Whitney Palmer

Tomosynthesis Shows Promise in Knee Imaging

Published on the March 30, 2012, DiagnosticImaging.com website

By Whitney L.J. Howell

Tomosynthesis has been around for more than a decade, most recently being used in breast imaging, but new research indicates it could be useful in diagnosing osteoarthritis of the knee.

Investigators from Boston University School of Medicine (BUSOM) determined tomosynthesis is more proficient than radiography in identifying the hallmarks of knee osteoarthritis — bony spurs and fluid-filled cysts. As a modality, tomosynthesis is much like an X-ray/CT hybrid that can be conducted while the patient is standing. It’s technically an X-ray, but the method produces CT-like thin slices that can give you 360-degree views.

The flexibility of letting the patient stand makes tomosynthesis a good fit for knee imaging, said Daichi Hayashi, PhD, a BUSOM musculoskeletal radiology research fellow and lead author of the study published in April issue ofRadiology.

“CT is a more sophisticated technology than tomosynthesis, but patients

(a) Radiograph shows no obvious osteophyte in the right lateral femur (arrow). (b) Tomosynthesis image shows an osteophyte in the same compartment (arrow) as in a. (c) Coronal proton density-weighted MR image (9000/10) confirms presence of osteophyte (arrow); a focal cartilage defect is also noted (arrowhead). Courtesy Radiological Society of North America

must be lying down in order for it to work. That prevents us from getting images of the knee being exposed to tension that usually arises from standing or walking under normal conditions,” Hayashi said. “Tomosynthesis lets us image the patient when the knee is exposed to gravity and weight.”

Hayashi’s team received a grant from GE to study whether tomosynthesis could provide acceptable images for osteoarthritis diagnoses. To date, it is the first study to examine the use of this modality in knees.

Overall, the team imaged 40 adults — 80 knees total — over age 40, irrespective of knee pain or pre-existing osteoarthritis. Using tomosynthesis, MRI, and radiography, they screened four locations in the knee for any bony spurs or cysts. Results showed tomosynthesis identified 178 bony spurs, and radiography pinpointed 150. Additionally, tomosynthesis caught more than double the number of cysts — 31 compared to 15.

Current research, published in the January 2011 Radiology, reported tomosynthesis is also superior to radiography in highlighting rheumatoid arthritis in the hands and wrists. In these cases, tomosynthesis identified about 20 percent more lesions.

Even though it offers greater specificity, the spurs tomosynthesis identifies might not be of significant importance, Hayashi said. It discovers smaller spurs that are less strongly associated with pain than the larger spurs found through radiography. This difference shows tomosynthesis isn’t wholly superior to X-ray technology and that more research is needed to determine the extent to which it can actually contribute to the clinical management of osteoarthritis, he said.

To read the remainder of the article: http://www.diagnosticimaging.com/musculoskeletal/content/article/113619/2052825

March 30, 2012 - Posted by wjpalmer | Healthcare | 360-degree knee images, Boston University School of Medicine, Daichi Hayashi PhD, diagnosing knee osteoarthritis, grants to study tomosynthesis, tomorsynthesis as a better modality than X-ray, tomosynthesis, tomosynthesis and knee osteoarthritis, tomosynthesis less expensive than MRI, tomosynthesis less radiation than CT scans