Getting Started with Ultrasound

Contents:  Ultrasound Basics               

                            Introduction

                            Examination of Tissues

                            Understanding Sonographic Pictures

                            Scanning Podiatric Pathology

                            Diagnostic Ultrasound & Podiatric Pathology

                            Summary

                            Ultrasound Scanners

                            HydroStep™ Standoff System

                            Sound-Seal™ Protective Film Dressing

                            Wound-Mapping® Ultrasonic Assessment Method

INTRODUCTION

Ultrasound (sonar) has its roots in the military, and in brief, it was used in submarines for detecting the surface and shape of the ocean floor. In medicine, B-mode or B-scan simply means the scanning of a part of the human body. Such a scan is either live, where the image is seen on a video screen and printed at the time it is acquired, or scanned now and compiled later into and image for study. (The later was an earlier method to produce an image for study.) This is 1998 CPT code # 76880- Echography, extremity, non-vascular, B-scan and/or real time with image documentation.

M-mode indicates that there is the recording of MOTION, such as that of an ultrasound of the heart or a fetus. Briefly, if one takes a scan and produces a picture of a fetus within the mother, we could not tell if it was alive at that moment. However, a B-mode image along with an M-mode image recorded at that same time will show that the fetus was alive at that point in time.

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Examination of Tissues

As ultrasound waves are sent into the tissues, part of the sound is reflected back to the probe while others continue into deeper tissues. Much of this is dependent on the frequency of the probe, which is being used. Unlike the probes used for physical therapy which are designed for deep heating of tissues, diagnostic ultrasonography probes cause no heating or tissue damage. For diagnostic musculoskeletal ultrasound a 7.5mhz probe is used. This 7.5mhz probe produces an image that is 4.5cm long and penetrates into the tissues 7cm deep at maximum. This 7.5mhz probe known as a "high resolution extremities probe" is used for carpal tunnel syndrome, torn rotator cuff, and has many excellent podiatric applications. Other probes such as the 5.0mhz are for deeper structures (used for the examination hip, knee, and spine), and 3.0mhz for still deeper structures. Ultrasound can be used to examine the arterial/venous system, heart, pancreas, urinary system, ovaries, spinal cord, and more. Ultrasound is excellent for diagnosing cysts in soft tissue because usually they contain fluid. Ultrasound is safe during pregnancy. Ultrasound uses no radiation unlike x-rays, Cat Scans and other such modalities.

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UNDERSTANDING Sonography PICTURES

For most, the first contact and initial examination performed by one not familiar with diagnostic ultrasound will require some study. We would like to see a picture such as that of an MRI or CAT scan. However, the physician quickly realizes that the video or picture that is being studied is a small section of tissue. Examples of Ultrasound scans like those that you will encounter are found in the Case Study and Other Scans pages on this web site.

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An advantage of diagnostic ultrasound besides its safety, is the ability to perform live active and/or passive range of motion studies. The ability to move a particular part of the anatomy, observe and record motion studies such as partial or complete tendon, muscle, and ligament tears should not be understated. To enable the physician to diagnose cases, record, and document these studies increases the likelihood of better treatment and end result. Please note that MRI, CAT scans, and x-rays all do not allow for motion studies. Although diagnostic ultrasound is not intended to eliminate those studies, one should realize that the cost of an ultrasound is about one tenth that of an MRI. Should the physician receive satisfactory information from the musculoskeletal ultrasound and avoid the need of an MRI scan, the patient and/or insurance companies benefit in those savings.

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DIAGNOSTIC ULTRASONOGRAPHY

PODIATRIC PATHOLOGY

The foot, perhaps more than any other area of the body receives a lot of injury, stress, and strain. The reaction of tissue to trauma is the same throughout the body causing pain, swelling and the like. Trauma and resulting swelling and inflammation cause an influx of fluid to a particular area. In diagnostic musculoskeletal ultrasound, scanned areas of inflammation appear darker or hypoechoic due to the sound wave passing through the fluid filled inflamed area.

Pathology in which ultrasound will aid the podiatric physician in the office setting includes:

As stated earlier ultrasound studies require the physician to place the probe on an area in the transverse (frontal) plane or the longitudinal (sagittal) plane. Knowledge anatomical structures and their relative position is a must (i.e. what is superior, inferior, proximal, or distal).

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SUMMARY

Musculoskeletal ultrasonography for the podiatric physician should be viewed as an additional tool to aid in the diagnosis and treatment of musculoskeletal injury and disease. Podiatrists whether their practice is basic podiatric medicine, surgically oriented, sports medicine, podo-pediatrics or whatever one’s practice population, your patients can benefit from this diagnostic tool.
Podiatric physicians should utilize and take advantage of all the modern modalities, improve our skills, and continue to grow within the medical community. 

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