Naoko Takamatsu

Thinning of cervical nerve roots and peripheral nerves in ALS as measured by sonography.

OBJECTIVE Progressive atrophy and loss of motor axons is a hallmark of amyotrophic lateral sclerosis (ALS). Limited sonographic data are available on potential detection of atrophy of peripheral nerves and nerve roots in ALS. METHODS Patients with either definite or probable ALS and control subjects underwent sonographic evaluation of the cervical roots (C5, C6, and C7) and peripheral nerves (median and ulnar nerves) on the right. These diameters and cross-sectional areas (C6, median, and ulnar nerves) were compared. RESULTS The diameters and cross-sectional areas were consistently smaller in ALS than in controls. No correlation was present between the sonographic parameters and the disease severity, disease duration, age, or gender. The overall sensitivity and specificity tended to be greater in the cervical nerve roots than in the peripheral nerves. CONCLUSIONS This study shows atrophy of cervical nerve roots and peripheral nerves in ALS detected by sonography. Cervical nerve roots might be more appropriate to detect motor axon loss than peripheral nerves. SIGNIFICANCE Sonographic evaluation of nerve roots and peripheral nerves may be a useful disease marker in ALS to confirm the diagnosis and to potentially monitor the disease progression.

High-resolution sonography detects inflammatory changes in vasculitic neuropathy

In vasculitic neuropathy, nerve biopsy is the gold standard for diagnosis.6 However, nerve biopsy is often limited to pure sensory nerves to avoid complications, so that morphological assessment of the clinically affected nerves is sometimes impossible. Recent progress has permitted the noninvasive visualization of peripheral nerves by sonography.2 We report a patient with vasculitic neuropathy assessed by this means. A 60-year-old woman with a 2-year history of malignant rheumatoid arthritis on a low dose of oral steroids suddenly developed weakness and pain in all extremities. Neurological examination revealed diffuse, distal-dominant weakness and sensory loss, especially in the peroneal and ulnar distribution (complete bilateral foot drop and intrinsic hand-muscle weakness). Electrodiagnostic studies revealed asymmetric motor and sensory axon loss with normal conduction velocities [distal compound muscle action potential (CMAP) amplitudes on the left were tibial, 0.9 mV; peroneal, 0.1 mV; median, 2.2 mV; and ulnar, 3.4 mV with conduction block in the forearm; on the right they were median 4.1 mV, and ulnar 1.6 mV; sural sensory nerve action potentials (SNAPs) were absent on both sides]. Nerve biopsy was not performed at the patient’s request, but skin biopsy from the erythematous calf region confirmed the diagnosis of vasculitis, presumably associated with her malignant rheumatoid arthritis. Sonography of the right ulnar nerve on day 7 from the onset showed a hypoechogenic epineurial region as well as increased nerve diameter suggestive of inflammatory infiltrates and edema of the epineurium (Fig. 1A,B). Further assessment revealed diffuse thickening of the peripheral nerves including both median, left ulnar, and both tibial nerves and the cervical nerve roots with variable severity. Two weeks after initiating intravenous steroid infusion followed by high-dose oral steroids, her neuropathic pain improved significantly and the sonographic image of the right ulnar nerve appeared less edematous, with its diameter close to normal. Sonographic findings in the peripheral nervous system have been reported in various neurological diseases, including entrapment neuropathies, generalized demyelinative neuropathies, and focal nerve tumors.2–5 The nerve thickening typically observed in carpal tunnel syndrome FIGURE 1. Longitudinal imaging of the right ulnar nerve (proximal forearm). The normal echogenic image of a peripheral nerve includes outer hyperechogenic structures (epineurial sheath) within which are multiple longitudinal hyperechogenic and hypoechogenic regions representing connective tissues and neuronal fascicles, respectively (not shown). Our patient showed (A,B: before and after steroid therapy) focal hypoechogenic epineurial regions (arrowhead) and increased diameter (5.5 mm, normal 3.0) and area (23 mm, normal 8). The nerve borders are outlined by the arrows. The nerve area declined to 10 mm after steroid therapy (B). Note that the longitudinal structure lacks blood flow (the box in B indicates a region of interest for Doppler sonography).

Neurogenic and Myogenic Diseases: Quantitative Texture Analysis of Muscle US Data for Differentiation

Purpose To assess the multiple texture features of skeletal muscles in neurogenic and myogenic diseases by using ultrasonography (US). Materials and Methods After institutional review board approval, muscle US studies of the medial head of the gastrocnemius were performed prospectively in patients with neurogenic diseases (n = 25 [18 men]; mean age, 66.0 years ± 12.3 [standard deviation]), in patients with myogenic diseases (n = 21 [12 men]; mean age, 68.3 years ± 11.5), and in healthy control subjects (n = 21 [11 men]; mean age, 70.5 years ± 8.4) between January 2013 and May 2016. Written informed consent was obtained. Muscle texture parameters were obtained, and five algorithms were used to classify the groups. Results The neurogenic and myogenic disease groups showed higher echo intensities than the control subjects. The histogram-derived texture parameters had overlaps between the neurogenic and myogenic groups and thus had a low discrimination rate. With assessment of more classes of texture parameters, three groups were correctly classified (100% correct, according to four of five classification algorithms). Tenfold cross validation showed 93.5%-95.7% correct classification between the neurogenic and myogenic groups. The run-length matrix, autoregressive model, and co-occurrence matrix were particularly useful in distinguishing the neurogenic and myogenic groups. Conclusion Texture analysis of muscle US data can enable differentiation between neurogenic and myogenic diseases and is useful in noninvasively assessing underlying disease mechanisms.

Intramuscular dissociation of echogenicity in the triceps surae characterizes sporadic inclusion body myositis

Differential diagnosis of sporadic inclusion body myositis (s‐IBM) and polymyositis (PM)/dermatomyositis (DM) is difficult and can affect proper disease management. Detection of heterogeneous muscular involvement in s‐IBM by muscle sonography could be a unique diagnostic feature.

Cervical root sonography to differentiate multifocal motor neuropathy from ALS

To explore suggestive evidence of focal proximal demyelination in multifocal motor neuropathy (MMN) without overt evidence of conduction block, we conducted sonographical assessment of cervical nerve roots in 9 MMN patients, 22 ALS patients, and 17 control subjects. The mean diameters of the C5 and C6 roots in MMN patients were significantly larger than those in ALS and controls, especially on the clinically dominant side. Although non-specific, sonography can be a potentially useful diagnostic procedure to support the diagnosis of MMN, even when overt conduction block is lacking.

Which muscle shows fasciculations by ultrasound in patients with ALS

The purpose of the present study was to elucidate the relative frequencies of fasciculations assessed by sonography in a large number of muscles in patients with amyotrophic lateral sclerosis (ALS). The patients diagnosed as having ALS were retrospectively assessed by muscle sonography. The frequencies of having fasciculations were compared among the 15 muscles and the subtypes according to the initially affected body region. Overall, approximately half of the muscles had fasciculations (48.8%), in the average of 11.4 muscles per patient. The frequency of fasciculations tended to be lower in the patients with longer disease durations upon testing. Biceps brachii had the highest frequency, followed by extensor digitorum communis, whereas sternocleidomastoid and rectus abdominis had the lowest frequencies. The frequencies of fasciculations were similar among the clinical subtypes. In conclusion, in patients with ALS, fasciculations were detected most frequently in proximal arm muscles by sonography, whereas truncal muscles had lower frequencies. Fasciculations tended to be less evident in the advanced disease stage, possibly reflecting muscle degeneration. Appropriate selection of muscles to observe fasciculations is important for diagnosis of ALS.

Sonographic evaluation of peripheral nerves in subtypes of Guillain-Barré syndrome

BACKGROUND Sonography of peripheral nerves can depict alteration of nerve sizes that could reflect inflammation and edema in inflammatory and demyelinating neuropathies. Guillain-Barré syndrome (GBS). Information on sonographic comparison of an axonal subtype (acute motor [and sensory] axonal neuropathy [AMAN and AMSAN]) and a demyelinating subtype (acute inflammatory demyelinating polyneuropathy [AIDP]) has been sparse. MATERIAL AND METHODS Sonography of peripheral nerves and cervical nerve roots were prospectively recorded in patients with GBS who were within three weeks of disease onset. RESULTS Five patients with AIDP and nine with AMAN (n=6)/AMSAN (n=3) were enrolled. The patients with AIDP showed evidence of greater degrees of demyelination (e.g., slower conduction velocities and increased distal latencies) than those with AMAN/AMSAN. The patients with AIDP tended to show enlarged nerves in the proximal segments and in the cervical roots, whereas the patients with AMAN/AMSAN had greater enlargement in the distal neve segment, especially in the median nerve (P = 0.03; Wrist-axilla cross-sectional ratio). CONCLUSION In this small study, two subtypes of GBS showed different patterns of involvement that might reflect different pathomechanisms.

Sonographic evaluation of cervical nerve roots in ALS and its clinical subtypes

Morphological assessment of peripheral nerves in amyotrophic lateral sclerosis (ALS) has been available by sonography. Detection of possible axonal atrophy could be important in predicting progression. Research on correlation between sonographic findings and clinical presentation has been sparse. The aim of the study was to assess possible motor axon loss in patients with ALS by sonography and to correlate the imaging features with clinical subtypes. Patients with either definite or probable ALS and control subjects had sonographic evaluation of the cervical nerve roots (C5, C6, and C7). Each diameter and their sums were measured. The ALS patients were classified by their clinical onset and progression (arm-onset, leg-onset, bulbar, and flail-arm variant) and the sonographic features were compared. Overall, the cervical nerve roots were thinner in ALS than in the controls, but the diagnostic sensitivity was low. The patients with arm dysfunctions tended to show thinner nerve roots than those with normal or relatively preserved arm functions. The four ALS subtypes showed similar diameters of the nerve roots. There was no correlation between the disease duration and the diameters of the nerve roots. Sonography of the cervical nerve roots showed axonal atrophy in ALS and potentially reflects subtle arm dysfunctions.

Frequent hepatic steatosis in amyotrophic lateral sclerosis: Implication for systemic involvement

Abnormal energy metabolism has been reported in amyotrophic lateral sclerosis (ALS) that broadens the concept of ALS as a systemic disease. Dyslipidemia is likely to reflect the clinical outcome in ALS.

Focal nerve enlargement is not the cause for increased distal motor latency in ALS: Sonographic evaluation.

OBJECTIVE To elucidate the mechanism of focal conduction slowing in the median nerve in ALS. METHODS The patients with ALS and CTS and normal control subjects were tested with sonography of the median and ulnar nerves. The cross-sectional areas (CSAs) and the wrist-forearm CSA ratios were compared with the parameters of nerve conduction study. RESULTS The median motor distal latency was frequently prolonged in ALS and CTS. CSA and the wrist-forearm ratio of the median nerve were smaller in ALS than in CTS. The ulnar nerve sonography was similar in all the groups. CONCLUSIONS Selective conduction slowing of the median nerve at the wrist in ALS is unlikely due to secondary compressive neuropathy, as seen in carpal tunnel syndrome. SIGNIFICANCE Unique vulnerability of the median nerve in ALS may explain the selective conduction slowing.