Advances in ultrasound technology have made it possible to gain higher spatial resolution and even depict nerves with excellent visual quality. In this article, the literature concerning sonography in the diagnosis of carpal tunnel syndrome (CTS) is critically reviewed. We searched Medline for studies on sonography in the diagnosis of CTS and used the reference lists of the articles found. A total of seven studies on the diagnostic capabilities of sonography was found. There were considerable differences in study design. A reliable diagnosis of CTS could be made sonographically, mainly based on an increase in cross-sectional area of the median nerve at the level of the pisiform or hamate bone. However, most studies could not compare the diagnostic capabilities of sonography to those of electrodiagnostic studies, because the latter was applied as the gold standard. Several other reports on the possible extra value of sonography in CTS are mentioned (mass lesions, anatomical variants, rheumatological diseases, renal dialysis-related amyloidosis, surgery, corticosteroid injection). It is probable that sonography will not replace electrodiagnostic studies, but may serve as an additional investigation. To gain further insight into the possible additional value of sonography, it is necessary to examine subcategories of CTS patients in which electrodiagnostic studies are equivocal.

High-resolution sonography is an accurate and easily applied test for the diagnosis of UNE. The authors recommend its use in addition to electrodiagnostic studies because it improves the reliability of the diagnosis of UNE.

Using ultrasonography we found multiple sites with nerve enlargement along the course of the brachial plexus, median, ulnar, and radial nerves in the majority of 21 patients with multifocal motor neuropathy. Sonography and electrophysiologic studies showed more abnormalities than expected on purely clinical grounds. Moreover, sonography revealed nerve enlargement without clinical or electrophysiologic abnormalities.

The aim of this study was to determine possible correlations between the clinical characteristics, electrophysiological features, and sonographic ulnar-nerve diameter in patients with ulnar neuropathy at the elbow (UNE). We prospectively performed clinical, electrodiagnostic, and sonographic studies in 102 patients having either purely sensory signs (35%) or sensorimotor signs (65%) of UNE. Nerve conduction studies had a sensitivity of 78%, and the addition of sonography increased this to 98%. The diagnostic value of both tests was not different among cases with and without motor deficit. Motor studies with recording from the abductor digiti minimi and first dorsal interosseous muscles were equally sensitive for the detection of conduction block or velocity slowing across the elbow, but the combination yielded more positive cases than when only one study was performed. There were modest negative correlations between the electrodiagnostic parameters and the sonographic ulnar-nerve diameter. Electrodiagnostically and sonographically, there were no significant differences between clinically pure sensory and mixed sensorimotor cases of UNE, except for electrodiagnostic findings suggesting loss of motor axons in cases with motor signs. Almost half the patients with only sensory signs had electromyographic evidence of motor axonal loss. We conclude that, although UNE is clinically heterogeneous, the electrophysiological and sonographic findings are fairly consistent despite the clinical manifestations.

One hundred consecutive patients with myasthenia gravis (MG) referred between 1985 and 1989 were analysed for epidemiological characteristics, evolution of early signs, delay in diagnosis, yield of diagnostic tests and effects of treatment. The female to male ratio was 1.6:1.0. Sixteen patients had a thymoma. Ocular MG occurred in 14. Associated autoimmune diseases were found in 15 patients. In 34% of the women and 10% of the men the diagnosis was delayed for more than 2 years. In the first 3 months progression was more rapid in men than in women. Anti-acetylcholine receptor antibodies were found in 94% of the patients with generalized MG and in 29% of the ocular patients. The neostigmine or the edrophonium test was positive in 84% of the generalized and in 60% of the ocular patients. Electromyography was diagnostic in 71% of the generalized and in 42% of the ocular patients tested. Thymectomy was performed in 56 patients (12 with thymomas). Fifty-one per cent were treated with one or more immunosuppressive drugs, at any time. After a mean follow-up of 9.6 years after onset remissions had occurred in 43%, considerable improvement in 25%, moderate improvement in 20% and 12% remained unchanged. There were no deaths due to MG. Thirty-six per cent remained dependent on immunosuppressive drugs. Medication-free remission was most frequent (35%) in the early-onset (< 50 years) group. Side-effects of pyridostigmine were noted in 34% of 99 patients, of prednisone in 65% of 49 patients, and of azathioprine in 54% of 28 patients, but these necessitated stopping the drug in only 1%, 10% and 14% respectively.

High-resolution sonography is capable of depicting peripheral nerves and the brachial plexus. In this study we review the literature on this subject. Normal peripheral nerves have a characteristic echotexture. Most nerves are readily visualized, although this is not always the case with the nerves of the lower extremity. The main pathological changes that can be demonstrated are nerve enlargement and increased hypoechogenicity. In order to demonstrate nerve enlargement, measurements should be performed and compared with a set of reference values. Several neuropathies have been studied by means of ultrasonography. However, many studies concern case reports and show methodological shortcomings. The best studied peripheral neuropathy is the carpal tunnel syndrome in which ultrasonography seems to have an additional value when combined with nerve conduction studies. Nerve enlargement has also been demonstrated in radial neuropathy at the humerus and in ulnar neuropathy at the elbow. The role of sonography in various hereditary and inflammatory neuropathies is uncertain although diffuse nerve thickening could be demonstrated. Further systematic studies are needed to determine the role of sonography in the diagnostic process of the various neuropathies. It would be important to study the subcategories of patients in whom electrodiagnostic studies are normal or show equivocal findings.

Clinical, laboratory and electrodiagnostic studies are the mainstay in the diagnosis of polyneuropathy. An accurate etiological diagnosis is of paramount importance to provide the appropriate treatment, prognosis and genetic counselling. High resolution sonography of the peripheral nervous system allows nerves to be readily visualized and to assess their morphology. Ultrasonography has brought pathophysiological insights and substantially added to diagnostic accuracy and treatment decisions amongst mononeuropathies. In this study the literature on its clinical application in polyneuropathy is reviewed. Several polyneuropathies have been studied by means of ultrasound: Charcot-Marie-Tooth, hereditary neuropathy with liability to pressure palsies, chronic inflammatory demyelinating polyneuropathy, Guillain-Barré syndrome, multifocal motor neuropathy, paraneoplastic polyneuropathy, leprosy and diabetic neuropathy. The most prominent reported pathological changes were nerve enlargement, increased hypo-echogenicity and increased intraneural vascularization. Sonography revealed intriguingly different patterns of nerve enlargement between inflammatory neuropathies and axonal and inherited polyneuropathies. However, many studies concerned case reports or case series and showed methodological shortcomings. Further prospective studies with standardized protocols for nerve sonography and clinical and electrodiagnostic testing are needed to determine the role of nerve sonography in inherited and acquired polyneuropathies.

The role of ultrasonography in UNE seems promising but could not be firmly established. More prospective studies are needed, and we make several recommendations for further research.