Identification of circRNAs expression profiles and functional networks in parotid gland of type 2 diabetes mouse.

BACKGROUND: Circular RNAs (circRNAs) are a novel kind of non-coding RNAs proved to play crucial roles in the development of multiple diabetic complications. However, their expression and function in diabetes mellitus (DM)-impaired salivary glands are unknown. RESULTS: By using microarray technology, 663 upregulated and 999 downregulated circRNAs companied with 813 upregulated and 525 downregulated mRNAs were identified in the parotid glands (PGs) of type2 DM mice under a 2-fold change and P < 0.05 cutoff criteria. Gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) analysis of upregulated mRNAs showed enrichments in immune system process and peroxisome proliferator-activated receptor (PPAR) signaling pathway. Infiltration of inflammatory cells and increased inflammatory cytokines were observed in diabetic PGs. Seven differently expressed circRNAs validated by qRT-PCR were selected for coding-non-coding gene co-expression (CNC) and competing endogenous RNA (ceRNA) networks analysis. PPAR signaling pathway was primarily enriched through analysis of circRNA-mRNA networks. Moreover, the circRNA-miRNA-mRNA networks highlighted an enrichment in the regulation of actin cytoskeleton. CONCLUSION: The inflammatory response is elevated in diabetic PGs. The selected seven distinct circRNAs may attribute to the injury of diabetic PG by modulating inflammatory response through PPAR signaling pathway and actin cytoskeleton in diabetic PGs.

Multispectral optoacoustic tomography of benign parotid tumors in vivo: a prospective observational pilot study.

Parotid lumps are a heterogeneous group of mainly benign but also malignant tumors. Preoperative imaging does not allow a differentiation between tumor types. Multispectral optoacoustic tomography (MSOT) may improve the preoperative diagnostics. In this first prospective pilot trial the ability of MSOT to discriminate between the two most frequent benign parotid tumors, pleomorphic adenoma (PA) and Warthin tumor (WT) as well as to normal parotid tissue was explored. Six wavelengths (700, 730, 760, 800, 850, 900 nm) and the parameters deoxygenated (HbR), oxygenated (HbO2), total hemoglobin (HbT), and saturation of hemoglobin (sO2) were analyzed. Ten patients with PA and fourteen with WT were included (12/12 female/male; median age: 51 years). For PA, the mean values for all measured wave lengths as well as for the hemoglobin parameters were different for the tumors compared to the healthy parotid (all p < 0.05). The mean MSOT parameters were all significantly higher (all p < 0.05) in the WT compared to healthy parotid gland except for HbT and sO2. Comparing both tumors directly, the mean values of MSOT parameters were not different between PA and WT (all p > 0.05). Differences were seen for the maximal MSOT parameters. The maximal tumor values for 900 nm, HbR, HbT, and sO2 were lower in PA than in WT (all p < 0.05). This preliminary MSOT parotid tumor imaging study showed clear differences for PA or WT compared to healthy parotid tissue. Some MSOT characteristics of PA and WT were different but needed to be explored in larger studies.

Analysis of the Parotid Glands on an Energy Spectrum CT Iodine Map to Evaluate Irradiation-Induced Acute Xerostomia in Patients With Nasopharyngeal Carcinoma.

Objective: This prospective study aims to evaluate acute irradiation-induced xerostomia during radiotherapy by utilizing the normalized iodine concentration (NIC) derived from energy spectrum computed tomography (CT) iodine maps. Methods: In this prospective study, we evaluated 28 patients diagnosed with nasopharyngeal carcinoma. At 4 distinct stages of radiotherapy (0, 10, 20, and 30 fractions), each patient underwent CT scans to generate iodine maps. The NIC of both the left and right parotid glands was obtained, with the NIC at the 0-fraction stage serving as the baseline measurement. After statistically comparing the NIC obtained in the arterial phase, early venous phase, late venous phase, and delayed phase, we chose the late venous iodine concentration as the NIC and proceeded to analyze the variations in NIC at each radiotherapy interval. Using the series of NIC values, we conducted hypothesis tests to evaluate the extent of change in NIC within the parotid gland across different stages. Furthermore, we identified the specific time point at which the NIC decay exhibited the most statistically significant results. In addition, we evaluated the xerostomia grades of the patients at these 4 stages, following the radiation therapy oncology group (RTOG) xerostomia evaluation standard, to draw comparisons with the changes observed in NIC. Results: The NIC in the late venous phase exhibited the highest level of statistical significance (P < .001). There was a noticeable attenuation in NIC as the RTOG dry mouth grade increased. Particularly, at the 20 fraction, the NIC experienced the most substantial attenuation (P < .001), a significant negative correlation was observed between the NIC of the left, right, and both parotid glands, and the RTOG evaluation grade of acute irradiation-induced xerostomia (P < .001, r = -0.46; P < .001, r = -0.45; P < .001, r = -0.47). The critical NIC values for the left, right, and both parotid glands when acute xerostomia occurred were 0.175, 0.185, and 0.345 mg/ml, respectively, with AUC = 0.73, AUC = 0.75, and AUC = 0.75. Conclusion: The NIC may be used to evaluate changes in parotid gland function during radiotherapy and acute irradiation-induced xerostomia.

Lymphoma presenting as preauricular tumor in unilateral parotid gland agenesis: a case report and review of literature.

BACKGROUND: Parotid gland agenesis is a rare, congenital, usually asymptomatic disorder. Until now, only 24 cases with unilateral, incidentally found, parotid gland agenesis have been described. Here, we present the first reported case of an ipsilateral preauricular neoplasm in a patient with unilateral parotid gland agenesis. During surgery, the position of the greater auricular- and facial nerves was documented. Furthermore, we performed the first sialendoscopy for this rare disorder to assess the number of duct branches, which might be indicative of the abundance of parotid tissue. Moreover, we looked for sialendoscopic characteristic features that could aid in identifying these patients in the ambulatory setting. CASE PRESENTATION: A 50-year-old Greek man presented with a painless, slowly enlarging mass in the right parotid space. Magnetic resonance imaging revealed a complete absence of the right parotid gland without accessory parotid tissue. The right parotid gland was replaced by fatty tissue and the radiologist suggested a benign parotid tumor. Fine needle aspiration was indicative of a reactive lymph node. Sialendoscopy revealed only two branches within the right parotid duct. Surgical resection was performed through a conventional lateral parotidectomy. This revealed typical anatomic position of the greater auricular- and facial nerves despite the parotid tissue agenesis. Histopathology revealed a small lymphocytic lymphoma. CONCLUSIONS: Surgeons should feel confident to resect tumors of the parotid space in patients with parotid gland agenesis. Reduced branching observed during sialendoscopy might indicate parotid gland agenesis. Physicians should be even more cautious than usual with the watch and wait strategy in patients with tumors of parotid gland agenesis, since the probability of a tumor being a benign salivary gland tumor might be lower than usual.

Unicentric Castleman's disease in the parotid gland associated with psoriasis: a case report.

BACKGROUND: Castleman's disease is a rare lymphoproliferative disorder that is often misdiagnosed because of its untypical clinical or imaging features except for a painless mass. Besides, it is also difficult to cure Castleman's disease due to its unclear pathogenesis. CASE PRESENTATION: We present a Castleman's disease case with diagnostic significance regarding a 54-year-old Chinese male who has a painless mass in his left parotid gland for 18 months with a 30-years history of autoimmune disease psoriasis. Computed tomography scan showed a high-density nodule with clear boundaries in the left parotid and multiple enlarged lymph nodes in the left submandibular and neck region. General checkup, the extremely elevated serum interleukin-6 and lymph node biopsy in the left submandibular region gave us an initial suspicion of Castleman's disease. Then the patient underwent a left superficial parotidectomy. Based on histopathologic analysis, we made a certain diagnosis of Castleman's disease and gave corresponding treatments. In 18 months of follow-up, the patient showed no evidence of recurrence, with the level of serum interleukin-6 decreased. CONCLUSIONS: Clinicians should be aware of the possibility of Castleman's disease when faced with masses or enlarged lymph nodes in the parotid gland to avoid misdiagnosis, especially in patients with autoimmune diseases and elevated serum interleukin-6.

Metastasizing pleomorphic adenoma of the parotid gland: A common tumour with a very unusual presentation.

Metastasizing pleomorphic adenoma is recognized as a subtype of pleomorphic adenoma in WHO classification 5th edition of salivary glands. The controversy pertaining to the entity is the benign features of the disease even at a metastatic site. We present a rare case of left recurrent pre-auricular swelling in a young male reported as metastasizing pleomorphic adenoma. A nineteen-year-old male presented with left preauricular swelling seven years ago which was diagnosed as pleomorphic adenoma and underwent complete excision of tumour. The tumour recurred twice - two and five years after the surgery. At the second recurrence, the level II neck dissection showed multiple encapsulated deposits of pleomorphic adenoma having similar morphology in the cervical soft tissue with no features of high-grade transformation.

[Diffuse thickening of bronchial walls with multiple nodular mucosal protrusions].

A 58-year-old woman presented with a six-month history of nasal congestion, sore throat and cough, and a five-month history of dyspnea. She had a history of xerostomia for one year. On examination, the bilateral submandibular gland and parotid glands were enlarged. Parotid and anterior cervical lymph nodes were palpable. There were rales in both lungs. The rest of the physical examination was unremarkable. Sialographic analysis showed normal caliber in the main duct, stenosis in secondary ducts, and dilation in the proximal ducts. Minor salivary gland biopsy demonstrated periductal lymphocytic infiltration. Chest computed tomography (CT) showed diffuse thickening of the tracheal and bilateral bronchial walls. Bronchoscopy revealed macroscopic multiple nodules mainly in the trachea and bilateral main bronchus. Endobronchial biopsy showed lymphocytic infiltration in the bronchial submucosa. She was diagnosed with Sjögren's syndrome and treated with glucocorticoids. The dose of prednisone was started at 30 mg/d and tapered gradually. Following treatment, the patient's clinical condition improved dramatically, with shrinkage of the enlarged lymph nodes, bilateral submandibular and parotid glands. A repeated chest CT scan revealed improvement of the tracheal and bilateral bronchial thickening. Multiple nodules in the airway regressed, as evidenced by repeated bronchoscopic examination. The final diagnosis was a large-airway disease associated with Sjögren's syndrome.Among airway diseases in Sjögren's syndrome, peripheral airway diseases including bronchiolitis and bronchiectasis are common; however, central airway lesions in Sjögren's syndrome, especially with macroscopic nodules, are rare. In this case, we demonstrated tracheal and endobronchial nodules in Sjögren's syndrome as determined by clinical features, CT scan, bronchoscopy, and response to therapy.

Diagnostic Accuracy of Fine Needle Aspiration Cytology as Compared to Histopathology in Parotid Gland Swelling.

BACKGROUND: The diagnosis of parotid swelling is challenging and investigations like imaging and needle aspiration cytology are helpful. The objective of this study was to determine the diagnostic accuracy of fine needle aspiration cytology (FNAC) as compared to the histopathology in parotid gland swelling. METHODS: It was a descriptive cross sectional study carried out in the Department of ENT-Head and Neck Surgery, Tribhuvan University Teaching Hospital, Institute of Medicine, Kathmandu by reviewing the medical record charts of the patients who had undergone surgery for parotid lesions during the study period of seven and half years. All patients whose fine needle aspiration cytology and histopathology reports were available were included in the study. The data were presented as mean, standard deviation, ratio and percentages. Microsoft excel was used for data analysis. RESULTS: There were 75 patients included in the study. The age ranged from nine years to 78 years and the mean age being 38.3 17.42 years. The male to female ratio was 1:1.78. The concordance rate between fine needle aspiration cytology and histopathology was 82.7%. The sensitivity and specificity of the fine needle aspiration cytology were 80% and 95% respectively. Similarly, the positive predictive and negative predictive values were 84% and 93% respectively. The diagnostic accuracy of the fine needle aspiration cytology was 91% for the parotid swelling in our study. CONCLUSIONS: The diagnostic accuracy of fine needle aspiration cytology for parotid swellings in our study was excellent. The result of fine needle aspiration cytology is helpful in deciding management plan for parotid lesions.

Heterogeneous PSMA ligand uptake inside parotid glands.

The purpose of this investigation is to quantify the spatial heterogeneity of prostate-specific membrane antigen (PSMA) positron emission tomography (PET) uptake within parotid glands. We aim to quantify patterns in well-defined regions to facilitate further investigations. Furthermore, we investigate whether uptake is correlated with computed tomography (CT) texture features. METHODS: Parotid glands from [18F]DCFPyL PSMA PET/CT images of 30 prostate cancer patients were analyzed. Uptake patterns were assessed with various segmentation schemes. Spearman's rank correlation coefficient was calculated between PSMA PET uptake and feature values of a Grey Level Run Length Matrix using a long and short run length emphasis (GLRLML and GLRLMS) in subregions of the parotid gland. RESULTS: PSMA PET uptake was significantly higher (p < 0.001) in lateral/posterior regions of the glands than anterior/medial regions. Maximum uptake was found in the lateral half of parotid glands in 50 out of 60 glands. The difference in SUVmean between parotid halves is greatest when parotids are divided by a plane separating the anterior/medial and posterior/lateral halves symmetrically (out of 120 bisections tested). PSMA PET uptake was significantly correlated with CT GLRLML (p < 0.001), and anti-correlated with CT GLRLMS (p < 0.001). CONCLUSION: Uptake of PSMA PET is heterogeneous within parotid glands, with uptake biased towards lateral/posterior regions. Uptake within parotid glands was strongly correlated with CT texture feature maps.

Fenestration of the facial nerve by the stylomastoid artery.

BACKGROUND: Anatomic landmarks such as the tympanomastoid suture line, posterior belly of the digastric muscle, tragal pointer, and styloid process can assist the parotid surgeon in identifying and preserving the facial nerve. Vascular structures such as the posterior auricular artery and its branch, the stylomastoid artery, lay in close proximity to the facial nerve and have been proposed as landmarks for the identification of the facial nerve. In this case report, we describe an anatomic variation in which the stylomastoid artery has fenestrated the main trunk of the facial nerve, dividing it in two. METHODS: Two patients underwent parotidectomy (one for a pleomorphic adenoma, the second for a parotid cyst) through a standard anterograde approach with identification of the usual facial nerve landmarks. RESULTS: The appearance of the main trunk of the facial nerve was unusual in both patients due to its being fenestrated by the stylomastoid artery. The stylomastoid artery was divided, and the remainder of the facial nerve dissection was performed uneventfully with subsequent resection of the parotid mass in both patients. CONCLUSIONS: In rare instances, the stylomastoid artery can penetrate through the common trunk of the facial nerve. This is an important anatomic variant for the parotid surgeon to be aware of, as it can increase the difficulty of facial nerve dissection.

Clinical decision making when cytology indicates a Warthin tumor.

Warthin tumor (WT) is a benign tumor usually affecting the parotid gland. The main diagnostic tool remains ultrasound combined with fine-needle aspiration cytology (FNAC). This study aims to examine how reliably FNAC indicates WT for clinical decision making regarding surgical versus conservative management. We included all patients who underwent FNAC from a parotid gland lesion between 2016 and 2018 at our institution, and whose FNAC revealed WT suspicion. The FNACs were divided into three groups based on the cytology report: certain, likely, and possible WT. The patients were divided into two groups based on having had either surgery or follow-up. We sent a questionnaire to patients who had not undergone surgery in order to obtain follow-up for a minimum of four years. Altogether, 135 FNAC samples, from 133 tumors and 125 patients, showed signs of WT. Of the 125 patients, 44 (35%) underwent surgery, and 81 (65%) were managed conservatively. Preoperative misdiagnosis in FNAC occurred in three (7%) surgically treated tumors. Their FNACs were reported as possible WTs, but histopathology revealed another benign lesion. In the conservatively treated group, two patients underwent surgery later during the follow-up. Cytological statements of WT were seldom false, and none were malignant. The majority of the patients were only followed-up and rarely required further treatment. A certain or likely diagnosis of WT in the FNAC report by an experienced head and neck pathologist is highly reliable in selecting patients for conservative surveillance.

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.

Chinese surgical robot-assisted surgery for parotid tumor: a case report.

Robotic surgery is known as the "third technological revolution" in the field of surgery, and is an important milestone in the development of modern surgery. However, our country's innovative surgical robot industry is still in its early stages, and it is only being utilized in certain surgical fields. To explore the effectiveness of the application of domestic surgical robot in oral and maxillofacial surgery, the author successfully completed a case of benign parotid tumor resection with the assistance of a domestic autonomous robot. The operation was successful, facial nerve function was preserved, and postoperative wound healing was good.

Parotid hypersalivation after inferior salivatory nucleus glutamate/NMDA receptor excitation in the rat.

Although salivation is essential during eating behavior, little is known about the brainstem centers that directly control the salivary glands. With regard to the inferior salivatory nucleus (ISN), the site of origin of the parasympathetic preganglionic cell bodies that innervate the parotid glands, previous anatomical studies have located it within the rostrodorsal medullary reticular formation. However, to date there is no functional data that shows the secretory nature of the somas grouped in this region. To activate only the somas and rule out the activation of the efferent fibers from and the afferent fibers to the ISN, in exp. 1, NMDA neurotoxin was administered to the rostrodorsal medullary region and the secretion of saliva was recorded during the following hour. Results showed an increased secretion of parotid saliva but a total absence of submandibular-sublingual secretion. In exp. 2, results showed that the hypersecretion of parotid saliva after NMDA microinjection was completely blocked by the administration of atropine (a cholinergic blocker) but not after administration of dihydroergotamine plus propranolol (α and ß-adrenergic blockers, respectively). These findings suggest that the somata of the rostrodorsal medulla are secretory in nature, controlling parotid secretion via a cholinergic pathway. The data thus functionally supports the idea that these cells constitute the ISN.

Parotid Gland Cancer With First Bite Syndrome Detected via CT-Guided Fine Needle Aspiration Cytology.

BACKGROUND/AIM: First bite syndrome (FBS) is a symptom of severe pain at the beginning of a meal that lessens as the meal progresses. It is a common postoperative complication of parapharyngeal space tumors and is rarely reported as the first symptom of parotid carcinoma. The parapharyngeal space is considered a difficult area for approach; hence, preoperative histopathology is often challenging. However, there are hardly any reports on the approach of performing biopsies under computerized tomography (CT) guidance. CASE REPORT: A 28-year-old woman presented to our hospital with the chief complaint of pain in the left parotid region since the past year. Contrast-enhanced magnetic resonance imaging of the parotid gland revealed a 10-mm high-signal area on T2-weighted images extending from the deep lobe of the left parotid gland to the parapharyngeal space, which could not be visualized on ultrasound. She was suspected to have a malignant tumor because of the presence of a parotid tumor with FBS. Therefore, she underwent CT-guided fine-needle aspiration cytology (FNAC) and was diagnosed with adenoid cystic carcinoma. The patient underwent left parotid tumor resection and left cervical dissection, and her pain during feeding improved postoperatively. CONCLUSION: In a patient with parotid tumor extending into the parapharyngeal space with FBS as the initial symptom, CT-guided FNAC was successfully used to diagnose parotid carcinoma. Symptoms of pain, including FBS, should be considered in cases of malignancy. CT-guided FNAC is effective for lesions that cannot be visualized by ultrasound, such as those in the parapharyngeal space.

Characterization of parotid gland tumors using diffusion-relaxation correlation spectrum imaging: a preliminary study.

AIM: To assess the performance of diffusion-relaxation correlation spectrum imaging (DR-CSI) in the characterization of parotid gland tumors. MATERIALS AND METHODS: Twenty-five pleomorphic adenomas (PA) patients, 9 Warthin's tumors (WT) patients and 7 malignant tumors (MT) patients were prospectively recruited. DR-CSI (7 b-values combined with 5 TEs, totally 35 diffusion-weighted images) was scanned for pre-treatment assessment. Diffusion (D)-T2 signal spectrum summating all voxels were built for each patient, characterized by D-axis with range 0∼5 × 10-3 mm2/s, and T2-axis with range 0∼300ms. With boundaries of 0.5 and 2.5 × 10-3 mm2/s for D, all spectra were divided into three compartments labeled A (low D), B (mediate D) and C (high D). Volume fractions acquired from each compartment (VA, VB, VC) were compared among PA, WT and MT. Diagnostic performance was assessed using receiver operating characteristic analysis and area under the curve (AUC). RESULTS: Each subtype of parotid tumors had their specific D-T2 spectrum. PA showed significantly lower VA (8.85 ± 4.77% vs 20.68 ± 10.85%), higher VB (63.40 ± 8.18% vs 43.05 ± 7.16%), and lower VC (27.75 ± 8.51% vs 36.27 ± 11.09) than WT (all p<0.05). VB showed optimal diagnostic performance (AUC 0.969, sensitivity 92.00%, specificity 100.00%). MT showed significantly higher VA (21.23 ± 12.36%), lower VB (37.09 ± 6.43%), and higher VC (41.68 ± 13.72%) than PA (all p<0.05). Similarly, VB showed optimal diagnostic performance (AUC 0.994, sensitivity 96.00%, specificity 100.00%). No significant difference of VA, VB and VC was found between WT and MT. CONCLUSIONS: DR-CSI might be a promising and non-invasive way for characterizing parotid gland tumors.

Preoperative Direct Puncture Embolization of Castleman Disease of the Parotid Gland: A Case Report.

BACKGROUND: Castleman disease (CD) is an uncommon benign lymphoproliferative disease characterized by hypervascular lymphoid hyperplasia. We present a unique case of unicentric CD of the parotid gland treated by preoperative direct puncture embolization. CASE PRESENTATION: A 27-year-old female patient was admitted for a right neck mass. Ultrasound examination and MRI scan documented a hypervascular mass within the right parotid gland. Preoperative embolization was performed by direct puncture technique: a needle was inserted into the core of the mass under both ultrasound and fluoroscopic guidance and SQUID 12 was injected into the mass under fluoroscopic control, achieving a total devascularization. CONCLUSION: Preoperative direct puncture embolization was safe and effective and provides excellent hemostatic control during the surgical operation, limiting the amount of intraoperative bleeding.

Deep learning for the automatic detection and segmentation of parotid gland tumors on MRI.

OBJECTIVES: Parotid gland tumors (PGTs) often occur as incidental findings on magnetic resonance images (MRI) that may be overlooked. This study aimed to construct and validate a deep learning model to automatically identify parotid glands (PGs) with a PGT from normal PGs, and in those with a PGT to segment the tumor. MATERIALS AND METHODS: The nnUNet combined with a PG-specific post-processing procedure was used to develop the deep learning model trained on T1-weighed images (T1WI) in 311 patients (180 PGs with tumors and 442 normal PGs) and fat-suppressed (FS)-T2WI in 257 patients (125 PGs with tumors and 389 normal PGs), for detecting and segmenting PGTs with five-fold cross-validation. Additional validation set separated by time, comprising T1WI in 34 and FS-T2WI in 41 patients, was used to validate the model performance. RESULTS AND CONCLUSION: To identify PGs with tumors from normal PGs, using combined T1WI and FS-T2WI, the deep learning model achieved an accuracy, sensitivity and specificity of 98.2% (497/506), 100% (119/119) and 97.7% (378/387), respectively, in the cross-validation set and 98.5% (67/68), 100% (20/20) and 97.9% (47/48), respectively, in the validation set. For patients with PGTs, automatic segmentation of PGTs on T1WI and FS-T2WI achieved mean dice coefficients of 86.1% and 84.2%, respectively, in the cross-validation set, and of 85.9% and 81.0%, respectively, in the validation set. The proposed deep learning model may assist the detection and segmentation of PGTs and, by acting as a second pair of eyes, ensure that incidentally detected PGTs on MRI are not missed.

Direct visualization of intraparotid facial nerve assisting in parotid tumor resection.

Precise recognition of the intraparotid facial nerve (IFN) is crucial during parotid tumor resection. We aimed to explore the application effect of direct visualization of the IFN in parotid tumor resection. Fifteen patients with parotid tumors were enrolled in this study and underwent specific radiological scanning in which the IFNs were displayed as high-intensity images. After image segmentation, IFN could be preoperatively directly visualized. Mixed reality combined with surgical navigation were applied to intraoperatively directly visualize the segmentation results as real-time three-dimensional holograms, guiding the surgeons in IFN dissection and tumor resection. Radiological visibility of the IFN, accuracy of image segmentation and postoperative facial nerve function were analyzed. The trunks of IFN were directly visible in radiological images for all patients. Of 37 landmark points on the IFN, 36 were accurately segmented. Four patients were classified as House-Brackmann Grade I postoperatively. Two patients with malignancies had postoperative long-standing facial paralysis. Direct visualization of IFN was a feasible novel method with high accuracy that could assist in recognition of IFN and therefore potentially improve the treatment outcome of parotid tumor resection.