What is the accuracy of radiography for the diagnosis of osteoporosis?

Updated: Jan 19, 2021
  • Author: Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR; Chief Editor: Felix S Chew, MD, MBA, MEd  more...
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Answer

Answer

Conventional radiography is insensitive for diagnosing osteoporosis. At least 30% of the bone mass must be lost before it is recognized.

The precision error (coefficient of variation) is 1% for SPA. The precision error is affected not only by the measurement of technique but also by patient characteristics. Precision error tends to increase in an elderly or osteoporotic population due to factors such as greater difficulty in repositioning and lower mean BMD.

SXA cannot separate trabecular and cortical bone components. The precision of this method is around 1-2%, and the accuracy is ±2-4%.

With DPA, the error of precision and accuracy is 2-3%. The precision of DEXA is 2-6%, and the accuracy is about ±5%. One unavoidable source of error in the dual-photon technique is the distribution of fat in the path of the radiation beam. It is possible to correct for an evenly distributed fat layer across the scanning path, but an uneven distribution introduces error into the measurements. DEXA has some limitations, including artifacts such as degenerative disk disease and osteophytosis in the older spine that can cause a false elevation of BMD.


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