The Significance of Lack of MR Contrast Enhancement of Supratentorial Brain Tumors in Adults: Histopathological Evaluation of a Series

Preoperative Grading of Presumptive Low-Grade Astrocytomas on MR Imaging: Diagnostic Value of Minimum Apparent Diffusion Coefficient

“…These are due to astrocytomas often having great histopathologic heterogeneity with focal areas that contain more malignant features interspersed among regions with a benign appearance. 15,17 Accurate grading of gliomas is extremely important because the therapeutic approach and prognosis differ considerably according to tumor grade. A diffuse WHO grade II astrocytoma is the most benign grade for which, typically, the survival exceeds 5 years and the postoperative survival usually ranges from 3 to 10 years.…”

Role of Perfusion CT in Glioma Grading and Comparison with Conventional MR Imaging Features

“…17 Contrast enhancement on MR imaging depicts areas of breakdown of blood-brain barrier, 28 which is often associated with higher tumor grade; however, contrast enhancement is not always accurate in predicting the tumor grade. 8,[29][30][31][32] Even in the high-grade gliomas with pathologic contrast enhancement, the enhancement may not reflect the areas of neovascularity and angiogenesis. 33,34 Thus radiologic grading of tumors with conventional MR imaging is not always accurate, with sensitivity in identifying high-grade gliomas ranging from 55.1% to 83.3% in various studies 8,14,17,18,31 and 85.7% in our study.…”

Diffusion Tensor MR Imaging of Cerebral Gliomas: Evaluating Fractional Anisotropy Characteristics

“…[3][4][5] Therefore, the presence or absence of cystic change, hemorrhage, edema, and contrast enhancement is not always specific for discriminating low-grade from high-grade tumors.…”