What is the preferred imaging evaluation for giant cell arteritis (GCA) imaging?

Updated: Sep 07, 2018
  • Author: Guruswami Giri, MD, FRCS; Chief Editor: Kyung J Cho, MD, FACR, FSIR  more...
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Color Doppler ultrasonography is a method of assessing blood flow qualitatively and quantitatively. In the presence of arteritis, the sonograms show a hypoechoic halo due to edema of the arterial wall. [3] A systematic review and meta-analysis found that, compared with a clinical diagnosis of giant cell arteritis, the ‘halo’ sign at temporal arteries (8 studies, 605 patients) had a pooled sensitivity of 77% (95% CI, 62% to 87%) and specificity of 96% (95% CI, 62% to 87%). [4]

The presence of a halo sign is a criterion used to diagnose giant cell arteritis with color Doppler ultrasonography.  However, the sign is not seen in all patients, and it may also be seen in healthy persons. The halo has also been reported in polyarteritis nodosa. Therefore, the criterion standard is the temporal artery biopsy.

The advantages of color Doppler ultrasound are that it is simple, it is noninvasive, and it can be used to examine several vessels, superficial and deep. Another advantage of this technique is that follow-up scans can be obtained to assess the response to steroids. The hypoechoic shadow becomes mid-echoic in about 2 weeks. With fibrosis, the shadow becomes hyperechoic. [5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]

Other nonradiologic investigations include a determination of the blood sedimentation rate and temporal artery biopsy (see the images below). [16]

CT and MRI are not useful in diagnosing giant cell arteritis; however, they may be used to diagnose complications due to giant cell arteritis, such as stroke.

Giant cell arteritis. Low-power view of a temporal Giant cell arteritis. Low-power view of a temporal artery biopsy sample shows giant cell arteritis.
Giant cell arteritis. Low-power view of a normal t Giant cell arteritis. Low-power view of a normal temporal artery biopsy sample.
Giant cell arteritis. High-power view shows disrup Giant cell arteritis. High-power view shows disruption of the intima with a collection of multinucleated giant cells.

For patient education information, see Temporal Arteritis.

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