Ultrasound. Harris L. Cohen, MD. William H. Moore, MD. Department ..... Arger PH, Mulhern CB Jr, Coleman BG, et al. Prospective analysis of the value of scrotal ...
Commemoration
History of Emergency Ultrasound Harris L. Cohen, MD William H. Moore, MD Department of Radiology State University of New York– Stony Brook University School of Medicine Stony Brook, New York USA
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commemoration such as this one, describing the history and progress of the use of diagnostic ultrasound for a specific clinical area, in this case emergency ultrasonography, is a difficult one. This is true because emergency ultrasonography, like any other commemorated clinical area, owes its information and techniques to the early pioneers of the entire field of diagnostic ultrasound. It was their work that allowed clinicians, scientists, and early sonographic imagers to imagine and then to actually image many areas within the human body.1,2 This is particularly true regarding emergency ultrasonography, which encompasses examinations of many body areas in patients of various ages, with the key unifying theme being the analysis of people with possible clinically emergent conditions. What one defines as an emergency is subjective. Which clinical emergencies are best evaluated by ultrasonography has evolved and continues to evolve with clinical practice trends. Some of the thoughts regarding which emergency situations are best evaluated by ultrasonography and which are not are also affected by local clinical customs and workup methods as well as by who is ordering the imaging examinations and, in some cases, by the practicalities of available machinery and staff.3,4 To simplify things for this short work, we will concentrate on the evolution of 3 areas of emergency clinical analysis that have been helped to a great extent by ultrasound: testicular torsion, ectopic pregnancy, and appendicitis. The historical changes in ultrasound technology and techniques over the last several decades have markedly improved our ability to make accurate and appropriate diagnoses for these abnormalities.5
Advances in Instrumentation Abbreviations AIUM, American Institute of Ultrasound in Medicine; hCG, human chorionic gonadotropin; MSD, mean sac diameter
We thank Barry B. Goldberg, MD, for help in obtaining images and historical information necessary for this Commemoration.
One key force for advancement of sonographic methods and practice has been advances in instrumentation. Briefly, until real-time ultrasonography was readily available for clinical work in the late 1970s to early 1980s, the ability to rapidly analyze areas of the body from multiple angles and in different planes, a necessity for emergency work, was limited. The rigid arm of the contact B-mode ultrasonography machine (Figure 1), first available in the late 1960s, which provided bistable B-scan images (Figure 2), was of limited usefulness for the speed required for use in emergency evaluations. The need to change the transducer arm position to image a few degrees off an object of interest and to change transducers with regard to their frequency or their focal point distance (near field, mid field, or far field) was not conducive to quick examinations. With the introduction of practical clinically available machines with real-time
© 2004 by the American Institute of Ultrasound in Medicine • J Ultrasound Med 23:451–458, 2004 • 0278-4297/04/$3.50
History of Emergency Ultrasound
technology, along with transducers connected by nonrigid wiring (Figure 3), the potential for sonographic analysis of emergency as well as other clinical conditions changed markedly. Bartrum6 described changes in his laboratory’s sonographic work from receipt of their real-time scanner in May 1978 when they examined patients with both static and real-time units. He noted better resolution with his older static scanner but the
Figure 1. Contact B-mode bistable equipment. This early B-mode tandem of instruments making up the ultrasonography unit consists of housing for electronics, a small image screen on the left, and the scanning equipment, including the transducer (arrowhead) hanging off a rigid scanning arm on the right. This is the first commercially available Wright and Meyer scanner sold by Physionics (Longmont, CO). Courtesy of American Institute of Ultrasound in Medicine (AIUM) archives.
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finding of greater pathologic details picked up by the real-time unit. He claimed the death knell for static scanning by the time he obtained an improved real-time unit in the summer of 1979. Real-time units brought speed, resolution, and flexibility. We had a similar experience at State University of New York–Downstate when Morton Schneider was chief of ultrasound and Joshua A. Becker was chairman of radiology. By 1981, typical examinations once taking, for example, 45 minutes by a static scanner to denote, for example, a traumatic perisplenic hematoma or an intra-abdominal abscess were replaced by realtime examinations that could evaluate areas of concern within minutes. Transducers could be moved rapidly from a subdiaphragmatic anterior approach to a coronal longitudinal approach through the patient’s side without the necessity using a static scanner to unscrew and then screw in an appropriate transducer or push and move the machinery for the rigid transducing arm to allow it to be set up to image the patient from a different plane. Before the availability of realtime imaging, ultrasonography was truly more physically laborious. With real-time technology, findings that vary with physiologic states (eg, inspiration/expiration) could be better assessed. The basic analysis for deep venous thrombosis (ie, compressibility of a vein) could be performed. Transvaginal7 and transesophageal transducers were introduced in the mid to late 1980s, allowing real-time imaging of the gynecologic tract and the heart and thoracic aorta, respectively, from a different vantage point (window) and using higher-frequency transducers with better near-field resolution for those examinations. Ectopic pregnancies and aortic dissections could be better imaged. By the 1990s, new hardware and software improvements increased diagnostic capabilities. Cine loop features allowed review and retrieval of key diagnostic images obtained before the frozen image.8 This was particularly helpful in assessing uncooperative or uncontrollable patients, including moving children. Duplex Doppler ultrasonography was replaced by color Doppler ultrasonography, allowing rapid visual assessment of vascular flow. Improvements in color Doppler transducers as well as improvements in flow assessment via color Doppler energy (or power Doppler)9 in the late 1990s improved the ability to analyze vascular flow in vessels as well as organs even in situaJ Ultrasound Med 23:451–458, 2004
Cohen and Moore
tions of slow flow. This helped the analysis of testicular flow, particularly in the child, immensely. The 1990s also introduced harmonic imaging, transducers with electronically controlled focal points, and multihertz transducers whose frequency could be electronically controlled. All these changes helped improve sonographic image quality and the speed of image creation and assessment. Machines and transducers became lighter, easing their movement to the bedside of the critically ill patient. While machinery improved, clinical knowledge of what could and should be looked for increased both via clinical sonographic experience and experience obtained from other imaging modalities. New sonographic windows and assessment techniques were determined with this information.
Testicular Torsion Testicular torsion is the major concern in the evaluation of acute scrotal pain. Although it can occur in fetal life and can be discovered in a neonate, the key period of clinical concern is during adolescence and young adulthood. Torsion usually occurs in the adolescent or young adult from twisting of the spermatic cord within the tunica vaginalis, occluding the blood supply to the testicle and resulting in hemorrhagic infarction. After 2 hours, cells of spermatogenesis are damaged. After 6 hours, they are said to be destroyed. Testicular salvage is said to be 60% to 70% if surgery and detorsion are performed within 24 hours from the acute onset of pain. Salvage is certainly improved by an earlier diagnosis.10 In a review of the early literature regarding ultrasonography of the testicle, including a 1978 work by Sample et al,11 there is little or no information regarding testicular torsion or its analysis. In fact, in 1981, Arger et al12 stated that they were forced to group patients with severe inflammation and torsion together because they “could not distinguish” between the 2 entities. Philips et al13 did describe decreased echogenicity as evidence of a torsed testicle in 1980. Chinn and Miller14 described testicular hyperechogenicity (Figure 4) as evidence of acute torsion in 1985. They mentioned focal hyperechogenicity as evidence of chronic or missed torsion. They cited a 1983 publication by Bird et al,15 which reported 3 cases of hypoechogenicity in acute (
