Posttherapeutic intraaxial brain tumor: the value of perfusion-sensitive contrast-enhanced MR imaging for differentiating tumor recurrence from nonneoplastic contrast-enhancing tissue.

Abstract

An enhancing lesion with a normalized rCBV ratio higher than 2.6 or lower than 0.6 may suggest tumor recurrence or nonneoplastic contrast-enhancing tissue, respectively. In these cases, further examination with 201Tl-SPECT may not be necessary. However, when the normalized rCBV ratio is between 0.6 and 2.6, 201Tl-SPECT may be useful in making the differentiation.