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Objective Both clinical and X-ray findings have been used for postoperative assessment of the donor site following secondary alveolar bone grafting in our department. However, this approach requires that patients be exposed to X-ray irradiation several times at the donor site and the cleft site. Furthermore, the findings do not depict bone healing status in detail and thus offer little information to help in deciding the required duration of postoperative movement restriction. Therefore, we sought to determine the utility of ultrasound in addition to X-ray for evaluating bone surface healing at the donor site. Methods Subjects were 17 patients (9 boys and 8 girls; median weight of harvested bone, 7.5 g) who underwent alveolar bone grafting using tibial grafts. All cases were evaluated on X-ray and ultrasound images. Results Agreement between the X-ray and ultrasound assessments was 88.2 % (15/17) at postoperative month 3 and 70.6 % (12/17) at postoperative month 6. No significant differences were observed, but the time required for healing tended to be longer when the weight of harvested bone was larger. Conclusions Ultrasound was a useful modality in postoperative assessment, and the combined use of ultrasound and X-ray examination was found to enable reduced exposure to X-ray irradiation and close observation of the bone surface. Also, movement restriction of ≥1 month appeared necessary, and the time to healing was longer for a larger weight of harvested bone.

Objectives: The purpose of this study was to evaluate the difference in performance of deep-learning (DL) models with respect to the image classes and amount of training data to create an effective DL model for detecting both unilateral cleft alveoli (UCAs) and bilateral cleft alveoli (BCAs) on panoramic radiographs. Methods: Model U was created using UCA and normal images, and Model B was created using BCA and normal images. Models C1 and C2 were created using the combined data of UCA, BCA, and normal images. The same number of CAs was used for training Models U, B, and C1, whereas Model C2 was created with a larger amount of data. The performance of all four models was evaluated with the same test data and compared with those of two human observers. Results: The recall values were 0.60, 0.73, 0.80, and 0.88 for Models A, B, C1, and C2, respectively. The results of Model C2 were highest in precision and F-measure (0.98 and 0.92) and almost the same as those of human observers. Significant differences were found in the ratios of detected to undetected CAs of Models U and C1 (p = 0.01), Models U and C2 (p < 0.001), and Models B and C2 (p = 0.036). Conclusions: The DL models trained using both UCA and BCA data (Models C1 and C2) achieved high detection performance. Moreover, the performance of a DL model may depend on the amount of training data.

Objectives: The aims of the present study were to construct a deep learning model for automatic segmentation of the temporomandibular joint (TMJ) disc on magnetic resonance (MR) images, and to evaluate the performances using the internal and external test data. Methods: In total, 1200 MR images of closed and open mouth positions in patients with temporomandibular disorder (TMD) were collected from two hospitals (Hospitals A and B). The training and validation data comprised 1000 images from Hospital A, which were used to create a segmentation model. The performance was evaluated using 200 images from Hospital A (internal validity test) and 200 images from Hospital B (external validity test). Results: Although the analysis of performance determined with data from Hospital B showed low recall (sensitivity), compared with the performance determined with data from Hospital A, both performances were above 80%. Precision (positive predictive value) was lower when test data from Hospital A were used for the position of anterior disc displacement. According to the intra-articular TMD classification, the proportions of accurately assigned TMJs were higher when using images from Hospital A than when using images from Hospital B. Conclusion: The segmentation deep learning model created in this study may be useful for identifying disc positions on MR images.

Objective: The present study aimed to verify the classification performance of deep learning (DL) models for diagnosing fractures of the mandibular condyle on panoramic radiographs using data sets from two hospitals and to compare their internal and external validities. Methods: Panoramic radiographs of 100 condyles with and without fractures were collected from two hospitals and a fivefold cross-validation method was employed to construct and evaluate the DL models. The internal and external validities of classification performance were evaluated as accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC). Results: For internal validity, high classification performance was obtained, with AUC values of >0.85. Conversely, external validity for the data sets from the two hospitals exhibited low performance. Using combined data sets from both hospitals, the DL model exhibited high performance, which was slightly superior or equal to that of the internal validity but without a statistically significant difference. Conclusion: The constructed DL model can be clinically employed for diagnosing fractures of the mandibular condyle using panoramic radiographs. However, the domain shift phenomenon should be considered when generalizing DL systems.

Objective: The first aim of this study was to determine the performance of a deep learning object detection technique in the detection of maxillary sinuses on panoramic radiographs. The second aim was to clarify the performance in the classification of maxillary sinus lesions compared with healthy maxillary sinuses. Methods: The imaging data for healthy maxillary sinuses (587 sinuses, Class 0), inflamed maxillary sinuses (416 sinuses, Class 1), cysts of maxillary sinus regions (171 sinuses, Class 2) were assigned to training, testing 1, and testing 2 data sets. A learning process of 1000 epochs with the training images and labels was performed using DetectNet, and a learning model was created. The testing 1 and testing 2 images were applied to the model, and the detection sensitivities and the false-positive rates per image were calculated. The accuracies, sensitivities and specificities were determined for distinguishing the inflammation group (Class 1) and cyst group (Class 2) with respect to the healthy group (Class 0). Results: Detection sensitivities of healthy (Class 0) and inflamed (Class 1) maxillary sinuses were 100% for both testing 1 and testing 2 data sets, whereas they were 98 and 89% for cysts of the maxillary sinus regions (Class 2). False-positive rates per image were nearly 0.00. Accuracies, sensitivities and specificities for diagnosis maxillary sinusitis were 90–91%, 88–85%, and 91–96%, respectively; for cysts of the maxillary sinus regions, these values were 97–100%, 80–100%, and 100–100%, respectively. Conclusion: Deep learning could reliably detect the maxillary sinuses and identify maxillary sinusitis and cysts of the maxillary sinus regions. Advances in knowledge: This study using a deep leaning object detection technique indicated that the detection sensitivities of maxillary sinuses were high and the performance of maxillary sinus lesion identification was ≧80%. In particular, performance of sinusitis identification was ≧90%.

Age-related EBV-associated B-cell lymphoproliferative disorders (AEBVLPD) was incorporated into the 2008 World Health Organization classification of lymphomas as Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma of the elderly. This disease is defined as a histologically malignant polymorphic or monomorphic B-cell lymphoproliferation in patients more than 50 years of age without any known immunodeficiency or prior lymphoma. These patients have been reported to have a worse prognosis than those with EBV-negative diffuse large B-cell lymphoma or EBV-positive Hodgkin lymphoma. Here we describe a case of age-related EBV-associated B-cell lymphoproliferative disorder arising in the minor salivary gland, which is a disease that has rarely been reported in the oral and maxillofacial regions. This case report is on a patient who also had a history of remitting seronegative symmetrical synovitis with pitting edema syndrome and had been administrated low-dose prednisolone.

The purpose of this study was to investigate regional brain activity during jaw clenching with natural teeth and with two types of occlusal splints using functional magnetic resonance imaging (fMRI).Sixteen healthy volunteers were enrolled in this study. Blood oxygenation level-dependent (BOLD) fMRI signals were compared under three conditions: during clenching with natural teeth, with a soft splint, and with a hard splint. For each condition, 30-second jaw clenching followed a 60-second rest, and was repeated three times, with intervening 30-second rests. SPM 8 was used for the fMRI analysis.Blood oxygenation level-dependent signals during clenching with natural teeth increased in BA44, 45, and the cerebellum. Blood oxygenation level-dependent signals increased in those areas and in BA17, 18 during clenching with a soft splint. Use of the hard splint increased the BOLD signals in BA6 and BA20, 37 in addition to the areas previously mentioned. Blood oxygenation level-dependent signals in the left BA6, the left BA20, 37, and the right BA44, 45 were significantly higher during clenching with a hard splint than with natural teeth. These regions are associated with motor coordination, memory, and cognition, respectively.Jaw clenching with a hard splint caused activity in the widest brain regions, including the associated area with motor coordination.

Objectives: We evaluated the diagnostic performance of a deep learning system for the detection of Sjögren’s syndrome (SjS) in ultrasonography (US) images, and compared it with the performance of inexperienced radiologists. Methods: 100 patients with a confirmed diagnosis of SjS according to both the Japanese criteria and American-European Consensus Group criteria and 100 non-SjS patients that had a dry mouth and suspected SjS but were definitively diagnosed as non-SjS were enrolled in this study. All the patients underwent US scans of both the parotid glands (PG) and submandibular glands (SMG). The training group consisted of 80 SjS patients and 80 non-SjS patients, whereas the test group consisted of 20 SjS patients and 20 non-SjS patients for deep learning analysis. The performance of the deep learning system for diagnosing SjS from the US images was compared with the diagnoses made by three inexperienced radiologists. Results: The accuracy, sensitivity and specificity of the deep learning system for the PG were 89.5, 90.0 and 89.0%, respectively, and those for the inexperienced radiologists were 76.7, 67.0 and 86.3%, respectively. The deep learning system results for the SMG were 84.0, 81.0 and 87.0%, respectively, and those for the inexperienced radiologists were 72.0, 78.0 and 66.0%, respectively. The AUC for the inexperienced radiologists was significantly different from that of the deep learning system. Conclusions: The deep learning system had a high diagnostic ability for SjS. This suggests that deep learning could be used for diagnostic support when interpreting US images.

Objectives: This study estimated the diagnostic performance of a deep learning system for detection of Sjögren's syndrome (SjS) on CT, and compared it with the performance of radiologists. Methods: CT images were assessed from 25 patients confirmed to have SjS based on the both Japanese criteria and American-European Consensus Group criteria and 25 control subjects with no parotid gland abnormalities who were examined for other diseases. 10 CT slices were obtained for each patient. From among the total of 500 CT images, 400 images (200 from 20 SjS patients and 200 from 20 control subjects) were employed as the training data set and 100 images (50 from 5 SjS patients and 50 from 5 control subjects) were used as the test data set. The performance of a deep learning system for diagnosing SjS from the CT images was compared with the diagnoses made by six radiologists (three experienced and three inexperienced radiologists). Results: The accuracy, sensitivity, and specificity of the deep learning system were 96.0%, 100% and 92.0%, respectively. The corresponding values of experienced radiologists were 98.3%, 99.3% and 97.3% being equivalent to the deep learning, while those of inexperienced radiologists were 83.5%, 77.9% and 89.2%. The area under the curve of inexperienced radiologists were significantly different from those of the deep learning system and the experienced radiologists. Conclusions: The deep learning system showed a high diagnostic performance for SjS, suggesting that it could possibly be used for diagnostic support when interpreting CT images.

OBJECTIVES: The distal root of the mandibular first molar occasionally has an extra root, which can directly affect the outcome of endodontic therapy. In this study, we examined the diagnostic performance of a deep learning system for classification of the root morphology of mandibular first molars on panoramic radiographs. Dental cone-beam CT (CBCT) was used as the gold standard. METHODS: CBCT images and panoramic radiographs of 760 mandibular first molars from 400 patients who had not undergone root canal treatments were analyzed. Distal roots were examined on CBCT images to determine the presence of a single or extra root. Image patches of the roots were segmented from panoramic radiographs and applied to a deep learning system, and its diagnostic performance in the classification of root morphplogy was examined. RESULTS: Extra roots were observed in 21.4% of distal roots on CBCT images. The deep learning system had diagnostic accuracy of 86.9% for the determination of whether distal roots were single or had extra roots. CONCLUSIONS: The deep learning system showed high accuracy in the differential diagnosis of a single or extra root in the distal roots of mandibular first molars.

Purpose The purpose of this study was to investigate computed tomography (CT) and clinical features relating to calcifications within the parotid gland of patients with Sjogren's syndrome (SS). Methods Data from 30 patients with SS who had been examined by CT were extracted from our radiological information database accumulated from 2001 to 2011, and their CT images were reread carefully. Of these patients, 14 (all female; age range 20–95years; mean age 61.4years) with calcifications within the parotid gland were retrospectively investigated with CT findings. The relationship between calcification occurrence and clinical symptoms including parotid swelling and/or saliva colic was investigated. The degree of destruction of the parotid gland on CT images was also evaluated. Results All calcifications of 14 patients were located within the parotid gland, not in the parotid duct. CT images of all calcifications showed small and regular round shapes. Multiple occurrences of calcifications were recognized in 10 patients, and a solitary occurrence was seen in 4 patients. Seven patients had bilateral calcifications. There was little relationship between the occurrence of calcifications and clinical symptoms, and the severity of destruction of the parotid gland. Conclusion The presented CT and clinical features would be peculiar to SS because too many patients lacked the typical features of sialoliths within the parotid gland.

Objective The aim of this study was to clarify the sonographic features of the masseter muscle as indices for judging the efficacy of massage treatment. Study design Fifteen patients with temporomandibular disorder (10 with unilateral and 5 with bilateral muscle pain) underwent massage treatment alternately on the bilateral masseter and temporal muscles with an oral rehabilitation robot. Sonography was performed before and after treatment, and the masseter thickness and existence of anechoic areas were evaluated. Results The thickness on the symptomatic side in the unilateral group significantly decreased after treatment. Anechoic areas were shown in 20 muscles (66.7%) before treatment, and disappeared or were reduced in size in 17 muscles (85.0%) after treatment. The pretreatment thickness was significantly related to visual analog scale (VAS) scores regarding posttreatment muscle pain and massage impression. The existence of anechoic areas was relevant to VAS scores regarding muscle pain. Conclusion Masseter thickness and existence of anechoic areas might be related to the therapeutic efficacy regarding muscle pain.

To investigate the safety, suitable treatment regimen, and efficacy of masseter and temporal muscle massage treatment using an oral rehabilitation robot.Forty-one temporomandibular disorder (TMD) patients with myofascial pain (8 men, 33 women, median age: 46 years) were enrolled. The safety, suitable massage regimen, and efficacy of this treatment were investigated. Changes in masseter muscle thickness were evaluated on sonograms.No adverse events occurred with any of the treatment sessions. Suitable massage was at pressure of 10 N for 16 minutes. Five sessions were performed every 2 weeks. Total duration of treatment was 9·5 weeks in median. Massage treatment was effective in 70·3% of patients. Masseter muscle thickness decreased with treatment in the therapy-effective group.This study confirmed the safety of massage treatment, and established a suitable regimen. Massage was effective in 70·3% of patients and appeared to have a potential as one of the effective treatments for myofascial pain.

Objective The aims of this study were to characterize the symmetrical features of patients with facial deformities and to suggest a classification system for facial asymmetry based on 3-dimensional-computed tomography (3D-CT) evaluation. Study design Preoperative CT images were investigated for 49 patients with maxillofacial deformities. Asymmetry indices were calculated for some landmarks in the maxilla, mandibular body and the mandibular ramus regions. Results Asymmetry was observed most frequently in the mandibular body region. The subjects were divided into 3 groups. Subjects without any asymmetry in the 3 regions were classified as Group I (44.9%). Groups II or III were defined for subjects without or with maxillary region asymmetry, respectively, and they were subcategorized. In Group IIA (8.2%), asymmetry was shown solely in the mandibular body region, and in Group IIB (18.4%), additional asymmetry was shown in the mandibular ramus region. Group IIIA (6.1%) showed asymmetry only in the maxillary region, and Group IIIB (22.4%) showed asymmetry in all 3 regions. Conclusion The 3D-CT classification for facial asymmetry has the potential to replace the conventional cephalometric classification.

Purpose Condylar remodeling, which develops after mandibular setback osteotomy, was evaluated and compared in CT, plain film radiographs, and MR images acquired postoperatively. Methods Thirty-nine patients treated with sagittal split ramus osteotomy (SSRO) and 46 patients treated with intraoral vertical ramus osteotomy (IVRO) were studied. Remodeling as seen in the images and the diagnostic agreement between imaging modalities was evaluated. Results A newly formed bone layer in the posterior part of the condylar head was identified as a sign suggestive of remodeling. This sign was seen predominantly at periods over 6 months postoperatively. IVRO subjects had a higher incidence of remodeling than did the SSRO group. The diagnostic agreement between the 3 imaging modalities was substantial. There was a positive correlation between postoperative condylar displacement and the incidence of remodeling. Conclusions The incidence of postoperative condylar head remodeling may be predictable. High-dose postoperative imaging studies to assess the TMJ should be restricted to those cases having a clear need for such studies.

Objectives The aims of the present study were to clarify the anatomy of impacted mandibular third molars in relation to surrounding structures and to investigate the pathway of infection originating from pericoronitis of this tooth. Study design Computed tomography (CT) images were evaluated in 87 patients with uninfected mandibular third molar impaction and in 12 patients with infection originating from an impacted mandibular third molar. In uninfected patients, bony features around the impacted crown were investigated together with the relationship between the crown and surrounding muscles. In infected patients, involvements of bony and soft tissue structures were evaluated according to the disappearance of cortices and lateral asymmetry of density and shape in the spaces and muscles. Results In uninfected patients, the disappearance of the lingual cortical plate was observed in 48 (35.3%) impacted molars, while only in 11 (8.1%) teeth for buccal cortices. The cortical thickness was thinner on the lingual side than the buccal side. Sixty-five percent of the masseter muscle horizontally overlapped the crown, while almost all of the medial pterygoid muscle was posteriorly situated apart from the crown. The mylohyoid muscle horizontally overlapped the crown at below or intermediate vertical positions. In infected patients, the involvement of lingual structures was more frequently observed than that of buccal structures. The mylohyoid muscle was involved in 10 (83.3%) of 12 patients. Among them, 8 showed submandibular space involvement. Conclusion CT findings supported the clinical observations of infection spread in patients with pericoronitis of the impacted mandibular third molar. CT appeared to be an effective tool for investigating the pathway of infection originating from the pericoronitis of impacted mandibular third molars.

Objective The purpose of the present study was to examine ultrasonographic appearances in female patients with temporomandibular disorder (TMD) associated with myofascial pain in comparison with healthy volunteers. Study design The thickness of the masseter muscle in 25 female patients with TMD was measured at rest and at maximum contraction using ultrasonography. The visibility and width of the internal echogenic bands of the masseter muscle were also assessed and the muscle appearance was classified as 1 of 3 types: type I, characterized by the clear visibility of the fine bands; type II, thickening and weakened echo-intensity of the bands; type III, disappearance or reduction in number of the bands. Results There were significant differences in the thickness at rest and the increase ratio by contraction between the patient and control groups. The distribution of muscle types showed a significant difference between the 2 groups. Conclusion The ultrasonographic features of the masseter muscle in TMD patients with myofascial pain were clarified and they might be related to muscle edema.

Adenoid cystic carcinoma (ACC) is known for its slow-growing but severely infiltrative nature with little tissue reaction. Although the masticatory muscles are often involved, their imaging features have not been well elucidated. We hereby report three patients with widespread ACC, which initially appeared with trismus and/or temporomandibular symptoms and involved the masticator space. Possible features of masticator space involvement are presented on magnetic resonance (MR) images. Masticatory muscle changes on MR images consisted of two aspects, namely, denervation changes and direct tumour invasion.

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 Sjogren'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 Sjogren's syndrome. Extra-glandular spread was observed in 13 (6%) 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.

The purpose of this study was to clarify the CT features of odontogenic myxoma.CT appearances were analysed in 17 patients with histologically verified odontogenic myxoma collected from five dental hospitals in Japan.On the CT images, tumour borders were generally well defined with a smooth margin both for bony and soft tissue structures in all patients. Cortical status was clearly evaluated using CT and the continuity was interrupted in nine patients. Intralesional trabeculations were observed in 13 patients. Of these 13, 6 patients showed the characteristic appearance of angular or straight trabeculations within the tumour. The trabeculations were frequently observed at the peripheral portion of the tumour. In three maxillary tumours, soft tissue margins were observed beyond the cortical margin and/or intralesional trabeculations. In 10 of the 13 lesions evaluated, the majority of the whole tumour area showed relatively lower density compared with surrounding muscles.CT clearly demonstrated characteristic features of odontogenic myxoma. CT analysis may contribute to establishing a consensus regarding the interpretation of conventional radiographic appearances in odontogenic myxoma.

The aims of this study were to determine the pathways of odontogenic infection spread into the submandibular space and their relationship to the clinical symptoms. Computerized tomography (CT) and magnetic resonance (MR) images of 33 patients with submandibular involvement were analyzed. The spread of infection was evaluated by lateral asymmetry of the shape and density of the fascial spaces and tissues, and by obliteration of the interfascial fat spaces. Imaging findings were classified into three types: in 19 patients (57.6%), infection spread through the mylohyoid muscle or sublingual space (type I). In five patients (15.2%), infection spread through the bony structures of the mandible with periosteal reaction or perforation of the cortical plate (type II) and was associated with relatively mild symptoms. In four patients (12.1%), infection spread from the masticatory space (type III). Seven of 11 patients with dysphagia or fever showed submandibular involvement spreading into the parapharyngeal space. CT and MR imaging clearly demonstrated different pathways of the spread of odontogenic infection into the submandibular space, which influenced the manifestation of clinical symptoms.

The aim of this study was to detect sonographic predictors for the efficacy of massage treatment of masseter and temporal muscle in temporomandibular disorders (TMDs) patients with myofascial pain.Thirty-seven TMD patients with myofascial pain (6 men and 31 women, a median age of 45 years) were enrolled. An oral rehabilitation robot massaged the patient's masseter and temporal muscles with a standard massage pressure of 10 N for 16 min. The standard treatment protocol was set five sessions every 2 weeks. The median total duration of treatment was 9.5 weeks. Efficacy of treatment was evaluated based on maximum mouth opening and visual analog scale scores of muscle pain and daily life impediments. The intramuscular echogenic bands and elasticity index ratios of the masseter muscles were evaluated on sonographic or sonoelastographic images obtained before treatment and after the third and last treatment sessions.The sonographic features detected different changes after the third treatment session between the therapy-effective and therapy-ineffective groups: in the therapy-effective group, the frequency of visibility of the distinct echogenic bands increased, and the elasticity index ratio decreased.Sonographic features after the third treatment session may be useful as predictors of therapeutic efficacy.

Summary Recent advances in orthognathic surgical techniques and orthodontic treatment, such as the use of dental implants for orthodontic anchorage, bone and tooth transplantation, and intraoral distraction for mandibular lengthening, have led to an increased demand for more advanced diagnostic image information than can be supplied by conventional radiography. In this article, the authors have reviewed several 3D imaging techniques that might be useful in this field. Currently, personal computers are equipped with such high processing speeds that it is easy to process interactively the image data of a complex 3D object and portray its dynamic properties in real-time. The powerful image-rendering capabilities of 3D CT may substitute for conventional radiographic examinations in the near future. Reducing the radiation dose to patients in spiral/helical CT scanning without impairing image quality, however, is a goal that must be achieved as soon as possible.14, 19 The limited cone-beam CT system seems to have an advantage because of the reduced radiation dose associated with the image data acquisition in a single rotation of the x-ray tube.1, 38 In the meantime, 3D imaging without any exposure to radiation and based on MR, ultrasound, or laserscanned image data is available to clinicians. The potential clinical applications of 3D imaging in dentistry represent a technologic advance that is rapidly becoming a reality that may far exceed anyone's expectations.

Objective. The purpose of this study was to evaluate the changes of blood flow of the submandibular gland in comparison with salivary secretion after gustatory stimulation through use of color Doppler sonography. Study design. High-frequency color Doppler sonography was performed on 30 healthy volunteers, aged 22 to 31 years. The prestimulation and poststimulation arterial blood flows were evaluated with color Doppler sonography and spectral analysis. Results. The means of prestimulation maximum and minimum velocities and pulsatility index of the submandibular gland were 6.35 ± 2.57 cm/sec, 1.79 ± 0.93 cm/sex, and 1.53 ± 0.42, respectively. After the stimulation, the color signals and velocities increased and the pulsatility index decreased. There was a close correlation between the increase in minimum velocity and that of salivary secretion. Conclusion. Color Doppler sonography is useful in analyzing changes in the blood flow of the submandibular gland caused by gustatory stimulation.

To clarify the diagnostic utility of CT in the evaluation of carcinoma of the maxillary gingiva and hard palate.The CT scans of 27 patients with squamous cell carcinoma of the upper gingiva and hard palate were reviewed. Tumor extent and bone destruction were compared with the surgical and histopathological findings to estimate the sensitivity, specificity and accuracy of CT.The primary tumor was detected by CT in 89% of patients. The grade of bone destruction determined by CT correlated well with that verified at surgery or by histopathological examination. The sensitivity, specificity, and accuracy of CT for invasion to the buccal mucosa were 64%, 89% and 75% respectively. For maxillary sinus invasion, CT showed low specificity but high sensitivity. The accuracy was 86% when the criterion for sinus invasion was the presence of an enhanced mass continuous with the primary tumor.CT is helpful for the evaluation of tumor extent in the upper gingiva and hard palate carcinoma. However, invasion of the maxillary sinus should be considered carefully, because CT findings suggestive of destruction of the floor of the maxillary sinus are not always consistent with sinus invasion.

Acute parotitis occasionally spreads rapidly down the neck with severe symptoms of swelling and pain. However, the inflammatory course of parotitis with extraglandular spread has seldom been described. On CT images, we have noticed a unique area just below the parotid gland that is surrounded by the platysma muscle and the superficial layer of the deep cervical fascia (DCF). In this case report, we describe the CT imaging features of acute parotitis, focusing on this area.

The study aimed to clarify the masseter muscle hardness in patients with myofascial pain, to examine their changes after massage, and to analyze whether the hardness can be an index for massage treatment. Sixteen patients with myofascial pain (12 with unilateral and 4 with bilateral masseter muscle pain) and 24 healthy volunteers were enrolled in this study. The masseter hardness between patients and the healthy volunteers was compared. The changes in the hardness in patients after massage were examined. The relation of the hardness with massage regimens and efficacies was analyzed. There was a significant right-and-left difference of the hardness in patients, although there was no difference in the healthy volunteers. The hardness decreased after massage. The pretreatment asymmetry index of the hardness showed a significant correlation with the massage pressure. It was concluded that there was a significant difference between the right and left masseter hardness in patients with myofascial pain. After massage treatment, the masseter hardness and right-and-left difference decreased. The hardness may be an index for determining the massage pressure.

To ascertain the normal range of maxillary sinus size and its changes with age on computed tomography (CT) and define convenient indices for sinus size, in addition, to examine the association of the height of the sinus floor with age and status of the dentition.The transverse and anteroposterior dimensions of the normal maxillary sinuses in 107 subjects were measured on axial CT and the relationship between these values and the sinus volume analysed. The height of the sinus floor was obtained by measuring the vertical distance from the anterior nasal spine to the sinus floor.The mean transverse and anteroposterior widths of the normal adult maxillary sinuses were 2.70 (s.d., 0.60) cm and 3.56 (s.d., 0.47) cm, respectively. There was a close correlation with sinus volume which could be predicted well from the multiple regression formula. These values increased up to the age of 20 y, but then decreased. There was no significant difference between subjects aged 50-79 years with and without maxillary premolars and molars. The width of the adult sinus correlated with the interzygomatic buttress distance and body weight. The mean height of the adult maxillary sinus floor was 0.37 (s.d., 0.44) cm inferior to the anterior nasal spine. It correlated negatively with sinus volume and fell with age up to 20 y, then rose again. In adults, it was not significantly influenced by the dentition status, and rose in proportion to the decrease in the interzygomatic buttress distance, and body height and weight.The transverse and anteroposterior widths of the maxillary sinus on axial CT are convenient indices for its size. The height of the sinus floor altered with changes in sinus volume, but was not directly influenced by the status of the dentition.

It is unclear whether computer-aided detection (CAD) systems for panoramic radiography can help inexperienced dentists to diagnose maxillary sinusitis. The aim of this study was to clarify whether a CAD system for panoramic radiography can contribute to improved diagnostic performance for maxillary sinusitis by inexperienced dentists.The panoramic radiographs of 49 patients with maxillary sinusitis and 49 patients with healthy sinuses were evaluated in this study. The diagnostic performance of the CAD system was determined. 12 inexperienced dentists and 4 expert oral and maxillofacial radiologists observed the total of 98 panoramic radiographs and judged the presence or absence of maxillary sinusitis, under conditions with and without the support of the CAD system. The receiver operating characteristic curves of the two groups were compared.The CAD system provided sensitivity of 77.6%, specificity of 69.4% and accuracy of 73.5%. The diagnostic performance of the inexperienced dentists increased with the support of the CAD system. When the inexperienced dentists diagnosed maxillary sinusitis with CAD support, the area under the curve (AUC) was significantly higher than that without CAD support. When the focus was only on panoramic radiographs in which CAD support led to a correct diagnosis, the AUC of the inexperienced dentists increased to an equivalent level to that of the experienced radiologists.The CAD system supported the inexperienced dentists in diagnosing maxillary sinusitis on the panoramic radiographs. If the accuracy of the CAD system can be increased, the benefits of CAD support will be further enhanced.

Objectives Shear-wave sonoelastography is expected to facilitate low operator dependency, high reproducibility and quantitative evaluation, whereas there are few reports on available normative values of in vivo tissue in head and neck fields. The purpose of this study was to examine the reliabilities on measuring hardness using shear-wave sonoelastography and to clarify normal values of masseter muscle hardness in healthy volunteers. Methods Phantoms with known hardness ranging from 20 to 140 kPa were scanned with shear-wave sonoelastography, and inter- and intraoperator reliabilities were examined compared with strain sonoelastography. The relationships between the actual and measured hardness were analyzed. The masseter muscle hardness in 30 healthy volunteers was measured using shear-wave sonoelastography.The inter- and intraoperator intraclass correlation coefficients were almost perfect. Strong correlations were seen between the actual and measured hardness. The mean hardness of the masseter muscles in healthy volunteers was 42.82 ± 5.56 kPa at rest and 53.36 ± 8.46 kPa during jaw clenching.The hardness measured with shear-wave sonoelastography showed high-level reliability. Shear-wave sonoelastography may be suitable for evaluation of the masseter muscles.

An increased attenuation area (IAA) is sometimes seen in the cystic cavity of odontogenic keratocysts (OKCs) on CT scans. The significance of IAA was compared radiologically and histologically in 26 cysts in which a provisional diagnosis of OKC had been made. First, the presence of IAA in the cystic cavity was assessed. Then, relationship between the presence of IAA and data obtained from the cysts, including the CT and histological findings and the visual appearance of the cyst contents, was evaluated. An IAA was frequently seen in large multilocular cysts. There was no relationship between the presence of IAA and aggressive features of the cyst on CT or the cyst contents. Histologically, subepithelial inflammation was often observed in the cysts with IAA. In order to ascertain whether the IAA was due to the keratin mass, a CT scan of a bundle of hair in a water bath was performed and shown to have a similar density. Our study demonstrated that IAA in cystic cavities results from desquamated keratin. Since this seems to occur in long-standing or inflamed multilocular OKCs, it could be used as a significant finding in the diagnosis of OKC.

An understanding of the age-related changes in the volume of the normal maxillary sinus will help to identify sinus abnormalities. Normal maxillary sinus volume was measured on axial CT scans in 115 cases, and analysed in relation to age, the presence of premolar and molar teeth, size of the midfacial skeleton and body height and weight. The volume ranged from 4.56-35.21 cm3 (mean: 14.71 +/- s.d. 6.33 cm3) in patients aged over 20 years. There was no significant sex difference and a close correlation between the two sides was found. The volume increased up to the age of 20 years, but then decreased. There was no significant difference in patients with and without maxillary premolars and molars between the ages of 50 and 79 years. The difference in right and left dentitions had no influence on the maxillary sinus volume over the age of 20 years. Adult maxillary sinus volume correlated with the interzygomatic buttress distance. In adult females, there was a significant correlation between the volume and the...

To the editor, Thank you for giving me the opportunity to respond to two letters submitted to Dentomaxillofacial Radiology concerning my recent publication: Ariji Y, Morita M, Katsumata A, Sugita Y, Naitoh M, Goto M, et al. Imaging features contributing to the diagnosis of ameloblastoma and keratocystic odontogenic tumours: logistic regression analysis. Dentomaxillofac Radiol 2011;40:133–140.

The aim of this study was to clarify the characteristic imaging features that can be used to differentiate ameloblastomas from keratocystic odontogenic tumours and to examine the significant imaging features contributing to a correct diagnosis.60 observers (39 specialists in oral and maxillofacial radiology and 21 non-specialists) examined CT and/or panoramic images of 10 ameloblastomas and 10 keratocystic odontogenic tumours shown on a webpage and made diagnoses. Their correct answer ratios were then calculated. The imaging features of the tumours were evaluated and expressed as binary numbers or quantitative values. The imaging features that contributed to a correct diagnosis were elucidated using logistic regression analysis.The mean correct answer ratio was 61.3% ± 17.2% for the diagnosis of ameloblastomas and keratocystic odontogenic tumours. CT images produced higher correct answer ratios for diagnosis of keratocystic odontogenic tumours by specialists. The significantly different imaging features between ameloblastomas and keratocystic odontogenic tumours were the degree of bone expansion and the presence of high-density areas. The significant imaging features contributing to a correct imaging diagnosis were the number of locules, the presence of high-density areas and the inclusion of impacted teeth.The presence of high-density areas is the most useful feature in the differential diagnosis of ameloblastomas and keratocystic odontogenic tumours based on comparison of the imaging features of both tumours and examination of the diagnostic contributions of these features.

Objective The aim of this study was to clarify the changes, using magnetic resonance (MR) images, in the masseter muscles caused by low-level static contraction. Study design Ten healthy male volunteers were enrolled in the study. The MR scans were performed before, immediately after, and 10 minutes after low-level static contraction. Two imaging sequences were acquired: a diffusion-weighted image and an iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) image. The apparent diffusion coefficient (ADC), the signal-to-noise ratio (SNR), and the thicknesses of the right and left masseter muscles were examined. Results The ADC and SNR immediately after exercise were significantly higher than those before exercise and 10 minutes after exercise. The muscles were significantly thicker immediately after exercise than before exercise and 10 minutes after exercise. Conclusion We confirmed the presence of edema in the masseter muscles caused by low-level static contraction using MR images.

Objectives The aims of this study were (1) to assess the diagnostic power of magnetic resonance imaging (MRI) for mandibular osteomyelitis through comparison with conventional techniques and (2) to establish practical MRI diagnostic criteria in relation to treatment and clinical outcome. Study design In 55 subjects, clinically suspected as mandibular osteomyelitis, signal intensities (SI) were evaluated on T1-weighted/short T1 inversion recovery (STIR) images. Results Forty-seven subjects were definitively diagnosed as having osteomyelitis by pathology studies or clinical course. For the acute or subacute stage, positively associated appearances were low SI on T1-weighted image and extensive high or focal high SI on the STIR image. For chronic stage, appearances of low SI on both T1-weighted and STIR images should be added to those for the acute or subacute stage. These findings support the at-present accepted imaging diagnostic criteria based on bony changes for detection of osteomyelitis. Conclusion This study confirms that T1-weighted/STIR images are useful for the detection of mandibular osteomyelitis.

To verify the use of a single coupling agent as a reference to obtain the elasticity index (EI) ratios and to investigate the EI ratios of the masseter muscles of healthy volunteers.Muscle phantoms with known elasticity (20, 40 and 60 kPa in the Young's modulus) were examined by strain-type sonoelastography using a coupling agent as the reference. Eight examiners tested soft (with 7 kPa) and hard (with 40 kpa) reference coupling agents separately. The correlation coefficients were determined between the EI ratio and Young's modulus of muscle phantoms. The interclass correlation coefficients were calculated for inter- and intraexaminer agreement.Strong correlations were found between the EI ratios and Young's modulus for both soft and hard references. The variations of the EI ratios were larger with soft coupling agents than those with hard coupling agents, and they increased in phantoms with 60 kPa elasticity. There were no differences in the EI ratios of the masseter muscle at rest between males and females or between the right and left sides. The ratio increased during clenching.The hard reference coupling agent was suitable for obtaining EI ratio of the masseter muscle. No differences were found in the EI ratios of the masseter muscle either between sexes or between the right and left sides at rest, and the ratios increased with the widening of their variations during clenching.

Objective To reveal computed tomography (CT) features of patients with coronoid process hyperplasia without interference between the process and the zygomatic bone. Study design A case-control study was designed. Thirteen cases without interference (2 male and 11 female, 28-56 years old) and 65 controls were sampled from a patient database. Differences in CT features were analyzed between the 2 groups regarding the following 7 points of 5 regions: configuration of the coronoid process, vertical level of the coronoid process, the distance between the bilateral zygomatic arches, thickness of the temporal muscle, anteroposterior width of the temporal muscle, thickness of the temporal muscle tendon, and thickness of the masseter muscle. Cluster analysis was applied to differentiate between individuals. Results All cases had bilateral hyperplastic change of the coronoid process. Differences were found between the cases and controls in 6 of 7 CT features with the exception of temporal muscle thickness. All incidences of significant difference showed larger values in the cases. All cases were clustered into the same group and were differentiated from the controls. Conclusion CT features appeared to be effective for diagnosis of this condition, and these patients should be put into the same category under the diagnosis of coronoid process hyperplasia.

Objective Following mandibular setback osteotomy, changes in the direction, length, and cross-sectional area of the masseter muscle were studied by means of computerized tomography (CT) images generated with a 3-dimensional (3D) reconstructive technique. Study design Pre- and postoperative CT examinations were performed on 17 prognathic patients treated by sagittal split ramus osteotomy with rigid osteosynthesis and 13 patients treated by intraoral vertical ramus osteotomy without osteosynthesis. The pre- and postoperative masseter muscle direction and length were evaluated using 3D CT images observed from a lateral viewing angle. The cross-sectional area of the masseter muscle was first measured on an axial CT image of a selected slice level, following which the right-angle cross-sectional area of the muscle was revised using the measured area from the axial image. Results Postoperatively, anterior tilting of the masseter muscle was observed; however, masseter muscle length was unchanged. Three months postoperatively, a significant reduction in the cross-sectional area of the masseter muscle was seen. A tendency to revert back to the normal dimension was seen between 6 months and 1 year postoperatively. No significant difference was noted between the 2 surgical techniques. Conclusions Three-dimensional computed tomography is an adequate imaging modality for masseter muscle evaluation. The results of this study suggest the masseter muscle may undergo reversible atrophy after mandibular setback osteotomy.

Objective The aim of this study was to investigate the pathways of infection originating in the maxillary teeth through the interpretation of computerized tomographic (CT) appearances. Study design CT images of 78 patients were analyzed with reference to lateral asymmetry of shape and density of fascial spaces and tissues. Results Changes in the alveolar cortical plates were observed more frequently in the labial/buccal side than in the palatal side. The facial expression muscles were involved in 23 (19.4%) patients. Infection caused by anterior teeth often spread into the levator labii superioris and levator anguli oris muscles. Deep spread into the fascial space was found in 9 (11.5%) patients. Masticator space changes were predominantly seen in the patients with infection caused by molars. Maxillary sinus changes were found in 57 (71.3%) patients with infection originating in the canines, premolars and molars. Conclusion Infection spread characteristics are related to the causal teeth, and the pathways were clearly demonstrated on CT images.

Objectives. The purpose of this study was to clarify the Doppler sonographic features of the facial artery in the anterior face in healthy volunteers and to investigate those of related hemangiomas. Study Design. Forty-six volunteers and 3 patients with hemangiomas were examined with Doppler sonography. The detection rates of the facial artery in the anterior face were determined. The features of the main trunk, superior and inferior labial branches, and the branches in the buccinator area were investigated together with the flow diameter, flow velocities, and resistive and pulsatility indexes. Results. The detection rates of the main trunk and superior and inferior branches were 100%, whereas that of the branches in the buccinator area was 92.4%. There were no significant differences in the measured values for all indexes between the right and left sides. However, there were significant correlations between right and left sides in the flow diameter and minimum velocity of the main trunk and in the flow diameter and pulsatility index of the superior labial branch. The Doppler sonographic features of the hemangioma were characterized as a hypoechoic area with internal and surrounding blood flows. Conclusions. Doppler sonography can clearly depict the facial artery and its branches in the anterior face, and this method appears to be useful in the follow-up examination of hemangiomas in this area. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;93:195-201)

Muscle oedema, which can be seen as a thickness increment by ultrasonography, is important in provoking pain and fatigue during low-level contraction. Although oedema is related to the balance of inflow and outflow of blood, there are no data on the correlation between muscle thickness change and blood-flow. Blood-flow velocities in the facial artery and the muscle thickness changes were measured by colour Doppler ultrasonography in 30 healthy volunteers during 20 min contraction with 10% of maximum force. Thickness and velocity changes both reached a peak in the initial phase of contraction. The initial change of thickness did not correlate with the velocity in the facial artery, while those immediately after exercise showed a high correlation. The velocity changes in the facial artery might depend on both the general response to contraction and local metabolic or mechanical factors in the contracted masseters.

Objective: The purpose of this study was to clarify the normal findings of arteries in and around the masseter muscle and to present their pathologic changes with the use of color Doppler sonography. Study Design: The vascular appearances were examined for the 4 main arteries feeding the masseter muscle in healthy volunteers (n = 38) and patients with inflammation (n = 5) and intramuscular hemangioma (n = 3). The features of these arteries were investigated together with the flow diameter, flow velocities, and arterial resistances. The symmetry indices were also calculated to assess the pathologic changes. Results: The detection rates of the branch from the transverse facial artery, the masseter artery, and the branch from the maxillary or external carotid artery were 98.7%, 21.1%, and 84.2% in healthy volunteers, respectively. The facial artery that feeds the muscle from the inferior part represented 2 patterns according to anatomic variant: the masseteric branch (22.4%) and the main trunk itself (77.6%). The means of the flow diameter, maximum and minimum velocities, resistive index, and pulsatility index in healthy subjects were 1.8 mm, 24.6 cm/s, 5.1 cm/s, 0.80, and 2.51, respectively. In most of the patients with symptoms, the symmetry indices of all measurement values increased in comparison with those of healthy volunteers. Conclusion: Color Doppler sonography is useful in describing the arteries in and around the masseter muscle and has the potential of being used to depict the pathologic changes. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;91:472-82)

Objective. The purpose of this study was to evaluate the subjective quality of Joint Photographic Experts Group (JPEG) compressed images of intraoral radiographs with file sizes of 30 kilobytes or less, which can be transmitted quickly on the World Wide Web. Study design. Conventional intraoral radiographs were digitized at sampling rates of 100, 200, 300, 400, and 600 dots per inch through use of a flatbed scanner and saved in JPEG format in 11 compression degrees. Fifty-five combinations of sampling rate and compression degree were evaluated by means of a visual analog scale. Sampling rate and compression degree combinations whose quality was inferior to that of an average image were excluded. The quality of the remaining combinations was subsequently evaluated through assessment of 8 anatomical features in each image. Results. Forty of the 55 combinations provided a file size less than 30 kilobytes. Thirty combinations obtained VAS scores of 0 or higher on the standardized VAS. As a result, 16 combinations of sampling and compression conditions were selected for the second part of the study. Only one combination of sampling rate and compression degree was found to provide sufficient image quality for all 8 anatomical features. Conclusions. Under the file size limit of the study design, the full-sized compressed image of an intraoral radiograph did not always provide sufficient quality. This problem will be reduced by improvements in telecommunications infrastructure, which will permit faster transfer of files of larger size. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;88: 93-9)

An oral and maxillofacial radiology teaching file on the World Wide Web was created effective June 15, 1995. The file contains 106 cases (279 images) of 94 diseases in the oral and maxillofacial region.