Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Toru Chikui Last modified date:2020.07.29

Associate Professor / Division of Maxillofacial Diagnostic and Surgical Sciences / Department of Dental Science / Faculty of Dental Science

1. Panyarak, W., Chikui, T., Tokumori, K., Yamashita Y, Kamitani T., Togao, O., Yoshiura, K., Utility of a diffusion kurtosis model in the differential diagnosis of orofacial tumours, Clinical Radiology, 2020.02, AIM: To compare the goodness of fit and correlations between diffusion kurtosis imaging (DKI) and a mono-exponential (ME) model, to compare the corrected apparent diffusion coefficient (Dapp) and apparent kurtosis (Kapp) of the DKI model, and the apparent diffusion coefficient (ADC) of the ME model among the various orofacial lesions, and to evaluate the diagnostic performances between the two models. MATERIALS AND METHODS: A total of 100 orofacial lesions underwent echo-planar diffusion magnetic resonance imaging (MRI) with four b-values. The goodness of fit was evaluated using Akaike information criterion. The correlations of the diffusion-derived parameters were evaluated. The diagnostic performance was analysed by receiver operating characteristics (ROC). RESULTS: The DKI model showed a significantly better goodness of fit than the ME model (p<0.0001). The Kapp had a strongly negative correlation with the Dapp (ρ=–0.749) and ADC (ρ=–0.938). A strongly positive correlation existed between the Dapp and ADC (ρ=0.906). All parameters differed significantly between benign tumours and malignant tumours (p<0.05). In differentiating benign tumours from the malignant tumours, the AUC of Dapp (0.871) was larger than that of ADC (0.805); however, a significant difference was not found (p=0.102). CONCLUSION: The DKI model had better goodness of fit than the ME model. Furthermore, the Dapp and Kapp were also characteristic for each pathological category; however, the DKI model did not yield a significantly higher diagnostic performance than the ME model, which might be related to the high correlation among the diffusion-derived parameters and wide variation among categories. .
2. Maehara, T., Murakami, Y., Kawano, S., Mikami, Y., Kiyoshima, T., Chikui, T., Kakizoe, N., Munemura, R., Nakamura, S., Osteoid osteoma of mandibular bone: Case report and review of the literature, Journal of Oral and Maxillofacial Surgery, Medicine, and Pathology, 10.1016/j.ajoms.2019.04.002, 31, 322-326, 322-326, 2019.09.
3. WannakamonPanyarak, Toru Chiku, Yasuo Yamashita, Takeshi Kamitani, Kazunori Yoshiura., Image Quality and ADC Assessment in Turbo Spin-Echo and Echo-Planar Diffusion-Weighted MR Imaging of Tumors of the Head and Neck, Academic Radiology,, 2018.12, Rationale and Objectives

We aimed to compare the distortion ratio (DR), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) between turbo spin-echo (TSE)-diffusion-weighted imaging (DWI) and echo-planar imaging (EPI)-DWI of the orofacial region and prove the usefulness of TSE-DWI for the differential diagnosis of orofacial lesions.
Materials and methods

The DR, SNR, and CNR of both sequences were compared in 42 cases. Then, the apparent diffusion coefficient (ADC) of various orofacial lesions obtained by TSE-DWI was investigated in 143 lesions.

In the first study, 38 of 42 cases were analyzed. TSE-DWI showed a significantly lower DR (p < 0.05) and higher SNR and CNR than EPI-DWI (p < 0.05), indicating the superiority of TSE-DWI. In the second study, 114 cases (79.3%) were successfully analyzed. When lesions were divided into cysts, benign tumors, squamous cell carcinoma, malignant lymphoma, and other malignant tumors (OT), significant differences were observed in all pairs of lesions (p < 0.05) except squamous cell carcinoma and OT (p = 0.877). The area under the curve for distinguishing benign from malignant tumors was 0.80 with a cutoff ADC of 1.29 × 10-3 mm²/s.

TSE-DWI produced better quality images than EPI-DWI. TSE-DWI yields the high possibility of obtaining ADC in the orofacial region, and this value was considered useful for the differential diagnosis of orofacial lesions..
4. Chikui T, Yamashita Y, Kise Y, Saito T, Okamura K, Yoshiura KBr J Radiol.., Estimation of proton density fat fraction of the salivary gland., Br J Radiol, doi: 10.1259/bjr.20170671., 91, 1085, 2018.05, OBJECTIVE:
Our first objective was to prove the validity of the six-point Dixon method for estimating the proton density fat fraction (PDFF) of the salivary gland. The second objective was to estimate the salivary gland PDFF using Dixon method to evaluate the pathological conditions.
At first, 12 volunteers underwent two types of sequences: single-voxel magnetic resonance spectroscopy and the Dixon method and the PDFFs obtained by the two methods were compared. Next, a total of 67 individuals [normal, n = 46; Sjögren's syndrome (SS), n = 11; and IgG4-related dacryoadenitis and sialadenitis (IgG4-DS), n = 4, parotitis, n = 6] were enrolled to estimate the parotid gland (PG) and submandibular gland (SMG) PDFF using the Dixon method.
This volunteer study demonstrated excellent correlation between two methods (R2 = 0.964, slope = 1.05). In the normal group, the PG-PDFF was correlated with the weight and body mass index (BMI) (ρ = 0.38, p = 0.0085; and ρ = 0.63, p < 0.0001). The SMG-PDFF was also correlated with the weight, BMI, and serum triglyceride (ρ = 0.37, p = 0.0067; ρ = 0.42, p = 0.0022; and ρ = 0.35, p = 0.024). The PG-PDFF of the SS group (48.2 ± 15.1%) was higher than that of any other groups; however, no significant difference was found due to the wide overlap. The SS group (39.0 ± 26.14%) also had significantly higher SMG-PDFF than the normal group (8.9 ± 5.4%), p < 0.0001) and IgG4-DS group (3.8 ± 2.3%), p = 0.020).
The Dixon method is a feasible method for estimating the PDFF and demonstrates fat accumulation in SMG in the SS group. Advances in knowledge: The PDFF obtained by the Dixon method is helpful for understanding the salivary gland pathological condition..
5. Takafumi Hayashi, Yoshinori Arai, Toru Chikui, Sachiko Hayashi-Sakai, Kazuya Honda, Hiroko Indo, Taisuke Kawai, Kaoru Kobayashi, Shumei Murakami, Masako Nagasawa, Munetaka Naitoh, Eiji Nakayama, Yutaka Nikkuni, Hideyoshi Nishiyama, Noriaki Shoji, Shigeaki Suenaga, Ray Tanaka, ,, Clinical guidelines for dental cone-beam computed tomography, Oral Radiology, 10.1007/s11282-018-0314-3, 1-16, 2018.01, Dental cone-beam computed tomography (CBCT) received regulatory approval in Japan in 2000 and has been widely used since being approved for coverage by the National Health Insurance system in 2012. This imaging technique allows dental practitioners to observe and diagnose lesions in the dental hard tissue in three dimensions (3D). When performing routine radiography, the examination must be justified, and optimal protection should be provided according to the ALARA (as low as reasonably achievable) principles laid down by the International Commission on Radiological Protection. Dental CBCT should be performed in such a way that the radiation exposure is minimized and the benefits to the patient are maximized. There is a growing demand for widespread access to cutting-edge health care through Japan’s universal health insurance system. However, at the same time, people want our limited human, material, and financial resources to be used efficiently while providing safe health care at the least possible cost to society. Japan’s aging population is expected to reach a peak in 2025, when most of the baby boomer generation will be aged 75 years or older. Comprehensive health care networks are needed to overcome these challenges. Against this background, we hope that this text will contribute to the nation’s oral health by encouraging efficient use of dental CBCT..
6. Hiroko Furuhashi, Toru Chikui, Daisuke Inadomi, Tomoko Shiraishi, Kazunori Yoshiura, Fundamental tongue motions for trumpet playing a study using cine magnetic resonance imaging (Cine MRI), Medical Problems of Performing Artists, 10.21091/mppa.2017.4038, 32, 4, 201-208, 2017.12, OBJECTIVE: Though the motions of structures outside the mouth in trumpet performance have been reported, the dynamics of intraoral structures remain unelucidated. This study explored the tongue's movement in trumpet playing using cine magnetic resonance imaging (cine MRI) and demonstrated the effects of intraoral anatomical structures on changes in pitch and dynamics. METHODS: Cine MRI was applied to 18 trumpet players, who were divided into two groups (7 beginner, 11 advanced) based on their ability to play a certain high note. They were instructed to play a custom-made MRI-compatible simulated trumpet. Pitch-change tasks and dynamics-change tasks were assigned. The positions of the anatomical points and intraoral areas were identified on outlined images, and the changes associated with each task were evaluated. RESULTS: A forward and upward projection of the tongue was observed in the production of higher pitches, and there were no significant differences in all areas. In louder dynamics, a backward and downward bending of the tongue occurred, the tongue area became smaller (p<0.001), and the oral cavity area became larger (p<0.001). No significant differences between beginner and advanced trumpet players were seen in the changes in pitch and dynamics. CONCLUSION: It was demonstrated using cine MRI that certain tongue movements were associated with each task. Tongue protrusion in the production of higher pitch and bending in louder dynamics can be rationalized using acoustics theory and the movements of anatomical structures. These findings seem to be consistent regardless of the player's proficiency..
7. Yoshitaka Kise, Toru Chikui, Yasuo Yamashita, Kouji Kobayashi, Kazunori Yoshiura, Clinical usefulness of the mDIXON Quant the method for estimation of the salivary gland fat fraction: Comparison with MR spectroscopy., Br J Radiol.,, 2017.07, To estimate the fat fraction (FF) in the salivary glands (SGs) by the mDIXON method and the MRS method, and to compared the results.
Sixteen healthy volunteers were enrolled. mDIXON Quant and MRS (point-resolved spectroscopy: PRESS) with a single TE were employed to measure the FF in the parotid gland (PG) and submandibular gland (SMG). Multiple TEs were applied in 10 volunteers to correct for T2 decay. In addition, we assumed that the 1.3 ppm peak accounted for 60% of the total fat peak and estimated the FF (MRS all) as a gold standard. On mDIXON Quant images, VOIs were set on the bilateral SGs and we obtained the FF (mDIXON) of each VOI.
There was a strong correlation between the results of the mDIXON Quant method and the MRS (single TE) method (R2=0.960, slope=0.900). Using PRESS with multiple TEs, there was also a strong correlation between FF (mDIXON) and FF (MRS all) (R2=0.963, slope=1.18). FF (MRS all) was 24.9 ± 12.7% in the PG and 4.5 ± 3.0% in the SMG, while FF (mDIXON) was 29.4 ± 16.2% in the PG and 6.4 ± 4.7% in the SMG. There were no significant differences between the two methods, but the Bland-Altman plot showed that FF (mDIXON) was slightly larger than FF (MRS all) for small FF areas.
The mDIXON Quant method could be clinically useful for evaluating the FF of SGs, but the absolute values need careful interpretation Advance in knowledge: This study suggested the potential clinical usefulness of the mDIXON Quant method for the SGs..
8. Shintarou Kawano, Yanqun Zheng, Kazunari Oobu, Ryota Matsubara, Yuichi Goto, Toru Chikui, Tadamasa Yoshitake, Tamotsu Kiyoshima, Teppei Jinno, Yasuyuki Maruse, Eiji Mitate, Ryoji Kitamura, Hideaki Tanaka, Takeshi Toyoshima, Tsuyoshi Sugiura, Seiji Nakamura, Clinicopathological evaluation of pre-operative chemoradiotherapy with S-1 as a treatment for locally advanced oral squamous cell carcinoma, Oncology Letters, 10.3892/ol.2016.4411, 11, 5, 3369-3376, 2016.05, The administration of pre-operative chemotherapy with S-1 and concurrent radiotherapy at a total dose of 30 Gy was clinicopathologically evaluated as a treatment for locally advanced oral squamous cell carcinoma (OSCC) in the present study. The participants comprised 81 patients with OSCC, consisting of 29 patients with stage II disease, 12 patients with stage III disease and 40 patients with stage IV disease. All patients received a total radiation dose of 30 Gy in daily fractions of 2 Gy, 5 times a week, for 3 weeks, and the patients were concurrently administered S-1 at a dose of 80-120 mg, twice daily, over 4 consecutive weeks. Radical surgery was performed in all cases at 2-6 weeks subsequent to the end of pre-operative chemoradiotherapy. The most common adverse event was oropharyngeal mucositis, but this was transient in all patients. No severe hematological or non-hematological toxicities were observed. The clinical and histopathological response rates were 70.4 and 75.3%, respectively. Post-operatively, local failure developed in 6 patients (7.4%) and neck failure developed in 2 patients (2.5%). Distant metastases were found in 7 patients (8.6%). The overall survival rate, disease-specific survival rate and locoregional control rate at 5 years were 87.7, 89.9 and 90.6%, respectively. Locoregional recurrence occurred more frequently in patients that demonstrated a poor histopathological response compared with patients that demonstrated a good response (P<0.01). These results indicate that pre-operative S-1 chemotherapy with radiotherapy at a total dose of 30 Gy is feasible and effective for patients with locally advanced OSCC, and that little or no histopathological response may be a risk factor for locoregional recurrence in this treatment..
9. Yasuyuki Maruse, Shintarou Kawano, Tamotsu Kiyoshima, Yuichi Goto, Ryota Matsubara, Toru Chikui, Daigo Yoshiga, Seiji Nakamura, Case of mucoepidermoid carcinoma of the sublingual gland accompanied with extensive dystrophic calcification and intratumoral bone formation, Head and Neck Surgery, 10.1002/hed.24036, 37, 11, E161-E164, 2015.11, Background Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy. Although the histopathological findings are diverse, no case of salivary MEC accompanied with bone formation has been reported. Herein, we present the first case of MEC with intratumoral bone formation. Methods and Results A case of a 75-year-old female patient with an asymptomatic mass of the oral floor is presented. Enhanced CT revealed a tumorous mass with radiopaque materials in the oral floor. A pathological diagnosis of MEC was obtained by biopsy. Radical surgery was performed with the patient under general anesthesia. The resected specimen was finally diagnosed as MEC. Histopathologically, hyalinization, and dystrophic calcification were conspicuous within the stromal components of the tumor. Interestingly, ectopic bone formation was also found in the tumor tissues. Bony materials with osteocyte-like cells were also observed in a series of dystrophic calcification. Conclusion These findings suggest that bony materials are associated with dystrophic calcification..
10. Tomoko Shiraishi, Toru Chikui, Daisuke Inadomi, Marie Hashimoto, Chika Horio, Toyohiro Kagawa, Kunihiro Miwa, Kenji Yuasa, MRI findings of extranodal malignant lymphoma and squamous cell carcinoma in the head and neck regions, Oral Radiol, 10.1007/s11282-015-0219-3, 2015.07, Abstract
Objectives To compare magnetic resonance imaging (MRI) findings between patients with malignant lymphoma (ML) and squamous cell carcinoma (SCC) in the head and neck regions, and to show the characteristic findings for ML.
Methods We analyzed 10 lesions in nine patients with ML and 25 lesions in 25 patients with SCC. Diffusion- weighted imaging, T1-weighted imaging, and T2-weighted imaging were performed for all lesions. We estimated the apparent diffusion coefficients (ADCs) with b-factors of 0, 500, and 1000 s/mm2, and obtained the means and standard deviations. In 29 cases, dynamic contrast-enhanced MRI (DCE-MRI) was performed and time–intensity curves were obtained. The peak time, maximum-to-initial ratio (MI ratio), end-to-maximum ratio, and end-to-initial ratio (EI ratio) were estimated. Receiver-operating characteristic analyses were performed to estimate the diagnostic power for these indices.
Results The mean ADC for ML (0.762 ± 0.126 9 10-3 mm2/s) was significantly lower than that for SCC (1.24 ± 0.22 9 10-3 mm2/s, p \ 0.0001). ML had a smaller MI ratio (2.13 ± 0.26) and smaller EI ratio (1.90 ± 0.29) than SCC (MI ratio: 2.46 ± 0.38, p = 0.033; EI ratio: 2.19 ± 0.29, p = 0.025). The area under the curve for the mean ADC (0.989) was higher than those for the MI ratio (0.779) and EI ratio (0.792). Conclusions The most characteristic findings for ML were extremely low ADCs. If the ADCs cannot be esti- mated because of severe susceptibility artifacts, DCE-MRI provides an alternative index for differentiating ML from SCC..
11. Yoshikazu Hayashi, Masafumi Moriyama, Takashi Maehara, Yuichi Goto, Shintarou Kawano, Miho Ohta, Akihiko Tanaka, Sachiko Furukawa, Hayashida Jun-Nosuke, Tamotsu Kiyoshima, Mayumi Shimizu, Toru Chikui, Seiji Nakamura, A case of mantle cell lymphoma presenting as IgG4-related dacryoadenitis and sialoadenitis, so-called Mikulicz's disease, World Journal of Surgical Oncology, 10.1186/s12957-015-0644-0, 13, 1, 2015.07, Background: Mantle cell lymphoma (MCL) is a relatively uncommon type of non-Hodgkin lymphoma. It develops in the outer edge of a lymph node called the mantle zone. In contrast, IgG4-related dacryoadenitis and sialoadenitis (IgG4-DS) is characterized by elevated serum IgG4 and persistent bilateral enlargement of lacrimal glands (LGs) and salivary glands (SGs), with infiltration of IgG4-positive plasma cells. Recent studies indicated the importance of differentiation between IgG4-DS and malignant lymphoma. Case presentation: An 82-year-old man was suspected of IgG4-DS because of a high serum IgG level (2174 mg/dL) and bilateral swelling of LGs and SGs. Lip biopsy and fine needle biopsy of submandibular gland were performed, and subsequently, MCL was diagnosed through the histopathological findings. Conclusions: MCL most commonly occurs in the Waldeyer ring, but rarely in the stomach, spleen, skin, LG, and SG. We report an unusual case of MCL involving LGs and SGs mimicking IgG4-DS, which suggests that IgG4 testing may be useful in the differentiation of IgG4-DS in the presence of bilateral swelling of LGs or SGs..
12. Toru Chiikui, Erina KItamoto, Yukiko Nishioka Kami, Shintaro Kawano, Kouji Kobayashi, Takeshi Kamitani, Makoto Obara, Kazunori Yoshiura, Dynamic contrast-enhanced MRI of oral squamous cell carcinoma: A preliminary study of the correlations between quantitative parameters and the clinical stage., Br J Radiol., org/10.1259/bjr.20140814, 2015.04, To probe the utility of dynamic contrast-enhanced (DCE) -MRI parameters in assessing the clinical characteristics of oral squamous cell carcinoma.
A total of 85 tumors were included. We applied the Tofts and Kermode model for the DCE-MRI data, and obtained three dependent parameters: the influx forward volume transfer constant into the extravascular extracellular space (EES) from the plasma (Ktrans), the fractional volume of EES per unit volume of tissue (ve) and the fractional volume of plasma (vp). We evaluated the correlations between these parameters and the clinical stages.
The T stage showed a negative correlation with the Ktrans (r = -0.2272, P = 0.0365), but it did not show a significant correlation with the other parameters. The N stage showed a negative correlation with Ktrans (r = -0.1948, P = 0.0404), and there were significant differences between N1 and N2+3 (0.119±0.027 min-1 vs 0.096±0.023 min-1, P = 0.0198) and between N0 and N2+3 (0.114±0.29 min-1 vs 0.096±0.023 min-1, P = 0.0288).
A decrease in the Ktrans at the primary site was found in advanced N stage cases, which might indicate that the hypoxic status cause a high possibility of the metastasis. Advances in knowledge: A decrease in the Ktrans at the primary site suggested the high possibility of an advanced N stage..
13. Erina Kitamoto, Toru Chikui, Shintaro Kawano, Masahiro Ohga, Kouji Kobayashi, Yoshio Matsuo, Takashi Yoshiura, Makoto Obara, Hiroshi Honda, Kazunori Yoshiura, The application of dynamic contrast-enhanced MRI and diffusion-weighted MRI in patients with maxillofacial tumors., Academic Radiology, org/10.1016/j.acra.2014.08.016, 22, 2, 210-216, 2015.02, To elucidate the characteristics of four types of tumors, including squamous cell carcinoma (SCC), malignant lymphoma (ML), malignant salivary gland tumors (MSGTs), and pleomorphic adenoma (Pleo), in the maxillofacial region using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted MRI (DW-MRI)data.
A total of 59 tumors were included in this research. DCE-MRI and DW-MRI were performed. We applied the Tofts and Kermode model (TK model) for the DCE-MRI data and obtained three dependent parameters: the influx forward volume transfer constant into the extravascular extracellular space from the plasma (K(trans)), the fractional volume of extravascular extracellular space per unit volume of tissue (ve), and the fractional volume of plasma (vp).
Among the K(trans) values, there were no significant differences between the three types of malignant tumors; however, there was a significant difference between the SCC and Pleo (P = .0099). The ve values of the Pleo were highest, with significant differences compared to the other categories (SCC, P = .0012; ML, P = .0017; and MSGT, P = .041). The ML had the lowest ve values, and there were significant differences between ML and the other two types of malignant tumors (SCC, P = .0278 and MSGT, P = .0062). In 14 (24%) cases, apparent diffusion coefficient (ADC) could not be measured because of poor image quality. The ADC values of the ML were lowest, whereas those of Pleo were highest, similar to that observed for ve.
The Pleo tumors had lower K(trans) values and higher ve values, which are useful for differentiating them from the malignant tumors. Moreover, the ve was also useful for establishing a diagnosis of ML..
14. Mayumi Shimizu, Dai Ogawa, Kazutoshi Okamura, Toshiyuki Kawazu, Chikui Toru, Kazunori Yoshiura, Dentigerous cysts with calcification mimicking odontogenic tumors: differential diagnosis by CT, Oral Radiology, 10.1007/s11282-014-0173-5, 2014.04, Objective
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..
15. Chikui Toru, Masahiro Ohga, Shiro Kitamoto, Tomoko Shiraishi, Shintaro Kawano, Takashi Yoshiura, Kazunori Yoshiura, Quantification of diffusion and permeability of MRI in the head and neck region, 2014.03, Diffusion Weighted Image (DWI) has various roles such as tissue characterization, the prediction and monitoring of the response to treatment and
differentiation of recurrent tumors from post-therapeutic changes. The malignant tumors have a lower ADC compared to benign lesions. Follow-up of early
response to cancer treatment is reflected in an ADC increase in the primary tumor and nodal metastases; whereas nonresponding lesions tend to reveal only
a slight increase or even a decrease in ADC during follow-up. However, there are many limitations regarding the performance of DWI in the head and neck
region, therefore, many attempts has been performed to overcome the flaws of the diffusion-weighted single-shot-echo planar imaging.
The pharmacokinetic analyses of dynamic contrast enhanced MRI (DCE-MRI) can provide physiological condition of the tissue, and Tofts and Kermode
Model has been applied to the head and neck region. Some researchers have used it for the prediction and monitoring of the tumor response to cancer therapy.
The general consensus is that the early changes of these parameters during the early phase after the treatment are useful for the interpretation of the response
to the treatment. However, the parameters reported in the literature vary considerably; therefore, it is difficult to compare the values of the parameters among
research groups.
Both DWI and the pharmacokinetic analysis of the DCE-MRI have shown a wide range of potential benefits in this region, but more comparative studies
with established scan techniques and the quantification of the data are required..
16. Yukiko Kami, Toru Chikui, T. Shiraishi, D. Inadomi, M. Nishioka, K. Yuasa, Kazunori Yoshiura, A new method for displaying the lingual artery using high-resolution three-dimensional phase-contrast magnetic resonance angiography, International Journal of Oral and Maxillofacial Surgery, 10.1016/j.ijom.2013.04.011, 42, 11, 1494-1498, 2013.11, The aim of this study was to display the lingual artery superimposed on the anatomical image and to confirm its course and relation to the adjacent structures, noninvasively. Nineteen volunteers participated in the magnetic resonance imaging (MRI) study and one was excluded for excessive movement during scanning. A three-dimensional phase-contrast sequence (3D-PC) of magnetic resonance angiography (MRA) was used for vessel images, and a 3D-T1 high-resolution volume examination (THRIVE) was used for anatomical images. Colour-coded vessel images from 3D-PC MRA were superimposed on the 3D volume anatomical images, and the arterial course and relation to the adjacent structures were confirmed with multiplanar reconstructed cross-sectional (MPR) images. 3D-PC MRA images visualized the lingual artery in all 18 subjects and the sublingual artery in 14 subjects. In seven of 18 cases the bilateral sublingual arteries were shown to run side by side but had no contact with the sublingual veins. They ran together with the sublingual veins in four cases. Three cases showed irregular patterns. The bilateral sublingual arteries could not be identified in four cases. 3D-PC MRA images of the lingual artery superimposed on the anatomical images may be clinically useful to confirm its course and relationship to the adjacent structures before surgery, in order to prevent haemorrhage..
17. Eiji Mitate, Shintaro Kawano, Tamotsu Kiyoshima, Toshiyuki Kawazu, Toru Chikui, R Matsubara, Seiji Nakamura, Carcinoma ex pleomorphic adenoma of the upper lip: a case of an unusual malignant component of squamous cell carcinoma., 10.1186/1477-7819-11-234, 2013.09, Squamous cell carcinoma (SCC) as the malignant component of carcinoma ex pleomorphic adenoma (CXPA) occurring in upper lip is rare.This is the first report of CXPA of the upper lip with an unusual malignant component of SCC.

18. Eiji Mitate, Shintarou Kawano, Tamotsu Kiyoshima, Toshiyuki Kawazu, Toru Chikui, Yuichi Goto, Ryota Matsubara, Seiji Nakamura, Carcinoma ex pleomorphic adenoma of the upper lip
A case of an unusual malignant component of squamous cell carcinoma, World Journal of Surgical Oncology, 10.1186/1477-7819-11-234, 11, 2013.09, 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..
19. Chikui T, Obara M, Simonetti AW, Ohga M, Koga S, Kawano S, Matsuo Y, Kamintani T, Shiraishi T, Kitamoto E, Nakamura K, Yoshiura K., The principal of dynamic contrast enhanced MRI, the method of pharmacokinetic analysis, and its application in the head and neck region., Int J Dent, doi: 10.1155/2012/480659, 2012.11, The principal of dynamic contrast enhanced MRI, the method of pharmacokinetic analysis, and its application in the head and neck region..
20. Chikui T, Kitamoto E, Kawano S, Sugiura T, Obara M, Simonetti AW, Hatakenaka M, Matsuo Y, Koga S, Ohga M, Nakamura K, Yoshiura K, Pharmacokinetic analysis based on dynamic contrast-enhanced MRI for evaluating tumor response to preoperative therapy for oral cancer., J Magn Reson Imaging, doi: 10.1002/jmri.23704, 2012.06, 口腔扁平上皮ガンにおける、術前科学放射線の治療効果判定を、MRIのダイナミック撮影をコンパートメントモデル解析を用いる事により評価可能であるか検討した。治療高価判定としては、組織学的効果を大星、下里分類を用い、 gold standardとした。コンパートメントモデル解析から得られる、血管外細胞外のスペースveの変化量が、組織学的効果判定と相関する事を明らかにした。すなわわち、腫瘍細胞の減少による血管外細胞外スペースの割合の増加をMRでとらえる事が可能であることを示した。.
21. Matsubara R, Kawano S, Chikui T, Kiyosue T, Goto Y, Hirano M, Jinno T, Nagata T, Oobu K, Abe K, Nakamura S., Clinical Significance of Combined Assessment of the Maximum Standardized Uptake Value of F-18 FDG PET with Nodal Size in the Diagnosis of Cervical Lymph Node Metastasis of Oral Squamous Cell Carcinoma.
, Acad Radiol, 19, 6, 708-17, 2012.06.
22. Shiraishi T, Chikui T, Inadomi D, Kagawa T, Yoshiura K, Yuasa K., Evaluation of diffusion parameters and T2 values of the masseter muscle during jaw opening, clenching, and rest., Acta Radiologica., 53, 1, 81-6, 2012.02.
23. Okamura, K; Yoshiura, K; Tatsumi, M; Kawazu, T; Chikui, T; Shimizu, M ; Goto, TK., A new method for evaluating perceptible contrast information in digital intraoral radiographic systems., ORAL RADIOLOGY, 10.1007/s11282-011-0068-7 , 27, 2, 98-101 , 2012.02.
24. Kami YN, Chikui T, Okamura K, Kubota Y, Oobu K, Yabuuchi H, Nakayama E, Hashimoto K, Yoshiura K, Imaging findings of neurogenic tumours in the head and neck region., Dentomaxillofac Radiol, 10.1259/dmfr/81000210 , 41, 1, 18-23, 2012.01.
25. Chikui T, Kawano S, Kawazu T, Hatakenaka M, Koga S, Ohga M, Matsuo Y, Sunami S, Sugiura T, Shioyama Y, Obara M, Yoshiura K., Prediction and monitoring of the response to chemoradiotherapy in oral squamous cell carcinomas using a pharmacokinetic analysis based on the dynamic contrast-enhanced MR imaging findings., Eur Radiol, DOI: 10.1007/s00330-011-2102-x, 2011 Aug;21(8), 2011.08.
26. Tutsumi K, Chikui T, Okamura K, Yoshiura K., Accuracy of Linear Measurement and the Measurement Limits of Thin Objects with Cone Beam Computed Tomography: Effects of Measurement Directions and of Phantom Locations in the Fields of View., J ORAL MAX IMPL, 2011.02.
27. Shiraishi T, Chikui T, Yoshiura K, Yuasa K., Evaluation of T2 values and apparent diffusion coefficient of the masseter muscle by clenching., Dentomaxillofac Radiol. , 40, (1), 35-41., 2011.01.
28. TORU CHIKUI, TOMOKO SHIRAISHI, TAKAHIRO ICHIHARA, TOSHIYUKI KAWAZU, MASAMITSU HATAKENAKA, YUKIKO KAMI, KENJI YUASA , KAZUNORI YOSHIURA, Effect of clenching on T2 and diffusion parameters of the masseter muscle, Acta Radiologica, 51, 1, 58-63, 2010.01.
29. Toru Chikui, Mayumi Shimizu, Toshiyuki Kawazu, Kazutoshi Okamura, Tomoko Shiraishi, Kazunori Yoshiura, A quantitative analysis of sonographic images of the salivary gland: A comparison between the sonographic findings and the sialographic findings, UltrasoundinMed.&Biol., 35(8):1257-1264, 2009.08.
31. TORU CHIKUI, KAZUTOSHI OKAMURA, KENJI TOKUMORI, SEIJI NAKAMURA, Quantitative Analyses of Sonographic images of the parotid gland in patient with Sjogren's syndrome., Ultrasound in Med. & Biol., Vol. 32, No. 5, pp. 617- 622, 2006, 2006.05.
32. Urashima Y, Nakamura K, Kunitake N, Shioyama Y, Sasaki T, Ooga S, Kuratomi Y, Yamamoto T, Kawazu T, Chikui T, Jingu K, Terashima H, Honda H, Is glossectomy necessary for late nodal metastases without clinical local recurrence after initial brachytherapy for N0 tongue cancer? A retrospective experience in 111 patients who received salvage therapy for cervical failure., Jpn J Clin Oncol., 2006 Jan;36(1):3-6. Epub 2006 Jan 17., 2006.01.
33. Chikui T, Tokumori K, Yoshiura K, 0obu K, Nakamura S, Nakamura K., Sonographic texture characterization of salivary gland tumors by fractal analyses., Ultrasound in Med.&Biol., 10.1016/j.ultrasmedbio.2005.05.012, 31, 10, 1297-1304, Vol. 31, No. 10, pp. 1297-1304, 2005, 2005.10.
34. 1. Toru Chikui, Mayumi Shimizu, Tazuko K. Goto, Eiji Nakayama, Kazunori Yoshiura, Shigenobu Kanda Kazunari Oobu, Seiji Nakamura., Interpretation of the origin of a submandibular mass by CT and MRI imaging, Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 10.1016/j.tripleo.2004.02.054, 98, 6, 721-729, 2004 Dec;98(6):721-9., 2004.12.
35. Toru Chikui, Toshiyuki Kawazu, Katsumasa Nakamura, Yuusuke Urashima, Kenji Yuasa, Shigenobu, Intraoral sonographic features of tongue cancer after radical radiotherapy, Eur J Radiol, 10.1016/j.ejrad.2004.01.012, 52, 3, 246-256, 2004 Dec;52(3):246-56., 2004.12.
36. Toru Chikui, Kenji Yuasa1, kenji Tokumori, Shigenobu Kanda, Naonobu Kunitake, Katsumasa Nakamura,, Change of sonographic findings on cervical lymph nodes before and after preoperative radiotherapy, European Radiology, 10.1007/s00330-003-2173-4, 14, 7, 1255-1262, (2004) 14:1255–1262, 2004.07.
37. Change of sonographic findings on cervical lymph nodes before and after preoperative radiotherapy.
38. Shimizu M., Tokumori K., Okamura K., Chikui T., Yoshiura K., Kanda S., Possibility of sialographic sonography: a Doppler phantom study, Oral Surg Oral Med Oral Pathol Oral Radiol Endod., 10.1067/moe.2001.113832, 91, 6, 719-727, Vol.91,No.6,pp.719-727, 2001.06.
39. TK., Yoshiura, K., Nakayama, E., Yuasa, K., Tabata, O., Nakano, T., Kawazu, T., Tanaka, T., Miwa, K., Shimizu, M., Chikui, T., Okamura, K., Kanda, The combined use of US and MR imaging for the diagnosis of masses in the parotid region, Acta Radiol., 10.1080/028418501127346305, 42, 1, 88-95, Vol.42,No.1,pp.88-95, 2001.01.
40. Tumor recurrence criteria for postoperative contrast-enhanced computed tomography after surgical treatment of oral cancer and flap repair.
41. Chikui T., Yonetsu K., Izumi M., Eguchi K., Nakamura T., Abnormal blood flow to the submandibular glands of patients with Sjogren's syndrome: Doppler waveform analysis., J Rheumatol., Vol.27,No.5,pp.1222-1228, 2000.05.
42. Chikui T., Yonetsu K., Nakamura T., Multivariate feature analysis of sonographic findings of metastatic cervical lymph nodes: contribution of blood flow features revealed by power Doppler sonography for predicting metastasis, AJNR Am J Neuroradiol., Vol.21,No.3,pp.561-567, 2000.05.
43. Tatsumi M., Yoshiura K., Yuasa K., Tabata O., Nakayama E., Kawazu T, Chikui T, Katoh M, Kanda S., Clinical evaluation of "veraviewpocs" digital panoramic X-ray system, Int J Comput Dent., Vol.3,No.3,pp.183-95, 2000.01.
44. Chikui T., Izumi M., Eguchi K., Kawabe Y., Nakamura T., Doppler spectral waveform analysis of arteries of the hand in patients with Raynaud's phenomenon as compared with healthy subjects, AJR Am J Roentgenol., Vol.172,No.6,pp.1605-1609, 1999.03.
45. K., Stamatakis, HC., Welander, U., McDavid, WD., Shi, XQ., Ban, S., Kawazu, T., Chikui, T., Kanda, Prediction of perceptibility curves of direct digital intraoral radiographic systems, Dentomaxillofac Radiol., 10.1038/sj.dmfr.4600450, 28, 4, 224-231, Vol.28,No.4,pp.224-231, 1999.01.
46. Yoshiura K., Kawazu T., Chikui T., Tatsumi M., Tokumori K., Tanaka T., Kanda S., Assessment of image quality in dental radiography, part 2: optimum exposure conditions for detection of small mass changes in 6 intraoral radiography systems, Oral Surg Oral Med Oral Pathol Oral Radiol Endod., 10.1016/S1079-2104(99)70305-7, 87, 1, 123-129, Vol.87,No.1,pp.123-129, 1999.01.
47. Chikui T., Yonetsu K., Yoshiura K., Miwa K., Kanda S., Ozeki S., Shinohara M., Imaging findings of lipomas in the orofacial region with CT ,US and MRI., Oral Surg Oral Med Oral Pathol Oral Radiol Endod., 10.1016/S1079-2104(97)90302-4, 84, 1, 88-95, Vol.84,No.1,pp.88-95, 1997.07.