Glial Neoplasms: Dynamic Contrast-enhanced T2*-weighted MR Imaging

TLDR

The study aimed to assess whether T2*-weighted echo-planar perfusion imaging using first-pass gadopentetate dimeglumine could correlate cerebral blood volume maps with astrocytoma grade and enhance stereotactic biopsy targeting. MR imaging of 29 patients employed a first-pass gadopentetate dimeglumine T2*-weighted echo-planar perfusion sequence, generating relative CBV color maps that guided stereotactic biopsy and were quantified using a nondiffusible tracer model relative to normal white matter. Maximum relative CBV was significantly higher in high-grade astrocytomas (mean 5.07) than in low-grade tumors (mean 1.44), with a statistically significant difference (P < .001), demonstrating that echo-planar perfusion imaging aids preoperative grading and biopsy targeting.

Abstract

PURPOSE: To evaluate the role of T2*-weighted echo-planar perfusion imaging by using a first-pass gadopentetate dimeglumine technique to determine the association of magnetic resonance (MR) imaging–derived cerebral blood volume (CBV) maps with histopathologic grading of astrocytomas and to improve the accuracy of targeting of stereotactic biopsy. MATERIALS AND METHODS: MR imaging was performed in 29 patients by using a first-pass gadopentetate dimeglumine T2*-weighted echo-planar perfusion sequence followed by conventional imaging. The perfusion data were processed to obtain a color map of relative regional CBV. This information formed the basis for targeting the stereotactic biopsy. Relative CBV values were computed with a nondiffusible tracer model. The relative CBV of lesions was expressed as a percentage of the relative CBV of normal white matter. The maximum relative CBV of each lesion was correlated with the histopathologic grading of astrocytomas obtained from samples from stereotactic biopsy or volumetric resection. RESULTS: The maximum relative CBV in high-grade astrocytomas (n = 26) varied from 1.73 to 13.7, with a mean of 5.07 ± 2.79 (± SD), and in the low-grade cohort (n = 3) varied from 0.92 to 2.19, with a mean of 1.44 ± 0.68. This difference in relative CBV was statistically significant (P < .001; Student t test). CONCLUSION: Echo-planar perfusion imaging is useful in the preoperative assessment of tumor grade and in providing diagnostic information not available with conventional MR imaging. The areas of perfusion abnormality are invaluable in the precise targeting of the stereotactic biopsy.