In 100 patients (20 male, 80 female) radiographs of the lumbar spine were obtained in both planes, anteroposterior and lateral. Nine readers independently and without specific criteria or training assessed the radiographs for presence of osteopenia in the form of a binary decision. A posteranterior dual x-ray absorptiometry (PA DXA) measurement of the lumbar spine was performed in all patients using the Hologic QDR 1000 bone densitometer. A bone mineral density (BMD) of 0.83 g/cm2 (T-score about 2 SD and 2.5 SD lower than BMD in normal young female and male subjects respectively) was used as a threshold for the diagnosis of osteopenia. Complete agreement amongst the 9 readers was achieved in 43 patients. In 26 more patients at least 8 readers agreed. kappa-coefficients for interobserver variation ranged from 0.458 to 0.691 for reader pairs. For agreement between the observer ratings and the DXA results, kappa-coefficients ranging between 0.347 and 0.555 were found. The vast majority of readers agreed in the diagnosis of osteopenia in cases where the BMD was less than 0.73 g/cm2. Where the BMD was between 0.73 and 1.03 g/cm2 a substantial disagreement was found between reader evaluation and DXA measurement, and also amongst the readers. We conclude from our results that osteopenia can reliably be detected from lumbar spine radiographs by all readers only after a substantial amount of BMD is lost. On the other hand, a diagnosis based solely on PA DXA measurement of the spine may also lack accuracy, due to a substantial influence of degenerative changes of the lumbar spine and aortic calcification.(ABSTRACT TRUNCATED AT 250 WORDS)

Routine radiographs and PA dual x-ray absorptiometry (DXA) of the lumbar spine were performed in 253 patients. A T-score of -2SD (approximately 20% reduction from young normal bone mineral density (BMD)) as measured by DXA, was used as threshold for the diagnosis of osteopenia. A lumbar spine index (LSI) as proposed by Barnett and Nordin was assessed by one radiologist. The correlation between LSI and bone mineral density, measured by DXA, was poor, and our results indicate that osteopenic patients cannot be differentiated from non-osteopenic patients by LSI. 100 radiographs of the lumbar spine were evaluated by 9 observers in order to determine observer variation in the detection of osteopenia. A complete agreement between the readers for the diagnosis of osteopenia was achieved in 43 percent of all radiographs. DXA and observers agreed in 68 to 76 percent of all cases. For a decrease of BMD of more than 60 percent compared to young normal adults, as determined by DXA, all readers agreed in the diagnosis of osteopenia, whereas for higher BMD values the agreement between readers and DXA worsened. The inconsistency between DXA and observer agreement was greatest for patients with a BMD reduction between 10 and 20 percent. The mean values of the kappa-coefficients were 0.574 +/- 0.06 for interobserver variation and 0.437 +/- 0.06 for the agreement between readers and DXA-results. An only moderate kappa-coefficient of 0.573 for the intraobserver variation as determined in one reader was found.