Faculty Profiles - TAKESHITA Yohei

Papers - TAKESHITA Yohei

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Clinical anatomy of the submental vein. International journal

Soichiro Ishii, Norio Kitagawa, Shogo Kikuta, Eiji Iwata, Saw Kalyar Htike, Keiko Fukino, Yohei Takeshita, Kenji Mitsudo, R Shane Tubbs, Joe Iwanaga

Surgical and radiologic anatomy : SRA 47 ( 1 ) 127 - 127 2025.4

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

This review provides a comprehensive overview of the anatomy of the submental vein, synthesizing recent findings on its development, anatomical features, course, and clinical significance. Additionally, it introduces the mylohyoid triangle, a new anatomical landmark where the submental vein, submental artery, and the nerve to the mylohyoid muscle run in parallel. As an essential structure in head and neck reconstructive surgery, the submental vein exhibits considerable anatomical variability, primarily due to its complex developmental process. This review highlights the importance of understanding the anatomy of the submental vein and performing thorough preoperative evaluations to enhance surgical success.

DOI： 10.1007/s00276-025-03636-6

A case of a large venous ring around the mandibular condyle. International journal

Keitaro Nishi, Tatsuo Okui, Yohei Takeshita, Jingo Kusukawa, R Shane Tubbs, Joe Iwanaga

Surgical and radiologic anatomy : SRA 47 ( 1 ) 95 - 95 2025.3

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

Anatomical details regarding venous drainage of the head and neck are an important matter for surgeons to avoid unnecessary complications such as hemorrhage. This report describes a case of the large venous ring around the mandibular condyle found in the cadaver. The left maxillofacial region of a latex-injected embalmed male cadaver (82 years of age at death) was dissected. The large two maxillary veins ran lateral to the capsule and superior to the mandibular notch and coursed posteroinferiorly to merge, and one trunk was formed at the posterior border of the ramus. It then received the superficial temporal vein superiorly to form the retromandibular vein (RMV). In addition, three maxillary veins were drained from the pterygoid venous plexus (PVP), medial to the ramus, one maxillary vein drained from the PVP into the RMV trunk, while two maxillary veins drained from the PVP into the anterior division of the RMV. All five large veins lateral and medial to the condyle drained from the PVP into the RMV. The knowledge of such an anatomical variation might prevent intraoperative bleeding in the temporomandibular joint region.

DOI： 10.1007/s00276-025-03602-2

Evidence-Based Anatomical Terminology in Dentistry Developed by a Consortium of Experts. International journal

Joe Iwanaga, Sergey L Kabak, Puhan He, Yusuke Hamada, Shogo Kikuta, Yohei Takeshita, Rarinthorn Samrid, Thewarid Berkban, Norio Kitagawa, Junichiro Wada, Taku Toriumi, Yuki Matsushita, Soichiro Ibaragi, Mi-Sun Hur, Hee-Jin Kim

Clinical anatomy (New York, N.Y.) 2025.2

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

This article aimed to develop evidence-based anatomical terminology in dentistry agreed upon by experts in multiple fields and ultimately to bridge anatomy and clinical dentistry. A comprehensive list of dental anatomical terminology was detailed in table format, and specific terms of interest were highlighted with their respective literature review. The presence of teeth is a unique feature of the oral cavity where dental professionals work. Dentistry is a highly specialized field focusing on preserving the health of dentition and its supporting and surrounding structures. Thus, "teeth" and "mouth" related anatomical terms must be very specialized for dentistry. Many of the terms highlighted were clinical dental or alveolar-related terms that were not clearly established in the general anatomical terminology. The authors hope the evidence-based anatomical terminology in dentistry developed by a consortium of experts will be generally accepted worldwide and ultimately bridge the fields of anatomy and clinical dentistry.

DOI： 10.1002/ca.24260

Evaluation of CT Findings in Squamous and Non-Squamous Cell Carcinomas of the Maxillary Sinus

Yuka Asaumi, Mamiko Fujikura, Miki Hisatomi, Wlla E. Al-Hammad, Yohei Takeshita, Shunsuke Okada, Toshiyuki Kawazu, Yoshinobu Yanagi, Junichi Asaumi

Journal of Hard Tissue Biology 34 ( 1 ) 35 - 40 2025

Correction: Radiological assessment of the dissection area in supraomohyoid neck dissection. Reviewed International journal

Yohei Takeshita, Joe Iwanaga, Yoshio Ohyama, Soichiro Ibaragi, Yuki Matsushita, R Shane Tubbs, Norio Kitagawa, Toshiyuki Kawazu, Miki Hisatomi, Shunsuke Okada, Mamiko Fujikura, Junichi Asaumi

Surgical and radiologic anatomy : SRA 46 ( 12 ) 1993 - 1994 2024.12

Anatomical relationship between maxillary posterior teeth and the maxillary sinus in an Indonesian population: a CT scan study. Reviewed International journal

Erli Sarilita, Rizky Maulana Muhammad, Harry Galuh Nugraha, Nani Murniati, Harmas Yazid Yusuf, Yohei Takeshita, Junichi Asaumi

BMC oral health 24 ( 1 ) 1014 - 1014 2024.8

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

BACKGROUND: The anatomical proximity between the root apex of the maxillary posterior teeth and the maxillary sinus can lead to complications, including odontogenic maxillary sinusitis. While several studies have investigated similar variables in different populations, there is limited research on the Indonesian population. This study aimed to describe the anatomical position of the maxillary posterior teeth in relation to the floor of the maxillary sinus using CT scans. METHODS: A total of 122 patients (432 maxillary premolars and 1,282 maxillary molars) underwent CT scans to evaluate 1,711 roots. The vertical relationship between the root apex of the maxillary posterior teeth and the maxillary sinus was classified into three types: IS (inside sinus), CO (sinus contact), and OS (outside sinus). RESULTS: The IS type was predominantly found in the palatal roots of the first molars, accounting for 20% of the total roots in this type. The CO type was most frequently observed in the mesiobuccal roots of the second molars, representing 18% of the total roots in this type. The OS type was most commonly found in the first premolar, comprising 20% of the total roots in this type. CONCLUSIONS: The palatal roots of the first molars exhibited the highest frequency of proximity to the maxillary sinus. CT scans can effectively assess the relationship between the root apex of the posterior teeth and the maxillary sinus. CLINICAL RELEVANCE: Clinicians should consider this information comprehensively when planning treatments for maxillary molars.

DOI： 10.1186/s12903-024-04783-9

Lingual nerve revisited-A comprehensive review Part II: Surgery and radiology. Reviewed International journal

Kisho Ono, Takashi Nishioka, Kyoichi Obata, Yohei Takeshita, Chista Irani, Yuki Kunisada, Norie Yoshioka, Soichiro Ibaragi, R Shane Tubbs, Joe Iwanaga

Clinical anatomy (New York, N.Y.) 2024.8

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

The lingual nerve (LN) is a branch of the mandibular division of the fifth cranial nerve, the trigeminal nerve, arising in the infratemporal fossa. It provides sensory fibers to the mucous membranes of the floor of the mouth, the lingual gingiva, and the anterior two-thirds of the tongue. Although the LN should rarely be encountered during routine and basic oral surgical procedures in daily dental practice, its anatomical location occasionally poses the risk of iatrogenic injury. The purpose of this section is to consider this potential LN injury risk and to educate readers about the anatomy of this nerve and how to treat it.

DOI： 10.1002/ca.24211

Central dentinogenic ghost cell tumor of the maxilla: a case report with new imaging findings and review of the literature Reviewed

Suzuka Yoshida, Yohei Takeshita, Toshiyuki Kawazu, Miki Hisatomi, Shunsuke Okada, Mamiko Fujikura, Kyoichi Obata, Kiyofumi Takabatake, Saori Yoshida, Junichi Asaumi

Oral Radiology 2024.7

Authorship：Corresponding author Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC

Abstract

A dentinogenic ghost cell tumor (DGCT) is a rare benign odontogenic tumor that commonly shows characteristics of solid proliferation and has a relatively high risk of recurrence after surgical treatment. We herein report a case of a central DGCT that occurred in the maxilla and resulted in bone expansion. This study highlights new imaging findings (particularly magnetic resonance imaging) along with histopathological observations. In addition, we conducted a review of the existing literature on this rare tumor. A 37-year-old man developed swelling around the right cheek. A benign odontogenic tumor such as ameloblastoma was suspected based on the imaging examination findings (including bone expansion and the internal characteristics of the tumor) on panoramic imaging, computed tomography, and magnetic resonance imaging. The lesion was surgically excised from the right maxilla. Postoperative histopathological examination led to a definitive diagnosis of central DGCT. The tumor comprised epithelial neoplastic islands, resembling ameloblastoma, inside tight fibroconnective tissue; masses of ghost cells and formation of dentin were also observed. We had suspected that the minute high-density region around the molars on the imaging examinations represented alveolar bone change; however, it represented dentin formation. This led to difficulty diagnosing the lesion. Although DGCT may present characteristic findings on imaging examinations, its occurrence is infrequent, and in some cases, the findings may include the presence or absence of an impacted tooth without obvious calcification. The present case suggests that we should consider the possibility of an odontogenic tumor with calcification when high-density structures are observed inside the lesion.

DOI： 10.1007/s11282-024-00764-4

Other Link： https://link.springer.com/article/10.1007/s11282-024-00764-4/fulltext.html

Efficacy of Cisplatin–CXCR4 Antagonist Combination Therapy in Oral Cancer Reviewed

Saori Yoshida, Hotaka Kawai, Yamin Soe, Htoo Shwe Eain, Sho Sanou, Kiyofumi Takabatake, Yohei Takeshita, Miki Hisatomi, Hitoshi Nagatsuka, Junichi Asaumi, Yoshinobu Yanagi

Cancers 16 ( 13 ) 2326 - 2326 2024.6

Publishing type：Research paper (scientific journal) Publisher：MDPI AG

Cisplatin is a platinum-based compound that is widely used for treating inoperable oral squamous cell carcinoma (OSCC) in Japan; however, resistance to cisplatin presents a challenge and innovative approaches are required. We aimed to investigate the therapeutic potential of targeting the chemokine receptor CXCR4, which is involved in angiogenesis and tumor progression, using the CXCR4 inhibitor AMD3100, in combination with cisplatin. AMD3100 induced necrosis and bleeding in OSCC xenografts by inhibiting angiogenesis. We investigated the combined ability of AMD3100 plus cisplatin to enhance the antitumor effect in cisplatin-resistant OSCC. An MTS assay identified HSC-2 cells as cisplatin-resistant cells in vitro. Mice treated with the cisplatin-AMD combination exhibited the most significant reduction in tumor volume, accompanied by extensive hemorrhage and necrosis. Histological examination indicated thin and short tumor vessels in the AMD and cisplatin–AMD groups. These results indicated that cisplatin and AMD3100 had synergistic antitumor effects, highlighting their potential for vascular therapy of refractory OSCC. Antitumor vascular therapy using cisplatin combined with a CXCR4 inhibitor provides a novel strategy for addressing cisplatin-resistant OSCC.

DOI： 10.3390/cancers16132326

Anatomy of the Buccal Space: Surgical and Radiological Perspectives. Reviewed International journal

Chung Yoh Kim, Yohei Takeshita, Takuma Kugimoto, Hiroyuki Harada, Jin Seo Park, R Shane Tubbs, Joe Iwanaga

The Journal of craniofacial surgery 2024.6

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

Among the anatomical spaces in the head and neck area, the buccal space has often been studied in dental/oral surgery and cosmetic surgery because it contains the facial vessels, mandibular and facial nerves, and adipose tissue called the buccal fat pad. In addition, as the space can communicate with other spaces, it can be significant in infections. Although the anatomy of the buccal space has been reported in several studies, there have been discrepancies concerning its boundaries, and its communications have often been overlooked. The aim of this review is to examine the anatomy of buccal space including its boundaries, contents, continuity with adjacent spaces, and clinical significance. A literature review was performed on Google Scholar and PubMed. The literature has depicted the anterior, medial, and lateral boundaries more or less consistently, but descriptions of the posterior, superior, and inferior borders are controversial. The buccal space includes the facial arteries, veins, facial nerves, parotid duct, and lymph nodes, which can be described differently depending on definitions and the extent of the space. As it communicates with other anatomical spaces including the masticatory space, it can be a reservoir and a channel for infections and tumors. Buccal fat pads have various clinical applications, from a candidate for flap reconstruction to a target for removal for cosmetic purposes. This review will help understand the anatomy of the buccal space including its boundaries, residing structures, and communication with other spaces from surgical and radiological perspectives.

DOI： 10.1097/SCS.0000000000010411

Imaging characteristics of incidentally detected cosmetic surgery-derived foreign bodies on CT images in the maxillofacial region Reviewed

Miki Hisatomi, Yohei Takeshita, Yoshinobu Yanagi, Shunsuke Okada, Mamiko Fujikura, Suzuka Yoshida, Toshiyuki Kawazu, Junichi Asaumi

Oral Radiology 2024.4

Preliminary Study of Dental Caries Detection by Deep Neural Network Applying Domain-Specific Transfer Learning Reviewed

Toshiyuki Kawazu, Yohei Takeshita, Mamiko Fujikura, Shunsuke Okada, Miki Hisatomi, Junichi Asaumi

Journal of Medical and Biological Engineering 2024.2

Radiological assessment of the dissection area in supraomohyoid neck dissection Reviewed

Yohei Takeshita, Joe Iwanaga, Yoshio Ohyama, Soichiro Ibaragi, Yuki Matsushita, R. Shane Tubbs, Norio Kitagawa, Toshiyuki Kawazu, Miki Hisatomi, Shunsuke Okada, Mamiko Fujikura, Junichi Asaumi

Surgical and Radiologic Anatomy 2024

Authorship：Lead author,　Corresponding author Publishing type：Research paper (scientific journal)

Purpose: The current supraomohyoid neck dissection (SOHND) is performed above the omohyoid muscle to dissect levels I, II, and III in the levels of cervical lymph nodes. However, the anatomical boundary between levels III and IV is the inferior border of the cricoid cartilage. We investigated the anatomical relationship between the omohyoid muscle and cricoid cartilage using contrast-enhanced CT (CE-CT) images to assess the validity of the current SOHND. Methods: CE-CT images of the head and neck regions in patients were reviewed. The patients were divided into two groups: “malignant tumors” and “others”. The vertebral levels corresponding to the positions of anatomical structures such as the intersection of the omohyoid muscle and internal jugular vein (OM-IJ), and the inferior border of the cricoid cartilage (CC), were recorded. Results: The OM-IJ was located around the seventh cervical to the first thoracic vertebra. There was a significant difference between the malignant tumor and others groups in females (p = 0.036). The CC was located around the sixth to seventh cervical vertebrae. There was a significant sex difference in each group (malignant tumor: p < 0.0001; others: p = 0.008). Both sexes tended to have lower OM-IJ than CC, and females had significantly lower OM-IJ than males. Conclusion: This study provides clear anatomical evidence showing the difference between the SOHND dissection area and levels I, II, and III. It could be considered that in most cases SOHND invades level IV, not just levels I, II, and III, especially in female patients.

DOI： 10.1007/s00276-024-03453-3

Mylohyoid Muscle: Current Understanding for Clinical Management Part II: Clinical Anatomy, Radiology, and Surgical/Clinical Relevance. Reviewed International journal

Kyoichi Obata, Norio Kitagawa, Kisho Ono, Hideka Kanemoto, Keiko Fukino, Yohei Takeshita, Soichiro Ibaragi, R Shane Tubbs, Joe Iwanaga

The Journal of craniofacial surgery 2023.11

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

The mylohyoid is one of the suprahyoid muscles along with the geniohyoid, digastric, and stylohyoid muscles that lies between the anterior belly of the digastric muscle inferiorly and the geniohyoid superiorly. In Part II, the radiology and clinical/surgical importance of the mylohyoid muscle will be discussed.

DOI： 10.1097/SCS.0000000000009797

Mylohyoid Muscle: Current Understanding for Clinical Management-Part I: Anatomy and Embryology. Reviewed International journal

Kyoichi Obata, Norio Kitagawa, Kisho Ono, Hideka Kanemoto, Keiko Fukino, Yohei Takeshita, Soichiro Ibaragi, Richard S Tubbs, Joe Iwanaga

The Journal of craniofacial surgery 2023.11

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

The mylohyoid is one of the suprahyoid muscles, along with the geniohyoid, digastric, and stylohyoid muscles. It lies between the anterior belly of the digastric muscle inferiorly and the geniohyoid superiorly. In Part I, the anatomy and embryology of the mylohyoid muscle will be reviewed in preparation for the clinical discussion in Part II.

DOI： 10.1097/SCS.0000000000009812

An imaging‑based diagnostic approach to vascular anomalies of the oral and maxillofacial region Reviewed

Wlla Al‑Hammad, Mamiko Fujikura, Miki Hisatomi, Shunsuke Okada, Luciana Munhoz, Toshiyuki Kawazu, Yohei Takeshita, Mariko Fujita, Yoshinobu Yanagi, Jun-Ichi Asaumi

Oncology Letters 26 ( 3 ) 2023.7

分化度の異なる口腔扁平上皮癌におけるシスプラチンとCXCR4阻害剤併用の効果

吉田沙織, 河合穂高, 竹下洋平, 岡田俊輔, 藤倉満美子, 久富美紀, 河津俊幸, 長塚仁, 浅海淳一, 柳文修

日本口腔内科学会雑誌 28 ( 2 ) 106 - 106 2022.12

Collision tumor of small cell carcinoma and squamous cell carcinoma of the maxillary sinus: Case report. Reviewed International journal

Irfan Sugianto, Yoshinobu Yanagi, Miki Hisatomi, Shunsuke Okada, Yohei Takeshita, Babatunde Olamide Bamgbose, Junichi Asaumi

Molecular and clinical oncology 16 ( 5 ) 96 - 96 2022.5

Language：English

A collision tumor refers to the coexistence of two diagnostically distinct tumors in a common anatomic space. Collision tumors are rare in the oral and maxillofacial region. The present study reported on the case of an 82-year-old female with a collision tumor in the maxillary sinus consisting of small cell carcinoma (SmCC) and squamous cell carcinoma (SCC). Computed tomography (CT) imaging revealed a mass in the right maxillary sinus. The lesion exhibited heterogeneous low signal intensity (SI) on T1-weighted imaging (T1WI), high SI on short T1 inversion recovery and heterogeneous solid enhancement on contrast-enhanced T1WI. The histopathology result of a biopsy specimen confirmed SmCC. After the patient received a course of chemoradiotherapy, follow-up CT revealed a residual tumor. In a second surgery, a remaining tumor and histopathology revealed SCC with no evidence of SmCC. The final diagnosis was a collision tumor made up of SCC and SmCC.

DOI： 10.3892/mco.2022.2529

Ultrasound procedure for the diagnosis of mass lesions in the oral region. Reviewed

Yohei Takeshita, Toshiyuki Kawazu, Miki Hisatomi, Shunsuke Okada, Mamiko Fujikura, Saori Yoshida, Yuri Namba, Yudai Shimizu, Yoshinobu Yanagi, Junichi Asaumi

Oral radiology 2022.3

Authorship：Lead 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

Influence of mesiodens on adjacent teeth and the timing of its safe removal. Reviewed International journal

Majd Barham, Shunsuke Okada, Miki Hisatomi, Abdullah Khasawneh, Nouha Tekiki, Yohei Takeshita, Toshiyuki Kawazu, Mariko Fujita, Yoshinobu Yanagi, Junichi Asaumi

Imaging science in dentistry 52 ( 1 ) 67 - 74 2022.3

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

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

A Case of Odontogenic Myxoma of the Mandible with Expansion to the Alveolar Crest - Comparison of Imaging Findings and Pathological Findings: A Case Report Reviewed

Saori Yoshida, Yohei Takeshita, Toshiyuki Kawazu, Tatsushi Matsumura, Junichi Asaumi, Hitoshi Nagatsuka, Yoshinobu Yanagi

OPEN DENTISTRY JOURNAL 16 2022

Authorship：Corresponding author 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

What are the retromolar and bifid/trifid mandibular canals as seen on cone-beam computed tomography? Revisiting classic gross anatomy of the inferior alveolar nerve and correcting terminology. Reviewed International journal

Joe Iwanaga, Yohei Takeshita, Yuki Matsushita, Mi-Sun Hur, Soichiro Ibaragi, R Shane Tubbs

Surgical and radiologic anatomy : SRA 44 ( 1 ) 147 - 156 2021.12

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

PURPOSE: Since cone-beam computed tomography was developed, a number of radiological studies on the bifid mandibular canals (BMCs) and trifid mandibular canals (TMCs) have been reported. However, many of the suggested subtypes of the BMC described in the literature seem to be normal branches of the inferior alveolar nerve. This might be due to a lack of revisiting classic anatomical studies in the field of radiology. Therefore, such studies are revisited here. METHODS: A database search using PubMed and Google Scholar was conducted on BMC and TMC. Eighty-nine articles underwent full-text assessment. The reported three classifications of BMC and the six modified classifications were reviewed and compared to the intramandibular inferior alveolar nerve branches. RESULTS: Some subtypes of BMC and TMC simply represent normal inferior alveolar nerve branches, i.e., retromolar branch, molar branch (alveolar branch/dental branch), large mental branch, or communicating branch. Others such as Naitoh's type III BMC and forward canal might be a true BMC. CONCLUSION: We found that the bifid mandibular canal is an additional intramandibular canal running parallel to the mandibular canal with/without confluence with the main canal through comparison of classifications of BMC/TMC between the radiology and anatomy fields.

DOI： 10.1007/s00276-021-02862-y

Dynamic contrast-enhanced MRI as a predictor of programmed death ligand-1 expression in patients with oral squamous cell carcinoma Reviewed

Nouha Tekiki, Mariko Fujita, Tatsuo Okui, Hotaka Kawai, May Oo, Toshiyuki Kawazu, Miki Hisatomi, Shunsuke Okada, Yohei Takeshita, Majd Barham, Hitoshi Nagatsuka, Yoshinobu Yanagi, Jun-Ichi Asaumi

ONCOLOGY LETTERS 22 ( 5 ) 2021.11

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

Displacement of lower third molar into floor of mouth: a single institutional experience Reviewed International journal

Masanori Masui, Soichiro Ibaragi, Yohei Takeshita, Joe Iwanaga, Yuki Kunisada, Akira Sasaki

Oral and Maxillofacial Surgery 26 ( 3 ) 447 - 453 2021.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC

PURPOSE: The displacement of the tooth/tooth fragment into the floor of mouth sometimes happens during the lower third molar surgery and the patients are usually referred to oral and maxillofacial surgeons. To date, however, there is no consensus how to manage the displaced tooth due to the lack of available data. METHODS: In this study, we have retrospectively analyzed the management of the displaced lower third molar into the floor of mouth. Our institute experienced seven cases during 2010 to 2020. RESULTS: Incidence rate of the lingual nerve injury caused by displacement of the lower third molar was 1/7. Six patients out of seven underwent surgical removal of the displaced fragment. The direct approach was used when the fragment was palpable superficially and the fragment was horizontally located away from the lingual plate (2 cases), while when the fragment was not palpable, or was palpable and adjacent to the lingual plate, the lingual mucoperiosteal flap was selected (4 cases). CONCLUSION: We conclude that the palpation and preoperative diagnosis with computed tomographic images are significantly important to decide a better and most effective surgical approach.

DOI： 10.1007/s10006-021-01012-3

Other Link： https://link.springer.com/article/10.1007/s10006-021-01012-3/fulltext.html

The potential for facial artery injury during mandibular third molar extraction. An anatomical study using contrast-enhanced computed tomography. Reviewed International journal

Yohei Takeshita, Soichiro Ibaragi, Hirokazu Yutori, Jingo Kusukawa, R Shane Tubbs, Toshiyuki Kawazu, Junichi Asaumi, Joe Iwanaga

Clinical anatomy (New York, N.Y.) 34 ( 8 ) 1215 - 1223 2021.8

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

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

Mandibular canal versus inferior alveolar canal: A Delphi study. Reviewed International journal

Joe Iwanaga, Soichiro Ibaragi, Yohei Takeshita, Junichi Asaumi, Keith Horner, Thomas R Gest, R Shane Tubbs

Clinical anatomy (New York, N.Y.) 34 ( 7 ) 1095 - 1100 2021.4

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

The general principles of anatomical terminology indicate that the "mandibular canal" should be named the "inferior alveolar canal" as it accommodates the inferior alveolar neurovascular bundles. Therefore, we performed a Delphi study to evaluate the current understanding and use of the terminology in different geographical regions and areas of expertise and to determine the appropriate terminology for this bony canal. A Delphi panel was formed and questions sent and answered via email about: field of expertise (anatomy, oral surgery/oral and maxillofacial (OMF) surgery, oral radiology/OMF radiology, plastic surgery, ENT surgery, or dentistry with the exception of oral/OMF surgery and oral/OMF radiology), years of experience in the field of expertise, country currently working in, "what is the name of the bony canal that contains the inferior alveolar neurovascular bundle," and "what should the structure above be called, in general?" A total of 52 participants responded to the questionnaire. Half or more of the experts in anatomy, oral/OMF surgery, and ENT/plastic surgery considered "mandibular canal" to be the most appropriate name for this bony canal. In contrast, more than half of all experts in oral/OMF radiology and dentistry, that is, most fields of dentistry, considered "either mandibular canal or inferior alveolar canal" to be the appropriate name. The results of the Delphi study and general principles suggest that an alternative term for the "mandibular canal" should be "inferior alveolar canal."

DOI： 10.1002/ca.23740

Comprehensive review of lower third molar management: A guide for improved informed consent. Reviewed International journal

Joe Iwanaga, Yuki Kunisada, Masanori Masui, Kyoichi Obata, Yohei Takeshita, Kotaro Sato, Shogo Kikuta, Yushi Abe, Yuki Matsushita, Jingo Kusukawa, R Shane Tubbs, Soichiro Ibaragi

Clinical anatomy (New York, N.Y.) 34 ( 2 ) 224 - 243 2021.3

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

Lower third molar removal is the most commonly performed dental surgical procedure. Nevertheless, it is difficult to ensure that all the informed consent forms given to patients are based on the best evidence as many newer publications could change the conclusions of previous research. Therefore, the goal of this review article is to cover existing meta-analyses, randomized control trials, and related articles in order to collect data for improved and more current informed consent.

DOI： 10.1002/ca.23693

Assessment of Hounsfield unit in the differential diagnosis of odontogenic cysts. Reviewed International journal

Kyonori Uehara, Miki Hisatomi, Luciana Munhoz, Toshiyuki Kawazu, Yoshinobu Yanagi, Shunsuke Okada, Yohei Takeshita, Emiko Arita Saito, Junichi Asaumi

Dento maxillo facial radiology 50 ( 2 ) 20200188 - 20200188 2021.2

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

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

No convincing evidence for the presence of tubarial salivary glands: A letter to the editor regarding "The tubarial salivary glands: A potential new organ at risk for radiotherapy". Reviewed International journal

Joe Iwanaga, Soichiro Ibaragi, Keisuke Nakano, Yohei Takeshita, R Shane Tubbs

Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology 154 321 - 322 2021.1

Incidental findings in the thyroid gland on computed tomography images of the oral and maxillofacial region. Reviewed International journal

Abdullah Khasawneh, Yohei Takeshita, Miki Hisatomi, Toshiyuki Kawazu, Mariko Fujita, Shunsuke Okada, Yuri Namba, Yudai Shimizu, Yoshinobu Yanagi, Junichi Asaumi

Oncology letters 19 ( 3 ) 2005 - 2010 2020.3

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

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

Oropharyngeal adenoid cystic carcinoma invading the mandibular bone through the mandibular foramen. Reviewed

Yohei Takeshita, Shunsuke Okada, Miki Hisatomi, Hidenobu Matsuzaki, Hotaka Kawai, Yohei Noda, Jun Murakami, Mariko Fujita, Hitoshi Nagatsuka, Yoshinobu Yanagi, Junichi Asaumi

Oral radiology 35 ( 3 ) 335 - 340 2019.9

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

Adenoid cystic carcinoma (ACC) is a rare epithelial tumor of the head and neck region, and one of the most common malignant tumors of the salivary glands. ACC is a slow-growing tumor characterized by perineural invasion and often has a high-recurrence rate. We describe a case of oropharyngeal ACC invading the mandibular bone through the mandibular foramen that showed a rare pattern of origin and invasion. A 70-year-old woman complained of noise and pain around the right temporomandibular joint. Osteomyelitis was suspected on the initial imaging examinations, although the findings were slightly atypical. However, a mass was observed in the right oropharyngeal wall on subsequent imaging examinations, and mandibular bone invasion, rather than osteomyelitis, was additionally suspected. The mass in the right oropharyngeal wall and right mandible was surgically excised. On postoperative histopathological examination, the mass was finally diagnosed as ACC. As tumor cells were also observed around the inferior alveolar nerve, mandibular bone invasion through the mandibular foramen was suspected. An oropharyngeal ACC invading the mandibular bone through the mandibular foramen is extremely rare. The present case suggests that bone invasion should be considered carefully with several imaging examinations when a malignant tumor such as ACC is observed around the jaw bone.

DOI： 10.1007/s11282-018-0359-3

Determination of optimum exposure parameters for dentoalveolar structures of the jaws using the CB MercuRay system with cluster signal-to-noise analysis. Reviewed

Warangkana Weerawanich, Mayumi Shimizu, Yohei Takeshita, Kazutoshi Okamura, Shoko Yoshida, Gainer R Jasa, Kazunori Yoshiura

Oral radiology 35 ( 3 ) 260 - 271 2019.9

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

OBJECTIVE: To determine the optimum cone beam computed tomography exposure parameters for specific diagnostic tasks. METHODS: A Teflon phantom attached to a half-mandible in a large container was scanned in dental (D), implant (I), and panoramic (P) modes. An identical phantom in a small container was scanned in D mode. Both were scanned at 60, 80, 100, and 120 kV. We evaluated the image quality of five anatomical structures [dentinoenamel junction (1), lamina dura and periodontal ligament space (2), trabecular pattern (3), cortex-spongy bone junction (4), and pulp chamber and root canal (5)] and analyzed the diagnostic image quality with cluster signal-to-noise analysis. We then evaluated correlations between the two image qualities and calculated the threshold of acceptable diagnostic image quality. Optimum exposure parameters were determined from images with acceptable diagnostic image quality. RESULTS: For the small container, the optimum exposure parameters were D mode, 80 kV for (1), (3), and (4) and D mode, 100 kV for (5). For the large container, they were D mode, 120 kV for (1), (3), and (5) and D mode, 100 kV for (4). I mode, 120 kV reached the acceptable level for (4). No images reached the acceptable level for (2). CONCLUSIONS: No optimum exposure parameters were identified for the evaluation of the lamina dura and periodontal ligament space. D mode was sufficient for the other structures; however, the tube voltage required for each structure differed. Smaller patients required lower tube voltage. I mode, 120 kV may be used for larger lesions.

DOI： 10.1007/s11282-018-0348-6

Fourth molar: A retrospective study and literature review of a rare clinical entity. Reviewed International journal

Babatunde O Bamgbose, Shunsuke Okada, Miki Hisatomi, Yoshinobu Yanagi, Yohei Takeshita, Zahrau Saleh Abdu, Edugie J Ekuase, Jun-Ichi Asaumi

Imaging science in dentistry 49 ( 1 ) 27 - 34 2019.3

Language：English Publishing type：Research paper (scientific journal) Publisher：KOREAN ACAD ORAL & MAXILLOFACIAL RADIOLOGY

Purpose: The prevalence of supernumerary teeth has been reported to be between 0.1% and 3.8%. The aim of this study was to determine the prevalence, clinical significance, and associated pathologies of fourth molars based on a retrospective study and a literature review. Materials and Methods: A 5-year retrospective prevalence study was conducted at the Department of Oral Diagnosis and Dentomaxillofacial Radiology of Okayama University Hospital, Okayama, Japan. The study involved extracting data from the digital records of patients from January 1, 2013 through December 31, 2017. The sampling frame included all patients who had panoramic radiographs, cone-beam computed tomography (CT), and multislice CT images during the period under review. Results: A total of 26,721 cases were reviewed and 87 fourth molars were identified. The prevalence of fourth molars in the 5-year study at Okayama was calculated as 0.32%. The mean age of patients with a fourth molar was 30.43 years, and the male-to-female ratio was 1:0.98. The vast majority of cases were in the maxilla (92%) and had normal shapes (89.7%); furthermore, 82.8% of cases were unerupted. Conclusion: The prevalence of fourth molars in the study population was found to be 0.32%, and fourth molars occurred with approximately equal frequency in males and females. Fourth molars were more common in the maxilla and were predominantly unerupted and small.

DOI： 10.5624/isd.2019.49.1.27

Evaluation of cone-beam computed tomography diagnostic image quality using cluster signal-to-noise analysis. Reviewed

Warangkana Weerawanich, Mayumi Shimizu, Yohei Takeshita, Kazutoshi Okamura, Shoko Yoshida, Gainer R Jasa, Kazunori Yoshiura

Oral radiology 35 ( 1 ) 59 - 67 2019.1

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

OBJECTIVES: (1) We sought to assess correlation among four representative parameters from a cluster signal-to-noise curve (true-positive rate [TPR] corresponding to background noise, accuracy corresponding to background noise, maximum TPR, and maximum accuracy) and the diagnostic accuracy of the identification of the mandibular canal using data from observers in a previous study, under the same exposure conditions. (2) We sought to clarify the relationship between the hole depths of a phantom and diagnostic accuracy. METHODS: CBCT images of a Teflon plate phantom with holes of decreasing depths from 0.7 to 0.1 mm were analyzed using the FindFoci plugin of ImageJ. Subsequently, we constructed cluster signal-to-noise curves by plotting TPRs against false-positive rates. The four parameters were assessed by comparing with the diagnostic accuracy calculated from the observers. To analyze image contrast ranges related to detection of mandibular canals, we determined five ranges of hole depths, to represent different contrast ranges-0.1-0.7, 0.1-0.5, 0.2-0.6, 0.2-0.7 and 0.3-0.7 mm-and compared them with observers' diagnostic accuracy. RESULTS: Among the four representative parameters, accuracy corresponding to background noise had the highest correlation with the observers' diagnostic accuracy. Hole depths of 0.3-0.7 and 0.1-0.7 mm had the highest correlation with observers' diagnostic accuracy in mandibles with distinct and indistinct mandibular canals, respectively. CONCLUSIONS: The accuracy corresponding to background noise obtained from the cluster signal-to-noise curve can be used to evaluate the effects of exposure conditions on diagnostic accuracy.

DOI： 10.1007/s11282-018-0325-0

Prediction of detectability of the mandibular canal by quantitative image quality evaluation using cone beam CT. Reviewed International journal

Yohei Takeshita, Mayumi Shimizu, Gainer R Jasa, Warangkana Weerawanich, Kazutoshi Okamura, Shoko Yoshida, Kenji Tokumori, Junichi Asaumi, Kazunori Yoshiura

Dento maxillo facial radiology 47 ( 4 ) 20170369 - 20170369 2018.5

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：British Institute of Radiology

OBJECTIVES: To compare the results of a new quantitative image quality evaluation method that requires no observers with the results of receiver operating characteristic (ROC) analysis in detecting the mandibular canal (MC) in cone beam CT (CBCT) images. METHODS: A Teflon (polytetrafluoroethylene) plate phantom with holes of different depths was scanned with two CBCT systems. One CBCT system was equipped with an image intensifier (Experiment 1), and the other was equipped with a flat panel detector (Experiment 2). Holes that were above the threshold gray value (ΔG), calculated using just-noticeable difference (JND), were extracted. The number of extracted holes was used as the index of the image quality, and was compared with the Az values calculated by ROC analysis to detect the MC. RESULTS: The number of extracted holes reflected the influence of different scanning conditions, and showed a strong correlation with the Az values calculated by ROC analysis. Indices of the number of extracted holes corresponding to high Az values for detecting the MC were obtained in both experiments. CONCLUSIONS: Our image quality evaluation method applying JND to images of a standardized phantom is a quantitative method that could be useful for evaluating the detectability of the MC in CBCT images.

DOI： 10.1259/dmfr.20170369

Cluster signal-to-noise analysis for evaluation of the information content in an image. Reviewed International journal

Warangkana Weerawanich, Mayumi Shimizu, Yohei Takeshita, Kazutoshi Okamura, Shoko Yoshida, Kazunori Yoshiura

Dento maxillo facial radiology 47 ( 1 ) 20170147 - 20170147 2018.1

Language：English Publishing type：Research paper (scientific journal) Publisher：British Institute of Radiology

OBJECTIVES: (1) To develop an observer-free method of analysing image quality related to the observer performance in the detection task and (2) to analyse observer behaviour patterns in the detection of small mass changes in cone-beam CT images. METHODS: 13 observers detected holes in a Teflon phantom in cone-beam CT images. Using the same images, we developed a new method, cluster signal-to-noise analysis, to detect the holes by applying various cut-off values using ImageJ and reconstructing cluster signal-to-noise curves. We then evaluated the correlation between cluster signal-to-noise analysis and the observer performance test. We measured the background noise in each image to evaluate the relationship with false positive rates (FPRs) of the observers. Correlations between mean FPRs and intra- and interobserver variations were also evaluated. Moreover, we calculated true positive rates (TPRs) and accuracies from background noise and evaluated their correlations with TPRs from observers. RESULTS: Cluster signal-to-noise curves were derived in cluster signal-to-noise analysis. They yield the detection of signals (true holes) related to noise (false holes). This method correlated highly with the observer performance test (R2 = 0.9296). In noisy images, increasing background noise resulted in higher FPRs and larger intra- and interobserver variations. TPRs and accuracies calculated from background noise had high correlation with actual TPRs from observers; R2 was 0.9244 and 0.9338, respectively. CONCLUSIONS: Cluster signal-to-noise analysis can simulate the detection performance of observers and thus replace the observer performance test in the evaluation of image quality. Erroneous decision-making increased with increasing background noise.

DOI： 10.1259/dmfr.20170147

A Case of Schwannoma of the Submandibular Region. Reviewed International journal

Babatunde O Bamgbose, Akiko Sato, Yoshinobu Yanagi, Miki Hisatomi, Yohei Takeshita, Irfan Sugianto, Junichi Asaumi

The open dentistry journal 12 12 - 18 2018

Language：English Publishing type：Research paper (scientific journal) Publisher：Bentham Science Publishers B.V.

Background: We herein described a rare case of schwannoma of the hypoglossal nerve in the submandibular region with diagnostic imaging and histopathological findings. Case Report: A 31-years-old woman has had a palpable firm, rubbery, freely mobile mass in the submandibular region. Of imaging, MR images showed homogeneous isointensity on T1-weighted imaging (T1-WI), heterogeneous hypointensity on T2-WI, heterogeneous hyperintensity on short T1 inversion recovery (STIR), and heterogeneous enhancement on contrast-enhanced T1-WI. A clear capsule was observed on the margin and showed hypointense on T2-WI. Dynamic MRI showed heterogeneous gradual increased enhancement. The uptake of contrast medium was regionally slow. Diagnostic imaging using CT and MRI was suspected of salivary gland tumor or neurogenic tumor. In consideration of imaging diagnosis, a pleomorphic adenoma or a schwannoma was suspected. Final diagnosis was confirmed on the basis of histopathological finding and intraoperative findings. Conclusion: 1. Histopathologic examination is inevitable, because MR findings are not specific.2. Schwannomas were said to have specific MRI properties, including specific signs (split-fat sign, fascicular sign, target sign). However, they are not always observed.3. This case confirmed the differential diagnosis on the basis of the intraoperative finding that the tumor was continuous with the hypoglossal nerve.

DOI： 10.2174/1874210601812010012

ファントムおよび輝度弁別閾を用いたMDCTにおける硬組織最適撮影条件決定法 Reviewed

岡村和俊, 吉田祥子, 徳森謙二, 清水真弓, 竹下洋平, Warangkana Weerawanich, 吉浦一紀

歯科放射線 58 ( 2 ) 58 - 65 2018

Diagnostic Value of Fluid-Attenuated Inversion Recovery Magnetic Resonance Imaging for Multilocular Ameloblastoma Reviewed

Irfan Sugianto, Hironobu Konouchi, Yohei Takeshita, Shunsuke Okada, Risa Matsubara, Miki Hisatomi, Jun Murakami, Babatunde O. Bamgbose, Yoshinobu Yanagi, Junichi Asaumi

Journal of Hard Tissue Biology 27 ( 4 ) 275 - 280 2018

Effects of exposure parameters and slice thickness on detecting clear and unclear mandibular canals using cone beam CT. Reviewed International journal

Gainer R Jasa, Mayumi Shimizu, Kazutoshi Okamura, Kenji Tokumori, Yohei Takeshita, Warangkana Weerawanich, Kazunori Yoshiura

Dento maxillo facial radiology 46 ( 4 ) 20160315 - 20160315 2017.4

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

OBJECTIVES: The purpose of this study was to clarify the effects of exposure parameters and image-processing methods when using CBCT to detect clear and unclear mandibular canals (MCs). METHODS: 24 dry half mandibles were divided into 2 groups with clear and unclear MCs based on a previous CBCT study. Mandibles were scanned using a CBCT system with varying exposure parameters (tube voltages 60 kV, 70 kV and 90 kV; and tube currents 2 mA, 5 mA, 10 mA and 15 mA) to obtain a total of 144 scans. The images were processed with different slice thicknesses using ImageJ software (National Institutes of Health, Bethesda, MD). Five radiologists evaluated the cross-sectional images of the first molar region to detect the MCs. The diagnostic accuracy of varying exposure parameters and image-processing conditions was compared with the area under the curve (Az) in receiver-operating characteristic analysis. RESULTS: The Az values for clear MCs were higher than those for unclear MCs (p < 0.0001). With increasing exposure voltages and currents, Az values increased, but no significant differences were found with high voltages and currents in clear MCs (p = 1.0000 and p = 0.9340). The Az values of serial images were higher than those of overlaid images (p < 0.0001), and those for thicker slices were higher than those for thinner slices (p < 0.0001). CONCLUSIONS: Our findings indicate that detection of unclear MCs requires either higher exposure parameters or processing of the images with thicker slices. To detect clear MCs, lower exposure parameters can be used.

DOI： 10.1259/dmfr.20160315

A new method to evaluate image quality of CBCT images quantitatively without observers. Reviewed International journal

Yohei Takeshita, Mayumi Shimizu, Kazutoshi Okamura, Shoko Yoshida, Warangkana Weerawanich, Kenji Tokumori, Gainer R Jasa, Kazunori Yoshiura

Dento maxillo facial radiology 46 ( 3 ) 20160331 - 20160331 2017.3

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：BRITISH INST RADIOLOGY

OBJECTIVES: To develop an observer-free method for quantitatively evaluating the image quality of CBCT images by applying just-noticeable difference (JND). METHODS: We used two test objects: (1) a Teflon (polytetrafluoroethylene) plate phantom attached to a dry human mandible; and (2) a block phantom consisting of a Teflon step phantom and an aluminium step phantom. These phantoms had holes with different depths. They were immersed in water and scanned with a CB MercuRay (Hitachi Medical Corporation, Tokyo, Japan) at tube voltages of 120 kV, 100 kV, 80 kV and 60 kV. Superimposed images of the phantoms with holes were used for evaluation. The number of detectable holes was used as an index of image quality. In detecting holes quantitatively, the threshold grey value (ΔG), which differentiated holes from the background, was calculated using a specific threshold (the JND), and we extracted the holes with grey values above ΔG. The indices obtained by this quantitative method (the extracted hole values) were compared with the observer evaluations (the observed hole values). In addition, the contrast-to-noise ratio (CNR) of the shallowest detectable holes and the deepest undetectable holes were measured to evaluate the contribution of CNR to detectability. RESULTS: The results of this evaluation method corresponded almost exactly with the evaluations made by observers. The extracted hole values reflected the influence of different tube voltages. All extracted holes had an area with a CNR of ≥1.5. CONCLUSIONS: This quantitative method of evaluating CBCT image quality may be more useful and less time-consuming than evaluation by observation.

DOI： 10.1259/dmfr.20160331

輝度弁別閾を用いた画質評価法の開発 Reviewed

吉田祥子, 岡村和俊, 徳森謙二, 清水真弓, 竹下洋平, Warangkana Weerawanich, 吉浦一紀

歯科放射線 56 ( 1 ) 27 - 32 2016

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

平均的な観察者が識別可能な最小輝度差である輝度弁別閾(JND)を検出閾値の設定に利用した画質評価法を開発し、観察者評価に替わり得るか否かを検討した。撮影対象は厚さを1mmずつ増加させた12段のアルミニウム製ブロックで、計7個の直径1mmのホールを有していた。デジタル口内法X線画像システムはDigora、Digora Optime、YCR-21XGの3機種を使用して撮影し、解析および観察により検出されなかったホール数(ホール非検出数)を画質視標とした。開発した評価法では、JNDインデックスを用いてホール非検出数の理論値を算出した。その結果、JNDを利用した評価法は、画像処理を行った場合の機種間の比較には注意を要するものの、おおむね観察者と同様の評価が可能であることが示された。更に、観察値と解析値について回帰分析を行った結果、得られた回帰式の決定係数は0.80を超え、観察値は解析値により高い精度で推定できることが確認された。なお、解析値と観察値のばらつきを比較した結果、解析値のばらつきは著明に小さかった。

Other Link： https://search-tp.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2016&ichushi_jid=J00567&link_issn=&doc_id=20170529210006&doc_link_id=%2Fcg7dentr%2F2016%2F005601%2F006%2F0027-0032%26dl%3D0&url=https%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fcg7dentr%2F2016%2F005601%2F006%2F0027-0032%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

Effectiveness of imaging modalities for screening IgG4-related dacryoadenitis and sialadenitis (Mikulicz's disease) and for differentiating it from Sjögren's syndrome (SS), with an emphasis on sonography. Reviewed International journal

Mayumi Shimizu, Kazutoshi Okamura, Yoshitaka Kise, Yohei Takeshita, Hiroko Furuhashi, Warangkana Weerawanich, Masafumi Moriyama, Yukiko Ohyama, Sachiko Furukawa, Seiji Nakamura, Kazunori Yoshiura

Arthritis research & therapy 17 223 - 223 2015.8

Language：English Publishing type：Research paper (scientific journal) Publisher：BIOMED CENTRAL LTD

INTRODUCTION: The aim of this study was to clarify the effectiveness of various imaging modalities and characteristic imaging features in the screening of IgG4-related dacryoadenitis and sialadenitis (IgG4-DS), and to show the differences in the imaging features between IgG4-DS and Sjögren's syndrome (SS). METHODS: Thirty-nine patients with IgG4-DS, 51 with SS and 36 with normal salivary glands were enrolled. Images of the parotid and submandibular glands obtained using sonography, 2-[(18)F]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT), computed tomography (CT) and magnetic resonance imaging (MRI) were retrospectively analyzed. Six oral and maxillofacial radiologists randomly reviewed the arranged image sets under blinded conditions. Each observer scored the confidence rating regarding the presence of the characteristic imaging findings using a 5-grade rating system. After scoring various findings, diagnosis was made as normal, IgG4-DS or SS, considering all findings for each case. RESULTS: On sonography, multiple hypoechoic areas and hyperechoic lines and/or spots in the parotid glands and obscuration of submandibular gland configuration were detected mainly in patients with SS (median scores 4, 4 and 3, respectively). Reticular and nodal patterns were observed primarily in patients with IgG4-DS (median score 5). FDG-PET/CT revealed a tendency for abnormal (18)F-FDG accumulation and swelling of both the parotid and submandibular glands in patients with IgG4-DS, particularly in the submandibular glands. On MRI, SS had a high score regarding the findings of a salt-and-pepper appearance and/or multiple cystic areas in the parotid glands (median score 4.5). Sonography showed the highest values among the four imaging modalities for sensitivity, specificity and accuracy. There were significant differences between sonography and CT (p = 0.0001) and between sonography and FDG-PET/CT (p = 0.0058) concerning accuracy. CONCLUSIONS: Changes in the submandibular glands affected by IgG4-DS could be easily detected using sonography (characteristic bilateral nodal/reticular change) and FDG-PET/CT (abnormal (18)F-FDG accumulation). Even inexperienced observers could detect these findings. In addition, sonography could also differentiate SS. Consequently, we recommend sonography as a modality for the screening of IgG4-DS, because it is easy to use, involves no radiation exposure and is an effective imaging modality.

DOI： 10.1186/s13075-015-0751-x

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