Dr. Czihal replies

摘要

To the Editor: We appreciate the comments from Milchert, et al on ourstudy evaluating the involvement of femoropopliteal arteries in giant cell arteritis (GCA). In their letter, they describe 2 cases with different clinical manifestations of extracranial GCA, including 1 patient with suspected vasculitis of the lower extremities. They discuss the difficulties in discriminating between vasculitis and arteriosclerosis in clinical practice. Detection of a homogenous, hypoechogenic, circumferential vessel wall thickening by color duplex sonography (CDS) has been shown to be specific for diagnosis of extracranial GCA. However, we agree with Milchert and colleagues that the accuracy of this method in evaluating the carotid and lower extremity arteries may be hampered in patients exhibiting concomitant, calcified arteriosclerotic lesions. It is of interest in this context that, as a result of the high prevalence of arteriosclerosis of lower extremity arteries in the elderly population with GCA, 18F fluo-rodeoxyglucose-positron emission tomography (FDG-PET) imaging has a low specificity for diagnosis of vasculitis of the lower extremity arteries7. It is our hypothesis that concomitant arteriosclerosis of the lower extremity arteries results in the sonographic "beaded tube" appearance of the innermost layer of the thickened vessel wall in vasculitis of the femoropopliteal arteries (Figure 1).