Adding automated decision-tree models to multiparametric MRI for parotid tumours improves clinical performance.

PURPOSE: Therapeutic management of parotid gland tumours depends on their histological type. To aid its characterisation, we sought to develop automated decision-tree models based on multiparametric magnetic resonance imaging (MRI) parameters and to evaluate their added diagnostic value compared with morphological sequences. METHODS: 206 MRIs from 206 patients with histologically proven parotid gland tumours were included from January 2009 to January 2018. Multiparametric MRI findings (including parameters derived from diffusion-weighted imaging [DWI] and dynamic contrast-enhanced [DCE]) were used to build predictive classification and regression tree (CART) models for each histological type. All MRIs were read twice: first, based on morphological sequence findings only, and second, with the addition of multiparametric sequences and CART findings. The diagnostic performance between these two readings was compared using ROC curves. RESULTS: Compared to morphological sequences alone, the addition of multiparametric analysis significantly increased the diagnostic performance for all histological types (p < 0.001 to p = 0.011), except for lymphomas, where the increase was not significant (AUC 1.00 vs. 0.99, p = 0.066). ADCmean was the best parameter to identify pleomorphic adenomas, carcinomas and lymphomas with respective cut-offs of 1.292 × 10-3 mm2/s, 1.181 × 10-3 mm2/s and 0.611 × 10-3 mm2/s, respectively. × 10-3 mm2/s. The mean extracellular-extravascular space coefficient was the best parameter to Warthin tumours from the others, with a cut-off of 0.07. CONCLUSIONS: The addition of decision tree prediction models based on multiparametric sequences improves the non-invasive diagnostic performance of parotid gland tumours. ADC and extracellular-extravascular space coefficient are the two best parameters for decision making.

Diagnostic imaging of parotid gland oncocytoma: a pictorial review with emphasis on ultrasound assessment.

Parotid gland oncocytoma (PGO) is a rare benign epithelial tumor that usually occurs in the elderly population. The most common clinical presentation is a painless, slow-growing, non-tender, lobulated, and mobile mass. Histologically, it is composed of monotonous sheets of epithelial cells (oncocytes) with a central scar. The cross-sectional appearance is not specific, and it overlaps with other parotid lesions. On ultrasound (US), oncocytoma appears as an ovoid, well-defined, homogeneous, and hypoechoic lesion. Cystic and hemorrhagic areas as well as intralesional fat may be observed. Doppler analysis shows intratumoral vessels, sometimes with a spoke-wheel pattern. The peak systolic flow is high (up to 100 cm/sec). Furthermore, oncocytoma is avid of FDG on a PET scan, as well as a malignant tumor. Thus, a combined clinical, imaging, and pathologic assessment is essential to establish the most accurate diagnosis and plan the best treatment. US, combined with Doppler techniques, can play an important role in suggesting the diagnosis and confirming it through percutaneous sampling. The purpose of this review is to show the imaging findings in PGO, with special emphasis on the US appearance.

Determination of optical properties of human tissues obtained from parotidectomy in the spectral range of 250 to 800 nm.

The optical properties of human tissues are an important parameter in medical diagnostics and therapy. The knowledge of these parameters can encourage the development of automated, computer-driven optical tissue analysis methods. We determine the absorption coefficient µa and scattering coefficient µs' of different tissue types obtained during parotidectomy in the wavelength range of 250 to 800 nm. These values are determined by high precision integrating sphere measurements in combination with an optimized inverse Monte Carlo simulation. To conserve the optical behavior of living tissues, the optical spectroscopy measurements are performed immediately after tissue removal. Our study includes fresh samples of the ear, nose, and throat (ENT) region, as muscle tissue, nervous tissue, white adipose tissue, stromal tissue, parotid gland, and tumorous tissue of five patients. The measured behavior of adipose corresponds well with the literature, which sustains the applied method. It is shown that muscle is well supplied with blood as it features the same characteristic peaks at 430 and 555 nm in the absorption curve. The parameter µs' decreases for all tissue types above 570 nm. The accuracy is adequate for the purposes of providing µa and µs' of different human tissue types as muscle, fat, nerve, or gland tissue, which are embedded in large complex structures such as in the ENT area. It becomes possible for the first time to present reasonable results for the optical behavior of human soft tissue located in the ENT area and in the near-UV, visual, and near-infrared areas.

High-Resolution MRI Microscopy Coil Assessment of Parotid Masses.

The goal of this study was to determine whether high-resolution magnetic resonance imaging (MRI) microscopy coil imaging can improve the depiction parotid masses. A total of 14 parotid masses, including 7 salivary neoplasms, 2 abnormal lymph nodes, and 5 benign cystic lesions were imaged with T2-weighted and fat-suppressed postcontrast T1-weighted sequences using a 47-mm diameter microscopy coil in addition to conventional MRI sequences acquired with a conventional head and neck neurovascular coil. Compared to conventional parotid MRI sequences, microscopy coil images provided better definition of the margins of neoplasms, provide more detailed definition of lymph node morphology, and better depict certain cyst contents in the superficial portions of the parotid gland. The microscopy coil images provided significantly better definition of lesions and surrounding tissues within the superficial parotid gland with resptect to the deep parotid gland structures due to loss of signal. Furthermore, the fat-suppressed postcontrast T1-weighted microscopy coil images were significantly better than the corresponding T2-weighted images for delineating the superficial parotid gland. Ultimately, the microscopy coil sequences added over 10 minutes to the examination time.

18F-FDG PET/CT for staging and response assessment of primary parotid MALT lymphoma with multiple sites involvement: A case report.

RATIONALE: Mucosa-associated lymphoid tissue (MALT) lymphoma is an extranodal low-grade B cell lymphoma that generally exhibits an indolent clinical course. Currently, the application of F-fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG PET/CT) in MALT lymphoma is still controversial. Herein, we reported a case of using F-FDG PET/CT for staging and response assessment of primary parotid MALT lymphoma with multiple sites involvement. As far as we know, there are no similar case reports have been published before. PATIENT CONCERNS: A 71-year-old woman, who received mass resection twice during the past 2 years due to the repeatedly relapse of facial painless masses and diagnosed as reactive lymphoid hyperplasia by pathologic tests. However, the pathological diagnosis was then changed to primary parotid MALT lymphoma after left parotidectomy operation because of a new mass found in her left parotid. Four months later, the right eyelid of the patient swelled with a blurred vision. Then, F-FDG PET/CT scan was performed for staging, and the imaging results showed an abnormal increase of F-FDG uptake in multiple sites including bilateral ocular adnexal, lungs, pleura, occipital subcutaneous tissue, left kidney, and lymph nodes. DIAGNOSES: The patient was diagnosed as primary parotid MALT lymphoma with Ann Arbor stage of IVA based on the F-FDG PET/CT findings. INTERVENTIONS: The patient received 4 cycles of chemotherapy, followed by a partial metabolic remission (PMR), which was determined by interim F-FDG PET/CT, and finally additional 2 cycles of chemotherapy. OUTCOMES: The follow-up study illustrated that the patient had been alive and doing well at 12 months after chemotherapy. LESSONS: Although MALT lymphoma normally localizes in the primary organs, the involvement of multiple organs and lymph nodes is possible. The use of PET/CT demonstrated significant clinical values in the accurate staging and response assessment of F-FDG-avid MALT lymphoma. It is potentially useful for indicating the progress and transformation of MALT lymphoma, and guidance in localization of pathological biopsy. It is also helpful for clinicians to choose reasonable treatment strategy and improve the prognosis of patients.

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.

Beamlet based direct aperture optimization for MERT using a photon MLC.

PURPOSE: A beamlet based direct aperture optimization (DAO) for modulated electron radiotherapy (MERT) using photon multileaf collimator (pMLC) shaped electron fields is developed and investigated. METHODS: The Swiss Monte Carlo Plan (SMCP) allows the calculation of dose distributions for pMLC shaped electron beams. SMCP is interfaced with the Eclipse TPS (Varian Medical Systems, Palo Alto, CA) which can thus be included into the inverse treatment planning process for MERT. This process starts with the import of a CT-scan into Eclipse, the contouring of the target and the organs at risk (OARs), and the choice of the initial electron beam directions. For each electron beam, the number of apertures, their energy, and initial shape are defined. Furthermore, the DAO requires dose-volume constraints for the structures contoured. In order to carry out the DAO efficiently, the initial electron beams are divided into a grid of beamlets. For each of those, the dose distribution is precalculated using a modified electron beam model, resulting in a dose list for each beamlet and energy. Then the DAO is carried out, leading to a set of optimal apertures and corresponding weights. These optimal apertures are now converted into pMLC shaped segments and the dose calculation for each segment is performed. For these dose distributions, a weight optimization process is launched in order to minimize the differences between the dose distribution using the optimal apertures and the pMLC segments. Finally, a deliverable dose distribution for the MERT plan is obtained and loaded back into Eclipse for evaluation. For an idealized water phantom geometry, a MERT treatment plan is created and compared to the plan obtained using a previously developed forward planning strategy. Further, MERT treatment plans for three clinical situations (breast, chest wall, and parotid metastasis of a squamous cell skin carcinoma) are created using the developed inverse planning strategy. The MERT plans are compared to clinical standard treatment plans using photon beams and the differences between the optimal and the deliverable dose distributions are determined. RESULTS: For the idealized water phantom geometry, the inversely optimized MERT plan is able to obtain the same PTV coverage, but with an improved OAR sparing compared to the forwardly optimized plan. Regarding the right-sided breast case, the MERT plan is able to reduce the lung volume receiving more than 30% of the prescribed dose and the mean lung dose compared to the standard plan. However, the standard plan leads to a better homogeneity within the CTV. The results for the left-sided thorax wall are similar but also the dose to the heart is reduced comparing MERT to the standard treatment plan. For the parotid case, MERT leads to lower doses for almost all OARs but to a less homogeneous dose distribution for the PTV when compared to a standard plan. For all cases, the weight optimization successfully minimized the differences between the optimal and the deliverable dose distribution. CONCLUSIONS: A beamlet based DAO using multiple beam angles is implemented and successfully tested for an idealized water phantom geometry and clinical situations.

Assessment of second tier lymph nodes in melanoma and implications for extent of elective neck dissection in metastatic cutaneous malignancy of the parotid.

BACKGROUND: The parotid is the commonest site of cutaneous metastases in the head and neck. The role and extent of neck dissection in patients with parotid metastatic cutaneous malignancy remains controversial. METHODS: We reviewed the lymphoscintigraphy and single photon emission CT (SPECT) of patients with melanoma who had a sentinel node in the parotid to determine the second tier cervical lymph nodes. RESULTS: Levels II and III cervical nodes make up 82% of second tier lymph nodes for the parotid, and levels IV and V, 12% and 4%, respectively. Second tier lymph nodes isolated to levels I, IV, or V, bypassing levels II and III, occurred in only 2% of cases. CONCLUSION: The risk of harboring occult metastasis in levels I, IV, and V when levels II and III are negative is low. Levels II and III neck dissection is likely to be an effective staging procedure in patients with isolated parotid metastases.

The ultrasound examination in assessment of parotid gland tumours: the novel graphic diagram.

Ultrasound is one of the main diagnostic techniques for parotid gland tumours. It is inexpensive, non-invasive and widely available. However, interpretation of the images is highly subjective and constitutes a major limitation. To overcome this problem, we developed a graphic diagram to provide a standardised template that can be used for more precise identification of the tumour localisation within the parenchyma of the parotid gland. This new diagram may be used to provide surgeons with an improved and more objective localisation of the tumour. The study included 237 patients who underwent surgery for parotid tumours. To obtain the precise spatial location of the tumours, three topographic coordinates of tumour location in the coronal, sagittal and transversal plane were marked preoperatively during sonography within the parenchyma of the parotid gland. The localisation identified ultrasonically was then compared to the postsurgical report: 197 (83 %) tumours were found within the superficial lobe of the parotid gland and 40 (17 %) within the deep lobe of the parotid gland. In 157 (66 %) cases, tumours were found within the lower pole of the parotid gland, and in 64 (27 %) at the level of earlobe and its insertion, 16 (7 %) tumours were located at the level of the tragus and above it. Based on the results obtained, a graphic diagram of parotid gland tumour locations was developed.

Role of ultrasound in the assessment of benignity and malignancy of parotid masses.

OBJECTIVES: This study aimed to investigate the value of ultrasound in the identification of benign and malignant parotid masses. METHODS: Data of 189 patients with parotid gland masses undergoing ultrasound-guided fine-needle aspiration (FNA), core biopsy or surgery were reviewed retrospectively and the presumed sonographic diagnoses were compared with the histopathology. The sensitivity, specificity and accuracy of sonographic diagnoses were assessed and the sonographic characteristics of those lesions, including shape, margin, echogenicity, echotexture and vascularization, were studied. RESULTS: Of the 189 patients, the final pathological diagnosis included 18 malignant tumours and 171 benign masses; the presumed sonographic diagnoses showed 165 cases as benign and probably benign masses (11 cases were confirmed malignant, 154 cases benign) and 24 cases were diagnosed as probably malignant and malignant masses (7 cases were confirmed malignant, 17 cases benign). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of ultrasound for the diagnosis of parotid gland masses were 38.9%, 90.1%, 29.2%, 93.3% and 85.2%, respectively, and accuracy for malignant masses was 20%. The sonographic characteristics of parotid masses between benign and malignant lesions had no significant differences. The parotid gland masses in this study included pleomorphic adenoma, Warthin's tumour, retention cyst, haemangiomas, chronic granuloma, lymphoma, fibrolipoma, abscess, basal cell adenoma, oncocytoma, lymphatic tuberculosis, myoepithelioma, neurilemmoma, mucoepidermoid carcinoma, adenoid cystic carcinoma, alveolar soft part sarcoma and retinal blastoma (metastasis). CONCLUSIONS: It is challenging to use sonography for differentiating between benign and malignant parotid gland masses. To make a definite diagnosis, ultrasound-guided FNA or core biopsy is advocated.

High resolution ultrasound assessment of the parotid gland.

A variety of neoplastic and non-neoplastic conditions may present with parotid swelling. It is rarely possible to predict the nature of a swelling on clinical grounds alone and accurate imaging is necessary for further assessment. The parotid glands are superficial structures and are readily amenable to high resolution ultrasound examination. Ultrasound is able to: differentiate possible benign from malignant neoplasms; demonstrate whether a palpable lesion arises within the parotid gland, or is periparotid in location; and identify those entities that may not need surgical intervention. In this article the sonographic features of a range of parotid pathologies are reviewed and examples illustrated and the role of ultrasound in parotid assessment is discussed.

Salivary gland tumours: is colour Doppler imaging of added value in their preoperative assessment?

Using a Toshiba SSA-270A Colour Duplex Scanner, 15 patients with suspected parotid and submandibular gland tumours had preoperative duplex scanning done. Peak systolic doppler shifts (fmax) were recorded and their vascularity was also subjectively scored. There were no arteries identified within the substance of contralateral normal glands. All recordings were analysed retrospectively and an independent histological assessment of tumours was made. Pleomorphic adenomas (n = 9) had a median peak systolic frequency (fmax) of 0.8 kHz, while adenolymphomas (n = 4) had a fmax of 1.65 and the two malignant tumours had fmax of 4.5 (P = 0.007 Kruskal-Wallis test). There appears to be a strong correlation between the fmax and the subjective vascular score (Corr 0.92). Colour duplex scanning is a non-invasive procedure which may be of help in the preoperative assessment of salivary gland tumours.

[The use of computed tomography in assessing parotid masses]. / Aplicación de la tomografía computerizada en la valoración de las masas parotídeas.

Thirty-one patients with suspected parotid masses have been studied by computed tomography (CT) without and with contrast to demonstrate the existence of this and to value possible relation between degrees of malignancy and the morphological characteristics of the masses.

Preoperative assessment of parotid masses: a comparative evaluation of radiologic techniques to histopathologic diagnosis.

A double-blind, retrospective analysis of 110 sequentially operated parotid masses compared the usefulness of preoperative radiologic evaluation to histopathologic diagnosis. The radiologic assessment included 25 sialograms, 162 computed tomography scans, and 10 nuclear magnetic resonance images. The diagnosis is influenced by the following four parameters of computed tomography: tumor borders, density, homogeneity, and enhancement. Well-defined borders, a homogeneous appearance, and high density strongly favor the diagnosis of a benign tumor or a low-grade malignancy (96.7%). Ill-defined tumor borders, heterogeneity, and high density indicate mainly a high-grade or recurrent malignancy (68.8%). Ill-defined borders, a heterogeneous appearance, and mixed density identify a lymphoepithelial lesion, lymphangioma, or sialoadenitis (100%). Sialography is cost effective in the evaluation of lymphoepithelial lesions. Computed tomography sialography offers no advantages over computed tomography with intravenous contrast. High-resolution computed tomography with intravenous contrast is highly sensitive for tumor detection (97%). Magnetic resonance imaging is complementary or superior to computed tomography (100%).

A comparison of computed tomography and ultrasound in the assessment of parotid masses.

Computed tomography (CT) and ultrasonography were compared in the evaluation of parotid masses. The findings in 18 patients are presented. Both techniques proved equally effective at locating and predicting malignancy in lesions confined to the superficial lobe of the gland. Tumours in the deep lobe, medial to the ramus of the mandible and those extending beyond the confines of the gland were more reliably assessed by CT. It is recommended that CT is reserved for such problems, and that ultrasonography should be the initial investigation for the evaluation of parotid masses.