Diagnosis of cervical plexus tumours by high-frequency ultrasonography

Abstract

Background: Cervical plexus (CP) tumours are difficult to diagnose because of atypical symptoms. This study aimed to summarize the features of a normal CP and CP tumours observed on high-frequency ultrasonography.

Methods: The ultrasound data of 11 CP tumour patients and 22 normal volunteers were collected. All 11 patients underwent magnetic resonance imaging (MRI), and 4 patients also underwent computed tomography (CT). The imaging data were compared with surgery and pathology data.

Results: The C7 vertebra and bifurcation of the carotid common artery (CCA) were useful anatomic markers for identifying the CP. In contrast to the C1 nerve (22.7%), the C2-4 nerves were well displayed and thinner than the brachial plexus (P < 0.05). CP tumours were more common in females (72.7%) and generally located at C4 (72.7%) on the right side (81.8%). Additionally, the nerve trunk in tumour patients was obviously wider than that in normal controls (7.49 ± 1.03 mm vs 2.67 ± 0.36 mm, P < 0.01). Compared with pathology, the diagnostic rates of CP tumours by MRI, CT and high-frequency ultrasound were 72.7% (8/11), 25% (1/4) and 90.9% (10/11), respectively.

Conclusions: The diagnosis of CP neuropathy is accurate and reliable by high-frequency ultrasound, and the C7 vertebra and bifurcation of the CCA are useful anatomic markers in CP ultrasonography.

Keywords: Cervical plexus; High-frequency ultrasonography; Tumour.

Fig. 1

Normal cervical plexus and its anatomical markers. A Anatomic diagram of the CP. B Longitudinal view of the C3–C5 roots (arrows), which appear as tubular hypoechoic structures with echogenic walls and a fibrillar texture. C The C7 vertebra was used as an anatomical marker to identify the CP. Arrows point to cervical nerve C7 (transverse view, arrow) and the PT. D The bifurcation of the common carotid artery served as another anatomical marker for identifying the CP (C4 level); the arrow indicates C4. PT posterior tubercle, AT anterior tubercle, VA vertebral artery, ECA external carotid artery, ICA internal carotid artery

Fig. 2

MRI, CT and contrast ultrasound images of cervical plexus schwannomas (C3 level). A 2D ultrasonography of the transverse process of the vertebra, where M is the neuroma lesion originating from the intervertebral foramen. B Colour Doppler ultrasonography showing the blood flow signal in the mass. C Contrast-enhanced ultrasound showing rich blood perfusion. D, E MRI sagittal and cross-sections of a CP mass: the arrow indicates the lesion growing outwards from the intervertebral foramen. F The arrow indicates the enlarged intervertebral foramen (3D CT reconstruction)

Fig. 3

Intraoperative view and pathology of schwannoma. A Intraoperative image shows the schwannoma in the C4 CP. The blue arrow indicates the neural lesion. B HE (× 400) staining confirmed schwannoma. C, D NF and S-100 (× 400) staining demonstrating nuclear and cytoplasmic immunoreactivity