Understanding what ROI is really about

Dr. Brian Trava discusses his research before making a CBCT purchase

There are two acronyms of CBCT that are very different in their meaning, but correlate very well together in the real world. The diagnostician will tell you that ROI would be defined as Region of Interest. The businessman will tell you it would be Return on Investment. You really are investing in the capability to see detail. But if you don’t understand the details of your purchase, you may come up short in your investment and, most important, in your diagnosing.

Many practitioners do very little research before making a purchase, which leads to very little understanding both before and after the purchase. Having an underutilized CBCT taking up space is like an exercise bike at home with clothes hanging on it. In the decision making process, price should be at the bottom of the list. Multimodality and software capability should be at the top of your list. With the diversity of financing, Section 179 of the tax code, and added value to office resale, the long-term numbers are insignificant. If the machine you choose is not upgradable, or limiting, it may be no different than an old dental chair that costs you to dispose of. Evaluate your current practice needs, and make your decision based on your future needs.

Here is a really good tip before purchasing a CBCT machine for your practice. Artifacts influence clinical diagnosis and treatment. Detail gives higher patient acceptance and increased accuracy. When studying an ROI (Region of Interest), how does the software handle metal artifacts to provide detail and not distort it? You know, those nasty high-density objects such as amalgam fillings, PFM crowns, posts, and implants with high-attenuation coefficients that create all the streaks, starbursts, and dark shadows corrupting the imaging detail. Unavoidable, most all of your scans will be on patients with a wide range of dental work. Diagnosing is about detail; you are purchasing detail, and you expect detail to be delivered. Can your machine manage this? Without any compromise of detail?

So, when studying an ROI, how are artifacts handled within the field of view (FOV), and how is that related to detail? A CBCT machine can run an algorithm artifact removal program to reduce the streaks. But the actual metal object that is causing those streaks must be within the FOV for the artifact removal algorithm to work. In Figure 1, the image shows a small volume 5 cm x 5 cm FOV. An artifact removal was run, but streaks and interference are present. Why? Any metal objects that are outside the FOV volume, the artifact removal algorithm program has no effect on, and your region of interest (ROI) can be detail compromised (Figure 1). So, if you are looking for a fracture in a tooth in a small volume size, you need to consider what high-density objects are in the contralateral and surrounding teeth.

When considering and researching CBCT machines, our office made the decision on the Planmeca® ProMax® 3D for many reasons. With regard to FOV and artifact removal, the software platform is the most versatile. You have the option of a small FOV to a larger field of view of 8 cm x 8 cm if needed to capture within and process out high-density metal artifacts pending their proximity to your ROI. Next, the Planmeca ProMax 3D gave us the option to have a raw volume with no artifact removal or to run a scaled integrated amount of artifact removal depending on the quantity of high-density artifacts that may interfere with the ROI. These programs may be non-forgiving because they cannot distinguish between important and not important in the ROI. Endodontics is about detail. We did not want a CBCT machine that locked us into a standard artifact removal program that we had no control over. In Figure 2, no artifact removal program with an obvious fracture. In Figure 3, an artifact removal program was run showing a dilution of detail with regard to the fracture. In many patient cases we need that edge and prefer not to run any artifact removal.

As our practice grew, a second CBCT was needed. More companies and machines had entered the marketplace. When doing the research, again, versatility was an important factor. It was decided to add a second Planmeca ProMax 3D. Endodontics is about detail.

CBCT is really about detail, diagnosis, and treatment planning. Educate yourself before your purchase, recognize your needs in the future, become a better diagnostician, and your ROI (Return on Investment) will always be long-term.