhance your workflow by keeping patients within the practice for imaging—eliminating the extra step of sending them out for a 3D scan. When patients go from initial appointment to 3D imaging to treatment planning—all in one appointment—the time savings is enormous.

    Not only that but, when chosen wisely, CBCT systems can streamline your workflow by working seamlessly with your imaging and practice management software. And, depending on the procedures performed in office, CBCT scans can also be merged with digital impressions from an intraoral scanner to improve implant planning, surgical guide fabrication and more.

If you’ve already incorporated CBCT into your practice, what are some additional benefits you have experienced as a result?

The Secret to Choosing the Right CBCT Unit [Video]

When it comes to cone beam computed tomography (CBCT) imaging systems, there’s a number of bells and whistles to choose from. In this video, Jordan Reiss, Carestream Dental’s North American Sales Director for 3D Imaging, provides his advice on how to choose the right unit to meet your practices needs.

Whether you’re currently in the market for a 3D unit, or you already have one, what do you consider to be the most important criteria for choosing a system?

Baby, You Can Drive My CBCT System

In the 1950s, America saw the beginning of “car culture,” and today there are roughly 210 million licensed drivers in the United States. Driving is almost second-nature. However, if you’re used to driving a Volvo and I give you the keys to a Mercedes, it may take a moment or two of adjustments before you’re ready to cruise down the highway. It’s not because you don’t know how to drive; it’s just a matter of learning a new system.

A cone beam computed tomography (CBCT) system is not unlike becoming comfortable with a different make and model of car. I’ve been operating my system for years now, and can comfortably “turn on a dime” or “shift gears.” However, when I invite a referring doctor to “go for a drive,” e.g., share the 3D imaging software for collaborative cases or email a screenshot of a scan, there may be a bit of a learning curve. But once the general practitioner learns to properly view the scans, it not only helps me build stronger relationships with them, but allows for me to gain greater future referrals.

resportion-incisorFirst, CBCT allows me to view a patient’s anatomy in stunning 3D detail, and can reveal much more than what a traditional panoramic X-ray could. I share these CBCT scans with the referring doctor and usually get one of two responses—“Yes, good, proceed with treatment,” or “Your system showed you all that?! Tell me more…” Of course, it’s perfectly acceptable for the referring doctor to trust my judgment and go with my proposed treatment. However, there’s something to be said about the GP who wants to gain a better understanding of the CBCT findings.  Also, greater communication, increases the chances that future treatment will have less hurdles.

So if that’s the case, I take the time to meet with the general practitioner in person to go over the scan in more detail. For example, a CBCT can elucidate a proposed implant site with a buccal-lingual cross cross-sections for both horizontal measurements and for visualizing the distance from the crestal bone to the nerve canal.  My 3D imaging software is also easy to share, which gives the GP a bit more freedom to play around in the scan and take the CBCT for a “test drive.” Continue reading

Human Evolution or a Technological Revolution?

In the 1960s, root canal morphology was looked at differently than today. The common thought was that molars generally had three canals. Today, we know that there are often four, sometimes five canals. Have humans genetically evolved in the past 50 years? No. But new technology, such as cone beam computed tomography (CBCT), reveals minute details of root morphology like never before.

Essentially, CBCT allows us to miss less of what we did in the past by giving us high-resolution, three-dimensional scans of patient anatomy. Focused fields of view mean endodontists can review highly detailed images with up to 75 μm resolution (0.075 mm slices). Plus, when the doctor is able to see the root of the problem, it means a more comprehensive, and therefore successful, treatment plan and often times less post-operative pain for the patient.

Technology has changed dramatically over the past decades to allow us to diagnosis and treat patients in a way never thought possible. My partner recently retired, and in over 50 years, he rarely ever saw a tooth with five canals; whereas, my CBCT system has revealed dozens of cases with five canals. It’s just an amazing example of how CBCT is changing the way endodontists practice. Who knows what revolutionary technology will reveal next?