RESUMO
PURPOSE: Little is known about the diagnostic concordance of images provided by ultrasound probes with emitting frequencies below or above 20 MHz for the diagnosis of giant cell arteritis (GCA). METHODS: We compared, using Cohen's kappa statistic, data obtained with an 18-MHz and a 22-MHz probe for the ultrasonographic evaluation of temporal arteries in 80 patients referred for suspected GCA. RESULTS: The halo sign was found in 25% of cases with the 18-MHz probe and in 35% with the 22-MHz probe. The compression sign was positive in 42% of cases with the 18-MHz probe and 48% with the 22-MHz probe. GCA was finally diagnosed in 20 patients (25%). The kappa coefficient of agreement was 0.76 (P < .001) for the halo sign, and 0.75 (P < .001) for the compression sign. CONCLUSIONS: Images obtained by 18 MHz and 22-MHz frequency probes showed a good level of agreement for the diagnosis of GCA, but the 22-MHz probe yielded a correct diagnosis of GCA in 3 of the 7 patients in whom examination with the 18-MHz probe was negative.