According to the American Journal of Roentgenology (AJR), rickets and classic metaphyseal lesions (CMLs) have distinct radiographic signs, and radiologists can reliably distinguish between the two.
"Recognition that CMLs mostly occur in children younger than 6 months and are unusual in children older than 1 year may assist interpretations," wrote corresponding author Boaz Karmazyn from Riley Hospital for Children in Indianapolis, IN.
Karmazyn and colleagues' study included children under the age of two who had knee radiographs from January 2017 to December 2018 and either had rickets (25-hydroxy vitamin D 20 ng/mL and abnormal knee radiographs) or knee CMLs and a pediatrician's diagnosis of child abuse. Eight radiologists interpreted radiographs for rickets or CML diagnoses independently, rating confidence levels and logging associated radiographic signs.
Finally, CML children were younger than rickets children (3.9 percent vs 65.7 percent > 1 year old). For CML, the rate of false-positive moderate or high-confidence interpretations was 0.6 percent, and for rickets, it was 1.6 percent. Only one child with CML and low vitamin D received a combined CML and rickets interpretation.
Reiterating that less- and more-experienced pediatric and non-pediatric radiologists had high diagnostic performance in differentiating rickets and CML – regardless of vitamin D deficiency, with few false-positive interpretations for these diagnoses – the authors of this AJR article concluded that "findings suggestive of both rickets and CML should be viewed as indeterminate."
Reference: DOI: 10.2214/AJR.22.27729