Veterinary Medical and CT – Part 2 – Is CT right for my veterinary practice?

Learning about CT and Cone Beam CT in veterinary medical applications.

Considering investing in a CT for your vet practice? Read this first.

You’ve probably already spoken to at least one sales person who has promised you the moon, and you’d like to trust that they have your best interests at heart. But how can you be sure that you’re investing in the right CT system that will help you round out your hospital’s imaging capabilities? You use ultrasound like a champ and your techs take fantastic digital radiographs. So…what about CT or Cone Beam CT? Purchasing one of these units is a lot more expensive than your ultrasound and your DR combined! You probably have more questions than a sales rep has good answers to.

What about asking a veterinary radiologist?

It is wise to seek good counsel from an experienced veterinary radiologist. I’ve talked to many veterinary radiologists about CT, and I’ve found two camps. The first is of the opinion that general practice veterinarians should avoid purchasing a CT, leaving specialty imaging to those who will “do it right” – which gets you high quality images that support accuracy of diagnosis. The second camp recommends CT as a good investment for a general practitioner. They believe that CT imaging in general practice, with proper staff training, continues the advancement of patient diagnostics at that level. In other words, a rising tide floats all boats.

Radiology Humor

A quick laugh about radiologists. A human radiologic technologist once told me that if you put 5 radiologists in a room and you will get 6 different opinions.

Investing in a CT scanner is no small decision

Before diving in, you must learn what CT is as a technology and what it is designed to be used for in veterinary applications. Not all CT machines are created equal in form and function. As stated in Part I of this blog, there are two types of CT technology available to veterinarians today, Spiral or Helical CT and Cone Beam CT.  This post goes into detail about the differences between Spiral or Helical CT and Cone Beam CT.

cone-vs-helical

What sales reps probably don’t know about Cone Beam CT (CBCT)

Why CBCT was developed

CBCT technology was originally developed for diagnostic applications in human dentistry for oral surgeons and dentists. These units are designed to produce high resolution cross-sectional exams of the human skull. The factory software in all CBCT machines can render the exam into a 3D model onscreen or into a more traditional stack of 2D images.

3D modeling from CBCT machines is useful in reconstructive surgery for dentists and surgeons in both human and veterinary medical applications. However, 3D images are of little diagnostic value to board certified veterinary radiologists. Radiologists always rely on the 2D image stack in cross-sectional imaging modalities to report their findings.

So manufacturers of CBCT took a technology originally developed for human dentistry and adapted it for the veterinary market.

Veterinary Medical Indications for Use of Cone Beam CT Technology:

Bone: skull fractures / nasal masses / dentistry / distal extremities / spine IVDD (requires contrast)

Soft Tissue: NO RECOMMENDED INDICATIONS ON MOST ANIMAL PATIENTS

The Science behind CBCT

CBCT emits a cone-shaped pattern of radiation, earning it the name “cone beam”. Essentially, a CBCT is a digital radiography system fitted onto a wheel inside of a gantry. It contains a small flat panel detector (usually about 18cm x 16cm) and it is positioned perpendicular to a cone beam x-ray tube (like the tube in a conventional x-ray system). As the wheel with the components is moved 1 degree a radiograph is taken, and then it advances another 1 degree and takes another and so on until it completes a full circuit around the animal patient.

Cone beam tubes produce a wide cone shaped signal pattern, originating at the tube (the point of the cone) and scattering outward toward the panel. This typically produces more scatter and less detail in the images when compared to spiral / helical CT modalities.

This is especially problematic in animals over 20 lbs., or in animals that are much larger than a human skull.

Can CBCT be a good tool for a veterinary hospital?

The hardware and software of CBCT units were optimized to acquire high resolution images of the human skull and particularly, the human mandible and maxillary portions of the skull. This means that it can definitely be a good tool for veterinarians who are passionate about canine and feline dentistry. Some veterinarians would be very interested in acquiring high resolution images of the patient’s skull which is crucial for quality performance of veterinary dental procedures such as extractions and reconstructive surgery.

The CBCT can also be used successfully for studies in the spine (IVDD with the use of proper positioning, collimation, and contrast). CBCT is also good when evaluating the integrity of joints and extremities (ex. canine elbow disease and osteosarcomas).

If the CBCT user can be trained to operate the technology within these limited indications, it can be diagnostically useful to a veterinary hospital, yet it will remain limited as compared to the spiral CT technology.

Some shortcomings of CBCT

CBCT units were not designed to perform scans of the thorax or abdomen on human or animal patients. The CBCT emits a cone shaped pattern which is cast upon the targeted anatomy. This results in more scatter radiation and less detail in the resulting images. This makes diagnosis more difficult because the images are not as clear.

Most CBCT manufacturers’ machines do not allow cranial to caudal movement of the patient. The table or couch does not move automatically. This means that operators need to move the table or move the patient if the targeted anatomy does not fit within the finite field of view.

Essentially, the CBCT unit remains stationary over the targeted anatomy and the field of view is limited to the finite dimensions of the selected capture area (L x W x D) in the acquisition software. This results in more than one series of images which will need to be either stitched together into a single stack of images or organized separately as individual image stacks with 1/3 or 1/2 of the targeted anatomy in one stack and the remaining anatomy in the subsequent stack(s). This can often frustrate a veterinary radiologist when reading a Cone Beam CT case that does not utilize automated and precise movement of the patient on the couch during the scanning process. When attempting to image the spine with CBCT, this can be a challenge for the operator to perform and for the radiologist to read.

CBCT scans can also take more time to complete. If the thorax / lung fields were to be the targeted anatomy; as animals breathe and the heart beats distortions are produced from the motion within the chest cavity during the scan. A manually induced breath-hold (while under full anesthesia), can reduce the effects of “motion artifact” from the lungs but the heart continues to beat so motion artifact remains problematic if the heart is what is targeted. In the animal patient, the most precise evaluation of the heart should be performed with ultrasound (i.e. an echocardiogram) and thoracic chest radiographs.

                 4 Slice CT Lungs                  CBCT Lungs

Note: the entire lung field is captured by the CT. The CBCT leaves out some of the lung field due to its confined field of view. Lung views in the CT image stack are much higher in resolution. In the CBCT image, there are too many artifacts, and in this case an incomplete field of view for a radiologist to read it successfully.

                  CBCT Abdomen      4 Slice CT Abdomen

Veterinary Radiologists and CBCT

In general, all boarded veterinary radiologists are familiar with spiral CT as it has been around in veterinary specialty clinics for a couple of decades. However, most, but not all veterinary radiologists have done no research on the cone beam CT technology. Therefore, most veterinary radiologists will have a negative opinion about cone beam CT simply because they know very little about it and how it’s meant to be properly used.

Radiation Safety

The CBCT folks claim their technology produces less exposure to radiation for patients and operators. They argue that lead-lined walls are not required. Depending on various state regulations, this claim may be true. The accuracy of such statements are at the mercy of the local regulations of the end user. In addition to that, we are simply comparing apples to oranges when comparing CBCT to CT. Remember, the core design of CBCT technology is limited in application to the skull or extremities. These anatomy indeed require less radiation for acquisition of diagnostic images. However, in reality, it is not much less radiation than what a spiral CT uses to acquire diagnostic images on the same anatomy.

In my opinion, it is always better to err on the side of safety. Go ahead and design your CT room with lead-lined sheetrock and place the acquisition workstation outside of the CT room behind a lead-infused glass barrier where your technologist can see the patient and the attending technician. Yes, this costs more money up front but it can save a practice from safety citations and lower the potential for employee / client litigation in the long run.

Can a veterinary hospital be successful with either technology?

The short answer is yes. The CBCT can be applied successfully in animal hospitals that perform a high volume of dentistry cases, and can be used effectively with imaging extremities as well as IVDD.

Conventional spiral CT technology can be even more successful because this technology can address more indications than their cone beam counter parts.

No matter which way you go, SUCCESS will hinge on whether or not the doctors and techs have the proper amount of comprehensive veterinary training for CT or CBCT.

shutterstock_211047973

Computed Tomography Training for Veterinary Teams

CBCT and CT are not easy modalities to add in a veterinary hospital environment. Floor plan and power are not the only challenges we face either. The proper amount of training and the proper types of training are what make CT the greatest challenge of all imaging modalities. Even ultrasound (which requires copious amounts of personnel training) is actually easier to integrate into a vet practice than CT is. The bummer is that most vendors who are selling CBCT and CT to veterinarians are doing minimal training with their buyers.

It is not a simple plug-and-play scenario. More than 60 hours of physics, safety, software / hardware operations, and veterinary applications training is required of veterinarians and their teams to make this technology successful.

Very few CT or CBCT vendors will offer a fully comprehensive program of computed tomography training for veterinarians or veterinary technicians. Many will only offer a “safety talk” and a few hours of software and machine operations training. So be advised that you are entering a venture where there veterinary CT training by most vendors is minimal and weak at best.

ANNOUNCEMENT: Dr. Holly Jarvis-Whitaker and the Instruction Intelligence adult education team will be launching a specialized CT and CBCT training for veterinary hospitals who own or plan to purchase a CBCT or CT. Please stay tuned to LinkedIn and the Veterinary Intelligence website  for updates on the launch of this highly advanced Veterinary CT training.

CBCT Summary:

PRO: Quality. Good image quality in canine and feline skulls as well as distal extremities.

PRO: Always sold brand new. Cost $175k – $250k depending on the vendor. 5-year warranty and service programs are offered with the purchase of CBCT from most vendors.

CON: Indications. Soft tissue image detail in the abdomen and thorax of animal patients is inferior to those generated by spiral CT. Some CBCT vendors advise the veterinarian to use ultrasound in lieu of their CBCT for abdominal soft tissue imaging. This is not bad advice, however, it is much easier to evaluate the size and precise location of masses / tumors with spiral CT.

CON: Field of View. A finite field of view on most CBCT machines can cause increased operator errors during acquisition. Most CBCT units do not move the patient or move through the patient cranial to caudal (automatically) which requires the manual movement of the patient by the operator and this produces multiple image stacks which each stack may only contain 1/3 or 1/2 of the targeted anatomy in larger canine patients.

CON: Training. Most vendors do not offer a comprehensive training program for vet techs and veterinarians. Most invest a few hours to teach the client basic operation with safety training after installation. This is problematic because the client is left to learn more valuable lessons by trial and error.

CON: Radiologist review and reporting. Most boarded veterinary radiologists will refuse to read and report on CBCT cases from veterinary hospitals. Only a select few are willing to read CBCT cases. VitalRads.com is one of the few veterinary teleradiology services that read veterinary Cone Beam CT exams.

What you need to know about Spiral CT (CT)

Spiral or helical computed tomography equipment is specifically designed for cross-sectional scans of soft tissue and bone in human patients. The CT couch or table slowly moves the patient through the spiraling signal. One newer CT design has a mobilized gantry that uses a motorized wheel system underneath to “crawl” over the table or couch where the patient is positioned.

An acquisition workstation and software render the acquired dataset and organize the data into one or more readable exams based on selected anatomy and protocol.

So this is also a technology that was adapted for veterinary from human medicine.

Veterinary Medical Indications for CT Scans

Soft Tissue: met checks / mass ID / lungs / liver / spleen / GI tract / urinary tract

Bone: skull fractures / nasal masses / dentistry / distal extremities / complete spine / hips / pelvis

The fundamental technology consists of a specially designed x-ray tube that emits a confined linear beam of photons which pass through the patient that is received by a linear array of sensors as the scanning unit it continuously spins around the patient at high speed.

What’s the deal with CT and the number of “slices”?

You may have overheard a conversation about CT where someone refers to the number of “slices” their particular CT has. This is because the higher the number of “slices”, the better the image quality. Ultimately, image quality in a CT is determined by the number of channels (aka slices) available in the sensor array. Please note that “slices” is a misnomer, because the number of slices really refers to the number of channels in the CT’s sensor array.

The more channels a CT sensor array has, the faster it can scan a patient, raw data acquisition also increases and then is processed into higher resolution images. The more raw data that acquired, the clearer the image quality. A 40 slice CT system can perform a full body scan on a 90 pound Labrador retriever in less than 15 seconds and still produce impeccable image quality. This occurs when the operator (aka technologist) is experienced and well-trained in applications and protocols for small animal veterinary medicine.

CT Software

Just like all software based technology, CT acquisition software applications have improved immensely over the last ten years. Most modern CT units (manufactured after 2010) will have highly-advanced acquisition software which allows a fully trained technologist to set up customized protocols which is great for applications in animal patients. CT units come from the factory with human presets (scanning protocols) in the software which means that it is up to the veterinarian and the CT technologist to adjust those protocols and customize their own presets for animal patients of various sizes and anatomy.

Some shortcomings of CT

They can cost a lot. Brand new CT units can easily cost a veterinary clinic well over $600k which is often more expensive than the real estate the vet hospital sits on. Purchasing a new or refurbished CT scanner can reduce the investment to below $250k for the equipment purchase. Then you need to add the extended service and warranty contracts after the first year is over.

There are older refurbished single slice CT machines available for sale that cost less than $80k (before you add facility modification, training costs, and extended service agreements). This is because a single slice CT is the slowest and lowest resolution model available. Single slice CT’s do a decent job imaging a patient, but they take longer (up to 20 minutes on that same 90 pound Labrador retriever which I mentioned earlier).

With lower resolution and slower scanning time comes a lower price tag, and vice versa.

Spiral CT machines are almost always purchased used or refurbished by veterinary hospitals. A brand new 64 slice CT will set you back at least $1 million. So, there is a delicate balance to be sought when looking to purchase CT. I intend to discuss pricing and ROI in part III of this blog which is forthcoming.

A good rule of thumb is to buy refurbished, buy a well-known brand (GE, Philips, Siemens, Toshiba), and stay between 4 and 16 slices. Another rule to live by; always purchase the preventive maintenance package with an extended warranty on the CT x-ray tube.

They are big. Most of the refurbished spiral CT units are huge by comparison to the brand new CBCT units. Spiral CT rooms need to be at least 16’x20’ when developing the room’s floor plan. All of the CBCT units I know of can exist in a 12’ x 12’ sized room.

Veterinary Radiologists and CT

In general, all boarded veterinary radiologists are familiar with spiral CT as they each were trained on how to read CT images from spiral CT units. You should have no problem finding a boarded radiologist to read your CT scans from a spiral CT.

If a vet hospital can maximize the use of a CT, it is a good investment to go with a spiral CT because it’s simply more versatile. Radiologists are more open to reading CT scans. They do take up more room but a spiral CT makes more sense for most general veterinary practices.

Can a veterinary hospital successfully use CT?

Absolutely yes. CT can be used successfully in animal hospitals who are looking to up their game on imaging and who want to raise the level of practice inside their clinic walls.

The long answer is a bit more complicated. Again, CT is not an easy technology to add to a veterinary hospital. It requires a different way of thinking on when and how imaging is ordered for animal patients. It requires much more training for veterinarians and technicians as compared to acquiring radiographs and/or performing an abdominal ultrasound.  This training differs among the spiral CT vendors but most training from these vendors is not veterinary focused which can be problematic.

CT Summary

PRO: Versatility. Spiral CT has a broader set of applications than CBCT.

PRO: Reads. All veterinary radiologists are trained and prepared to read CT studies.

PRO: Clarity: Spiral CT is faster, so the “motion artifact” problem is greatly reduced vs. CBCT

PRO: Easy: Spiral CTs come with pre-programmed protocols and can be manually programmed with protocols that your hospital uses frequently. This makes image capture faster and more consistent.

CON: Cost. Higher resolution means better, more diagnostic images, but it also means a higher price tag.

CON: Space. The room size for a spiral CT is greater than the space required for CBCT.

shutterstock_531887029

How does this information help my decision?

Decide what’s important to you! You want to improve your vet hospital’s ability to get great images. CT is a good way to go if you already have an active ultrasound modality and use your DR system to its fullest capacity.

If cost is a major consideration, you will want to consider how to start making your investment back as quickly as possible. That may mean getting some great training with experts in veterinary CT. Look for a full discussion about ROI on CT in an upcoming blog.

If space is a major consideration, that will play into your decision. If you are landlocked in a strip center or your imaging suite simply cannot expand beyond its current footprint, look carefully at the space required for each.

shutterstock_327440975

What is the culture in your veterinary practice?

Look at your culture and how you practice vet medicine. Maybe you don’t need a CT. You may not know if it will fit into your culture (i.e. your team’s collective philosophy of how you practice vet medicine). That is okay. It is imperative that you know your practice culture. There are two major cultures of thought in vet medicine and all others may vary minimally from one of these two.

1) There are veterinarians who enjoy the opportunity and ability to perform more specialty type levels of service such as CT and advanced orthopedic surgeries. This is in addition to doing basic wellness / internal medicine, and sterilization.

2) Veterinarians who prefer to be limited only to wellness, basic internal medicine, and sterilization surgeries. All of the advanced and more difficult cases are quickly referred down the road to a specialty hospital.

Do not kid yourself…if you are buying a CT to keep up with Dr. Jones down the road…maybe you should check if your clinical culture is prepared for such an advanced modality.

You are more than welcome to contact me privately or leave questions in the comments section. Please do not forget to check out these important resources on the web at VitalRadsInstruction Intelligence, and Veterinary Intelligence.

Thank you and have a great week! -RW

 

Veterinary Medical and CT: Part 1

It is officially Spring down here in South Texas. I have seen the first bloom of our bluebonnets today on my drive to and from Houston. They are beautiful! Western Veterinary Conference will begin next week in Las Vegas. There are new CT systems on display at the WVC trade show this year and I am pumped to see them and talk with the vendors. Computed Tomography is used in virtually all veterinary specialty hospitals in North America. CT machines have made their way onto the wish lists of many general veterinary practitioners. There are a few general practitioners who already own a CT. Maybe you are one who has begun to seek information on CT. If so, you have come to the right place!

shutterstock_76827394

I love veterinary technology and CT is at the top of my list. It is one of the most effective diagnostic tools in advanced veterinary imaging. I have become familiar with this modality over the last few years. Learning about CT seems easy at first but I must compare it to an iceberg. What you see on the surface is but only a small portion of what is needed for a veterinarian to make it successful. This is why I am writing a 3-part series on CT. One article cannot do this technology any justice.

This article will cover some of the basics. Part 2 will be released after WVC and will be highly detailed as I move through the different types of CT systems that are available to veterinarians. I will also outline the indications for veterinary use of the CT in more detail. Part 3 will cover the most critical nuances of CT technology such as contrast studies and the challenges that a general practice will have to meet head on when adding a technology that is advanced beyond anything purchased prior to ultrasound. Last but not least, I will share how to develop a return on investment for a CT.

The basic concept of modern computed tomography is based on x-ray technology with a spin…or shall I say…spins. Essentially, x-rays are used to acquire cross-sectional images of a specific region within a medical patient. CT machines have two halves. The couch (aka table) and the gantry (aka donut). The business end of the CT is all inside of that gantry. What makes one type of CT different from another really cannot be seen on the outside.

There are two types of CT scanners available for sale today.

SPIRAL / HELICAL CT          CONE BEAM CT (CBCT)

cone-vs-helical

The spiral CT machines are the most popular and widely used in human and veterinary medical facilities. I plan on diving into the differences between CT and CBCT in part 2.

As stated earlier, CT machines are being used in all specialty practices and vet schools but are becoming more popular with general practitioners. CT diagnostics include but are not limited to the following:

  1. Skull / Nasal / Brain
  2. C-Spine / T-Spine / Lumbar Spine
  3. Thorax / Met Checks / Masses
  4. Abdomen / Masses / GI Tract / Adrenals
  5. Hips / Pelvis / Extremities

Will CT reduce the need to use X-Ray and ultrasound?

No. It will not replace those modalities nor will it reduce your use of them. CT is often the next step in imaging diagnostics once an ultrasound and/or radiographs point to a more significant issue within the animal patient.

Clinical Scenario #1 

A two year old yellow lab presents with abdominal pain. An ultrasound is performed and the findings indicate that there is a mass in the abdomen. The size and exact location of the mass cannot be determined with accuracy. A CT will be ordered and the information it provides from the radiologist will indicate the following: 1) where the mass is 2) what it is attached to 3) exactly how large it is. From there a clinician can give the client more information about their pet and provide better options in treatment and prognosis.

Clinical Scenario #2

A 10 year old DSH feline presents for labored breathing, nasal discharge and lethargy. Radiographs of the thorax are normal. A quick view of the heart with the ultrasound reveals there is no pericardial effusion or cardiomegaly. A CT is performed on the skull of the kitty which indicates there is a mass in the nasal cavities and the mass penetrates into the bone. This is where CT provides an answer when ultrasound and x-ray could not. Could we have scoped the nasal cavities of the kitty? Certainly. However, sedation or anesthesia would have been required to do this and with a CT in the hospital, it is the easiest path to a definitive answer. Scopes are not in this case.

CT will add a new level of diagnostics to a practice. A veterinarian should not see a drop in the use of ultrasound nor will they use their x-ray system less.

Can I use CT instead of ultrasound or X-ray?

No. It is unethical, unnecessary, and expensive for our clients. CT machines are there for giving us a more complete answer when the ultrasound or the radiographs cannot give us a complete view of what is going on inside the animal. Moreover, even CT machines will have their limitations. Ultrasound is actually more suitable than CT for things like urinary tract infections and scans on other internal structures such as the heart. Furthermore, a CT scan requires anesthesia for the patient and the procedure itself will often cost two or three times as much as an ultrasound or radiographs. It is unwise to think you can replace an ultrasound or a digital x-ray with your CT. This is pure folly and certainly this should be obvious to any licensed veterinarian.

shutterstock_201780794

Is there special training required for adding a CT to my practice? 

Yes. There is special training required for all doctors and technicians working in that hospital. Operating the machine is the simplest part of this training and sadly that is mostly all one will get from a vendor. If you are planning on buying a CT for your practice, training will be the most important factor in whether or not the equipment will return the investment. In the specialty hospitals and the universities, CT technicians are sent to schools for few days at a time to learn the operations and protocols associated with performing CT studies on patients. Here is the tricky part; all of these “CT schools” are taught from a human medical perspective for human patients. Shameless plug alert! Instruction Intelligence is presently developing a formalized CT training program within the Veterinary Intelligence product line specifically for veterinarians and veterinary technicians. We will have a complete team of veterinary CT technologists and veterinary radiologists who will teach our clients all that they need to know about CT procedures that should be performed in a general veterinary practice. This program will launch in the Summer or Fall of 2017.

Do general practices in veterinary medical have any business whatsoever purchasing a CT machine? 

The answer to this question depends on several factors. 1. What is the culture of your veterinary practice? If your practice normally implements the best technology in imaging, labs, surgery, and treatments; then CT may be a good option. 2. Is your veterinary practice geographically isolated from veterinary referral centers? If so, adding a CT is definitely a good investment to consider. However, there are some general veterinary practices who are not isolated geographically and they have added CT with success. 3. Does your practice have frequent turnover of technicians and DVM associates? If so, CT would not be a good investment to consider because you obviously have larger problems to address in your hospital. The success of advanced procedures in any discipline of veterinary medical greatly depends on the attrition rate of team members such as technicians and associates. If a practice spends a great deal of time and money training new team members on a regular basis, CT (among other diagnostic tools) is not forgiving.

I will release part 2 of this blog at a later date and it may not be until late March 2017. Part 1 has been aimed at the most basic questions that I get asked when speaking with veterinarians who are looking into buying a CT. Please feel free to leave any questions in the comments and I will answer them as I have time to do so. Thank you for your valuable time and attention.

-RW