Ultrasound accuracy for brachial plexus pathology

Objective To determine (a) the accuracy of ultrasound in detecting brachial plexus pathology and (b) outline advantages and limitations of ultrasound compared to MRI for imaging the brachial plexus. Methods 143 cases with clinically suspected brachial plexus pathology were evaluated first by ultrasound, followed by MRI. Patients with prior brachial plexus imaging were excluded. Final diagnosis was based on a combination of ultrasound, MRI, clinical follow-up, and surgical findings. Accuracy of ultrasound was assessed by comparing the ultrasound and final diagnoses. Mean clinical follow-up time following ultrasound was 1.8 ± 1.4years. Results Ninety-two (64%) of 143 cases had normal brachial plexus ultrasound and MRI examinations. Fifty-one (36%) of 143 cases had brachial plexus pathology on MRI, comprising post-radiation fibrosis (n=25,49%), nerve sheath tumor (n=11,21%), traumatic injury (n=7,14%), inflammatory polyneuropathy (n=4,8%), malignant infiltration (n=2,4%), desmoid fibromatosis (n=1,2%), and neuralgic amyotrophy (n=1,2%). Overall diagnostic accuracy of ultrasound for brachial plexus pathology was 98% (140/143), with three discordant cases (neuralgic amyotrophy n=1, inflammatory neuropathy n=1, post-radiation fibrosis n=1) regarded as normal on ultrasound assessment. Sensitivity, specificity, positive and negative predictive value of ultrasound for identifying brachial plexus pathology were 94%, 100%, 100%, and 97% respectively. Conclusion Ultrasound identifies brachial plexus pathology with high accuracy and specificity, showing comparable diagnostic efficacy to MRI. Ultrasound can serve as an effective first-line imaging investigation for suspected brachial plexus pathology.