Faculty Profiles - KAWAZU Toshiyuki

Papers - KAWAZU Toshiyuki

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中山英二, 岡村和俊, 大山順子, 川野真太郎, 小林家吉, 清島保, 筑井徹, 河津俊幸, 吉浦一紀, 中村誠司, 白砂兼光

日本口腔腫瘍学会誌 19 ( 4 ) 232 - 232 2007.12

A newly developed interventional sialendoscope for a completely nonsurgical sialolithectomy using intracorpereal electrohydraulic lithotripsy Reviewed

Eiji Nakayama, Kazutoshi Okamura, Takeshi Mitsuyasu, Toshiyuki Kawazu, Norifumi Nakamura, Seiji Nakamura, Kazunori Yoshiura

JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY 65 ( 7 ) 1402 - 1405 2007.7

体内電気水圧衝撃波を利用した非観血的内視鏡下唾石破砕摘出システムの開発

中山英二, 岡村和俊, 光安岳志, 河津俊幸, 中村典史, 中村誠司, 吉浦一紀

日本口腔科学会雑誌 56 ( 1 ) 186 - 186 2007.1

右側副耳下腺に生じた多形性腺腫の1例

見立英史, 大部一成, 笹栗正明, 中村典史, 川野真太郎, 小林家吉, 河津俊幸, 中村誠司

日本口腔腫瘍学会誌 18 ( 4 ) 165 - 165 2006.12

Long-term functional outcome of brachytherapy for carcinoma of the mobile tongue: focus on the atrophic change of irradiated tongue. International journal

Yusuke Urashima, Katsumasa Nakamura, Yoshiyuki Shioyama, Tomonari Sasaki, Saiji Ohga, Takashi Toba, Naonobu Kunitake, Tooru Chikui, Toshiyuki Kawazu, Tomomi Yamada, Hiromi Terashima, Hiroshi Honda

Japanese journal of clinical oncology 36 ( 11 ) 681 - 7 2006.11

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

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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Patency assessment of the internal jugular vein after neck dissection

T. Nagata, K. Matsunaga, T. Kawazu, S. Kawano, K. Oobu, M. Ohishi

International Journal of Oral and Maxillofacial Surgery 35 ( 5 ) 416 - 420 2006.5

Publishing type：Research paper (scientific journal)

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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Correlation between diagnostic accuracy and perceptibility

K Yoshiura, K Okamura, K Tokumori, E Nakayama, T Chikui, TK Goto, M Shimizu, T Kawazu

DENTOMAXILLOFACIAL RADIOLOGY 34 ( 6 ) 350 - 352 2005.11

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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Effects of the automatic exposure compensation on the proximal caries diagnosis

K Yoshiura, E Nakayama, M Shimizu, TK Goto, T Chikui, T Kawazu, K Okamura

DENTOMAXILLOFACIAL RADIOLOGY 34 ( 3 ) 140 - 144 2005.5

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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コンピュータ診断支援(CAD)を利用した学生教育用教材の開発

河津俊幸, 徳森謙二, 吉浦一紀

歯科放射線 45 ( 1 ) 31 - 31 2005.3

当科における口腔扁平上皮癌頸部リンパ節転移の診断および治療方法の変遷と治療成績の向上

中村誠司, 蔵原慎一, 筑井徹, 河津俊幸, 杉浦剛, 豊嶋健史, 林田淳之將, 白砂兼光

日本口腔科学会雑誌 54 ( 1 ) 84 - 85 2005.1

Imaging and diagnostic accuracy of cervical lymph node metastasis with oral cancer

KANDA Shigenobu, CHIKUI Toru, KAWAZU Toshiyuki, YUASA Kenji

Journal of Japanese Society of Oral Oncology 16 ( 3 ) 75 - 84 2004.9

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

Development of new sialendoscopy systems for endoscopic sialolithectomy and their clinical application

NAKAYAMA Eiji, KAWAZU Toshiyuki, NAKAMURA Norifumi, OKAMURA Kazutoshi, KANDA Shigenobu, OHISHI Masamichi

J.Jpn.Stomatol.Soc 53 ( 2 ) 81 - 86 2004

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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Interventional sialendoscopy: A new procedure for noninvasive insertion and a minimally invasive sialolithectomy Reviewed

Eiji Nakayama, Kenji Yuasa, Mahiro Beppu, Toshiyuki Kawazu, Kazutoshi Okamura, Shigenobu Kanda

Journal of Oral and Maxillofacial Surgery 61 ( 10 ) 1233 - 1236 2003.10

Computer-Assisted Diagnostic System Applied with ANFIS

Tanaka Takemasa, Kawazu Toshiyuki, Kanda Shigenobu

Journal of Biomedical Fuzzy Systems Association 5 ( 1 ) 49 - 54 2003

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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The combined use of US and MR imaging for the diagnosis of masses in the parotid region

TK Goto, K Yoshiura, E Nakayama, K Yuasa, O Tabata, T Nakano, T Kawazu, T Tanaka, K Miwa, M Shimizu, T Chikui, K Okamura, S Kanda

ACTA RADIOLOGICA 42 ( 1 ) 88 - 95 2001.1

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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Computed tomography and ultrasonography of metastatic cervical lymph nodes in oral squamous cell carcinoma Reviewed

K Yuasa, T Kawazu, T Nagata, S Kanda, M Ohishi, K Shirasuna

DENTOMAXILLOFACIAL RADIOLOGY 29 ( 4 ) 238 - 244 2000.7

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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Medical Imaging of Cervical Lymph Node Metastasis in Patients With Oral Cancer.

KANDA Shigenobu, YUASA Kenji, NAKAYAMA Eiji, KAWAZU Toshiyuki

Shika Hoshasen 40 ( 2 ) 109 - 121 2000

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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Clinical evaluation of "veraviewpocs" digital panoramic X-ray system.

M. Tatsumi, K. Yoshiura, K. Yuasa, O. Tabata, E. Nakayama, T. Kawazu, T. Chikui, M. Katoh, S. Kanda

International journal of computerized dentistry 3 ( 3 ) 183 - 195 2000

A new, simple method of making a spacer in interstitial brachytherapy for mobile tongue cancer Reviewed

Kenji Yuasa, Toshiyuki Kawazu, Masahiro Morita, Satoru Uehara, Naonobu Kunitake, Shigenobu Kanda

Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics 89 ( 4 ) 519 - 521 2000

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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Sonography for the detection of cervical lymph node metastases among patients with tongue cancer: Criteria for early detection and assessment of follow-up examination intervals Reviewed

Kenji Yuasa, Toshiyuki Kawazu, Naonobu Kunitake, Satoru Uehara, Junichi Omagari, Kazunori Yoshiura, Eiji Nakayama, Shigenobu Kanda

American Journal of Neuroradiology 21 ( 6 ) 1127 - 1132 2000

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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Papers - KAWAZU Toshiyuki