The Hospital for Special Surgery (HSS) located in Manhattan is ranked as the #1 hospital for orthopedics by the prestigious US News and World Report (2016-2017). And when the surgeons and clinicians at this elite medical institution need to make a proper foot and ankle diagnosis, they rely on CurveBeam’s revolutionary pedCAT system for fast and accurate 3D imaging.
Assessing the root cause of a patient’s pain is essential for developing a comprehensive treatment plan. At HSS, this evaluation process begins with an interview so that specialists can learn a patient’s unique history and obtain information regarding the primary care physician’s prognosis. Then the patient steps into the pedCAT scanner, where expert radiologists can conduct foot and ankle imaging faster than X-rays and CT scans, resulting in fewer hospital trips and significantly reduced exposure to radiation. The pedCAT system delivers the highest quality images and robust data, allowing physicians to make the most accurate diagnosis of the malady, and guiding the surgeon in the operating room for a superior treatment outcome. Watch below and visit curvebeam.com to learn more about the pedCAT.
Three-dimensional weight-bearing computed tomography (CT) can be a powerful diagnostic tool, typically used when more information is necessary (e.g. intra-articular fractures, occult fractures and small bone tumors). Unlike conventional CT, which has a fan-shaped X-ray beam, modalities in the pedCAT created by CurveBeam have a cone-shaped X-ray beam. In a Podiatry Today’s article titled “Current Concepts With Weight bearing CT”, Dr. Albert V. Armstrong Jr., dean of the Barry University School of Podiatric Medicine, reviewed three independent studies that examined the efficacy of the technology.
In the first, Yoshioka and colleagues studied 10 patients with posterior tibial tendon dysfunction and 10 control patients, using weight-bearing and non-weight-bearing CT.1 The authors noted that the study clarified part of the clinical condition of the forefoot in flatfoot deformity, saying this may be applicable in basic research of the staging advancement and sub-stage classification of flatfoot.
In the second study, Krähenbühl and coworkers used weightbearing CT to determine the subtalar vertical angle in a study of 40 patients with osteoarthritis and 20 control patients.2 The study authors found that measuring the subtalar vertical angle was a reliable and consistent method to assess the varus/valgus configuration of the posterior facet of the subtalar joint.
In the final study, Geng and colleagues studied weightbearing and non-weightbearing CT scans of 10 patients with hallux valgus and 10 control patients, reconstructing 3D models for the first metatarsal and the medial cuneiform.3 Researchers noted the study furthers an understanding of the physiological and pathological mobility of the first metatarsocuneiform joint.
Weightbearing CT is a safe imaging modality with low radiation exposure that can provide superior images in comparison to conventional CT, as evidenced by the multiple studies. Weightbearing CT can enhance biomechanical evaluation, preoperative planning, postoperative evaluation, wound management, sports medicine, treatment of arthritic conditions (especially degenerative joint disease) and trauma (especially when looking for occult or hairline fractures). It is a promising and up and coming imaging method to replace traditional CT technology.
Cone beam CT allows clinicians to obtain an image of a volume of tissue in one circumferential pass instead of having to take multiple slices with multiple exposures. This leads directly to reduced radiation exposure for patients. Studies indicate, in the example of a bilateral scan of a foot, the pedCAT machine exposes patients to one third the amount of radiation as traditional methods. Another great feature of weight-bearing CT is the ability to perform bilateral scans. One can also view the same patient with the view of the the soft tissue structures removed, leading to increasingly accurate prognosis. In addition, the pedCAT is an excellent tool to illustrate visually to a patient exactly where a bunion, for example, is located underneath the soft tissue. The generated visual displays are much easier to understand for non-trained individuals.
Performing actual weightbearing examinations is possible through pedCAT, a main advantage of the machine. In a specific instance, a podiatrist can view a foot supporting weight, viewing the 3D image and the accompanying 2D images in the sagittal, axial (transverse) and coronal (frontal) planes. This would allow the physician to observe the appendage in its most natural state, allowing a more precise diagnosis of problems.
Ballet is an art of extremes. As such, the risk factors are high among dancers for developing chronic injury and weakened tissues throughout the lower half of their bodies. About 60% of ballet injuries affect the legs, hips, ankles or feet. Lateral ankle sprains and Posterior Ankle Impingement Syndrome, or the pinching sensation felt during repeated floor or barre work as the heel bone comes into contact with the talus bone, are chief among them.
By the age of 12, ballet dancers are generally considered ready to begin learning the en pointe technique which utilizes the unnatural convergence of the tibia, talus, and calcaneus to lock the ankles in place.
While we do know this position may facilitate injury, prior to the advent of advanced CT imaging podiatrists had no method of accurately determining the exact anatomical position of either bones or tissue in this position.
CurveBeam, founded in 2009, designs and manufactures Cone Beam CT imaging equipment for the orthopedic and podiatric specialties. In 2012 CurveBeam’s pedCAT system received official clearance from the FDA, and in 2013, CE Mark approval. With the implementation of tools such as the pedCAT and CubeVue, CurveBeam’s custom visualization software, researchers finally have the capability to help ballet teachers better understand the demands of this position before introducing it to young students.
Pointe technique, when examined through an advanced imaging system, reveals the posterior portion of the talus resides beyond its articular surface, while the posterior portion of the tibia’s articular surface leaves the articular surface of the dome to rest on the posterior talus. The three bones converge. According to Dr. Jeffrey A. Russell, Ph.D, A.T., FIADMS:
“Attaining the full en pointe position requires contributions from movements between the bones in the foot. Examples of such movements include sliding between the talus and the navicular, the navicular and the medial cuneiform, and the medial cuneiform and the first metatarsal. These small increments of motion combine to provide approximately 30% of the plantar flexion range.”
“In addition, it is noteworthy that the talus shifts slightly anterior from under the tibia as the ankle-foot complex moves en pointe. This subtlety arises because the converging tibia, talus, and calcaneus form a fulcrum that applies an anterior force to the talus, somewhat like a watermelon seed being squeezed from between one’s thumb and forefinger.”
Recently, Dr. Russell took to an advanced open MR scanner to review the upright and weight bearing position of uninjured ankles in six university-level dancers who had been dancing for an average of 13 years, and dancing en pointe for an average of seven years.
“All exhibited several traits in their ankle MRIs: the posterior portion of the articular surface of the tibia rested on a nonarticular surface of the posterior talus; the synovial sheaths of the flexor and fibularis tendons collected fluid; Kager’s fat pad was impinged by the posterior tibial plafond; and small ganglion cysts were apparent in one or more spots around the ankle and proximal foot.”
It’s an interesting find, and begs the question: do these conditions increase the likelihood of ballet dancers developing ankle osteochondritis or osteoarthritis?
Not only do advanced imaging systems such as the CurveBeam pedCAT – which was not used in this particular study – reveal the bones’ proper anatomic alignment, but they also enable a close investigation of cartilage quality, which isn’t possible with traditional MR imaging. Bilateral, weight bearing three-dimensional views of the foot and ankle are therefore the most cogent means for specialists to create comprehensive treatment regimens and surgeons to better visualize their surgery plans for better operation outcomes.
Most importantly, however, is Dr. Russell’s recent study confirms the use of orthopedic imaging to examine pointe dancers’ ankles in detail will only continue to offer more insight into the demands placed on the ankle by dancing in this way, ultimately leading to safer instruction, more accurate treatment of injuries, and faster recovery times.
As the orthopaedic and podiatric specialties continue to advance, there is great potential for technology like CurveBeam’s pedCAT system to revolutionize care.
Recent research highlighted the importance of weight bearing scans to the understanding of foot and ankle anatomy, suggesting a role for pedCAT in both a research and clinical setting. “Rotational Dynamics of the Normal Distal Tibiofibular Joint with Weight-Bearing.
Computed Tomography” a 2016 study published in Volume 37 of Foot & Ankle International sought to determine the normal range of motion for uninjured distal tibiofibular joints. Researchers hoped this reference would be useful as a comparison when assessing injured and repaired ankles.
Until recently, all measurements of this motion had been conducted on cadavers or through non-weight bearing scans. In contrast, this study used a weight-bearing CT (WBCT) system to survey the ankles of 32 subjects as they stood on one foot, then the other.
They found a “total movement of 1.5 mm and rotation of 3 degrees” in the syndesmosis as the average across subjects. However, the study also found that intersubject variation was extremely high, meaning different people had vastly different ranges of motion despite similar orthopaedic histories.
These differences were not correlated with sex or age. Intrasubject variation, or the difference in movement between a person’s right and left foot, was significantly smaller and more consistent, less than 1 mm on average.
The study therefore concluded “the contralateral ankle should be used as a reference when dynamic alignment of the distal tibiofibular joint is studied.”
In other words, surveying a person’s uninjured ankle will give a better idea of what is normal movement for that particular individual than comparing the injured ankle to a standardized range, like the one this study endeavored to produce.
CurveBeam’s pedCAT technology could have helped researchers eliminate possible errors in these findings. In the article, researchers admitted “it is possible that we were unable to optimize posture and rotation identically on both sides “ as a result of the limited field of view of the imaging equipment.
The device used in the study could only scan a partial foot in a scan. Test subjects had to stand on one foot, then twist and then switch and twist again. Researchers were unable to measure the force with which the subjects moved on each side.
The pedCAT’s field of view accommodates bilateral imaging, which would have allowed researchers to survey both weight bearing feet at the same time, providing helpful insights. The research indicates the importance of weight bearing measurements of a person’s right and left ankle to determine their normal range of motion.
Being able to accurately assess their syndesmosis on one side will help physicians more accurately assess and repair damages to the other.
CurveBeam’s pedCAT technology is the ideal imaging solution because it allows physicians to scan and survey ankles side-by-side for increased accuracy and ease.
CurveBeam and its technical solutions have the potential to revolutionize orthopaedic and podiatric research and care. Visit us at curvebeam.com to learn how pedCAT and other CurveBeam technologies can make a difference in your practice!
Within the last two decades, Cone beam Computed Tomography (CBCT) imaging applications have diversified in both the medical and industrial applications. Developments in medical diagnostic applications were pioneered in the Dental industry in 1996, when the first commercially produced Dental/Maxillofacial CBCT scanner was introduced.
A number of factors contributed to the commercialization of cone beam CT. First was the introduction of more cost efficient flat panel detectors that were capable of achieving higher resolution. The first dental CBCT systems had image intensifiers coupled with CCD cameras to capture the data used for creating images. These systems were prone to distortions and required frequent calibration. Compared to the image intensifier systems, the new FPDs were less bulky, which in turn allowed the scanners themselves to be designed and manufactured to take up less room. Because the detectors were significantly more sensitive to x-ray photons, the x-ray sources could be made smaller as well.
Faster computer processors using multiple cores, greater working memory capacity, and larger capacity storage drives – all at cheaper prices – made CBCT technology more affordable.
Once CBCT technology was available to the dental specialties, the 3D data was used to create planning and placement tools for dental implants. CBCT technology also revolutionized orthodontics, airway and sinus evaluation, and maxillofacial surgery and reconstruction planning and evaluation.
CBCT applications continue to grow because of the technology’s affordability, equipment design and ease of use.
In the next parts of this series on CBCT technology, we will look into the different components of a CBCT system in more detail.
One advantage of CT imaging over MRI imaging is the ability to scan patients with metal implants. However, the CT scans may still suffer from severe artifacts that usually show up as streaks or dark, obscured areas. Although artifact reduction technologies continue to improve image quality, metal implants can still pose a major challenge to diagnosis.
Radiologists and foot and ankle specialists are routinely impressed with the pedCAT’s ability to visualize complex post-surgical cases. To schedule an in-office demo to view these cases in more detail, contact your CurveBeam sales representative today.
The pedCAT cone beam CT imaging system for the foot and ankle provides high resolution, high quality imaging, even with metal implants and hardware.
pedCAT scans give you one of the highest resolution views of the foot and ankle available.
And those high resolution views are infinite – physicians can view the foot and ankle from the axial, coronal and sagittal planes by scrolling through .5 mm slices. The average medical CT slice, in comparison, is about 1 mm – 5 mm thick.
Plus, a pedCAT scan is high resolution from every dimension. To understand what that means, here’s a crash course in 3D imaging: Just like a photo is made up of two-dimensional pixels, a foot scan is made up of three-dimensional voxels. Think of a Rubik’s Cube that’s made up of millions of microscopic mini cubes. Because the voxels are uniform, or isotropic, a pedCAT scan is the same high resolution in all planes.
A medical CT , meanwhile, is often anisotropic. Imagine that same Rubik’s Cube, but this time made up of microscopic rectangular bricks. A typical medical CT image may only be high resolution in one dimension. The other two dimensions will be relatively blurry. The degree of blurriness will depend on the voxel thickness.
If your practice or medical facility prefers not to settle for anything less than the best, it’s time to consider a pedCAT.
“We are focusing on quality metrics. It’s becoming important for us to become champions of quality in our institutions,” said Dr. Vijay Rao, MD, in a course at the meeting.
How could a pedCAT add value to your practice?
We might get an idea by looking at a comparable new technology. Breast tomosynthesis mammography provides 3D imaging for breast cancer screening, similar to the way the pedCAT provides 3D imaging for the foot and ankle. Breast tomosynthesis technology can detect breast cancers earlier than traditional 2D mammography, and can more accurately pinpoint the size, shape and location of abnormalities, according to the Massachusetts General Hospital Imaging Department.