Reliability of normal findings on MR imaging for excluding the diagnosis of vasculitis of the central nervous system

OBJECTIVE. We attempt to determine whether angiography is indicated in pati ents with suspected central nervous system (CNS) vasculitis who present wit h negative findings on MR imaging studies. CONCLUSION. MR imaging findings may be negative in the setting of CNS vascu litis confirmed on angiography, indicating that advanced imaging techniques tailored to detect infarction (i.e., fluid-attenuated inversion recovery, diffusion-weighted, and perfusion imaging) may be necessary to enhance the sensitivity of an MR study and that despite the high sensitivity of MR imag ing for CNS vasculitis, angiography may still be required to render an accu rate diagnosis.