Aims: We present our preliminary experience with the use of ultrasound in aiding the diagnosis of giant cell arteritis (GCA). Schmidt et al have previously described a hypoechoic or "halo" effect surrounding the walls of affected arteries on examination with ultrasound. We illustrate these features and explore the attributes and limitations of this technique.
Method: Two groups of patients were recruited: (1) patients with suspected GCA awaiting temporal artery biopsy and (2) patients with no history or symptoms of GCA of a similar age group. All the recruited patients underwent ultrasound examination of both temporal arteries. The findings on ultrasound were compared with the results of the histological specimens in group 1. For this study, the histological findings alone were used to define if a patient was suffering from GCA. No biopsies were taken in the patients in group 2.
Results: Out of 26 patients with suspected GCA, seven patients were found to be positive on biopsy, of which six had been identified on ultrasound. Six patients were found to be false positive on ultrasound, but all had moderate-to-severe features of arteriosclerosis on histology. A total of 13 patients were found to be negative on ultrasound and negative on biopsy for GCA, two of these patients had histological features of arteriosclerosis. In the group with no symptoms of GCA (12 patients), in two patients hypoechoic areas were detected. The results presented give a sensitivity of 86%, specificity of 68%, and positive predictive value of 50% for the use of ultrasound in the diagnosis of GCA.
Conclusions: This preliminary study indicates that this test may be helpful in those patients with symptoms suggestive of GCA, but currently we cannot recommend any change of present practice.