Postoperative fluid-attenuated inversion recovery MR imaging of cerebral gliomas: initial results

Fluid-attenuated inversion-recovery (FLAIR) imaging has shown to be a valua ble imaging modality in the assessment of intra-axial brain tumors; however , no data are available about the role of this technique in the clinically important postoperative stage. The purpose of this study was to evaluate th e diagnostic potential of FLAIR MR imaging in residual tumor after surgical resection of cerebral gliomas. Fifteen patients with residual cerebral gli omas were examined within the first 18 days after partial surgical resectio n of cerebral gliomas. The imaging protocol included T1-weighted spin echo, T2- and proton-density-weighted fast spin echo, and FLAIR imaging with ide ntical slice parameters. T1 and FLAIR were repeated after contrast media ap plication. Detection and delineation of residual tumor were the primary par ameters of the image analysis. Additionally, the influence of image artifac ts on the image interpretation was assessed. On FLAIR images residual signa l abnormalities at the border of the resection cavities were observed in al l patients, whereas T2- and T1-weighted images present residual abnormaliti es in 13 of 15 and 10 of 15 patients, respectively. The FLAIR imaging was f ound to be superior to conventional imaging sequences in the delineation of these changes and comparable to contrast enhanced T1-weighted imaging in t he delineation of residual enhancing lesions. Because of protein cell compo nents and blood byproducts within the resection cavity, FLAIR imaging was u nable to suppress the cerebrospinal fluid (CSF) in 4 patients. After the de composition of proteins and blood, CSF could again be completely suppressed and residual or recurrent tumors were clearly identified. Our preliminary study has shown that FLAIR may be a valuable diagnostic modality in the ear ly postoperative MR imaging after resection of cerebral gliomas due to its better delineation of residual pathologic signal at the border of the resec tion cavity. It should therefore be integrated into the early and/ or intra operative MR imaging protocol.