Ultrasonography for GCA diagnosis may reduce need for temporal artery biopsies
Colour duplex sonography (CDS) may prove useful in diagnosing giant cell arteritis (GCA), providing high specificity and positive predictive value and allowing for a significant reduction in temporal artery biopsies, a study has shown.
The retrospective study included 293 patients (mean age 72 years; 67 percent female) who contributed to 377 CDS scans of temporal arteries and axillary arteries (AXs). GCA was confirmed in 118 patients. Clinical data revealed that 73 percent of patients had already received high-dose glucocorticoids for 17 days.
Among the 55 new referrals for treatment (<7 days of glucocorticoid exposure), CDS was able to diagnose GCA with a sensitivity of 63.3 percent, specificity of 100 percent, positive predictive value of 100 percent and negative predictive value of 64.5 percent. Sensitivity increased to 81.8 percent in the presence of jaw claudication and high inflammatory markers.
During the observation period, the rate of temporal artery biopsies dropped from 72 to 36 (42 to 25 percent; p=0.002). CDS was positive in 21 percent of 89 follow-up scans in asymptomatic individuals and in 37 percent of 78 patients experiencing clinical flares.
The number of halos decreased over time, with only new or flaring patients showing a halo in four or more sites. Axillary halo diameter was 1.6 mm at referral and diminished to 1.4 mm at follow up (p=0.01) or during flares (p=0.02).
Findings of the present study support the potential role of CDS evaluation in diagnosing GCA and detecting GCA patients with disease relapses, researchers said, adding that the introduction of CDS in routine care should lead to a significant reduction in temporal artery biopsies.