Can osteoporosis and osteomalacia be distinguished radiographically?

No. Classically, osteoporosis has a picture frame appearance, with a sharp cortex and decreased density otherwise, while osteomalacia has decreased density with blurring of the trabeculae and cortex. However, in practice osteoporosis and osteomalacia are difficult to distinguish from one another, which is why some advocate labeling all such cases by the generic term osteopenia.