Résumé
Magnetic resonance imaging (MRI)and computed tomography had been used to detect the neurologic lesions of the Behcet's disease.However,there are a number of cases which can not be detected by conventional imaging studies in neuro-Behcet's disease.To overcome this problem,magnetic resonance spectroscopy (MRS)has been introduced in several autoimmune diseases involving central nervous system such as neuropsychiatric lupus,but which was rarely performed in Behcet's disease.In the present study,we report two cases of neuro-Behcet's disease that showed normal MRI but abnormal proton MRS (1HMRS)findings.MRS in two cases revealed a reduction of the N-acetyl aspartate (NAA)/creatine (Cr)ratio in the substantia nigra and thalamus,respectively, which were the areas without abnormality on MRI,suggesting a functional defect of neurons in these areas.In a case with thalamic dysfunction,abnormal NAA/Cr ratio was normalized in parallel with clinical improvement after treatment with high-dose steroids and immuno-suppressive agents.These observa-tions suggest that MRS may be useful to early detect the functional abnormality in neuro-Behcet's disease and to monitor neurologic status after treatment with immuno-suppressive agents.