CHICAGO — Vascular ultrasound, when performed by experienced sonographers, demonstrated high sensitivity and specificity for the diagnosis of large-vessel giant cell arteritis, according to data presented here.
Researchers noted that these findings suggest the imaging modality has implications for first-line use in patients with suspected large-vessel disease.
“In this disease subset of GCA patients, there is an unmet need for earlier recognition and earlier diagnosis,” Berit Dalsgaard Nielsen, MD, a doctoral fellow at Aarhus University in Denmark, said during a press conference. “We performed this study to look into the performance of ultrasound. New EULAR recommendations recommend GCA patients have an early imaging test and patients who present with cranial symptoms, which is typical of GCA when it effects the cranial arteries, ultrasound for the temporal arteries is the recommended imaging test.”
Nielsen added that “For patients who do not present with cranial symptoms, different modalities can be used for confirmation of large vessel involvement, but no priority for the modalities is given because there are no studies that compare [them], and studies on diagnostic accuracy for large vessel involvement are sparse.”
Nielsen and colleagues performed clinical and laboratory examinations, as well as ultrasound and PET scans prior to treatment initiation, among 90 patients with suspected GCA. Patients were considered for inclusion if they were aged 50 years; had CRP>15 mg/L or ESR>40 mm/h; had either cranial symptoms, new-onset claudication, protracted constitutional symptoms or polymyalgia rheumatica symptoms. The researchers excluded patients with recent or ongoing glucocorticoid or DMARD treatment, those with a previous diagnosis of GCA or polymyalgia rheumatica, or large vessel inflammation mimicking large-vessel GCA.
The control group was comprised of patients whose clinical diagnosis was not GCA (n = 34), and the case group included patients with GCA with large vessel involvement (n = 46). Ultrasound was performed by experienced sonographers who were blinded to the results of patients’ PET scans.
Axillary or carotid artery ultrasound was positive among 36 of 46 patients with large-vessel GCA; no control patients had a positive large vessel ultrasound, yielding a specificity of 100% and a sensitivity of 78%. Excluding carotid artery assessment from the analysis only decreased sensitivity to 76%. Using an intima-media thickness cutoff of 1.0 mm in the axillary artery, 70% sensitivity and 93% specificity was obtained. The agreement between sonographers' assessment of the ultrasound images was almost perfect, Nielsen said.
“We think these results implicate that ultrasound should not only be a first-line imaging test in patients presenting with cranial symptoms, but also in patients suspected of GCA presenting with constitutional symptoms,” Nielsen said. “If this examination is included in the standard examinations in the fast-track clinics, it may overcome the delay in diagnosis and patients can be treated earlier. It may also spare the unneeded examinations performed in these patients.”– by Stacey L. Adams
Nielsen BD. Abstract 2905. Presented at ACR/ARHP Annual Meeting, Oct. 20-24, 2018; Chicago.
Disclosure: Nielsen reports no relevant financial disclosures.