A short History of the development of Diagnostic Ultrasound in Japan (with reference to Obstetrical and Gynecological applications)

Dr. Joseph Woo

The development of ultrasonic investigations in Japan can be traced back to the Tohoku University in Sendai. Between 1917 to 1919, Professor Heiichi Nukiyama at the Department of Electrical Engineering, studied electroacoustic transducers at the Harvard University in Boston, United States with Physics Professor A. E. Kenelly.

After Nukiyama's return to the Tohoku Imperial (then Imperial) University in Sendai, he co-founded the department of Engineering at the university and taught ultrasonics in his department. His teachings subsequently spread through his many student researchers and engineers throughout Japan. In 1936, Nukiyama was awarded the highest prize on science and technology in Japan, the Asahi Prize, on the development of underwater telephony (hydrophony) and magnetostriction ultrasonic transducers. Professors Yoshimitsu Kikuchi and K. Shibayama of Tohoku University, and Professor Junichi Saneyoshi of the Tokyo Institute of Technology - all students of Nukiyama - developed ultrasonic apparatus in such fields as underwater ultrasonics (for world war II) and non-destructive testing. Many engineers working in the ultrasonics industry later on have continued their good relationships with Tohoku University.

The research into ultrasonic metal-flaw detection in Japan was curtailed when World war II broke out in 1941, at which time the Americans and the Germans were both diligently researching into ultrasonic applications and the development of the Radar. The study into Radar techniques in Japan was also in the disadvantage. The first commercial flaw detector was marketed in the United States in 1945 under the Sperry UR label (after the Firestone patents) and as the war ended in 1945, research into high-power electronics was prohibited in Japan for some time (up till 1948, when developments of non-military electronics resumed). Donald Sproule in Britain produced their version in 1946 under the Kelvin and Hughes label.

Japanese enterprises took on the research from the U.S. and England and soon developed its own flaw detectors in non-destructive testing. By about 1949, four Japanese companies started to manufacture their own flaw dectors. These were: the Mitsutbishi Electric Corporation, the Japan Radio Company ( later became the Aloka Company), the Shimadsu Manufacturing Company and the Toyko Ultrasonic Industrial Company. Only Mitsubishi continued to expand in the field of non-destructive testing and the other companies either dropped out of the competition, moved on to other areas or diverged into diagnostic medical ultrasound applications. The Japanese Society for Non-Destructive Inspection officially recognised the year 1952 as the first year non-destructive testing was implemented in Japan.

Two earliest metal flaw detectors from Japan, both around 1950. The left from Mitsubushi Electric and the right from the Japan Radio Company (Aloka). The Mitshubishi Electric Coporation continued to expand in the field of non-destructive testing while the Aloka Company ventured into ultrasonic medical diagnostic applications.

Professor Kenji Tanaka at the Juntendo University, Tokyo was one of the very early pioneers in employing ultrasound as a diagnostic tool. Motivated by the ability of ultrasound waves in detecting fish fleets in the sea and flaw detection in metals, Tanaka had plans for using ultrasonics in the detection of intra-cerebral tumors in the late1940s. He sought help and advice from Shigeru Nakajima**, then director of the Japan Radio Company. Nakajima had around this time invented an ultrasonic device for the detection of fish fleets in the sea. Together with Dr. Toshio Wagai, resident neuro-surgeon in the department, ultrasonic engineer Yoshimitsu Kikuchi from Sendai and Rokuro Uchida, chief engineer from the Japan Radio Company, they began to look into the use of ultrasound in the diagnosis of intracranial lesions. (see below). The Japan Radio Company later became the Aloka Company in 1950, headed by Uchida. Uchida built Japan's first ultrasonic scanner operating in the A-mode in 1949, likewise from other parts of the world, from a modified metal flaw-detector. In 1952 the group reported on the detection of intracerebral hematomas and tumors. Later on Wagai also applied ultrasound to the detection of gall-stones and breast tumors. Further research proceeded with the fish-locator devices which were soon developed into B-mode apparatus.

Toshio Wagai was born in 1924 in Sendai, Miyagi Prefecture. He entered the Niigata Medical University in 1945 and graduated in 1949. After graduation he went to Tokyo and became an intern in the area of Kanda Suruga. There he was aquainted with a friend who worked at the factory of the Ishikawajima Heavy Industries, a graduate from the engineering department of the Tohoku University in Sendai. Wagai had thoughts that it might be possible to apply ultrasonic methods to the human body for medical diagnosis. He soon joined the Department of Surgery at the Juntendo University as a research assistant in 1950, under the supervision of Kenji Tanaka, who was, at that time having had plans of looking at the use of ultrasonics in neurological diagnosis. Tanaka had learned of the appications of ultrasonics in underwater detections (fish and submarines), metal flaw detections and Karl Dussik's medical applications on the human brain. A look into the Japanese literature showed that medical applications of ultrasonics had not been embarked upon in Japan.

Wagai was told of the operation of metal flaw detectors at the reseach department of the railroad technology section of the factory and went over to looked at how metal flaws were detected from the different wave patterns shown on the osciloscope. Wagai was trying to start work on neurological diagnosis using the device. As the metal flaw detector could not be moved out of the factory, Wagai had to bring into the factory many different pathological brain tissue to experiment, at which he spent much time in studying the different wave patterns. Wagai had often commented that ultrasound diagnosis in Japan had originated at the Ishikawajima Factory!

In the fall of 1951 he was introduced to the Director Shigeru Nakajima** and Rukuro Uchida of the Japan Radio Company Ltd. Formal research soon started at the Juntendo University hospital with Kenji Tanaka and G Miyajima , with help from Shigeru Nakajima, Rukuro Uchida and Yoshimitsu Kikuchi from the Tohoku University, Sendai. In 1952, Wagai presented at the Japan Accoustics Society the paper "Ultrasonic examination of the human body - first report". In the same year their department published 5 papers in ultrasound diagnosis and all 5 were on the diagnosis of intracranial abnormalities. By 1956, Wagai had published the 7th report which had covered the diagnosis of breast and abdominal pathologies. Thereafter ultrasonic research had started to boom in Japan.

  Read here the Preface and introduction (history) to Tanaka's book "Diagnosis of Brain Disease by Ultrasound" published in 1969 for a short history of his pioneering work in the 1950s.

In 1956, the MIT hosted a historical conference in Bioacoustics and Wagai was invited to speak. Those who also attended included Kikuchi, Dussik, Bolt, Ballantine, Heuter, Wild, Fry and Howry. Many of them met each other for the first time and important views concerning methods and instrumentations were exchanged at the meeting. Wagai working in collaboration with physicist Masao Ide at the Musashi Institutes of Technology and Junichi Saneyoshi at the Toyko Institute of Technology, had already started important research of ultrasonic bioeffects in the late 1950s. In 1965, his paper with Kenji Tanaka and others on "Ultrasonic Diagnosis in Japan" was presented at the "First International Conference on Diagnostic Ultrasound" held in Pittsburg, Pensylvannia.

Toshio Wagai became Associate Professor of the Department of Surgery at the Juntendo University in 1965 and was promoted to full Professorship in 1970 when he was also appointed Head of the Ultrasound Research Facilities. In 1988 he was appointed by the government to sit on the Science Council of Japan. Wagai retired in 1990 at the age of 66 and in the same year was made Professor Emeritus of the University.

He has also been elected the President of the World Federation of Ultrasound in Medicine and Biology (WFUMB, 1976), the Asian Federation (AFSUMB, 1985) and the Japan Society of Ultrasonics in Medicine (JSUM, 1982). A true pioneering figure in ultrasonography, Wagai has received numerous prizes and awards and many of them were conferred on him by the Japanese government and international organizations.

A biography of Dr Wagai in Japanese can be found here.

** Shigeru Nakajima was born in Japan in 1910. He attended Wasada university and studied power engineering. Though he graduated during the Great Depression, he was able to secure a job with the Japan Radio Company (JRC). In the late 1930s, he took a position with Telefunken of Berlin to work on phototubes, magnetrons and vacuum tube getters. During World War II, Nakajima and his brother worked in Germany and Japan on such projects as military radar, the atom bomb and a ray weapon. In the post war period, JRC experienced materials shortages at the same time research and productions were all restricted to non-military markets. Nakajima was head of the JRC. The company developed new applications including microwave communications and ultrasonic fish locators for commercial fishing. The fish locator was so successful that some were sold to the U.S. and other countries. Nakajima was approached by Kenji Tanaka on adaptation of such fish locating devices to human diagnosis. He did not considered it easy but had successfully helped Tanaka at the Juntendo University to develop such a device for the next 20 years. The JRC subsequently became the Aloka Company.

In 1954, Tanaka published an important review entitled "Application of ultrasound to diagnostic field", and investigations had started with other body organs. By 1955, experiments and fabrication with B-mode scanning had started using a similar scope modified from the original A-mode machine coupled with a linear moving transducer gantry. This was shortly developed into the water-bag scanners.

S. Oka at the Tohoku University also used ultrasonic techniques to diagnosis brain tumors and was well-known for his work on the therapeutic use of ultrasonic waves. Work at the Juntendo University in Toyko continued to produce newer designs employing water-bag and water-bath mechanisms. These operated both in the A- and B- modes and were used for brain and breast scanning and later investigation of the liver and other body organs.

Yoshimitsu Kikuchi was very active in equipment designs, and by 1957 he was able to demonstrate a prototype "one-point contact-sector scanning tomography" using the plan-position indication (PPI) B-mode format, which had a resemblance to a 'radar display'. This development, which was at around a similar time as the pioneering work of Howry in Denver, Colorado and Ian Donald in Glasgow, Scotland, had a similar concept of "position-referenced contact scanning". The PPI scanners were initially used for brain scans and later expanded its use in Obstetrics and Gynecology.

Michio Ishihara at the National Sanatorium Kiyose Hospital in Tokyo and Hajime Murooka at the department of obstetrics and gynecology, Oomiya Red Cross Hospital, Saitama, delivered the first paper on ultrasound diagnosis of gynecological masses in the Japanese language at the 19th Kanto District Meeting of the Japanese Obstetrical and Gynecological Society in 1958, basing on the A-scan. Murooka had earlier in 1957 received instructions from Wagai on the A-scan methods at the Juntendo University.

They described A-scan echoes in cancer of the cervix and also in the presence of different causes of uterine enlargement. Wagai published a review article in the use of ultrasound in Obstetrics and Gynecology in 1959. The abstract of the paper is seen in the Tokyo District Journal of the Japanese Obstetrical and Gynecological Society under the title of "On diagnosis of obstetrical and gynecological diseases by ultrasound - 1st report". They presented the 2nd report at the 11th Annual Meeting of Japanese Obstetrical and Gynecological Society in 1959. Wagai et al presented a paper "Application of ultrasound diagnostic technique in obstetrics and gynecology" at the same Meeting. Ishihara published in 1960 the paper: "On the research of gynecological and obstetrical diagnostics with ultra-sonic-reflex-method. (Acta Obstet Gynecol Jap 1960;12:1829-1838, in Japanese), This was one only original paper by Ishihara on the subject. The Murooka group did not continue their work after the first two papers presented at the meetings.

Aloka® produced their first Commercial medical A-scanner, the SSD-2 and the water-bag B-scanner, the SSD-1 in 1960 (pictured on the left). The application of B-mode ultrasound to Obstetrical and Gynaecological diagnosis in Japan started around 1962 basing on the use of the "one-point contact-sector scanner" in the plan-position indication (PPI) B-mode format. Early commercial water-bag scanners were being produced by Aloka® and Toshiba® in the early 1960s.

Transducer design was under much research and deveopment. Notable figure in this area was Professor Y Torikai at the Tokyo University. His work led to the development of smaller concave transducers with narrower beamwidth and better resolution. At the Tohoku University in Sendai, in collaboration with Kikuchi, Oka and others, Motonao Tanaka was very active and productive in 2-D ultrasonic reseach in cardiology.

Shigemitsu Mizuno, Hisaya Takeuchi, Koh Nakano and Masao Arima followed up the work at the Juntendo University in Tokyo, Japan from around 1962 and experimented with new versions of the A-mode transvaginal scanner. The first ultrasound scan of a 6-week gestational sac by vaginal A-scan was reported in the Japanese language in 1963. From 1962, the group worked extensively with the water-bag B-scanner, the SSD-1 and was very active in many areas and producing a huge number of research publications, ranging from early pregnancy diagnosis to cephalometry to placentography. They also reported on a large series of pelvic tumors in 1965, and in the following 2 years switched from the water-bag contact scanner to the articulated-arm compound contact scanner, the SSD-10. Another group consisting of T Tanaka, I Suda and S Miyahara started researches into the different stages of pregnancy in 1964.

Shigemitsu Mizuno also demonstrated in 1964 an endovaginal scanner for pelvic examination using a plan-position indication (PPI) B-mode format. The device was mannually rotated and the resulting display was very similar to a circular military 'Radar" display. Used either transrectally or transvaginally, It was capable of producing some meaningful pictures of the pelvic organs. A list of the early paper can be found at Hisaya Takeuchi.

Kazuo Maeda at the Tottori University in Toyko worked with doppler fetal heart rate recording since the late 1960s and developed various devices for fetal cardiotocography. In collaboration with Masao Ide of the Mushashi Institute of Technology they investigated ultrasonic bioeffects and established safety Guidelines for ultrasound use in clinical practice.

The Japan Society of Ultrasonics in Medicine was founded in 1962 by Wagai, Ide and others. At that time there were 200 members.

Rokuro Uchida at Aloka® had been embarking on research in real-time linear array technology in the early 1970s predating their European counterpart. In 1971 their group described in Japanese a system based on 200 closely interspaced transducers. Electronic switching and use of overlapping groups of 20 small elements yielded 2-D images at a rate of 17/frames per second. The company produced their first prototype linear array scanner in the same year. The first commercial linear array scanner from Aloka® debuted in 1976. Toshiba® produced their first commercial real-time linear array counterpart in the same year, the SSL-53H, aimed at abdominal applications. Being one of the largest companies in the world in the manufacture of medical equipments, Toshiba® announced the production of their 100,000th ultrasound scanner in 1996.

Linear array and annular array technology were heavily investigated by the Japanese after the mid 1970's. The country had been moving ahead very successfully with innovative electronic engineering in many domestic, commercial and professional sectors. Commercial linear array models from companies like Toshiba®, Hitachi® and Aloka® soon began to dominate the world market. Hitachi® also produced their first linear array scanner the EUB-10 in 1976. The Toshiba® SAL-10A and the more portable 20A (pictured on the left), which were marketed in 1977 and 1978 respectively, and the Aloka® SSD-202 (1979), SSD-203 (1980), SSD-240 (1981) and SSD-256 (1982) were popular and had found their way into notable Institutions outside of Japan such as the King's College Hospital in London (Campbell), the Herlev Hospital in Denmark (Holm), the Hospital Universitaire Brugman in Belgium (Levi) and were employed in many important early studies. The SAL-10A which was designed by acclaimed Japanese engineer Kazuhiro Iinuma, received many commendations. Kazuhiro Iinuma, a PhD in Engineering, was responsible for much of the development of the electronic scanners at Toshiba® and for many important inventions and innovations.

A summary of the landmark development of ultrasound scanners in Japan is as follows:

  • 1950    Rokuro Uchida made the first A-mode scanner from a metal flaw detector.
  • 1950    Experiments with A-mode scanning on brain specimens at the Juntendo University, Toyko (Kenji Tanaka, Toshio Wagai, Yoshimitsu Kikuchi and others)
  • 1954    A-mode scanning applied to clinical brain diagnosis using direct contact brain scanning, Juntendo.
  • 1954    A-mode scanning experiments using water-bath scanners, Juntendo.
  • 1954    A-mode diagnosis of breast diseases, Juntendo.
  • 1955    A-mode scanning applied to clinical brain diagnosis using water-bath brain scanners, Juntendo.
  • 1955    Experiments with first water-bath B-mode scanner, Juntendo.
  • 1955    A-mode and B-mode diagnosis applied to breasts, limbs, abdomen, gall-bladder, heart and lungs, Juntendo.
  • 1955    Shigeo Satomura in Osaka built and 'invented' the first doppler flowmeter.
  • 1956    First attendence of overseas meeting on ultrasound diagnosis by Wagai at M I T.
  • 1956    Fabrication of the second generation B-mode water-bath scanner, Juntendo.
  • 1957    Yoshimitsu Kikuchi produced the one-point contact-sector scanning tomography using the plan-position indication (PPI) B-mode format, Juntendo.
  • 1957    First work with A-mode in Gynecology (Michio Ishihara and Hajime Murooka), tokyo.
  • 1960    Aloka® produced their first commercial medical A-scanner, the SSD-2.
  • 1960    Aloka® produced their first commercial medical B-scanner, the SSD-1 (water-bath).
  • 1960    Ziro Kaneko and Shigeo Satomura built the first "Ultrasonic Blood Rheograph" (spectral analysis) with NEC.
  • 1962    Point-contact B-mode scanning and water-bag scanning applied to Obstetrics and Gynecology.
  • 1966    Kanemasa Kato and T Izumi developed for the first directional doppler flow-meter in Osaka.
  • 1967    Toshiba® produced their first A-mode scanner, the SSA-01A.
  • 1967    Toshiba® produced their first compound contact B-scanner, the TSL system.
  • 1971    Aloka® produced the world's first prototype real-time linear array scanner.
  • 1971    Hitachi® produced their first A-mode scanner the EUA-1.
  • 1972    Hitachi® produced their first B-mode scanner the EUB-1.
  • 1974    Toshiba® produced the first mechanical real-time sector cardiac scanner the SSL-51H.
  • 1976    Aloka® produced their world's first commercially available real-time linear array scanner.
  • 1976    Toshiba® produced their first (non-portable) real-time linear array scanner, the SSL-35H.
  • 1976    Hitachi® produced their first real-time linear array scanner the EUB-10.
  • 1977    Toshiba® produced the SAL-10A portable real-time scanner.
  • 1978    Toshiba® produced the popular SAL-20 portable real-time scanner.
  • 1978    Shimadsu® produced their first real-time linear array scanner the SDU-100.
  • 1979    Aloka® produced their first digital scan converter.
  • 1979    Shimadsu® produced their high resolution real-time linear array scanner the 'Shimazonic'.
  • 1981    Aloka® produced the popular SSD-256 linear array scanner.
  • 1983    Yokogawa® produced the U-sonic system (a system similar to the GE RT3000).
  • 1983    Hitachi® produced the world's first convex electronic array transducer on their EUB-40.
  • 1984    Aloka® produced the world's first real-time color flow doppler scanner the SSD-880CW.
  • 1985    Toshiba® produced their first color-flow scanner the SSH-65A.

Ultrasonic doppler techniques were first implemented by Shigeo Satomura and Yasuhara Nimura at the Institute of Scientific and Industrial Research in Osaka, Japan in 1955 for the study of cardiac valvular motion and pulsations of peripheral blood vessels. In 1955, Satomura began using microwave and ultrasound in medical diagnosis, and tried to apply these to the measurement of the heart and pulsations of peripheriral and eye blood vessels. In December 1955, Satomura published his first paper on the subject entitled "A new method of the mechanical vibration measurement and its application". In this paper he demonstrated that doppler signals can be retrieved from heart movements when insonated with 3 MHz ultrasonic waves. [More]

In 1966, K Kato and T Izumi developed a directional flow-meter using the local oscillation method where flow directions were detected. Reverse flow in the arteries could then be documented. The directional doppler was also indepently developed by F McLeod in the United States in the same year, based on a different principle, the phase-shift methodology. In the late 1960s the Takeuchi group was very active in the development of pulsed doppler devices. The development of pulsed Doppler instruments by this groups enabled non-invasive localised measurements of blood velocity. In addition, their instrument could acquire velocity information at several positions along a vessel's diameter, thus enabling the velocity profile of the blood to be visualised.

Quite unknown to the western world the application of doppler flowmetry in Obstetrics and fetal assessment had started as early as 1968 in Japan, when the H Takemura and Y Ashitaka group described umbilical arterial and placental doppler waveforms at the 14th meeting of the Japan Society of Ultrasonics and Medicine. In the west, the application of doppler ultrasound in Obstetrics other then it's use as a fetal pulse detector did not catch on until 1977 when 3 separate groups of investigators reported on its application in this area.

The work of C Kasai, K Namekawa and A Koyano in Japan, which was published in the English language in 1985, had led to the widespread realization that realtime color flow imaging was a practical possibility. They used a phase detector based on an autocorrelation technique in which the changing phase of the received signal gave information about changing velocity along the ultrasonic beam. This approach to color flow mapping is still in use today.

Advertisements of the first machine(world-wide) with real-time Color flow mapping capabilities from Aloka® (the SSD-880CW) made it's debut in medical journals in the middle of 1985 (It was produced in Japan in 1984). Toshiba® followed up with their SSH-65A later on in the same year.

Compared to the western world, throughout the history of of diagnostic ultrasound, Japanese research has played a leading and major role in its development. Much of the ground-breaking research were presented in national engineering journals and at the annual scientific meeting of the Japan Society of Ultrasonics in Medicine (in japanese) and were thus unknown to the west until a later date.

Kazunori Baba, Associate Professor at the Department of Biomedical Engineering, Graduate School of Medicine, University of Tokyo, first reported on a 3D ultrasound system in 1984 and succeeded in obtaining 3D ultrasound fetal images by using a mini-computer in 1986. This was reported in the Acta Obstetrica et Gynaecologica Japonica. He also applied this system to placental blood flow and breast disorders in 1990 to 1991. Baba wrote a comprehensive book on diagnostic ultrasound in obstetrics and gynecology including 3D ultrasound in 1992 and edited "Three-dimensional ultrasound in obstetrics and gynecology" (Parthenon Publishing), the first book devoted entirely to 3D ultrasound, in collaboration with Davor Jurkovic in London in 1996. In the mid 1990s, Baba collaboration with ALOKA?on technology developed at the Biomedical Engineering Department of the Tokyo University and was a driving force in the development of commercial 3-D ultrasound equipments in Japan, and indeed worldwide.

In November 1996, with technical assistance from Takashi Okai and Shiro Kozuma from ALOKA Baba published in the Lancet initial experience with real-time processable 3-D, which used a simpler algorithm compared to conventional 3-D rendering. Fetal surfaces were demonstrated in near real-time imaging basing on simple 'accoustic impedance thresholding' to identify fetal surfaces in the amniotic fluid. Image quality was very high and required less expensive computers to make the calculations. The technology was deployed in the SSD-1700 debuted in 1996.

 A brief history of the development of doppler ultrasound in Japan.

* The images of Dr. Toshio Wagai and Shigeru Nakajima courtesy of NHK World Premium, Japan.

** From "Medical Diagnostic Ultrasound: A Retrospective on its 40th Anniversary", reproduced with permission from Dr. Barry Goldberg.

Also referenced from the article "50 years of ultrasonic metal-flaw detection in Japan" (in Japanese).

Images of the Aloka machines courtesy of Aloka® Coporation.

Back to History of Ultrasound in Obstetrics and Gynecology.