Imaging-based stereotaxic serial biopsies in untreated intracranial glial neoplasms

Abstract

Forty patients with previously untreated intracranial glial neoplasms underwent stereotaxic serial biopsies assisted by computerized tomography (CT) and magnetic resonance imaging (MRI). Tumor volumes defined by computer reconstruction of contrast enhancement and low-attenuation boundaries on CT and T1 and T2 prolongation on MRI revealed that tumor volumes defined by T2-weighted MRI scans were larger than those defined by low-attenuation or contrast enhancement on CT scans. Histological analysis of 195 biopsy specimens obtained from various locations within the volumes defined by CT and MRI revealed that: contrast enhancement most often corresponded to tumor tissue without intervening parenchyma; hypodensity corresponded to parenchyma infiltrated by isolated tumor cells or in some instances to tumor tissue in low-grade gliomas or to simple edema; and isolated tumor cell infiltration extended at least as far as T2 prolongation on magnetic resonance images. This information may be useful in planning surgical procedures and radiation therapy in patients with intracranial glial neoplasms.

Virtual brain tumours (gliomas) enhance the reality of medical imaging and highlight inadequacies of current therapy

“…Confirmation of this analogy has been provided by Silbergeld and Chicoine (1997), who were able to grow in culture glioma cells from brain tissue that was histologically normal 4 cm distal to the gross edge of the tumour. Furthermore, Kelly et al (1987) were able to show in at least half of their patients that 'isolated tumour cells' could be identified microscopically in biopsies distal to even the most sensitive MRI marker. Previous reports (Burgess et al, 1997) estimated the enhanced CT-delineated tumour boundary to correspond to a tumour cell concentration of about 8000 cells mm 73 .…”

Pseudoprogression, radionecrosis, inflammation or true tumor progression? challenges associated with glioblastoma response assessment in an evolving therapeutic landscape

“…Following contrast agent extravasation, tumor regions become bright on T1-weighted images due to T1 shortening. Studies have confirmed that areas of contrast enhancement often contain the most aggressive portions of the tumor [4], suggesting the presence of contrast-enhancement reflective of increased vascular permeability may be a valuable surrogate for more aggressive brain tumor behavior. In 1990, Macdonald et al [5] introduced the first response criteria specifically for neuro-oncology by specifying the definition of radiographic response using quantitative bidirectional measurements and accounting for corticosteroid use and neurological status.…”

Patterns of Recurrence Analysis in Newly Diagnosed Glioblastoma Multiforme After Three-Dimensional Conformal Radiation Therapy With Respect to Pre–Radiation Therapy Magnetic Resonance Spectroscopic Findings

“…Serial biopsy studies show tumor cells more than 3 cm from the contrast enhancing (CE) region [13]; in addition, some tumors are not contrast-enhancing, and the T2 hyperintensity (T2h) may not distinguish tumor from edema, or normal appearing brain tissue beyond T2h might harbor tumor cells. Previous studies have shown that threedimensional (3D) magnetic resonance spectroscopic imaging (MRSI) is valuable for mapping the spatial extent of brain tumors and this technique is suggested as an adjunct to MRI in delineating the target for radiation therapy in high-grade gliomas (HGG) [14,15].…”