Friday, 15 February 2013

Looking Inside the Brain

This week, our Wellcome Trust Project Archivist, Louise, has been discovering more about one of the diagnosis methods used by neurosurgeon, Norman Dott:

As I become further involved with the cataloguing of Norman Dott’s case notes, I’m becoming more and more interested in the diagnosis methods that he used. Dott frequently employed three techniques to aid diagnoses: ventriculography, angiography and electroencephalography (EEG). I’m going to start by looking at ventriculography, because it is perhaps the most unfamiliar to modern ears.

Ventriculography was an x-ray technique used to diagnose suspected lesions in the brain or conditions such as meningitis or encephalitis (inflammation of the brain tissue). Developed by American neurosurgeon Walter Dandy (1886-1946) and used from 1900, ventriculography involved drilling burr-holes into the skull of the patient under local or general anaesthetic. Using a needle, cavities in the brain called ventricles were then tapped, removing the cerebrospinal fluid (CSF) that they hold. CSF cushions and protects the brain, reduces pressure by keeping the brain buoyant, takes away harmful substances and transports hormones and nutrients. Oxygen was then injected into the ventricles to replace CSF in order that any abnormalities could be seen more clearly on an x-ray.

In a 1930s’ case described by Dott as a ‘difficult diagnosis’ (but of ‘great interest’), a boy was operated on for hydrocephalus, or a build-up of CSF in the brain that causes dangerous pressure. However, whereas hydrocephalus was undoubtedly present, events after this initial surgery pointed to the possible presence of a tumour. By carrying out ventriculography, Dott was able to detect a glioma (a tumour arising from glial cells that support neurons in the central nervous system) and to operate immediately to remove it, saving the boy’s life.

Photograph of ventriculogram, 1936 (LHB1 CC/20/PR1/1215). The tube provided the patient with oxygen during the operative procedure.

Dott described the ventriculogram in this case as showing a ‘slightly distended third ventricle beautifully outlined’ and a ‘slightly distended lateral ventricle displaced to the right’. However, the ventriculogram also exposed another anomaly, which turned out to be the cyst of the glioma tumour, causing Dott and his team to operate straight away leading to the boy’s eventual recovery.

Photograph of ventriculogram on the same patient, 1936 (LHB1 CC/20/PR1/1215).

On account of its invasive nature, this form of ventriculography is no longer used in the diagnosis of brain disorders. Magnetic Resonance Imaging (MRI) scans and Computerised Tomography (CT) scanning are currently used in clinical practice, after being introduced during the 1970s.

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