Comparison and Significance of Contrast-Enhanced Computed Tomographic Findings of Large-Vessel Vasculitis Before and After Treatment: Differences Between Takayasu Arteritis and Giant Cell Arteritis.

Objective: Imaging is essential for diagnosing large-vessel vasculitis (LVV). During diagnostic imaging, assessing disease activity and vascular damage separately is important. Acute-phase findings represent disease activity, while chronic-phase findings represent vascular damage; however, whether the imaging findings are acute or chronic may be unclear. We investigated how vascular lesions change before and after treatment and whether they were acute- or chronic-phase findings. Methods: Fifty-one patients with LVV who had undergone contrast-enhanced computed tomography (CT) scans from the neck to the pelvis before treatment and 1-4 months after treatment were recruited. Wall thickening, wall contrast enhancement, stenosis, occlusion, dilation, aneurysm, and calcification were semi-quantitatively assessed in 21 vessels from the common carotid to the common iliac artery. Results: Twenty-four patients were diagnosed with Takayasu arteritis (TAK), and 27 with giant cell arteritis (GCA). Wall thickening and wall contrast enhancement improved after the treatment, which was especially significant in the GCA group. No significant differences in stenosis, occlusion, dilation, aneurysm, or calcification were observed before and after treatment. Stenosis and occlusion were more common with TAK, while calcification was more common with GCA. Conclusion: Wall thickening and wall contrast enhancement are acute-phase findings (activity), while stenosis, occlusion, dilation, aneurysm, and calcification are chronic-phase findings (damage). The frequencies of these findings differ between TAK and GCA.