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

Tag Archives: weight bearing CT

The University of Kansas Announces Grant Funding for Knee Imaging Biomarkers Acquired from Weight Bearing CT

Patient with knee pain

The University of Kansas Medical Center Research Institute Department of Rehabilitation Medicine has received a grant from the National Institute of Arthritis Musculoskeletal and Skin Diseases (NIAMS), one of the 27 Institutes and Centers at the National Institutes of Health (NIH), to fund three years of research on the usefulness of bilateral weight bearing CT imaging and the critical need for more sensitive and affordable imaging biomarkers.

Osteoarthritis (OA) is the most prevalent form of arthritis, and the knee is the most commonly affected weight-bearing joint. The high cost of clinical trials creates a barrier for effective treatment development. Therefore, introduction of more specific and sensitive biomarkers could help to advance therapeutic development by reducing the time and sample sizes required for clinical trials.

Proposed Outcomes

There is an urgent need for imaging biomarkers that allow for identification of the best time in which patients will respond to treatment, and a means to analyze the efficiency of interventions. Early studies demonstrated the diagnostic value of bilateral weight-bearing CT in identifying knee OA symptoms accurately, as well as the feasibility to detect meniscal tears not detected by non-weight bearing MRI.

The grant from NIAMS will fund a study to validate the proposed imaging biomarkers and begin the qualification process for more responsive OA imaging biomarkers acquired using low-dose, bilateral standing CT imaging. Substantial advantages are offered over traditional radiographic biomarkers, including increased responsiveness to temporal changes in the joints, and a better reflection of the symptoms and severity of the disease. Additionally, this research will determine the prognostic validity of standing CT findings for detecting progression and worsening pain in people who currently suffer from or are at risk for knee OA.

Long-Term Impact

With the support of NIAMS, this research holds promise to detect joint damage earlier, and accelerate the pace of scientific discovery and clinical trials. The continuing impact will be evident through a shift in knee joint imaging with an improved biomarkers for monitoring knee OA disease features. If the additional meniscal extrusions detected on bilateral standing CT are clinically relevant, then standing CT could improve identification of the most appropriate patients for clinical trials – those at risk of rapid OA progression. Successful completion will provide improved biomarkers that will help those who suffer from knee OA through making clinical trials more affordable and accelerating therapeutic improvement.

For more information on visualizing cartilage and menisci in the knee using standing CT arthrogram versus MRI, click here.

RSNA Daily Dispatch

The Radiological Society of North America (RSNA) commenced its 103rd Annual Meeting in Chicago on Sunday, Nov. 26, 2017.

@judywawira tweeted a photo of  a standing room only session at the RSNA Annual Meeting on Nov. 26, 2017.
@judywawira tweeted a photo of a standing room only session at the RSNA Annual Meeting on Nov. 26, 2017.

Attendees from around the world gathered to learn about the latest advances in imaging.

In an afternoon session titled “Open Gantry Systems: Advances, Challenges, and New Applications,” Dr. Jeffrey H. Siewerdsen, PhD, of Johns Hopkins Biomedical Engineering, discussed the vast applications of cone beam CT for interventional and diagnostic imaging. The devices presented included C-arms for image guided surgery, Cone Beam CT guided radiation therapy systems, and diagnostic imaging devices for breasts, dental/ENT, and orthopedic extremities.  Siewerdsen emphasized the  revolutionary potential of weight-bearing extremity devices in orthopedic specialties, and mentioned the CurveBeam pedCAT and LineUP systems.  He also discussed the image quality parameters of Cone Beam CT and artifacts specific to this type of imaging. He offered suggestions on how to quantify image performance of such systems, many of which are relatively new and do not have established quality metrics in the imaging community. Finally, he presented some of the newest Cone Beam CT devices to come to market, including the extremely compact CurveBeam InReach made primarily for hand and wrist imaging.

Need Bunion Surgery? A Weight Bearing CT Scan Could Help You Decide

When a patient appears to have a bunion, a physician typically orders traditional foot X-Rays as part of the clinical evaluation. The X-Rays capture three views of the foot- dorsoplantar, medial oblique, and lateral. But is this enough information to understand complex, three-dimensional object such as the foot? 

A growing number of foot & ankle specialists are advocating that there may be better way to evaluate this common deformity.

“Weight bearing computed tomography scans are beginning to take our understanding to the next level,” Dr. Paul Dayton, DPM, of Des Moines, IA, said in a roundtable discussion on bunions published in the Foot & Ankle Specialist academic journal. “Once you see the connection between coronal rotation and what we have traditionally evaluated on AP radiographs, it opens up a whole new understanding.”

On X-Rays, physicians have to “mentally interpolate” the valgus component of the bunion because they do not adequately capture the frontal plane, said Dr. Robert Weinstein, DPM, FACFAS, of Atlanta, explained in a CurveBeam case study.  

“Since the condition is a tri-plane deformity, we need to understand all of the components and their angular values contributing to the deformity,” Weinstein said. “Better deformity analysis leads to better pre-operative planning, surgical execution, and post-operative results.”

The new data on the coronal position is “exciting” because it explains so many of foot and ankle specialists’ previous questions, Dayton said.  

Weight bearing CT imaging also allows for evaluating deformities that involve external rotation. Rotation of one or more metatarsals, including displacement of the sesamoids, cannot be clearly seen in standard foot X-ray imaging. The lack of the weight-bearing aspect in traditional medical CT imaging means the physician cannot evaluate displacement and rotation under load.

Hallux Valgus Blog Post Image 1
One component of the deformity that is seldom quantified is external rotation, or frontal plane deviation. The presence of rotation of the hallux implies a more complex deformity. A very careful assessment of the first metatarsophalangeal joint architecture, including sesamoid position, their condition, and erosion or flattening of the crista on the inferior first metatarsal head is essential.

It has long been known that in hallux valgus or bunions the relationship between the metatarsal head and the sesamoids is altered,” Andy Goldberg, MD, MBBS, FRCS (TR and Orth), of Stanmore, United Kingdom, told Lower Extremity Review magazine. he said. “The sesamoid bones should sit underneath the metatarsal head, while in hallux valgus the big toe drifts off the sesamoids and the tip of the big toe points outwards. But our research has shown that in many cases the cartilage is worn, which in essence is localized arthritis, and we believe that this could affect the outcome of surgery.”

rotated first met and sesamoids

CubeVue, the pedCAT weight bearing CT imaging system’s custom visualization software, allows physicians to create oblique and frontal-plane images of varying angles and thicknesses from the weight bearing CT data.
CubeVue, the pedCAT weight bearing CT imaging system’s custom visualization software, allows physicians to create oblique and frontal-plane images of varying angles and thicknesses from the weight bearing CT data.

Weight bearing CT images could have an impact on the technique a physician selects to repair a bunion, Dr. Dayton said.

“The knowledge that the sesamoids can be in normal position medial and lateral to the crista yet look dislocated on the AP X-ray because of pronation completely changes our mindset about the need for capsular balancing,” Dayton said. “We can see that in those cases supination corrects the deformity.”

Orientation of the Subtalar Joint: Measurement and Reliability Using Weight Bearing CT Scans

Is there a reliable method to predict the type and perhaps the extent of osteoarthritis one might find in the ankle? Based on a recent article, which the examined the varus and valgus orientation of the talus and the configuration of the subtalar joint under weight bearing conditions, the possibility is there.

“A majority of the patients with ankle osteoarthritis present with an asymmetric wear pattern (eg, varus or valgus type),” according to a study published in 2009 by Valderrabano V, Horisberger M, Russell I, Dougall H, Hintermann B. titled, “Etiology of ankle osteoarthritis.”

Evaluation of these wear patterns, however, remained a challenge until recently, when Nicola Krähenbühl, MD, Michael Tschuck, Lilianna Bolliger, MSc, Beat Hintermann, MD, and Markus Knupp, MD published “Orientation of the Subtalar Joint: Measurement and Reliability Using Weightbearing CT Scans.” (Foot & Ankle International® 2016, Vol. 37(1) 109–114.)

Osteoarthritis of the ankle joint is relatively common and found in 1 percent of the world’s population, and a majority of those patients present with an asymmetric wear pattern (eg, varus or valgus type), according to the authors. Furthermore, up to 60 percent of the patients suffering from an osteoarthritic ankle joint develop talar tilt with progression of the osteoarthritic process.

Current research suggests this condition is caused by deformities of the lower leg and knee joint, ligamentous laxity, tendon dysfunction and neurologic disorders. Recently, it has been proposed that the adjacent joints and, particularly, the subtalar joint may have a major influence on this process.  “However, it is rather difficult to evaluate the orientation

of the subtalar joint using conventional radiographs; CT scans would be more appropriate,” the authors posit.

To distinguish between varus/valgus configuration of the subtalar joint, Van Bergeyk et al introduced the subtalar vertical angle (SVA) in 2002 using non weight bearing CT scans. “Today, weight bearing CT scans can be performed, leading to a better understanding of the functional anatomy of the hindfoot,” the article states.

Weight bearing CT technology became available in 2012. Weight bearing imaging only had been available in 2-dimensional X-Ray imaging prior to this, but weight bearing combined with computed tomography was needed to properly measure the SVA without superimposition of non-relevant anatomy that might throw off the measurement, including analyzing the shape of the subtalar joint. The subtalar joint is especially difficult to clinically and radiographically assess in 2D, due to the superimpositions, and attempts to artificially stress the joint and then scan using a conventional (non weight bearing) CT produced inconsistent results.

“Using weight bearing CT scans, we assessed the reproducibility of the SVA and analyzed the orientation of the subtalar joint in patients with asymmetric ankle osteoarthritis. We hypothesized that the SVA would provide reliable and reproducible measurements in varus ankles presenting with a varus subtalar joint and valgus ankles with a valgus orientation of the subtalar joint, respectively,” the authors said.

Using the new technology to view the joints, including utilization of the SVA measurement, the authors concluded the SVA measurements were reliable and consistent. “In our cohort, varus osteoarthritis of the ankle joint occurred with varus orientation of the subtalar joint whereas in patients with valgus osteoarthritis, valgus orientation of the subtalar joint was found,” the study said.

The authors found the results for the healthy cohort were significantly different, suggesting the orientation of the subtalar joint may play an important role in the development of ankle joint osteoarthritis.

Weight bearing CT not only allowed the authors to clinically and radiographically assess the ankle joints under the patient’s normal weight bearing conditions, but it also enabled them to make consistent and reproducible measurements.

Panel Recap: Dr. Michael Chin, DPM, Speaks about pedCAT at FABI

Dr. Michael Chin, DPM, and Arun Singh, President & CEO of CurveBeam
Dr. Michael Chin, DPM, and Arun Singh, President & CEO of CurveBeam

His decade old X-Ray system was failing, and feeling like a warrior without his weapon, Dr. Michael Chin, DPM, knew it needed to be replaced fast.

“We could have gotten a DR system, but at the end of the day, I wanted something that was unique, and something that would change the way I practice,” Dr. Chin said.

Dr. Chin participated in a panel discussion about new technology at the Foot and Ankle Business Innovations meeting in Chicago on Jan. 30. Dr. Chin practices at The Running Institute in downtown Chicago.

Dr. Michael Chin, DPM, at FABI

Dr. Chin uses the pedCAT for all of his X-Ray and CT imaging. His X-Ray revenues cover the device’s monthly capital lease payment, and the approximately 20 CTs he and his associate order every month provide his practice with an additional revenue stream.

Dr. Chin said he is able to order a CT scan and his staff can get payer authorization in the same day. This saves his patients from having to come in for a follow-up visit.

“We can fill that slot that we would have used for a follow up with another patient,” Dr. Chin said.

Weight Bearing CT Imaging for Cuboid Subluxations

Dr. Michael Chin, DPM, presented how weight bearing CT imaging has changed how he evaluates cuboid subluxations at the American Academy of Podiatric Sports Medicine meeting held near the West Point Military Academy campus in early September, 2015.

Dr. Chin began using the pedCAT in his office in February of this year.

Not much research is out there on how to use plain radiographs to measure cuboid subluxations, Dr. Chin said in his lecture, titled, “Cuboid Syndrome…The Other Side of Heel Pain.”

Dr. Chin has tested using a bilateral oblique projection to understand the cuboid/ metatarsal relationship, and has been able to observe a slide between the head of the fourth metatarsal and the head of the cuboid.

An MRI could be ordered to see the condition of the peroneal tendon, but the study would be limited because the scan would not be weight bearing, he said.. A traditional CT scan would provide great  visualization of the bone, but would provide no information on anatomic alignment.

The pedCAT weight bearing CT imaging system is excellent for evaluating stress fractures, sesamoids, periosteal changes, or anything medullar, Dr. Chin said. Another benefit is he can measure the exact degree of subluxation between the cuboid and the fourth metatarsal head.

Dr. Chin displayed pedCAT images depicting  pre and post-reduction views of a cuboid subluxation.

chin-lecture
pedCAT scan of a pre-surgical patient with cuboid subluxation. Dr. Chin was able to reduce the subluxation to 2.18 mm.

Dr. Chin practices at The Running Institute in Chicago.

AOFAS Annual Meeting – CurveBeam Symposium Recap

Weight bearing CT is a vital tool for determining the cause of inexplicable pain, and also for avoiding painful surgical complications.

That was the takeaway message from a talk by Dr. Phinit Phisitkul, a clinical associate professor of orthopaedics at the University of Iowa. He shared some of his most interesting cases at a CurveBeam sponsored symposium held during the AOFAS Annual Meeting in Long Beach during the evening session.

We’ve selected three of his cases to share on this blog:

18-year-old male with Noonan Syndrome & severe flat foot: The patient presented with an unusual amount of pain that was difficult to diagnose on plain X-Ray. A weight bearing CT scan revealed he had a severe deformity – a congenital vertical talus. He also had severe impingement.

Vertical Talus - Weight Bearing CT
Vertical Talus – Weight Bearing CT
Impingement - weight bearing CT
Impingement – weight bearing CT

58 year-old male with ankle arthritis: The patient presented with a lot of pain in the ankle joint. A weight bearing CT scan showed a subluxation of the ankle joint and dramatic impingement of the calcaneal fibula. Interestingly, the subtalar joint was in pristine condition. Dr. Phisitkul determined the patient was a good candidate for ankle replacement and hindfoot realignment, and that his subtalar joint could be spared.

Calcaneal-fibular impingement and arthritis - Weight Bearing CT
Calcaneal-fibular impingement and arthritis – Weight Bearing CT

41-year-old female with Hallux Valgus: A weight bearing CT scan revealed a bone spur on the patient’s first metatarsal head. If the doctor had done a normal release, the spur may have ended up pinching the sesamoid. Instead, he performed a lateral release and excised the bone spur.

1st MT Bone Spur - Weight Bearing CT
1st MT Bone Spur – Weight Bearing CT

 

 

 

 

Weight Bearing CT in Everyday Practice

“In my opinion, weight bearing CT will be the standard of care in the next couple of years,” Dr. Alex Tievsky, DPM, said in a lecture at the Graham International Implant Institute 8th Annual Symposium in Miami, on April 17. “This is really the future of not just foot and ankle, but the future of medicine.”

“2D is beginning to be phased out,” Tievsky said. “Now we’re beginning to see the problem from all angles and all planes, so this is super helpful from that respect.”

Dr. Tievsky presented a number of cases where he benefited from access to weight bearing 3D technology in his office.

Clinical Case #1

A 50-year-old female presented with bilateral flat feet for 20 years. She had heard about the HyProCure procedure, which corrects hindfoot misalignment through a minimally invasive procedure. She was eager to have the procedure done, no matter the cost. Dr. Tievsky took a pedCAT scan, and found she had a severe talar coalition.

talar calc coalition coronal left

“How many times do you catch a coalition on an X-Ray? It’s hard,” Dr. Tievsky said. “Sometimes you can see a halo sign, but it’s often missed. On the first visit, I was able to tell her, we either have to resect this coalition or we have to do a fusion. It’s impossible to get this level of information on an X-Ray.”

Clinical Case #2

A 16-year old girl came in with first metatarsal head pain. She had already been to two other podiatrists in the last six months, and they had prescribed steroid injections.

The pedCAT revealed a fracture on her fibular sesamoid that is extremely easy to miss on X-Ray.

fractured sesamoid

“Within her first 10 minutes in the office, we had a diagnosis,” Dr. Tievsky said. “We treated her appropriately. We immobilized her for eight weeks and gave her a bone stimulator. And she was pain free, three podiatrists later. She was happy, her mom was happy, and she never came back.”

Clinical Case #3

A patient presented with a lateral plantar fasciitis, a talo-tarsal dislocation, back pain for five years, knee pain, and hip pain.

A pedCAT revealed she had a tumor in her bone and it was eroding it. “There was no way we would have caught it on X-Ray,” Dr. Tievsky said. “We sent her out for oncology. It could have a malignant tumor, and we could have saved her life.”

Cyst Coronal

The scan is quick to take and you have a full work-up in about three minutes, Dr. Tievsky said as a closing statement. “This is a super important tool,” he said. “I’m kind of biased. I love this now. I can’t practice without it.”

Weight Bearing CT Scans for the Evaluation of Implant Arthroplasty Candidates

Weight bearing CT scans can be critical to a proper diagnosis, even for routine procedures.

In the following case, for example, a patient’s X-Rays indicated that he would be a good candidate for a metatarsal head hemi-implant arthroplasty. However, when the patient sought a second opinion, a weight bearing CT (pedCAT) scan revealed the true condition of the metatarsal head, and the surgical plan was considerably altered as a result.

A 60 year-old male presented complaining of a many year history of 2nd metatarsophalangeal joint pain, especially joint stiffness and pain. His pain increased with attempted 2nd MTPJ dorsiflexion.  In gait, he felt pain when rolling onto the ball of the foot.  His first surgical opinion recommended a metatarsal head hemi-implant arthroplasty .

Due to the excessive bony superimposition on the patient’s lateral X-Ray, it is difficult to accurately assess the shape of the 2nd metatarsal head.  A bone fragment can be visualized over the dorsum of the first or second metatarsal heads.  The AP weight bearing images demonstrate 2nd metatarsophalangeal  joint space narrowing.

Implant Arthroplasty Candidate X-Ray X-Ray 2

The patient sought a second opinion from a podiatric surgeon who offers in-office weight bearing CT services. The podiatrist performed a pedCAT scan and found the 2nd metatarsal head had sustained an old fracture. The pedCAT scan revealed that the dorsal 50% of the 2nd metatarsal head had been avulsed dorsally and a portion of the metatarsal head presented as a dorsal loose body.  The 2nd metatarsal head didn’t have the bone stock or bone volume to support a hemi-implant. The second opinion recommended recontouring the metatarsal head and performing an interpositional arthroplasty. The patient chose to have the second surgeon perform his surgery.

fractured 2nd MT head pedCAT weight bearing CT

A CT scan is not typically ordered to evaluate feet preoperatively.

“We are all trained to believe our eyes and to believe the information present in X-Ray images.  In this case it is assumed that the 2nd metatarsal head has a normal contour, length and bone volume.  The X-Rays demonstrate joint space loss and justify the hemi-implant arthroplasty, but adequate bone volume is required for implant stability and fixation. You just assume it’s going to be OK,” said Dr. Kent Feldman, DPM. “And if you do that as a routine, you’re going to get caught over and over and over in the operating room making mistakes or making assumptions that aren’t necessarily true.”

Dr. Feldman integrated a pedCAT into his surgical practice in 2012.

Dr. Gary Briskin: The pedCAT is the Future

“It’s the future – embrace it. It’s your future – control it.”

Dr. Briskin lectures on weight bearing CT imaging for foot 7 ankle
Dr. Briskin lectures on weight bearing CT imaging for foot 7 ankle

Dr. Gary Briskin delivered this motivating message at the Foot & Ankle Business Innovations conference in Chicago on Jan. 23.

Dr. Briskin, of University Foot & Ankle Institute in Santa Monica, Cali,  discussed how the pedCAT weight bearing CT system has improved his practice since his group acquired one last year.

His main take-away points were:

– The pedCAT gives you the advantage when it comes to diagnosing pathology.

“You can solve that Lisfranc case no one else can,” Dr. Briskin said. “It opens up the midfoot, which historically has been a problem for us.”

– The pedCAT allows him to clearly determine if bones and joints are completely fused after surgery.

“I do a lot of lapidus procedures,” Dr. Briskin said. “My concern; is this patient fused adequately to start bearing weight?” The exact level of fusion is visible with a pedCAT scan 5 – 6 weeks later, and with minimal scatter.

– Radiologists like the pedCAT images

“I think I’m getting a better CT, because it’s weight bearing and I think the quality is far superior. We get all of our CTs read by a radiologist. We have everything sent digitally. And the feedback we get is they are also impressed with the quality of the images.”