Differential diagnosis between brain tumor recurrence and radionecrosis is still problematic. MR Spectroscopy Imaging (MRSI) is useful in differentiating between these two histologically and radiologically distinct entities. Six methods with different combination of metabolic parameters were used to compare 37 lesions examined by 2D/3D MRSI. The lesional and contralateral comparison of choline-containing compounds and lactate using long echo time achieved the highest sensitivity and specificity. Choline to creatine ratio showed low specificity. The distinction of regressive recurrence as a separate entity is helpful in the effort to discern the complexity of events leading to new enhancing lesions in neurooncologic patients.