The EMI scanner and its application to clinical diagnosis

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The concept of computer application to diagnosis by roentgenography has been studied by many investigators; however, the ultimate development and application of the process to clinical medicine is mainly the work of Ambrose and Hounsfield and EMI Ltd.1, 2 The basic concept of utilizing digital computers to measure variations in x-ray absorption was tested by Ambrose, neuro-radiologist at Atkinson-Morley’s Hospital, and was initially reported to the British Institute of Radiology in April 1972.1, 3

The EMI scanner has made it possible to analyze the depths of the brain without danger or discomfort to the patient, and to diagnose brain tumors, hydrocephalus, cerebral atrophy, and cerebral infarcts without contrast agents or radio-active material. This ingenious application of the computer permits analysis of the variations in x-ray absorption through multiple sections of brain substance. The picture produced displays the structure and configuration of the soft tissues of the brain. The unit installed at the Cleveland Clinic in January 1974 has been used in 450 cases. In general, the early experience here parallels that in other centers,3–5 and it is apparent that computerized axial tomography (CAT) will have a significant impact on the “usual” approach to the diagnosis and treatment of neurologic disorders.


To describe the intricate computer technology and the mechanical structures of the unit is not the purpose of this report; a detailed description has been published.2, 6–9 However, a basic understanding of the mechanisms involved is necessary to appreciate the extraordinary capabilities of the scanner.

The EMI. . .



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