LAUSR

We read with great interest the article by Keser and Aksu [1] published in Rheumatology International, entitled “Diagnosis and differential diagnosis of large-vessel vasculitides”, in which the authors provided an excellent review of diagnostic criteria and the differential diagnosis of Takayasu and giant cell arteritis. We would like to discuss the role of high-resolution vessel wall imaging, a magnetic resonance imaging (MRI) technique not mentioned by the authors, in the diagnosis of giant cell arteritis and secondary superficial temporal arteritis. We present two cases of temporal arteritis caused by giant cell arteritis and varicella zoster virus infection, respectively. A 55-year-old man presented with a history of recentonset headache that worsened when the left temporal region was touched, associated with neck and bilateral shoulder pain. Laboratory tests revealed an elevated erythrocyte sedimentation rate. The patient had no skin lesion. 3-T MRI showed no brain parenchymal alteration, and findings of brain magnetic resonance angiography were normal. Highresolution vessel wall imaging showed smooth and concentric wall thickening and enhancement of the left superficial temporal artery (Fig. 1a–c). The patient was treated with corticosteroids for presumed giant cell arteritis. He recovered clinically, with alleviation of pain and reduction of the erythrocyte sedimentation rate. A 60-year-old man presented with headache, reduced consciousness, and vesicular cutaneous lesions on the left side of his face. 3-T MRI showed no brain lesion, and findings of magnetic resonance angiography were normal, but the patient exhibited skin thickening in the left temporal and frontal regions. High-resolution vessel wall imaging showed concentric wall thickening and enhancement of the left superficial temporal artery (Fig. 1d–f). Polymerase chain reaction analysis of the cerebrospinal fluid showed positivity for varicella zoster virus. The patient was treated for varicella zoster virus vasculitis, using acyclovir and pulse therapy with corticosteroids. He recovered clinically, with the alleviation of headache and improvement of his level of consciousness. High-resolution vessel wall MRI encompasses different MRI sequences that achieve sufficient resolution and contrast between the vessel wall and overlying tissue, enabling the differentiation of vascular pathologies that were uncompleted evaluated with luminal imaging [2]. This technique has been used primarily for the assessment of intracranial diseases, and is currently part of state-of-the-art MRI protocols for the detection of vascular diseases [3], enabling diagnosis and differentiation of entities such as intracranial atherosclerotic plaque, vasculitis, reversible cerebral vasoconstriction syndrome, and arterial dissection [4]. High-resolution vessel wall imaging enables the direct visualization of vessel wall inflammation and edema, showing thickening and multifocal homogeneous, smooth, intense, concentric enhancement of the vessel wall, while atherosclerotic plaques present as nonconcentric heterogeneous wall abnormalities. It can also aid the tracking of treatment response [5]. Presumably, arterial wall enhancement in patients with vasculitis is due to increased permeability of the endothelium, with contrast leakage from the lumen into the arterial wall [4]. Rheumatology INTERNATIONAL