THE ULTRASONIC BOOM by
Ian Donald, Mi),Queen Mother’s Hospital Glasgow , Scotland
This speech was given by Dr. Ian Donald at the opening session o f the World Federation of‘llltrasound in Medicine and’Biology o n August 3rd in San Francisco. Dr. Ian Donald, a guest of AIUM and a guest of the conference, who has been an outstanding figure in the development of diagnostic ultrasound in England, was the speaker. Dr. Donald has given particular attention to the applications o f diagnostic ultrasound in the field o f obstetrics and gynecology. Because o f its general interest t o all in the field o f diagnostic ultrasound, Dr. Brown and I decided to publish the paper both in Reflections and in the Journal of Clinical UltrdSound.
Medical sonar has quite suddenly grown up and come of age; in fact, its growth spurt within the last few years has been almost explosive. This is in marked contrast with its youthful development which was, to say the least of it, somewhat retarded. Its history is very different from that of X radiology, which burst upon the world with eclat following Roentgen’s humble publication in 1895, such that within a few years in England the Roentgen Society had already been formed. Dreadful irradiation casualties followed in its wake, and I am old enough to recollect the sheer horror of some of the injuries inflicted, especially on the pioneers in that exciting field. My own unmentionable disregard for precautions as a young man when handling radium and xrays would horrify the physicist of today. Sonar, a t least, has exacted no such demonstrable toll, but vigilance must remain both now and in the future (1,2) even though we fully recognize that we are dealing only with mechanical energies rather than those derived from the electromagnetic spectrum and that consequently the possibility of delayed sinister effects can reasonably be ignored. To quote Denis White at the Rotterdam conference, “so long as this energy is kept below the level of intensity that would disrupt the forces that bind the tissues together, no tissue damage is likely to occur. If this level should be exceeded, then all the tissue VOLUME 4, NUMBER 5
in the supra-threshold regon would be affected in contrast with the scattered atoms affected by Xradiation. Thus, theoretically at least, small intensities of ultrasonic energy are harmless; small intensities of Xradiation are always harmful, albeit it is not grossly so” (3). In recognizing the “ultrasonic boom” at present with us, we must acknowledge the genius of those to whom the subject owes so much. I refer particularly to the late Douglas Howry, whom I had the privilege of meeting both in London and in Pittsburgh, Pennsylvania, and whose enthusiasm was totally infectious (4-6). Also Wild, whose exuberance was by no means misplaced (7,8). Notable physicists and engineers have been mainly responsible for the exploitation of Firestone’s original work on metals (9) and although it might be invidious to pick out only a few, I personally cannot help acknowledging Reid in the United States and Tom Brown in Scotland as among the really inventive geniuses, nor can I fail to acknowledge the help of Tom Duggan also in Scotland for his contribution of superimposing electronic cursors which have made accurate measurement one of our mainstays in producing worthwhile results (10). The exploitation of the ultrasonic Doppler effect (11, 12) is something about which I was guilty of being skeptical, and in fact I can remember so advising Carlin: upon whose textbook 323
on the physics of ultrasound I had so greatly relied myself (13). Fortunately, my advice was ignored and the subject went ahead with today’s brilliant resdts. To Effert and his colleagues in Germany ( 1 4 ) , I and many others owe a debt for introducing us to the first attempts to make use of time-motion scanning which has proved so profitable in cardiology. It is necessary, however, for some physician intellectually orientated towards the physics of ultrasound to integrate the whole subject, and here I think we must all acknowledge the wonderful achievements of Joseph Holmes whose energy, enthusiasm, and generosity have sustained not only him but us as well over all these years, ever since I first met him in 1963. I think Joe Holmes has done more than anyone to pull us all together from our several pathways. It will be noted that the above were not simply drawn from the ranks of clinicians, nor radiologists, nor physicists, nor any other type of technologist. The present state of the ultrasonic art has grown out of the corporate effort of workers with many different backgrounds and long may it remain so. I shall have more to say on the subject of “market cornering” presently. It can be seen that the technical brilliance that has emerged in the last 10 years cannot be adequately itemized and if momentum in terms of physics is represented by the product of mass x velocity and if force can be described in terms of acceleration, then the mind boggles at the scale of advances that lie immediately ahead. In our own case it was not an abstract academic interest that motivated us. It was the sheer, stark, clinical reality of a difficult differential diagnosis in the subject of the grossly distended abdomen which at that time interested me and which clearly saved a woman’s life by diagnosing with Ascan sonar, even in those far off days, a truly gigantic ovarian cyst which was perfectly benign. Her state had been wrongly attributed, not without reason, to acute distension from malignant portal obstruction, secondary to a misdiagnosed carcinoma of stomach, thanks to a radiological artifact. Her plight was pitiable as she lay vomiting blood and dying and was in such marked contrast to her instant recovery following my removal of this tumor that we became inevitably committed, as did my engineering friends from whom I borrowed the ultrasonic equipment. From that moment morally there could be no going back. After all, what price a woman’s life? Thereafter one thing led to another which led to another, 324
and the great drive to exploit a new diagnostic technique got under way (15 , 16). BREAKTHROUGH EVENTS
To those of us who have worked in the ultrasonic field for more than 20 years, certain events have in their several ways produced a breakthrough. 1. The conversion of Ascan to Bscan, to be followed later by combining the two and adding time-motion scanning. 2. The development of contact scanning(l7, 18).We have always regarded this as desirable in the interests of convenience, maneuverability, and patient acceptability. The subject, however, was not without its difficulties, and we are well aware of the high quality of pictures (19,20) which can be obtained through the medium of water tanks. In the first instance compound B scanning was necessary in order to reveal the anatomical outline studies of structures, whether of tumors or their relationship to neighboring viscera, or fetal parts, particularly the head dimensions and also for placental localization. Our dependence on specular reflection has lessened with further refinement and the information yield has increased without the resolution losses which are inherent in compounding. 3. The exploitation of the ultrasonic Doppler effect. This had an immediate success in recording the fetal heart, even in fairly early pregnancy, but is likely to prove increasingly useful in bloodflow studies. 4. The development of the full bladder technique which not only incorporates all the advantages of a built-in water tank but allows ultrasonic access to structures deep within the pelvis, so that extensive studies, for example, of very early pregnancy and fetal development can now be made i(21, 22). 5. Gray-scale imaging. Whether achieved by highly developed and sophisticated logarithmic compression amplifiers (23-26) or by the principle of scan conversiQn (27, 28), there is no doubt that a whole new diagnostic range in the study of tissue structure has been opened up with this new technique. It is particularly important in such diverse subjects as hepatic diseases, including malignant metastases and placental studies. The useful point about scan conversion techniques is that even inexperienced operators can still produce good pictures even though guilty of overwriting, thanks t o the builtin peak value memory. Where degradation in a gray scale picture occurs, especially in obstetrics, JOURNAL OF CLINICAL ULTRASOUND
FIGURE 1. Blighted o v u m in very early pregnancy, Embryonic sac evacuated, Contained only a small disorganized fetal pole.
FIGURE 2. Normal early pregnancy. N o t e fetus (arrow) and placenta differentiating at fundus. Black on w h i t e picture.
touch ultrasonics with a bargepole. He had now changed course to a 180" reciprocal, rather like what happened on the road t o Damascus. 2. Opportunities Wantonly Missed. It was constantly galling t o be greeted by a colleague who remembered a patient who might have yielded interesting ultr+onic results, and on our immediate inquiry as to her whereabouts to be told regretfully that she had either died or been dismissed home and could not be recalled. Louis Pasteur was indeed right when he talked about the chance observation and the prepared mind. 2. The Stage of Overacceptance. Now the impossible was expected of us. The most bizarre STAGES IN DEVELOPMENT and unexpected tumors were expected t o be immediately diagnosed, and in self protection I, like others of my generation, have lived through five stages which we can easily identify, one was reduced to explaining to an everincreasing extent the limitations of existing not without a trace of cynicism. 1. Disbelief. If it had not been for the gener- sonar techniques. This stage of overacceptance was also the ous help of friends in the engineering world, we might well have foundered here. The attitude of stage of our greatest mistakes from which we one's colleagues was on the whole good-natured learned so much. Throughout, mistakes have such as might be shown towards the eccentrici- proved more instructive than successes. It is ties of a fairly harmless lunatic. When it came to a hard philosophy but one which must be acraising money, however, the situation was cepted. Some of them have been simple enough, somewhat less favorable. I can still recall with for example, the twins which did not materialannoyance the frivolous comment of one of ize, or the cheerfully monitored pregnancy my alleged friends from the rival city of Edin- which finally ended in the wrong number of burgh who returned home full of my wife's fetuses. Our mistakes in diagnosing an abnormal wine and excellent cuisine only to announce to blighted pregnancy have been gradually elimia hilarious group of students that in Glasgow we nated (Fig. l), especially with studies of the needed a machine, then costing about $10,000, fetal heart from the sixth week of amenorrhea to diagnose an ovarian cyst which he with his onwards (Figs. 2, 3), but on the subject of fetal God-given clinical acumen could diagnose with a abnormality we have much yet to learn (Fig. 4). The prenatal diagnosis of fetal handicap is twopenny glove. The mistakes of which we were guilty at that time taxed both my authority and now occupying an ever-increasing role in modern the forbearance of those who had sought my obstetrics. If I with 38 years of clinical experidiagnostic help. An eminent physicist was once ence can make mistakes, how much more likely heard to apprise a personage in authority not to are they to be made by the less knowledgeable; it is probably due to fetal movement, the extent of which can only be satisfactorily revealed by the more newly developed methods of real time scanning. 6. Real time scanning. Until recently real time scanning systems have been largely thwarted by poor resolution and intolerable flicker, faults inherent in design using single transducers. The more modern employment of multielement transducer arrays, sequentially fired, however, now produces a real, live picture of what is going on while it is going on. A new dynamic element is thus introduced into diagnosis. (29, 30).
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FIGURE 3. Fetal heart of same case as Figure 2 recorded a f e w days later. Maturity 8-9 weeks.
FIGURE 5. Postnatal ultrasonic renogram i n severe case of systemic lupus erythromatosis involving kidneys. Transverse dorsal view. N o t e small kidneys w i t h narrowed parenchyma.
tions of men are vying with each other to secure a place in the ultrasonic sun. It goes without saying that the last t o climb on the bandwagon will be the first to jump off at the first sign of trouble or danger. This would .be all acceptable enough if it did not carry with it attempts to corner the market. WHOSE RESPONSIBILITY?
FIGURE 4. Enormous cystic hygroma of neck; wrongly diagnosed as omphalocele. No placenta posteriorly.
and I can say in all clinical humility that if there is any diagnostic mistake which I have not yet made, there is still time for me to make it. Nevertheless, when bad sonar is combined with bad clinical diagnosis the results can be truly disastrous and reflect discredit on the whole subject. With the latest gray scale imaging techniques I think, however, that we have now reached somewhere very near the ultimate in what can be achieved with two dimensional scanning with single probe machines (Fig. 5). 4. The Stage of Justification. The mounting expenses could assuredly by justified by results, certainly in obstetrics. Sonar has indeed transformed the practice of obstetrics in innumerable directions, and we have reached the stage where most of us who have reaped the benefit would be very loath to continue to practice without it. Sonar has in no way replaced clinical judgment but it has certainly improved it. 5. The Bandwagon Stage. This is a new form of overacceptance in which all sorts and condi326
The day is fast approaching when sonar should be regarded as a discipline in its own right. Of course radiologists must understand it, and the Royal College of Radiologists has made a knowledge of the subject a part of its requirements for the Fellowship Examination in England. Of course, obstetricians should know and understand it, and in fact a couple of years ago t h e first question in the paper for the M.R.C.O.G. Diploma was on the subject of sonar. Of course, cardiologists should know the subject as much as they are at present expected t o understand electrocardiography. I would disagree most strongly with the view, which I have already encountered, that sonar should be treated as an integral part of radiology only. There is already great danger of a conflict of interests of established departments. There must be no market cornering and no confrontation between departmental and parochial interests. Nothing could be more detrimental to further advance. The danger has already been foreseen in England by the Royal College of Obstetricians & Gynecologists and the Royal College of Radiologists, numerically still the most important groups, although cardiologists, urologists, and i’nternists are likely soon to enter the lists before it is too late. JOURNAL OF CLINICAL ULTRASOUND
On behalf of thes two Royal Colleges some very wideranging discussions have taken place in which I was involved. The recommendations include the setting up of a standing Liaison Committee to keep the possibility of hazard under review and t o ensure that ultrasonic activities should be independently budgeted. It was further felt that ultrasonic facilities should be available for all interested clinicians with freedom of access both for training and clinical usage. It was also recommended that, in general, ultrasonic departments should be contiguous with rather than a part of established departments of radiology. It has already become obvious that there is money in this subject not only t o industrialists who are producing the apparatus but t o those who use it. In the very success of sonar may lie the seeds of its destruction and to a wholetime salaried professor like myself these financial considerations are naturally alien. On the industrial side, my blood curdles at talk of patents and exclusive secrecy against industrial espionage. To the medical user, be he radiologist or obstetrician, the danger of conflict as t o where the fees should be paid is greater in the United States than it is in Great Britian where there is no such thing yet as private sonar, and the whole practice in the United Kingdom is wrapped up in our socialized National Health Service. Nevertheless, we suffer from similar financial rivalries with regard to acquiring apparatus, securing personnel, and, of interest t o me particularly, of funds for research. Physicists, too, have much t o gain or lose, and there is great danger in yielding t o the economic arguments in favor of integrating sonar with other fancy diagnostic techniques, such as thermography and established nuclear medicine. Without a doubt progress will only come from continued diversification of interest and not concentration and regimentation of ideas and finances. In that direction lies the stupefying putrefaction of bureaucracy. In the economic climate of today we, particularly in our country, suffer all manner of frustrating economies directed against public expenditure. These economies are mainly effected a t the expense of those of us in the front line whose primary responsibility is direct patient care, against our researches and our acquisition of apparatus, t o say nothing of our ancillary helpers. By contrast our top-heavy, non-productive, committee-ridden administrative system grows apace with its army of secreVOLUME 4. NUMBER 5
taries and its ever-increasing deluge of paper and verbiage in execrable English. Thank goodness there are still shining exceptions! Nor let us overlook the possibility of growing conflict between technical staff, whether they call themselves radiographers or ultrasonographers. Their clamor for recognition must not go unheeded. Some of them demonstrate great ability but the diagnostic medical responsibility must remain, for obvious reasons, with the physician. The large literary and research output from Glasgow on the subject of sonar is t o be attributed t o the fact that the work of scanning is almost wholly done by medically trained and qualified personnel and even when a nonphysician does the scanning, as in a minority of cases in my own department, the results are fed on line t o my office on closed circuit television. I blame many of my obstetrical colleagues for their idleness in not embracing this subject. I blame my radiological colleagues for their peculiar failure t o scan more of their patients themselves and for seeking t o report retrospectively on a series, quite often unnecessarily large, of photographs or transparencies taken for them, just like reporting on xray films. This is no way t o learn the art or t o contribute fresh material after the patient has left the department. Already bottlenecks in training are fully manifest, not only of physicians, but of ultrasonographers, or radiographers, call them what you will. Bad, unsupervised work can only produce bad results and bad results can only react t o the detriment of sonar as a whole. The dustsheet phenomenon awaits the ill-used and the underused apparatus. THE FUTURE
Let me remind my medical colleagues of the two-pronged threat which faces the doctor of tomorrow, nay, even of today in regard to sonar. Not only may some teratongenic or mutagenic disorder be attributed t o ultrasonography in pregnancy, particularly early pregnancy on evidence however flimsy, but also failure to examine by sonar may result in legal controversy, too. I can think of many instances in which we could have found ourselves exposed t o the possibility of a lawsuit through faulty or negligent diagnosis. For example, the prenatal diagnosis of twins and of fetal abnormality are legally very sensitive areas. 327
The advent of real time scanning helps, however, to dispel some of my gloomiest forebodings for the future. Real time scanning requires real time, on the spot, diagnosis. The reporting of movement patterns by an ultrasonic worker will not convince the clinician who must himself interpret their dynamic anatomical significance. He could only do this retrospectively through the medium of videotape as in angiocardiography; in any case the correct interpretation demands the clinical knowledge of a physician be he radiologist or cardiologist. Perhaps after all I can hope for a closer involvement of my clinical colleagues with the introduction of multielement real time scanners suitable for on-line use in the office. Developments such as these must come and come quickly before the physician of today turns his back upon the physics of tomorrow. Sonar is for all of us who profess a genuine interest in its exploitation and development, recognizing that the right t o health, to diagnosis and treatment is universal, or should be, to all mankind.@& V A REFERENCES 1. Stewart A, Webb J, Giles B, and Hewitt D: Preliminary communication. Malignant disease in childhood and diagnostic irradiation in utero. Lancet 2: 447,1956. 2. Stewart A and Kneal GW: Radiation dose effects in relation to obstetric X-rays and childhood cancers. Lancet 1:1185,1970. 3. White DN: The toxicity of ultrasonic and X-ray energy. Ultrasonics in medicine. h o c 2nd World Congr on Ultrasonics in Medicine, Rotterdam, Excerpta Medica, Amsterdam 73,1973. 4. Holmes JH, Howry DH, Posakony GI, and Cushman CR: The ultrasonic visualization of soft tissue structures in the human body. Trans Am Clin Climat Assoc 66: 208,1954. 5. Holmes JH and Howry DH: Ultrasonic diagnosis of abdominal disease. Amer J Dig Dis 8: 12,1963. 6. Howry DH and Bliss WR: Ultrasonic visualization of soft tissue structures of the body. J Lab Clin Med 40: 579,1952. 7. Wild JJ and Reid JM: Application of echo ranging techniques to the determination of structure of biologic tissues. Science 115: 226,1952. 8. Wild JJ and Reid JM: Echographic visualization of lesions of the living intact human breast. Cancer Res 14: 277,1954. 9. Firestone FA: Supersonic reflectoscope, an instrument for inspection of solid parts by means of sound waves. J Acoust SOCAm 17: 287,1946. 10. Willocks J, Donald I, Duggan TC, and Day N: Fetal cephalometry by ultrasound. J Obstet Gynecol Br Commonw 71: 11,1964. 11. Bishop EH: Obstetric uses of the ultrasonic motion scanner. Am J Obstet Gynecol96: 863,1966. 328
12. Johnson WL, Stegall HF, Lein JN, and Rushmer RF: Detection of fetal life in early pregnancy with an ultrasonic Doppler flowmeter. Obstet Gynecol 26: 305,1965. 13. Carlin B: Ultrasonics. McGraw-Hill Book Company, Inc., New York, 1949. 14. Effert S, Erkens H, and Grosse-Brockhoff F: Uber die Anwendung des Ultraschall-Echoverfahren in der Hertzdiagnostik. Deutsch Med Wschr 82: 1253, 1957. 15. Donald I: Apologia: How and why medical sonar developed. Ann Royal College Surg Engl 54: 132, 1974. 16. Donald I: Sonar-The story of an experiment. Ultrasound Med Biol 1: 109,1974. 17. Donald I, MacVicar J, and Brown TG: Investigation of abdominal masses by pulsed ultrasound. Lancet 1: 1188,1958. 18. Donald I and Brown TG: Demonstration of tissue interfaces within the body by ultrasonic echo sounding. Br J Radiol 34: 539,1961. 19. Kossoff G and Garrett WJ: Ultrasonic film echoscopy for placental localization. Austr and NZ J Obstet Gynecol 12: 117,1972. 20. Kossoff G, Carpenter D, Robinson D, and Garrett WJ: A new multi-transducer water coupling echoscope. Proc 2nd Europ Congr on Ultrasonics in Medicine. Kazner E, Muller HR, and de Vlieger M, eds., Munich. Abstract No. 17,1975. 21. Donald I: The use of ultrasonics in the diagnosis of abdominal swellings. Br Med J 2: 1154,1963. 22. Donald I: Sonar as a method of studying prenatal development. J Pediatr 75: 326,1969. 23. Kossoff G, Garrett WJ, and Radavanovich G: Grey scale echography in obstetrics and gynecology. Commonwealth Acoustic Laboratories, Report No. 59, Sydney, Australia, 1973. 24. Railton R and Hall AJ: A simple approach to grey scale echography. Br J Radiol 48: 921,1975. 25. Taylor KJW, Carpenter DA, and McCready VR: Grey-scale echography in the diagnosis of intrahepatic disease. J Clin Ultrasound 1: 284,1973. 26. Taylor KJW and Hill CR: Scanning techniques in grey scale ultrasonography. Br J Radiol 48: 918, 1975. 27. Donald I: Grey-scale imaging in sonar. Scot Med J 20: 177,1975. 28. Donald I: New diagnostic horizons with sonar. The Mackenzie Davidson Memorial Lecture. Br J Radiol 49: 306,1976. 29. Abbowit SH, Jennett RJ, Langhead MK, et al: Assessment of fetal viability with multielement real-time scanning systems. Proc 2nd Europ Congr on Ultrasonics in Medicine. Kazner E, Muller HR, and de Vlieger M, eds., Munich. Abstract No. 219, 1975. 30. Pourcelot L, Pottier JM, Berson M, and Planiol TH: Fast ultrasonic imaging system (USABEL). Proc 2nd Europ Congr on Ultrasonics in Medicine. Kazner E, Muller HR, and de Vlieger M, eds., Munich. Abstract No. 20,1975. JOURNAL OF CLINICAL ULTRASOUND
Ian Donald, Mi),Queen Mother’s Hospital Glasgow , Scotland
This speech was given by Dr. Ian Donald at the opening session o f the World Federation of‘llltrasound in Medicine and’Biology o n August 3rd in San Francisco. Dr. Ian Donald, a guest of AIUM and a guest of the conference, who has been an outstanding figure in the development of diagnostic ultrasound in England, was the speaker. Dr. Donald has given particular attention to the applications o f diagnostic ultrasound in the field o f obstetrics and gynecology. Because o f its general interest t o all in the field o f diagnostic ultrasound, Dr. Brown and I decided to publish the paper both in Reflections and in the Journal of Clinical UltrdSound.
Medical sonar has quite suddenly grown up and come of age; in fact, its growth spurt within the last few years has been almost explosive. This is in marked contrast with its youthful development which was, to say the least of it, somewhat retarded. Its history is very different from that of X radiology, which burst upon the world with eclat following Roentgen’s humble publication in 1895, such that within a few years in England the Roentgen Society had already been formed. Dreadful irradiation casualties followed in its wake, and I am old enough to recollect the sheer horror of some of the injuries inflicted, especially on the pioneers in that exciting field. My own unmentionable disregard for precautions as a young man when handling radium and xrays would horrify the physicist of today. Sonar, a t least, has exacted no such demonstrable toll, but vigilance must remain both now and in the future (1,2) even though we fully recognize that we are dealing only with mechanical energies rather than those derived from the electromagnetic spectrum and that consequently the possibility of delayed sinister effects can reasonably be ignored. To quote Denis White at the Rotterdam conference, “so long as this energy is kept below the level of intensity that would disrupt the forces that bind the tissues together, no tissue damage is likely to occur. If this level should be exceeded, then all the tissue VOLUME 4, NUMBER 5
in the supra-threshold regon would be affected in contrast with the scattered atoms affected by Xradiation. Thus, theoretically at least, small intensities of ultrasonic energy are harmless; small intensities of Xradiation are always harmful, albeit it is not grossly so” (3). In recognizing the “ultrasonic boom” at present with us, we must acknowledge the genius of those to whom the subject owes so much. I refer particularly to the late Douglas Howry, whom I had the privilege of meeting both in London and in Pittsburgh, Pennsylvania, and whose enthusiasm was totally infectious (4-6). Also Wild, whose exuberance was by no means misplaced (7,8). Notable physicists and engineers have been mainly responsible for the exploitation of Firestone’s original work on metals (9) and although it might be invidious to pick out only a few, I personally cannot help acknowledging Reid in the United States and Tom Brown in Scotland as among the really inventive geniuses, nor can I fail to acknowledge the help of Tom Duggan also in Scotland for his contribution of superimposing electronic cursors which have made accurate measurement one of our mainstays in producing worthwhile results (10). The exploitation of the ultrasonic Doppler effect (11, 12) is something about which I was guilty of being skeptical, and in fact I can remember so advising Carlin: upon whose textbook 323
on the physics of ultrasound I had so greatly relied myself (13). Fortunately, my advice was ignored and the subject went ahead with today’s brilliant resdts. To Effert and his colleagues in Germany ( 1 4 ) , I and many others owe a debt for introducing us to the first attempts to make use of time-motion scanning which has proved so profitable in cardiology. It is necessary, however, for some physician intellectually orientated towards the physics of ultrasound to integrate the whole subject, and here I think we must all acknowledge the wonderful achievements of Joseph Holmes whose energy, enthusiasm, and generosity have sustained not only him but us as well over all these years, ever since I first met him in 1963. I think Joe Holmes has done more than anyone to pull us all together from our several pathways. It will be noted that the above were not simply drawn from the ranks of clinicians, nor radiologists, nor physicists, nor any other type of technologist. The present state of the ultrasonic art has grown out of the corporate effort of workers with many different backgrounds and long may it remain so. I shall have more to say on the subject of “market cornering” presently. It can be seen that the technical brilliance that has emerged in the last 10 years cannot be adequately itemized and if momentum in terms of physics is represented by the product of mass x velocity and if force can be described in terms of acceleration, then the mind boggles at the scale of advances that lie immediately ahead. In our own case it was not an abstract academic interest that motivated us. It was the sheer, stark, clinical reality of a difficult differential diagnosis in the subject of the grossly distended abdomen which at that time interested me and which clearly saved a woman’s life by diagnosing with Ascan sonar, even in those far off days, a truly gigantic ovarian cyst which was perfectly benign. Her state had been wrongly attributed, not without reason, to acute distension from malignant portal obstruction, secondary to a misdiagnosed carcinoma of stomach, thanks to a radiological artifact. Her plight was pitiable as she lay vomiting blood and dying and was in such marked contrast to her instant recovery following my removal of this tumor that we became inevitably committed, as did my engineering friends from whom I borrowed the ultrasonic equipment. From that moment morally there could be no going back. After all, what price a woman’s life? Thereafter one thing led to another which led to another, 324
and the great drive to exploit a new diagnostic technique got under way (15 , 16). BREAKTHROUGH EVENTS
To those of us who have worked in the ultrasonic field for more than 20 years, certain events have in their several ways produced a breakthrough. 1. The conversion of Ascan to Bscan, to be followed later by combining the two and adding time-motion scanning. 2. The development of contact scanning(l7, 18).We have always regarded this as desirable in the interests of convenience, maneuverability, and patient acceptability. The subject, however, was not without its difficulties, and we are well aware of the high quality of pictures (19,20) which can be obtained through the medium of water tanks. In the first instance compound B scanning was necessary in order to reveal the anatomical outline studies of structures, whether of tumors or their relationship to neighboring viscera, or fetal parts, particularly the head dimensions and also for placental localization. Our dependence on specular reflection has lessened with further refinement and the information yield has increased without the resolution losses which are inherent in compounding. 3. The exploitation of the ultrasonic Doppler effect. This had an immediate success in recording the fetal heart, even in fairly early pregnancy, but is likely to prove increasingly useful in bloodflow studies. 4. The development of the full bladder technique which not only incorporates all the advantages of a built-in water tank but allows ultrasonic access to structures deep within the pelvis, so that extensive studies, for example, of very early pregnancy and fetal development can now be made i(21, 22). 5. Gray-scale imaging. Whether achieved by highly developed and sophisticated logarithmic compression amplifiers (23-26) or by the principle of scan conversiQn (27, 28), there is no doubt that a whole new diagnostic range in the study of tissue structure has been opened up with this new technique. It is particularly important in such diverse subjects as hepatic diseases, including malignant metastases and placental studies. The useful point about scan conversion techniques is that even inexperienced operators can still produce good pictures even though guilty of overwriting, thanks t o the builtin peak value memory. Where degradation in a gray scale picture occurs, especially in obstetrics, JOURNAL OF CLINICAL ULTRASOUND
FIGURE 1. Blighted o v u m in very early pregnancy, Embryonic sac evacuated, Contained only a small disorganized fetal pole.
FIGURE 2. Normal early pregnancy. N o t e fetus (arrow) and placenta differentiating at fundus. Black on w h i t e picture.
touch ultrasonics with a bargepole. He had now changed course to a 180" reciprocal, rather like what happened on the road t o Damascus. 2. Opportunities Wantonly Missed. It was constantly galling t o be greeted by a colleague who remembered a patient who might have yielded interesting ultr+onic results, and on our immediate inquiry as to her whereabouts to be told regretfully that she had either died or been dismissed home and could not be recalled. Louis Pasteur was indeed right when he talked about the chance observation and the prepared mind. 2. The Stage of Overacceptance. Now the impossible was expected of us. The most bizarre STAGES IN DEVELOPMENT and unexpected tumors were expected t o be immediately diagnosed, and in self protection I, like others of my generation, have lived through five stages which we can easily identify, one was reduced to explaining to an everincreasing extent the limitations of existing not without a trace of cynicism. 1. Disbelief. If it had not been for the gener- sonar techniques. This stage of overacceptance was also the ous help of friends in the engineering world, we might well have foundered here. The attitude of stage of our greatest mistakes from which we one's colleagues was on the whole good-natured learned so much. Throughout, mistakes have such as might be shown towards the eccentrici- proved more instructive than successes. It is ties of a fairly harmless lunatic. When it came to a hard philosophy but one which must be acraising money, however, the situation was cepted. Some of them have been simple enough, somewhat less favorable. I can still recall with for example, the twins which did not materialannoyance the frivolous comment of one of ize, or the cheerfully monitored pregnancy my alleged friends from the rival city of Edin- which finally ended in the wrong number of burgh who returned home full of my wife's fetuses. Our mistakes in diagnosing an abnormal wine and excellent cuisine only to announce to blighted pregnancy have been gradually elimia hilarious group of students that in Glasgow we nated (Fig. l), especially with studies of the needed a machine, then costing about $10,000, fetal heart from the sixth week of amenorrhea to diagnose an ovarian cyst which he with his onwards (Figs. 2, 3), but on the subject of fetal God-given clinical acumen could diagnose with a abnormality we have much yet to learn (Fig. 4). The prenatal diagnosis of fetal handicap is twopenny glove. The mistakes of which we were guilty at that time taxed both my authority and now occupying an ever-increasing role in modern the forbearance of those who had sought my obstetrics. If I with 38 years of clinical experidiagnostic help. An eminent physicist was once ence can make mistakes, how much more likely heard to apprise a personage in authority not to are they to be made by the less knowledgeable; it is probably due to fetal movement, the extent of which can only be satisfactorily revealed by the more newly developed methods of real time scanning. 6. Real time scanning. Until recently real time scanning systems have been largely thwarted by poor resolution and intolerable flicker, faults inherent in design using single transducers. The more modern employment of multielement transducer arrays, sequentially fired, however, now produces a real, live picture of what is going on while it is going on. A new dynamic element is thus introduced into diagnosis. (29, 30).
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FIGURE 3. Fetal heart of same case as Figure 2 recorded a f e w days later. Maturity 8-9 weeks.
FIGURE 5. Postnatal ultrasonic renogram i n severe case of systemic lupus erythromatosis involving kidneys. Transverse dorsal view. N o t e small kidneys w i t h narrowed parenchyma.
tions of men are vying with each other to secure a place in the ultrasonic sun. It goes without saying that the last t o climb on the bandwagon will be the first to jump off at the first sign of trouble or danger. This would .be all acceptable enough if it did not carry with it attempts to corner the market. WHOSE RESPONSIBILITY?
FIGURE 4. Enormous cystic hygroma of neck; wrongly diagnosed as omphalocele. No placenta posteriorly.
and I can say in all clinical humility that if there is any diagnostic mistake which I have not yet made, there is still time for me to make it. Nevertheless, when bad sonar is combined with bad clinical diagnosis the results can be truly disastrous and reflect discredit on the whole subject. With the latest gray scale imaging techniques I think, however, that we have now reached somewhere very near the ultimate in what can be achieved with two dimensional scanning with single probe machines (Fig. 5). 4. The Stage of Justification. The mounting expenses could assuredly by justified by results, certainly in obstetrics. Sonar has indeed transformed the practice of obstetrics in innumerable directions, and we have reached the stage where most of us who have reaped the benefit would be very loath to continue to practice without it. Sonar has in no way replaced clinical judgment but it has certainly improved it. 5. The Bandwagon Stage. This is a new form of overacceptance in which all sorts and condi326
The day is fast approaching when sonar should be regarded as a discipline in its own right. Of course radiologists must understand it, and the Royal College of Radiologists has made a knowledge of the subject a part of its requirements for the Fellowship Examination in England. Of course, obstetricians should know and understand it, and in fact a couple of years ago t h e first question in the paper for the M.R.C.O.G. Diploma was on the subject of sonar. Of course, cardiologists should know the subject as much as they are at present expected t o understand electrocardiography. I would disagree most strongly with the view, which I have already encountered, that sonar should be treated as an integral part of radiology only. There is already great danger of a conflict of interests of established departments. There must be no market cornering and no confrontation between departmental and parochial interests. Nothing could be more detrimental to further advance. The danger has already been foreseen in England by the Royal College of Obstetricians & Gynecologists and the Royal College of Radiologists, numerically still the most important groups, although cardiologists, urologists, and i’nternists are likely soon to enter the lists before it is too late. JOURNAL OF CLINICAL ULTRASOUND
On behalf of thes two Royal Colleges some very wideranging discussions have taken place in which I was involved. The recommendations include the setting up of a standing Liaison Committee to keep the possibility of hazard under review and t o ensure that ultrasonic activities should be independently budgeted. It was further felt that ultrasonic facilities should be available for all interested clinicians with freedom of access both for training and clinical usage. It was also recommended that, in general, ultrasonic departments should be contiguous with rather than a part of established departments of radiology. It has already become obvious that there is money in this subject not only t o industrialists who are producing the apparatus but t o those who use it. In the very success of sonar may lie the seeds of its destruction and to a wholetime salaried professor like myself these financial considerations are naturally alien. On the industrial side, my blood curdles at talk of patents and exclusive secrecy against industrial espionage. To the medical user, be he radiologist or obstetrician, the danger of conflict as t o where the fees should be paid is greater in the United States than it is in Great Britian where there is no such thing yet as private sonar, and the whole practice in the United Kingdom is wrapped up in our socialized National Health Service. Nevertheless, we suffer from similar financial rivalries with regard to acquiring apparatus, securing personnel, and, of interest t o me particularly, of funds for research. Physicists, too, have much t o gain or lose, and there is great danger in yielding t o the economic arguments in favor of integrating sonar with other fancy diagnostic techniques, such as thermography and established nuclear medicine. Without a doubt progress will only come from continued diversification of interest and not concentration and regimentation of ideas and finances. In that direction lies the stupefying putrefaction of bureaucracy. In the economic climate of today we, particularly in our country, suffer all manner of frustrating economies directed against public expenditure. These economies are mainly effected a t the expense of those of us in the front line whose primary responsibility is direct patient care, against our researches and our acquisition of apparatus, t o say nothing of our ancillary helpers. By contrast our top-heavy, non-productive, committee-ridden administrative system grows apace with its army of secreVOLUME 4. NUMBER 5
taries and its ever-increasing deluge of paper and verbiage in execrable English. Thank goodness there are still shining exceptions! Nor let us overlook the possibility of growing conflict between technical staff, whether they call themselves radiographers or ultrasonographers. Their clamor for recognition must not go unheeded. Some of them demonstrate great ability but the diagnostic medical responsibility must remain, for obvious reasons, with the physician. The large literary and research output from Glasgow on the subject of sonar is t o be attributed t o the fact that the work of scanning is almost wholly done by medically trained and qualified personnel and even when a nonphysician does the scanning, as in a minority of cases in my own department, the results are fed on line t o my office on closed circuit television. I blame many of my obstetrical colleagues for their idleness in not embracing this subject. I blame my radiological colleagues for their peculiar failure t o scan more of their patients themselves and for seeking t o report retrospectively on a series, quite often unnecessarily large, of photographs or transparencies taken for them, just like reporting on xray films. This is no way t o learn the art or t o contribute fresh material after the patient has left the department. Already bottlenecks in training are fully manifest, not only of physicians, but of ultrasonographers, or radiographers, call them what you will. Bad, unsupervised work can only produce bad results and bad results can only react t o the detriment of sonar as a whole. The dustsheet phenomenon awaits the ill-used and the underused apparatus. THE FUTURE
Let me remind my medical colleagues of the two-pronged threat which faces the doctor of tomorrow, nay, even of today in regard to sonar. Not only may some teratongenic or mutagenic disorder be attributed t o ultrasonography in pregnancy, particularly early pregnancy on evidence however flimsy, but also failure to examine by sonar may result in legal controversy, too. I can think of many instances in which we could have found ourselves exposed t o the possibility of a lawsuit through faulty or negligent diagnosis. For example, the prenatal diagnosis of twins and of fetal abnormality are legally very sensitive areas. 327
The advent of real time scanning helps, however, to dispel some of my gloomiest forebodings for the future. Real time scanning requires real time, on the spot, diagnosis. The reporting of movement patterns by an ultrasonic worker will not convince the clinician who must himself interpret their dynamic anatomical significance. He could only do this retrospectively through the medium of videotape as in angiocardiography; in any case the correct interpretation demands the clinical knowledge of a physician be he radiologist or cardiologist. Perhaps after all I can hope for a closer involvement of my clinical colleagues with the introduction of multielement real time scanners suitable for on-line use in the office. Developments such as these must come and come quickly before the physician of today turns his back upon the physics of tomorrow. Sonar is for all of us who profess a genuine interest in its exploitation and development, recognizing that the right t o health, to diagnosis and treatment is universal, or should be, to all mankind.@& V A REFERENCES 1. Stewart A, Webb J, Giles B, and Hewitt D: Preliminary communication. Malignant disease in childhood and diagnostic irradiation in utero. Lancet 2: 447,1956. 2. Stewart A and Kneal GW: Radiation dose effects in relation to obstetric X-rays and childhood cancers. Lancet 1:1185,1970. 3. White DN: The toxicity of ultrasonic and X-ray energy. Ultrasonics in medicine. h o c 2nd World Congr on Ultrasonics in Medicine, Rotterdam, Excerpta Medica, Amsterdam 73,1973. 4. Holmes JH, Howry DH, Posakony GI, and Cushman CR: The ultrasonic visualization of soft tissue structures in the human body. Trans Am Clin Climat Assoc 66: 208,1954. 5. Holmes JH and Howry DH: Ultrasonic diagnosis of abdominal disease. Amer J Dig Dis 8: 12,1963. 6. Howry DH and Bliss WR: Ultrasonic visualization of soft tissue structures of the body. J Lab Clin Med 40: 579,1952. 7. Wild JJ and Reid JM: Application of echo ranging techniques to the determination of structure of biologic tissues. Science 115: 226,1952. 8. Wild JJ and Reid JM: Echographic visualization of lesions of the living intact human breast. Cancer Res 14: 277,1954. 9. Firestone FA: Supersonic reflectoscope, an instrument for inspection of solid parts by means of sound waves. J Acoust SOCAm 17: 287,1946. 10. Willocks J, Donald I, Duggan TC, and Day N: Fetal cephalometry by ultrasound. J Obstet Gynecol Br Commonw 71: 11,1964. 11. Bishop EH: Obstetric uses of the ultrasonic motion scanner. Am J Obstet Gynecol96: 863,1966. 328
12. Johnson WL, Stegall HF, Lein JN, and Rushmer RF: Detection of fetal life in early pregnancy with an ultrasonic Doppler flowmeter. Obstet Gynecol 26: 305,1965. 13. Carlin B: Ultrasonics. McGraw-Hill Book Company, Inc., New York, 1949. 14. Effert S, Erkens H, and Grosse-Brockhoff F: Uber die Anwendung des Ultraschall-Echoverfahren in der Hertzdiagnostik. Deutsch Med Wschr 82: 1253, 1957. 15. Donald I: Apologia: How and why medical sonar developed. Ann Royal College Surg Engl 54: 132, 1974. 16. Donald I: Sonar-The story of an experiment. Ultrasound Med Biol 1: 109,1974. 17. Donald I, MacVicar J, and Brown TG: Investigation of abdominal masses by pulsed ultrasound. Lancet 1: 1188,1958. 18. Donald I and Brown TG: Demonstration of tissue interfaces within the body by ultrasonic echo sounding. Br J Radiol 34: 539,1961. 19. Kossoff G and Garrett WJ: Ultrasonic film echoscopy for placental localization. Austr and NZ J Obstet Gynecol 12: 117,1972. 20. Kossoff G, Carpenter D, Robinson D, and Garrett WJ: A new multi-transducer water coupling echoscope. Proc 2nd Europ Congr on Ultrasonics in Medicine. Kazner E, Muller HR, and de Vlieger M, eds., Munich. Abstract No. 17,1975. 21. Donald I: The use of ultrasonics in the diagnosis of abdominal swellings. Br Med J 2: 1154,1963. 22. Donald I: Sonar as a method of studying prenatal development. J Pediatr 75: 326,1969. 23. Kossoff G, Garrett WJ, and Radavanovich G: Grey scale echography in obstetrics and gynecology. Commonwealth Acoustic Laboratories, Report No. 59, Sydney, Australia, 1973. 24. Railton R and Hall AJ: A simple approach to grey scale echography. Br J Radiol 48: 921,1975. 25. Taylor KJW, Carpenter DA, and McCready VR: Grey-scale echography in the diagnosis of intrahepatic disease. J Clin Ultrasound 1: 284,1973. 26. Taylor KJW and Hill CR: Scanning techniques in grey scale ultrasonography. Br J Radiol 48: 918, 1975. 27. Donald I: Grey-scale imaging in sonar. Scot Med J 20: 177,1975. 28. Donald I: New diagnostic horizons with sonar. The Mackenzie Davidson Memorial Lecture. Br J Radiol 49: 306,1976. 29. Abbowit SH, Jennett RJ, Langhead MK, et al: Assessment of fetal viability with multielement real-time scanning systems. Proc 2nd Europ Congr on Ultrasonics in Medicine. Kazner E, Muller HR, and de Vlieger M, eds., Munich. Abstract No. 219, 1975. 30. Pourcelot L, Pottier JM, Berson M, and Planiol TH: Fast ultrasonic imaging system (USABEL). Proc 2nd Europ Congr on Ultrasonics in Medicine. Kazner E, Muller HR, and de Vlieger M, eds., Munich. Abstract No. 20,1975. JOURNAL OF CLINICAL ULTRASOUND
