Is ultrasound alone sufficient for imaging superficial lobe benign parotid tumours before surgery?

Post-operative Diagnosis of Primary Parotid Tuberculosis in a Patient Initially Diagnosed as Benign Pleomorphic Adenoma

Primary parotid tuberculosis is a well-known but extremely rare entity even in endemic countries. Most of the cases are diagnosed late in the course of illness when the parotid shows features of cold abscess leading to facial disfigurement. Early diagnosis is a clinical challenge due to lack of clinical suspicion as well as absence of clinical or radiological tests suggestive of the disease. Fine needle aspiration cytology features of early tuberculosis can easily be confused with a pleomorphic adenoma. When ultrasound examination of a parotid lesion is atypical, image guided core needle biopsy can be helpful in differentiating these kinds of rare diseases from more common parotid pathologies.

Lessons learnt from the global iodinated contrast media shortage in head and neck imaging

A recent shortage in the global supply of iodinated contrast media (ICM) has required health service providers to review their contrast administration policies and implement strategies to conserve inventory. This article will review the current best practices in head and neck imaging for a variety of common presentations and provide examples where alternative imaging can be considered due to the recent ICM shortage. Ultrasound and MRI techniques can feature heavily in many diagnostic processes in head and neck pathology, and a variety of common presentations can be appropriately investigated through clinical evaluation or naso-endoscopy. In many instances, for the routine assessment of non-acute adult and paediatric head and neck presentations, the use of contrast-enhanced CT can be safely minimised to conserve ICM if required.

Triple Assessment of a Palpable Parotid Lump in "One-Stop" Clinics

Introduction

The National Institute of Clinical Excellence in the UK (NICE) recommended the use of "one-stop" clinics for the assessment and management of head and neck lumps like those established for breast lumps. "One-stop" clinics should follow a triple assessment protocol involving physical examination, radiological imaging and fine-needle aspiration cytology (FNAC).

Methods

A retrospective analysis of 144 patients with suspected parotid tumours from 2005 to 2011 was done. Patients were assessed for individual modalities and compared against the final histological diagnosis. Statistical analysis was used for sensitivity and specificity, as well as positive and negative predictive values. All calculations were performed using SPSS version 16 (Statistical Packages for the Social Sciences, Chicago, IL). A p value of < 0.05 was considered to indicate statistical significance.

Results

A total of 105 patients underwent all the three modalities. Out of them, 93 had imaging that was considered radiologically benign and 12 were reported to have a malignant lesion. Cytologically, 75 were found to have a benign tumour, 13 were malignant, and 17 were considered to be indeterminate. The most common benign neoplasm was pleomorphic adenoma followed by Warthin's tumour. The sensitivity and specificity of triple assessment were 96% (p value 0.878-0.984) and 73% (p value 0.42-0.904), respectively. The positive predictive value was 96% (p value 0.878-0.984) and negative predictive value came out to be 93% (p value 0.42-0.904).

Conclusions

The overall accuracy of triple assessment was found to be 92%. This study concludes that triple assessment is a useful assessment tool to evaluate a patient with parotid lump.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12663-021-01590-5.

Perfusion analysis of benign parotid gland tumors by contrast-enhanced ultrasonography (CEUS)

BACKGROUND

Diagnosis of parotid gland tumors is sometimes challenging due to their diversity and pleomorphic histological appearance. B-scan sonography along with color-coded duplex sonography is the gold standard in the diagnostic workup of these lesions, whereas histopathology is to date the gold standard for the final diagnosis. To date no single imaging technique provides the chance for an art-diagnosis with highly diagnostic accuracy. Contrast enhanced ultrasonography (CEUS) on the other hand provides information of the perfusion down to the capillary level. Currently there are only a few papers published with systematical examination of the perfusion in benign parotid gland tumors and its diagnostic significance.

PATIENTS AND METHODS

One hundred patients with a parotid gland tumor were examined. The examinations included conventional B-scan sonography, color-coded duplexsonography along with contrast enhanced ultrasonography (CEUS). B-scan sonographic parameters, i.e. echogenicity, shape, size, demarcation, and borders of a lesion along with vascularization estimated by color-coded-duplexsonography were analyzed. Analysis of quantitative CEUS parameters was performed using 8 regions of interest (ROI), which were standardized located throughout the entire tumors. The perfusion parameters were analyzed for particular tumor entities. Qualitative CEUS analysis with estimating the perfusion pattern was additionally performed.

RESULTS

Histological examination revealed benign tumors in 92 cases, with pleomorphic adenomas and Warthin´s tumors were the most frequent entities. Malignant conditions were found in 8 cases. CEUS revealed a centripetal perfusion pattern in malignant tumors significantly more frequently than in benign tumors. CEUS showed a significant heterogenic perfusion in all tumors, with a higher perfusion in the medial parts of the tumors and in some cases also in the center. Perfusion patterns of PA and WT were different. WT displayed centrifugal, centripetal, and central diffuse perfusion more often than PA, whereas in PA perfusion often was limited to the capsule or periphery. Oncocytoma had the highest perfusion values. Intraglandular cysts showed no intralesional perfusion.

CONCLUSIONS

CEUS analysis in different parts of benign tumors revealed a significant heterogeneity in tumor perfusion. Some perfusion pattern could be identified which might be characteristic for particular lesions. Based on this, the diagnostic accuracy of CEUS in the differential diagnosis of parotid gland tumors can be increased. In particular, the perfusion analysis within the tumors using ROIs located standardized throughout the entire tumor provides additional information which are important for the art diagnosis and in differentiation of tumor entity.

An update on extracapsular dissection for the management of parotid gland pleomorphic adenoma

Superficial parotidectomy has been the gold standard for surgical removal of benign mobile parotid gland tumours. The comparatively newer technique of extracapsular dissection, which involves careful dissection of the tumour itself without the need for formal gland excision, has gained popularity in recent years. Tumours can be removed via smaller incision, and the technique reduces the risk of Frey's syndrome (gustatory sweating) and hollowing at the site of surgery. The risk of facial nerve damage can also be lower with extracapsular dissection. If done carefully, the incidence of tumour recurrence, particularly for pleomorphic adenomas, is comparable with formal parotidectomy. We provide a brief update overview of the current evidence for extracapsular dissection in the treatment of benign parotid tumours and include several meta-analyses which provide evidence for the safety of the technique. We have also included our audited results of over 100 recent extracapsular dissections, with 0% incidence of permanent facial nerve weakness, reported Frey's syndrome and recurrence rates over the last 5 years.

[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.

Observation Rather than Surgery for Benign Parotid Tumors: Why, When, and How

Surgery is the preferred treatment of benign parotid lesions, but it carries a risk of complications. Therefore, the approach toward the surgery of these lesions should seek to avoid complications. There are no guidelines or recommendations for when not to operate. Integration of comorbidities and other factors shift the scales from surgery toward observation in a small subset of patients presenting with parotid tumors. When observation is chosen, the patient should be followed frequently and cautiously, and the surgeon should be prepared to change strategy to surgical excision if in doubt.

A multicenter validation of the revised version of the Milan system for reporting salivary gland cytology (MSRSGC)

INTRODUCTION

Fine-needle aspiration cytology (FNAC) is a basic step in the diagnosis of salivary gland tumors that have a wide variety of histological types. The recent Milan system for reporting salivary gland cytopathology (MSRSGC) can correlate the risk of malignancy with precise cytological features. A revised version was recently proposed to improve the surgical relevance and facilitate uniform management.

MATERIAL AND METHODS

A multicenter study retrospectively used the original and revised MSRSGC criteria to classify a series of patients who received surgery after FNAC.

RESULTS

We enrolled 503 patients from three tertiary centers. The risk of malignancy for the MSRSGC resulted 19.5% in cat. I, 14.3% in cat. II, 17.6% in cat. III, 3.6% in cat. IVa, 24.6% in cat. IVb, 66.7% in cat. V, and 96.8% in cat. VI. The results from the revised MSRSGC were consistent with the original values.

CONCLUSION

The MSRSGC is a promising classification system. In our opinion, the revised version of the MSRSGC supplements FNAC with some crucial clinical information and can better identify the appropriate treatment in each category.

Recent advances in the histopathological assessment of salivary disease

BACKGROUND

Salivary gland disease includes a wide range of unique and rare conditions that are treated by ear, nose and throat (ENT), oral and maxillofacial surgeons (OMFS) and oral medicine specialists. Histopathological diagnosis is pivotal to making a diagnosis and treatment planning. There is a vast range of conditions and controversies in the histopathological assessment of salivary gland diseases. Most colleagues in oral pathology and oral medicine work closely with the OMFS but might have missed some of the recent articles published by the speciality.

METHODS

We reviewed articles thought to be relevant to oral medicine and pathology specialists published over an 8-year period between 2012 and 2019 in the leading British Journal of Oral and Maxillofacial Surgery (BJOMS).

RESULTS

A total of 44 published articles relating to the histopathology of salivary glands disease were selected. Papers were published on population studies, benign and malignant tumours, sialadenitis, metastasis to the parotid gland and cytology. The publication type and numbers published were as follows: review (n = 9), meta-analysis/randomised controlled study (n = 1), retrospective study (n = 10) and case report/technical notes (n = 23).

CONCLUSIONS

The greatest proportion of publications published in BJOMS were case reports. This emphasises the paucity of consensus and the need for development in this field. Salivary gland disease remains an area with many controversies and would benefit from further research.

Is fine needle aspiration biopsy reliable in the diagnosis of parotid tumors? Comparison of preoperative and postoperative results and the factors affecting accuracy

Introduction

Fine needle aspiration biopsy is a valuable tool in preoperative evaluation of head and neck tumors. However, its accuracy in management of salivary gland tumors is debatable.

Objective

We aimed to investigate the efficacy and the accuracy of fine needle aspiration biopsy in parotid gland tumors.

Methods

Patients who underwent parotidectomy between January 2008 and June 2017 due to parotid gland tumor were examined retrospectively. Patients with both preoperative fine needle aspiration biopsy and postoperative surgical pathologies were included. Preoperative fine needle aspiration biopsy was categorized as benign, malignant or suspicious for malignancy. Surgical pathology was grouped as benign or malignant. Surgical pathology was compared with fine needle aspiration biopsy, and sensitivity, specificity, accuracy and agreement between both tests were investigated.

Results

217 cases were evaluated and 23 cases were excluded because the fine needle aspiration biopsy diagnosis was non-diagnostic or unavailable. 194 cases were included. The mean age of the patients was 47.5 ± 15.88 (7–82). There were 157 benign, 37 malignant cases in fine needle aspiration biopsy, 165 benign and 29 malignant cases in surgical pathology. The most common benign tumor was pleomorphic adenoma (43.3%), and malignant tumor was mucoepidermoid carcinoma (4.13%). The diagnostic accuracy for fine needle aspiration biopsy when detecting malignancy was 86.52%. Sensitivity and specificity were 68.96% and 89.63% respectively. Positive predictive value was 54.05% and negative predictive value was 94.23%. There was moderate agreement between fine needle aspiration biopsy and surgical pathology (κ = 0.52). The sensitivity was 54.54% in tumors less than 2 cm while 77.77% in larger tumors. In tumors extending to the deep lobe, sensitivity was 80%.

Conclusion

Fine needle aspiration biopsy is an important diagnostic tool for evaluating parotid gland tumors. It is more accurate in detecting benign tumors. In tumors greater than 2 cm and extending to the deep lobe, the sensitivity of fine needle aspiration biopsy is high. The use of fine needle aspiration biopsy in conjunction with clinical and radiological evaluation may help to reduce false positive and false negative results.

Surgeon-performed ultrasound for the assessment of parotid masses

BACKGROUND

Studies on parotid gland ultrasound assessments performed specifically by surgeons are seldom reported.

METHODS

Retrospective series of a single academic surgeon experience, analyzing 70 new parotid masses with evaluable preoperative SP-US characteristics, location measurements, and perioperative events.

RESULTS

31/70 masses were malignant. SP-US characteristics significantly associated with both malignancy and positive margins included extraparenchymal extension, irregular borders, hypervascularity, infiltration, and the lack of deep enhancement. The larger the skin-to-deep-aspect-of-tumor distance, the more likely the tumor was deep to FN. For the 39 cytologically benign tumors, neither CT nor MRI provided additional information to change management except for full delineation of parapharyngeal space extension in 2 cases.

CONCLUSION

SP-US can help predict parotid mass benignity/malignancy, positive margin risk, and tumor relation to FN. SP-US may be used as the sole imaging in cytologically benign tumors unless the deep tumor extent cannot be identified.

Contemporary Management of Benign and Malignant Parotid Tumors

To report the standard of care, interesting new findings and controversies about the treatment of parotid tumors. Relevant and actual studies were searched in PubMed and reviewed for diagnostics, treatment and outcome of both benign and malignant tumors. Prospective trials are lacking due to rarity of the disease and high variety of tumor subtypes. The establishment of reliable non-invasive diagnostics tools for the differentiation between benign and malignant tumors is desirable. Prospective studies clarifying the association between different surgical techniques for benign parotid tumors and morbidity are needed. The role of adjuvant or definitive radiotherapy in securing loco-regional control and improving survival in malignant disease is established. Prospective clinical trials addressing the role of chemotherapy/molecular targeted therapy for parotid cancer are needed. An international consensus on the classification of parotid surgery techniques would facilitate the comparison of different trials. Such efforts should lead into a clinical guideline.

Gray scale and doppler ultrasonography features of the carcinoma ex pleomorphic adenoma

OBJECTIVES

For lesions in the salivary glands, ultrasonography (US) is an ideal tool for initial assessment. The aim of this study was to characterize and differentiate between the Gray scale and Doppler US findings of intracapsular carcinoma ex pleomorphic adenoma (Ic-CxPA) and invasive carcinoma ex pleomorphic adenoma (Inv-CxPA).

METHODS

A total of 87 patients (89 lesions) with histopathologically proven CxPA underwent US examination. The following characteristics were assessed on US images: size, shape, border, echogenicity, echo texture, posterior echo, vascularity, and regional lymph node enlargement. One-way analysis of variance (ANOVA), nonparametric test, Fisher's exact test, chi-square test and receiver operating characteristic (ROC) curve were used for the analyses of the US findings of Ic-CxPAs and Inv-CxPAs.

RESULTS

We found that on US images, nearly all Ic-CxPAs (10/11) and a few of Inv-CxPAs (17/78) showed benign features, such as a regular shape, a well-defined border, and enhancement of posterior echo, while most Inv-CxPAs (61/78) showed one or more following features: an irregular shape, an ill-defined border, and lack of enhancement of posterior echo.

CONCLUSIONS

Ic-CxPAs tended to exhibit benign features, whereas most Inv-CxPAs tended to exhibit one or more invasive features. US can provide strong evidence in differentiating Inv-CxPAs from Ic-CxPAs.

Benign Parotid Tumors

This article reviews the epidemiology, embryology, risk factors, clinical presentation, diagnostic work-up, and basic management principles for the more common benign parotid neoplasms. The various histopathologies are also discussed and summarized.

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.

Initial Experience With Ultrasound Elastography for Diagnosis of Major Salivary Gland Lesions

OBJECTIVES

The aim of this study was to evaluate the usefulness of ultrasound elastography, including conventional strain elastography, acoustic radiation force impulse (ARFI)-induced strain elastography, and point shear wave elastography (SWE) for diagnosis of major salivary gland lesions.

METHODS

Forty major salivary gland lesions underwent conventional sonography, conventional strain elastography, ARFI strain elastography, and point SWE before surgery or biopsy. The diagnostic performances of the sonographic and elastographic techniques were assessed with reference to histopathologic results.

RESULTS

There were 32 benign (7 Warthin tumors, 17 pleomorphic adenomas, and 8 other benign lesions) and 8 malignant (1 squamous carcinoma, 2 metastases, 2 mucoepidermoid carcinomas, 1 anaplastic carcinoma, and 2 malignant lymphomas) major salivary gland lesions on pathologic analysis. No conventional sonographic features or conventional strain elastographic scores were found to be associated with malignancy (all P > .05). The ARFI strain elastographic scores between benign and malignant lesions were statistically different (P = .032) and an ARFI strain elastographic score of 4 or greater was highly predictive of malignancy (P= .025). An ARFI strain elastographic score of greater than 3 achieved specificity of 81.3% (26 of 32) and sensitivity of 62.5% (5 of 8) in differentiating benign from malignant lesions. The shear wave velocity on point SWE did not show a significant difference in distinguishing between malignant and benign lesions (6.07 versus 4.43 m/s; P > .05). However, Warthin tumors had a trend to show lower shear wave velocities compared with pleomorphic adenomas (2.84 versus 5.27 m/s; P = .024).

CONCLUSIONS

Acoustic radiation force impulse strain elastography may be potentially useful for diagnosing major salivary gland lesions, whereas conventional strain elastography and point SWE are not helpful.

Contemporary management of benign parotid tumours - the increasing evidence for extracapsular dissection

Benign parotid tumours have historically often been managed surgically by superficial parotidectomy. While this approach usually gives a generous cuff of surrounding normal parotid tissue to increase tumour margins, it requires a much larger incision than the increasingly used extracapsular dissection (ECD) technique. Furthermore, superficial parotidectomy can result in marked facial hollowing, Frey syndrome and an increased risk of both temporary and permanent facial nerve weakness. ECD has been popularised as a safe alternative to parotidectomy primarily for the removal of mobile, benign parotid tumours with safe outcomes and reduced risk to the facial nerve. In this article, we review the growing body of evidence for ECD and include our own experience confirming the move away from superficial parotidectomy in contemporary practice for the treatment of benign parotid tumours.

Biopsy of parotid masses: Review of current techniques

Definitive diagnosis of parotid gland masses is required optimal management planning and for prognosis. There is controversy over whether fine needle aspiration cytology (FNAC) or ultrasound guided core biopsy (USCB) should be the standard for obtaining a biopsy. The aim of this review is to assess the current evidence available to assess the benefits of each technique and also to assess the use of intra-operative frozen section (IOFS). Literature searches were performed using pubmed and google scholar. The literature has been reviewed and the evidence is presented. FNAC is an accepted and widely used technique. It has been shown to have variable diagnostic capabilities depending on centres and experience of staff. USCB has a highly consistent diagnostic accuracy and can help with tumour grading and staging. However, the technique is more invasive and there is a question regarding potential for seeding. Furthermore, USCB is less likely to be offered as part of a one-stop clinic. IOFS has no role as a first line diagnostic technique but may be reserved as an adjunct or for lesions not amenable to percutaneous biopsy. On balance, USCB seems to be the method of choice. The current evidence suggests it has superior diagnostic potential and is safe. With time, USCB is likely to supplant FNAC as the biopsy technique of choice, replicating that which has occurred already in other areas of medicine such a breast practice.

Feasibility of a novel classification for parotid gland cytology: A retrospective review of 512 cytology reports taken from 4 United Kingdom general hospitals

BACKGROUND

A novel classification for parotid cytology has been previously proposed. The purpose of this study was to assess the feasibility and clinical relevance of this classification.

METHOD

Between 2010 and 2013, cytology reports from 4 United Kingdom general hospitals were retrospectively classified and compared to histological and clinical outcomes.

RESULTS

Based on the cytology reports of 512 patients, we revised our previous "P" system to a "Sal" (salivary) classification to encompass all cytologic outcomes. The percentage of patients with a final diagnosis of malignancy according to each category heading were: Sal 1 (inadequate) 7.9%; Sal 2I (nonneoplastic) 10%; Sal 2N (benign neoplastic) 1.4%; Sal 3 (atypical) 20.4%; Sal 4 (suspicious) 52.6%; Sal 5P (primary salivary gland malignancy) 71.4%; Sal 5NOS (malignancy not otherwise specified) 100%; and Sal 5M (metastasis) 91.7%.

CONCLUSION

By stratifying the probability of encountering a malignant neoplasm, the classification could guide clinical management decisions. A future prospective study is warranted. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1708-1716, 2016.

The efficacy of magnetic resonance imaging and color Doppler ultrasonography in diagnosis of salivary gland tumors

Background and aims. Although salivary gland tumors are not very common, early diagnosis and treatment is crucial because of their proximity to vital organs, and therefore, determining the efficacy of new imaging procedures becomes important. This study aimed to evaluate the efficacy of magnetic resonance imaging (MRI) and color doppler ultrasonography parameters in the diagnosis and differentiation of benign and malignant salivary gland tumors.

Materials and methods. In this cross-sectional study, color doppler ultrasonography and MRI were performed for 22 patients with salivary gland tumor. Demographic data as well as MRI, color doppler ultrasonography, and surgical parameters including tumor site, signal in MRI images, ultrasound echo, tumor border, lymphadenopathy, invasion, perfusion, vascular resistance index (RI), vascular pulse index (PI) were analyzed using Chi-square test, Fisher's exact test, and independent t-test.

Results. The mean age of patients was 46.59±13.97 years (8 males and 14females). Patients with malignant tumors were older (P < 0.01). The most common tumors were pleomorphic adenoma (36.4%), metastasis (36.4%), and mucoepidermoid carcinoma (9%). Nine tumors (40.9%) were benign and 13 (59.1%) were malignant. The overall accuracy of MRI and color doppler ultrasonography in determining tumor site was 100% and 95%, respectively. No significant difference observed between RI and PI and the diagnosis of tumor.

Conclusion. Both MRI and ultrasonography have high accuracy in the localization of tumors. Well-identified border was a sign of benign tumors. Also, invasion to adjacent structures was a predictive factor for malignancy.

Ultrasound histogram assessment of parotid gland injury following head-and-neck radiotherapy: a feasibility study

Xerostomia (dry mouth), resulting from radiation damage to the parotid glands, is one of the most common and distressing side effects of head-and-neck cancer radiotherapy. A noninvasive, objective imaging method to assess parotid injury is lacking, but much needed in the clinic. Therefore, we investigated echo histograms to quantitatively evaluate the morphologic and microstructural integrity of the parotid glands. Six sonographic features were derived from the echo-intensity histograms to assess the echogenicity, homogeneity and heterogeneity of the parotid gland: (1) peak intensity value (I(peak)), (2) -3-dB intensity width (W(3-dB)), (3) the low (<50% I(peak)) intensity width (W(low)), (4) the high (>50% I(peak)) intensity width (W(high)), (5) the area of low intensity (A(low)) and (6) the area of high intensity (A(high)). In this pilot study, 12 post-radiotherapy patients and seven healthy volunteers were enrolled. Significant differences (p < 0.05) were observed in four sonographic features between 24 irradiated and 14 normal parotid glands. In summary, we developed a family of sonographic features derived from echo histograms and demonstrated the feasibility of quantitative evaluation of radiation-induced parotid-gland injury.