Detection of tumor progression by signal intensity increase on fluid-attenuated inversion recovery magnetic resonance images in the resection cavity of high-grade gliomas.

Increased signal intensity (SI) on fluid-attenuated inversion recovery (FLAIR) magnetic resonance (MR) images in the resection cavity is sometimes observed after partial resection of gliomas. SI in the resection cavity of 44 high-grade gliomas was retrospectively investigated. Twelve of 35 patients with progressive disease (PD) showed SI increase in the resection cavity, and SI increase preceded PD in 6 of these 12 patients. None of nine patients without PD showed SI increase during the follow-up period. The analysis of SI on FLAIR images in the resection cavity had a specificity of 100% and a sensitivity of 34%. Higher sensitivity was found in grade IV tumors than in grade III tumors. SI increase is thus considered as a potent highly specific hallmark for subsequent or coincident tumor progression, which is clinically useful since MR imaging is easily performed during routine clinical examinations.