Dr. G. D. Ludwig’s first ultrasonic scanning equipment. During his service at the Naval Medical Research Institute in Bethesda, Maryland, Dr. Ludwig concentrated on the use of ultrasound to detect gallstones and other foreign bodies embedded in tissues, an approach similar to the detection of flaws in metal.EndFragment
History of Ultrasound in Medicine
Stage of the First Attempts (<1952)1942 Dussik: First attempts to use ultrasound transmission in medical diagnostics (“hyperphonography” of the cerebral ventricles).
1949 Keidel: Volume measurement of the heart (transmission-technique).
1949 Ludwig and Struthers: use of a pulse-echo-device (material testing device).
1950 Wild and Reid: Tissue characterization with ultrasound.
1951 Wagai: Diagnosis of gall stones and cancer via waterbath scanner.
1960 Satomura: Transcutaneous Doppler sonography of cervical and peripheral vessels.
History of Ultrasound in MedicineClinical Adoption (>1950)
1952 Howry and Bliss: First two-dimensional ultrasound image sector scanner (waterbath).1952 Wild and Reid: Two-dimensional imaging of body structures, first endoprobes.1953 Edler and Hertz: Echocardiography (TM-mode).1954 Leksell: Echoencephalography (A-mode).1955 Howry and Bliss: First compound scanner (waterbath).1956 Mundt and Hughes: Ophthalmography (A-mode).1957 Donald and Brown: First contact-compound scanner.1958 Baum and Greenwood: Ophthalmography (B-mode, Compound-scanner).1961 von Ardenne and Millner: Focoscan for horizontal slices (C-mode).1964 Schentke and Renger: Tissue characterization with A-mode technique.1965 Krause und Soldner: First automated real-time scanner (Vidoson).1965 Holländer: Real time in Obstetrics and Gynecology.1966 Strandness Jr.: First commercially available CW-Doppler equipment in the Western hemisphere.1967 Watanabe: Transrectal scanning of the prostate.1969 Rettenmaier: Real-time scanning of the abdomen.1969 Kratochwil: First biopsy transducer for a compound scanner.1972 Greene: High performance ultrasonic camera (acoustical holography).1972 Holm: First biopsy transducer for real-time scanner.
1973 Carlsen and Garrett: Gray scale technique.
1974 Baker and Strandness: First prototype of duplex system.
1974 ADR 2130: First commercially available linear array scanner. 1986 Aloka Quantum: First color coded duplex-sonography.
History of Ultrasound in Medicine
1793 Spalanzini postulates a sixth sense in bats, later assumed to be an “ultrasound-sense“ (1920), proven not before 19391842 Doppler detects the relative frequency shift of moving sources (redshift of double stars) – the Doppler-effect.
1877 Strutt describes the physical principles of sound, “The Theory of Sound”.1880 The Curie-brothers detect the piezoelectric effect.1912 Behm and – independently – Richardson invent the sonar.1916 Langevin and Chilkowsky construct the first ultrasound generator and the equipment for underwater detection of submarines.
1929 Sokolov develops the nondestructive ultrasound test of different media.1929 Wood, Loomis, and Johnson start frst studies of ultrasound bioeffects.1936 Gohr and Wedekind discuss ultrasound examination of inner organs.1939 von Pohlmann introduces ultrasound in therapy.
Pioneers of Medical Ultrasound
K. Th. Dussik, neurologist in Vienna, was the first physician who tried to use ultrasound for diagnostic purposes in medicine.
In 1942 he published a method of depicting the cerebral ventricles named “ ypersonography”: the transmitter and receiver were placed at opposites sides of the skull in fixed relations. The intensity of the signal was recorded on a film.
By moving the probe line by line across the skull, a two-dimensional image was created, giving information about changes in absorption of ultrasound (in analogy to classical x-ray).
Twins (bistable compound scan)
Compound scan, gray scale (1976)
Transverse scan of the abdomen (1999)
Transducer RA 1
A-mode of the liver
Real time (Combison 100, Kretz), 1980
3D image of a fetus (1999)
From A-Mode to B-ScanThe one-dimensional A-mode, introduced in 1949 by Ludwig to detect gallstones and adopted in 1954 by Leksell as “echoencephalography”, never seemed suitable for the diagnosis of complex regions, like the abdomen. Instead, an imaging modality was necessary for topographic orientation. Two steps lead to the development of two-dimensional ultrasound imaging:
1. The echoes were displayed as dots with modulated brightness on the nearly invisible time-base-line (Brightness-mode).
2. Multiple scan lines were arranged to form a two-dimensional plane.
The transducer was moved manually in the beginning (compound scan). Because of the low sensitivity of the probes, the region of interest was scanned several times in various directions to get echoes also from weak reflectors (Howry, 1952). Position encoders in the scanning arm were used for the exact geometric localization of the echoes within the image. The echoes were displayed on a storage oscilloscope. Thus, the composition of a single ultrasound image needed several seconds at least; movement of the areas scanned lead to distortions.
Doppler-SonographyDiagnostic ultrasound gained new perspectives from the use of “Doppler-Sonography”, named after the Austrian physicist Christian Doppler (1803–1853). He discovered that the frequency of waves – including sound waves – will shift, when the origin of the waves and the observer will move relative to one another.
For example, if a source of sound of a constant pitch is moving toward an observer, the sound seems higher in pitch, whereas if the source is moving away, it seems lower. Correspondingly, the frequency of diagnostic ultrasound (about 1–20 MHz) will change to a higher or lower pitch when reflected or scattered at moving corpuscular elements within a living body, especially blood cells. Examining blood vessels with 2–8 MHz ultrasound, the shift between emitted and reflected sound waves is approximately in an audible range of 50 Hz–20 kHz. Knowing the frequency shift and the angle of insonation, one can calculate the velocity of the blood low. Variations between systolic and diastolic blood flow patterns are specific for certain blood vessels. A change of these proportions or a very high or very turbulent low indicate a vessel stenosis. A missing ultrasound Doppler shift would be typical for an occlusion. In veins not only the spontaneous but also the augmented low patterns are relevant – for instance after compression of more distant veins. Experienced sonographers make their diagnoses by listening to the ultrasound Doppler-low signals. Documentation either as a graphical curve or, after “Fast Fourier Transformation” (FFT), as a time- frequency spectrum.
In duplex-sonography a single ultrasound probe combines pulsed Doppler-sonography with B-mode sonography to enable low-measurements in a visually defined region of interest.
In color-coded duplex sonography a net of Doppler-sonographic sample volumes is virtually spread over the B-mode picture. Average Doppler shifts are coded in various color shades and are superimposed to the B-mode picture of an organ, with low velocity and low direction being displayed in different color hues (Baker and Strandness 1974). This method makes it easy to find blood vessels within tissues and to look for best Doppler- sonographic measurement points, for instance behind cardiac valves or in stenotic vascular regions.
The machine, constructed by Dussik and his brother
A-mode measurement of the 3th ventricle
Construction of the two-dimensional ultrasound image with a hand-held probe on a storage screen. Note the different scanning lines (right-compound scanner)
First Medical Applications
J. Donald (Glasgow) constructed the first contact-compound-scanner in 1957. Instead of immersing the patient in water, ultrasound gel was placed between the transducer and the body. Now the ultrasound probe could be moved manually on the skin.
Donald diagnosed twins, triplets, hydramnios, and fetal anomalies (hydrocephalus).
He propagated the use of a full bladder as an acoustic window. The contact-compound-scanner became the basis for large-scale use of diagnostic ultrasound in medicine.
Position and direction of the transducer were calculated using position encoders in the scanning arm. The echoes were usually displayed on a storage oscilloscope (static system).
Color-coded display of bypass-stenosis
Hypersonogram of the 3rd ventricle
K. Th. Dussik
Principle of Doppler-sonography
Initially all echoes beyond a certain (adjustable) threshold were displayed as uniform bright dots (bistable system). Around 1973, the gray scale technique was introduced in compound scanners: the echoes were displayed according to their strength.
Pioneers of Medical Ultrasound
In 1949 G. Ludwig (Pennsylvania) presented the first application of a pulse-echo-device (echo-ranging) in medicine. For the detection of gallstones he used a device that was originally designed for nondestructive material testing (A-mode). Ludwig reported an accuracy of around 85% in vivo.
Another one of his important works was the exact measurement of the velocity of ultrasound in different types of soft tissues.
Two-dimensional B-scanning Mechanical Systems
Real time system, mechanically The Vidoson 635 (Siemens), developed by R. Soldner, was the first fast scanning machine (real-time). The ultrasound beams of rotating transducers were reflected as parallel arranged beams into the body using a parabolic mirror. An image frequency of 15/sec as well as gray scale capability enabled a dynamic examination.
Continuous-wave Doppler-sonography (about 1978)
First contact-compound-scanner. The probe was moved by hand in direct contact to the skin.
For the following years mechanical sector probes became standard in ultrasound diagnostics. Even today, this method is being used for particular applications. As an example, the sector scanner Combison 100 (Kretz, 1977) used 5 rotating transducers. Always the transducer passing the window (directed to the body) was activated by a magnet, forming a sector image.
A-scan of the bladder, before (above) and after miction
Ultrasound velocity in different
The advanced system RA 1 (Diasonics, 1980) used 3 simultaneously rotating transducers, to form a combined, large field image
From Bistable Images to Gray Scale
The first ultrasound images were "black and white": the echoes above a (adjustable) threshold were displayed as uniformly bright dots on a dark background (bistable). Weak echoes below the threshold were lost. Information by complimentary A-mode were necessary, eg, to distinguish between solid and cystic lesions.
The introduction of the gray scale technique was an important step forward: Now the echoes were displayed as dots varying in brightness according to the intensity of the reflected echoes. Modulated brightness was an integral part of the real-time scanners from the beginning. In compound scanners, using scan converters, gray scale imaging was introduced about 1973. Further technical improvements, as electronic focusing of the ultrasound beam, suppression of artifacts, digitalization, harmonic imaging, and the ever increasing speed of data processing resulted in a remarkable improvement of the image quality. The integration of the Doppler-technique into the B-mode image leads to duplex and triplex techniques. The 3D and 4D-depictions and the development of contrast agents characterize the standards of the beginning of this century.
Doppler-SonographyFields of ApplicationObstetrics: Registration of fetal heart beats and umbilical cord vessels (Kratochwil, 1967; Weber and Stockhausen, 1967).Peripheral arteries: First application, 1959 (Satumura). Measurements of systolic blood pressure at the limbs, detection and quantitative evaluation of a peripheral arterial circulatory insufficiency (Schoop and Levy, 1969; Bollinger, Mahler, and Zehender, 1970).
Peripheral veins: Detection of thromboses and valvular (Bollinger and Mahler, 1968).Extra- and intracranial arteries: Indirect Doppler-sonography via periorbital arteries (Müller, 1972). Direct insonation and differentiation of the arteries of the neck (Büdingen, von Reutern, and Freund, 1976). Examination of intracranial arteries (Aaslid, 1982). Experimental use of diagnostic ultrasound for supporting thrombolysis after stroke (Alexandrov, 2002).Cardiology: Intracardial low measurements by Seipel (end of the 1960s), Doppler-echocardiography(Hatle and Angelsen, 1982).
From Compound Scanning to Real Time
Originally, the compound scanners had disadvantages: A rather complex technique for the correct arrangement of the echoes was needed and – not least – no real-time viewing was possible, as the composition of the images was slow and movements of the patient or the organs scanned produced severe artifacts. Furthermore, the images gained by manually operated compound scanners were hard to reproduce. These disadvantages were partially overcome by the development of automatic scanners. These mechanical or electronic devices worked faster and the results had better reproducibility.
The first commercially available real-time scanner was the Vidoson (Siemens). The pulses of two or three rotating transducers within a water path were reflected by a parabolic mirror, leading to 15 cm of parallel shifting of the ultrasound beam.
The real-time technique made its way, finally, because of its automatic, reproducible, and fast image construction. Dynamic examinations enabled quick examinations and direct observation of movements.
The further technical development lead to mechanical and electronic scanners with parallel or sector scanning, which are still in use today.
Transverse scan of the abdomen Compound scanner, gray scale (1975)
B-scan image of the neck
First Medical Applications
D. Howry (Denver) was the first pioneer who in 1952 presented two dimensional ultrasound images in cooperation with the engineer R. Bliss. The examination was carried out with the patient sitting in a water-filled tub. For examinations of the neck the patient therefore had to be immersed in the water almost to the tip of the nose. The scanner repeatedly made semicircles around the patient.
Together with Joseph Holmes he examined mainly the organs of the abdomen: the liver, the spleen, the kidneys and the urinary bladder.
Systolic blood pressure
Principle of compound scanners
A-mode was the first ultrasound method, used for medical diagnosis. The piezoelectric transducer emits very short ultrasound pulses (1 ms), periodically (PRF 0.3–10.0 kHz), which travel through the object. Each pulse results in horizontal deflections of the electronic beam of a cathode ray tube on a fluorescent screen indicating the time that the pulse needs to travel through the object. The echoes are displayed as vertical deflections of the electronic beam on the screen. The position of an echo indicates the distance of its source (echo-ranging), the amplitude its intensity. Echo-ranging devices were first developed as sonars for navigation 1912. The same principle was used for non- destructive material testing since 1929. Ludwig and Struthers adopted such a device for medical diagnostics, 1949. For many years the one-dimensional A-mode was especially used in ophthalmology and neurology. But for an examination of more complex structures (eg the abdomen), the development of two-dimensional imaging was necessary.
Two-dimensional B-scanning Mechanical Systems
Compound-scanning Compound-scanning was the original way to create two-dimensional ultrasound images. A single-element transducer was moved manually in direct skin contact across the selected plane in multiple directions by sweeping the probe repeatedly thru a certain sector.
Echoencephalogram (normal finding)
Combison 202 Kretz, 1979 - scheme of the scanner arm
Bistable image gray scale image transverse scan of the
upper abdomen, pancreatic cancer
University of Colorado Experimental Unit, intended for cardiac work.
Early ultrasonic ophthalmoscopic equipment used by Dr. Gilbert Baum, designed and built by Baum and Dr. Ivan Greenwood. For the Baum “second generation” B-mode scanner for the eyes, ultrasonic coupling was provided by water bath and goggle. This compound scanner detected tumors, cysts, and other lesions in the back of the eye. Ophthalmic scanning was performed with the eye open in a tank of normal saline. This inflatable-seal mask provided the interface between the patient and the tank. A hand-held gimbal mechanism was used to calibrate both the scanning and signal processing system in the ophthalmic scanner. The reflecting surface was a glass plate that could be rotated through various angles to calibrate the scanner angular sensors as well as to calibrate the off-angle transducer response.
Face seal for ophthalmic ultrasound scanner
Hoffrel Instruments Inc. Ultra-Sonoscope Model 101
An A- and B-Mode Mechanical Scanner.
Compound immersion scanner with water tub.
Developed by Douglass Howry and his team at the University of Colorado Medical Center, this compound scanner included a large, water-filled water tank. The transducer moved back and forth along a four-inch path, while the carriage on which the transducer was mounted moved in a circle around the tank, producing secondary motion necessary for compound scanning.
University of Colorado Experimental System
Instrument used to determine brain midlines.
A-mode eye and breast scanner.
Sperry Reflectoscope Pulser / Receive Unit 10n
A- and M-mode instrument.
This is an example of the first instrument to use an electronic interval counter to make axial length measurements of the eye. Individual gates for anterior segment, lens and vitreous compartment provided accurate measurement at 10 and 15 MHz of the axial length of the eye. This concept was the forerunner of all optical axis measurements of the eye, which are required for calculation of the appropriate intraocular lens implant power following cataract extraction. This instrument was developed by Dr. D. Jackson Coleman and Dr. Benson Carlin at the Department of Ophthalmology, Columbia Presbyterian Medical Center.
Sonoray Model No. 12 Ultrasonic Animal Tester
An intensity-modulated B-mode unit designed exclusively for animal evaluation. The instrument is housed in a rugged aluminum case with a detachable cover which contains the cables and transducer during transportation. The movable transducer holder on a fixed curve guide was a forerunner of the mechanical B-scan ultrasonic equipment.
Smith-Kline Fetal Doptone
Pharmaceutical manufacturer Smith Kline and French Laboratories of Philadelphia entered the medical instrumentation business in 1961. Using the continuous-wave Doppler prototype developed at the University of Washington, they built and marketed in 1966 a Doppler instrument, called the Doptone, that was used to detect and monitor fetal blood flow and heart rate.
A-Mode used in ophthalmology and neurology to determine brain midlines.
Working in collaboration with Branson Instruments of Stamford, CT, SmithKline introduced the Ekoline 20, an A-mode and B-mode instrument for echoencephalography, in 1963. When the B-mode was converted to M-mode in 1965, the Ekoline 20 became the dominant instrument for echocardiography as well and was the first instrument available for many start-up clinical diagnostic ultrasound laboratories.
Smith-Kline Ekoline 20
Siemens-Schnittebene Usip 10-W245s W-Ne,818
Dr. J. S. Lehman with an early Physionics bi-stable B-scan ultrasound instrument.
Static B-mode scanning arm.
Physionic Traverse Table Mod Tt-661 Ser. 718
University of Colorado Medical Center 13437 with Polar Coordinate Indicator
This modified Tektronix Type 561A Oscilloscope is an example of a storage oscilloscope that gives the ability for M-mode. This A- and M-mode bi-stable static scanner was used for cardiac work.
Bi-stable static scanner.
Physionic Eng Inc VDA-631
Real-time ultrasound scanner.
The advent of real-time scanning in the mid-1960s revolutionized diagnostic ultrasound because it allowed real anatomical features to be seen instantaneously. All portions of the body could be scanned rapidly and thoroughly. This EkoLife Scanner was used to scan the abdomen in diagnostic applications associated with obstetrics and gynecology.
Life Instruments Water Bath Breast Scanner
This system features large dual monitors with single step, freeze frame or synchronized sequencing modes, and could generate videotaped images. The image replay system was able to show both breasts simultaneously.
Oscilloscope modified for ultrasonic scanning.A- and M-mode scanner.
Tektronix Type Rm564 Storage Oscilloscope
ADR of Tempe, AZ began delivering ultrasound components to major equipment manufacturers in 1973. Linear array real-time scanners, which began to be manufactured in the mid-1970s, provided greater resolution and more applications. Gray scale, with at least ten shades of gray, allowed closely related soft tissues to be better differentiated. This machine was widely used in obstetrics and other internal medicine applications.
ADR - Model 2130
Sonometrics Systems Inc., Ny Br-40v
The first commercially available ophthalmic B-scan, this system provided both linear and sector B-scans of the eye. The patient was examined in a water bath created around the eye by use of a sterile plastic ophthalmic drape with a central opening. Both A-scan and B-scan evaluations were possible with manual alignment of the transducer in the water bath. The instrument was developed at the Department of Ophthalmology, Columbia Presbyterian Medical Center by Dr. D. Jackson Coleman, working with Frederic L. Lizzi and Louis Katz at the Riverside Research Institute.
Unirad static B-scanner used with a scan arm.
Unirad GZD Model 849
Bioengineering-University of Washington
Introduced in 1977, this computer was used for early color Doppler experiments. Z2 “microcomputers” were used for a variety of data acquisition and analysis applications, including planning combat missions for the United States Air Force and modeling braking profiles for the San Francisco Bay Area Rapid Transit (BART) system during actual operation.
Cromenco Z2 Computer System
This AFE is a 43-pound off-the-shelf version of an ATL 400 medical ultrasonic imaging system, which was modified for space shuttle compatibility by engineers at the Johnson Space Center in order to study the adaptations of the cardiovascular system in weightlessness. Its first journey to space was on the space shuttle Discovery in 1985 and its last on the Endeavour in 1992. The AFE generated a two-dimensional cross-sectional image of the heart and other soft tissues and displayed it in video format at 30 frames per second.
Astronauts Marsha Ivans [top] and Bonnie Dunbar [right] use the AFE to take an echocardiogram of fellow astronaut, David Lowe, on the Columbia in 1991.