M. D. F. Deck

Radiation necrosis after treatment of solitary intracranial metastases

During the period from July 1977 to June 1980, 75 patients underwent the surgical excision of solitary brain metastases, and 61 of these patients received whole brain radiation. Three patients developed chronic radiation necrosis. In the 3 patients with necrosis, computed tomography suggested recurrent tumor; the histological diagnosis of necrosis only was obtained at operation in 2 of these patients and by autopsy in the third. Radiation damage resulted in the death of 1 patient, a chronic vegetative state in another, and severe neurological deficit in the third. An additional 4 patients had neurological complications probably related to radiation therapy. As the survival of such patients is prolonged by aggressive treatment, the incidence of radiation-induced complications is likely to increase. The optimal dose of radiation necessary to destroy microscopic foci of tumor after the surgical resection of a single brain metastasis is unknown. Because of the significant incidence of damage after radiation as currently delivered, studies using graded, lower doses are indicated.

Magnetic Resonance Imaging in the Evaluation of Leukocoria

Leukocoria is an important clinical sign in ophthalmology. Conditions producing this white pupillary reflex must be differentiated from retinoblastoma to insure appropriate and timely treatment. Auxiliary diagnostic testing has been helpful in securing a clinical diagnosis. A new diagnostic modality, magnetic resonance imaging, provides similar morphologic information with the additional potential for biochemical characterization. A series consisting of 14 patients presenting with leukocoria as a result of retinoblastoma and simulating conditions was examined. The magnetic resonance imaging findings are discussed.

Partial Volume Summation: A Simple Approach to Ventricular Volume Determination from CT

The accurate determination of ventricular volume from computed tomography (CT) is not a trivial problem. The direct approach of measuring the area within a visually determined boundary or contour level and multiplying by the nominal slice thickness may be subject to large errors because such boundaries are not, in general, well defined. When the ventricles are filled with a high-contrast material such as metrizamide, we may use the technique of ‘partial volume summation,’ a simple but accurate, clinically applicable method which may be performed on a standard DeltaScan-50 or similar system.

Intra-arterial BCNU in the treatment of metastatic brain tumors

Thirty-one patients with metastatic brain tumors that either failed to respond or recurred after conventional therapy were treated by intra-arterial infusion of 100 mg/m2 of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) into either a carotid or vertebral artery. Five patients (three with lung cancer, one with breast cancer and one with melanoma) had a partial response of the tumor(s) in the distribution of the injected artery. In two patients, brain metastases not in the distribution of the injected artery enlarged, while the tumors perfused by the injected artery responded. In one of these patients, subsequent infusion of BCNU to the enlarging tumor resulted in a partial response. Among responders, the median survival following onset of BCNU was 17 weeks. One patient remains alive and well at 30 weeks. No permanent neurological, retinal or systemic toxicity was observed.

The effects of CT drift on xenon/CT measurement of regional cerebral blood flow

A systematic increase in computed tomography (CT) number of approximately 0.13 Hounsfield unit per scan (HU/scan) was observed when serial DeltaScan 2020 CT scans of a uniform water phantom were equally spaced at 0.5, 1.0, or 2.0 min and a shaped aluminum beam-hardening filter was employed. Much smaller drifts (less than 0.06 HU/scan) were observed with flat aluminum or shaped beryllium oxide filters. This machine drift, which was not associated with a rise in water phantom temperature and did not consistently correlate with estimated x-ray tube heat, could result in a significant overestimation of regional cerebral blood flow (rCBF) for a xenon/CT rCBF protocol involving 5-7 sequential scans obtained at 1-min interscan intervals.

Metronidazole as a radiation enhancer in the treatment of metastatic epidural spinal cord compression

Epidural spinal cord compression is a painful and often disabling nervous system complication of systemic cancer. Occurring clinically about half as often as metastatic brain tumors, the disorder, if untreated, usually leads to paraplegia, considerably diminishing the quality of life in a patient suffering f rom cancer. The best treatment of epidural spinal cord compression remains controversial, with some advocating surgical decompression and others radiation therapy as the initial treatment. Whatever the treatment chosen, however, the outcome is poor, since in most series only about half of the patients either maintain or regain ambulat ion( l , 2). Par t of the poor outcome is due to a delay in diagnosis, but part may also be the inadequacy of t reatment in producing rapid reversal of the compression. In an attempt to improve the relatively poor outcome of radiation therapy in treating spinal cord compression, we undertook to study the role of a radiation enhancer, metronidazole (a 5nitroimidazole which is commercially available) in a prospective randomized study of patients with newly diagnosed metastatic epidural spinal cord compression.

Metronidazole in the treatment of metastatic brain tumors

SummaryWe measured the effect of the radiation enhancer metronidazole on patients with metastatic brain tumors undergoing radiation therapy (RT) in a randomized controlled study. Metronidazole was given in a dose of 6 g/m2 4 h before each of the first 3 doses of RT to the whole-brain. A total of 3000 rad was delivered in 6 doses. Patients were followed by serial neurological examinations and CT scans. The metronidazole group did not differ from the control group when measured in terms of survival, clinical improvement or improvement on CT scan, whether measured 2 months or 6 months following treatment. Nausea and vomiting was a significant side effect, preventing about 10% of patients from completing the treatment. Metronidazole appears to have no substantial radiation enhancing effect on metastatic brain tumors.

Brain Tumors Presenting as Small Calcified Lesions on Computerized Tomography

3 children were found to have small focal calcifications on computerized tomography. These lesions ultimately proved to be malignant gliomas in 2 children, and a mixed glioma in the third. Focal calcification on CT scans may pose a diagnostic dilemma for the clinician, and these patients should be carefully followed as possible early brain tumors.