Assessment of the cranial involvement pattern of giant cell arteritis with 3T magnetic resonance imaging

Objective. To noninvasively determine the involvement pattern of the cranial arteries in giant cell arteritis (GCA), with high-resolution magnetic resonance imaging (MRI). Methods. The superficial cranial arteries of 21 patients with suspected GCA were examined using a 3T high-field MRI scanner. Postcontrast T1-weighted spin-echo images were acquired with submillimeter spatial resolution, to assess mural thickness and lumen diameter of the major cranial arteries on both sides of the head. In all cases, MRI results were compared with findings of clinical examination and laboratory tests. In addition, temporal artery biopsy specimens from 10 patients were examined by histology. Results. MRI sharply revealed all of the major superficial cranial arteries, allowing for an evaluation of their lumen and vessel wall. Nine of the 21 patients were diagnosed as having GCA according to the criteria of the American College of Rheumatology. In all of these patients with clinically diagnosed GCA, multiple cranial arteries showed signs of inflammation on MRI. In I patient, the occipital arteries were inflamed, while the temporal arteries were spared. Conclusion. Postcontrast high-resolution MRI visualizes the major cranial arteries on both sides of the head within a single examination. The cranial involvement pattern in GCA can be assessed precisely and noninvasively. In the majority of GCA patients, several cranial arteries were affected simultaneously, with a predominance of involvement of the frontal branch of the superficial temporal artery. Inflammation of the occipital arteries, with sparing of the temporal arteries, was also encountered.