Objectives: To explore the sensitivity to change of colour Doppler ultrasound (CDUS) in giant cell arteritis (GCA).
Methods: This was a blind, prospective study composed of 30 consecutive patients diagnosed with GCA. In 25 of the cases this was their first episode of GCA, and 13 of the cases were relapses. All participants had presented with at least 1 branch involvement in the basal sonography, and steroid treatment had been initiated. A CDUS was performed every 2 weeks during the first month, and every 4 weeks thereafter, until halo disappearance was observed in the bilateral parietal and frontal branches of the temporal superficial artery.
Results: Thirty-eight episodes of GCA in 30 different patients (19 women and 11 men; mean age, 79.24±4.76 years; range 70-88) were followed. Dark halo disappearance occurred in 95% of cases. The mean time until halo disappearance was observed was around 11 weeks, with 50% of cases showing halo disappearance within the first 8 weeks. The relapse cases appeared to have less arterial wall affectation than the primary GCA cases, reduced erythrocyte sedimentation rate ESR and an earlier loss of the halo sign. Patients with a smaller number of affected branches required less time for halo disappearance.
Conclusions: CDUS shows a sensitività to change in GCA. Halo disappearance is rare before two weeks, and it frequently persists during the first two months after initiating steroid therapy. Our data emphasise the advantages of using CDUS to monitor GCA activity.