7T MRI as a Powerful Tool to Detect Small- and Medium-Size Vessel CNS Vasculitis.

Imaging can help to diagnose CNS vasculitis. Yet so far, no imaging studies of CNS vasculitis at 7T are available. We share our experience of vessel wall imaging (VWI) at 7T in patients with suspected vasculitis. All included patients (n=45) underwent a clinically approved 7T MRI comprising high-resolution arterial TOF angiography as well as high-resolution VWI with T1 sampling perfection with application-optimized contrast using different flip angle evolution (SPACE) and T1 SE acquired pre- and postcontrast. Twenty-three patients showed negative and 22 patients showed positive VWI at 7T. Ten of 22 7T VWI-positive cases were suggestive of vasculitis with 9 patients showing VWI of large- and medium-size vessels and 1 patient VWI of small vessels. Small-vessel vasculitis was only depicted with 7T VWI, but not 3T VWI. Our work demonstrates that diagnosing CNS vasculitis, especially small-vessel vasculitis, is feasible at 7T and highlights the potential of high-field VWI encouraging further studies in this field.