ISO 13485 Certified | ISO9001 Certified Request more information or an in-office demo (267) 483-8081

Kent State Faculty and Students Research the Use of Weight Bearing CT to Effectively Assess Magnitude of Hallux Valgus Deformity

Hallux valgus, bunion in foot on white background
Hallux valgus, bunion in foot on white background

Hallux valgus is a triplane deformity. In patients with this deformity, the sesamoids displace from their normal alignment. Recent evidence suggests that, according to researchers, “the magnitude of this displacement can be determined by the coronal plane sesamoid rotation angle.” Podiatric doctors often use weight-bearing radiographs to determine the magnitude of the hallux valgus deformity. This is a crucial step in planning surgical correction. However, conventional foot radiographs have long been problematic due to:

  • geometric distortion
  • unreliable measurements made between different observers
  • limited imaging in the coronal plane
  • measurable differences between weight-bearing and non-weight-bearing images

CT scanning addresses these problems. It allows “cross-sectional imaging of the anatomical parts in all three planes of the foot without typical radiographic distortion.” In other words, doctors are able to look at slices of the foot for better data. CT scanners also allow for three-dimensional reconstruction of the foot.

The Kent State University College of Podiatic Medicine recently acquired a CurveBeam pedCAT bilateral weight-bearing CT scanner via a grant funded by the Ohio College of Podiatric Medicine (OCPM) Foundation. In the wake of this acquisition, the College of Podiatric Medicine students and faculty proposed three research projects. Each one has the potential to break new ground in the specialty. A team of KSUCPM researchers has completed the first project, which focuses on the evaluation of hallux valgus deformity in the coronal plane of the foot.

Differences in Rotation Angle Between Two Extreme Weight-Bearing Positions

Using the weight-bearing CT scanner, this study was designed to determine, according to the researchers, “the effect of different weight-bearing foot positions on the coronal plane sesamoid rotation angle as compared with standard sesamoid axial studies.” Study data demonstrated “significant differences in the rotation angle between the two extreme weight-bearing positions.” Sesamoid rotation angles, the researchers noted, were “significantly higher in the pronated foot position.” Sesamoid rotation angles from the weight-bearing CT supinated position correlated with those values.

Weight-Bearing CT Scan Determination Should Replace Forefoot Axial Studies

These results strongly suggest that “weight-bearing CT scan determination with the foot in a non-affected weight-bearing position should replace forefoot axial studies as the accepted imaging standard.”

Learn more about how Weight-Bearing CT in diagnosing Hallux Valgus patients here.

Researchers propose reproducible method to quantify syndesmosis displacement based on spatial WBCT data

Sprained ankle black x-ray
Sprained ankle black x-ray

The syndesmosis is located just above the ankle where the tibia and fibula meet, providing stability to the ankle joint while allowing for its motion. A sprain, twist, rotational injury, or break to the ankle can stretch and tear the ligaments that support the syndesmosis. Syndesmotic injuries occur in up to 18 percent of all ankle sprains and 23 percent of all ankle fractures. However, the limitations of 2D imaging make a diagnosis and operative treatment of syndesmotic ankle injuries challenging.

Despite high accuracy and sensitivity, CT scans may underestimate the extent of syndesmotic lesions because of non-weight bearing conditions.

Weight bearing cone beam CT (WBCT) is an alternative imaging technique with numerous advantages, including relatively low radiation dose.

Researchers in the United States and Belgium aimed to develop a reproducible method using WBCT to quantify displacement, translation and rotation of the fibula caused by subtle syndesmostic injuries. Current methods use a single slice of a CT volume. The researchers proposed segmenting a volume out of bilateral ankle CTs superimposing the healthy ankle on the contralateral ankle to compare the deviation of the fibula to quantify the extend of the lesion.

The researchers conducted a study on eighteen patients with a unilateral syndesmotic lesion. The results were described in a study titled,  “Templating of Syndesmotic Ankle Lesions by Use of 3D Analysis in Weight-bearing and Nonweightbearing CT”.

For those patients with a high ankle sprain (n = 12), bilateral imaging was performed with weight-bearing cone-beam computed tomography (CT), while non-weight-bearing CT was used for those with fracture-associated syndesmotic lesions (n = 6). To quantify the syndesmotic lesions, changes between the most lateral aspect of the lateral malleolus and the anterior and posterior tubercle in the healthy, stationary fibula were compared to those of the affected patients, using a control group of seven studies.

Deviations were calculated using defined anatomical landmarks on computer assisted design (CAD) software, rather than via manual methods.

The study found there were significant differences in the tibiofibular configuration between injured and healthy ankles.

The study concluded that

  • The method was accurate in assessing subtle syndesmotic injuries.
  • In the case of fracture associated with syndesmotic injury, it offered a precise description of the displacement related to the integrity of the distal tibiofibular syndesmosis.
  • In a case with pronounced fibular comminution, the amount of shortening could be preoperatively calculated, facilitating reconstruction of the fibula.

Click here to read about a previous study in which cadavers were scanned via WBCT imaging in an effort to shed light on the rotational dynamics in syndesmosis.

EFAS Workshop: Weight Bearing CT Applications and Techniques

Curvebeam will host an Applications and Techniques Workshop on  October 4th at the 12th EFAS International Congress in Geneva, Switzerland.

Dr. Arne Burssens, who recently completed a fellowship at the University of Utah in Salt Lake City,  will be presenting on Hindfoot Detection and Planning. He will discuss how to measure and assess hindfoot alignment and plan for correction in a 3-Dimensional plane.

Dr. Cesar de Cesar Netto, a fellow at Johns Hopkins University in Maryland, will demonstrate CurveBeam’s Automatic Measurements toolset, which can perform common foot and ankle measurements in seconds

. The event will be hosted in the Paris Room from 12:30 p.m to 2 p.m.

CurveBeamEFASInsertWBCTISGFront

Visit the CurveBeam exhibit at EFAS to learn more about our weight bearing CT imaging systems.

Also, plan to attend the WBCT ISG Scientific Session on Oct. 5.

Weight Bearing CT A Key Topic at EFAS 2018

2-EFAS-PromoToolkit_SocialMediaBanner_1024X512October 4-6 marks the 12th EFAS International Congress in Geneva, Switzerland. This year’s theme, State of the Art Foot and Ankle Surgery, focuses on the latest clinical and scientific findings in the foot and ankle community.

Weight bearing CT imaging has emerged as an essential tool for the proper evaluation of deformities of the ankle, midfoot, forefoot, and hindfoot. EFAS attendees will have multiple opportunities to learn about the modality in the main program, including the following podium lectures:

  • 3D biometrics: A prospective comparative evaluation of the Foot Ankle Offset using weight bearing CT semi automatic software”, Presented by Dr. Francois Lintz
  • How are coronal alignments of the knee and hindfoot correlated ? A clinical study of 124 lower limbs using 3D weight bearing imaging”, Presented by Dr. Francois Lintz
  • Weightbearing CT and MRI findings of Stage II Flatfoot Deformity: Can We Predict Patients at High-Risk for Foot Collapse?”, Presented by Dr. Cesar de Cesar Netto

In addition, several posters on display will review recent research efforts involving weight bearing CT, including:
– “Distance mapping analysis of the Foot and Ankle complex joints using Weight Bearing CT in varus and valgus deformities”, Dr. Francois Lintz

Comparative study of 3D versus 2D first intermetatarsal M1M2 angle measurement using Weight Bearing CT”, Dr. Francois Lintz
Templating of Acute and Chronic Syndesmotic Ankle Lesions in Weightbearing and Nonweightbearing CT”, Dr. Arne Burssens
Clinical and Radiological Outcome after a Medial Calcaneal Osteotomy Assessed by Weightbearing CT”, Dr. Arne Burssens

Intrinsic Anatomical Risk Factors in High Ankle Sprains Determined by Computed 3D CT Analysis”, Dr. Arne Burssens

Foot Alignment in Basketball and American Football Elite Athletes. Are they different?”, Dr. Cesar de Cesar Netto

Instability of the First Ray and Hallux Valgus in Patients with Adult Acquired Flatfoot Deformity (AAFD): A Weightbearing CT Study”, Dr. Cesar de Cesar Netto

The Weight-Bearing CT International Study Group will be hosting a special session on Friday, October 5th featuring presentations by Dr. Arne Burssens, Dr. Cesar de Cesar Netto, and Dr. Francois Lintz. To RSVP, click here.

WBCT Scientific Session at EFAS International Congress

WBCT

The Weight-Bearing CT International Study Group (WBCT ISG) will host its next scientific session during the EFAS International Congress. The session, open to all attendees, will occur on October 5 between 12:30 and 2:00 pm in the Roma Meeting Room at the Starling Geneva Hotel and Conference Centre. Attendees can register for the scientific session at www.wbctstudygroup.com.

The WBCT ISG promotes dialogue and collaboration on weight-bearing CT research initiatives. Membership is comprised of global foot & ankle surgeons, and includes affiliate members from the radiology and biomechanical engineering disciplines.

Foot and ankle specialists from seven healthcare institutions representing the United States, Germany, Belgium and Finland will speak at the session. Group members are working to create standardized protocols for measurements and analysis.

Lunch will be provided to all participants in the scientific session.

The session, moderated by Dr. Francois Lintz, MD, will review the following topics:

o   Results of a 5 year, 10,000 scans experience with WBCT. Impact on costs, radiation exposure and time spent; Presented by Dr. Martinus Richter MD, PhD

o   Advanced imaging of syndesmotic injuries: where are we now and what can we do with weight-bearing CT; Presented by Dr. Shadpour Demehri, MD

o   The use of distance mapping in combination with WBCT; Presented by Dr. Sorin Siegler, PhD

o  Centre of rotation of the subtalar joint: novel research in the use of WBCT to assess dynamic function; Presented by Dr. Andrew Goldberg, MD

o   Deformity corrections and 3D planning based on the WBCT; Presented by Dr. Kris Buedts, MD
 
o   Use of Low dose WBCT in cartilage and bony lesions of the ankle; Presented by Dr. Oliver Michelsson, MD

o  Three-dimensional modeling of the weight bearing ankle syndesmosis; Presented by Dr. Arne Burssens, MD

CurveBeam is a proud co-sponsor of the WBCT ISG.

Download the official event brochure here

Name *

Email *

Cone Beam Computed Tomography with Load Technique (WBCT) Allows Correct Evaluation of Foot and Ankle Anatomy

61 xrayImaging studies are important tools in diagnosis, therapeutic decision-making, and evaluation of functional results in the area of ankle and foot performance. The most commonly used resources are conventional X-rays with load, ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI). The initial diagnostic investigation often uses conventional X-rays with load to reproduce the three-dimensional bone relationships in the ankle and foot more accurately. However, the information acquired from this method can be limited.

Computed tomography (CT) provides for high-resolution images of the ankle and foot in different axes. Fractures, degenerative changes, bone healing, surgical planning for osteotomies, arthrodeses, and arthroplasties are all instances in which CT is the go-to imaging tool. However, it’s not a perfect option. One distinct issue with conventional CT is the fact that the technology cannot reproduce images of feet and ankles experiencing body weight load.

Over the last ten years, the cone beam computed tomography with load technique (WBCT) proved feasible for the instances mentioned above. It also offers high reproducibility of the real situation of the ankle and foot when body weight is factored in.

A review of relevant clinical studies in multiple databases from January 1999 to October 2017, titled “Weight-Bearing Computed Tomography of the Foot and Ankle: An Update and Future Direction,” analyzed the available literature on WBCT imaging in patients with foot and ankle disorders.

This review concluded that WBCT imaging allows correct evaluation of foot and ankle anatomy with the patient in a standing position, providing images with high spatial resolution, short image acquisition time, low dose of radiation, and costs which are similar to other available imaging technologies. This diagnostic tool can be used for decision making in the treatment of deformities of the ankle, hindfoot, midfoot, and forefoot.

In addition to the fact that WBCT imaging can be done with a patient in an orthostatic position, the advantages of this new technology include:

  • high resolution
  • 3D reconstruction
  • fast image acquisition
  • low radiation dose
  • small device footprint
  • lower cost than conventional CT

CurveBeam is the maker of pedCAT, which provides bilateral, weight-bearing scans of the foot and ankle.

New Case Study Showcases Advancements in Measurement of Joint Space Width in the Knee

jswUnder the current standard of care, joint space width (JSW) measured on Weight Bearing radiographs suffers from poor sensitivity to detection of knee osteoarthritis (OA). It also does a poor job of tracking symptom progression. 2D radiographic JSW is limited by dependence on X-Ray beam alignment with the medial tibial plateau as well as temporal and spatial heterogeneity of structural progression of knee osteoarthritis. Fortunately, 3D JSW measured on Weight Bearing CT images has the potential to overcome these limitations.

LineUp Scanner from CurveBeam Used to Create 3D Datasets

To test this assertion, 3D JSW measurements were collected on 11 participants in the Multicenter Osteoarthritis Study. Then, 3D datasets were reconstructed from Cone Beam CT projections. These images were captured using the LineUP scanner manufactured by CurveBeam. Standardized response means (SRM) were calculated to assess the ability of Weight Bearing CT to detect changes in joint space width over time.The preliminary data presents evidence that 3D JSW is sensitive to changes in joint space comparable to what was reported in other studies measuring JSW by radiographs or MRI.

Weight Bearing CT: More Sensitive and Accurate

Weight Bearing CT is showing the potential to offer better data, even when overlapping anatomy is a factor. It is proving to be more sensitive and accurate for detecting osteophytes and subchondral cysts when compared to conventional fixed-flexion radiography. This technology provides 3D biomechanically accurate views of bone morphology, alignment, and joint spaces.

“Weight Bearing CT could replace radiographs as the recommended means of assessing knee OA,” says Dr. Neil Segal, MD, Professor, and Director of Clinical Research in the Department of Rehabilitation Medicine at the University of Kansas Hospital, and the lead researcher on this study.

To learn more, download the case study by completing the form below.

Name *

Email *

Study Calls CBCT “Method of Choice” for Hand and Wrist Bone Assessment

Female patient at orthopedic medical exam in doctor's hospital office, traumatology and medical consultation for hand wrist injury

A study published in the International Journal of Biomedicine concludes Cone Beam CT (CBCT)  imaging is the “method of choice” for compound anatomical structures, such as the wrist, and post-traumatic changes in bone tissue.

“Considering the low dose radiation and high image quality,” CBCT could be used as a priority method of choice to assess the structure of wrist and hand bones and be done as a first step in diagnostics, replacing standard radiography,” according to the study, which was led by A. Yu Vasiliev PhD, MD, at Moscow State University of Medicine and Dentistry.

The wrist and hand are one of the regions in the human body most prone to injury and disease.  Only one-fifth of incapacitation is the direct result of injury or disease. Many cases of incapacitation are instead due to mistakes made in diagnosis and treatment, according the study. Vasiliev and his team examined the capabilities of cone-beam computed tomography (CBCT) in the assessment of the structure of wrist and hand bones.

The study appeared in a 2013 issue of the International Journal of Biomedicine.

Vasiliev obtained a Cone-beam CT scan of the wrist and hand of a group of voluntary patients, which included 40 members aged 22 – 68 years. A Magnetic resonance imaging (МRI) exam was also performed on 80 percent of the volunteers, multi-slice CT scan was performed on 40 percent of the volunteers, and digital microfocus radiography and standard radiography exams were performed on 63 percent of the volunteers.

When all 40 CBCT scans were examined, structural changes of wrist and hand bones were detected in 77.5 percent of cases, and consolidated fractures and false joints of bones were detected in 10 percent of cases. All the changes were also detected by the multi-slice CT images and digital microfocus X-Rays, but were not defined on standard X-Rays.

The results demonstrated that CBCT provides high efficiency in detection of form, measurements and structural changes of bones of the anatomic region. The cone beam CT images of wrists and hands provided high-resolution, detailed mapping of bone structure, as well as accurate differentiation of bone trabeculae and minor structural changes and defects.

A new generation of cone-beam scanners makes it possible to obtain high-quality images without exposing the patient to a high dose of radiation. This facilitates more and better examinations in orthopedics and traumatology for better patient outcomes.

CurveBeam designs and manufactures Cone Beam CT imaging equipment for the orthopedic and podiatric specialties. To access the full study, please click here.

New Algorithm Uses CT Data to Create 3D Map and Better Assess Osteoarthritis

knee arthritis stock

Engineers, radiologists and physicians based in the UK have developed a new technique for improving clinical imaging. It uses an algorithm to create a detailed three-dimensional map of a patient’s joint using computed tomography (CT) data. The team, led by co-author Tom Turmezei, Ph.D. of Cambridge University, recently reported on their breakthrough with a journal article titled “A new quantitative 3D approach to imaging of structural joint disease,” which appeared in the June 2018 edition of Scientific Reports.

The team knew that the ability to assess OA with 2D radiographs was not good enough to detect subtle changes that could have important implications for patients, doctors, and researchers. To meet this challenge, they worked to develop a new algorithm for the structural assessment of joints including hips, knees and ankles in 3D. Their recent technical validation study showed the technique was successful.

The algorithm maps joint space width to the nearest tenth of a millimeter. Mapping joint space width in 3D from clinical CT data has the potential to enhance understanding of osteoarthritis and how patients progress to joint failure—leading to better and earlier interventions.

Early Detection Gives Osteoarthritis Patients More Options

The 3D mapping technique has the potential to be more than twice as sensitive as radiographs in detecting small changes in joint space widths. Using the algorithm, clinicians will be able to use CT scans to map a marker of osteoarthritis across a joint. Why does it matter? Because early detection leads to earlier treatment. Doctors could identify patients with disease earlier than the current gold standard, allowing important interventions to be started before the joint fails. Patients will have the opportunity to try lifestyle changes and physiotherapy instead of immediately facing surgery.

All clinical CT imaging was performed on a 64-slice Siemens Definition AS system.

“It will be an important next step to use JSM to investigate whether differences in positioning and load-bearing have any effect on joint space width in 3D,” the authors wrote. “A straightforward solution for prospective studies would be to perform knee and ankle CT in a standing position (as used in clinical practice), and to standardise supine hip positioning by strapping feet together.”

Evaluating New Therapies

In addition, the new 3D method will likely allow researchers to determine whether new therapies in development are effective in a realistic timescale for clinical trials. This is something that has not been possible using radiographs.

CurveBeam designs and manufactures Cone Beam CT imaging equipment for the orthopedic and podiatric specialties. Bilateral, weight bearing scans of the foot and ankle give physicians the information necessary to assess the biomechanical spatial relationships and alignment of the lower extremities.

To learn about a recent grant awarded to the University of Kansas to study joint space biomarkers via weight bearing CT, click here.