Implications of a new radiological approach for the assessment of Paget disease

In the present study, we quantified the proportion of skeletal involvement of Paget disease of bone (PDB) not captured by an abdominal X-ray. We also analyzed extension and severity over time and tested the hypothesis that X-rays from selected areas could replace bone scans for mapping PBD. We examined whole skeletal (99m)TC-MDP bone scans from 208 consecutive untreated patients. Pagetic bones included in an abdominal X-ray were delimited; disease extension and activity were calculated using Coutris's index as well as Renier's index and serum alkaline phosphatase (AP) values, respectively. The study period (1965-2007) was divided into quartiles according to the date of the diagnosis. The percentage of patients with PDB captured by an abdominal X-ray was 79 % (95 % CI 74-85 %). In the last quartile vs. the first quartile, PDB was diagnosed at a more advanced age (67 ± 11 vs. 57 ± 9 years, respectively), with a lower median extension (4 vs. 7) and similar median activity (32 vs. 35) but less activity through median AP values (183 vs. 485 UI/L). The skeletal locations to X-ray in order to capture up to 93 % of PDB extension were the abdomen, skull with facial bones, and both tibias. In conclusion, one-fifth of patients are underdiagnosed when assessing prevalence of PDB by an X-ray of the abdomen, and there is a secular trend to presentation in older patients with a decreasing extension of the disease. A set of X-rays that includes abdomen, skull with facial bones, and both tibias provides a reliable alternative to bone scans.