Adult parotitis exhibits various appearances on images. The purpose of this study was to investigate the imaging features of adult parotitis, focusing on the inflammatory spread in and around the parotid gland on CT images. We investigated 21 patients who were clinically and radiologically diagnosed with parotitis, including patients with concomitant occurrences of sialolith or Sjören's syndrome. Intra-glandular spread was divided into 13 diffuse types and 8 focal types. There was a significant difference in duration from the first onset of symptoms between the diffuse and focal types. Six of 8 patients showing focal type spread were associated with the concomitant occurrence of sialolith or Sjören's syndrome. Extra-glandular spread was observed in 13 (62%) patients. Of them, 12 (92%) showed subcutaneous fat tissue and/or masticator space involvement. Involvement of the parapharyngeal space and the superficial area just below the gland was observed in 4 and 7 patients, respectively. The appearance of extra-glandular spread was influenced by intra-glandular appearance and concomitant disease. The spread of adult parotitis possessed characteristic features in relation to clinical findings and concomitant disease. CT examination appeared to be effective for these diagnoses.

Ultrasonography may provide some information as to the tissue characteristics of tumorous lesions in the floor of the mouth, which have not been sufficiently clarified. Ultrasonographic imaging characteristics of these lesions are presented and the differential diagnoses are discussed. Ultrasonographic images of 5 patients with metastatic lingual lymph nodes (squamous cell carcinoma), lymphangioma, Schwannoma, ranula and dermoid cyst are presented. The literature on the imaging features of tumorous lesions in the floor of the mouth was searched using Medline. Five cases of tumorous lesions in the floor of the mouth are presented. The differential diagnosis through a review of the references was discussed. Ultrasonographic images clearly showed the internal structures of the mass. The homogeneity varied according to the degree of closeness of the cells and tissues, or the presence of fluid, hemorrhage, cystic degeneration and calculus. The echogenicity was due to the high acoustic impedance of calculus, cholesterol, and so on. The imaging features varied according to the ratio of the tissues, such as fat and fibrous tissue (in lipoma), or cholesterol and keratin (in dermoid cyst). A high vascular mass indicated malignant salivary gland tumors and hemangioma. In conclusion, ultrasonographic images revealed the distinctive features of the lesions and were useful for the differential diagnosis. Therefore, ultrasonography could be used to conjecture the content of the lesions and is considered to be useful for easy and accurate diagnosis prior to treatment.

Purpose: The aims of this study were to create a deep learning model to distinguish between nasopalatine duct cysts (NDCs), radicular cysts, and no-lesions (normal) in the midline region of the anterior maxilla on panoramic radiographs and to compare its performance with that of dental residents. Materials and Methods: One hundred patients with a confirmed diagnosis of NDC (53 men, 47 women; average age, 44.6±16.5 years), 100 with radicular cysts (49 men, 51 women; average age, 47.5±16.4 years), and 100 with normal groups (56 men, 44 women; average age, 34.4±14.6 years) were enrolled in this study. Cases were randomly assigned to the training datasets (80%) and the test dataset (20%). Then, 20% of the training data were randomly assigned as validation data. A learning model was created using a customized DetectNet built in Digits version 5.0 (NVIDIA, Santa Clara, USA). The performance of the deep learning system was assessed and compared with that of two dental residents. Results: The performance of the deep learning system was superior to that of the dental residents except for the recall of radicular cysts. The areas under the curve (AUCs) for NDCs and radicular cysts in the deep learning system were significantly higher than those of the dental residents. The results for the dental residents revealed a significant difference in AUC between NDCs and normal groups. Conclusion This study showed superior performance in detecting NDCs and radicular cysts and in distinguishing between these lesions and normal groups.

Purpose: The aim of this study was to clarify the influence of training with a different kind of lesion on the performance of a target model. Materials and Methods: A total of 310 patients (211 men, 99 women; average age, 47.9±16.1 years) were selected and their panoramic images were used in this study. We created a source model using panoramic radiographs including mandibular radiolucent cyst-like lesions (radicular cyst, dentigerous cyst, odontogenic keratocyst, and ameloblastoma). The model was simulatively transferred and trained on images of Stafne’s bone cavity. A learning model was created using a customized DetectNet built in the Digits version 5.0 (NVIDIA, Santa Clara, CA). Two machines (Machines A and B) with identical specifications were used to simulate transfer learning. A source model was created from the data consisting of ameloblastoma, odontogenic keratocyst, dentigerous cyst, and radicular cyst in Machine A. Thereafter, it was transferred to Machine B and trained on additional data of Stafne’s bone cavity to create target models. To investigate the effect of the number of cases, we created several target models with different numbers of Stafne’s bone cavity cases. Results: When the Stafne’s bone cavity data were added to the training, both the detection and classification performances for this pathology improved. Even for lesions other than Stafne’s bone cavity, the detection sensitivities tended to increase with the increase in the number of Stafne’s bone cavities. Conclusion This study showed that using different lesions for transfer learning improves the performance of the model.

Purpose: This study investigated the effects of 1 year of training on imaging diagnosis, using static ultrasonography (US) salivary gland images of Sjögren syndrome patients. Materials and Methods: This study involved 3 inexperienced radiologists with different levels of experience, who received training 1 or 2 days a week under the supervision of experienced radiologists. The training program included collecting patient histories and performing physical and imaging examinations for various maxillofacial diseases. The 3 radiologists (observers A, B, and C) evaluated 400 static US images of salivary glands twice at a 1-year interval. To compare their performance, 2 experienced radiologists evaluated the same images. Diagnostic performance was compared between the 2 evaluations using the area under the receiver operating characteristic curve (AUC). Results: Observer A, who was participating in the training program for the second year, exhibited no significant difference in AUC between the first and second evaluations, with results consistently comparable to those of experienced radiologists. After 1 year of training, observer B showed significantly higher AUCs than before training. The diagnostic performance of observer B reached the level of experienced radiologists for parotid gland assessment, but differed for submandibular gland assessment. For observer C, who did not complete the training, there was no significant difference in the AUC between the first and second evaluations, both of which showed significant differences from those of the experienced radiologists. Conclusion These preliminary results suggest that the training program effectively helped inexperienced radiologists reach the level of experienced radiologists for US examinations.

Purpose: The purpose of this study was to clarify the panoramic image differences of cleft alveolus patients with or without a cleft palate, with emphases on the visibility of the line formed by the junction between the nasal septum and nasal floor (the upper line) and the appearances of the maxillary lateral incisor. Materials and Methods: Panoramic radiographs of 238 patients with cleft alveolus were analyzed for the visibility of the upper line, including clear, obscure or invisible, and the appearances of the maxillary lateral incisor, regarding congenital absence, incomplete growth, delayed eruption and medial inclination. Differences in the distribution ratio of these visibility and appearances were verified between the patients with and without a cleft palate using the chi-square test. Results: There was a significant difference in the visibility distribution of the upper line between the patients with and without a cleft palate (p<0.05). In most of the patients with a cleft palate, the upper line was not observed. In the unilateral cleft alveolus patients, the medial inclination of the maxillary lateral incisor was more frequently observed in patients with a cleft palate than in patients without a cleft palate. Conclusion Two differences were identified in panoramic appearances. The first was the disappearance (invisible appearance) of the upper line in patients with a cleft palate, and the second was a change in the medial inclination on the affected side maxillary lateral incisor in unilateral cleft alveolus patients with a cleft palate.

Mandibular chronic osteomyelitis with diffuse osteosclerosis is recognized as an intractable infectious disease. We emplyed decortication and intra-arterial infusion of antibiotics in 6 cases. Decortication on the affected mandible was performed with retrocatherization to the superficial temporal artery of affected side under general anesthesia. Antibiotics, IPM/CS or FOMX was used through the artery for 4-11 days. In addition, we administered FOMX, PIPC intravenously for 8-17 days. CT and MRI were taken postoperatively. The postoperative follow-up period ranged from 1 year and 6 months to 2 years and 5 months. Postoperative MR showed that bone marrow signal was recovered to approximately normal in 4 cases. High signal area of bone marrow and osteosclerosis image remained in 2 cases, but showed improvement. The results were satisfactory without recurrence in all of 6 cases.
Anesthesia, General ; Anti-Bacterial Agents ; Arteries ; Bone Marrow ; Communicable Diseases ; Follow-Up Studies ; Infusions, Intra-Arterial ; Mandible ; Osteomyelitis ; Osteosclerosis ; Recurrence ; Temporal Arteries

Purpose: This study aimed to assess the performance of 2-dimensional (2D) imaging with microscopy coils in delineating teeth and periodontal tissues compared with conventional 3-dimensional (3D) imaging on a 3 T magnetic resonance imaging (MRI) unit. Materials and Methods: Twelve healthy participants (4 men and 8 women; mean age: 25.6 years; range: 20-52years) with no dental symptoms were included. The left mandibular first molars and surrounding periodontal tissueswere examined using the following 2 sequences: 2D proton density-weighted (PDw) images and 3D enhanced T1 high-resolution isotropic volume excitation (eTHRIVE) images. Two-dimensional MRI images were taken using a 3 T MRI unit and a 47 mm microscopy coil, while 3D MRI imaging used a 3 T MRI unit and head-neck coil.Oral radiologists assessed dental and periodontal structures using a 4-point Likert scale. Inter- and intra-observer agreement was determined using the weighted kappa coefficient. The Wilcoxon signed-rank test was used to compare 2D-PDw and 3D-eTHRIVE images. Results: Qualitative analysis showed significantly better visualization scores for 2D-PDw imaging than for 3D-eTHRIVE imaging (Wilcoxon signed-rank test). 2D-PDw images provided improved visibility of the tooth, root dental pulp, periodontal ligament, lamina dura, coronal dental pulp, gingiva, and nutrient tract. Inter-observer reliability ranged from moderate agreement to almost perfect agreement, and intra-observer agreement was in a similar range. Conclusion Two-dimensional-PDw images acquired using a 3 T MRI unit and microscopy coil effectively visualized nearly all aspects of teeth and periodontal tissues.

Purpose: This study aimed to assess the performance of 2-dimensional (2D) imaging with microscopy coils in delineating teeth and periodontal tissues compared with conventional 3-dimensional (3D) imaging on a 3 T magnetic resonance imaging (MRI) unit. Materials and Methods: Twelve healthy participants (4 men and 8 women; mean age: 25.6 years; range: 20-52years) with no dental symptoms were included. The left mandibular first molars and surrounding periodontal tissueswere examined using the following 2 sequences: 2D proton density-weighted (PDw) images and 3D enhanced T1 high-resolution isotropic volume excitation (eTHRIVE) images. Two-dimensional MRI images were taken using a 3 T MRI unit and a 47 mm microscopy coil, while 3D MRI imaging used a 3 T MRI unit and head-neck coil.Oral radiologists assessed dental and periodontal structures using a 4-point Likert scale. Inter- and intra-observer agreement was determined using the weighted kappa coefficient. The Wilcoxon signed-rank test was used to compare 2D-PDw and 3D-eTHRIVE images. Results: Qualitative analysis showed significantly better visualization scores for 2D-PDw imaging than for 3D-eTHRIVE imaging (Wilcoxon signed-rank test). 2D-PDw images provided improved visibility of the tooth, root dental pulp, periodontal ligament, lamina dura, coronal dental pulp, gingiva, and nutrient tract. Inter-observer reliability ranged from moderate agreement to almost perfect agreement, and intra-observer agreement was in a similar range. Conclusion Two-dimensional-PDw images acquired using a 3 T MRI unit and microscopy coil effectively visualized nearly all aspects of teeth and periodontal tissues.

Purpose: This study aimed to assess the performance of 2-dimensional (2D) imaging with microscopy coils in delineating teeth and periodontal tissues compared with conventional 3-dimensional (3D) imaging on a 3 T magnetic resonance imaging (MRI) unit. Materials and Methods: Twelve healthy participants (4 men and 8 women; mean age: 25.6 years; range: 20-52years) with no dental symptoms were included. The left mandibular first molars and surrounding periodontal tissueswere examined using the following 2 sequences: 2D proton density-weighted (PDw) images and 3D enhanced T1 high-resolution isotropic volume excitation (eTHRIVE) images. Two-dimensional MRI images were taken using a 3 T MRI unit and a 47 mm microscopy coil, while 3D MRI imaging used a 3 T MRI unit and head-neck coil.Oral radiologists assessed dental and periodontal structures using a 4-point Likert scale. Inter- and intra-observer agreement was determined using the weighted kappa coefficient. The Wilcoxon signed-rank test was used to compare 2D-PDw and 3D-eTHRIVE images. Results: Qualitative analysis showed significantly better visualization scores for 2D-PDw imaging than for 3D-eTHRIVE imaging (Wilcoxon signed-rank test). 2D-PDw images provided improved visibility of the tooth, root dental pulp, periodontal ligament, lamina dura, coronal dental pulp, gingiva, and nutrient tract. Inter-observer reliability ranged from moderate agreement to almost perfect agreement, and intra-observer agreement was in a similar range. Conclusion Two-dimensional-PDw images acquired using a 3 T MRI unit and microscopy coil effectively visualized nearly all aspects of teeth and periodontal tissues.