INNOVATION AND CHANGE
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Despite the huge block pixels , 80x80 matrix , we could finally see the brain and we rejoiced . 1 Clearly these images were not even remotely comparable to the exquisite scans to which we are now accustomed , but for us they replaced pneumoencephalography . Hallelujah !
One has only to look at an empty pneumoencephalography chair to understand the horror of the procedure . It was introduced in 1919 by the eminent neurosurgeon Walter Dandy and was performed extensively until the late 1970s . 3 The method was to remove most of the cerebrospinal fluid via a lumbar puncture and replace it with air . The chair was open backed to allow access to the lumbar spine and multiple restraints were used to secure the patient who would be turned upside down several times during the procedure and placed face down , in a precisely monitored order to allow the air to fill the ventricles . The side effects were horrendous . 4 , 5 Just observing was sickening . And the resulting images were hardly informative . Unless the lesion resided at the interface of brain and ventricular / airspace surface , it had to be large enough to distort that interface by mass effect . I was intrepid enough to ask our neuroradiologist at the time if any patients had really benefitted from the procedure .
Godfrey Hounsfield ’ s original question when he came to EMI was , “ Could the unknown contents of a box be calculated by taking readings through the box ?” Later that year ( 1967 ) on vacation , he met a physician who complained to him about the drawbacks of conventional radiographic studies : a very lucky coincidence indeed . Although Godfrey Hounsfield is memorialized in Hounsfield units , the original CAT numbers , much of the theoretical work on which his prototype scanners depended was done by Allan Cormack in the 1950s and 60s . Cormack was a South African physicist who , in 1957 , moved to Boston where he joined the faculty at Tufts University . Hounsfield and Cormack were each recognized for their work and shared the 1979 Nobel Prize for Physiology or Medicine . 1
As the clinical significance of the head scan became clear , it would be just a matter of time and engineering until scan acquisition times were reduced to 20 seconds or less . It was generally accepted that if patients could hold their breath for periods of 20 seconds , diaphragmatic movement could be eliminated , and abdominal organs could be scanned . Robert Ledley , DDS , MS , a dentist on the faculty of Georgetown University , is generally recognized as having been the first in the U . S . to attempt to build a faster scanner . He founded Digital Information Science Corporation ( DISCO ). His unit was installed at Georgetown in 1974 , but subsequent production faltered . He soon sold his design to Pfizer . 1 By now multiple players were entering the field and the potential for whole body scanning was becoming a reality . I was Chief of Radiology at Louisville Veterans Administration Hospital in the 1980s when we received our first whole body scanner . This was to provide me with my second professional hallelujah moment . We would be able to see the pancreas in its entirety . Gone would be those inferential procedures which heretofore we had convinced ourselves we could aid our colleagues in diagnosing pancreatic disease . And just like good riddance to pneumoencephalography , I was ready to relegate double contrast hypotonic duodenography to the historical archive . 6
In the introduction to a paper on the role of hypotonic duodenography in the Medical Journal of Malaya , March 1971 , by Drs . Galanti and Wong , their opening sentence reads , “ The pancreas is supposed to be , more or less , the tomb of radiologists .” 7 My personal experience was the more rather than the less , although one of my fellow residents in the mid-1970s touted his expertise in the procedure . And he was good . Now we would all be on even ground .
Among the promotional materials that we received with our new body scanner was a carousel tray of clinical images . I offered the radiologists , the rotating residents and the two technologists who were being trained to run the scanner , an evening of CME at my home . Of course , refreshments would be provided . We gathered in the basement , projected the slides onto the wall and watched – initially in silence . I don ’ t pretend to remember who was most excited – perhaps the two technologists who , prior to that evening , felt they were stepping into the unknown . I had seen the pancreas , whole and entire , healthy and diseased . I knew we were moving into the future .
References :
1
Schulz R A , Stein J A , Pelc N J ,; How CT Happened : the early development of medical computed tomography . J Med Imaging ( Bellingham ) 2021 September ; 8 ( 5 ): 052110
2
Ambrose J , “ You never know what ’ s just around the next corner ,” Rivista Neuroradiol . 9 ( 4 ), 399-404 ( 1996 )
3
Fox W L ,; Dandy of Johns Hopkins . Williams and Wilkins , Baltimore , Maryland , 1984
4
White Y S et al .; Sequelae to Pneumoencephalography ; J Neurol Neurosurg Psychiatry . 1973 Feb .
5
Clark R A et al .; Pneumoencephalography . Comparison of complications in 100 pediatric and 100 adult cases ; Radiology . 1970 : PMID 5309773
6
Kreel L ,; Duodenography in Pancreatic Disease with Special Reference to “ Instant Duodenography .” Proc . Roy . Soc . Med . Volume 62 September 1969
7
Galanti A , Wong W K ,; The Role of Hypotonic Duodenography in the Diagnosis of Inflammatory and Neoplastic Lesions of the Head of the Pancreas ; The Medical Journal of Malaya . Vol XXV No . 3 March 1971
Dr . Amin is a retired diagnostic radiologist .
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