[Sonography of the salivary glands]

Clinical audit of ultrasonography for detecting sialoliths in the submandibular gland in paediatric patients: A comparison to computed tomography and magnetic resonance imaging

Objectives

To compare the performance of ultrasonography with magnetic resonance imaging (MRI) and computed tomography (CT) for detecting submandibular sialoliths.

Methods

Thirteen patients with suspected submandibular sialoliths who underwent ultrasonography and CT or MRI were included. Sialoliths were diagnosed using CT (11 cases) or MRI (two cases). The submandibular duct was classified into distal and proximal ducts based on the point around the mylohyoid muscle. Sialoliths located in the proximal duct were difficult to differentiate from those located within the submandibular gland (SMG). Therefore, the location of the sialoliths was classified as follows: within the SMG/proximal duct and within the distal duct. The ultrasound results were compared with CT/MRI results.

Results

Of the 13 patients included, two had sialoliths in both the SMG/proximal duct and the distal duct, three had sialoliths in the SMG/proximal duct, and five had sialoliths in the distal duct on CT or MRI. In this small cohort, all five sialoliths in the SMG/proximal duct were detected by ultrasoonography; however, of the seven cases with sialoliths located in the distal duct, only three could be detected by ultrasonography.

Conclusions

The incidence of sialoliths in the distal duct was higher than that in the SMG/proximal duct. Ultrasonography showed a good performance compared with CT/MRI in the SMG/proximal duct but not in the distal duct.

Ultrasound in Inflammatory and Obstructive Salivary Gland Diseases: Own Experiences and a Review of the Literature

Background: Ultrasound is established as a diagnostic tool in salivary glands for obstructive diseases such as sialolithiasis and tumors. Concerning inflammatory diseases and in non-sialolithiasis-caused obstruction, much fewer data are available. In recent years, technical development has allowed a better assessment of the gland parenchyma, and knowledge about intraductal pathologies has increased considerably, which has provided new insights and a new interpretation of ultrasound findings. Objectives: To provide a comprehensive review of the literature that includes our own experiences and to point out the state of the art in ultrasound in the diagnostics of inflammatory and obstructive salivary gland diseases, taking adequate techniques and recent technical developments into consideration. Data sources and study eligibility criteria: A systematic literature search was performed in Pubmed using various specific key words. Results: According to the literature results, including our own experiences, ultrasound is of value in up to >90% of cases presenting with inflammatory and/or obstructive diseases. Technical developments (e.g., elastography) and the application of modified ultrasound techniques (e.g., transoral ultrasound) have contributed to these results. Today, ultrasound is considered a first-line diagnostic tool in these diseases. However, in some inflammatory diseases, the final diagnosis can be made only after inclusion of the anamnesis, clinical symptoms, serologic blood tests, or histopathologic investigation. Conclusions: Ultrasound can be considered as a first-line diagnostic tool in obstructive and inflammatory salivary gland diseases. In obstructive diseases, it may be sufficient for diagnostics in >90% of cases. In inflammatory diseases, ultrasound is at least an excellent screening method and can be used to establish the diagnosis in cases of an early suspicion. In all diseases ultrasound can contribute to better management and can be used for monitoring during follow-up.

The value of the twinkling artefact for the diagnosis of sialolithiasis of the large salivary glands

Objective:

The imaging of stones in the salivary glands and ducts poses a challenge, even to experienced ultrasound examiners. This study investigated whether the ‘twinkling artefact’, which occurs at internal calcific foci during Doppler ultrasound examinations, is useful for detecting salivary gland stones.

Methods:

In a model test, 20 salivary stones were analysedin vitro, via Doppler ultrasound, with regard to their representability and the triggering of the twinkling artefact. In a follow-up study, 28 patients with sialolithiasis and food-related large salivary gland swellings were examined, using both power and colour Doppler modes, with regard to the twinkling artefact. All ultrasound examinations were performed by an experienced examiner and retrospectively graded by two experienced sonographers.

Results:

All stones could reliably be detected using the twinkling artefact in the model test. Twenty-seven of 28 salivary stones (96 per cent) also showed twinklingin vivo, during patient assessment. The power Doppler mode showed a significantly higher intensity level of twinkling than the colour Doppler mode (p< 0.0001).

Conclusion:

The twinkling artefact is a very reliable sign for the diagnosis of sialolithiasis. Power Doppler is superior to colour Doppler for detection of the twinkling artefact.

The differential diagnosis of parotid gland tumors with high-resolution ultrasound in otolaryngological practice

The aim of the study is to define the utility of ultrasound (US) in differentiating benign from malignant parotid tumors as well as pleomorphic adenomas (PA) from monomorphic adenoma (MA). Seventy-two consecutive parotid gland tumors were analysed with high-resolution ultrasonography (12 MHz) with color Doppler imagining. The histopathological diagnosis was confirmed after parotidectomy for each lesion. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) for the US were established. Receiver operating characteristic curves were constructed to determine the predictive values of echogenicity, heterogeneity, and vascularity on color Doppler. Area under the curve (AUC) was calculated for each parameter considered. The analysed material included 27 MA, 26 PA, 1 basal cell adenoma, 8 inflammatory conditions, and 10 malignant neoplasms. The sensitivity, specificity, and accuracy of US in differentiation of malignant from benign lesions in the parotid gland were 60, 95.2, and 90.3%, respectively. The predictive values were: PPV 66.8% and NPV 93.6%. Differentiating diagnoses between PA and MA with US resulted in a sensitivity of 61.5%, specificity of 81.5%, and accuracy of 73.1%. The predictive values were: PPV 50% and NPV 68.8%, respectively. For distinguishing malignant from benign tumors, the highest AUC values noted were for heterogeneity and vascularization (0.8 and 0.743, respectively). The AUC values were the highest for hypoechogenicity and vascularization in separating PA from MA (0.718 and 0.685, respectively).

Differentiation of pleomorphic adenoma and Warthin's tumor of the parotid gland: ultrasonographic features

BACKGROUND

Parotid tumor is an uncommon neoplasm. Only a few studies describing the sonographic features of pleomorphic adenomas and Warthin's tumors have been published, and most of those reports are based on a relatively small number of cases.

PURPOSE

To define the sonographic characteristics of pleomorphic adenoma and Warthin's tumor in the parotid gland.

MATERIAL AND METHODS

We retrospectively evaluated the sonographic features of 77 pleomorphic adenomas in 70 patients and 93 Warthin's tumors in 61 patients. The features included tumor size, shape, border, echogenicity, and homogeneity, the presence of a cystic area, acoustic enhancement, and the grade and distribution of vascularization.

RESULTS

Lobulated lesions were observed in 49 pleomorphic adenomas and 36 Warthin's tumors. The lobulated shape was observed more frequently in pleomorphic adenomas than in Warthin's tumors (P = 0.005). Cystic areas within lesions were detected in 16 (16/77, 20.8%) pleomorphic adenomas and 42 (42/93, 45.2%) Warthin's tumors (P = 0.001). Of the pleomorphic adenomas, 77.9% had grade 0 or grade 1 vascularity, while 73.1% of Warthin's tumors had grade 2 or grade 3 vascularity (P = 0.000). Flow was peripheral in 53.2% of pleomorphic adenomas. The frequencies of central perfusion and mixed perfusion in Warthin's tumors were equal (47.3% vs. 47.3%, respectively). The differences in the vessel distribution between these two diseases was significant (P = 0.000).

CONCLUSION

Ultrasound imaging characteristics, including multiple occurrences, shape, intrinsic cystic change, and the grade and distribution of tumor vessels, can be used to differentiate pleomorphic adenomas from Warthin's tumors.

Sonography: the leading diagnostic tool for diseases of the salivary glands

Ultrasound examination is the imaging procedure with the best predictive diagnostic capability for the salivary glands. Due to the salivary glands' relatively superficial anatomical location, clear boundary from surrounding tissue and comparatively typical echogenicity, therefore sonography is ideal for diagnosis. In addition, the technical advances in recent years, including higher resolution, color Doppler sonography, contrast-enhanced ultrasound, elastography, and tissue harmonic have lead to an improvement in diagnostic accuracy of sonography further resulting in an expansion of the range of indications. Sonography allows detection of obstructive salivary gland diseases such as stenosis or sialolithiasis, as well as sialadenosis such as Sjögren syndrome. Ultrasound examination alone is sufficient to diagnose benign tumors. However, in the case of malignant tumors, computer tomography or MRI may be also required, especially to determine the question of infiltration of the skull base.

Clinical ultrasound of the salivary glands

Ultrasound investigation of the major salivary glands has been routinely used for the past 25 years. Ultrasound provides an immediate diagnosis in acute or chronic inflammatory salivary diseases and can visualize sialolithiasis as small as 0.4 mm. Ultrasound is also an important imaging modality for salivary gland tumors, guiding fine needle aspiration (FNA) for cytological diagnosis. It is particularly sensitive in detecting suspicious lymph nodes in the neck and helps to guide FNA. Ultrasound is a first-line tool for diagnosis of salivary pathology. It is simple to use, noninvasive, and well tolerated, even in children.

Potential of ultrasound diagnosis for parotid tumors: analysis of qualitative and quantitative parameters

OBJECTIVE

Histology of parotid tumors determines the extent of surgery. The aim was to test ultrasound (US) contrast enhancer-kinetics to identify histologic entities, possibly being superior to qualitative morphological parameters.

STUDY DESIGN

In a cross-sectional assessment of ultrasound diagnosis, the subjective US-classification was compared with contrast analysis with histology as gold standard.

SUBJECTS AND METHODS

A total of 64 male and 61 female patients with a mean age of 54 years were included, with 13 malignant tumors. These were classified with US morphology, then time-dependent contrast medium analysis.

RESULTS

A total of 92.8% of tumors were classified correctly as malignant or benign. The sensitivity, specificity, positive- and negative-predictive values were 66.7%, 86.3%, 60.6%, and 89.1% for differentiating Warthin tumors, but only 46.2%, 98.2%, 75%, and 94% for malignant lesions. Contrast parameters yielded significant parameters for benign tumors, not for malignant entities.

CONCLUSION

Although contrast medium analysis provided statistical criteria, these, however, do not possess the ability to improve the diagnostic prediction of tumor histology. Neither the morphologic classification nor contrast medium analysis was able to identify a malignant lesion sufficiently.

Neither MRI, CT nor US is superior to diagnose tumors in the salivary glands--an extended case study

OBJECTIVES

Ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI) are the most common radiological procedures for the diagnosis of tumor-like lesions of the salivary glands. The aim of the present study was to determine whether MRI or CT provide additional information besides that delivered by US.

STUDY DESIGN/METHODS

109 patients with a tumor-like lesion of the salivary glands underwent surgery. MRI and CT were arranged in 73 and in 40 patients respectively, whereas all 109 patients were prospectively diagnosed by US. The results of CT, MRI and US were compared with the histological outcome. Furthermore, the recent rise in the number of CT and MRI studies was investigated.

RESULTS

On CT and MRI, there was no rise in the percentage of malignant tumors or advanced surgical procedures. In respect of the radiological assessment of the lesion (benign/malignant) and the correct diagnosis, CT, MRI and US were comparable in terms of sensitivity, specificity and accuracy. No significant difference was found in the Chi-square test (p > 0.05).

CONCLUSION

The evaluation of the preoperative results of CT, MRI and US revealed no advantage for CT or MRI; these procedures are only required in specific cases. An update or revision of the current preoperative diagnostic management is deemed necessary.

Intraoral sonographic evaluation of parapharyngeal space tumors

We performed transcutaneous (external) sonography and then intraoral sonography to evaluate 3 parapharyngeal space tumors (1 vagal paraganglioma, 1 pleomorphic adenoma, and 1 carcinoma arising in a pleomorphic adenoma). All 3 patients had medial displacement of a tonsil. In all cases, we could measure the size and see the borders of the tumors and their relation to other structures on intraoral sonography. Intraoral sonography is useful for differentiating between unilaterally enlarged and medially displaced tonsils.

A comparative study of sonographic and histopathologic findings of tumorous lesions in the parotid gland

OBJECTIVE

The purpose of this study was to clarify which histopathologic features are visualized on sonograms by comparing sonomorphologic and histopathologic analyses of parotid tumorous lesions on the same plane.

STUDY DESIGN

Boundaries, shapes, echo intensity level, distribution of internal echoes, and acoustic enhancement on sonograms of 86 parotid tumorous lesions were retrospectively compared with the histopathologic findings.

RESULTS

Unclear boundaries on sonograms corresponded to abundant connective tissue with scattered tumor cell nests. Polygonal shapes on sonograms were revealed to represent tumor cell infiltration on histopathologic sections. The "very hypoechoic" lesions showed significantly high ratio of cystic areas (P < .05) in Warthin tumor. The weakly hyperechoic structures on sonograms were connective tissue, hyaline, and necrotic and keratinized materials. Attenuated posterior echoes were observed in malignant tumors with abundant connective tissue and metaplastic bone formation.

CONCLUSIONS

To facilitate correct sonographic diagnosis, it is important to ascertain the correlation between sonomorphology and histopathology.

Statistical study for sonographic differential diagnosis of tumorous lesions in the parotid gland

OBJECTIVE

The purpose of this study was to clarify characteristic sonomorphologic features of parotid lesions statistically and to propose new criteria for the differential diagnosis.

STUDY DESIGN

Eighty-six tumorous lesions were analyzed with regard to the following sonomorphologic features: boundary, shape, echo intensity level, distribution of internal echoes, and acoustic enhancement. Stepwise polychotomous logistic regression analysis was performed to assess characteristic sonographic features. As dependent variables, we used "pleomorphic adenoma," "Warthin tumor," "malignant tumors" and "other benign lesions"; as predictor variables, we used the aforementioned sonomorphologic features. Proportion of the occurrence of each dependent variable was calculated.

RESULTS

Lobular shape and homogeneous internal echoes predicted pleomorphic adenoma. A lesion with multiple anechoic areas would be Warthin tumor with very high sensitivity. Malignant tumors showed either heterogeneous internal echoes without characteristic structures or polygonal shape.

CONCLUSIONS

These sonomorphologic features should be observed to make more exact differential diagnoses for operation and therapy planning.

Ultrasonographic biometry in salivary glands

Specifications about the size of healthy salivary glands are not available to date. Therefore, we determined the size of the submandibular and the parotid glands by ultrasonography in 50 subjects (25 men, 25 women, mean age 45 y, range 20-68) with no history of disease affecting the salivary glands. The subjects were equally distributed concerning gender and age. Body weight did not differ more than 20% from the ideal weight following Broca's formula (mean body weight 71 kg, range 46-95 kg). In the submandibular glands we found an anterior-posterior length of 35 mm +/- 5.7 mm, a paramandibular dimension to the depth of 14.3 mm +/- 2.9 mm and a dimension in frontal scanning of 33.7 mm +/- 5.4 mm. The parotid glands were measured 46.3 mm +/- 7.7 mm in the axis parallel to the mandibular ramus and 37.4 mm +/- 5.6 mm in the transversel axis. The dimension of the parotid parenchyma was measured with 7.4 mm +/- 1.7 mm lateral to the mandible and 22.8 mm +/- 3.6 mm dorsal to the mandible. No statistically significant difference to the 5%-level was found concerning gender. The dimension of the parotid glands correlated statistically significantly with body weight (p = 0.03). This correlation was not found in the dimension of the submandibular glands. Age did not correlate with the dimension of salivary glands. Results of the submandibular glands were compared with volume measurements of submandibular glands from cadavers.

Ultrasonographic biometry in normal salivary glands

Specifications about the sizes of normal salivary glands are not available. We used ultrasonography to determine the sizes of the submandibular and parotid glands in 50 subjects, who were not suffering from diseases of the salivary glands. Volunteers were distributed equally concerning sex and age. Body weight did not differ more than 20% from ideal weight. Dimensions of the submandibular glands were: anterior-posterior length, 35 +/- 5.7 mm; paramandibular extension to gland depth, 14.3 +/- 5.7 mm; extension in frontal scanning, 33.7 +/- 5.4 mm. The parotid glands measured 46.3 +/- 7.7 mm in the axis parallel to the mandibular ramus and 37.4 +/- 5.6 mm in a transverse axis. The extensions of the parotid parenchyma were 7.4 +/- 1.7 mm lateral to the mandible and 22.8 +/- 3.6 mm dorsal to the mandible.