Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

OBJECTIVES: To examine the diagnostic usefulness and procedures of ultrasonography (US) for mass lesions in the soft tissue of the oral region. METHODS: This study involved patients with mass lesions (tumorous lesions and cysts) who had undergone US and histopathological examinations from January 2017 to December 2019. The following points were evaluated by two observers using an evaluation scale: vascularity, echo intensity level, boundary, margin shape, distribution of internal echoes, and capsule. The usefulness of each point for differential diagnosis of tumorous lesions and cysts was statistically analyzed. RESULTS: Forty-five mass lesions in the soft tissue of the oral region (33 tumorous lesions and 12 cysts) were analyzed. There were significant differences in four evaluation points between the tumorous lesions and cysts: vascularity, echo intensity level, boundary, and margin shape. Cysts were almost completely excluded diagnostically, especially when vascularity was observed. There were also significant differences in two evaluation points between nonvascular tumorous lesions and cysts: echo intensity level and boundary. CONCLUSIONS: In US examination for mass lesions in the oral region, it was possible to diagnose tumorous lesions and exclude cysts when vascularity was observed. When vascularity was not observed, however, tumorous lesions and cysts could be identified using two evaluation points: echo intensity level and boundary.

DOI： 10.1007/s11282-022-00605-2

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Purpose: To focus on the effects of the presence of mesiodens on adjacent teeth and to investigate the timing of its safe removal. Materials and Methods: Cone-beam computed tomography examinations, obtained at Okayama University Hospital over a three-year period, were inspected. Data were recorded including the number of mesiodens; associated abnormalities; and the relationship with neighboring structures. Depending on multiple factors, the risk of developing complications due to early extraction of a mesiodens was divided into three categories: high, medium, and low risk. Results: A total of 5,958 cone-beam computed tomography exams were obtained, 460 patients aged 3-85 years were diagnosed with a total of 568 mesiodens, 382 (67.3%) of which were discovered in young patients (age <10 years), and 333 (87.2%) of these were associated with abnormalities. Regarding the risk categories, 11 (1.9%) were considered to be in the high-risk, five (0.9%) in the medium-risk and 552 (97.2%) in the low-risk categories. Moreover, eight out of 11 high-risk mesiodens were extracted and no post-operative complications have been seen. Conclusion: As the results showed that no postoperative complications were seen in all the extracted cases of high-risk mesiodens, this indicates the possibility of safe extraction at an early age which could reduce related future complications.

DOI： 10.5624/isd.20210218

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BENTHAM SCIENCE PUBL LTD  

Background:An odontogenic myxoma is an intraosseous tumor characterized by stellate and spindle-shaped cells embedded in an abundant myxoid or mucoid extracellular matrix. We herein describe an odontogenic myxoma that expanded not only to the bone marrow but also to the outside of the alveolar bone. Diagnosis of an odontogenic myxoma in a tooth-deficient region by imaging findings alone was difficult because the positional relationship between the tumor and the tooth is unknown. Furthermore, some of these odontogenic myxomas reportedly show rapid growth.Case Report:Here, we present the case of a patient, a 44-year-old man, who had a hard, bone-like swelling on his right mandible molar region and mild paresthesia on his right cheek. An odontogenic myxoma and ameloblastoma were suspected based on the imaging findings; however, pathological examination of the biopsy led to a diagnosis of odontogenic myxoma. Right segmental mandibulectomy was performed, and there was no recurrence observed after surgery.Conclusion:To improve the accuracy of imaging diagnosis, it is important to compare the imaging findings with the pathological findings of the surgical specimen. This comparison in the present case revealed differences in the magnetic resonance imaging signal intensity in regions with different types of cell components.

DOI： 10.2174/18742106-v16-2202140

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPANDIDOS PUBL LTD  

Immune checkpoint inhibitors (ICIs) targeting programmed death ligand-1 (PD-L1) are highly promising therapies for oral squamous cell carcinoma (OSCC). The assessment of PD-L1 expression may help predicting the therapeutic effect of ICIs and, thus, benefit patient selection. Contrast index (CI) parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) have been proven as efficient to assess microvessel density (MVD) in OSCC. The present study aimed to determine the correlation between DCE-MRI parameters and MVD and between DCE-MRI parameters and PD-L1 expression to determine whether DCE-MRI could be used non-invasively to evaluate PD-L1 expression in patients with OSCC. A total of 21 patients with primary OSCC who had undergone a 3T MRI scan, including DCE-MRI, were included in the present study, and CI curve-derived parameters were examined. The MVD and PD-L1 expression in the surgically resected specimens were analyzed using immunohistochemistry (IHC) staining for CD31 and IHC staining for PD-L1, respectively. The results demonstrated that the expression levels of these markers were correlated with DCE-MRI parameters. PD-L1 expression levels were found to be significantly correlated with the maximum CI (CI-max; P=0.007), peak CI (CI-peak; P=0.007), maximum CI gain (CI-gain; P=0.006) and MVD (P=0.001) values. The mean CI-max, CI-peak, CI-gain and MVD values were significantly higher in tumors with high PD-L1 expression (P<0.05). MVD levels were also significantly correlated with the time of CI-max (T-max; P=0.003) and CI-gain (P=0.037). The mean CI-gain was significantly increased, and the mean T-max was significantly shorter in high MVD tumors (P<0.05 and P<0.01, respectively). In summary, the findings from the present study confirmed the correlation between CI parameters, derived from DCE-MRI, and MVD, and suggested that these parameters may be correlated with PD-L1 expression in OSCC tumor cells.

DOI： 10.3892/ol.2021.13039

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The purpose of this study was to evaluate the risk of injury to the facial (FA) and related arteries during mandibular third molar (MTM) extraction using contrast-enhanced computed tomography (CE-CT). CE-CT images of the MTM region were retrospectively reviewed. The area of the MTM was equally divided into three zones in the coronal images from mesial to distal, that is, zone 1, zone 2, and zone 3. The FA, submental artery (SMA), and sublingual artery (SLA) were identified. The distance from the mandible to FA, SMA, and SLA and the diameter of the FA, SMA, and SLA was measured in three zones, respectively. The thickness of the facial soft tissues and width of the mandible were measured at their maximum. The mean distance from the FA to the buccal cortical bone in zone 1, zone 2 and zone 3 was 2.24 mm, 2.39 mm and 1.67 mm, respectively. The SMA and SLA were found to be distal to the mandible. The mean diameter of the FA was 1.26 mm in males and 1.04 mm in females, respectively (p < 0.0001). The distance between the FA and buccal cortical bone of the mandible, and the patients' weight showed moderate correlation in zones 1 and 2. Based on our findings, the FA can be damaged if the surgical invasion reaches the facial soft tissues during MTM surgery. The patients' weight might be a good predictor for FA injury when CE-CT is not available.

DOI： 10.1002/ca.23779

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Language：Japanese   Publisher：(公社)日本歯科医師会  

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Language：Japanese   Publisher：(公社)日本歯科医師会  

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Language：Japanese   Publisher：(NPO)日本歯科放射線学会  

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Language：Japanese   Publisher：(一社)日本病理学会  

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OBJECTIVES: The purpose of this study was to evaluate the usefulness of Hounsfield unit (HU) assessment with multislice-CT in the differentiation of radicular cysts (RCs), dentigerous cysts (DCs) and odontogenic keratocysts (OKCs). METHODS: In total, 307 odontogenic cysts (RCs, DCs and OKCs) were included in this study. Cysts with lesion diameter <10 mm, cysts with artefacts affecting measurement of HU values, cysts involving infection and recurrent cysts were regarded as exclusion criteria. Images were acquired in three different types of CT scanners: Aquilion ONE, Discovery CT750 HD and SOMATOM Definition Flash. Differences in HU values among scanners and among types of odontogenic cysts were assessed using one-way analysis of variance; multiple comparisons were performed post hoc, using the Tukey-Kramer honestly significant difference test. RESULTS: In total, 164 cysts were analysed in this study (64 RCs, 57 DCs and 43 OKCs). Regardless of the type of lesion, the Aquilion ONE scanner demonstrated a significant difference in HU value, compared with the Discovery CT750 HD scanner. Regardless of CT scanner model, HU values significantly differed between DCs and OKCs (p < 0.0001), as well as between OKCs and RCs (p < 0.0001). CONCLUSIONS: HU values were found to vary among CT scanners and should always be associated with other lesion imaging features while interpreting and elaboration diagnostic hypothesis. Notably, the results suggested that OKCs might be able to be differentiated from DCs and RCs by using HU values.

DOI： 10.1259/dmfr.20200188

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Language：Japanese   Publisher：岡山歯学会  

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Language：Japanese   Publisher：岡山歯学会  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPANDIDOS PUBL LTD  

The numbers of abnormal findings incidentally detected in adjacent regions are increasing with advances in imaging modalities. The present study aimed to examine the prevalence and characteristics of incidental findings in the thyroid gland on computed tomography (CT) images of the oral and maxillofacial region. CT scans of the oral and maxillofacial region in patients obtained between January 2012 and December 2016 were retrospectively reviewed. Images that revealed incidental findings in the thyroid gland, including nodules, were recorded, together with the sizes and characteristics of the findings. The Japan Association of Breast and Thyroid Sonology (JABTS) guidelines were used for classification. The rate of descriptions of these findings in the radiographic interpretation reports were also examined. Of the 1,135 patients examined, 326 (28.7%) had several types of incidental findings. In particular, 169 (14.9%) of the 1,135 patients had nodules >5 mm in diameter, for which further careful examination is recommended in the JABTS guideline. The description rate for nodules >5 mm in diameter in the radiographic interpretation reports was 30.8% (52/169 patients), of whom 17.3% (9/52 patients) were referred to the endocrinology department for further careful examination. Incidental findings in the thyroid gland were relatively common on CT images of the oral and maxillofacial region. Oral radiologists tend to focus specifically on the oral and maxillofacial region during diagnosis on oral and maxillofacial CT images, but should pay the same careful attention to observe adjacent regions, such as the thyroid gland.

DOI： 10.3892/ol.2020.11298

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Language：Japanese   Publisher：(NPO)日本歯科放射線学会  

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Language：Japanese   Publisher：(NPO)日本口腔科学会  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

To evaluate the feasibility of using ultrasound-obtained tumor depth (TD) and margin shape (MS) to predict the prognosis of tongue cancer.
Fifty-two Japanese patients with tongue cancer who underwent ultrasound examination between 2007 and 2012 were retrospectively evaluated. TD was measured at the deepest portion of the tumor. MS was classified as "pressure," "wedge-shaped," or "permeated." Prognosis was assessed by local recurrence, lymph node metastasis, and overall survival rate. We classified the patients into a good prognosis group and poor prognosis group. Relationships among TD, MS, and patient prognosis were evaluated using Spearman rank correlation. A regression formula to predict prognosis using TD and MS was derived.
The correlation between TD and MS was significant (Spearman rank correlation rho = 0.552, p &lt; 0.01). Using a structure matrix, we identified the contribution of both predictors from an ultrasound image. The contribution of TD was 0.796, while that of MS was better at 0.906. The prognosis could be predicted using the following regression formula: , where D prognosis (risk probability), x = TD (mm), and y = MS (grade). The average value for good risk probability was -0.254 (standard deviation, 0.962), while that for poor risk probability was 0.566 (standard deviation, 1.08) (p &lt; 0.05). The cut-off value for classifying cases was -0.00169. Using the formula above, 73.1 % of patients in the poor prognosis group were correctly classified.
MS and TD are useful predictors of tongue cancer prognosis.

DOI： 10.1007/s11282-016-0251-y

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Language：Japanese   Publisher：(一社)日本口腔腫瘍学会  

舌対称性脂肪腫症(SLT)は、成熟した脂肪組織が両側の舌筋内へ浸潤性増殖する疾患と定義される。今回われわれは、巨舌を呈したSLTの症例を経験したので、文献的考察を加えて報告する。患者は、両側舌縁部に無痛性で弾性軟、多発性の腫瘤を認めた71歳の男性である。舌縁部の外向性腫瘤により、患者の舌幅は下顎の歯列弓幅よりも広く、いわゆる巨舌を呈していた。両側舌縁部の腫瘤は、MRIのT1およびT2強調画像で高信号、T2脂肪抑制像で信号低下を示した。生検組織の病理組織学的診断は脂肪腫であった。病変が対称性はないものの、両側の舌縁部にあることから、SLTと診断した。慢性心房細動に対して抗凝固薬を内服しており、術後の出血および腫脹による気道閉塞が懸念されたため、左右2回に分けて全身麻酔下に腫瘍減量術を行った。切除物の病理組織検査では、成熟した脂肪組織が舌筋組織内へ浸潤性増殖している所見がみられ、病理組織学的診断はSLTであった。術後2年経過したが、増大所見は認めない。(著者抄録)

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This study aimed at clarifying whether we can differentiate dentigerous cysts with calcified substances from other odontogenic tumors that include calcification and the crown of an unerupted tooth by CT findings.
We retrospectively selected histopathologically confirmed cases that included calcified substances and the crown of an unerupted tooth inside. There were 22 cases with eight pathological categories. Besides seven odontogenic tumors, we included dentigerous cysts, which were usually recognized without calcification within the lesions. We divided the cases into two groups: 14 cases of odontogenic tumors and 8 cases of dentigerous cysts. Cases were analyzed for various CT findings such as continuity with the alveolar crest, bone sclerosis around the lesion, and sizes and shapes of high CT value substances, as well as demographic factors. Comparisons between the groups for each analytical factor were performed.
Dentigerous cysts with dystrophic calcification showed unique CT findings such as bone sclerosis around the lesion, continuity with the alveolar crest, and small scattered calcified substances near the crown of an unerupted tooth, compared with typical dentigerous cysts and other odontogenic tumors. On the other hand, odontogenic tumors showed various patterns in the location and distribution of high CT value substances, and we could only differentiate odontoma using its very high CT values.
Although the patterns of calcification were not the main characteristic findings, it may be possible to differentiate dentigerous cysts with dystrophic calcification from odontogenic tumors by their other characteristic CT findings, and unnecessary extensive surgery can also be avoided.

DOI： 10.1007/s11282-014-0173-5

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BACKGROUND: Squamous cell carcinoma (SCC) as the malignant component of carcinoma ex pleomorphic adenoma (CXPA) occurring in upper lip is rare. CASE REPORT: A 55-year-old male patient presented with an asymptomatic mass of the upper lip that had noticed 8 years previously. The mass was clinically suspected to be a benign salivary gland tumor based on palpation and magnetic resonance imaging findings. A needle biopsy was then carried out, and the pathological diagnosis was pleomorphic adenoma. The tumor was removed under general anesthesia. Histopathological examination revealed well-demarcated tumor tissues showing typical histologic features of pleomorphic adenoma. However, SCC tissue with several mitotic figures was found in the central area of the tumor tissue. The tumor was finally diagnosed as CXPA. There was no evidence of recurrence or metastasis 6 years postoperatively. CONCLUSION: This is the first report of CXPA of the upper lip with an unusual malignant component of SCC.

DOI： 10.1186/1477-7819-11-234

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Publishing type：Research paper (scientific journal)  

Background: Squamous cell carcinoma (SCC) as the malignant component of carcinoma ex pleomorphic adenoma (CXPA) occurring in upper lip is rare.Case report: A 55-year-old male patient presented with an asymptomatic mass of the upper lip that had noticed 8 years previously. The mass was clinically suspected to be a benign salivary gland tumor based on palpation and magnetic resonance imaging findings. A needle biopsy was then carried out, and the pathological diagnosis was pleomorphic adenoma. The tumor was removed under general anesthesia. Histopathological examination revealed well-demarcated tumor tissues showing typical histologic features of pleomorphic adenoma. However, SCC tissue with several mitotic figures was found in the central area of the tumor tissue. The tumor was finally diagnosed as CXPA. There was no evidence of recurrence or metastasis 6 years postoperatively.Conclusion: This is the first report of CXPA of the upper lip with an unusual malignant component of SCC. © 2013 Mitate et al.; licensee BioMed Central Ltd.

DOI： 10.1186/1477-7819-11-234

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Language：Japanese   Publisher：(一社)日本口腔腫瘍学会  

腺扁平上皮癌は口腔領域ではまれな悪性腫瘍である。われわれは下顎歯肉腺扁平上皮癌の1例を経験した。症例は74歳男性。2009年1月初旬、左側下顎歯肉の疼痛と摂食障害を主訴に当科初診。初診時、左側下顎歯肉に55×25mm、弾性軟、暗紫色で易出血性の腫瘤を認めた。また左側オトガイ部に知覚鈍麻を認めた。CT画像では下顎管に達する骨吸収を認めた。頸部超音波検査で2個の左側顎下リンパ節に転移が疑われた。生検組織では扁平上皮癌の要素と、ジアスターゼ処理PAS染色にて粘液産生細胞を認める腺癌要素が見られた。以上より、左側下顎歯肉腺扁平上皮癌(T4N2bM0)と診断した。既往の間質性肺炎の状況から手術が困難であることと本人の希望により、根治的放射線化学療法としてUFT内服と放射線外照射を施行した。その後、両肺野、腹部と腋下部の皮膚に多発遠隔転移を認めた。4月末日呼吸状態悪化により永眠した。(著者抄録)

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2012&ichushi_jid=J02382&link_issn=&doc_id=20120619340005&doc_link_id=%2Fdy8ortum%2F2012%2F002402%2F006%2F0055-0061%26dl%3D0&url=http%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fdy8ortum%2F2012%2F002402%2F006%2F0055-0061%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

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Objectives To evaluate four digital intraoral radiographic systems using perceptibility curves (PCs) in a grayscale domain and to clarify the usefulness of this new method.
Methods Four systems were evaluated, namely the CDR, Dixel, Digora, and Digora Optime. An aluminum phantom with 12 steps was radiographed using all four systems. The mean gray values and their standard deviations were measured for each step as well as the background of the images for each device. The minimum perceptible gray level differences at a given exposure were calculated from the mean gray values and standard deviations, and a PC in the grayscale domain was constructed at each exposure for all devices. The area under the PC was assumed to be the perceptible contrast information at that exposure for each system. By combining the PCs at all exposures for each system, the maximum perceptible contrast information in each system was calculated. The correlation between the perceptible contrast information and the number of perceptible holes by observers at each exposure was examined for all four digital systems.
Results The Dixel and Digora Optime showed similar PCs, and their minimum perceptible gray level differences were the smallest among the systems. The correlation between the number of perceptible holes and the areas under the PCs at each exposure for the four systems was relatively high (r = 0.92).
Conclusions The areas under the PCs in a grayscale domain were highly correlated with observer performance. This method can be used to evaluate the image quality of new digital systems.

DOI： 10.1007/s11282-011-0068-7

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To evaluate whether a pharmacokinetic analysis is useful for both predicting and monitoring the response to chemoradiotherapy (CRT) in oral cancer.
Patients with oral squamous cell carcinoma treated with preoperative CRT and surgery were enrolled. They underwent dynamic contrast-enhanced MRI before (n = 23), and after CRT (n = 20). We estimated four parameters: arrival time of contrast medium (TA), exchange rate constant from the extracellular extravascular space (EES) to plasma (k(ep)), elimination of contrast medium from the central compartment (k(el)) and an amplitude scaling constant (AH) using the Brix model. The histological evaluation of the effects of CRT was performed according to Ohboshi and Shimosato's classification. We analysed the correlation between the parameters and the histological evaluation.
The pre-CRT AH between the responders and non-responders was significantly different (P = 0.046), however, the three parameters (TA, K-ep, K-el) were not significantly different among the groups (P = 0.76, P = 0.60, P = 0.09). As AH decreased, the tumour response improved. The change in the AH between the pre- and post-CRT of responders was significantly higher than that of non-responders (P = 0.043).
The AH, which is affected by the ratio of the EES, was an important parameter for predicting and monitoring the tumour response to CRT.

DOI： 10.1007/s00330-011-2102-x

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Language：Japanese   Publisher：Japanese Society of Oral and Maxillofacial Surgeons  

Osteoporotic bone marrow defect （OBMD） is a rare benign jaw lesion consisting of hematopoietic bone marrow, which results in a focal bone defect. The present report describes a case of OBMD in the mandibular molar region of a 53 year-old-woman. A panoramic radiograph showed the presence of an undefined round,thumb-sized radiolucent lesion in the lower left first molar region. The density inside of the lesion was −37.7 Hounsfield units on CT scanning, suggesting fat tissue. The biopsy specimens revealed fat tissue with thin bone trabeculae and hematopoietic cell infiltration. The clinical course has been uneventful without any treatment for 4 years.

DOI： 10.5794/jjoms.57.264

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Other Link： https://jlc.jst.go.jp/DN/JALC/00370585220?from=CiNii

Language：Japanese   Publisher：Japanese Society of Oral Oncology  

The histopathological diagnosis of salivary gland tumors is sometimes difficult, because the tumors have various histologic patterns and manifold tissue components coexist in a histologic pattern. Therefore, the differential imaging diagnosis of a benign and malignant tumor in the salivary gland is also sometimes difficult.<br>A salivary gland lesion in which the border is slightly unclear is sometimes a malignant tumor, even though the borderline looks almost clear on the images. Therefore, in the imaging diagnosis of salivary gland tumors, the clearness of the boundary on the images is very important and its cautious interpretation is essential; the clearness should be judged not by CT but by ultrasonography and MRI. Moreover, the CT and MRI images should be observed by optimal indication on a DICOM Viewer, if possible.<br>Regarding major salivary gland tumors: over 70% of parotid gland tumors are benign, 40% of submandibular gland tumors are malignant, and 80% of sublingual tumors are malignant. These figures are important when interpreting diagnostic images of major salivary gland tumors. A parotid gland tumor in which the border is not always clear should be suspected as malignant. A lesion that is confirmed as a sublingual gland tumor on diagnostic images should be diagnosed as a malignant tumor.<br>Concerning minor salivary gland tumors: when the tumor is small, a borderline is often clear even though the tumor is malignant. Hence, imaging findings of a lesion with a clear boundary are not evidence of a benign tumor in the minor salivary gland. In malignant salivary gland tumors of the palatal region, particular attention should be paid to weak bone invasion, which cannot be detected on imaging findings. In the lip and buccal region, ultrasonography is the most effective imaging modality. It is necessary to remember that mucoepidermoid carcinoma occurs also in the jawbones.

DOI： 10.5843/jsot.23.59

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BACKGROUND: Persistent muscle contractions during clenching are considered to be one reason for temporomandibular disorders. However, no report has evaluated the effect of clenching on the masticatory muscles, as measured by magnetic resonance imaging (MRI). PURPOSE: To investigate whether clenching has an effect on either T(2) or the coefficients for diffusion of the masseter muscles (MM), and to evaluate the effect of the distribution of bite force on such indices. MATERIAL AND METHODS: Twenty-three subjects were examined. Bite force was measured by a pressure-sensitive sheet, and the force of the right and the left sides was calculated. MRI was used to evaluate T(2), the apparent diffusion coefficient (ADC), and the primary (lambda(1)), secondary (lambda(2)), and tertiary eigenvalues (lambda(3)). These indices on the stronger side of the bite force were compared to those on the weaker side. Thereafter, the indices were compared between at rest and during clenching. RESULTS: There was no significant difference in any of the indices (T(2), ADC, lambda(1), lambda(2), and lambda(3)) between the side of stronger bite force and the side with weaker. T(2) increased by clenching, and the difference was significant in the side with stronger bite force (P = 0.006). ADC, lambda(1), lambda(2), and lambda(3) increased significantly by clenching (P <0.01, P <0.01, P <0.01, and P <0.01, respectively) on both sides. The percentage of change of lambda(2) by clenching was 26.2+/-15.7% on the stronger side and 26.9+/-18.6% on the weaker side, which was significantly greater than either that of lambda(1) or lambda(3). CONCLUSION: The coefficients for diffusion of the MM were sensitive to change by clenching, and lambda(2) was the most sensitive. Moreover, the relative distribution of the bite forces had no effect on any of the indices.

DOI： 10.3109/02841850903280508

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

We performed three quantitative analyses (particle analysis, fractional Brownian motion [fBM] model analysis, two-dimensional [2-D] fractal analysis) of the ultrasonographic (US) images of the salivary gland and evaluated whether the obtained indices correlated with the sialographic stage of Rubin-Holt. Our study included 192 patients suspected of having Sjogren&apos;s syndrome (SS). In 89 patients, sialography demonstrated abnormal findings. Based on a particle analysis, we calculated both the average size of the particles (avg-area) and the area ratio to evaluate the presence of hypoechoic areas and echogenic lines, which are characteristic of SS. According to the fBM model, we calculated the Hurst index of the original image (Hurst-ori) and the background-subtracted image (Hurst-bs) to evaluate the complexity of the pixel value distribution. We also obtained the 2-D fractal dimension (2-D-FD) to evaluate the complexity of the contour lines. We entered these indices of the parotid glands (PG) into a logistic regression analysis and evaluated which indices were useful predictors for detecting all abnormal sialographic stage. Significant differences were observed between the normal and abnormal groups in all five indices of the PG (Mann-Whitney U test) and all five indices were correlated with the Rubin-Holt stage (Spearman&apos;s Rank Correlation Test). As the Rubin-Holt stage became more severe, both the Hurst-ori and 2-D-FD became smaller. Alternatively, the Hurst-bs, avg-area, and area ratio became higher. Three indices (avg-area, area ratio and Hurst-ori) were selected as useful predictors for detecting abnormal sialographic stages. This quantitative analysis system is therefore considered to have potentially useful clinical applications for the detection of abnormal sialographic findings. (E-mail: chikui@rad.dent.kyushu-u.ac.jp) (C) 2009 World Federation for Ultrasound in Medicine & Biology.

DOI： 10.1016/j.ultrasmedbio.2009.03.005

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Language：Japanese   Publisher：(一社)日本口腔腫瘍学会  

われわれは副耳下腺の多形腺腫を経験した。2004年3月、20歳代後半の男性が右側頬部の腫瘤を主訴に来院した。MRI、超音波検査により副耳下腺部の腫瘤の存在を認めた。術前の針生検では多形腺腫が最も疑われたが、確定するにはいたらなかったため、同年9月手術により摘出した。腫瘤は耳下腺から独立して咬筋の外側にあり、顔面神経頬骨枝に囲まれていたが、容易に摘出でき、術後に顔面神経障害は認めなかった。摘出物の病理組織学的診断は多形腺腫であった。(著者抄録)

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2008&ichushi_jid=J02382&link_issn=&doc_id=20081215300008&doc_link_id=%2Fdy8ortum%2F2008%2F002004%2F008%2F0291-0296%26dl%3D0&url=http%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fdy8ortum%2F2008%2F002004%2F008%2F0291-0296%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

Language：Japanese   Publisher：(NPO)日本口腔科学会  

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Language：Japanese   Publisher：(一社)日本口腔腫瘍学会  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：W B SAUNDERS CO-ELSEVIER INC  

DOI： 10.1016/j.jams.2005.11.087

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Language：Japanese   Publisher：(一社)日本口腔腫瘍学会  

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OBJECTIVE: To assess tongue atrophy and long-term functional outcome of mobile tongue cancer patients after interstitial radiotherapy. METHODS: Of 493 patients whose squamous cell carcinoma of the mobile tongue had been treated with low dose rate brachytherapy, there were 57 patients evaluated between July 2002 and April 2004 whose tongue had not been modified by surgical procedures and who had no primary recurrence. The median time from treatment to evaluation was 96 months (range: 9-214 months). Almost all of the patients belonged to the early stage tongue cancer (T1/T2/T3/T4=30:24:3:0), and all had received interstitial radiotherapy with a single-plane implant. To evaluate the deformity of the tongue, we used a grading system that classified the atrophic changes of the tongue into four categories (G0-G3). RESULTS: Thirty-nine patients (70%) showed mild tongue hemiatrophy (G1 or G2) in the irradiated side. However, no patients showed severe atrophy where the tongue cannot be made to protrude beyond the incisors (G3). The length of time after brachytherapy was >72 months and the age of the patients at brachytherapy had the same statistical significance (P=0.0366). As for functional outcome, understandability of speech and a normal diet were preserved for almost all patients. CONCLUSION: The progression of atrophic change in the irradiated tongue occurred over a long term after brachytherapy. However, most patients could maintain their activities of daily life without severe restriction.

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Twenty-seven patients with oral malignant tumours, who underwent neck dissection with preservation of the internal jugular vein (IJV), were studied retrospectively to evaluate patency of the IJV. Twenty-three patients underwent ablative surgery of the primary lesion with neck dissection and 4 underwent neck dissection alone. Three patients received simple closure and skin grafting of the primary lesion, and 20 received reconstruction surgery (4 platysma flaps, 3 radial forearm flaps, 3 lateral upper arm flaps, 2 pectoralis major myocutaneous flaps and 8 rectus abdominis myocutaneous flaps). The maximum and minimum diameters of the IJV as measured on computed tomographic (CT) scans were used to assess patency. The cross-sectional area of the IJV and the ratio of its long axis to short axis (L/S ratio) were calculated. The relation between the change in IJV status and the type of flap used for reconstruction was also examined. Occlusion of the IJV was present in 3.7% of the patients, and 'narrowing' was present in 63.6%. The size of the flap significantly correlated with 'narrowing' of the IJV, suggesting that 'narrowing' was caused mainly by compression due to the flap. © 2005 International Association of Oral and Maxillofacial Surgeons.

DOI： 10.1016/j.ijom.2005.09.004

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BRITISH INST RADIOLOGY  

Objectives: 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.
Methods: 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.
Results: 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 turn thickness of aluminium with acrylic block of 12 mm thickness.
Conclusions: 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.

DOI： 10.1259/dmfr/13550415

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BRITISH INST RADIOLOGY  

Objective: 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.
Materials and methods: 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 A, values from all observers as a function of incident exposure in each system.
Results: 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.
Conclusion: 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.

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Language：Japanese   Publisher：(NPO)日本歯科放射線学会  

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Language：Japanese   Publisher：(NPO)日本口腔科学会  

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Language：Japanese   Publisher：Japanese Society of Oral Oncology  

Imag ineprocedures such as computed tomography (CT), ultrasonography (US) are examined for predicting cervical lymphnode metastasis in head and neck cancer patients. We reviewed the criteria for metastasis and diagnostic accuracy (sensitivity, specificity and accuracy) of these diagnostic procedures in previous reports. We then discussed the efficiency of these diagnostic procedures for predicting cervical metastasis. Furthermore, our criteria and its positive predict value (PPV) and negative predict value (NPV) with CT, B-mode US and power Doppler US, and the methods of CT and US examinations in our department werere ported.<BR>With CT, sensitivity and specificity were 49%-100%, 38%-100%, respectively. With B-mode US, sensitivity and specificity were 58%-95%, 37%-96%, respectively. With Doppler US, sensitivity and specificity were 55%-98%, 77%-100%, respectively. In the results of our study, PPV for predicting metastasis with CT was 91%. PPV for predicting metastasis with B-mode US were 97%. PPV for predicting metastasis with power Doppler US were 87%.

DOI： 10.5843/jsot.16.75

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Other Link： http://search.jamas.or.jp/link/ui/2005078184

Language：Japanese   Publisher：Japanese Stomatological Society  

We developed two types of fine sialendoscope, which could be introduced to the submandibular duct through the opening of sublingual caruncula. One is a sialendoscope of 1.1-mm outer-diameter (POLYDIAGNOST GmbH, Germany) with 6000-pixels optic fibers, and it has a working channel to insert a basket forceps and an irrigation channel. The other is a sialendoscope of 1.2-mm outer-diameter (FiberTech Co., Ltd., Japan) with 1600-pixels optic fibers and a working channel. Using these newly developed sialendoscopy systems and a 1.9F basket forceps (Boston Scientific Corporation, USA), we could successfully remove a sialolith of the submandibular gland of a 9-year-old girl.

DOI： 10.11277/stomatology1952.53.81

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：W.B. Saunders  

DOI： 10.1016/S0278-2391(03)00691-8

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Language：Japanese   Publisher：Biomedical Fuzzy Systems Association  

Although some computer-assisted diagnostic systems have been reported recently, they have not been so much spread in clinical field yet. The principles of fuzzy or neural network are so complicated to the general clinicians and they do not have the skills or techniques, which are necessary to develop the computer-assisted diagnostic system. The authors herein propose the new method, which automatically optimize the system only by setting the simple inferences. Because the method can be utilized with an ordinary application on a standard personal computer, even the users who cannot make programs can develop the system. The method applies the adaptive neuro-fuzzy inference system (ANFIS), which is combined with fuzzy and neural network. In this method, membership functions, which are set temporally at first, can be optimized automatically by back propagation procedure of neural network. Consequently, the performance of the diagnostic system can be improved. The authors describes the outline of the method with the preliminary applied case to the ultrasonographic dignosis.

DOI： 10.24466/jbfsa.5.1_49

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MUNKSGAARD INT PUBL LTD  

Purpose: To evaluate the usefulness of the combination of the two non-invasive modalities US and MR imaging to diagnose masses in the parotid region.
Material and Methods: The US and MR findings of 21 patients with parotid masses were analyzed retrospectively by two radiologists without any clinical or histopathological information. The specific points evaluated were location, shape, margin, internal architecture, and intensity level on both US and MR, posterior echo enhancement on US, and capsule-like lining of the tumor on MR.
Results: The findings concerning the shape and margin on US and MR were in fairly good agreement. Concerning the findings of the internal architecture. US could reveal the minute structures of the tumor while MR demonstrated differences in the signal intensities of histological tissue types of the various tumors. The posterior echo enhancement on US and the capsule-like lining on MR of the tumors were also useful for the diagnosis.
Conclusion: Our results suggest that the combination of US and MR is useful for examining soft tissue masses in the parotid region to make a more accurate diagnosis, and not just differentiate malignant lesions from those which are benign.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Objectives: To define criteria for CT and US in differentiating cervical lymph node metastases in oral squamous cell carcinoma (SCC).
Materials and methods: CT and/or US of 230 metastatic lymph nodes and 228 benign lymph nodes in 147 patients with oral SCC were retrospectively evaluated. The CT and US findings of each lymph node were compared with the histopathological findings. A metastasis was defined on Ci as a lymph node with rim or heterogeneous enhancement, or measuring 10 mm or more in the short axis. regardless of enhancement pattern, and on US as having definite internal echoes. regardless of size, or without definite internal or hilar echoes, but measuring 10 mm or more in the short axis. A lymph node with hilar echoes or a ratio of the long to short axis (L/S ratio, of 3.5 or more was considered benign. A lymph node failing to conform to any of these categories was termed questionable.
Results: The positive predictive value (PPV) for CT was 90.8% and the negative predictive value (NPV) was 70.4%. However, 65.7% of all lymph nodes could not be classified as either metastastic or benign. PPV for US was 96.5% and NPV was 88.1%. 25.5% of all lymph nodes could not be classified as either metastatic or benign.
Conclusions: Despite limitations in detecting metastses, by including a third category 'questionable' our criteria appear clinically more useful than other current methods based on two groups only.

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Language：Japanese   Publisher：Japanese Society for Oral and Maxillofacial Radiology  

Palpation and imaging procedures such as computed tomography (CT), ultrasonography (US), magnetic resonance imaging (MR), radioisotope imaging (RI) and lymphography are examined for predicting cervical lymph node metastasis in head and neck cancer patients. We reviewed the criteria for metastasis and diagnostic accuracy (sensitivity, specificity and accuracy) of these diagnostic procedures in previous reports. We then discussed the efficiency of these diagnostic procedures for predicting cervical metastasis. Furthermore, our criteria and its positive predictive value (PPV) and negative predictive value (NPV) with CT, B-mode US and power Doppler US, and the methods of CT and US examinations in our department were reported. In previous reports, it was reported that sensitivity was 47%-97%, specificity was 38-92%, accuracy was 69-88% with palpation. The diagnostic efficiency of lympography was considered to be low. Now this procedure is not used in diagnosing cervical metastasis. ¹⁸FDG-PET was preformed mainly. Its sensitivity and specificity were 50-93% and 77-100%, respectively. With CT, sensitivity and specificity were 49%-100%, 38%-100%, respectively. With MR, sensitivity and specificity were 47%-100%, 48%-100%, respectively. With B-mode US, sensitivity and specificity were 58%-95%, 37%-96%, respectively. With Doppler US, sensitivity and specificity were 55%-98%, 77%-100%, respectively. In the results of our study, PPV for predicting metastasis with CT was 91%. PPV for predicting metastasis with B-mode US were 97%. PPV for predicting metastasis with power Doppler US were 87%.

DOI： 10.11242/dentalradiology1960.40.109

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Language：English   Publishing type：Research paper (scientific journal)  

OBJECTIVES: This article demonstrates a new method of making a spacer that increases the distance between the mandible and implanted radioactive sources in interstitial brachytherapy for patients with mobile tongue cancer. STUDY DESIGN: Fifty-three patients with mobile tongue cancer underwent interstitial brachytherapy with spacers made by this new technique. RESULTS: Our spacer is not difficult to create or to use. The spacer was made from a plastic splint by using thermoforming techniques and quick self-curing resin, which did not need waxing, wiring, or casting. The surface of the spacer, which comes in contact with the tongue, is smooth because it is covered with tissue-conditioning material. There were no complaints of pain from the patients. Osteoradionecrosis of the mandible developed in only 1 (1.9%) of these patients. CONCLUSIONS: This spacer is simple to make and prevented osteoradionecrosis.

DOI： 10.1016/S1079-2104(00)70134-X

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Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND AND PURPOSE: Because the presence of cervical metastasis is one of the factors influencing the outcome of patients with carcinoma of the head and neck, its early detection is potentially very important. The purpose of this study was to evaluate the characteristic changes of cervical metastasis revealed by sonography during follow-up and to assess an adequate interval for follow-up sonography of the neck among patients with tongue cancer. METHODS: Forty-three of 44 consecutive patients with squamous cell carcinoma of the tongue, who had undergone interstitial brachytherapy, were examined with sonography of the neck during the posttherapeutic follow-up period. RESULTS: Seventeen cervical lymph node metastases were found in 12 of 43 patients during follow-up. Of these 17 cervical metastases, 16 (94.1%) were accurately diagnosed and one (5.9%) was misdiagnosed as nonmetastatic based on sonographic findings. Sonography of the neck performed in seven patients at an interval of less than 1 month since the last follow-up imaging showed 9 (90.0%) of 10 metastases increased by up to 2 mm in short-axis diameter. Five patients who were followed up at an interval of more than 1 month since the last follow-up imaging had seven metastases increase by 3 to 8 mm in short-axis diameter or a change of echogenicity in the internal structure of lymph nodes or both. Pathologic examinations showed extranodal spread in 3 (4.2.9%) of these 7 metastases. CONCLUSION: Changes both in size and internal echogenicity can occur as quickly as 2 to 4 weeks between sonographic examinations. Therefore, in high-risk patients, or in those with suspicious sonographic findings, short-interval follow-up sonographic examinations are recommended at least during the first posttherapeutic year. Our findings suggest that follow-up sonography of the neck should be performed monthly, at least during the first posttherapeutic year.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MOSBY-YEAR BOOK INC  

Objective, The purpose of this study was to compare 2 film systems and several digital intraoral systems with regard to visual image quality through use of a test phantom developed for this purpose.
Study design. The detectors used for digital imaging were as follows: Computed Dental Radiography (CDR), Digora, Dixel, and Sens-A-Ray without scintillator layer Two types of digital images were prepared for the observer performance test: one with original gray scales and another with contrast enhancement. Images with and without enhancement from the 4 systems were displayed to 7 observers. The change in the average number of perceptible holes was plotted against exposure, and modified perceptibility curves were created and compared with curves for the film systems. The exposure level at which the maximum number of holes was perceived was defined to be optimum. The optimum exposure levels were determined for each digital system and compared with that of the film systems. At the optimum exposure, the average maximum numbers of perceptible holes in each digital system with and without contrast enhancement were compared with the maximum numbers for the film systems. The minimum exposure levels were determined to be those at which the number of perceptible holes exceeded the number for film, and the possibility of exposure reduction was evaluated.
Results. All digital systems except the Digora system showed lower optimum exposures than E-speed film. In all digital images without enhancement, however, the maximum number of perceptible holes was significantly lower than that for the film systems at that exposure. With contrast enhancement, all digital systems except the Sens-A-Ray system showed visibility superior to that of the film systems. With the CDR, Digora, and Dixel systems, exposures could be further reduced by a considerable amount, with greater retention of information than was associated with film.
Conclusions. Our results strongly suggest that digital systems, if properly used, can exceed film systems in the detection of smalt mass changes.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MOSBY-YEAR BOOK INC  

Objective. The purpose of this study was to describe and validate an image-quality phantom to be used in dental radiography for comparison of film and digitally acquired images.
Study design. An aluminum block of 12 steps, with 7 holes in each step, was covered by acrylic blocks. This phantom was radiographed with Kodak Ultra-speed and Ektaspeed Plus films at 70, 65, and 60 kVp with the whole exposure range available. All together, 50 dental films were randomly sequenced and presented to 7 observers. The average number of perceptible holes from all steps was plotted against exposure for each tube voltage and film type, generating a modified perceptibility curve. The tentative optimum exposure revel was determined from perceptibility curves in each experimental condition and compared with that determined by means of the standard aluminum step-wedge and the preset time of the x-ray machine. The density range of this phantom at the optimum exposure was compared with that of clinical dental radiographs. Validity of the phantom was evaluated according to the optimum exposure level from the modified perceptibility curves and the overall density range. Finally, the average maximum numbers of perceptible holes at the tentative optimum exposure level were compared for each tube voltage and film type. The statistical test used was a 2-way factorial analysis of variance.
Results, The exposure at the perceptibility curve peak approximated that obtained by means of the standard aluminum step-wedge and the time preset by the manufacturer. The overall density range at the perceptibility curve peak covered the clinical density range for each tube voltage and film type. There were no statistically significant differences between firm types or among tube voltages.
Conclusions. The x-ray attenuation range for this phantom seemed to approximate clinical conditions. In addition, differences in image quality could be quantitatively evaluated by means of the number of the holes seen in the phantom.

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Language：English   Publisher：Biomedical Fuzzy Systems Association  

Recently the digital dental imaging system (DDIS) has been developed and its use has spread widely. Although it has several advantages, the image quality is not better than that of conventional dental radiographs. Particularly, the density distributions of DDIS images are often insufficient and inadequate. Therefore, the authors considered the density optimization of DDIS images. For this aim, we applied a fuzzy c-means clustering algorithm because the pattern of DDIS images has an extensive variety. Using our method, the denstity distribution of most DDIS images can be improved appropriately. In addition, this method provides a dose reduction for the patients. Consequently, 38.3% of the absorbed dose was decreased.

DOI： 10.24466/ijbschs.5.1_33

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Language：Japanese   Publisher：Biomedical Fuzzy Systems Association  

The authors have developed a computer-assisted diagnostic system for ultrasonograpny using fuzzy reasoning. In this system, we adopted the centroid method of defuzzification for fuzzy reasoning. There have been reported, however, several methods for defuzzidication. Although the computer-assisted diagnosis obtained from fuzzy reasoning might varies with different defuzzification methods, there were few literatures concerning this subject. Hence, the authors considered other defuzzidcation methods;centroid(Cent), bisector(Bis), middle of maximum(MOM), largest of maximum(LOM)and smallest of maximum(SOM)methods. Diagnostic accuracy, sensivity and specificity acquired from these defuzzifications were compared each other. Consequently, Cent, Bis and MOM are adequate procedures. On the other hand, diagnostic accuracy acquired by LOM or SOM is worse than other procedures. However, sensitivity of LOM and specificity of SOM are better than others. Therefore, these methods are useful when sensitivity or specificity is clinically important.

DOI： 10.24466/jbfsa.1.1_1_2

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Language：Japanese   Publisher：Japanese Society of Oral Oncology  

Purpose: The purposes of this study were to show our protocol of diagnostic imaging using CT and ultrasonography and to evaluate the diagnostic accuracy for cervical lymph node metastasis in oral squamous cell carcinoma.<BR>Material and Methods: CT and/or ultrasonography of 147 patients were evaluated retrospectively. Lymph nodes were confirmed pathologically whether metastasis or non-metastasis. The detection ratio, enhanced pattern and short diameter of lymphadenopathy were analyzed on CT. Internal echoes such as hilus and parenchymal echoes, the short diameter, long diameter and the long to short diameter ratio (S/L ratio) were evaluated on ultrasonography.<BR>Results: Ten percent of lymphadenopathy, which was confirmed pathologically as metastasis, was not found on CT. Heterogeneous or rim-enhanced pattern was presented in 50.9% of metastasis and only 4.5% of non-metastasis cases on CT. Strong parenchymal echo pattern was shown in 56.9% of metastasis cases. On the other hand, 66.5% of non-metastasis cases showed a hilus but strong parenchymal echoes. Under the circumstances where lymph nodes had neither hilus nor strong parenchymal echoes, but were 10 mm or more in short diameter, 27.4% were shown in metastasis and only 3.0% in non-metastasis cases. Futhermore, under the circumstances where lymph nodes had neither hilus nor strong parenchymal echoes, but were 3.5 or more in S/L ratio, only 1.5% were shown in metastasis and 13.5% in non-metastasis cases.<BR>Conclusion: On basis of the results of this study, it was suggested that criteria for cervical metastasis using CT and ultrasonography in which"Questionable only on diagnostic imagings"be included. It was considered that this criteria is clinically useful.

DOI： 10.5843/jsot.10.288

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Language：Japanese   Publisher：Biomedical Fuzzy Systems Association  

Aim of this study is to consider the accuracy in differentiating between benign odontogenic tumor (ameloblastoma) and cyst (odontogenic keratocyst) on CT image using neural network. In order to determine the weights and the biases of our neural network system, 53 cases (29 ameloblastomas, and 24 odontogenic keratocysts) were used for the learning mode. Another 20 cases (6 ameloblastomas, and 14 odontogenic keratocysts) were evaluated for determining the accuracy in the test mode. The result showed that the diagnostic accuracy was 85 %. It was suggested that the neural network is useful for differentiating these lesions.

DOI： 10.24466/pacbfsa.11.0_27

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Language：Japanese   Publisher：Biomedical Fuzzy Systems Association  

Recently the digital dental imaging system (DDIS) has been developed and spread widely. The density distribution of DDIS images, however, are insufficient or inadequate. Therefore, the authors considered the density optimization of DDIS images, and applied the fuzzy reasoning and fuzzy c-means clustering algorithm for this purpose. According to our method, density distribution of most DDIS images could be improved appropriately. Moreover, this method could be applied to the dose reduction of the patients. Consequently, it was suggested that the absorbed dose could be decreased 38.3%.

DOI： 10.24466/pacbfsa.11.0_29

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Language：Japanese   Publisher：Biomedical Fuzzy Systems Association  

The digital dental imaging system (DDIS) has been developed and spread widely in recent years. The images of DDIS, however, aren't always so good, because of insufficient density distribution. Therefore, it seems that DDIS requires density optimization in an appropriate way. The authors applied the fuzzy reasoning and fuzzy c-means clustering algorithm for this purpose. According to our method, density distribution of most DDIS images could be improved better than the conventional histogram equalization method.

DOI： 10.24466/pacbfsa.10.0_75

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Mosby Inc.  

Purpose. The purpose of this study was to analyze the effects of lesion site and epithelial keratinization on the morphologic characteristics of odontogenic cysts and clarify determinate factors for cyst morphology. Material and methods. Computed tomographic images of 92 odontogenic cysts were analyzed: 31 primordial, 31 dentigerous and 30 radicular. Thirty-four cysts were located in the maxilla (6 primordial, 10 dentigerous, and 18 radicular) and 58 in the mandible (25 primordial, 21 dentigerous, and 12 radicular). Histologically, 31 cysts showed epithelial keratinization (18 primordial and 13 dentigerous). No keratinization was seen in radicular cysts. The morphologic features of cysts were assessed by measuring long length parallel to dental arch and short length vertical to it and calculating the long/short ratio. In addition, the computed tomography pattern of the cyst was classified into unilocular, lobulated, and multilocular patterns. Appearance of the sclerotic rim and surrounding cortex were classified into three and four patterns respectively to evaluate the developmental features of the cyst. Results. As a whole, the long length of the primordial cysts was statistically larger than the other two cyst groups and resulted in a larger long/short ratio. Statistical differences of CT pattern were also seen among cyst groups. There was no preference in any cyst group for the appearance of the sclerotic rim and cortex. There were statistical differences between maxilla and mandible in short axis and long/short ratio. The maxillary cysts generally showed round shapes irrespective of their histologic characteristics. A multilocular pattern was more frequent in the keratinized group of mandibular primordial cysts. In dentigerous cysts, a multilocular pattern was seen only in the keratinized group and the long/short ratio was statistically larger
cyst shape was elliptical along the long axis. Conclusion. Our results demonstrated morphologic differences of odontogenic cysts caused by lesion site and keratinization. The dentigerous cyst with predominant keratinization should be included in the primordial cyst (odontogenic keratocyst) group.

DOI： 10.1016/S1079-2104(97)90325-5

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Language：English   Publisher：MOSBY-ELSEVIER  

Objective. The aim was to investigate the diagnostic imaging characteristics of Mikulicz disease (MD), especially sonographic ones, and to clarify the differences between them and those in Sjogren syndrome (SS), based on new criteria of MD.
Study design. The sonographic and sialographic images, as well as clinical, histopathologic, and serologic findings of 9 patients satisfying the new criteria of MD were analyzed and compared with those in SS.
Results. All swollen submandibular glands showed bilateral nodal hypoechoic areas with high vascularization on sonograms and a parenchymal defect on sialograms, whereas parotid glands showed normal or slight change on both images. Nodal areas in submandibular gland sonograms were unclear on computerized tomography and on magnetic resonance imaging, but showed accumulation on gallium scintigraphy.
Conclusion. Mikulicz disease showed a high rate of bilateral nodal change in submandibular glands, which was completely different from SS. For detection and follow-up of these changes, sonography may be the best imaging modality. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 108: 105-113)

DOI： 10.1016/j.tripleo.2009.02.032

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Language：English   Publisher：INT INST ANTICANCER RESEARCH  

Background: Brachytherapy for patients with early tongue cancer is an accepted method of treatment. Patients and Methods: The records of 409 patients with T1/2N0M0 tongue cancer treated with brachytherapy between 1978 and 2004 were reviewed. Results: The overall and disease-free 5-year survival rates were 82.3% and 64.6% for patients with T1 disease, and 72.2% and 56.0% for patients with T2 disease, respectively. The 5-year nodal metastasis-free survival rates for patients treated between 1978 and 1986, 1987 and 1996, and 1997 and 2004 were 64.8%, 74.8% and 81.3% for patients with T1 disease (p = 0.22), and 47.4%, 70.4% and 76.4% for patients with T2 disease (p = 0.0011), respectively. The 5-year local recurrence-free survival rates for patients treated between 1978 and 1986, 1987 and 1996, and 1997 and 2004 were 91.0%, 84.0% and 96.9% for patients with T1 disease (p = 0.31), and 87.6%, 83.3% and 85.8% for patients with T2 disease (p = 0. 90), respectively. Conclusion: The incidence rate of nodal metastasis in patients with early tongue cancer improved over the 25-year period studied, while the local recurrence-free survival rates remained stable.

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Language：English   Publisher：OXFORD UNIV PRESS  

Purpose: To assess the efficacy of neck dissection (ND) without glossectomy (GL) for late nodal metastases without local recurrence after brachytherapy for N0 tongue cancer.
Materials and methods: Among 396 patients with N0 tongue cancer treated with brachytherapy, a retrospective analysis was performed in 111 patients who were clinically diagnosed as having nodal metastases without local recurrence and whose neck lymph nodes turned out to be pathologically positive after salvage surgery. One hundred and five patients had undergone only ND (the ND group), six patients had undergone ND with GL (the ND+GL group).
Results: The 5 year disease-free and cause-specific survival rates after salvage therapy for the 111 patients included in this study were 58.1 and 61.9%, respectively. In the ND group, there were only nine patients who had local recurrence after ND. In addition, only six patients (5.7%) had a local recurrence within 2 years in the ND group. Sixty-three patients were free of disease after ND, 31 patients had regional or distant metastases without local recurrence and two patients had progressive disease at ND. In the ND+GL group, four patients were alive without disease and two died from regional or distant metastases. None of the patients in the ND+GL group were found to have malignant tissue in the pathological findings from the excised tongue.
Conclusion: GL should be avoided or suspended when the clinical evaluation had revealed cervical failure without apparent local recurrence in the mobile tongue cancer patients after initial brachytherapy.

DOI： 10.1093/jjco/hyi218

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Purpose: The purpose was to illustrate the sonographic changes of tongue cancer after radical radiotherapy. Materials and methods: In 24 patients with tongue cancer treated by interstitial brachytherapy (BRT) (uneventful recovery n=16, recurrence n=5, severe soft tissue complication n=3), follow-up examination were performed and both the margin and the vascular pattern were retrospectively assessed. We basically performed US examination at least once every 3 months after BRT within 1 year during follow-up period. Results: In the healing process, intraoral sonography shows an unclear margin immediately after brachytherapy and a transient increase of the vascularity lasted within 6 months after BRT, followed by a decrease in the vascularity. The large difference in echogenicity between the primary site and the surrounding tissue and the increased difference suggested the possibility of either radiation ulceration or recurrence. Conclusion: Intraoral sonography could depict the sequence changes of the tongue after BRT, and it was thus useful to confirm the clinical findings of either radiation ulcers or recurrence. © 2004 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.ejrad.2004.01.012

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Language：English   Publisher：BRITISH INST RADIOLOGY  

Objectives: To construct perceptibility curves (PCs) for given calibration settings in order to define psychophysical properties of the Digora storage phosphor system and to evaluate the effects of automatic exposure correction (AEC) on the PCs.
Methods: The Digora system was calibrated at two exposures, 80 muC kg(-1) (high calibration) and 40 RC kg(-1) (low calibration). Since the grey levels displayed in the radiographs are adjusted by AEC, dose-response functions at high calibration were obtained using AEC on and off modes. The dose-response function at low calibration was obtained with AEC off. The PC at each experimental setting was calculated using known physical parameters of the system and the performance of the average observer used in a previous study. In addition, PCs were also constructed using transmitted radiation flux behind the test object calculated from the attenuation coefficient in order to study observer and system performance. PCs obtained under these conditions were compared.
Results: The PC using calculated transmitted radiation flux behind the test object showed a wide plateau at the peak owing to AEC, while the PC obtained by a modified approach showed a higher but narrower peak. There were no differences between the two PCs using AEC on and off modes when the PCs were constructed using a modified approach. There were no differences between the two PCs obtained at high and low calibration settings or between the three PCs obtained with AEC on except for the position along the exposure axis.
Conclusions: Psychophysical properties of the Digora system may be determined if we employ registered exposures from a dose-response function with AEC off under a given calibration setting. Under these circumstances the shape and height of the PCs will be unchanged irrespective of the AEC mode.

DOI： 10.1259/dmfr/25806978

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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.

DOI： 10.1067/moe.2003.134

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Authorship：Lead author   Language：English  

DOI： 10.1007/BF02493239

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Objective: To clarify the diagnostic accuracy of CT in detecting the extent of tumor invasion into the surrounding soft tissues by squamous cell carcinoma of the mandibular gingiva.<BR>Method: Axial CT scans of 77 patients with carcinoma of the mandibular gingiva were evaluated by three Oral and maxillof acial radiologists for the tumor invasion into the surrounding soft tissues. All patients underwent excision of the tumor in Kyushu University Dental Hospital from 1992 to 1999, and the presence and the extent of tumor invasion were confirmed by the macroscopic or histopahological findings following surgery. The observers rated their level of confidence for the presence of tumor invasion into genioglossus muscle (GGM), mylohyoid muscle (MHM), intrinsic lingual muscles (ILM), internal pterygoid muscle (IPM), masseter muscle (MM), labiobuccal tissues (LBT), and platysma muscle (PM) on the following five-point scale : 1, negative ; 2, probably negative ; 3, unsure ; 4, probably positive; 5, positive. The mean ROC curve area (Az) of each observer for tumor invasion into each tissue was obtained, and used as the index of diagnostic accuracy.<BR>Results : The mean Az values for the detection of tumor invasion on CT was 0.86 for GGM and IPM, 0.82 for MHM, 0.80 for MM, 0.76 for ILM, 0.71 for LBT, and 0.65 for PM.<BR>Conclusion : We should carefully interpret the tumor invasion into ILM, LBT and PM on CT images referring to the various clinical information, including inspection or palpation.

DOI： 10.5843/jsot.13.Suppliment_253

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Objectives: To construct Perceptibility Curves (PCs) for contrast-enhanced digital intraoral radiographs
Methods: Radiographs of a test object having holes of increasing depths were exposed using three digital systems, the CDR (Schick Technologies, Long Island, NY, USA), the Dixel (J Morita MFG, Kyoto, Japan) and the Sens-A-Ray (Regam Medical Systems, Sundsvall, Sweden). The radiographs were contrast-enhanced and PCs constructed in the conventional way using 10 observers. Predicted PCs were calculated and compared with observer data.
Results: The PCs showed that contrast enhancement is effective for the perception of small contrast details, especially in the low exposure range. Predicted PCs demonstrated excellent agreement with observer data.
Conclusions: Contrast enhancement should be advantageous in digital radiography. The effects of contrast enhancement on PCs may be predicted without previous knowledge of observer performance.

DOI： 10.1038/sj.dmfr.4600607

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Other Link： http://search.jamas.or.jp/link/ui/2001123650

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Language：English   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：MOSBY-YEAR BOOK INC  

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 T-2-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 T-1-weighted images.
Conclusions. Although contrast-enhanced T-1-weighted imaging may not improve delineation of masses in all cases, it can be used to differentiate between deep hemangiomas and lymphangiomas.

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Objectives: To determine technical properties of a direct digital intra-oral radiographic system, the Dixel(R)(J Morita Corporation, Kyoto, Japan).
Methods: A dose response function and the dark current were calculated from two series of exposures to a homogeneous radiation field. The line spread function (LSF) and the modulation transfer function (MTF) were determined from radiographs of an edge. The noise power spectrum (NPS) was determined at three exposures from radiographs exposed to homogeneous radiation fields. Noise equivalent quanta (NEQ) were calculated from the one-dimensional NPS and the MTF. The detective quantum efficiency (DQE) was determined from the NEQ and a representative value of the photon fluence. Signal-to-noise ratios (SNR) were calculated from the NEQs and different signal contrasts.
Results: The dose response function demonstrated a slight curvature. There was no effect of the dark current. NPS ranged from 10(-5)-10(-7) mm(2) depending on exposure and frequency. At a peak of about 2 cycles/mm the DQE is on an average about 30 per cent. SNRs are favorable.
Conclusion: The technical properties found in this study indicate that the Dixel(R)system is suitable for intra-oral dental radiography.

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Objectives: To derive and test a method to predict Perceptibility Curves (PCs) for direct digital intraoral radiographic systems.
Methods: A test object was used to determine the performance of an average observer with respect to the threshold contrast and internal noise of the human visual system. These data were combined with system parameters to predict PCs mathematically.
Results: Data on the performance of an average observer could be defined to obtain values of the effective threshold contrast as a function of background gray level. This function combined with the gamma-value of the system predicted PCs that agreed well with PCs obtained in the conventional way.
Conclusion: It is possible to predict PCs from a limited number of system parameters together with predetermined data on an average observer.

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DOI： 10.5843/jsot.11.135

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DOI： 10.5843/jsot.11.135

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Language：Japanese   Publisher：(NPO)日本口腔科学会  

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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 weil-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.

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Language：English   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：MOSBY-YEAR BOOK INC  

The purpose of this study is to evaluate the usefulness of endoscopy as a procedure for the diagnosis of submandibular gland duct disorders. Endoscopy of the submandibular glands was performed on 12 patients with symptoms of obstructive sialoadenitis to identify the cause of obstruction. The endoscopic findings were then compared to those of diagnostic procedures such as conventional radiography, sialography, and ultrasonography. Six normal subjects also underwent endoscopy to better understand the normal findings of the duct system. Endoscopy demonstrated salivary gland calculus in 5 of 12 patients, which was revealed as filling defects on sialograms and as strongly echogenic structures on ultrasonograms in 4 of the patients. Endoscopy revealed secretion plugs, secretion plaques, and/or stenosis, which could not be seen by any other diagnostic procedures in 5 patients, as the cause of recurrent swelling in all 7 patients not demonstrating sialolith. Abnormal findings of the duct wall such as vasodilatation, fibrosis, edema, or erythema were seen in four patients, three of whom exhibited dilatation of the duct system on sialograms. In four patients, a decreasing internal echo level of the gland was seen on ultrasonograms. Our initial results for submandibular gland duct endoscopy thus appear to be promising.

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DOI： 10.11242/dentalradiology1960.37.211

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DOI： 10.11242/dentalradiology1960.37.211

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