Increased frequency of temporal acoustic window failure in rheumatoid arthritis: a manifestation of altered bone metabolism?

Assessment of intracranial vessels includes transcranial Doppler (TCD). TCD performance requires intact temporal acoustic windows (TAW). Failure of TAW (TAWF) is present in 8–20% of people. There have been no reports on TAWF in rheumatoid arthritis (RA). Altogether, 62 female RA patients were included. Among them, 20 were MTX-treated and biologic-free, 20 received infliximab, and 22 tocilizumab. The controls included 60 non-RA women. TAWF, temporal bone thickness, and texture were determined by ultrasound and CT. BMD and T-scores of multiple bones were determined by DEXA. Several bone biomarkers were assessed by ELISA. In RA, 54.8% of the patients had TAWF on at least one side. Neither TAW could be identified in 34% of RA subjects. In contrast, only 20.0% of control subjects had TAWF on either or both sides (p < 0.001). In RA vs controls, 53.0 vs 2.9% of subjects exerted the trilayer, “sandwich-like” structure of TAW (p < 0.001). Finally, in RA vs controls, the mean temporal bone thickness values of the right TAW were 3.58 ± 1.43 vs 2.92 ± 1.22 mm (p = NS), while those of the left TAW were 4.16 ± 1.56 vs 2.90 ± 1.16 mm (p = 0.001). There was close association between TAWF, bone thickness, and texture (p < 0.05). These TAW parameters all correlated with age; however, TAW failure and texture also correlated with serum osteoprotegerin. TAW bone thickness inversely correlated with hip BMD (p < 0.05). TAWF, thicker, and heterogeneous temporal bones were associated with RA. These features have been associated with bone loss and OPG production. Bone loss seen in RA may result in OPG release and stimulation of bone formation around TAW.