Ultrasound centre frequency shifts as a novel approach for diagnosing giant cell arteritis

Objective: Giant cell arteritis (GCA) is a treatable, but potentially sight- and life-threatening form of systemic vasculitis. Prompt and correct diagnosis is therefore important. Temporal artery biopsy (TAB) is the gold standard for diagnosing GCA, but is associated with risks. There is no reliable non-invasive technique for the diagnosis of GCA. Ultrasound centre frequency shift (CFS) is a novel technique that uses high-frequency ultrasound and the analysis of the centre frequency of the ultrasound pulse, which is dependent on the size of the microstructures in the tissue. This provides an objective measure of the scattering microstructures in the tissue, and thus has the potential to discriminate changes due to disease. The aim of this study was to assess ultrasound CFS as a means of discriminating arteries affected by GCA from healthy arteries. Method: TAB specimens from 68 subjects, 53 female and 15 male, with a mean age of 73 (range 52–87) years, with suspected GCA were examined using ultrasound ex vivo and the CFS was analysed. The temporal arteries were then examined histopathologically. Results: Histopathological examination revealed that 25 of the 68 biopsies of the temporal artery showed inflammatory changes in the vessel wall compatible with GCA. The ultrasound CFS decreased less in TAB-positive than in TAB-negative temporal arteries (p < 0.05). Conclusions: This proof-of-principle study indicates that ultrasound CFS has the potential to detect GCA in temporal arteries. Further technical development will be needed before in vivo examination can be performed and the clinical applicability can be assessed.