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The EMI scanner.

  • Ambrose, James E.
  • Videos
  • Online

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Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
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About this work


Dr James Ambrose enthusiastically introduces the subject of EMI brain scanning, a relatively new technology when this programme was made - now referred to as computed tomography or CT scanning. He begins by describing how the EMI scanner is a far better diagnostic tool than other current methods for looking at the brain: "it requires no great stretch of the imagination to see that what we have required for a long time now is a system which would enable us to look at the structure of the brain without causing the patient fear or discomfort." For the rest of the lecture, Ambrose gives a history of the discovery of EMI scanning, practical demonstrations of the scanner and case studies leading to diagnoses. He uses scans, graphs and diagrams to illustrate his points.


London : University of London Audio-Visual Centre, 1975.

Physical description

1 encoded moving image (34.43 min.) : sound, black and white.




Copyright note

University of London

Terms of use

Creative Commons Attribution-Non-Commercial 2.0 UK: England & Wales

Language note

In English

Creator/production credits

Presented by Dr James Ambrose, Radiologist, Atkinson Morley's Hospital. Produced by David Clark. Made for British Postgraduate Medical Federation. Made by University of London Audio-Visual Centre.


This video is one of around 310 titles, originally broadcast on Channel 7 of the ILEA closed-circuit television network, given to Wellcome Trust from the University of London Audio-Visual Centre shortly after it closed in the late 1980s. Although some of these programmes might now seem rather out-dated, they probably represent the largest and most diversified body of medical video produced in any British university at this time, and give a comprehensive and fascinating view of the state of medical and surgical research and practice in the 1970s and 1980s, thus constituting a contemporary medical-historical archive of great interest. The lectures mostly take place in a small and intimate studio setting and are often face-to-face. The lecturers use a wide variety of resources to illustrate their points, including film clips, slides, graphs, animated diagrams, charts and tables as well as 3-dimensional models and display boards with movable pieces. Some of the lecturers are telegenic while some are clearly less comfortable about being recorded; all are experts in their field and show great enthusiasm to share both the latest research and the historical context of their specialist areas.


Segment 1 Ambrose begins by running through a list of examples of what is likely to happen to a patient being investigated in hospital for a disease of the central nervous system; he uses a hypothetical case of a patient with a tumour in the right hemisphere. Ambrose shows a table listing the various different diagnostic techniques for defining tumour types. These include: straight skull radiography, radio-nuclide scanning, ultrasound, cerebral angiography and cerebral pneumography. These are more or less invasive but Ambrose points out that the last two are particularly troubling for patients. He then shows examples from each of the techniques listed and explains their pros and cons. He ends by dramatically pointing to an EMI scan and describing it as a way to change the whole system of brain imaging. Time start: 00:00:00:00 Time end: 00:05:08:00 Length: 00:05:08:00
Segment 2 Ambrose explains, using illustrations, how a different method of scanning to those mentioned above might work. He then gives the history of the discovery of such a method - referring to the work of neurologist WH Oldendorf, AM Cormac and DE Kuhl, all of whom came close to discovering a method like EMI scanning. A short film is then shown of a patient having an EMI scan, then Ambrose talks us through the computer reading of the scan results. Time start: 00:05:08:00 Time end: 00:10:22:00 Length: 00:05:14:00
Segment 3 We hear now about how the EMI scanner can measure different densities of brain tissue, thus enabling tumorous areas in soft tissue to become apparent to the clinician. A further short film shows a woman having an EMI scan and Ambrose describes how the machinery works. We then see a sequence of slides of EMI brain scans, Ambrose discusses the appearance of each, pointing out anatomical features of interest. Time start: 00:10:22:00 Time end: 00:15:20:00 Length: 00:04:58:00
Segment 4 Ambrose moves on to discuss the kind of features that might be seen in an abnormal brain scan. He describes how abnormal structures in the brain can be according to size, shape and position, then changes in tissue density are sought. He defines 3 types of tissue density produced by: lesions with a higher density than normal, lesions with a lower density than normal and lesions with the same density as normal tissue. He shows a series of case studies detailing a wide variety of lesions in the brain in which tissue density is higher than that of normal surrounding tissue. In each case, Ambrose explains in detail how the EMI scan can be read accurately. This is particularly important as some surgical interventions can be made based on the EMI scan evidence - for instance, if a blood clot can be accurately located by imaging, surgery can be performed to remove it quickly and effectively. Time start: 00:15:20:00 Time end: 00:20:58:00 Length: 00:05:38:00
Segment 5 Ambrose moves on to show EMI scans of cases with low density lesions in the brain. In each case he explains clearly what the scan shows and how a diagnosis can be made from the visual information given. Cases include: neoplasms, infections, infarctions, cyst formation or demyelinating processes such as multiple sclerosis. Time start: 00:20:58:00 Time end: 00:25:19:00 Length: 00:04:21:00
Segment 6 Ambrose now shows EMI scans of brain lesions with the same tissue density as normal surrounding tissue. In each case he explains clearly what the scan shows and how a diagnosis can be made from the visual information given. Cases include: meningioma, small metastatic tumours, oedema and absesses. In these cases a contrast dye injected into the blood stream can be helpful to define their mass. Time start: 00:25:19:00 Time end: 00:30:02:20 Length: 00:04:43:00
Segment 7 Ambrose describes how EMI scanning can help to identify some of the more illusive lesions of the brain such as tumours in and around the pituitary fossa. More detailed scanning techniques can also show the optic nerve and surrounding tissues - Ambrose shows a case in which there is a large tumour in the outer quadrant of the left eye. Ambrose sums up his lecture by noting that the EMI scanner is really a prototype, a first generation scanner and that the future will see advancements in its speed, accuracy and picture resolution. He looks forward to seeing what modern technology will have to offer in future years. Time start: 00:30:02:20 Time end: 00:34:43:03 Length: 00:04:41:08


  • English

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