1T magnetic resonance imaging in the diagnosis of giant cell arteritis: comparison with ultrasonography and physical examination of temporal arteries.

OBJECTIVE: To assess the usefulness of 1T magnetic resonance imaging (MRI) of temporal arteries and to compare 1T MRI with duplex ultrasonography (US) and physical examination of temporal arteries for the diagnosis of giant cell arteritis (GCA) in patients with suspected GCA.

METHOD: The superficial temporal arteries of 20 consecutive patients with a suspected diagnosis of GCA were examined using a 1T MRI scanner. Fat-saturated multislice T1-weighted spin-echo images were acquired perpendicularly to the orientation of the vessel. In all cases, MRI results were compared to US and temporal artery examination findings. Temporal artery biopsies were performed in all patients.

RESULTS: Mural contrast enhancement of the temporal arteries on MRI had a sensitivity of only 33.3% and a specificity of 87.5% for the diagnosis of biopsy-proven GCA. Compared with the diagnosis of GCA by the American College of Rheumatology criteria, MRI had a sensitivity and specificity of 27.2% and 88.9%, respectively. Temporal artery abnormalities on physical examination and the presence of a hypoechoic halo on US had a higher sensitivity (66.7% and 77.7%, respectively) and a higher specificity (100% for both) compared to MRI findings.

CONCLUSION: 1T MRI is not useful for the diagnosis of GCA because of its low sensitivity. US and physical examination of temporal arteries had a better diagnostic accuracy. However, our data does not exclude a diagnostic role for higher-resolution MRI.