Isotope Encephalography Experience with 100 Cases

Abstract

The results of 100 brain scans are described. All the scans were made with 203Hg chlormerodrin using a standard technique. There was no selection of cases referred by neurologists and neurosurgeons, except that patients under the age of 18 were excluded. There were 53 positive scans, and all these patients appeared to have lesions, though not all these were confirmed histologically. There were 42 negative scans. Of these, 22 were probably truly negative. The remaining 20 were proved to be false—that is, these patients harboured tumours not demonstrated by the method. The causes of the false negatives are discussed and their reduced number in the future is foreshadowed. There were five equivocal scans. These showed some departure from the normal, but the appearances were not sufficiently clear-cut for definite diagnosis. Since a positive scan always denotes a lesion and the scanning process is painless and free from risk, it seems that, ideally, this investigation should be made before angiography and/or pneumography. But a negative scan in the face of positive clinical evidence of a mass always requires further investigation. The method is particularly valuable in the investigation of out-patients and of patients whose clinical picture hardly justifies submission to the more traumatic procedures which also carry some morbidity. Scanning has been a great help in the diagnosis of metastases, because the older-established neuroradiological procedures tend to show only the larger ones. The results in thee cases suggest that secondary deposits in the brain are more often multiple than was previously suggested by classical neuroradiological investigation, although well known by pathologists. Location of brain tumours by modern scanning techniques is accurate. In some cases the contour and topography allow a precise pathological diagnosis to be made. Unfortunately this is by no means always so, but it is hoped that still greater accuracy will be achieved by refining the technique. Isotope encephalography has clearly earned its place alongside other neuroradiological contrast methods of investigation. © 1965, British Medical Journal Publishing Group. All rights reserved.