CNS involvement in neuro-Behcet syndrome: An MR study

BACKGROUND AND PURPOSE: Behcet disease (BD) is a multisystem vasculitis of unknown origin in which neurologic involvement has been reported in the ran ge of 5% to 10% in large series. Reports on clinical and radiologic aspects of neuro-Behcet syndrome (NBS) are in general limited in number. Our purpo se was to determine the MR patterns in patients with NBS who had neural par enchymal involvement and to correlate our findings with possible vascular p athophysiology. METHODS: The MR images of 65 patients with NBS and neural parenchymal invol vement were reviewed. In a subgroup of patients who had serial MR studies, we evaluated the anatomic-radiologic location and distribution of the lesio ns and whether they corresponded to any vascular territory, and studied the ir extension, enhancement patterns, and temporal course. RESULTS: The most common imaging finding in NBS patients who had neural par enchymal involvement was a mesodiencephalic junction lesion with edema exte nding along certain long tracts in the brain stem and diencephalon in 46% o f the patients. The next most common location of involvement was the pontob ulbar region, seen in 40% of the cases. Three primary cervical spinal cord lesions and one case of isolated optic nerve involvement were observed. CONCLUSION: The parenchymal distribution of lesions in NBS appears to suppo rt the hypothesis of small-vessel vasculitis; mainly, venular involvement. The anatomic distribution of intraaxial veins of the CNS explains the predo minant involvement of the brain stem structures observed in our patients. T his pattern of lesion distribution might help to differentiate NBS from oth er vasculitides as well as from the inflammatory-demyelinating diseases of the CNS, such as multiple sclerosis.