Musculoskeletal ultrasound: a technical and historical perspective

Ronald Steven Adler

Affiliation and address for correspondence
J Ultrason 2023; 23: e172–e187
DOI: 10.15557/JoU.2023.0027
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During the past four decades, musculoskeletal ultrasound has become popular as an imaging modality due to its low cost, accessibility, and lack of ionizing radiation. The development of ultrasound technology was possible in large part due to concomitant advances in both solid-state electronics and signal processing. The invention of the transistor and digital computer in the late 1940s was integral in its development. Moore’s prediction that the number of microprocessors on a chip would grow exponentially, resulting in progressive miniaturization in chip design and therefore increased computational power, added to these capabilities. The development of musculoskeletal ultrasound has paralleled technical advances in diagnostic ultrasound. The appearance of a large variety of transducer capabilities and rapid image processing along with the ability to assess vascularity and tissue properties has expanded and continues to expand the role of musculoskeletal ultrasound. It should also be noted that these developments have in large part been due to a number of individuals who had the insight to see the potential applications of this developing technology to a host of relevant clinical musculoskeletal problems. Exquisite high-resolution images of both deep and small superficial musculoskeletal anatomy, assessment of vascularity on a capillary level and tissue mechanical properties can be obtained. Ultrasound has also been recognized as the method of choice to perform a large variety of interventional procedures. A brief review of these technical developments, the timeline over which these improvements occurred, and the impact on musculoskeletal ultrasound is presented below.

ultrasound; musculoskeletal; technical; historical
Video 1. Rotator cuff repair. Three-month post-operative long-axis images of supraspinatus tendon repair. Grayscale image of the repair depicted in the upper right. Upper left shows individual frames of enhancement from which a time-intensity curve can be derived. The lower center image is a maximum pixel intensity image, showing time history of any pixels that have seen contrast. Pixel intensity is a measure of local vascularity. The degree of vascularity depicted with contrast far exceeds what would be demonstrated using conventional Doppler techniques