Possibilities of ultrasound diagnostics of paragangliomas of the neck

Abstract

The purpose of the study is to evaluate the results of ultrasound examination, generalize the criteria for differential diagnosis of various types of paragangliomas in neck area and the development of a standard ultrasound protocol that provides information about the resectability of formations.Material and methods. 91 patients (100 tumors) with a clinical diagnosis of neurogenic neck tumor were examined, of which 71 (71%) were carotid paragangliomas, 18 (18%) – vagal paragangliomas, 10 (10%) – neurinomas and 1 (1%) – neurofibroma. All patients underwent ultrasound examination, including examination of the tumor structure in B-mode, assessment of the size and prevalence formations relative to the base of the skull and color Doppler mapping to assess the degree of intra-tumor blood flow and the relationship of formations with carotid arteries.The study allowed us to systematize the main ultrasound signs characteristic of various neurogenic neck tumors, among which we identified: clear, even contours; the presence of a capsule; a heterogeneous, predominantly hypoechoic structure with hyperechoic inclusions resembling “salt–pepper”. The following parameters played a crucial role in differential diagnosis: localization of formation, features of intra-tumor blood flow and the relationship of paragangliomas with carotid arteries.Results. Evaluation of the structural features of the tumor in the B-mode did not show significant differences between various paragangliomas, neurinomas and neurofibromas, all formations had clear, even contours, their capsule was clearly visualized. For carotid paragangliomas in all 71 (100%) observations, the characteristic feature was the location in the bifurcation area of the common carotid artery, with the mouths of the internal and external carotid arteries moving apart, which was 100% the diagnostic criterion of this group of formations. Vagal paragangliomas or neurinomas in all cases were located outside the bifurcation of the carotid artery, although in close proximity to the carotid arteries. The nature and degree of intra–tumor vasularization is another argument in the differential diagnosis of paragangliomas, which, unlike other neurogenic tumors, are highly vascularized tumors. The study of the nature of the intracellular blood flow showed that arterial paragangliomas predominate vessels, unlike neurinomas and neurofibromas, have significantly poorer vascularization with a predominance of venous vessels in the structure of the tumor. In 8 (44%) cases, vagal paragangliomas sprouted into the adventitia of the carotid arteries, which was characterized by a local increase in blood flow in this area in combination with turbulence during ultrasound.Conclusion. The proposed algorithm of ultrasound examination of neurogenic formations in the neck area makes it possible already at the primary stage instrumental diagnostics to identify volumetric formations, differentiate them between themselves and with other neck formations and to assume the degree of traumatism of the proposed surgical intervention.