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Objective The objective of this study was to investigate the difference of the temporomandibular joint (TMJ) between deviated and nondeviated sides of the mandible in adult patients with mandibular deviation. Study design TMJ size, disk displacement, and clinical symptoms of 28 patients were examined clinically and by magnetic resonance imaging (MRI). Twelve age- and sex-matched control subjects were also used to evaluate which side of the mandible in patients was similar to the control. Results The TMJ on the deviated side showed a smaller condyle and a higher incidence of disk displacement than the nondeviated side and those in the controls. However, the clinical symptoms showed no differences between the deviated and nondeviated sides, and no association with disk displacement. Conclusions Our results suggest that the deviated side was the abnormal side and may have some association with mandibular deviation. However, the clinical symptoms could not indicate those differences.

We present 3 cases of Sjögren's syndrome in which multiple sialolithiasis were observed in the parenchyma of the parotid gland. The sonographic examinations showed microliths that were observed as hyperechoic spots. Some of the microliths were accompanied with comet sign, however most of them showed no particular posterior echoes. None of them showed acoustic shadows, which are normally observed in cases with sialolithiasis. We were able to prove that some of the hyperechoic spots observed sonographically in patients with severe Sjögren's syndrome were microliths. Although these multiple microliths are rarely detected, they may exist potentially in higher frequency in patients with severe Sjögren's syndrome.

Objective We sought to clarify the correlation among a computed tomography (CT) or a panoramic radiography (PR) pattern of bone destruction, a histologic pattern of bone destruction, and a mode of invasion in carcinoma of the mandibular gingiva. Study design CT images, panoramic radiographs, and decalcified, hematoxylin-eosin–stained preparations of the excised mandibular bone of 62 patients with carcinoma of the mandibular gingiva were retrospectively evaluated. Each computed tomograph, panoramic radiograph, and the histologic pattern of bone destruction was classified as 1 of 5 types: erosive , erosive and partly mixed , mixed , mixed and partly invasive , or invasive . The mode of invasion of the tumor was also assessed with a hematoxylin-eosin–stained preparation of the initial biopsy specimen. The relationships among the CT pattern, the PR pattern, the histologic pattern of bone destruction, and the mode of invasion of the tumor were statistically analyzed by using the Spearman rank correlation test. Results The CT pattern ( P = .005) and the PR pattern ( P = .003) were significantly correlated with the histologic pattern with respect to the bone destruction. The CT pattern ( P = .996), the PR pattern ( P = .997), and the histologic pattern ( P = .521) of bone destruction were not correlated with the mode of invasion seen in the biopsy specimen. Conclusion The CT pattern and the PR pattern of bone destruction reflect the histologic pattern of bone destruction caused by carcinoma of the mandibular gingiva but are not associated with the mode of invasion of the tumor.

Objectives. We sought to evaluate the diagnostic efficacy of computed tomography (CT) images in the differentiation between intraosseous malignant tumors and osteomyelitis spreading into the masticator space. Study Design. A retrospective evaluation was carried out by using CT images from 12 patients with intraosseous malignant tumors and 9 patients with osteomyelitis involving the masticator space and accompanying mandibular bone destruction. The following CT observations are discussed: (1) bone destruction pattern subdivided into spotty, gross, or permeative; (2) cortical bone expansion; (3) diffuse osteosclerotic changes; (4) periosteal reaction; (5) masticator muscle involvement; (6) enlargement of the facial muscle; and (7) attenuation in the subcutaneous adipose tissue. Results. The pattern of permeative bone destruction, cortical bone expansion, and the enlargement of both the masseter and medial pterygoid muscles were all observed in patients with malignant tumors. In contrast, diffuse sclerotic change and a periosteal reaction were significant observations in patients with osteomyelitis. Conclusion. The efficacy of CT in establishing a differential diagnosis of malignant tumors or osteomyelitis is supported by this study. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2003;95:503-509)

Objective. The purpose of this study was to investigate the ability of contrast-enhanced magnetic resonance imaging to differentiate hemangioma from lymphangioma in the oral and maxillofacial region. Study design. Contrast-enhanced magnetic resonance imaging was performed in 20 patients (21 masses: 17 hemangiomas and 4 lymphangiomas) through use of either a 0.2-T permanent system or a 0.5-T superconductive system and spin-echo pulse sequences. Results. After intravenous administration of contrast medium, enhancement was observed in all hemangiomas in areas corresponding to those with high signal on T2-weighted images. Unequivocally increased signal was observed in 10 masses, and slightly increased signal was observed in 7 masses. On the other hand, none of the lymphangiomas showed an enhancing mass on contrast-enhanced T1-weighted images. Conclusions. Although contrast-enhanced T1-weighted imaging may not improve delineation of masses in all cases, it can be used to differentiate between deep hemangiomas and lymphangiomas. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;88:496-500)

Six patients with mucoepidermoid carcinoma in the mandible were studied with both panoramic radiography and computed tomography. Lesion shape and margin were evaluated on panoramic radiography, and bony expansion and cortical plate destruction were evaluated on computed tomography. In addition, a possible correlation among radiographic findings, histologic findings, and prognosis was investigated. Lesions found on panoramic radiography were classified into three types; each type pertained to two of the six patients. The lesion types were as follows: cystic, characterized by a large, cystic radiolucent area; rarefying, characterized by rarefying changes of the trabeculae; and infiltrative, characterized by a central ill-defined area of bony destruction. The results show that computed tomography is useful in the identification of tumor extent, bony expansion, and cortical plate destruction resulting from tumors. None of the patients whose lesions were of the cystic or rarefying type showed evidence of disease after surgery. In contrast, both of the patients whose lesions were of the infiltrative type died of their tumors. Histologic findings of the cystic and rarefying types showed tumors that were well-differentiated or moderately well-differentiated, whereas findings of the infiltrative type showed poorly differentiated tumors. Radiographic findings correlated with histologic findings and prognosis of mucoepidermoid carcinoma in the mandible in this limited series.

Objective. The purpose of this study was to investigate the effect of interleukin-1 on cells from loose bodies of synovial chondromatosis of the temporomandibular joint. Study design. The cells were isolated from uncalcified loose bodies in a case of synovial chondromatosis of the temporomandibular joint and cultured in α-MEM medium containing 10% fetal bovine serum. The cells were treated with or without interleukin-1α and then stained with toluidine blue. Their conditioned media were analyzed with gelatin zymography to detect matrix-degrading proteinase(s). Results. The cells from loose bodies produced toluidine-blue-stained matrix. When the cells were treated with 100 ng/ml of interleukin-1α for 3 days, toluidine-blue-stained matrix was strikingly reduced. Gelatin zymography revealed that interleukin-1α-treated cells released 62-kDa gelatinase. Conclusions. Interleukin-1α may lead loose-body-derived cells to degrade the cartilaginous matrix of loose bodies in synovial chondromatosis of the temporomandibular joint.

A case of squamous cell carcinoma of the tongue is reported with emphasis on an atypical finding of cervical lymph node metastasis visible on computed tomography. Multiple cervical lymph nodes revealed a high computed tomographic value of about 330 HU, lower than that of calcification. The lymph nodes revealed well-defined elliptical hyperechoic masses with an echogenic line and posterior shadow on ultrasonography. The appearance of a high density mass on computed tomography with a computed tomographic value lower than that of calcification may be a reliable finding of metastasis because it demonstrates the presence of marked keratinization produced by squamous cell carcinoma.

Objectives. The purpose of this study was to evaluate quantitatively observer performance with ultrasonography and sialography in the diagnosis of parotid gland involvement of Sjogren's syndrome. Study design. Sixty-four parotid gland sialograms and 65 ultrasonograms were prepared for observer performance experiments. They included both modalities in 24 Sjogren's syndrome and 19 nonspecific parotitis cases, 21 normal parotid gland sialograms, and 22 normal ultrasonograms in healthy volunteers. The images were randomly sequenced and presented to five observers who were asked to describe several findings and finally to determine the imaging diagnosis by ranking the abnormal features and the diagnosis on a five-point-rating scale. Observer performance was evaluated on the basis of the reliability of findings interpreted and the diagnostic accuracy of each modality from observers' rating scores. Results. The diagnostic accuracy of sialography was very high, nearly perfect. The diagnostic accuracy of ultrasonography was lower than that of sialography; resulting from the lower incidence of characteristic findings in the disease groups and lower sensitivity on ultrasonography. In the differentiation of Sjogren's syndrome from the normal, however, the diagnostic accuracy of ultrasonography increased to 80% for all cases, and up to nearly 90% in the advanced sialographic stages. Conclusion. Ultrasonography is useful for the diagnosis of Sjogren's syndrome in the advanced stages. Taking the noninvasiveness of this technique into account, we recommend first applying ultrasonography to the diagnosis of Sjogren's syndrome and performing sialography when no positive findings are detected on ultrasonography.

The aim of this study was to describe the CT, MRI and ultrasonography findings of five cases of neurogenic tumours in the head and neck region.Five neurogenic tumours were analysed with respect to their CT value, the presence of cystic change, target sign, lobulation, connection to the nerve and vascularity.The contrast-enhanced CT (ECT) of the schwannomas demonstrated either a mass with low enhancement (two out of three cases), which reflected the predominant Antoni B components, or a mass with cystic changes, which was an Antoni A-based schwannoma displaying cystic changes (one out of three cases). On MRI, all tumours showed homogeneous and isointense signals for muscle on T₁ weighted images (T₁ WIs). T₂ weighted images (T₂ WIs) and gadolinium (Gd)-enhanced T₁ WIs demonstrated target sign in both schwannomas. Ultrasound examination showed a well-defined, ovoid or round hypoechoic mass. The direct connection to the nerve was demonstrated in two of the five cases. Lobulation was observed in only one of the five cases and cystic changes were observed in one of the five cases. In all of the cases, no vascularity was seen in power Doppler images (PDIs) obtained percutaneously.Low-enhanced areas on ECTs can be specific for schwannomas, which suggests the predominance of Antoni B components. The target sign on T₂ WIs and Gd-enhanced T₁ WIs can be specific, which can be used to differentiate the two different components (Antoni A and Antoni B). The direct connection to the nerve can be a specific finding for neurogenic tumours; however, at present the sensitivity is 40%.

This article describes the computed tomographic and conventional radiographic findings for florid cemento-osseous dysplasia. A low-density thin layer or cystlike area was observed around the high-density masses in the tooth-bearing area in the seven cases studied. Expansion of the buccal and lingual cortical plates was observed in association with cystlike areas, but was infrequently observed in florid cemento-osseous dysplasia not having such areas. The computed tomographic number of the high-density masses ranged from 772 to 1587 Hounsfield Units and was equivalent to that of cementum or cortical bone.

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.

Mandibular osteomyelitis often is associated with involvement of the masticator space. Assessment of mandibular osteomyelitis should therefore involve assessment of soft tissue involvement of the lesion. The purpose of this study was to clarify the relationship between computed tomography patterns and the presence of inflammation in soft tissues. Thirty-three cases diagnosed with osteomyelitis of the mandible were analyzed radiologically with conventional radiographs and with computed tomography scans. Computed tomography patterns of osteomyelitis were classified into four types, lytic, mixed, sclerotic, and sequestrum patterns. Location, extent of the lesion, and change of the cortical plate were evaluated and compared with conventional radiographic findings. Mixed pattern cases displayed diffuse bone abnormalities, which sometimes were accompanied by cortical plate disruption and periosteal reaction. In addition, most mixed pattern cases showed soft tissue involvement, especially of the masseter muscle. Inflammation of the masseter muscle was found to be related to periosteal reaction and disruption of the buccal cortical plate. The data demonstrate a close interaction between cortical plate disruption and muscle inflammation. The extent of inflammation including soft tissue involvement was better appreciated with computed tomography in osteomyelitis, especially in mixed pattern cases.

Eleven patients with oral and maxillofacial angiomas (seven hemangiomas and four lymphangiomas) were evaluated with magnetic resonance imaging using a 0.2-T permanent system and spin-echo pulse sequences. These lesions typically had signal intensities that were iso T1-weighted, similar to muscle, and high T2-weighted, greater than subcutaneous fat. Nine tumors had well- or relatively well-defined margins, and seven cases had curvilinear structures of low signal intensities in the masses on T2-weighted images. It was impossible to distinguish hemangiomas from lymphangiomas on MR images. Our experience suggested that most angiomas of oral and maxillofacial regions present special characteristics on magnetic resonance images. It is thought that information obtained with magnetic resonance images can contribute significantly to the evaluation of the extent of these lesions.

Fifteen cases (16 concavities) of the so-called "Stafne's bone cavity" were investigated with the use of computed tomography. The sizes, bony outlines, and contents were analyzed on axial images. In all cases, computed tomography clearly demonstrated the concavities on the lingual surface of the mandible. There were no empty concavities. The bony outlines and contents were divided into three types. The concavities with a portion of submandibular gland as a content were larger than those with other contents. Four of six concavities not extending to the buccal cortical plate were filled solely with fat tissue, whereas all concavities with expansion of the buccal cortical plate contained submandibular gland.

Nine cases of open lock position of the condyle of the temporomandibular joint (TMJ) are reported. In two patients recurrent dislocation of the TMJ was diagnosed clinically, and four had previous episodes of anterior dislocation. An arthrotomographic examination revealed that the condyles of the affected TMJs were located anterior to the anterior bands of the disks at an open-mouth position. An arthrographic fluoroscopic examination showed that the anterior bands mechanically obstructed the anteriorly displaced condyles from posterior movement into the articular fossae to various degrees at open-mouth position. One cause of anterior dislocation of the TMJ is thought to be fixation of the condyle in the open lock position resulting from a disturbance of a neuromuscular mechanism. In the two patients with dislocation, occlusal treatment eliminated muscular symptoms and the dislocations completely disappeared.

To correlate diagnostic accuracy for proximal caries with perceptibility of low contrast image details using regression analysis. The other purpose was to determine the attenuation range required for proximal caries diagnosis.The results of the two types of observer performance tests described above were retrieved from previous studies. Recording media included in those studies were the Compuray and the Dixel, direct digital radiographic systems, and Ektaspeed Plus film. The average numbers of perceptibility of image details from five observers were calculated for each step and for every combination of contiguous steps of the aluminium test phantom from the perceptibility test. The average diagnostic accuracy for proximal caries from the same five observers was correlated with the total number of perceptible details from the phantom using regression analysis. Finally, attenuation range required for proximal caries diagnosis was calculated from the attenuation range of the phantom where the maximum correlation coefficient was obtained.Maximum correlation (r=0.68) was obtained at the combination of five contiguous steps of the aluminium test phantom. Attenuation range required for proximal caries diagnosis corresponded to the 2 mm to 6 mm thickness of aluminium with acrylic block of 12 mm thickness.There is a correlation between perceptibility of low contrast image details and diagnostic accuracy for proximal caries. There may be a possibility to simplify observer performance tests for proximal caries diagnosis by using the standardized phantom simulating its attenuation range.

To elucidate the effect of automatic exposure compensation (AEC) on the diagnostic accuracy of proximal caries by comparing several digital intraoral imaging systems with a film.Twenty-seven extracted teeth served as proximal caries samples. Three digital radiographic systems; the Compuray, the Dixel, and the Sens-A-Ray without scintillator layer, and Kodak Ekta-speed Plus films were used as recording media. Radiographs of the teeth samples were obtained with each recording medium under seven to eight different exposures including the optimum level. Six oral radiologists evaluated the possibility of proximal caries with the five-grade-confidence-scale. On digital radiographs, image manipulations were allowed after the initial assessment. Receiver operating characteristic (ROC) curves were obtained at each exposure in each recording medium. The area under the ROC curve (Az) was used as the representative value of diagnostic accuracy. Diagnostic accuracy (DA) curves were obtained by plotting averaged Az values from all observers as a function of incident exposure in each system.The effect of exposure variation on the DA was slight in the film while it was significantly larger in the digital systems without AEC. Among digital systems, the effect of exposure variation was smaller in the system with AEC than those without AEC. There was no significant effect on the diagnostic accuracy even if digital image manipulation was employed.AEC minimizes the decrease of DA due to inadequate exposures. Since it compensates for the narrow exposure range in the digital intraoral sensor systems, the system with AEC may be preferable for the clinical diagnostic tasks.

To clarify the valuable clinical features and diagnostic imaging findings regarding the diagnosis of osteosarcoma of the jaw (OSJ).The initial symptoms and diagnostic imaging findings of 10 patients with OSJ were analysed. The points analysed on the diagnostic images were as follows: any widening of the periodontal ligament space of the teeth on the periphery of the OSJ; the presence of radial spicules and Codman's triangle; any signs of bone destruction; and the patterns of osteogenesis.All patients had pain and/or swelling of the affected site, and all OSJs, except for one edentulous case, showed a widening of the periodontal ligament space of the teeth on the periphery of the OSJ. Radial spicules or Codman's triangle were observed in only three cases (30%). Four out of five mandibular OSJs were osteolytic or osteolytic dominant with bone destruction, while, in contrast, four out of five maxillary OSJs were osteogenic or osteogenic dominant, and three out of the four maxillary OSJs did not show bone destruction. The osteogenic OSJ without bone destruction was similar to some benign cemento-osseous lesions of the jaw and thus was difficult to diagnose as OSJ based on the diagnostic imaging findings alone.Even though some OSJ showed features similar to the benign tumours of the jaw bone based on the diagnostic imaging findings, the pain and swelling of the affected site, and the widening of the periodontal ligament space of the teeth on the periphery of OSJ were considered to be common findings, which may help in making an accurate diagnosis of OSJ in this limited series.

To compare psychophysical properties of two intraoral films and three digital systems using the perceptibility curve (PC) test.A test object was used to determine the exposures and exposure differences between the total thickness of the test object and details consisting of holes of increasing depth. The PCs for the two intraoral films, UltraSpeed and EktaSpeed Plus, were constructed employing exposure and exposure differences from dose response functions. Integrals of the PCs were calculated to obtain the psychophysical properties of the two films. Psychophysical properties of the two films were compared with those of the three digital systems published previously (CDR, Dixel and Digora).The PC for the EktaSpeed Plus showed a slightly higher peak than that for the UltraSpeed. Available exposure ranges were comparable. The PC for the EktaSpeed Plus was shifted to the left of the exposure axis indicating its higher sensitivity as compared with UltraSpeed. All three digital systems had narrower but higher peaks compared with the films. The integrals for the digital systems were considerably larger than those for the two film types.All the three digital systems have superior psychophysical properties compared with the two tested films.

Objective. The purpose of this study was to review and illustrate the appearances on diagnostic images of pathologic conditions of the buccomasseteric region. Study design. Computed tomographic, sonographic, and magnetic resonance images of the buccomasseteric masses were reviewed retrospectively. Results. In our series of 66 cases, there were 60 benign lesions; of these, 21 were benign masses, 11 were inflammations, and 28 were myopathies. The most common pathologic condition of the buccomasseteric region was masseteric hypertrophy (n = 22). The most common lesion manifesting as a benign mass in this series was hemangioma (n = 10), which was followed by lipoma (n = 6). Six of the 66 patients had malignant tumors. Conclusions. Computed tomography and magnetic resonance imaging were useful in demonstrating the location and extent of the buccomasseteric masses. Sonography provided clear images of internal architectures of the mass in this region.

The purpose of this study was to clarify the diagnostic value of magnetic resonance imaging for malignant tumors in the oral and maxillofacial region. Computed tomography and magnetic resonance images of 25 patients with malignant tumors of the oral and maxillofacial region were evaluated. Computed tomography scans were performed with intravenous contrast enhancement. A 0.2-Tesla (Hitachi Medical Corp., Tokyo, Japan) permanent magnetic resonance unit was used to obtain T1-, T2-, and proton-density-weighted images with spin-echo pulse sequences. Gadolinium-diethylene-triamine-pentaacetic acid was administered in 11 cases. Severe artifacts influencing image interpretation were observed in 10 (40%) cases on computed tomography but only in 5 (20%) cases on magnetic resonance imaging. There was no difference in the detectability of bone invasion between images from the two systems. Contrast enhancement with gadolinium-diethylene-triamine-pentaacetic acid provided additional useful information in only 3 of 11 cases compared with nonenhanced magnetic resonance images. Malignant tumors showed a higher signal intensity than that of muscle on T2-weighted images in all cases and on proton-density-weighted images in 23 (92%) cases. On T1-weighted images, an intermediate signal intensity similar to that of muscle was seen in 16 (64%) cases and a hyperintense signal in 9 (36%) cases. There was poor correlation between signal intensity and pathologic diagnosis of the tumors. These results suggest that in cases with severe artifacts that disturb the interpretation of the images on computed tomography, magnetic resonance examinations are preferable for defining the exact extent of the primary lesion.

Summary The bone invasion in carcinoma of the mandibular gingiva (CaMG) is one of the important factors to determine the treatment planning and predict the prognosis. Japan Society for Oral Tumors proposed a new criterion of T4 classification of CaMG in 1997 as follows: the tumor is classified as T4 when the tumor spreads into the mandibular canal, and the tumor should not be classified as T4 when the tumor does not invade into the mandibular canal. Thus, the supero-inferior extent of bone invasion is one of the important diagnostic factors on Images. The accuracy of the supero-inferior extent of bone invasion by diagnostic images is equal between panoramic radiography (PR) and CT, and hence, PR would be suitable for the initial screening modality to survey the bone invasion into the mandibular canal. However, regarding the pattern of bone invasion by CaMG, the CT pattern of bone invasion is associated with the prognosis, and therefore the pattern should be determined based on the CT findings. In conclusion, at the present time, CT is suitable for detection of bone invasion in CaMG, although CT cannot detect precisely an early weak bone invasion, or a bone invasion infiltrating through the trabecular bone.