Diffusion tensor imaging of the knee may be better at predicting bone growth than standard radiographic bone imaging examinations on children. 

Bone age studies are important because they offer clinicians insight into endocrine and orthopedic disorders, as well as other underlying growth problems that might require therapy in children. There are a couple of different methods used to track growth in children, including a simple radiograph of the hand, but because they predict long bone growth based on phalangeal measurements, final heights are often overestimated. 

A study published this week in Radiology examines the utility of diffusion tensor imaging (DTI) of the knee for providing more accurate height measurements in children. Researchers found that it could be a suitable alternative due to its demonstration of physeal and metaphyseal structure and physeal function. 

“In the physis, parallel columns of chondrocytes extend into the ossifying cartilage of the metaphysis along the longitudinal axis of the bone,” corresponding author Diego Jaramillo, from the Department of Radiology at Columbia University Medical Center, and co-authors explained, “Physeal DTI depicts the anisotropic diffusion along these columns as a series of tracts parallel to the length of the bone. The magnitude of tract volume and length correlates with height gain.” 

Previously, it was not known whether DTI physeal measures could be used to predict height velocity or final height, so the researchers analyzed the findings from DTI studies from healthy children who underwent knee MRI scans (completed between 2012 and 2016) to assess their prediction value. Children had their height measured at the time of their scan and either one year later (height velocity) or after growth cessation (total height gain).