Evaluation Of freehand high-resolution 3-dimensional ultrasound of the median nerve

The role of imaging in focal neuropathies

Electrodiagnostic testing (EDX) has been the diagnostic tool of choice in peripheral nerve disease for many years, but in recent years, peripheral nerve imaging has been used ever more frequently in daily clinical practice. Nerve ultrasound and magnetic resonance (MR) neurography are able to visualize nerve structures reliably. These techniques can aid in localizing nerve pathology and can reveal significant anatomical abnormalities underlying nerve pathology that may have been otherwise undetected by EDX. As such, nerve ultrasound and MR neurography can significantly improve diagnostic accuracy and can have a significant effect on treatment strategy. In this chapter, the basic principles and recent developments of these techniques will be discussed, as well as their potential application in several types of peripheral nerve disease, such as carpal tunnel syndrome (CTS), ulnar neuropathy at the elbow (UNE), radial neuropathy, brachial and lumbosacral plexopathy, neuralgic amyotrophy (NA), fibular, tibial, sciatic, femoral neuropathy, meralgia paresthetica, peripheral nerve trauma, tumors, and inflammatory neuropathies.

A pilot prospective cohort study using experimental quantification of early peripheral nerve regeneration with high-frequency three-dimensional tomographic ultrasound (HFtUS)

Quantification of peripheral nerve regeneration after injury relies upon subjective outcome measures or electrophysiology assessments requiring fully regenerated neurons. Nerve surgeons and researchers lack objective, quantifiable information on the site of surgical repair and regenerative front. To address this need, we developed a quantifiable, visual, clinically available measure of early peripheral nerve regeneration using high-frequency, three-dimensional, tomographic ultrasound (HFtUS). We conducted a prospective, longitudinal study of adult patients with ulnar and/or median nerve injury of the arm undergoing direct epineurial repair within 5 days of injury. Assessment of morphology, volumetric and 3D grey-scale quantification of cross-sectional views were made at baseline up to 15 months post-surgery. Sensory and motor clinical outcome measures and patient reported outcome measures (PROMs) were recorded. Five participants were recruited to the study. Our data demonstrated grey-scale values (an indication of axonal density) increased in distal stumps within 2-4 months after repair, returning to normal as regeneration completed (4-6 months) with concomitant reduction in intraneural volume as surgical oedema resolved. Two patients with abnormal regeneration were characterized by increased intraneural volume and minimal grey-scale change. HFtUS may quantify early peripheral nerve regeneration offering a window of opportunity for surgical intervention where early abnormal regeneration is detected.

Enlarged cross-sectional area of the left vagus nerve in patients with major depressive disorder

Purpose

Autonomic dysfunction and a chronic low-grade inflammation are supposed to play a role in the etiology of major depressive disorder (MDD). The vagus nerves (VN) form a major part of the parasympathetic nervous system and of the gut-brain axis. They are supposed to exert anti-inflammatory and epithelial barrier protective effects in the gut. A reduced vagal activity was described in patients with MDD. We aimed to examine the VN in patients with MDD with high-resolution ultrasound (HRUS) and hypothesized that the cross-sectional area (CSA) and the echogenicity of the VNs were altered in comparison to healthy controls.

Materials and methods

The echogenicity (gray scale mean) and the CSA of the cervical VNs at the level of the thyroid gland and both median nerves were examined with HRUS in 50 patients with MDD and 50 matched healthy controls.

Results

The left VN-CSA was significantly larger in the MDD group compared to the control group (1.7 ± 0.4 mm2 versus 1.5 ± 0.4 mm2; p = 0.045). The CSA of the right VN and both median nerves (MN) were similar between groups. In MDD subgroup analyses, recurrent depressive disorders were the main contributing factor for the left VN-CSA enlargement. Echogenicity was not altered in the VN and MN between groups.

Conclusion

The enlargement of the left VN-CSA in patients with MDD, and especially in these patients with recurrent depressive disorders, might turn out as a promising imaging biomarker. Longitudinal studies are warranted to examine whether the VNs-CSA change in the course of MDD.

Multimodal assessment of autonomic dysfunction in amyotrophic lateral sclerosis

BACKGROUND AND PURPOSE

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder with predominant progressive degeneration of motor neurons and motor deficits, but non-motor symptoms (NMS) such as cognitive and behavioural deficits are frequent and underestimated in current diagnostic pathways. Autonomic dysfunction has occasionally been described, although its frequency and relevance are unclear. The aim of this study was to investigate the role of the autonomic nervous system in ALS using a multimodal approach.

METHODS

Thirty-seven ALS patients and 40 healthy sex- and age-matched controls were included. NMS were studied with the NMS assessment scale for Parkinson's disease and an autonomic subscale was calculated. Cardioautonomic innervation at rest and whilst standing was assessed by different parameters of heart rate variability. Morphological changes (cross-sectional area) of the vagus and median nerves for control were measured with high-resolution ultrasound.

RESULTS

Non-motor symptoms in general were more frequent in ALS patients and correlated inversely with the ALS Functional Rating Scale whereas the autonomic subscore of the NMS assessment scale for Parkinson's disease did not differ between the two groups and was not related to functional impairment. Cardioautonomic assessment solely revealed an increased heart rate at rest in ALS patients, whereas the other heart rate variability parameters did not differ from controls. Structural sonographic investigation of the vagus and median nerves was similar in both groups.

CONCLUSIONS

Using a multimodal approach evidence was found for a rather mild cardio-sympathetic overactivity in ALS patients. Overall, autonomic dysfunction seems to be subtle and is not related to the functional state of ALS patients.

Axonal Degeneration of the Vagus Nerve in Parkinson's Disease-A High-Resolution Ultrasound Study

Background: Recent histopathological studies revealed degeneration of the dorsal motor nucleus early in the course of Parkinson's disease (PD). Degeneration of the vagus nerve (VN) axons following neurodegeneration of brainstem vagal nuclei should be detectable by high-resolution ultrasound (HRUS) as a thinning of the VNs.

Methods: We measured both VNs cross-sectional area (VN-CSA) of 35 patients with PD and 35 age- and sex-matched healthy controls at the level of the thyroid gland using HRUS.

Results: On both sides, the VN-CSA was significantly smaller in PD patients than in controls (right: 2.1 ± 0.4 vs. 2.3 ± 0.5 mm2, left 1.5 ± 0.4 vs. 1.8 ± 0.4 mm2; both p < 0.05). There was no correlation between the right or left VN-CSA and age, the Hoehn & Yahr stage, disease duration, the motor part of the Unified Parkinson's Disease Rating Scale score, the Montreal Cognitive Assessment score, or the Non-motor Symptoms Questionnaire, and Scale for Parkinson's disease score including its gastrointestinal domain.

Conclusions: These findings provide evidencethat atrophy of the VNs in PD patients can be detected in-vivo by HRUS.