Ultrasound and EMG-NCV study (electromyography and nerve conduction velocity) correlation in diagnosis of nerve pathologies.

Abstract

Nerve disorders are commonly encountered in clinical practice. Ultrasonography (USG) is a useful modality in the evaluation of most of the peripheral and superficial pathologies amenable to penetration by ultrasound. The primary objective is to study the USG findings of various peripheral nerve pathologies and to correlate them with electrophysiological (EMG-NCV) findings. 42 patients referred with suspicion of peripheral nervous system affection were evaluated with USG along with EMG-NCV. After reviewing detailed anatomy of the region, the affected nerve was visualized along the major neurovascular bundle or at a known anatomical landmark with a high-frequency (9-20MHz) linear/hockey stick transducer. The USG parameters, namely loss of fibrillary pattern, hypoechogenicity and nerve thickening, showed significant p value (p<0.05) on the tests of significance, suggesting these parameters are significant predictors of nerve affection/pathology on USG. Each ultrasound parameter was correlated individually with SNAP and CMAP. The results revealed positive correlation of echogenicity (r=0.210, p=0.05), fibrillary pattern (r=0.209, p=0.05) and thickening (r=0.387, p<0.05) with sensory nerve action potential (SNAP) and compound muscle action potential (CMAP). USG can be used as corroborative investigation to strengthen the findings of EMG-NCV. This combination represents a powerful tool in enabling appropriate planning for treatment, preventing unnecessary intervention and thus improving overall outcomes in patients with peripheral neuropathy.