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: Evaluation of alveolar bone is important in the diagnosis of dental diseases. The periodontal ligament space is difficult to clearly depict in cone-beam computed tomography images because the reconstruction filter conditions during image processing cause image blurring, resulting in decreased spatial resolution. We examined different reconstruction filters to assess their ability to improve spatial resolution and allow for a clearer visualization of the periodontal ligament space. MATERIALS AND METHODS: Cone-beam computed tomography projections of 2 skull phantoms were reconstructed using 6 reconstruction conditions and then compared using the Thurstone paired comparison method. Physical evaluations, including the modulation transfer function and the Wiener spectrum, as well as an assessment of space visibility, were undertaken using experimental phantoms. RESULTS: Image reconstruction using a modified Shepp-Logan filter resulted in better sensory, physical, and quantitative evaluations. The reconstruction conditions substantially improved the spatial resolution and visualization of the periodontal ligament space. The difference in sensitivity was obtained by altering the reconstruction filter. CONCLUSION: Modifying the characteristics of a reconstruction filter can generate significant improvement in assessments of the periodontal ligament space. A high-frequency enhancement filter improves the visualization of thin structures and will be useful when accurate assessment of the periodontal ligament space is necessary.
Cone-Beam Computed Tomography* ; Diagnosis ; Evaluation Studies as Topic ; Image Processing, Computer-Assisted ; In Vitro Techniques* ; Matched-Pair Analysis ; Methods ; Periodontal Ligament* ; Phantoms, Imaging ; Skull ; Stomatognathic Diseases

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.