Color-coded sonography in suspected temporal arteritis - experiences after 83 cases

Color-coded sonography is an interesting option for the diagnosis of temporal arteritis. We present our experiences regarding examination technique and diagnostic accuracy, comparing biopsy and clinical results in a series of 83 patients with suspected temporal arteritis. A dark halo around the vessel wall (representing inflammatory oedema), reduced or absent vessel wall pulsations (demonstrated by M mode), and vessel occlusions were used as diagnostic criteria. Forty-eight patients underwent biopsy of the temporal artery following ultrasound examination. Comparing these findings with biopsy yielded a sensitivity of 73%, specificity of 93%, positive predictive value (PPV) of 96%, and negative predictive value (NPV) of 58%. The halo sign alone had a lower sensitivity (67%). Comparison with overall clinical assessment (n = 83) yielded a sensitivity of 65%, specificity of 100%, PPV of 100%, and NPV of 73%. Irregular atherosclerotic vessel wall changes were the main differential diagnosis. Important pitfalls were false focus setting, too much/less color gain, and 'bifurcation halo'. In conclusion, a positive sonographic result in combination with typical clinical signs might replace the need for biopsy, while a negative result should not be used for exclusion of temporal arteritis. Considering the low PPV and high NPV of the clinical criteria defined by the American College of Rheumatology, color-coded sonography is a useful tool in the noninvasive diagnostic workup of temporal arteritis.