Evaluation of Parotid Lesions

Machine Learning on Ultrasound Texture Analysis Data for Characterizing of Salivary Glandular Tumors: A Feasibility Study

BACKGROUND

Objective quantitative texture characteristics may be helpful in salivary glandular tumor differential diagnosis. This study uses machine learning (ML) to explore and validate the performance of ultrasound (US) texture features in diagnosing salivary glandular tumors.

MATERIAL AND METHODS

122 patients with salivary glandular tumors, including 71 benign and 51 malignant tumors, are enrolled. Representative brightness mode US pictures are selected for further Gray Level Co-occurrence Matrix (GLCM) texture analysis. We use a t-test to test the significance and use the receiver operating characteristic curve method to find the optimal cut-point for these significant features. After splitting 80% of the data into a training set and 20% data into a testing set, we use five machine learning models, k-nearest Neighbors (kNN), Naïve Bayes, Logistic regression, Artificial Neural Networks (ANNs) and supportive vector machine (SVM), to explore and validate the performance of US GLCM texture features in diagnosing salivary glandular tumors.

RESULTS

This study includes 49 female and 73 male patients, with a mean age of 53 years old, ranging from 21 to 93. We find that six GLCM texture features (contrast, inverse difference movement, entropy, dissimilarity, inverse difference and difference entropy) are significantly different between benign and malignant tumors (p < 0.05). In ML, the overall accuracy rates are 74.3% (95%CI: 59.8-88.8%), 94.3% (86.6-100%), 72% (54-89%), 84% (69.5-97.3%) and 73.5% (58.7-88.4%) for kNN, Naïve Bayes, Logistic regression, a one-node ANN and SVM, respectively.

CONCLUSIONS

US texture analysis with ML has potential as an objective and valuable tool to make a differential diagnosis between benign and malignant salivary gland tumors.

Parotid Gland Segmentation Using Purely Transformer-Based U-Shaped Network and Multimodal MRI

Parotid gland tumors account for approximately 2% to 10% of head and neck tumors. Segmentation of parotid glands and tumors on magnetic resonance images is essential in accurately diagnosing and selecting appropriate surgical plans. However, segmentation of parotid glands is particularly challenging due to their variable shape and low contrast with surrounding structures. Recently, deep learning has developed rapidly, and Transformer-based networks have performed well on many computer vision tasks. However, Transformer-based networks have yet to be well used in parotid gland segmentation tasks. We collected a multi-center multimodal parotid gland MRI dataset and implemented parotid gland segmentation using a purely Transformer-based U-shaped segmentation network. We used both absolute and relative positional encoding to improve parotid gland segmentation and achieved multimodal information fusion without increasing the network computation. In addition, our novel training approach reduces the clinician's labeling workload by nearly half. Our method achieved good segmentation of both parotid glands and tumors. On the test set, our model achieved a Dice-Similarity Coefficient of 86.99%, Pixel Accuracy of 99.19%, Mean Intersection over Union of 81.79%, and Hausdorff Distance of 3.87. The purely Transformer-based U-shaped segmentation network we used outperforms other convolutional neural networks. In addition, our method can effectively fuse the information from multi-center multimodal MRI dataset, thus improving the parotid gland segmentation.

Basal cell adenoma and basal cell adenocarcinoma of the parotid gland: clinical findings and surgical outcomes in a single-institution study

BACKGROUND

Basal cell adenoma (BCA) is a rare benign tumor within the salivary glands. Basal cell adenocarcinoma (BCAC), the malignant counterpart of BCA, is also an exceedingly rare tumor with very limited clinical studies conducted. This study aims to investigate the clinical characteristics, demographics, and surgical outcomes of patients diagnosed with BCA and BCAC within the parotid gland.

METHODS

A retrospective analysis from May 2003 to August 2023 was performed for all patients undergoing parotidectomy for masses. Retrospective data on gender, age, tumor characteristics, and outcomes were collected. Surgical approaches, including negative margin attainment, capsule removal, and histological diagnosis, were also detailed.

RESULTS

The study included 1268 patients who underwent parotidectomy, resulting in 81 cases of BCA and 7 cases of BCAC. BCA patients, with a mean age of 55.1 years, showed diverse age distribution and predominantly presented in the 50s. In BCAC cases, seven female patients exhibited a predominant location in the deep lobes. FNA revealed BCAC in three out of seven cases, and subsequent parotidectomy was performed, resulting in no observed recurrences or metastases.

CONCLUSION

This study reports the largest number of BCA cases from a single institution and provides comprehensive insights into the demographics, tumor characteristics, and clinical outcomes of both BCA and BCAC. Although further research should be conducted, based on clinical follow-up results, appropriately including the capsule in the tumor excision indicates favorable outcomes, especially when the tumor size is not large.

Cytopathological analysis of salivary gland cancer: REFCOR recommendations by the formal consensus method

OBJECTIVE

To determine the indications for fine-needle cytology and the modalities of frozen section pathological analysis in the management of salivary gland cancer.

MATERIAL AND METHODS

The French Network of Rare Head and Neck Tumors (REFCOR) formed a steering group who drafted a narrative review of the literature published on Medline and proposed recommendations. The level of adherence to the recommendations was then assessed by a rating group according to the formal consensus method.

RESULTS

Fine-needle cytology is recommended as part of the diagnostic work-up for a major salivary gland tumor suspicious for malignancy. Fine-needle cytology should be performed after MRI to avoid artifacts. Frozen section analysis is recommended to confirm the malignant nature of the tumor, to adapt the extent of resection and to indicate neck dissection. Whenever possible, the entire tumor and adjacent salivary or periglandular tissue should be sent for frozen section analysis.

CONCLUSION

Fine-needle cytology and frozen section analysis play an essential role in the management of salivary gland cancers.

Neural network combining with clinical ultrasonography: A new approach for classification of salivary gland tumors

OBJECTIVE

Little information is available about deep learning methods used in ultrasound images of salivary gland tumors. We aimed to compare the accuracy of the ultrasound-trained model to computed tomography or magnetic resonance imaging trained model.

MATERIALS AND METHODS

Six hundred and thirty-eight patients were included in this retrospective study. There were 558 benign and 80 malignant salivary gland tumors. A total of 500 images (250 benign and 250 malignant) were acquired in the training and validation set, then 62 images (31 benign and 31 malignant) in the test set. Both machine learning and deep learning were used in our model.

RESULTS

The test accuracy, sensitivity, and specificity of our final model were 93.5%, 100%, and 87%, respectively. There were no over fitting in our model as the validation accuracy was similar with the test accuracy.

CONCLUSIONS

The sensitivity and specificity were comparable with current MRI and CT images using artificial intelligence.

Diagnosis and Management of Parotid Gland Cancer with Focus on the Role of Preoperative Fine-Needle Aspiration Cytology: A 10-Year-Long Retrospective Study with 5-Year Follow-Up

Introduction

Salivary gland cancers represent a rare heterogeneous group of neoplasms with complex clinicopathological characteristics and distinct biological behaviour. The appropriate diagnosis and management of parotid gland cancer are challenging and should be based on the clinical, imaging, cytological, and histological features. The present study analysed the use of preoperative fine-needle aspiration cytology (FNAC) and intraoperative frozen section (FS) to guide the appropriate surgical and postoperative treatment of parotid gland cancers.

Materials and Methods

We selected 48 patients with primary malignancy of the parotid gland surgically treated between 1 January 2008 and 30 June 2017 at the Maxillo-Facial Surgery Division, University Hospital of Parma, Italy. The patients had postoperative histological diagnosis of malignant parotid cancer and were followed up for longer than 5 years.

Results

The 48 patients included in this study had a mean age of 56.7 years. The most frequent type of parotid gland cancer was carcinoma ex pleomorphic adenoma (22.9%), followed by mucoepidermoid carcinoma (16.7%) and acinic cell carcinoma (14.6%). All 48 patients underwent preoperative FNAC: 29 (60.4%) and 19 (39.6%) were suggestive of malignant and benign lesions, respectively. In 31 patients, intraoperative FS was performed.

Discussion

Compared to previous studies, the present study showed significantly lower diagnostic sensitivity of FNAC for parotid gland cancers. The preoperative diagnostic accuracy for suspected malignant cases may be improved by repeat analysis of the cytological specimen by experts, preoperative core needle biopsy, and/or intraoperative FS analysis of the suspected mass.

The Diagnostic Value of Fine Needle Aspiration Biopsy in Parotid Tumors

The aim of this study was to investigate the diagnostic accuracy rates of the patients who underwent an operation for parotid mass, by comparing their fine needle aspiration biopsy (FNAB) cytology results with the final pathology. A total of 136 patient files of those who applied to Otorhinolaryngology clinic due to parotid mass and underwent parotidectomy procedure between 2010 and 2020 at a tertiary center were scanned retrospectively. Database on patient age, gender, preoperative FNAB results, and final surgical histopathology results was created. The mean age of the patients was 48.26 ± 17.37 Superficial parotidectomy was performed to 108 (79.4%) and total parotidectomy to 28 (20.6%) of the patients. The sensitivity of FNAB was found as 85.2%, specificity as 96.2%, positive predictive value as 85.2%, negative predictive value as 96.2% and accuracy as 94.0%. It is found that FNAB has the high specificity and high negative predictive value with high diagnostic accuracy on detecting preoperative malignancy in parotid gland. We think that FNAB is a significant, necessary and safe method in the diagnosis of parotid lesions in preoperative sense.

Ultrasonographic prediction model for benign and malignant salivary gland tumors: a preliminary study

OBJECTIVE

To establish an ultrasonographic (US) prediction model for benign and malignant salivary gland tumors.

STUDY DESIGN

We retrospectively analyzed the clinical data of 575 patients with salivary gland tumors. Patients were divided into benign (N = 420) and malignant (N = 155) tumor groups based on histopathologic results. The clinical and US features of the tumor groups were statistically compared. With histopathologic findings as the dependent variable and clinical and US features as independent variables, a multiple logistic regression model was established. The area under the receiver operating characteristic curve (AUC) was calculated to evaluate its diagnostic efficacy.

RESULTS

Statistically significant differences between tumor groups were discovered for patient age, tumor site, and the US features of tumor size, shape, and margins; posterior echo pattern; microcalcification, abnormal lymph nodes, and tumor vascularity. Individual US features had limited diagnostic value. The AUC, sensitivity, specificity, and accuracy values of the logistic regression equation were 0.893, 84.3%, 80.0%, and 83.1%, respectively.

CONCLUSION

The diagnostic performance of the predictive model was significantly better than that of any single US factor. This suggests that establishment of multiple models based on US features can improve the accuracy of diagnosis of benign and malignant salivary gland tumors and can be applied clinically.

Assessment of a limited-access parotidectomy technique's complications and scar characteristics - A cohort study

OBJECTIVE

Parotidectomy is the treatment of choice for benign tumors of the parotid gland, with the modified Blair incision most commonly utilized. This retrospective analysis aimed to determine the incidence of complications and assess the relationship between the mass and scar characteristics, in patients who had undergone parotidectomy.

MATERIALS AND METHODS

The scar characteristics of patients who had undergone parotidectomy for benign neoplasms at our medical center between 2013 and 2019 were evaluated.

RESULTS

Overall, 49 patients met the inclusion criteria, of whom 33 agreed to participate in the study. The mean patient age was 52.8 years; 57.5% were males. No correlation was identified between the parotid mass size or location and scar type or length. The most common complications in this study were similar to those reported in the literature.

CONCLUSION

The results of this study suggest that the smaller, tailored modified Blair incision for parotidectomy does not increase complication rates. Future studies with larger cohorts should be conducted to further assess the potential benefits of tailored incision size during modified Blair parotidectomies.

Advanced magnetic resonance imaging findings in salivary gland tumors

Salivary gland tumors (SGTs) make up a small portion (approximately 5%) of all head and neck tumors. Most of them are located in the parotid glands, while they are less frequently located in the submandibular glands, minor salivary glands or sublingual gland. The incidence of malignant or benign tumors (BTs) in the salivary glands varies according to the salivary gland from which they originate. While most of those detected in the parotid gland tend to be benign, the incidence of malignancy increases in other glands. The use of magnetic resonance imaging (MRI) in the diagnosis of SGTs is increasing every day. While conventional sequences provide sufficient data on the presence, localization, extent and number of the tumor, they are insufficient for tumor specification. With the widespread use of advanced techniques such as diffusion-weighted imaging, semi-quantitative and quantitative perfusion MRI, studies and data have been published on the differentiation of malignant or BTs and the specificity of their subtypes. With diffusion MRI, differentiation can be made by utilizing the cellularity and microstructural properties of tumors. For example, SGTs such as high cellular Warthin’s tumor (WT) or lymphoma on diffusion MRI have been reported to have significantly lower apparent diffusion values than other tumors. Contrast agent uptake and wash-out levels of tumors can be detected with semi-quantitative perfusion MRI. For example, it is reported that almost all of the pleomorphic adenomas show an increasing enhancement time intensity curve and do not wash-out. On quantitative perfusion MRI studies using perfusion parameters such as Ktrans, Kep, and Ve, it is reported that WTs can show higher Kep and lower Ve values than other tumors. In this study, the contribution of advanced MRI to the diagnosis and differential diagnosis of SGTs will be reviewed.

Radiomics and deep learning approach to the differential diagnosis of parotid gland tumors

PURPOSE OF REVIEW

Advances in computer technology and growing expectations from computer-aided systems have led to the evolution of artificial intelligence into subsets, such as deep learning and radiomics, and the use of these systems is revolutionizing modern radiological diagnosis. In this review, artificial intelligence applications developed with radiomics and deep learning methods in the differential diagnosis of parotid gland tumors (PGTs) will be overviewed.

RECENT FINDINGS

The development of artificial intelligence models has opened new scenarios owing to the possibility of assessing features of medical images that usually are not evaluated by physicians. Radiomics and deep learning models come to the forefront in computer-aided diagnosis of medical images, even though their applications in the differential diagnosis of PGTs have been limited because of the scarcity of data sets related to these rare neoplasms. Nevertheless, recent studies have shown that artificial intelligence tools can classify common PGTs with reasonable accuracy.

SUMMARY

All studies aimed at the differential diagnosis of benign vs. malignant PGTs or the identification of the commonest PGT subtypes were identified, and five studies were found that focused on deep learning-based differential diagnosis of PGTs. Data sets were created in three of these studies with MRI and in two with computed tomography (CT). Additional seven studies were related to radiomics. Of these, four were on MRI-based radiomics, two on CT-based radiomics, and one compared MRI and CT-based radiomics in the same patients.

Partial parotid sialoadenectomy in a horse with parotid ductal carcinoma: Surgical description and case report

OBJECTIVES

To describe the surgical findings, histopathological features, and long-term outcome for a horse with parotid salivary carcinoma.

STUDY DESIGN

Case report ANIMALS: Twelve year old American Quarter Horse gelding.

METHODS

The gelding was presented for a 10 × 10 cm swelling below the base of the right ear. Ultrasonographic examination revealed a mass involving the right parotid salivary gland. Incisional biopsy was consistent with parotid carcinoma. The tumor was marginally excised. The lateral wall of the guttural pouch was excised with the mass and was reconstructed with a porcine small intestinal submucosal (SIS) sheet. Cisplatin beads were implanted in the wound bed prior to closure. Firocoxib (0.1 mg/kg orally, daily, every 24 h) treatment was initiated.

RESULTS

Postoperative complications included right-sided facial nerve paralysis, difficulty with deglutition of fibrous feeds, and surgical site dehiscence. Wound healing was achieved by second intention. Partial improvement in nerve function was observed within the first 6 months. At 12 months postparotidectomy, no sign of tumor reoccurrence or metastatic disease was present, and the gelding returned to work.

CONCLUSION

Partial parotid sialoadenectomy was performed with a favorable long-term outcome. Regional anatomic knowledge is crucial.

Cancer or Tuberculosis: A Comprehensive Review of the Clinical and Imaging Features in Diagnosis of the Confusing Mass

Confusing masses constitute a challenging clinical problem for differentiating between cancer and tuberculosis diagnoses. This review summarizes the major theories designed to identify factors associated with misdiagnosis, such as imaging features, laboratory tests, and clinical characteristics. Then, the clinical experiences regarding the misdiagnosis of cancer and tuberculosis are summarized. Finally, the main diagnostic points and differential diagnostic criteria are explored, and the characteristics of multimodal imaging and radiomics are summarized.

Cross-sectional imaging and cytologic investigations in the preoperative diagnosis of parotid gland tumors - An updated literature review

An accurate preoperative diagnosis of parotid tumors is essential for the selection and planning of surgical treatment. Various modern cross-sectional imaging and cytologic investigations can support the differential diagnosis of parotid tumors. The aim of this study was to achieve a comprehensive and updated review of modern imaging and cytologic investigations used in parotid tumor diagnosis, based on the latest literature data. This literature review could serve as a guide for clinicians in selecting different types of investigations for the preoperative differential diagnosis of parotid tumors. Magnetic resonance imaging (MRI) with its dynamic and advanced sequences is the first-line imaging investigation used in differentiating parotid tumors. Computed tomography (CT) and positron emission tomography (PET)-CT provide limited indications in differentiating parotid tumors. Fine needle aspiration biopsy and core needle biopsy can contribute with satisfactory results to the cytological diagnosis of parotid tumors. Dynamic MRI with its dynamic contrast-enhanced and diffusion-weighted sequences provides the best accuracy for the preoperative differential diagnosis of parotid tumors. CT allows the best evaluation of bone invasion, being useful when MRI cannot be performed, and PET-CT has value in the follow-up of cancer patients. The dual cytological and imaging approach is the safest method for an accurate differential diagnosis of parotid tumors.

Narrative review of multiparametric ultrasound in parotid gland evaluation

Disorders affecting parotid gland represent a heterogeneous group comprising congenital, inflammatory and neoplastic diseases which show a focal or diffuse pattern of appearance. The differentiation of neoplastic from non-neoplastic conditions of parotid glands is pivotal for the diagnostic imaging. Frequently there is evidence of overlapping between the clinical and the imaging appearance of the various pathologies. The parotid gland is also often object of study with the combination of different techniques [ultrasound-computed tomography-magnetic resonance imaging (US-CT-MRI), ex.]. Compared to other dominant methods of medical imaging, US has several advantages providing images in real-time at lower cost, and without harmful use of ionizing radiation and of contrast enhancement. B-mode US, and the microvascular pattern color Doppler are usually used as first step evaluation of parotid lesions. Elastography and contrast-enhanced US (CEUS) has opened further possible perspectives to improve the differentiation between benign and malignant parotid lesions. The characterization of the parotid tumors plays a crucial role for their treatment planning and for the prediction of possible surgical complications. We present, here an updated review of the most recurrent pathologies of parotid gland focusing on the diagnostic power of multiparametric US including CEUS and ultrasound elastography (USE); limitations, advantages and the main key-points will be presented.

The diagnostic performance of ultrasound-guided core biopsy in the diagnosis of head and neck lymphoma: results in 226 patients

Many clinical guidelines for investigating lymphomas advise that surgical excision biopsy (SEB) should be performed for a confident diagnosis. It is increasingly recognized in clinical practice that ultrasound-guided core needle biopsy (USCNB) is a reliable diagnostic technique. We aimed to investigate the diagnostic efficacy of USCNB in head and neck lymphoma. A retrospective analysis of all diagnosed head and neck lymphomas between 2013 and 2018 was performed. Patient records, radiology and histopathology reports along with the biopsy technique: fine needle aspiration cytology (FNAC), USCNB, and SEB used were reviewed. The technique providing diagnosis and leading to initiation of treatment was identified. Two-hundred and thirty patients and 267 biopsy samples were included. A total of 226 patients underwent USCN. In 215 of 226 (95.1%) USCNB patients were fully diagnostic allowing for initiation of oncological treatment; 11 patients required a subsequent SEB to provide diagnosis. In four patients, SEB was the only investigation performed. Of the USCNB total number of procedures (number of patients n=230 is the same coincidentally as the number of USCNB procedures), 215 of 230 (93.5%) were fully diagnostic samples. In the majority of cases, USCNB provided a definitive diagnosis allowing initiation of oncological treatment, avoiding the need for SEB. USCNB should be considered the first-line diagnostic modality in appropriate cases, as it reduces time to initiate treatment, costs and avoids patients having to undergo unnecessary surgery and possible complications.

Rheumatoid Nodule Simulating a Parotid Tumor

Rheumatoid nodules are an extra-articular manifestation of rheumatoid arthritis that are rarely found in the maxillofacial region. A 59-year-old woman with rheumatoid arthritis treated with methotrexate, leflunomide, and tocilizumab, presented with an enlarging mass in the left parotid region. Magnetic resonance imaging (MRI) displayed a lesion compatible with a neoplasm. However, an incisional biopsy showed features consistent with a rheumatoid nodule. The patient was managed conservatively, including cessation of methotrexate and initiation of treatment with hydroxychloroquine. At 15-month follow-up, the lesion had a significant reduction in size. To our knowledge, this is the first case report of a rheumatoid nodule in the parotid region. Although it is a rare manifestation, clinicians should consider this a possible differential diagnosis of parotid masses in patients with a history of rheumatoid arthritis or connective tissue disease.

A Novel Sonographic Scoring Model in the Prediction of Major Salivary Gland Tumors

OBJECTIVES

To create a sonographic scoring model in the prediction of major salivary gland tumors and to assess the utility of this predictive model.

STUDY DESIGN

Retrospective case series, academic tertiary referral center.

METHODS

Two hundred fifty-nine patients who underwent ultrasound (US), US-guided needle biopsies, and subsequent operations were enrolled. These data were used to build a predictive scoring model and the model was validated by 10-fold cross-validation.

RESULTS

We constructed a sonographic scoring model by multivariate logistic regression analysis: 2.08 × (boundary) + 1.75 × (regional lymphadenopathy) + 1.18 × (shape) + 1.45 × (posterior acoustic enhancement) + 2.4 × (calcification). The optimal cutoff score was 3, corresponding to 70.2% sensitivity, 93.9% specificity, and 89.6% overall accuracy. The mean areas under the receiver operating characteristic curve (c-statistic) in 10-fold cross-validation was 0.90.

CONCLUSIONS

The constructed predictive scoring model is beneficial for patient counseling under US exam and feasible to provide us the guidance on which kind of needle biopsy should be performed in major salivary gland tumors.

LEVEL OF EVIDENCE

3b Laryngoscope, 131:E157-E162, 2021.

Multiparametric Magnetic Resonance Imaging for the Diagnosis and Differential Diagnosis of Parotid Gland Tumors

The majority of salivary gland tumors occur in the parotid glands. Characterization (ie, benign or malignant, and histological type), location (deep or superficial), and invasion into the neighboring tissues of parotid tumors determine preoperative treatment planning. MRI gives more information than other imaging methods about the internal structure, localization, and relationship with other tissues of parotid tumors. Functional MRI methods (diffusion-weighted imaging, dynamic contrast-enhanced MRI, perfusion-weighted MRI, MR spectroscopy, etc.) have been increasingly used recently to increase the power of radiologists to characterize the tumors. Although they increase the workload of radiologists, the combined use of functional MRI methods improves accuracy in the differentiation of the tumors. There are a wide range of studies in the literature dealing with the combined use of different functional imaging methods in combination with conventional sequences. The aim of the present review is to evaluate conventional and functional/advanced MR methods, as well as multiparametric MRI applications combining them in the diagnosis of parotid gland tumors. Evidence Level: 5 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;52:11-32.

Myxoma arising from the parotid gland

Myxomas can be divided into two groups: those derived from the facial skeleton, and those derived from external skeletal soft tissue. Soft tissue myxomas of the head and neck are uncommon, with fewer than 50 cases reported. In any form and location, myxoma of parotid gland is rare. We report a case of myxoma arising from the left superficial lobe of the parotid gland with good longterm follow-up after superficial parotidectomy with tumor excision. A 49-year-old man was referred to our department of plastic and reconstructive surgery with a painless palpable mass that had persisted in the left mandible angle region for 2 years. Excision of the facial mass and superficial parotidectomy with facial nerve preservation were performed. The biopsy result was myxoma. Long-term follow-up for 22 months showed favorable results without evidence of recurrence but with temporary facial nerve weakness right after the surgery. Myxoma should be considered as a differential diagnosis when benign tumor of the parotid gland is being considered.

Characterization of salivary gland tumours with diffusion tensor imaging

OBJECTIVES

To characterize salivary glands tumours with diffusion tensor imaging.

METHODS

This study was conducted upon 53 patients (aged 18-81 years: mean 37 years) with salivary gland tumours that underwent diffusion tensor imaging was obtained using a single-shot echoplanar imaging sequence with parallel imaging at 1.5 T scanner. 48 slices were obtained, with a thickness of 2.5 mm, with no gap and the total scan duration was 7-8 min. The fractional anisotropy (FA) and the mean diffusivity (MD) value of the salivary gland tumours was calculated and correlated with pathological findings. Image analysis was performed by one radiologist. The receiver operating characteristic curve was drawn to detect the cut-off point of FA and MD used to characterize salivary gland tumours.

RESULTS

The mean FA and MD of malignant salivary gland tumours (n = 17) (0.41 ± 0.07 and 0.89 ± 0.15 × 10-3 mm2 s-1) was significantly different (p = 0.001) than that of benign tumours (n = 36) (0.19 ± 0.07 and 1.28 ± 0.42 × 10-3 mm2 s-1), respectively. Combined FA and MD used to differentiate malignant from benign tumours has an area under the curve (AUC) of 0.974, and an accuracy of 86%. There was a significant difference in FA between Warthin tumours and malignant tumours (p = 0.001). Selection FA of 0.35 to differentiate malignant tumours from Warthin tumours revealed AUC of 0.878 and an accuracy of 80%. There was a significant difference in FA and MD of malignant tumours and pleomorphic adenomas (p = 0.001). Combined FA and MD used to differentiate malignant tumours from pleomorphic adenomas revealed AUC of 0.993, and an accuracy of 93%. There was a significant difference in FA and MD of Warthin tumours and pleomorphic adenomas (p = 0.001). Combined FA and MD used to differentiate Warthin tumours from pleomorphic adenomas revealed AUC of 0.978, and an accuracy of 86%.

CONCLUSIONS

Diffusion-weighed imaging is a promising non-invasive method and it may be useful for the characterization and differentiation of benign and malignant salivary gland tumours.

The Utility of In-Office Ultrasound in the Diagnosis of Parotid Lesions

Objective

To determine whether the use of in-office ultrasound (US) by a head and neck surgeon is a useful adjunct to clinical assessment of parotid lesions and decrease the need of additional imaging, such as magnetic resonance imaging (MRI) or computed tomography (CT).

Study Design

Case series with chart review.

Setting

Tertiary care academic center.

Subjects

Seventy patients presenting with a parotid lesion who obtained an in-office US and ultrasound-guided fine-needle aspiration (USGFNA) from a head and neck surgeon from 2006 to 2015.

Methods

US images were retrospectively reviewed for 70 patients and characterized by a radiologist and a head and neck surgeon.

Results

Of the 70 patients, 6 had US characteristics that demonstrated a statistically significant association with a benign/malignant diagnosis: depth from surface; irregular borders; presence of calcifications, which included either micro- or macro-calcifications; posterior echogenicity enhancement; irregular shape; and homogeneous/heterogeneous echotexture. Imaging was performed prior to referral in 25 cases (35.7%); of those, 17 (68%) were for superficial, small (<2 cm) tumors where prereferral imaging studies did not provide additional information to that obtained with US. Of the 55 patients without MRI or CT performed prior to referral, MRI or positron emission tomography–CT scan was obtained in only 4 patients (7.3%) in cases involving recurrent parotid lesions, large tumors, or workup of a malignant neoplasm.

Conclusions

Several US characteristics individually assist in lesion characterization. In-office US and USGFNA are an appropriate first-line modality in the assessment of parotid lesions, can allow for immediate parotid lesion assessment, and can decrease the need for additional imaging.