The World Health Organization has formalized criteria for osteopenia, defined as a bone mineral density score between -1 and -2.5 standard deviations compared to a young adult reference mean (T-score) based on dual energy x-ray absorptiometry (DEXA).
However, radiologists continue to use the term in a generic and qualitative manner to mean decreased bone density, without distinguishing osteopenia and osteoporosis. Because of this discrepancy, some have advocated avoiding the use of osteopenia on bone radiographs and CT in favor of "demineralization" .
History and etymology
Osteopenia derives from the Greek words οστεον (osteon) meaning bone and πενια (penia) meaning poverty .
NB: the spelling osteopaenia is erroneous and should never be used.