Ultrasound of nerve and muscle - new technology

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Research from Clin Neurophysiol. 2004 Mar;115(3):495-507.

Ultrasound of nerve and muscle.

FO, Cartwright MS, Wiesler ER, Caress J.

Department of Neurology, Wake Forest University School of Medicine

Medical Center Boulevard, Winston-Salem, NC 27157-1078, USA.

Over the last two decades, ultrasound has developed into a useful

technology for the evaluation of diseases of nerve and muscle. Since it

is currently not used at by the majority of clinicians involved in

diagnosis or care of patients with neuromuscular disorders, this review

briefly describes the technical aspects of ultrasound and its physical

principles. It relates normal muscle anatomy and movement to ultrasound

images in the axial and sagittal planes and follows with a discussion of

ultrasound findings in chronic muscle disease. These include evident

atrophy and the loss of the hypoechoic architecture of normal muscle

tissue. It highlights evolving uses of the technique to measure other

pathologic changes in disease including altered muscle dynamics. With

high-resolution instruments nerve imaging has now become standard, and

the relationships of median nerve anatomy and observations of static and

dynamic images from ultrasound are reviewed. Changes seen in carpal

tunnel syndrome include significant increases in the cross-sectional

area of the nerve just proximal to the site of compression, loss of

hyperechoic intensities within nerve, and reduced mobility. Preliminary

use of the technique for the study of other nerves is reviewed as well.

Ultrasound is an ideal tool for the clinical and research investigation

of normal and diseased nerve and muscle complementary to existing

diagnostic techniques. As the technology continues to evolve, it will

likely assume a more significant role in these areas as those most able

to exploit its potential, clinical neurophysiologists and neuromuscular

clinicians, incorporate its use at the bedside.