[Current aspects in ultrasonography of the salivary glands]

[Perfusion analysis in parotid gland tumors using contrast-enhanced ultrasound (CEUS)]

OBJECTIVE

The diagnosis of parotid gland tumors is challenging due to their rarity and heterogenity. Neither conventional ultrasound nor magnetic resonance imaging (MRI) nor computed tomography (CT) allow a reliable pretherapeutic diagnosis. In addition to conventional ultrasound, contrast-enhanced ultrasound (CEUS) enables a more detailed assessment of perfusion in parotid gland tumors, thereby improving evaluation of this tumor entity. Extensive studies with analysis of perfusion characteristics in different regions of interest (ROI) in parotid gland tumors are currently lacking. This study analysed and compared perfusion parameters in different intratumoral areas of malignant and benign parotid gland tumors using CEUS.

MATERIALS AND METHODS

A total of 100 patients with tumors in the parotid gland were examined using B‑mode sonography, colour Doppler sonography and CEUS. The parameters magnitude, echogenicity, demarcation, vascularisation and in particular perfusion characteristics were measured and analysed. Analysis of quantitative CEUS parameters was performed using a specific method for perfusion analysis with certain ROI, which were allocated in a standardized manner in the entire parotid gland tumors. The perfusion parameters were compared between intratumoral ROI in the tumors and between particular tumor entities. Qualitative CEUS analysis with an estimation of perfusion patterns was additionally performed.

RESULTS

Histologically benign tumors were found in 92 cases, and malignant tumors in eight cases. CEUS analysis of perfusion patterns revealed a centripetal perfusion pattern in malignant tumors significantly more frequently than in benign tumors. In the perfusion analysis of quantitative CEUS parameters, all tumors showed higher perfusion intensities in the peripheral ROI. In benign tumors, more differences in perfusion intensity between the intratumoral ROIs were detected compared to malignant tumors.

CONCLUSION

The perfusion parameters (centripetal perfusion pattern; area under the curve) evaluated in this study have the potential to improve pretherapeutic diagnostics of parotid gland tumors in terms of differentiation of tumor entity. Further studies with larger patient cohorts are required for subsequent investigation and validation of the diagnostic accuracy of particular parameters to detect perfusion patterns potentially specific to particular tumor entities.

Salivary Gland Disorders in Children and Adolescents: A 15-year Experience

Introduction  Diseases of the salivary glands are rare in children and adolescents, with the exception of viral-induced infections.

Objective  To determine the clinical course of the disease, the diagnostic procedures, the treatment and the outcome of all children and adolescents affected with salivary gland diseases at our clinic over a period of 15 years.

Methods  A retrospective chart review including a long-term follow-up was conducted among 146 children and adolescents treated for salivary gland disorders from 2002 to 2016.

Results  Diagnosing acute sialadenitis was easily managed by all doctors regardless of their specialty. The diagnosis of sialolithiasis was rapidly made only by otorhinolaryngologists, whereas diagnosing juvenile recurrent parotitis imposed difficulties to doctors of all specialties – resulting in a significant delay between the first occurrence of symptoms and the correct diagnosis. The severity-adjusted treatment yielded improvements in all cases, and a full recovery of 75% of the cases of sialolithiasis, 73% of the cases of juvenile recurrent parotitis, and 100% of the cases of acute sialadenitis.

Conclusions  Due to their low prevalence and the lack of pathognomonic symptoms, salivary gland diseases in children and adolescents are often misdiagnosed, resulting in an unnecessarily long period of suffering despite a favorable outcome following the correct treatment.

Standards for the assessment of salivary glands - an update

The paper is an update of 2011 Standards for Ultrasound Assessment of Salivary Glands, which were developed by the Polish Ultrasound Society. We have described current ultrasound technical requirements, assessment and measurement techniques as well as guidelines for ultrasound description. We have also discussed an ultrasound image of normal salivary glands as well as the most important pathologies, such as inflammation, sialosis, collagenosis, injuries and proliferative processes, with particular emphasis on lesions indicating high risk of malignancy. In acute bacterial inflammation, the salivary glands appear as hypoechoic, enlarged or normal-sized, with increased parenchymal flow. The echogenicity is significantly increased in viral infections. Degenerative lesions may be seen in chronic inflammations. Hyperechoic deposits with acoustic shadowing can be visualized in lithiasis. Parenchymal fibrosis is a dominant feature of sialosis. Sjögren syndrome produces different pictures of salivary gland parenchymal lesions at different stages of the disease. Pleomorphic adenomas are usually hypoechoic, well-defined and polycyclic in most cases. Warthin tumor usually presents as a hypoechoic, oval-shaped lesion with anechoic cystic spaces. Malignancies are characterized by blurred outlines, irregular shape, usually heterogeneous echogenicity and pathological neovascularization. The accompanying metastatic lesions are another indicator of malignancy, however, final diagnosis should be based on biopsy findings.