Showing papers by "Peter C. Burger published in 1989"

Radiation therapy treatment planning in supratentorial glioblastoma multiforme: An analysis based on post mortem topographic anatomy with ct correlations

Abstract: In a previous study of the brains of 15 adults with glioblastoma multiforme who received minimal or no radiotherapy we determined the topographic distribution of tumor cells. All 15 brains had been fixed and then cut in the coronal or horizontal plane. The distribution of neoplastic cells was determined and entered onto tracings of the whole mount histologic sections. The last CT scans obtained prior to death of 11 of the patients were reviewed independently by a neuroradiologist who traced, on the CT scans, the outer edge of both the contrast-enhancing area and the peritumoral low density “edema”. Presented with the neuroradiologist's assessment of the contrast enhancing rim of tumor and of the “edema”, a radiotherapist and a radiation dosimetrist, in the present study, prepared treatment plans for a 6 MeV linear accelerator. In 9 of the 11 cases in which immediately antemortum CT scans were available, radiation treatment of the contrast enhancing area alone with a 1 cm margin would have missed portions of the histologically identified tumor. Treatment of the contrast enhancing area along with the peritumoral “edema”, with a 1 cm margin, would have covered histologically identified tumor in six of the 11 cases. Treatment of the contrast enhancing area, all “edema”, and a 3 cm margin around the “edema” would have covered histologically identified tumor in all cases. Tumors tended to track along nerve pathways. In those lesions near the midline it was common for tumor to cross the corpus callosum. We conclude that radiotherapy with fields designed to treat the contrast enhancing region alone or this region plus “edema” with a tight margin will frequently miss tumor which can be histologically identified by our technique.

Cytologic composition of the untreated glioblastoma with implications for evaluation of needle biopsies

Abstract: To study the progression of astrocytic neoplasms and to provide practical information about the topography of the glioblastoma multiforme, the distribution of eight defined cell types was mapped from whole brain sections of 18 glioblastomas studied postmortem. Based on the densities and topographic distributions of well-differentiated and anaplastic cells, three principal categories of neoplasms were defined. In one group of three cases, multifocal glioblastomas appeared to be emerging in the background of a better differentiated, and presumably precursory, astrocytic neoplasm. In another group of nine cases, the neoplasms were more intimate mixtures of well and poorly differentiated cells. The third group of five cases was composed of neoplasms that were largely undifferentiated without a component of better differentiated cells. The study suggests that progression from a better differentiated neoplasm to one composed largely of undifferentiated cells is common in the fibrillary astrocytic neoplasms. Although some glioblastomas appear largely undifferentiated and consistent with the de novo appearance of overt malignancy, the size of these neoplasms and the patterns of necrosis leave open the possibility that a preexisting better differentiated neoplasm had been obliterated by necrosis and the overgrowth of the anaplastic component. The potential topographic variation of cellular constituency in a glioblastoma underscores the care that must be exercised in utilization of the needle biopsy technique in the diagnosis and grading of astrocytic neoplasms.

Dilated Virchow-Robin spaces in cryptococcal meningitis associated with AIDS: CT and MR findings.

Abstract: We present two patients with AIDS complicated by cryptococcal meningitis who displayed focal hypodense nonenhancing lesions in CT in the basal ganglia with corresponding areas of increased T2 and decreased T1 signal on magnetic resonance (MR). These lesions corresponded precisely to the distribution of the perforating arteries. Review of pathological specimens showed these lesions to be small cystic collections of cryptococcal organisms in the perivascular spaces of the arteries with minimal or no inflammatory reaction. The cryptococcal organisms spread from the basal cisterns through the Virchow-Robin spaces, dilating these spaces, to ultimately propagate in the basal ganglia, internal capsule, thalamus, and brain stem. Such lesions have been described as characteristic for cryptococcosis in the pathology literature before the AIDS epidemic, but the radiological manifestations have not been reported previously. The changes appear characteristic for cryptococcosis, which generally incites no host response in the form of perifocal edema or enhancement. These findings in a young adult, with otherwise normal CT or MR scans, may be the first indication that the patient has AIDS. The T2-weighted image sequences are more sensitive in the detection of these lesions when compared to CT or T1-weighted MR images.

The Grading of Astrocytomas and Oligodendrogliomas

Abstract: The grading of astrocytomas and oligodendrogliomas persists as a controversial subject that is not likely to resolve spontaneously into a consensus on a single grading system, universally applied. Such an unanimity seems especially unlikely since many of the present histologic classifications work, that is, they assign patients to groups whose survival curves are better or worse than patients with lower or higher histologic grades, respectively. Nevertheless, some common, or at least widely used, system is desirable as is apparent in the standardizing attempts of the World Health Organization Blue Book in its original Zulch (1979), and soon- to-be-revised form.

Sonographic characteristics of small cerebral blood vessels - an in vivo and postmortem study

Abstract: The ultrasound appearance of small cerebral blood vessels was investigated with in vivo and postmortem sonography. Linear echoes corresponding in distribution to small branches of major cerebral blood vessels, particularly deep medullary veins, were seen during cranial sonography of living neonates, neonatal postmortem brains, and adult postmortem brains following intravascular injection of a barium sulfate-gelatin suspension. Ease of visualization of the echoes was angle dependent, a phenomenon termed anisotropy. When imaged in cross-section, these reflectors appeared as tiny, closely spaced dots, demonstrating their tubular nature. Additionally, the barium-injected adult postmortem specimens were studied by computed tomography and plain-film radiography, enabling correlation between radiography and sonography. This study demonstrates that small branches of the major intracranial blood vessels can be imaged as linear echoes and closely spaced dots by high-resolution sonography. It is important to recognize the vascular origin of these echoes to avoid the pitfall of misinterpreting them as originating from pathologic processes such as periventricular leukomalacia.