Tl-201 SPECT in pseudotumoral multiple sclerosis

A patient with multiple sclerosis had a pseudotumoral plaque evident on a b rain MRI that was indistinguishable from a malignant brain tumor. TI-201 SP ECT showed uptake of TI-201 In the lesion with indices of 1.55 and 1.96 at 30 minutes and 3 hours, respectively. The retention index was 26.4%. The pa tient had clinical and radio-logic spontaneous improvement, and the results of TI-201 SPECT performed 3 months later were negative. TI-201 uptake in m ultiple sclerosis pseudotumoral plaques has not been described before. In t his patient, TI-201 SPECT could not differentiate a large multiplesclerosis plaque from a malignant brain tumor.